WO2025082196A1 - 一种太阳能电池、太阳能电池组件和太阳能电池的制作方法 - Google Patents

一种太阳能电池、太阳能电池组件和太阳能电池的制作方法 Download PDF

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Publication number
WO2025082196A1
WO2025082196A1 PCT/CN2024/122489 CN2024122489W WO2025082196A1 WO 2025082196 A1 WO2025082196 A1 WO 2025082196A1 CN 2024122489 W CN2024122489 W CN 2024122489W WO 2025082196 A1 WO2025082196 A1 WO 2025082196A1
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Prior art keywords
passivation layer
electrode
solar cell
metal
metal crystal
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PCT/CN2024/122489
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English (en)
French (fr)
Inventor
党长伟
白明华
李慧
朱惠君
平飞林
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Xian Longi Solar Technology Co Ltd
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Xian Longi Solar Technology Co Ltd
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Priority to EP24861334.1A priority Critical patent/EP4576164A4/en
Priority to JP2025515860A priority patent/JP2026511282A/ja
Priority to DE212024000081.7U priority patent/DE212024000081U1/de
Priority to AU2024329874A priority patent/AU2024329874B2/en
Priority to US19/081,291 priority patent/US12439725B2/en
Publication of WO2025082196A1 publication Critical patent/WO2025082196A1/zh
Priority to US19/325,060 priority patent/US20260013262A1/en
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/10—Semiconductor bodies
    • H10F77/16—Material structures, e.g. crystalline structures, film structures or crystal plane orientations
    • H10F77/162—Non-monocrystalline materials, e.g. semiconductor particles embedded in insulating materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/311—Coatings for devices having potential barriers for photovoltaic cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F10/00—Individual photovoltaic cells, e.g. solar cells
    • H10F10/10—Individual photovoltaic cells, e.g. solar cells having potential barriers
    • H10F10/14—Photovoltaic cells having only PN homojunction potential barriers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F19/00—Integrated devices, or assemblies of multiple devices, comprising at least one photovoltaic cell covered by group H10F10/00, e.g. photovoltaic modules
    • H10F19/90—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers
    • H10F19/902—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers for series or parallel connection of photovoltaic cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/121—The active layers comprising only Group IV materials
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/128—Annealing
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/129—Passivating
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/134—Irradiation with electromagnetic or particle radiation
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/20—Electrodes
    • H10F77/206—Electrodes for devices having potential barriers
    • H10F77/211—Electrodes for devices having potential barriers for photovoltaic cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/311—Coatings for devices having potential barriers for photovoltaic cells
    • H10F77/315—Coatings for devices having potential barriers for photovoltaic cells the coatings being antireflective or having enhancing optical properties

Definitions

  • the present application relates to the technical field of solar cells, and in particular to a solar cell, a solar cell assembly and a method for manufacturing a solar cell.
  • a solar cell is a device that utilizes solar energy and directly converts light energy into electrical energy through the photoelectric effect or photochemical effect.
  • the above-mentioned solar cells include Tunnel Oxide Passivated Contact solar cells (TOPCon for short).
  • the doped passivation layer of the TOPCon cell is deposited with a thicker Poly layer, which results in a longer time for the carriers to pass through the passivation layer and severe light parasitic absorption, thus affecting the cell efficiency of the TOPCon cell.
  • the purpose of the present application is to provide a solar cell, a solar cell module and a method for manufacturing a solar cell, which are used to improve the carrier transmission efficiency and reduce the light parasitic absorption to ensure the cell efficiency of the TOPCon cell.
  • the present application provides a solar cell.
  • the solar cell includes: a semiconductor substrate, an ultra-thin dielectric layer, a passivation layer (also referred to as a doped semiconductor layer in the art), a first electrode and a metal crystal.
  • the semiconductor substrate has a relative light-receiving surface and a backlight surface, the ultra-thin dielectric layer is located on at least one of the backlight surface and the light-receiving surface of the semiconductor substrate, the passivation layer is located on the ultra-thin dielectric layer, the first electrode is located on the passivation layer, and the metal crystal is located in the passivation layer.
  • the metal crystal includes a first metal crystal, one end face of the first metal crystal is in contact with the ultra-thin dielectric layer, and the other end face of the first metal crystal is connected to the first electrode.
  • the solar cell provided by the present application can improve the carrier transmission efficiency, reduce or eliminate the loss of the opening voltage, and ensure the excellent electrical contact performance between the electrode and the passivation layer without thinning the passivation layer. Further, since one end face of the first metal crystal is in contact with the ultra-thin dielectric layer, the other end face of the first metal crystal is connected to the first electrode, forming a metal-ultra-thin dielectric-semiconductor structure. Since the first metal crystal is located in the passivation layer, the first metal crystal is in full contact with the passivation layer. Based on this, the filling factor can be optimized by controlling the ratio of the first metal crystal, and the opening voltage and the filling factor can be balanced.
  • the first metal crystal under the action of the first metal crystal, it is conducive to the movement of carriers to the first electrode, which speeds up the transmission rate of carriers and thus shortens the time required for carriers to pass through the passivation layer.
  • the first metal crystal does not pass through the ultra-thin dielectric layer into the semiconductor substrate, at this time, it can not only ensure that the ultra-thin dielectric layer is not destroyed, but also ensure that the function of the ultra-thin dielectric layer is not affected. That is, the good chemical passivation and tunneling effect of the ultra-thin dielectric layer are guaranteed.
  • the influence on the opening voltage can also be reduced to avoid the semiconductor substrate from being damaged, thereby ensuring that the function of the semiconductor substrate is not affected, and further ensuring the performance of the solar cell.
  • the first metal crystal abuts against the ultra-thin dielectric layer without destroying the structure of the ultra-thin dielectric layer, thus ensuring good chemical passivation and tunneling effect of the ultra-thin dielectric layer.
  • the ultra-thin dielectric layer acts as a tunneling transmission layer for majority carriers, and can transmit majority carriers in the semiconductor substrate through the ultra-thin dielectric layer.
  • the first metal crystal takes on the role of quickly transmitting majority carriers through the ultra-thin dielectric layer to the first electrode to ensure a higher fill factor.
  • the majority carrier transmission efficiency with good passivation structure can obtain a smaller contact resistivity and series resistance, thereby ensuring a higher battery efficiency.
  • a passivation layer is partially disposed on at least one of the backlight surface and the light-receiving surface.
  • a ratio of the number of first metal crystals to the total number of metal crystals is greater than or equal to 2% and less than or equal to 20%.
  • the width of the first metal crystal gradually decreases along the direction from the first electrode to the passivation layer.
  • the width of the first metal crystal gradually decreases along the direction from the first electrode to the passivation layer, which reduces the corrosion of the passivation layer and the semiconductor substrate, and reduces the metal recombination at the interface of the metal-ultra-thin dielectric layer. Furthermore, the width of the first metal crystal gradually increases along the direction from the passivation layer to the first electrode, which increases the contact area between the first metal crystal and the first electrode, which is beneficial to improve the transmission efficiency of the majority carriers transported by the first metal crystal to the first electrode.
  • the metal crystal further includes: a second metal crystal.
  • the second metal crystal is connected to the first electrode and is spaced apart from the first metal crystal.
  • the thickness of the second metal crystal is less than the thickness of the passivation layer, and the thickness direction of the second metal crystal and the thickness direction of the passivation layer are both consistent with the direction from the backlight surface to the light receiving surface.
  • the second metal crystal is less than the thickness of the passivation layer, the second metal crystal can be prevented from damaging the ultra-thin dielectric layer and the semiconductor substrate to ensure the performance of the solar cell.
  • the plurality of second metal crystals are distributed at intervals. And/or the ratio of the number of the second metal crystals to the total number of the metal crystals is greater than or equal to 50% and less than or equal to 90%.
  • the metal crystal further includes: a third metal crystal.
  • the third metal crystal is spaced apart from the first electrode, the ultra-thin dielectric layer, and the second metal crystal.
  • a plurality of third metal crystals are discretely distributed in the passivation layer; and/or, along the direction from the passivation layer to the first electrode, the spacing between the third metal crystal and the first electrode is smaller than the spacing between the third metal crystal and the ultra-thin dielectric layer; and/or, the ratio of the number of second metal crystals to the total number of metal crystals is less than or equal to 5%. and/or, the ratio of the average volume of the third metal crystals to the average volume of the second metal crystals is less than or equal to 10%.
  • the third metal crystals with smaller size are easy to separate from the first electrode body.
  • the third metal crystals are not expected to appear, but they are inevitable during the manufacturing process. Therefore, it is necessary to control the average volume and number of the third metal crystals within the above The value range is selected to reduce the influence of the third metal crystal on the efficiency of the solar cell.
  • the doped passivation layer when the passivation layer is a doped passivation layer, includes: a first heavily doped region and a first lightly doped region.
  • the first heavily doped region is connected to the first electrode.
  • the first lightly doped region is located on one side of the first heavily doped region, and the doping concentration of the first heavily doped region is greater than the doping concentration of the first lightly doped region.
  • the first heavily doped region is connected to the first electrode correspondingly, it is possible to ensure that the first electrode has good ohmic contact with the doped passivation layer to improve the fill factor. Furthermore, since the first shallowly doped region is not in contact with the first electrode, a non-metallic contact area is formed, and the doping concentration of the first shallowly doped region is low. Therefore, it is beneficial to reduce the Auger recombination of the non-metallic contact area and reduce the parasitic absorption of ultraviolet light by the doped passivation layer.
  • the silver paste printing line width used to form the first electrode during screen printing is wide, resulting in high unit consumption and high cost.
  • the silver paste printing line width used to form the first electrode can be appropriately narrowed to reduce the production cost.
  • the thickness of the doped passivation layer is greater than or equal to 50 nm and less than or equal to 200 nm.
  • the carrier transfer efficiency can be improved, the loss of the opening voltage can be reduced or eliminated, and the excellent electrical contact performance between the electrode and the passivation layer can be ensured without reducing the thickness of the doped passivation layer.
  • the thickness of the ultra-thin dielectric layer is greater than or equal to 1 nm and less than or equal to 2 nm.
  • the thickness direction of the ultra-thin dielectric layer is consistent with the direction from the light-receiving surface to the backlight surface.
  • the material of the ultra-thin dielectric layer includes one of silicon oxide, hafnium oxide, aluminum oxide, and silicon nitride.
  • the present application also provides a solar cell assembly, the solar cell assembly comprising two or more solar cells as described above, wherein the two or more solar cells are electrically connected in series, and the solar cell assembly further comprises a conductive wire for connecting the two or more solar cells.
  • a plurality of solar cells are electrically connected in series, and a projection of the conductive line in the plane where the passivation layer is located partially overlaps with a projection of the first electrode in the plane where the passivation layer is located.
  • the present application also provides a method for manufacturing a solar cell.
  • the method for manufacturing a solar cell comprises:
  • a semiconductor substrate is provided, wherein the semiconductor substrate has a light-receiving surface and a backlight surface opposite to each other.
  • an ultra-thin dielectric layer is formed on at least one of the backlight surface and the light-receiving surface of the semiconductor substrate; next, a passivation layer is formed on the ultra-thin dielectric layer; next, a first electrode is formed thereon; and metal crystals are formed in the passivation layer.
  • the metal crystals include a first metal crystal, one end face of the first metal crystal is in contact with the ultra-thin dielectric layer, and the other end face of the first metal crystal is connected to the first electrode.
  • the carrier transmission efficiency can be improved without thinning the passivation layer, the loss of the opening voltage can be reduced or eliminated, and the excellent electrical contact performance between the electrode and the passivation layer can be ensured.
  • one end face of the first metal crystal is in contact with the ultra-thin dielectric layer, and the other end face of the first metal crystal is connected to the first electrode, a metal-ultra-thin dielectric-semiconductor structure is formed. Since the first metal crystal is located in the passivation layer, the first metal crystal is in full contact with the passivation layer.
  • the filling factor can be optimized by controlling the ratio of the first metal crystal, and the opening voltage and the filling factor can be balanced. Further, under the action of the first metal crystal, it is conducive to the movement of carriers to the first electrode, which speeds up the transmission rate of carriers, thereby shortening the time required for carriers to pass through the passivation layer. In addition, since the first metal crystal does not pass through the ultra-thin dielectric layer into the semiconductor substrate, at this time, it can not only ensure that the ultra-thin dielectric layer is not destroyed, but also ensure that the function of the ultra-thin dielectric layer is not affected. That is, the good chemical passivation and tunneling effect of the ultra-thin dielectric layer are guaranteed. At the same time, the influence on the opening voltage can also be reduced to avoid the semiconductor substrate from being damaged, thereby ensuring that the function of the semiconductor substrate is not affected, and further ensuring the performance of the solar cell.
  • the first metal crystal abuts against the ultra-thin dielectric layer without destroying the structure of the ultra-thin dielectric layer, thus ensuring good chemical passivation and tunneling effect of the ultra-thin dielectric layer.
  • the ultra-thin dielectric layer acts as a tunneling transmission layer for majority carriers, and can transmit majority carriers in the semiconductor substrate through the ultra-thin dielectric layer.
  • the first metal crystal plays the role of quickly transmitting majority carriers through the ultra-thin dielectric layer to the first electrode. To ensure a higher fill factor, the good majority carrier transfer efficiency of the passivation structure can obtain a smaller contact resistivity and series resistance, thereby ensuring a higher battery efficiency.
  • a ratio of the number of first metal crystals to the total number of metal crystals is greater than or equal to 2% and less than or equal to 20%.
  • the width of the first metal crystal gradually decreases along the direction from the first electrode to the passivation layer.
  • the width of the first metal crystal gradually decreases along the direction from the first electrode to the passivation layer, which reduces the corrosion of the passivation layer and the semiconductor substrate, and reduces the metal recombination at the interface of the metal-ultra-thin dielectric layer. Furthermore, the width of the first metal crystal gradually increases along the direction from the first electrode to the passivation layer, which increases the contact area between the first metal crystal and the first electrode, which is beneficial to improve the transmission efficiency of the majority carriers transported by the first metal crystal to the first electrode.
  • the metal crystal further includes: a second metal crystal.
  • the second metal crystal is connected to the first electrode and is spaced apart from the first metal crystal.
  • the thickness of the second metal crystal is less than the thickness of the passivation layer, and the thickness direction of the second metal crystal and the thickness direction of the passivation layer are both consistent with the direction from the backlight surface to the light receiving surface.
  • the second metal crystal is less than the thickness of the passivation layer, the second metal crystal can be prevented from damaging the ultra-thin dielectric layer and the semiconductor substrate to ensure the performance of the solar cell.
  • the plurality of second metal crystals are distributed at intervals. And/or the ratio of the number of the second metal crystals to the total number of the metal crystals is greater than or equal to 50% and less than or equal to 90%.
  • the metal crystal further includes: a third metal crystal.
  • the third metal crystal is spaced apart from the first electrode, the ultra-thin dielectric layer, and the second metal crystal.
  • a plurality of third metal crystals are discretely distributed in the passivation layer; and/or, along the direction from the first electrode to the passivation layer, the spacing between the third metal crystal and the first electrode is smaller than the spacing between the third metal crystal and the ultra-thin dielectric layer; and/or, the ratio of the number of second metal crystals to the total number of metal crystals is less than or equal to 5%. and/or, the ratio of the average volume of the third metal crystals to the average volume of the second metal crystals is less than or equal to 10%.
  • the third metal crystals with smaller size are easy to separate from the first electrode body.
  • the third metal crystals are not expected to appear, but they will inevitably appear during the manufacturing process. Therefore, it is necessary to control the average volume and number of the third metal crystals within the above value range to reduce the impact of the third metal crystals on the efficiency of the solar cell.
  • the method for manufacturing a solar cell further includes:
  • the second doping source layer is regionally processed by laser irradiation process to form a first heavily doped region in the doped passivation layer; the remaining doped passivation layer is the first lightly doped region;
  • the first heavily doped region is connected to the first electrode correspondingly; and the doping concentration of the first heavily doped region is greater than the doping concentration of the first lightly doped region.
  • the first heavily doped region is connected to the first electrode correspondingly, it is possible to ensure that the first electrode has good ohmic contact with the doped passivation layer to improve the fill factor. Furthermore, since the first lightly doped region is not in contact with the first electrode, a non-metallic contact region is formed, and the doping concentration of the first lightly doped region is low. Therefore, it is beneficial to reduce the Auger recombination of the non-metallic contact region and reduce the parasitic absorption of ultraviolet light by the doped passivation layer.
  • the diffusion temperature in the doping diffusion process is greater than or equal to 800° C. and less than or equal to 830° C.
  • the diffusion temperature in the post-diffusion deposition process is greater than or equal to 820° C. and less than or equal to 850° C.
  • the thickness of the ultra-thin dielectric layer is greater than or equal to 1 nm and less than or equal to 2 nm.
  • the thickness direction of the ultra-thin dielectric layer is consistent with the direction from the light-receiving surface to the backlight surface.
  • the material of the ultra-thin dielectric layer includes one of silicon oxide, hafnium oxide, aluminum oxide, and silicon nitride.
  • FIG1 is a schematic structural diagram of a solar cell according to an embodiment of the present application.
  • FIG2 is an enlarged schematic diagram of a portion of the structure of FIG1 in an embodiment of the present application.
  • FIG. 3 is a second structural schematic diagram of a solar cell in an embodiment of the present application.
  • 51-a second metal crystal 52-a third metal crystal, 60-a second lightly doped region,
  • first and second are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as “first” or “second” may explicitly or implicitly include one or more of the features.
  • “multiple” means two or more, unless otherwise clearly and specifically defined.
  • "Several” means one or more, unless otherwise clearly and specifically defined.
  • the terms “installed”, “connected”, and “connected” should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • installed should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • the doped passivation layer of the TOPCon battery is deposited with a thicker Poly layer, it takes a long time for the carriers to pass through the passivation layer, and the parasitic light absorption is serious.
  • the phosphorus atom doping concentration of the Poly layer of the N-type TOPCon battery is about 3 ⁇ 6*E20 and is uniformly doped.
  • the Poly layer doped with high concentrations of phosphorus atoms will produce strong free carrier absorption for light in the long wavelength band (i.e., the wavelength range of 800nm ⁇ 1200nm), affecting the battery efficiency.
  • the electrodes are generally sintered and formed using a silver-containing slurry, and the electrodes are generally made of silver. Poor contact between the electrode and the Poly layer will reduce the fill factor.
  • an embodiment of the present application provides a solar cell.
  • the solar cell includes: a semiconductor substrate 1, an ultra-thin dielectric layer 2, a passivation layer 3, a first electrode 4 and a metal crystal 5.
  • the semiconductor substrate 1 has a light-receiving surface S1 and a backlight surface S2 opposite to each other, the ultra-thin dielectric layer 2 is located on at least one of the backlight surface S2 and the light-receiving surface S1 of the semiconductor substrate 1, the passivation layer 3 is located on the ultra-thin dielectric layer 2, the first electrode 4 is located on the passivation layer 3, and the metal crystal 5 is located in the passivation layer 3.
  • the metal crystal 5 includes a first metal crystal 50, wherein one end face of the first metal crystal 50 is in contact with the ultra-thin dielectric layer 2, and the other end face of the first metal crystal 50 is connected to the first electrode 4.
  • the passivation layer 3 is only shown as being arranged on the ultra-thin dielectric layer 2 at the backlight surface S2, it should be understood that the light-receiving surface S1 of the semiconductor substrate 1 may also be provided with a corresponding ultra-thin dielectric layer 2 and a passivation layer 3.
  • the semiconductor substrate may be a silicon substrate, which may be a single crystal silicon substrate in this embodiment, or a polycrystalline silicon substrate in other embodiments.
  • a passivation layer 3 may be partially disposed on at least one of the backlight surface S2 and the light receiving surface S1.
  • a passivation layer 3 may be partially disposed on the backlight surface S2.
  • a passivation layer 3 may also be partially disposed on the light receiving surface S1, or a passivation layer 3 may be partially disposed on both the backlight surface S2 and the light receiving surface S1.
  • the passivation layer 3 is disposed on the ultra-thin dielectric layer 2.
  • the first electrode is made of metal paste, for example, mainly formed by sintering silver paste. Specifically, the metal paste is first printed to a specified position by means of screen printing, laser transfer, etc., and then sintered to form an excellent contact between the electrode metal material and the passivation layer.
  • silver paste includes silver metal components, glass frit and other additives and solvents.
  • After printing the first electrode pattern it is dried to remove part of the organic part, and then sintered at a temperature greater than or equal to 700° C. and less than or equal to 800° C., preferably 740° C. After sintering, most of the silver electrode material is distributed on the surface of the passivation layer to form the first electrode.
  • the material of the metal crystal can be selected according to actual conditions.
  • the material of the metal crystal can be the same as the material of the first electrode, such as silver.
  • the solar cell can be a tunneling oxidation passivation contact solar cell.
  • the following description is taken as an example of a tunneling oxidation passivation contact solar cell. It should be understood that the following description is only for understanding and is not for specific limitation.
  • the solar cell provided in the embodiment of the present application can improve the carrier transmission efficiency, reduce or eliminate the loss of the opening voltage, and ensure the excellent electrical contact performance between the electrode and the passivation layer without thinning the passivation layer 3.
  • the other end face of the first metal crystal 50 is connected to the first electrode 4, forming a metal-ultra-thin dielectric-semiconductor structure. Since the first metal crystal 50 is located in the passivation layer 3, the first metal crystal 50 is in full contact with the passivation layer 3. Based on this, the fill factor can be optimized by controlling the ratio of the first metal crystal 50, and the opening voltage and the fill factor can be balanced. Further, under the action of the first metal crystal 50, it is beneficial for the carrier to move to the first electrode 4, which speeds up the carrier transmission rate, thereby shortening the time required for the carrier to pass through the passivation layer 3. Based on this, the carrier transfer efficiency can be improved and the light parasitic absorption can be weakened to ensure the cell efficiency of the TOPCon cell.
  • the first metal crystal 50 does not pass through the ultra-thin dielectric layer 2 into the semiconductor substrate 1, at this time, it can not only ensure that the ultra-thin dielectric layer 2 is not damaged, but also ensure that the function of the ultra-thin dielectric layer 2 is not affected. That is, the good chemical passivation and tunneling effect of the ultra-thin dielectric layer are guaranteed.
  • the impact on the opening voltage can also be reduced to avoid the semiconductor substrate 1 from being damaged, so as to ensure that the function of the semiconductor substrate 1 is not affected, and further ensure the performance of the solar cell.
  • the first metal crystal abuts against the ultra-thin dielectric layer without destroying the structure of the ultra-thin dielectric layer, thus ensuring good chemical passivation and tunneling effect of the ultra-thin dielectric layer.
  • the ultra-thin dielectric layer acts as a tunneling transmission layer for majority carriers, and can transmit majority carriers in the semiconductor substrate through the ultra-thin dielectric layer.
  • the first metal crystal plays the role of quickly transmitting majority carriers through the ultra-thin dielectric layer to the first electrode. To ensure a higher fill factor, the good majority carrier transfer efficiency of the passivation structure can obtain a smaller contact resistivity and series resistance, thereby ensuring a higher battery efficiency.
  • the structure of the passivation layer can be polycrystalline, amorphous or microcrystalline, etc.
  • the structure of the passivation layer is a polycrystalline structure, and the crystallization rate is above 98%.
  • the thickness of the polycrystalline silicon passivation layer is greater than or equal to 45nm and less than or equal to 200nm, and the thickness direction of the polycrystalline silicon passivation layer is consistent with the direction from the backlight surface to the light receiving surface.
  • the thickness can be 45nm, 50nm, 80nm, 100nm, 120nm, 150nm or 200nm, etc.
  • the thickness of the ultra-thin dielectric layer 2 is greater than or equal to 1 nm and less than or equal to 2 nm.
  • the thickness direction of the ultra-thin dielectric layer 2 is consistent with the direction from the light receiving surface S1 to the backlight surface S2. For example, 1 nm, 1.2 nm, 1.5 nm, 1.7 nm, 1.85 nm or 2 nm.
  • the material of the ultra-thin dielectric layer 2 includes one of silicon oxide, hafnium oxide, aluminum oxide, and silicon nitride.
  • the ultra-thin dielectric layer is a tunneling oxide layer.
  • the ratio of the number of the first metal crystals 50 to the total number of the metal crystals 5 is greater than or equal to 2% and less than or equal to 20%.
  • the ratio may be 2%, 5%, 8%, 12%, 15%, 17%, 18% or 20%, etc.
  • the carrier tunneling effect of the tunnel-polycrystalline may be prevented from being affected by the excessive number of the first metal crystals.
  • the first metal crystal 50 did not burn through the ultra-thin dielectric layer 2 into the semiconductor substrate 1.
  • the silver paste contains a considerable amount of metal silver and oxide glass frit components (such as lead oxide).
  • the metal silver and the glass frit enter the passivation layer 3.
  • the metal silver and its attached oxide enter the interface of the tunneling layer. Since the ultra-thin dielectric layer 2 is only a few nanometers in size and the silicon substrate is a dense single crystal structure, the metal silver cannot further pass through the tunneling layer into the silicon substrate.
  • the oxide accompanying the silver may undergo an oxidation reaction with the interface of the silicon substrate to form a silicon oxide layer between the silver crystal and the silicon substrate.
  • the width of the first metal crystal 50 gradually decreases.
  • the first metal crystal along the direction from the first electrode to the passivation layer, the first metal crystal
  • the width of the first metal crystal gradually decreases, which reduces the corrosion of the passivation layer and the semiconductor substrate and reduces the metal recombination at the interface of the metal-ultra-thin dielectric layer.
  • the width of the first metal crystal gradually increases, which increases the contact area between the first metal crystal and the first electrode, which is beneficial to improve the transmission efficiency of the first metal crystal transporting the majority carriers from the light-receiving surface to the backlight surface to the first electrode.
  • the first metal crystals 50 are approximately trapezoidal in shape.
  • one end surface of the first metal crystal 50 abuts against the ultra-thin dielectric layer 2, and the other end surface of the first metal crystal 50 penetrates into the first electrode 4, and the specific depth can be set according to actual conditions.
  • the metal crystal 5 further includes: a second metal crystal 51.
  • the second metal crystal 51 is connected to the first electrode 4 and is spaced apart from the first metal crystal 50.
  • the thickness of the second metal crystal 51 is less than the thickness of the passivation layer 3, and the thickness direction of the second metal crystal 51 and the thickness direction of the passivation layer 3 are both consistent with the direction from the backlight surface S2 to the light receiving surface S1. It should be understood that one end face of the second metal crystal 51 may also penetrate into the first electrode 4, wherein the size of the second metal crystal 51 penetrating into the first electrode 4 and the thickness of the second metal crystal 51 are set according to actual conditions and are not specifically limited here.
  • the second metal crystal 51 is less than the thickness of the passivation layer 3, the second metal crystal 51 can be prevented from damaging the ultra-thin dielectric layer 2 and the semiconductor substrate 1 to ensure the performance of the solar cell.
  • a plurality of second metal crystals 51 are distributed at intervals. And/or, the ratio of the number of second metal crystals 51 to the total number of metal crystals is greater than or equal to 50% and less than or equal to 90%. For example, the ratio may be 50%, 58%, 62%, 75%, 82% or 90%, etc.
  • the second metal crystal is less than the thickness of the passivation layer, the second metal crystal can be prevented from damaging the ultra-thin dielectric layer and the semiconductor substrate to ensure the performance of the solar cell.
  • the metal crystal 5 further includes: a third metal crystal 52.
  • the third metal crystal 52 is spaced apart from the first electrode 4, the ultra-thin dielectric layer 2, and the second metal crystal 51. That is, the third metal crystal 52 is neither connected to the first electrode 4 nor to the ultra-thin dielectric layer 2.
  • the carriers it is more conducive for the carriers to move to the first electrode 4, further accelerating the carrier transmission rate, and further shortening the time required for the carriers to pass through the passivation layer 3, so as to ensure the battery efficiency of the TOPCon battery. Furthermore, since the third metal crystals 52 and the ultra-thin dielectric layer 2 are spaced apart, the third metal crystals 52 can be prevented from damaging the ultra-thin dielectric layer 2 and the semiconductor substrate 1, so as to ensure the performance of the solar cell.
  • a plurality of third metal crystals 52 are discretely distributed in the passivation layer 3. And/or, along the direction from the first electrode 4 to the passivation layer 3, the spacing between the third metal crystal 52 and the first electrode 4 is smaller than the spacing between the third metal crystal 52 and the ultra-thin dielectric layer 2. In the embodiment of the present application, the spacing between the third metal crystal 52 and the first electrode 4 is smaller than half the thickness of the passivation layer 3. And/or, the ratio of the number of second metal crystals 51 to the total number of metal crystals is less than or equal to 5%.
  • the ratio of the average volume of the third metal crystals 52 to the average volume of the second metal crystals 51 is less than or equal to 10%.
  • the third metal crystals 52 of smaller size are easy to be separated from the main body of the first electrode 4.
  • the third metal crystals are not expected to appear, but they will inevitably appear during the manufacturing process. Therefore, it is necessary to control the average volume and number of the third metal crystals within the above value range to reduce the influence of the third metal crystals on the efficiency of the solar cell.
  • the first metal crystal 50 has the largest size compared to the second metal crystal 51 and the third metal crystal 52. Further, the first metal crystal 50, the second metal crystal 51 and the third metal crystal 52 are all distributed at intervals.
  • the light-receiving surface S1 of the solar cell has an emitter 64, which is obtained by having a doping type opposite to that of the semiconductor substrate 1.
  • the emitter 64 may have a single doping region, or may have a selective emitter structure, that is, it includes a second lightly doped region 60, and a second heavily doped region 61 in contact with the second electrode 9.
  • the doping concentration of the second heavily doped region 61 is greater than the doping concentration of the second lightly doped region 60.
  • a first passivation/anti-reflection stacked structure 70 is formed on the passivation layer 3, and the first electrode 4 is connected to the passivation layer 3 through the first passivation/anti-reflection stacked structure 70.
  • a second passivation/anti-reflection stacked structure 71 is also formed at the light-receiving surface S1 of the semiconductor substrate 1, and the second electrode 9 is connected to the second heavily doped region 61 through the second passivation/anti-reflection stacked structure 71.
  • the doped passivation layer 30 when the passivation layer is a doped passivation layer 30, the doped passivation layer 30 includes: a first heavily doped region 63 and a first lightly doped region 62.
  • the first heavily doped region 63 is connected to the first electrode 4.
  • the first lightly doped region 62 is located on one side of the first heavily doped region 63, and the doping concentration of the first heavily doped region 63 is greater than the doping concentration of the first lightly doped region 62.
  • the first heavily doped region 63 is connected to the first electrode 4, it is possible to ensure that the first electrode 4 has good ohmic contact with the doped passivation layer 30, so as to improve the fill factor. Furthermore, since the first lightly doped region 62 is not in contact with the first electrode 4, a non-metallic contact region is formed, and the doping concentration of the first lightly doped region 62 is low. Therefore, it is beneficial to reduce the Auger recombination of the non-metallic contact region and reduce the parasitic absorption of the doped passivation layer to ultraviolet light.
  • low-concentration phosphorus diffusion is performed on the passivation layer 3 (for example, the doping concentration is 1 to 3E+20) to form a doped passivation layer 30.
  • local laser doping is performed in the metallized area by means of a laser device to form a first heavily doped area 63.
  • the area outside the laser doping is a non-metallized area, i.e., the first lightly doped area 62.
  • a low-concentration phosphorus atom is used to dope the passivation layer in the embodiment of the present application, the problem of strong free carrier absorption of light in the long-wave band (i.e., in the wavelength range of 800nm to 1200nm) by the doped passivation layer 30 in the prior art is solved, thereby improving the battery efficiency. Furthermore, compared with the prior art due to In the case where only the phosphorus doping concentration of the Poly layer is reduced, resulting in a weakened field passivation effect and poor contact performance, a first heavily doped region and a first shallowly doped region are formed in the embodiment of the present application.
  • the doping concentration of the first heavily doped region is high, the field passivation effect of the first heavily doped region is enhanced, and the contact between the doped passivation layer and the first electrode is good, ensuring that the fill factor will not decrease.
  • the light parasitic absorption of the first shallowly doped region is weakened, and the current gain is obvious.
  • the silver paste printing line width used to form the first electrode 4 during screen printing is usually wide, resulting in high unit consumption and high cost.
  • the silver paste printing line width used to form the first electrode 4 can be appropriately narrowed to reduce the production cost.
  • a first heavily doped region and a first lightly doped region are formed in the embodiment of the present application.
  • the first heavily doped region has a high doping concentration, which ensures good contact between the doped passivation layer and the first electrode, so the screen printing line width can be appropriately narrowed.
  • the first lightly doped region has a low doping concentration, and the light parasitic absorption is relatively weak, which reduces the current loss, is conducive to improving the battery efficiency and reducing the unit consumption of metal paste.
  • the thickness of the doped passivation layer is greater than or equal to 50 nm and less than or equal to 200 nm.
  • the thickness of the doped passivation layer can be 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, 180 nm or 200 nm.
  • the solar cell provided in the present application can improve the carrier transfer efficiency, reduce or eliminate the loss of the opening voltage, and ensure excellent electrical contact performance between the electrode and the passivation layer without reducing the thickness of the doped passivation layer.
  • the width of the first heavily doped region 63 is greater than the width of the first electrode 4.
  • the width of the first heavily doped region 63 is slightly greater than the width of the first electrode 4. At this point, it is convenient for later screen alignment and printing to ensure the quality of the solar cell.
  • the semiconductor substrate 1 may be an N-type crystalline silicon body.
  • a second aluminum oxide passivation layer 80 and a second SiNx anti-reflection passivation layer 81 are sequentially formed on the light-receiving surface S1 of the semiconductor substrate 1.
  • the light-receiving surface S1 of the semiconductor substrate 1 has a selective emitter, which includes a first
  • the second electrode 9 is connected to the second heavily doped region 61 through the second SiNx anti-reflection passivation layer 81 and the second aluminum oxide passivation layer 80.
  • a first aluminum oxide passivation layer 82 and a first SiNx anti-reflection passivation layer 83 are sequentially formed on the doped passivation layer 30, and the first electrode 4 is connected to the first heavily doped region 63 through the first SiNx anti-reflection passivation layer 83 and the first aluminum oxide passivation layer 82.
  • the passivation/anti-reflection laminate structure has the following functions: it can reduce the reflection of light on the surface of the solar cell, allowing more light to enter the interior of the solar cell and be absorbed, thereby improving the photoelectric conversion efficiency; prevent the external environment from corroding the surface of the solar cell and extend the service life of the solar cell; it can reduce the recombination loss of photogenerated carriers inside the solar cell during the transmission process and improve the carrier collection efficiency, thereby improving the photoelectric conversion efficiency of the battery; it can also protect the surface of the solar cell to prevent surface defects from affecting the performance of the solar cell.
  • the embodiments of the present application further provide a solar cell assembly.
  • the method for manufacturing the solar cell includes two or more solar cells as described above, wherein the two or more solar cells are electrically connected in series, and the solar cell assembly also includes a conductive wire, which is used to electrically connect the two or more solar cells in series, and the projection of the conductive wire in the plane where the passivation layer is located partially overlaps with the projection of the first electrode in the plane where the passivation layer is located.
  • the conductive wire can be directly electrically connected to the first electrode, so that the connection point between the conductive wire and the first electrode is relatively small, thereby reducing the welding stress; at the same time, since the electrical contact performance between the first electrode and the passivation layer is good, even if the welding contact area between the conductive wire and the first electrode is small, it is still possible to ensure sufficient electrical connection between the conductive wire and the solar cell, thereby ensuring the battery efficiency of the TOPCon battery.
  • a solder joint structure may be provided on the first electrode, and the conductive wire is electrically connected to the solder joint structure by welding, wherein in a direction perpendicular to the extension direction of the first electrode, the width of the solder joint structure is greater than the width of the first electrode.
  • the present application also provides a method for manufacturing a solar cell.
  • the method for manufacturing a solar cell includes:
  • a semiconductor substrate 1 is provided, and the semiconductor substrate 1 has a light-receiving surface S1 and a backlight surface S2 opposite to each other.
  • the description of the semiconductor substrate can be referred to the first aspect, and no specific limitation is made here.
  • the semiconductor substrate 1 is subjected to a texturing process.
  • an alkali and an additive are used to perform double-sided texturing on an N-type original silicon wafer.
  • the semiconductor substrate 1 after the texturing is subjected to boron diffusion treatment.
  • a boron diffusion layer and a BSG (borosilicate glass) layer are formed on the light receiving surface S1 of the semiconductor substrate 1.
  • the boron diffusion layer and the BSG layer are locally laser doped.
  • the laser doped structure is subjected to a high temperature oxidation treatment.
  • a second heavily doped region 61 (corresponding to the region treated with laser doping) is formed on the light-receiving surface S1 of the semiconductor substrate 1 , and the remaining boron diffusion layer is a second lightly doped region 60 .
  • the backlight surface S2 of the semiconductor substrate 1 and the boron diffusion layer and the BSG layer that are extended on the side are removed, and then the backlight surface S2 of the semiconductor substrate 1 is polished by using a NaOH or KOH alkaline solution.
  • an ultra-thin dielectric layer 2 is formed on at least one of the backlight surface S2 and the light-receiving surface S1 of the semiconductor substrate 1 .
  • the thickness of the ultra-thin dielectric layer 2 is greater than or equal to 1 nm and less than or equal to 2 nm.
  • the thickness direction of the ultra-thin dielectric layer 2 is consistent with the direction from the light-receiving surface S1 to the backlight surface S2.
  • the thickness of the ultra-thin dielectric layer 2 is 1 nm, 1.4 nm, 1.6 nm, 1.9 nm or 2 nm, etc.
  • the material of the ultra-thin dielectric layer 2 includes one of silicon oxide, hafnium oxide, aluminum oxide, and silicon nitride.
  • a passivation layer 3 is formed on the ultra-thin dielectric layer 2 .
  • the method for manufacturing a solar cell further includes:
  • a low-pressure diffusion furnace is used to dope the passivation layer 3 with phosphorus, and the diffusion temperature in the doping diffusion process is greater than or equal to 800° C. and less than or equal to 830° C.
  • the diffusion temperature in the doping diffusion process is greater than or equal to 800° C. and less than or equal to 830° C.
  • the push-in temperature is greater than or equal to 850°C and less than or equal to 900°C.
  • a post-diffusion deposition process is performed on the doped passivation layer 30 to form a second doping source layer on the doped passivation layer 30;
  • a PSG (phosphorosilicate glass) layer is formed on the doped passivation layer 30.
  • the diffusion temperature in the post-diffusion deposition process is greater than or equal to 820° C. and less than or equal to 850° C. For example, 820° C., 825° C., 830° C., 840° C., or 850° C.
  • the second doping source layer is regionally processed by laser irradiation process to form a first heavily doped region 63 in the doped passivation layer 30; the remaining doped passivation layer 30 is the first lightly doped region 62;
  • laser is used to drive phosphorus atoms in the phosphorus-rich PSG layer into the doped passivation layer 30 to form a first heavily doped region in the doped passivation layer 30 .
  • the first heavily doped region 63 is connected to the first electrode 4 correspondingly; the doping concentration of the first heavily doped region 63 is greater than the doping concentration of the first lightly doped region 62 .
  • the first heavily doped region 63 is connected to the first electrode 4, it is possible to ensure that the first electrode 4 has good ohmic contact with the doped passivation layer 30, so as to improve the fill factor. Furthermore, since the first lightly doped region 62 is not in contact with the first electrode 4, a non-metallic contact region is formed, and the doping concentration of the first lightly doped region 62 is low. Therefore, it is beneficial to reduce the Auger recombination of the non-metallic contact region and reduce the parasitic absorption of ultraviolet light by the doped passivation layer.
  • the light-receiving surface S1 of the semiconductor substrate 1 and the phosphorus diffusion layer and PSG layer around the side are removed, and then the doped passivation layer 30 around the light-receiving surface S1 and the BSG layer of the light-receiving surface S1 and the PSG layer of the backlight surface S2 are removed;
  • a first aluminum oxide passivation layer 82 is formed on the doped passivation layer 30 ;
  • a second aluminum oxide passivation layer 80 is formed on the light receiving surface S1 of the semiconductor substrate 1 ;
  • a first SiNx anti-reflection passivation layer 83 is formed on the first aluminum oxide passivation layer 82; and a second SiNx anti-reflection passivation layer 81 is formed on the second aluminum oxide passivation layer 80;
  • the first electrode 4 and the second electrode 9 are formed.
  • the first electrode 4 on the backlight surface S2 is connected to the first heavily doped region 63 through the first SiNx anti-reflection passivation layer 83 and the first aluminum oxide passivation layer 82.
  • the second electrode 9 on the light-receiving surface S1 is connected to the second heavily doped region 61 through the second SiNx anti-reflection passivation layer 81 and the second aluminum oxide passivation layer 80.
  • Metal crystals are formed in the passivation layer 3 , wherein the metal crystals include a first metal crystal 50 , one end surface of the first metal crystal 50 abuts against the ultra-thin dielectric layer 2 , and the other end surface of the first metal crystal 50 is connected to the first electrode 4 .
  • the carrier transmission efficiency can be improved without thinning the passivation layer 3, the loss of the opening voltage can be reduced or eliminated, and the excellent electrical contact performance between the electrode and the passivation layer can be ensured.
  • one end face of the first metal crystal 50 is in contact with the ultra-thin dielectric layer 2, and the other end face of the first metal crystal 50 is connected to the first electrode 4, a metal-ultra-thin dielectric-semiconductor structure is formed. Since the first metal crystal 50 is located in the passivation layer 3, the first metal crystal 50 is in full contact with the passivation layer 3.
  • the filling factor can be optimized by controlling the ratio of the first metal crystal 50, and the opening voltage and the filling factor can be balanced. Further, under the action of the first metal crystal 50, it is beneficial for the carrier to move to the first electrode 4, which speeds up the transmission rate of the carrier, thereby shortening the time required for the carrier to pass through the passivation layer 3.
  • the first metal crystal 50 does not pass through the ultra-thin dielectric layer 2 to enter the semiconductor substrate 1, at this time, it can not only ensure that the ultra-thin dielectric layer 2 is not damaged, but also ensure that the function of the ultra-thin dielectric layer 2 is not affected. That is, good chemical passivation and tunneling effect of the ultra-thin dielectric layer are ensured.
  • the impact on the opening voltage can be reduced to avoid damage to the semiconductor substrate 1, thereby ensuring that the function of the semiconductor substrate 1 is not affected, and further ensuring the performance of the solar cell.
  • the first metal crystal abuts against the ultra-thin dielectric layer without destroying the structure of the ultra-thin dielectric layer, thus ensuring good chemical passivation and tunneling effect of the ultra-thin dielectric layer.
  • the ultra-thin dielectric layer acts as a tunneling transmission layer for majority carriers, and can transmit majority carriers in the semiconductor substrate through the ultra-thin dielectric layer.
  • the first metal crystal takes on the role of quickly transmitting majority carriers through the ultra-thin dielectric layer to the first electrode to ensure a higher fill factor.
  • the good majority carrier transmission efficiency of the backlight passivation structure can obtain a smaller contact resistivity and series resistance, thereby ensuring a higher battery efficiency.
  • the ratio of the number of the first metal crystals to the total number of the metal crystals is The value is greater than or equal to 2% and less than or equal to 20%.
  • the ratio may be 2%, 5%, 8%, 12%, 15%, 17%, 18% or 20%. At this time, the influence of the tunneling-polycrystalline carrier tunneling effect due to the excessive number of the first metal crystals can be avoided.
  • the width of the first metal crystal 50 gradually decreases.
  • the width of the first metal crystal gradually decreases along the direction from the first electrode to the passivation layer, which reduces the corrosion of the passivation layer and the semiconductor substrate, and reduces the metal recombination at the interface of the metal-ultra-thin dielectric layer. Furthermore, the width of the first metal crystal gradually increases along the direction from the passivation layer to the first electrode, which increases the contact area between the first metal crystal and the first electrode, which is beneficial to improve the transmission efficiency of the first metal crystal transporting the majority carriers from the light-receiving surface to the backlight surface to the first electrode.
  • the first metal crystals 50 are approximately trapezoidal in shape.
  • one end surface of the first metal crystal 50 abuts against the ultra-thin dielectric layer 2, and the other end surface of the first metal crystal 50 penetrates into the first electrode 4, and the specific depth can be set according to actual conditions.
  • the metal crystal 5 further includes: a second metal crystal 51.
  • the second metal crystal 51 is connected to the first electrode 4 and is spaced apart from the first metal crystal 50.
  • the thickness of the second metal crystal 51 is less than the thickness of the passivation layer 3, and the thickness direction of the second metal crystal 51 and the thickness direction of the passivation layer 3 are both consistent with the direction from the backlight surface S2 to the light receiving surface S1. It should be understood that one end face of the second metal crystal 51 may also penetrate into the first electrode 4, wherein the size of the second metal crystal 51 penetrating into the first electrode 4 and the thickness of the second metal crystal 51 are set according to actual conditions and are not specifically limited here.
  • the second metal crystal 51 is less than the thickness of the passivation layer 3, the second metal crystal 51 can be avoided. The crystals 51 damage the ultra-thin dielectric layer 2 and the semiconductor substrate 1 to ensure the performance of the solar cell.
  • the plurality of second metal crystals are distributed at intervals. And/or, the ratio of the number of second metal crystals to the total number of metal crystals is greater than or equal to 50% and less than or equal to 90%. For example, the ratio may be 50%, 58%, 62%, 75%, 82% or 90%, etc.
  • the second metal crystal is less than the thickness of the passivation layer, the second metal crystal can be prevented from damaging the ultra-thin dielectric layer and the semiconductor substrate to ensure the performance of the solar cell.
  • the metal crystal 5 further includes: a third metal crystal 52.
  • the third metal crystal 52 is spaced apart from the first electrode 4, the ultra-thin dielectric layer 2, and the second metal crystal 51. That is, the third metal crystal 52 is neither connected to the first electrode 4 nor to the ultra-thin dielectric layer 2.
  • the carriers it is more conducive for the carriers to move to the first electrode 4, further accelerating the carrier transmission rate, and further shortening the time required for the carriers to pass through the passivation layer 3, so as to ensure the battery efficiency of the TOPCon battery. Furthermore, since the third metal crystals 52 and the ultra-thin dielectric layer 2 are spaced apart, the third metal crystals 52 can be prevented from damaging the ultra-thin dielectric layer 2 and the semiconductor substrate 1, so as to ensure the performance of the solar cell.
  • a plurality of third metal crystals 52 are discretely distributed in the passivation layer 3. And/or, along the direction from the first electrode 4 to the passivation layer 3, the spacing between the third metal crystal 52 and the first electrode 4 is smaller than the spacing between the third metal crystal 52 and the ultra-thin dielectric layer 2. In the embodiment of the present application, the spacing between the third metal crystal 52 and the first electrode 4 is smaller than half the thickness of the passivation layer 3. And/or, the ratio of the number of second metal crystals 51 to the total number of metal crystals is less than or equal to 5%.
  • the ratio of the average volume of the third metal crystals 52 to the average volume of the second metal crystals 51 is less than or equal to 10%.
  • the third metal crystal 52 with a smaller size is easy to be separated from the first electrode.
  • the third metal crystals are not expected to appear, but they are inevitable during the manufacturing process. Therefore, it is necessary to control the average volume and number of the third metal crystals within the above value range to reduce the impact of the third metal crystals on the efficiency of the solar cell.
  • the first metal crystal 50 has the largest size compared to the second metal crystal 51 and the third metal crystal 52. Further, the first metal crystal 50, the second metal crystal 51 and the third metal crystal 52 are all distributed at intervals.

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Abstract

本申请公开了一种太阳能电池、太阳能电池组件和太阳能电池的制作方法，以保证第一电极与钝化层之间的良好欧姆接触，提高载流子传输效率，减弱光寄生吸收，进而确保TOPCon电池的电池效率。太阳能电池包括：半导体基底、超薄介质层、钝化层、第一电极和金属晶体。半导体基底具有相对的受光面和背光面，超薄介质层位于半导体基底的背光面和受光面中的至少一面上，钝化层位于超薄介质层上，第一电极位于钝化层上，金属晶体位于钝化层内。其中，金属晶体包括第一金属晶体，第一金属晶体的一端面与超薄介质层抵接，第一金属晶体的另一端面与第一电极连接。

Description

一种太阳能电池、太阳能电池组件和太阳能电池的制作方法
相关申请的交叉引用
本申请要求于2023年10月18日提交的申请号为2023113557296的中国申请的优先权，该中国申请的内容通过引用并入本文。
技术领域
本申请涉及太阳能电池技术领域，尤其涉及一种太阳能电池、太阳能电池组件和太阳能电池的制作方法。
背景技术
太阳能电池是利用太阳能的一种装置，通过光电效应或者光化学效应直接把光能转化成电能。上述太阳能电池包括隧穿氧化钝化接触太阳能电池(Tunnel Oxide Passivated Contact solar cell，简称为TOPCon)。
TOPCon电池的掺杂钝化层沉积有较厚的Poly层，导致载流子穿过钝化层所需的时间较长，光寄生吸收严重，进而影响TOPCon电池的电池效率。
申请内容
本申请的目的在于提供一种太阳能电池、太阳能电池组件和太阳能电池的制作方法，用于提高载流子传输效率，减弱光寄生吸收，以确保TOPCon电池的电池效率。
为了实现上述目的，第一方面，本申请提供了一种太阳能电池。该太阳能电池包括：半导体基底、超薄介质层、钝化层(在本领域中也被称为掺杂半导体层)、第一电极和金属晶体。半导体基底具有相对的受光面和背光面，超薄介质层位于半导体基底的背光面和受光面中的至少一面上，钝化层位于超薄介质层上，第一电极位于钝化层上，金属晶体位于钝化层内。其中，金属晶体包括第一金属晶体，第一金属晶体的一端面与超薄介质层抵接，第一金属晶体的另一端面与第一电极连接。
与现有技术相比，本申请提供的太阳能电池可以在不减薄钝化层的基础上，提高载流子传输效率，减小或消除开压的损失，并确保电极与钝化层之间优异的电接触性能。进一步地，由于第一金属晶体的一端面与超薄介质层抵接，第一金属晶体的另一端面与第一电极连接，形成了金属-超薄介质-半导体的结构。又由于第一金属晶体位于钝化层内，第一金属晶体与钝化层充分接触。基于此，通过控制第一金属晶体的比率可以优化填充因子，平衡开压和填充因子。再进一步地，在第一金属晶体的作用下，有利于载流子移动到第一电极，加快了载流子的传输速率，进而缩短了载流子穿过钝化层所需的时间。此外，由于第一金属晶体并未穿过超薄介质层进入半导体基底，此时，不仅可以确保超薄介质层不被破坏，以确保超薄介质层的功能不受影响。即，保证了超薄介质层良好的化学钝化和隧穿效应。同时，还可以减小对开压的影响，以避免半导体基底被破坏，以确保半导体基底的功能不受影响，进而确保太阳能电池的性能。
综上所述，第一金属晶体与超薄介质层抵接，未破坏超薄介质层结构，因此保证了超薄介质层良好的化学钝化和隧穿效应。超薄介质层作为多数载流子的隧穿传输层，可以传输半导体基底中的多数载流子通过超薄介质层。紧接着，第一金属晶体承担着快速传输通过超薄介质层的多数载流子到第一电极的作用，以确保获得更高的填充因子，钝化结构良好的多数载流子传输效率可以获得较小的接触电阻率和串联电阻，从而确保获得更高的电池效率。
在一种实现方式中，在背光面和受光面中的至少一面上局部地设置有钝化层。
在一种实现方式中，第一金属晶体的数量与金属晶体的总数量的比值大于或等于2％，且小于或等于20％。
采用上述技术方案的情况下，可以避免因第一金属晶体的数量过多影响隧穿-多晶的载流子隧穿效果。
在一种实现方式中，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐减小。
采用上述技术方案的情况下，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐减小，减小了对钝化层和半导体基底的腐蚀，减小了金属-超薄介质层界面的金属复合。进一步地，沿钝化层向第一电极的方向，第一金属晶体的宽度逐渐增加，增大了第一金属晶体与第一电极的接触面积，有利于提升第一金属晶体输运的多数载流子到第一电极的传输效率。
在一种实现方式中，金属晶体还包括：第二金属晶体。第二金属晶体与第一电极连接，且与第一金属晶体间隔分布。第二金属晶体的厚度小于钝化层的厚度，第二金属晶体的厚度方向和钝化层的厚度方向均与背光面至受光面的方向一致。
采用上述技术方案的情况下，不仅更有利于载流子移动到第一电极，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层所需的时间，以确保TOPCon电池的电池效率。同时，还可以降低第一电极和钝化层之间的接触电阻。进一步地，由于第二金属晶体的厚度小于钝化层的厚度，因此可以避免第二金属晶体损伤超薄介质层和半导体基底，以确保太阳能电池的性能。
在一种实现方式中，多个第二金属晶体间隔分布。和/或，第二金属晶体的数量与金属晶体的总数量的比值大于或等于50％，且小于或等于90％。
在一种实现方式中，金属晶体还包括：第三金属晶体。第三金属晶体与第一电极、超薄介质层和第二金属晶体均间隔分布。
在一种实现方式中，多个第三金属晶体离散分布在钝化层内；和/或，沿钝化层至第一电极的方向，第三金属晶体与第一电极之间的间距小于第三金属晶体与超薄介质层之间的间距；和/或，第二金属晶体的数量与金属晶体的总数量的比值小于或等于5％。和/或，第三金属晶体的平均体积和第二金属晶体的平均体积的比值小于或等于10％。
采用上述技术方案的情况下，较小尺寸的第三金属晶体易于脱离第一电极主体，在实际制作过程中，上述第三金属晶体是不希望出现的，但是在制作时又不可避免的会出现。因此，需要控制第三金属晶体的平均体积和数量在上述 取值范围内，以降低第三金属晶体对太阳能电池效率产生的影响。
在一种实现方式中，钝化层为掺杂钝化层时，掺杂钝化层包括：第一重掺杂区域和第一浅掺杂区域。第一重掺杂区域与第一电极对应连接。第一浅掺杂区域位于第一重掺杂区域一侧，第一重掺杂区域的掺杂浓度大于第一浅掺杂区域的掺杂浓度。
采用上述技术方案的情况下，由于第一重掺杂区域与第一电极对应连接，因此可以保证第一电极与掺杂钝化层之间具有良好的欧姆接触，以提高填充因子。进一步地，由于第一浅掺杂区域不与第一电极接触，形成了非金属接触区，并且第一浅掺杂区域的掺杂浓度较低。因此，有利于降低非金属接触区的俄歇复合以及降低掺杂钝化层对紫外光的寄生吸收。此外，相比于现有技术中，为了保证掺杂钝化层与第一电极之间具有良好的欧姆接触，通常情况下，丝网印刷时用于形成第一电极的银浆印刷线宽较宽，导致单耗较高，成本高。但是，在本申请中，通过使第一电极与第一重掺杂区域连接，保证了第一电极与掺杂钝化层之间具有良好的欧姆接触。因此，可以适当的收窄用于形成第一电极的银浆印刷线宽，以降低制作成本。
在一种实现方式中，掺杂钝化层的厚度大于或等于50nm，且小于或等于200nm。
采用上述技术方案的情况下，相比于现有技术，在本申请的实现方式中，可以在掺杂钝化层的厚度未减薄的情况下，提高载流子传输效率，减小或消除开压的损失，并确保电极与钝化层之间优异的电接触性能。
在一种实现方式中，超薄介质层的厚度大于或等于1nm，且小于或等于2nm。超薄介质层的厚度方向与受光面至背光面的方向一致。和/或，超薄介质层的材质包括氧化硅、氧化铪、氧化铝、氮化硅中的一种。
第二方面，本申请还提供了一种太阳能电池组件，该太阳能电池组件包括两个或更多个前文所述的太阳能电池，其中，两个或更多个太阳能电池之间以串联的方式电联接，并且太阳能电池组件还包括导电线，导电线用于将两个或 更多个太阳能电池以串联的方式电联接，导电线在钝化层所在的平面内的投影与第一电极在钝化层所在的平面内的投影部分重叠。
第三方面，本申请还提供了一种太阳能电池的制作方法。该太阳能电池的制作方法包括：
首先，提供一半导体基底，半导体基底具有相对的受光面和背光面。接下来，在半导体基底的背光面和受光面中的至少一面上形成超薄介质层；接下来，在超薄介质层上形成钝化层；接下来，在上形成第一电极；在钝化层内形成有金属晶体。其中，金属晶体包括第一金属晶体，第一金属晶体的一端面与超薄介质层抵接，第一金属晶体的另一端面与第一电极连接。
与现有技术相比，在本申请提供的太阳能电池的制作方法中，可以在不减薄钝化层的情况下，提高载流子传输效率，减小或消除开压的损失，并确保电极与钝化层之间优异的电接触性能。进一步地，由于第一金属晶体的一端面与超薄介质层抵接，第一金属晶体的另一端面与第一电极连接，形成了金属-超薄介质-半导体的结构。又由于第一金属晶体位于钝化层内，第一金属晶体与钝化层充分接触。基于此，通过控制第一金属晶体的比率可以优化填充因子，平衡开压和填充因子。再进一步地，在第一金属晶体的作用下，有利于载流子移动到第一电极，加快了载流子的传输速率，进而缩短了载流子穿过钝化层所需的时间。此外，由于第一金属晶体并未穿过超薄介质层进入半导体基底，此时，不仅可以确保超薄介质层不被破坏，以确保超薄介质层的功能不受影响。即，保证了超薄介质层良好的化学钝化和隧穿效应。同时，还可以减小对开压的影响，以避免半导体基底被破坏，以确保半导体基底的功能不受影响，进而确保太阳能电池的性能。
综上所述，第一金属晶体与超薄介质层抵接，未破坏超薄介质层结构，因此保证了超薄介质层良好的化学钝化和隧穿效应。超薄介质层作为多数载流子的隧穿传输层，可以传输半导体基底中的多数载流子通过超薄介质层。紧接着，第一金属晶体承担着快速传输通过超薄介质层的多数载流子到第一电极的作用， 以确保获得更高的填充因子，钝化结构良好的多数载流子传输效率可以获得较小的接触电阻率和串联电阻，从而确保获得更高的电池效率。
在一种实现方式中，第一金属晶体的数量与金属晶体的总数量的比值大于或等于2％，且小于或等于20％。
采用上述技术方案的情况下，可以避免因第一金属晶体的数量过多影响隧穿-多晶的载流子隧穿效果。
在一种实现方式中，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐减小。
采用上述技术方案的情况下，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐减小，减小了对钝化层和半导体基底的腐蚀，减小了金属-超薄介质层界面的金属复合。进一步地，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐增加，增大了第一金属晶体与第一电极的接触面积，有利于提升第一金属晶体输运的多数载流子到第一电极的传输效率。
在一种实现方式中，金属晶体还包括：第二金属晶体。第二金属晶体与第一电极连接，且与第一金属晶体间隔分布。第二金属晶体的厚度小于钝化层的厚度，第二金属晶体的厚度方向和钝化层的厚度方向均与背光面至受光面的方向一致。
采用上述技术方案的情况下，不仅更有利于载流子移动到第一电极，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层所需的时间，以确保TOPCon电池的电池效率。同时，还可以降低第一电极和钝化层之间的接触电阻。进一步地，由于第二金属晶体的厚度小于钝化层的厚度，因此可以避免第二金属晶体损伤超薄介质层和半导体基底，以确保太阳能电池的性能。
在一种实现方式中，多个第二金属晶体间隔分布。和/或，第二金属晶体的数量与金属晶体的总数量的比值大于或等于50％，且小于或等于90％。
在一种实现方式中，金属晶体还包括：第三金属晶体。第三金属晶体与第一电极、超薄介质层和第二金属晶体均间隔分布。
在一种实现方式中，多个第三金属晶体离散分布在钝化层内；和/或，沿第一电极向钝化层的方向，第三金属晶体与第一电极之间的间距小于第三金属晶体与超薄介质层之间的间距；和/或，第二金属晶体的数量与金属晶体的总数量的比值小于或等于5％。和/或，第三金属晶体的平均体积和第二金属晶体的平均体积的比值小于或等于10％。
采用上述技术方案的情况下，较小尺寸的第三金属晶体易于脱离第一电极主体，在实际制作过程中，上述第三金属晶体是不希望出现的，但是在制作时又不可避免的会出现。因此，需要控制第三金属晶体的平均体积和数量在上述取值范围内，以降低第三金属晶体对太阳能电池效率产生的影响。
在一种实现方式中，在超薄介质层上形成钝化层后，太阳能电池的制作方法还包括：
对钝化层进行掺杂扩散处理，以形成掺杂钝化层；
对掺杂钝化层进行后扩散沉积处理，以在掺杂钝化层上形成第二掺杂源层；
采用激光照射工艺对第二掺杂源层进行区域性处理，以在掺杂钝化层内形成第一重掺杂区域；剩余掺杂钝化层为第一浅掺杂区域；
其中，第一重掺杂区域与第一电极对应连接；第一重掺杂区域的掺杂浓度大于第一浅掺杂区域的掺杂浓度。
采用上述技术方案的情况下，由于第一重掺杂区域与第一电极对应连接，因此可以保证第一电极与掺杂钝化层之间具有良好的欧姆接触，以提高填充因子。进一步地，由于第一浅掺杂区域不与第一电极接触，形成了非金属接触区，并且第一浅掺杂区域的掺杂浓度较低。因此，有利于降低非金属接触区的俄歇复合以及降低掺杂钝化层对紫外光的寄生吸收。
在一种实现方式中，掺杂扩散处理中扩散温度大于或等于800℃，且小于或等于830℃。后扩散沉积处理中扩散温度大于或等于820℃，且小于或等于850℃。
在一种实现方式中，上述超薄介质层的厚度大于或等于1nm，且小于或等于2nm。超薄介质层的厚度方向与受光面至背光面的方向一致。和/或，超薄介质层的材质包括氧化硅、氧化铪、氧化铝、氮化硅中的一种。
附图说明
此处所说明的附图用来提供对本申请的进一步理解，构成本申请的一部分，本申请的示意性实施例及其说明用于解释本申请，并不构成对本申请的不当限定。在附图中：
图1为本申请实施例中太阳能电池的结构示意图一；
图2为本申请实施例中图1的部分结构的放大示意图；
图3为本申请实施例中太阳能电池的结构示意图二。
附图标记：
1-半导体基底，          S1-受光面，              S2-背光面，
2-超薄介质层，          3-钝化层，               30-掺杂钝化层，
4-第一电极，            5-金属晶体，             50-第一金属晶体，
51-第二金属晶体，       52-第三金属晶体，        60-第二浅掺杂区域，
61-第二重掺杂区域，     62-第一浅掺杂区域，      63-第一重掺杂区域，
64-发射极，                           70-第一钝化/减反射叠层结构，
71-第二钝化/减反射叠层结构，           80-第二氧化铝钝化层，
81-第二SiNx减反射钝化层，             82-第一氧化铝钝化层，
83-第一SiNx减反射钝化层，             9-第二电极。
具体实施方式
为了使本申请所要解决的技术问题、技术方案及有益效果更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。
需要说明的是，当元件被称为“固定于”或“设置于”另一个元件，它可 以直接在另一个元件上或者间接在该另一个元件上。当一个元件被称为是“连接于”另一个元件，它可以是直接连接到另一个元件或间接连接至该另一个元件上。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。“若干”的含义是一个或一个以上，除非另有明确具体的限定。
在本申请的描述中，需要理解的是，术语“上”、“下”、“前”、“后”、“左”、“右”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。
在本申请的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
在现有的TOPCon电池技术中，影响其电池效率提升的众多因素里，一个重要的因素是电池掺杂钝化层存在较强的光寄生吸收。具体地，由于TOPCon电池的掺杂钝化层沉积有较厚的Poly层，导致载流子穿过钝化层所需的时间较长，光寄生吸收严重。进一步地，N型TOPCon电池Poly层磷原子掺杂浓度在3～6*E20左右且是均匀掺杂，高浓度磷原子掺杂的Poly层对长波段(即800nm～1200nm波长范围)的光会产生很强的自由载流子吸收现象，影响电池效率。另外，在TOPCon电池结构中，电极一般使用含银浆料进行烧结形成，电 极与Poly层的接触不良会降低填充因子。
目前，多数研究通过减薄Poly层厚度，缩短载流子穿过掺杂Poly层所需的时间或低浓度掺杂Poly来减弱光寄生吸收，从而达到提升电池效率的目的。但是，实验验证Poly层厚度减薄虽然可以起到降低紫外光寄生效应，提高光电流的作用，但开压损失明显。此外，降低Poly中磷掺杂浓度会导致场钝化效应变弱以及接触性能变差，导致填充因子急剧下降。
为了解决上述技术问题，第一方面，本申请实施例提供了一种太阳能电池。
参见图1和图2，该太阳能电池包括：半导体基底1、超薄介质层2、钝化层3、第一电极4和金属晶体5。半导体基底1具有相对的受光面S1和背光面S2，超薄介质层2位于半导体基底1的背光面S2和受光面S1中的至少一面上，钝化层3位于超薄介质层2上，第一电极4位于钝化层3上，金属晶体5位于钝化层3内。金属晶体5包括第一金属晶体50，其中，第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面与第一电极4连接。需要说明的是，虽然在本申请示出的实施例中，钝化层3仅示出为设置在背光面S2处的超薄介质层2上，但是应当理解的是，半导体基底1的受光面S1也可以设置相应的超薄介质层2和钝化层3。
上述半导体基底可以为硅衬底，在本实施例中为单晶硅衬底，在其他实施例中可以为多晶硅衬底。
可选地，可以在背光面S2和受光面S1中的至少一面上局部地设置有钝化层3。例如，可以在背光面S2上局部地设置有钝化层3。当然，也可以在受光面S1上局部地设置有钝化层3，或者在背光面S2和受光面S1二者上均局部地设置有钝化层3。可选地，钝化层3设置在超薄介质层2上。
作为一种可能的实现方式，第一电极由金属浆料制成，例如，主要采用银浆料烧结形成。具体地，首先通过丝网印刷，激光转印等手段将金属浆料印刷到指定位置，之后经过烧结，形成电极金属材料与钝化层的优异接触。
在实际制作过程，银浆料包括银金属成分、玻璃料以及其他添加剂和溶剂。 在印刷完第一电极图形后，经过烘干除去部分有机部分，之后进行烧结，烧结温度大于或等于700℃，且小于或等于800℃，优选740℃。烧结之后，绝大多数银电极材料分布在钝化层的表面，形成第一电极。
金属晶体的材质可以根据实际情况进行选择。示例性的，金属晶体的材质可以和第一电极的材质相同，例如银。
作为一种可能的实现方式，太阳能电池可以是隧穿氧化钝化接触太阳能电池。下面以隧穿氧化钝化接触太阳能电池为例进行描述，应理解，以下描述仅用于理解，不用于具体限定。参见图1和图2，与现有技术相比，本申请实施例提供的太阳能电池可以在不减薄钝化层3的情况下，提高载流子传输效率，减小或消除开压的损失，并确保电极与钝化层之间优异的电接触性能。进一步地，由于第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面与第一电极4连接，形成了金属-超薄介质-半导体的结构。又由于第一金属晶体50位于钝化层3内，第一金属晶体50与钝化层3充分接触。基于此，通过控制第一金属晶体50的比率可以优化填充因子，平衡开压和填充因子。再进一步地，在第一金属晶体50的作用下，有利于载流子移动到第一电极4，加快了载流子的传输速率，进而缩短了载流子穿过钝化层3所需的时间。基于此，可以提高载流子传输效率，减弱光寄生吸收，以确保TOPCon电池的电池效率。
此外，由于第一金属晶体50并未穿过超薄介质层2进入半导体基底1，此时，不仅可以确保超薄介质层2不被破坏，以确保超薄介质层2的功能不受影响。即，保证了超薄介质层良好的化学钝化和隧穿效应。同时，还可以减小对开压的影响，以避免半导体基底1被破坏，以确保半导体基底1的功能不受影响，进而确保太阳能电池的性能。
综上所述，第一金属晶体与超薄介质层抵接，未破坏超薄介质层结构，因此保证了超薄介质层良好的化学钝化和隧穿效应。超薄介质层作为多数载流子的隧穿传输层，可以传输半导体基底中的多数载流子通过超薄介质层。紧接着，第一金属晶体承担着快速传输通过超薄介质层的多数载流子到第一电极的作用， 以确保获得更高的填充因子，钝化结构良好的多数载流子传输效率可以获得较小的接触电阻率和串联电阻，从而确保获得更高的电池效率。
作为一种可能的实现方式，钝化层的结构可以是多晶、非晶或微晶等。在本申请实施例中，钝化层的结构为多晶结构，且晶化率在98％以上。另外，当钝化层为多晶硅钝化层时，多晶硅钝化层的厚度大于或等于45nm，且小于或等于200nm，多晶硅钝化层的厚度方向与背光面至受光面的方向一致。例如，厚度可以是45nm、50nm、80nm、100nm、120nm、150nm或200nm等。
作为一种可能的实现方式，超薄介质层2的厚度大于或等于1nm，且小于或等于2nm。超薄介质层2的厚度方向与受光面S1至背光面S2的方向一致。例如，1nm、1.2nm、1.5nm、1.7nm、1.85nm或2nm等。和/或，超薄介质层2的材质包括氧化硅、氧化铪、氧化铝、氮化硅中的一种。
在本申请实施例中，超薄介质层为隧穿氧化层。
作为一种可能的实现方式，参见图2，第一金属晶体50的数量与金属晶体5的总数量的比值大于或等于2％，且小于或等于20％。例如，比值可以是2％、5％、8％、12％、15％、17％、18％或20％等。此时，可以避免因第一金属晶体的数量过多影响隧穿-多晶的载流子隧穿效果。
参见图1和图2，第一金属晶体50并未烧穿超薄介质层2进入半导体基底1其原因可能是：银浆料中含有相当数量的金属银和氧化物玻璃料成分(例如氧化铅)，玻璃料成分腐蚀钝化/减反射层后，金属银和玻璃料进入钝化层3。之后随着烧结的继续进行，金属银及其附着的氧化物进入到隧穿层的界面，鉴于超薄介质层2仅有几个纳米的尺度，且硅衬底为致密的单晶结构，金属银无法进一步穿过隧穿层进入硅衬底。或者，伴随银的氧化物可能与硅衬底的界面发生氧化反应，在银晶体与硅衬底之间形成氧化硅层。
作为一种可能的实现方式，参见图2，沿第一电极4向钝化层3的方向，第一金属晶体50的宽度逐渐减小。
采用上述技术方案的情况下，沿第一电极向钝化层的方向，第一金属晶体 的宽度逐渐减小，减小了对钝化层和半导体基底的腐蚀，减小了金属-超薄介质层界面的金属复合。进一步地，沿钝化层向第一电极的方向，第一金属晶体的宽度逐渐增加，增大了第一金属晶体与第一电极的接触面积，有利于提升第一金属晶体输运沿受光面到背光面的多数载流子到第一电极的传输效率。
示例性的，沿第一电极4向钝化层3的方向，第一金属晶体50呈大致梯形的形态。
作为一种可选的实现方式，第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面深入第一电极4内，具体深入的尺寸可以根据实际情况进行设置。
作为一种可能的实现方式，参见图2，金属晶体5还包括：第二金属晶体51。第二金属晶体51与第一电极4连接，且与第一金属晶体50间隔分布。第二金属晶体51的厚度小于钝化层3的厚度，第二金属晶体51的厚度方向和钝化层3的厚度方向均与背光面S2至受光面S1的方向一致。应理解，第二金属晶体51的一端面也可以深入第一电极4内，其中，第二金属晶体51深入第一电极4内的尺寸以及第二金属晶体51的厚度根据实际情况进行设置，在此不做具体限定。
此时，不仅更有利于载流子移动到第一电极4，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层3所需的时间，以确保TOPCon电池的电池效率。同时，还可以降低第一电极4和钝化层3之间的接触电阻。进一步地，由于第二金属晶体51的厚度小于钝化层3的厚度，因此可以避免第二金属晶体51损伤超薄介质层2和半导体基底1，以确保太阳能电池的性能。
在一种可选方式中，参见图2，多个第二金属晶体51间隔分布。和/或，第二金属晶体51的数量与金属晶体的总数量的比值大于或等于50％，且小于或等于90％。例如，比值可以是50％、58％、62％、75％、82％或90％等。
采用上述技术方案的情况下，不仅更有利于载流子移动到第一电极，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层所需的时间，以 确保TOPCon电池的电池效率。同时，还可以降低第一电极和钝化层之间的接触电阻。进一步地，由于第二金属晶体的厚度小于钝化层的厚度，因此可以避免第二金属晶体损伤超薄介质层和半导体基底，以确保太阳能电池的性能。
在一种可选方式中，参见图2，金属晶体5还包括：第三金属晶体52。第三金属晶体52与第一电极4、超薄介质层2和第二金属晶体51均间隔分布。即第三金属晶体52即不与第一电极4连接，也不与超薄介质层2连接。
此时，更有利于载流子移动到第一电极4，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层3所需的时间，以确保TOPCon电池的电池效率。进一步地，由于第三金属晶体52与超薄介质层2间隔分布，因此可以避免第三金属晶体52损伤超薄介质层2和半导体基底1，以确保太阳能电池的性能。
在一种可选的方式中，参见图2，多个第三金属晶体52离散分布在钝化层3内。和/或，沿第一电极4向钝化层3的方向，第三金属晶体52与第一电极4之间的间距小于第三金属晶体52与超薄介质层2之间的间距。在本申请实施例中，第三金属晶体52与第一电极4之间的间距小于钝化层3厚度的一半。和/或，第二金属晶体51的数量与金属晶体的总数量的比值小于或等于5％。
在一种可选方式中，参见图2，由于较小尺寸的金属晶体易于脱离第一电极4主体，但是较难向更深入钝化层3的方向生长和延伸。因此，第三金属晶体52的平均体积和第二金属晶体51的平均体积的比值小于或等于10％。
采用上述技术方案的情况下，较小尺寸的第三金属晶体52易于脱离第一电极4主体，在实际制作过程中，上述第三金属晶体是不希望出现的，但是在制作时又不可避免的会出现。因此，需要控制第三金属晶体的平均体积和数量在上述取值范围内，以降低第三金属晶体对太阳能电池效率产生的影响。
结合前文描述，相比于第二金属晶体51和第三金属晶体52，第一金属晶体50的尺寸最大。进一步地，第一金属晶体50、第二金属晶体51和第三金属晶体52均间隔分布。
作为一种可能的实现方式，参见图1，太阳能电池的受光面S1具有发射极64，其通过与半导体基底1具有相反的掺杂类型获得。发射极64可以具有单一的掺杂区域，也可以具有选择性发射极结构，即同时包括第二浅掺杂区域60，以及与第二电极9接触的第二重掺杂区域61。第二重掺杂区域61的掺杂浓度大于第二浅掺杂区域60的掺杂浓度。
作为一种可能的实现方式，沿着远离半导体基底的方向，钝化层3上形成有第一钝化/减反射叠层结构70，第一电极4穿过第一钝化/减反射叠层结构70与钝化层3连接。可选地，如图1所示，在半导体基底1的受光面S1处还形成有第二钝化/减反射叠层结构71，第二电极9穿过第二钝化/减反射叠层结构71与第二重掺杂区域61连接。
作为一种可能的实现方式，参见图3，钝化层为掺杂钝化层30时，掺杂钝化层30包括：第一重掺杂区域63和第一浅掺杂区域62。第一重掺杂区域63与第一电极4对应连接。第一浅掺杂区域62位于第一重掺杂区域63一侧，第一重掺杂区域63的掺杂浓度大于第一浅掺杂区域62的掺杂浓度。
由于第一重掺杂区域63与第一电极4对应连接，因此可以保证第一电极4与掺杂钝化层30之间具有良好的欧姆接触，以提高填充因子。进一步地，由于第一浅掺杂区域62不与第一电极4接触，形成了非金属接触区，并且第一浅掺杂区域62的掺杂浓度较低。因此，有利于降低非金属接触区的俄歇复合以及降低掺杂钝化层对紫外光的寄生吸收。
示例性的，在实际制作过程，对钝化层3进行低浓度磷扩散(例如，掺杂浓度为1～3E+20)，以形成掺杂钝化层30。接着，通过激光设备在金属化区域进行局部激光掺杂，以形成第一重掺杂区域63。激光掺杂以外的区域为非金属化区域，即第一浅掺杂区域62。此时，解决了现有技术中Poly层均匀掺杂引发的问题。由于在本申请实施例中，采用低浓度磷原子掺杂钝化层，因此解决了现有技术中掺杂钝化层30对长波段(即800nm～1200nm波长范围)的光产生很强的自由载流子吸收现象，提高了电池效率。进一步地，相比于现有技术中因在 仅降低Poly层磷掺杂浓度下导致场钝化效应变弱以及接触性能变差的情况，在本申请实施例中形成有第一重掺杂区域和第一浅掺杂区域。其中，第一重掺杂区域的掺杂浓度高，第一重掺杂区域的场钝化效应加强，掺杂钝化层与第一电极之间接触良好，保证了填充因子不会下降。第一浅掺杂区域的光寄生吸收减弱，电流收益明显。
另外，相比于现有技术中，为了保证掺杂钝化层与第一电极之间具有良好的欧姆接触，通常情况下，丝网印刷时用于形成第一电极4的银浆印刷线宽较宽，导致单耗较高，成本高。但是，本申请实施例中，通过使第一电极4与第一重掺杂区域63连接，保证了第一电极4与掺杂钝化层30之间具有良好的欧姆接触。因此，可以适当的收窄用于形成第一电极4的银浆印刷线宽，以降低制作成本。
此外，在本申请实施例中形成有第一重掺杂区域和第一浅掺杂区域。其中，第一重掺杂区域的掺杂浓度高，保证了掺杂钝化层与第一电极之间的良好接触，因此，可以适当收窄丝网印刷线宽。第一浅掺杂区域的掺杂浓度低，光寄生吸收相对较弱，减少了电流损失，有利于提高电池效率和降低金属浆料单耗。
在一种可选方式中，掺杂钝化层的厚度大于或等于50nm，且小于或等于200nm。例如，掺杂钝化层的厚度可以是50nm、80nm、100nm、120nm、150nm、180nm或200nm等。相比于现有技术，本申请提供的太阳能电池可以在不减薄掺杂钝化层的厚度的情况下，提高载流子传输效率，减小或消除开压的损失，并确保优异的电极与钝化层的电接触性能。
作为一种可能的实现方式，参见图3，第一重掺杂区域63的宽度大于第一电极4的宽度。在本申请实施例中，第一重掺杂区域63的宽度略大于第一电极4的宽度。此时，便于后期丝网对准和印刷，以确保太阳能电池的质量。
当钝化层为掺杂钝化层30时，半导体基底1可以是N型晶体硅主体。在半导体基底1的受光面S1上依次形成有第二氧化铝钝化层80和第二SiNx减反射钝化层81，半导体基底1的受光面S1具有选择性发射极，选择性发射极包括第 二浅掺杂区域60，以及与第二电极9接触的第二重掺杂区域61。第二电极9穿过第二SiNx减反射钝化层81和第二氧化铝钝化层80与第二重掺杂区域61连接。在掺杂钝化层30上依次形成有第一氧化铝钝化层82和第一SiNx减反射钝化层83，第一电极4穿过第一SiNx减反射钝化层83和第一氧化铝钝化层82与第一重掺杂区域63连接。
需要说明的是，钝化/减反射叠层结构具有如下功能：可以减少太阳能电池表面对光的反射，使更多的光线能够进入太阳能电池内部并被吸收，从而提高光电转换效率；防止外部环境对太阳能电池表面的侵蚀，延长太阳能电池的使用寿命；可以减少太阳能电池内部的光生载流子在传输过程中的复合损失，提高载流子的收集效率，从而提升电池的光电转换效率；还能对太阳能电池的表面进行保护，防止表面缺陷对太阳能电池性能的影响。
第二方面，本申请实施例还提供了一种太阳能电池组件。该太阳能电池的制作方法包括两个或更多个前文所述的太阳能电池，其中，两个或更多个太阳能电池之间以串联的方式电联接，并且太阳能电池组件还包括导电线，该导电线用于将两个或更多个太阳能电池以串联的方式电联接，导电线在钝化层所在的平面内的投影与第一电极在钝化层所在的平面内的投影部分重叠。
采用上述技术方案的情况下，导电线可以直接与第一电极电联接，使得导电线与第一电极之间的联接点相对较小，减少了焊接应力；同时，由于第一电极与钝化层的电接触性能好，即使导电线与第一电极之间的焊接接触面较小，同样能够保证导电线与太阳能电池之间的充分电性连接，保证了TOPCon电池的电池效率。
可选地，第一电极上可以设置有焊点结构，导电线通过焊接与该焊点结构电连接，其中，在垂直于第一电极的延伸方向的方向上，焊点结构的宽度大于第一电极的宽度。
第三方面，本申请实施例还提供了一种太阳能电池的制作方法。该太阳能电池的制作方法包括：
参见图1至图3，首先，提供一半导体基底1，半导体基底1具有相对的受光面S1和背光面S2。关于半导体基底的描述请参考第一方面，在此不做具体限定。
接下来，对半导体基底1进行制绒处理。
示例性的，使用碱和添加剂对N型原硅片进行双面制绒。
接下来，对制绒后的半导体基底1进行硼扩散处理。
示例性的，在半导体基底1的受光面S1形成硼扩散层和BSG(硼硅玻璃，Borosilicate glass)层。
接下来，对硼扩散层和BSG层进行局部激光掺杂处理。
接下来，对激光掺杂处理后的结构进行高温氧化处理。
经过上述处理后，半导体基底1的受光面S1一侧形成第二重掺杂区域61(对应激光掺杂处理的区域)，剩余硼扩散层为第二浅掺杂区域60。
接下来，去除半导体基底1的背光面S2和侧面绕扩的硼扩散层和BSG层，再通过NaOH或KOH碱溶液对半导体基底1的背光面S2进行抛光处理。
接下来，在半导体基底1的背光面S2和受光面S1中的至少一面上形成超薄介质层2。
在一种实现方式中，超薄介质层2的厚度大于或等于1nm，且小于或等于2nm。超薄介质层2的厚度方向与受光面S1至背光面S2的方向一致。例如，超薄介质层2的厚度为1nm、1.4nm、1.6nm、1.9nm或2nm等。和/或，超薄介质层2的材质包括氧化硅、氧化铪、氧化铝、氮化硅中的一种。
接下来，在超薄介质层2上形成钝化层3。
作为一种可能的实现方式，在超薄介质层2上形成钝化层3后，太阳能电池的制作方法还包括：
对钝化层3进行掺杂扩散处理，以形成掺杂钝化层30；
示例性的，使用低压扩散炉对钝化层3进行磷掺杂，掺杂扩散处理中扩散温度大于或等于800℃，且小于或等于830℃。例如，800℃、805℃、810℃、 815℃或830℃等。推结温度大于或等于850℃，且小于或等于900℃。例如，850℃、860℃、880℃、890℃或900℃等。
接下来，对掺杂钝化层30进行后扩散沉积处理，以在掺杂钝化层30上形成第二掺杂源层；
在一种实现方式中，在掺杂钝化层30上形成一层PSG(磷硅玻璃，Phosphorosilicateglass)层。后扩散沉积处理中扩散温度大于或等于820℃，且小于或等于850℃。例如，820℃、825℃、830℃、840℃或850℃等。
接下来，采用激光照射工艺对第二掺杂源层进行区域性处理，以在掺杂钝化层30内形成第一重掺杂区域63；剩余掺杂钝化层30为第一浅掺杂区域62；
示例性的，利用激光将富磷的PSG层中的磷原子推进到掺杂钝化层30内，在掺杂钝化层30内形成第一重掺杂区域。
其中，第一重掺杂区域63与第一电极4对应连接；第一重掺杂区域63的掺杂浓度大于第一浅掺杂区域62的掺杂浓度。
采用上述技术方案的情况下，由于第一重掺杂区域63与第一电极4对应连接，因此可以保证第一电极4与掺杂钝化层30之间具有良好的欧姆接触，以提高填充因子。进一步地，由于第一浅掺杂区域62不与第一电极4接触，形成了非金属接触区，并且第一浅掺杂区域62的掺杂浓度较低。因此，有利于降低非金属接触区的俄歇复合以及降低掺杂钝化层对紫外光的寄生吸收。
接下来，去除半导体基底1的受光面S1和侧面绕扩的磷扩散层以及PSG层，再去除受光面S1绕镀的掺杂钝化层30和受光面S1的BSG层和背光面S2的PSG层；
接下来，在掺杂钝化层30上形成第一氧化铝钝化层82；在半导体基底1的受光面S1上形成第二氧化铝钝化层80；
接下来，在第一氧化铝钝化层82上形成第一SiNx减反射钝化层83；在第二氧化铝钝化层80上形成第二SiNx减反射钝化层81；
接下来，形成第一电极4和第二电极9。
位于背光面S2的第一电极4穿过第一SiNx减反射钝化层83和第一氧化铝钝化层82与第一重掺杂区域63连接。位于受光面S1的第二电极9穿过第二SiNx减反射钝化层81和第二氧化铝钝化层80与第二重掺杂区域61连接。
钝化层3内形成有金属晶体，其中，金属晶体包括第一金属晶体50，第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面与第一电极4连接。
与现有技术相比，在本申请实施例提供的太阳能电池的制作方法中，可以在不减薄钝化层3的情况下，提高载流子传输效率，减小或消除开压的损失，并确保电极与钝化层之间优异的电接触性能。进一步地，由于第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面与第一电极4连接，形成了金属-超薄介质-半导体的结构。又由于第一金属晶体50位于钝化层3内，第一金属晶体50与钝化层3充分接触。基于此，通过控制第一金属晶体50的比率可以优化填充因子，平衡开压和填充因子。再进一步地，在第一金属晶体50的作用下，有利于载流子移动到第一电极4，加快了载流子的传输速率，进而缩短了载流子穿过钝化层3所需的时间。此外，由于第一金属晶体50并未穿过超薄介质层2进入半导体基底1，此时，不仅可以确保超薄介质层2不被破坏，以确保超薄介质层2的功能不受影响。即，保证了超薄介质层良好的化学钝化和隧穿效应。同时，还可以减小对开压的影响，以避免半导体基底1被破坏，以确保半导体基底1的功能不受影响，进而确保太阳能电池的性能。
综上所述，第一金属晶体与超薄介质层抵接，未破坏超薄介质层结构，因此保证了超薄介质层良好的化学钝化和隧穿效应。超薄介质层作为多数载流子的隧穿传输层，可以传输半导体基底中的多数载流子通过超薄介质层。紧接着，第一金属晶体承担着快速传输通过超薄介质层的多数载流子到第一电极的作用，以确保获得更高的填充因子，背光面钝化结构良好的多数载流子传输效率可以获得较小的接触电阻率和串联电阻，从而确保获得更高的电池效率。
作为一种可能的实现方式，第一金属晶体的数量与金属晶体的总数量的比 值大于或等于2％，且小于或等于20％。例如，比值可以是2％、5％、8％、12％、15％、17％、18％或20％等。此时，可以避免因第一金属晶体的数量过多影响隧穿-多晶的载流子隧穿效果。
作为一种可能的实现方式，参见图2，沿第一电极4向钝化层3的方向，第一金属晶体50的宽度逐渐减小。
采用上述技术方案的情况下，沿第一电极向钝化层的方向，第一金属晶体的宽度逐渐减小，减小了对钝化层和半导体基底的腐蚀，减小了金属-超薄介质层界面的金属复合。进一步地，沿钝化层向第一电极的方向，第一金属晶体的宽度逐渐增加，增大了第一金属晶体与第一电极的接触面积，有利于提升第一金属晶体输运沿受光面到背光面的多数载流子到第一电极的传输效率。
示例性的，沿第一电极4向钝化层3的方向，第一金属晶体50呈大致梯形的形态。
在一种可选的方式中，第一金属晶体50的一端面与超薄介质层2抵接，第一金属晶体50的另一端面深入第一电极4内，具体深入的尺寸可以根据实际情况进行设置。
作为一种可能的实现方式，参见图2，金属晶体5还包括：第二金属晶体51。第二金属晶体51与第一电极4连接，且与第一金属晶体50间隔分布。第二金属晶体51的厚度小于钝化层3的厚度，第二金属晶体51的厚度方向和钝化层3的厚度方向均与背光面S2至受光面S1的方向一致。应理解，第二金属晶体51的一端面也可以深入第一电极4内，其中，第二金属晶体51深入第一电极4内的尺寸以及第二金属晶体51的厚度根据实际情况进行设置，在此不做具体限定。
此时，不仅更有利于载流子移动到第一电极4，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层3所需的时间，以确保TOPCon电池的电池效率。同时，还可以降低第一电极4和钝化层3之间的接触电阻。进一步地，由于第二金属晶体51的厚度小于钝化层3的厚度，因此可以避免第二金属 晶体51损伤超薄介质层2和半导体基底1，以确保太阳能电池的性能。
在一种可选方式中，多个第二金属晶体间隔分布。和/或，第二金属晶体的数量与金属晶体的总数量的比值大于或等于50％，且小于或等于90％。例如，比值可以是50％、58％、62％、75％、82％或90％等。
采用上述技术方案的情况下，不仅更有利于载流子移动到第一电极，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层所需的时间，以确保TOPCon电池的电池效率。同时，还可以降低第一电极和钝化层之间的接触电阻。进一步地，由于第二金属晶体的厚度小于钝化层的厚度，因此可以避免第二金属晶体损伤超薄介质层和半导体基底，以确保太阳能电池的性能。
在一种可选方式中，参见图2，金属晶体5还包括：第三金属晶体52。第三金属晶体52与第一电极4、超薄介质层2和第二金属晶体51均间隔分布。即第三金属晶体52即不与第一电极4连接，也不与超薄介质层2连接。
此时，更有利于载流子移动到第一电极4，进一步加快载流子的传输速率，进而进一步缩短载流子穿过钝化层3所需的时间，以确保TOPCon电池的电池效率。进一步地，由于第三金属晶体52与超薄介质层2间隔分布，因此可以避免第三金属晶体52损伤超薄介质层2和半导体基底1，以确保太阳能电池的性能。
在一种可选方式中，参见图2，多个第三金属晶体52离散分布在钝化层3内。和/或，沿第一电极4向钝化层3的方向，第三金属晶体52与第一电极4之间的间距小于第三金属晶体52与超薄介质层2之间的间距。在本申请实施例中，第三金属晶体52与第一电极4之间的间距小于钝化层3厚度的一半。和/或，第二金属晶体51的数量与金属晶体的总数量的比值小于或等于5％。
在一种可选方式中，参见图2，由于较小尺寸的金属晶体易于脱离第一电极4主体，但是较难向更深入钝化层3的方向生长和延伸。因此，第三金属晶体52的平均体积和第二金属晶体51的平均体积的比值小于或等于10％。
采用上述技术方案的情况下，较小尺寸的第三金属晶体52易于脱离第一电 极4主体，在实际制作过程中，上述第三金属晶体是不希望出现的，但是在制作时又不可避免的会出现。因此，需要控制第三金属晶体的平均体积和数量在上述取值范围内，以降低第三金属晶体对太阳能电池效率产生的影响。
结合前文描述，相比于第二金属晶体51和第三金属晶体52，第一金属晶体50的尺寸最大。进一步地，第一金属晶体50、第二金属晶体51和第三金属晶体52均间隔分布。
在上述实施方式的描述中，具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (17)

  1. 一种太阳能电池，其中，包括：
    半导体基底，具有相对的受光面和背光面；
    超薄介质层，位于所述半导体基底的所述背光面和所述受光面中的至少一面上；
    钝化层，位于所述超薄介质层上；
    第一电极，位于所述钝化层上；
    金属晶体，位于所述钝化层内；
    其中，所述金属晶体包括第一金属晶体，所述第一金属晶体的一端面与所述超薄介质层抵接，所述第一金属晶体的另一端面与所述第一电极连接。
  2. 根据权利要求1所述的太阳能电池，其中，在所述背光面和所述受光面中的至少一面上局部地设置有所述钝化层。
  3. 根据权利要求1所述的太阳能电池，其中，所述第一金属晶体的数量与所述金属晶体的总数量的比值大于或等于2％，且小于或等于20％。
  4. 根据权利要求1所述的太阳能电池，其中，沿所述第一电极向所述钝化层的方向，所述第一金属晶体的宽度逐渐减小。
  5. 根据权利要求1所述的太阳能电池，其中，所述金属晶体还包括：
    第二金属晶体，与所述第一电极连接，且与所述第一金属晶体间隔分布；所述第二金属晶体的厚度小于所述钝化层的厚度，所述第二金属晶体的厚度方向和所述钝化层的厚度方向均与所述背光面至受光面的方向一致。
  6. 根据权利要求5所述的太阳能电池，其中，多个所述第二金属晶体间隔分布；和/或，
    所述第二金属晶体的数量与所述金属晶体的总数量的比值大于或等于50％，且小于或等于90％。
  7. 根据权利要求5所述的太阳能电池，其中，所述金属晶体还包括：
    第三金属晶体，与所述第一电极、所述超薄介质层和所述第二金属晶体均间隔分布。
  8. 根据权利要求7所述的太阳能电池，其中，多个所述第三金属晶体离散分布在所述钝化层内；和/或，
    沿所述第一电极至所述钝化层的方向，所述第三金属晶体与所述第一电极之间的间距小于所述第三金属晶体与所述超薄介质层之间的间距；和/或，
    所述第二金属晶体的数量与所述金属晶体的总数量的比值小于或等于5％；和/或，
    所述第三金属晶体的平均体积和所述第二金属晶体的平均体积的比值小于或等于10％。
  9. 根据权利要求1至8中任一项所述的太阳能电池，其中，所述钝化层为掺杂钝化层时，所述掺杂钝化层包括：
    第一重掺杂区域，与所述第一电极对应连接；
    第一浅掺杂区域，位于所述第一重掺杂区域一侧；所述第一重掺杂区域的掺杂浓度大于所述第一浅掺杂区域的掺杂浓度。
  10. 根据权利要求9所述的太阳能电池，其中，所述掺杂钝化层的厚度大于或等于50nm，且小于或等于200nm。
  11. 根据权利要求1所述的太阳能电池，其中，所述超薄介质层的厚度大于或等于1nm，且小于或等于2nm；所述超薄介质层的厚度方向与受光面至背光面的方向一致；和/或，
    所述超薄介质层的材质包括氧化硅、氧化铪、氧化铝、氮化硅中的一种。
  12. 一种太阳能电池组件，包括两个或更多个根据权利要求1-11中任一项所述的太阳能电池，其中，两个或更多个所述太阳能电池之间以串联的方式电联接，并且所述太阳能电池组件还包括导电线，所述导电线用于将两个或更多个所述太阳能电池以串联的方式电联接，所述导电线在所述钝化层所在的平面内的投影与所述第一电极在所述钝化层所在的平面内的投影部分重叠。
  13. 一种太阳能电池的制作方法，其中，包括：
    提供一半导体基底；所述半导体基底具有相对的受光面和背光面；
    在所述半导体基底的所述背光面和所述受光面中的至少一面上形成超薄介质层；
    在所述超薄介质层上形成钝化层；
    在所述钝化层上形成第一电极；所述钝化层内形成有金属晶体；
    其中，所述金属晶体包括第一金属晶体，所述第一金属晶体的一端面与所述超薄介质层抵接，所述第一金属晶体的另一端面与所述第一电极连接。
  14. 根据权利要求13所述的太阳能电池的制作方法，其中，所述第一金属晶体的数量与所述金属晶体的总数量的比值大于或等于2％，且小于或等于20％。
  15. 根据权利要求14所述的太阳能电池的制作方法，其中，沿所述第一电极向所述钝化层的方向，所述第一金属晶体的宽度逐渐减小。
  16. 根据权利要求13所述的太阳能电池的制作方法，其中，在所述超薄介质层上形成钝化层后，所述太阳能电池的制作方法还包括：
    对所述钝化层进行掺杂扩散处理，以形成掺杂钝化层；
    对所述掺杂钝化层进行后扩散沉积处理，以在掺杂钝化层上形成第二掺杂源层；
    采用激光照射工艺对所述第二掺杂源层进行区域性处理，以在所述掺杂钝化层内形成第一重掺杂区域；剩余所述掺杂钝化层为第一浅掺杂区域；
    其中，第一重掺杂区域与所述第一电极对应连接；所述第一重掺杂区域的掺杂浓度大于所述第一浅掺杂区域的掺杂浓度。
  17. 根据权利要求16所述的太阳能电池的制作方法，其中，
    所述掺杂扩散处理中扩散温度大于或等于800℃，且小于或等于830℃；
    所述后扩散沉积处理中扩散温度大于或等于820℃，且小于或等于850℃。
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