Classifications

• • 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
  • H10F19/904—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers for series or parallel connection of photovoltaic cells characterised by the shapes of the structures
• • 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
  • H10F19/80—Encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells
  • H10F19/807—Double-glass encapsulation, e.g. photovoltaic cells arranged between front and rear glass sheets
• • 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
  • H10F19/906—Structures for connecting between photovoltaic cells, e.g. interconnections or insulating spacers for series or parallel connection of photovoltaic cells characterised by the materials of the structures
• • 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
  • H10F71/137—Batch treatment of the devices
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy

Definitions

• the present invention relates to the field of photovoltaic modules, in particular intended for a space application.
• the present invention relates more particularly to the problem of interconnectors and assemblies between chains (or "strings" according to the English terminology) of solar cells to form a photovoltaic module. It finds a particularly advantageous application in the field of interconnections and assemblies between strings of solar cells, and in particular between strings of solar cells forming a photovoltaic module intended for a space application.
• interconnection makes it possible to establish an electrical connection between two individual solar cells or between several strings of a photovoltaic module via a conductive material called an interconnector.
• the designs and techniques of interconnection between two individual solar cells are generally different between terrestrial applications and space applications.
• the standard interconnection between two individual solar cells consists of the use of copper and tinned interconnecting ribbons, soldered or glued, on the solar cells.
• the standard thickness of each of these interconnect tapes is of the order of 200 ⁇ m for a width varying from a few hundred microns to a few millimeters.
• the corresponding section is compatible with the operating currents of silicon-based solar cells, generally implemented for terrestrial applications. These currents are standard between 6 and 12 A.
• the interconnection standard between two individual solar cells consists of the use of molybdenum, Invar (FeNi) or Kovar (FeNiCo), silver or gold plated interconnectors, which are resistance welded (or equivalently by "welding" according to the Anglo-Saxon terminology).
• These interconnectors have a specific geometry making it possible to withstand the high thermal amplitudes of the space environment.
• the standard thickness of these interconnectors is around 25 ⁇ m for a width of up to several millimeters. This section is compatible with the operating currents of spatial multi-junction cubicles which are standardly less than 1 A.
• the Hubble telescope implements silicon cells whose surface area of 2 cm x 4 cm allows the use of a silver-plated molybdenum interconnector, including a so-called “out-of-plane” relaxation loop, to electrically link two cells together. individual sunscreens. It is therefore possible to use, for space applications, silicon-based solar cells interconnected two by two by interconnectors developed for space applications.
• interconnecting ribbon cell such as those making it possible to interconnect two adjacent cells of a chain (by extending for example over a first of the two cells to under the other of the two adjacent cells between them for a series connection of these cells), one end of said at least one interconnecting ribbon extending at the end of the chain; such a ribbon will hereinafter be called "interconnection ribbon cell", and
• string interconnection strip at least one interconnection strip between strings and/or between several ends of cell interconnection strips at the end of the string, and which we will hereinafter call “string interconnection strip”.
• this assembly presents risks of breakage of the panels, in particular during their manufacture.
• extra thicknesses at the level of the assemblies between cell interconnection ribbon and chain interconnection ribbon can lead to the breakage of the glass plates, in particular during their transfer.
• extra thicknesses are all the more observable when cell interconnection tape(s) and string interconnection tape(s) are interconnected by soldering or gluing, both of which involve an addition of material.
• An object of the present invention is to propose an assembly between cell interconnection tape(s) and chain interconnection tape(s) which makes it possible to overcome at least one of the drawbacks of the state of the art.
• An object of the present invention is more particularly to propose an assembly between cell interconnection tape(s) and string interconnection tape(s) which makes it possible to limit, or even eliminate, the risk of panel breakage, in particular during of their production.
• Another object of the invention is to provide a solution for integrating silicon-based solar cell panels suitable for both space and terrestrial applications.
• an interconnector for at least one string of solar cells intended to form at least part of a photovoltaic module.
• the interconnector comprises at least one cell interconnection ribbon extending in part over a cell of the chain, the cell being located at the end of the chain. Each cell interconnect strip extends beyond said cell over which it extends at one end.
• the interconnect further includes at least one string interconnect ribbon.
• Each string interconnect strip can be arranged to interconnect at least two ends of cell interconnect strips and/or at least two cell strings.
• Each of said at least one cell interconnect ribbon and said at least one string interconnect ribbon extends along a main direction over a thickness measured along a direction perpendicular to a plane in which the string of solar cells mainly extends .
• a section in a plane perpendicular to said main direction of an element taken from said at least one cell interconnection ribbon and said at least one chain interconnection ribbon has:
• - a variable shape along the main direction at least between a first zone of thickness Z1 and a second zone of thickness Z2, the thickness Z2 of the second zone being strictly less than the thickness Z1 of the first zone and the thickness Z2 of the second zone being strictly less than 50 ⁇ m.
• each second zone can constitute an electrically conductive welding zone, and in particular a resistance welding zone (or “welding” according to the English terminology).
• the weld zones may have been punched to locally reduce the thickness of the interconnection means, while maintaining the section of these means so as not to lose electrical performance.
• the interconnector according to the first aspect of the invention makes it possible to produce photovoltaic modules, in particular with silicon-based solar cells, which resist the thermal stresses of the space environment.
• the absence of solder or glue due to the possibility of using the resistance soldering technique makes it possible to limit the number of different materials involved in the interconnection and therefore is less subject to differences in coefficients of thermal expansion. between materials involved.
• a second aspect relates to a photovoltaic module comprising solar cells, preferably based on silicon, and at least one interconnector as introduced above.
• a third aspect concerns a method for assembling a photovoltaic module according to the second aspect of the invention.
• the assembly method includes a step of resistance welding between said at least one cell interconnect ribbon and said at least one chain interconnect ribbon at at least one second zone.
• Figure 1 schematically represents a top view of a photovoltaic panel according to a first known architecture.
• FIG. 2A schematically represents a top view of a photovoltaic panel according to a second known architecture.
• Figure 2B shows an enlargement of the area referenced A in Figure 2A.
• FIG. 3A schematically represents a top view of a first embodiment of the invention.
• FIG. 3B schematically represents a partial sectional view of the first embodiment of the invention according to the section plane referenced A-A in FIG. 3A.
• Figure 4 schematically shows a partial sectional view of a second embodiment of the invention.
• Figure 5 schematically represents a partial sectional view of a third embodiment of the invention.
• FIG. 6A schematically represents a partial sectional view of a photovoltaic module 1 according to the prior art.
• FIG. 6B schematically represents a partial sectional view of a photovoltaic module 1 according to one embodiment of the invention.
• FIGS. 7A and 7B each illustrate a step of the method for stamping the end of a cell interconnection ribbon of an interconnector according to one embodiment of the invention.
• said element being a cell interconnection ribbon, it comprises a second zone located at the level of the end by which it extends beyond the cell located at the end of the chain.
• said element being a chain interconnection ribbon, it comprises a second zone per cell interconnection ribbon devoid of a second zone, or even per cell interconnection ribbon, each second zone of the chain interconnection ribbon being preferably distant from at least one other second zone of the string interconnection ribbon by a distance substantially equal to a separation distance between cell interconnection ribbons adjacent to each other, the latter being arranged substantially parallel to each other.
• the interconnector comprises at least two cell interconnection ribbons, and at least one, preferably each, of the ends of said at least two cell interconnection ribbons is interconnected to the other of the two ends by said at least a chain interconnect ribbon by being resistance welded thereto at at least a second area.
• the interconnector comprises at least two cell interconnection ribbons, and at least one, preferably each, of the ends of said at least two cell interconnection ribbons is interconnected at the other of the two ends by a ribbon of chain interconnection by being welded thereto by resistance at the level of two second zones superposed between them, one belonging to one of said at least two cell interconnect ribbons, the other to the chain interconnect ribbon.
• the first zone has a thickness greater than or equal to 70 ⁇ m, preferably greater than 100 ⁇ m, and even more preferably substantially equal to 200 ⁇ m, the thickness being measured perpendicular to a plane in which the string of solar cells.
• the thickness Z1 is the maximum thickness that the element has over its entire extent along the main direction.
• the part of each interconnecting ribbon which extends over the cell located at the end of the chain is free of a second zone. This avoids opacifying the cell and proportionally reducing its efficiency.
• the width of each interconnecting strip at the level of each first zone is less than or substantially equal to 1 mm.
• each second zone extends over:
• said element comprises a relaxation loop.
• said element is based on copper, and comprises, where appropriate, surface tinning with a thickness substantially between 20 and 25 ⁇ m and/or a composition of pure Ag, SnAg, SnPbAg or SnBiAg.
• the interconnector is more particularly an interconnector for at least one chain of silicon-based solar cells.
• the interconnect is free of solder or glue.
• said at least one interconnector provides an electrical junction between at least two strings of solar cells, according to a series or parallel configuration of said at least two strings, and/or
• At least one interconnector is intended to make an electrical junction between at least one chain of solar cells and external electronics.
• the photovoltaic module according to the second aspect of the invention comprises two protective plates and an encapsulant, said at least one interconnector and said at least one string of solar cells being encapsulated by the encapsulant sandwiched between the two protective plates, the latter being, where appropriate, made from glass.
• the assembly method according to the third aspect of the invention further comprises a stamping step, in a mold comprising an imprint and a punch, of a cell interconnection strip of constant section and thickness equal to said thickness Z1.
• the cavity and the punch are preferably configured to deform the end of the cell interconnection ribbon by forcing it to gradually spread out transversely to its thickness so as to keep the length of the cell interconnection ribbon unchanged while progressively reducing its thickness until it reaches said thickness Z2 and forms a second zone.
• chain (or “string”) of solar cells means a substantially linear succession of solar cells in a plane, the cells being interconnected by at least one interconnecting ribbon between each pair of successive cells in the 'alignment.
• each interconnecting ribbon joins together the two cells of each pair by extending under a first of the two cells, then over the second of the two cells, a space between the cells being provided at the level of which the interconnecting ribbon changes sides relative to the plane in which the cells fit.
• the term “thickness” designates, unless otherwise stated, a dimension of the object concerned which is perpendicular to a plane in which a chain of solar cells mainly extends, or a photovoltaic module comprising this chain.
• width designates the dimension of a longitudinal object, such as a ribbon, which is perpendicular to the longitudinal extension direction of the object and parallel to the plane in which the photovoltaic module mainly extends.
• the "section" of a longitudinal object is defined by the shape, area and dimensions of a transverse plane section of this object.
• a parameter “substantially equal/greater/less than” a given value is meant that this parameter is equal/greater/less than the given value, to plus or minus 10%, or even 5%, close to this value.
• a parameter “substantially between” two given values means that this parameter is at least equal to the smallest given value, to plus or minus 10%, or even 5%, close to this value, and at most equal to the smallest value. large given value, more or less 10%, or even 5%, close to this value.
• substantially refers to the quality of an object, for example when it is a question of an object of substantially constant section, it is because this quality accommodates at least certain measurement errors or this quality is to be assessed with regard to the function of the object, and/or a possible acceptable degradation of this function, having regard to the whole, such as a photovoltaic module, in which the object is part.
• each of the interconnecting strips in question here is preferably constant, within measurement errors, but may also vary slightly, beyond said measurement errors, if its function which is to conduct, for example according to certain specifications of a specification, the electric current produced by the solar cells is not altered to the point that the photovoltaic module comprising the interconnecting ribbons would no longer be functional or would lose all interest due to a yield too weak.
• the invention aimed to allow a wider use of photovoltaic panels composed of photovoltaic modules whose solar cells are based on silicon for space applications.
• the impossibility of welding interconnection ribbons together with the resistance welding process was observed when the thickness of the elements to be welded together was of the order of 200 microns, as c This is the case of elements widely used to interconnect strings of silicon-based solar cells for terrestrial applications. Indeed, resistance welding of such thicknesses of materials requires a significant energy input, which is not compatible with current equipment and/or leads to deformations and significant aesthetic defects.
• interconnect tapes used for terrestrial applications being often copper-based have a coefficient of thermal expansion (about 17 ppm for copper) higher than those of materials such as molybdenum (whose coefficient of thermal expansion is approximately 4.8 ppm), invar® (whose coefficient of thermal expansion is approximately 1.6 ppm) and Kovar® (whose coefficient of thermal expansion is approximately 5.1 ppm) used for their part to constitute interconnectors specific to space applications.
• materials such as molybdenum (whose coefficient of thermal expansion is approximately 4.8 ppm), invar® (whose coefficient of thermal expansion is approximately 1.6 ppm) and Kovar® (whose coefficient of thermal expansion is approximately 5.1 ppm) used for their part to constitute interconnectors specific to space applications.
• Copper-based interconnect tapes are therefore a priori less good candidates for constituting interconnectors specific to space applications.
• interconnectors for terrestrial applications often copper-based as mentioned above, are usually assembled by brazing the interconnecting ribbons together.
• Such solders give them low resistance to the space environment, in particular because of the temperatures prevailing there, and the temperature differences observed there. Indeed, these temperatures are at the origin of strong mechanical stresses highly likely to cause the rupture of weld joints obtained by brazing, as by gluing.
• an interconnector 10 has been proposed for at least one chain 20 of solar cells 200 intended to form a photovoltaic module 1 according to the present invention.
• the interconnector 10 can make it possible to electrically interconnect two strings 20 of solar cells 200 with one another and/or to electrically interconnect a string 20 of solar cells 200 to external electronics.
• FIG. 1 illustrates a series connection of four strings 20 of solar cells 200.
• an interconnector represented respectively at the top, on the left and on the right, of FIG. 1 intended to allow direct or indirect connection to external electronics.
• an interconnector electrically connecting the two chains 20 located in the center of the photovoltaic module 1.
• two other interconnectors connecting respectively the two chains 20 on the right and the two chains 20 left.
• FIG. 1 is an example of an architecture known from the prior art to which the invention applies advantageously.
• FIG. 2A illustrates another example of this type of known architecture on which the invention is intended to apply.
• each solar cell illustrated in FIG. 2A has a square shape, the side of which can be approximately equal to 15 cm.
• the number of electrical connections to be made with each chain interconnection tape 12 being proportional to the number of cell interconnection tapes 11 extending over each solar cell 200 at the end of the chain 20 and each interconnection potentially being a break zone, it it appears that the present invention will be even more advantageously applied to this second type of architecture illustrated, relative to the first type of architecture.
• Figure 2B is an enlargement of the area referenced A illustrated in Figure 2A.
• the present invention relates in the first place to the interconnections between ends 111 of the cell interconnection ribbons 11 at the end of the chain 20 of solar cells 200 and a chain interconnection ribbon 12, but also extends to any interconnections between ribbons of chain interconnection 12, in particular as illustrated in FIG. 2B.
• an interconnector 10 comprising:
• each chain interconnection ribbon 12 interconnecting with the end 111 of each cell interconnection ribbon 11, five in number in FIG. 2A.
• Each interconnecting ribbon 11 and said at least one chain interconnecting ribbon 12 extends along a main direction over a thickness measured along a direction perpendicular to a plane (x,y) in which the chain 20 mainly extends from 200 solar cells.
• Interconnector 10 is essentially such that a section in a plane perpendicular to said main direction, x or y, of an element 11, 12 taken from said at least cell interconnection ribbon 11 and said at least one string 12 interconnect features:
• FIGS. 3A and 3B illustrate an embodiment in which each cell interconnection strip 11 comprises a second zone 102 located at the level of the end 111 by which it extends beyond the cell 200 located at the end of the chain 20.
• each cell interconnect strip 11 may have been molded in the manner illustrated by the top views shown in Figures 7A and 7B. More specifically, the end 111 of each cell interconnection ribbon 11 may have been wedged against a wall of a cavity of a mold 4, before a punch from the mold 4 comes to crush the end 111 of the ribbon of cell interconnection 11 illustrated in FIG. 7A to deform it by forcing it to gradually spread transversely to its thickness so as to keep the length of the cell interconnection strip 11 unchanged while gradually reducing its thickness until said thickness is reached Z2 and form a second area 102 as shown in Figure 7B. In this way, the section of the cell interconnection ribbon 11 is kept constant over its entire length. As a result, its electrical performance is maintained.
• the width in the x direction of the cell interconnection ribbon 11 increases in the y direction at the level of its end 111, while its height in the z direction decreases.
• the end 111 thus deformed preferably ends with a substantially planar surface inscribed in the plane (x,y) in which the chain 20 of solar cells 200 mainly extends. Alternatively or in addition, this surface is substantially equal to 1 mm 2 in projection on the plane (x,y).
• the end 111 of said at least one cell interconnection strip 11 according to the first embodiment of the invention has a surface by which it is possible, and particularly easy, to solder it by resistance to said at least one chain interconnection tape 12.
• the interconnection thus obtained is advantageously free of solder or glue, in particular with a view to space applications.
• FIG. 4 A second embodiment, having the same advantages, is illustrated in Figure 4.
• it is said at least one chain interconnecting ribbon 12 which comprises a second zone 102; it more particularly comprises one per cell interconnection ribbon 11, each cell interconnection ribbon 11 being free of a second zone 102.
• the section of the ribbon d The chain interconnect 12 illustrated in Figure 4 is much more extended in the y direction. This difference is explained by the conservation of the surface of the section in the plane (y, z) of the chain interconnecting ribbon 12.
• the second zones 102 of the chain interconnection ribbon 12 are preferably separated from each other by a distance equal to a separation distance between the interconnection ribbons 11 arranged for their part substantially parallel to each other on the cell 200 located at the end of chain 20.
• Such chain interconnect ribbons 12 can easily be manufactured to these specifications.
• each cell interconnection ribbon 11 with the chain interconnection ribbon 12 will preferably be carried out by the surface of the chain interconnection ribbon 12 d thickness Z2 located opposite said end 111.
• a third embodiment is shown in Figure 5.
• each cell interconnection ribbon 11 comprises a second zone 102 and the chain interconnection ribbon 12 comprises as many second zones 102 as there are cell interconnection ribbons 11 to be interconnected between them.
• the resistance welding of the end 111 of each cell interconnection strip 11 with the chain interconnection strip 12 can be carried out by one or the other among the surface of the chain interconnection strip 12 of thickness Z2 located opposite said end 111 and the surface of the end 111 of each cell interconnection strip 11 of thickness Z2 located opposite the chain interconnect ribbon 12.
• the first zone 101 can have a thickness greater than or equal to 70 ⁇ m. It can even be greater than or equal to 100 pm, as is the case with interconnect ribbons often used nowadays.
• the thickness Z1 is preferably the maximum thickness exhibited by each interconnecting strip 11 and/or 12 over its entire extent along its main direction of extension.
• the part of each cell interconnection strip 11 which extends over the cell 200 located at the end of the chain 20 is preferably free of a second zone 102; in this way, shading of the energy collection surfaces of said solar cell 200 is avoided.
• each cell interconnection strip 11 at the level of each first zone 101 is less than or substantially equal to 1 mm, so as to optimize the energy collection surface of said solar cell 200. For this reason, it is not conceivable to be satisfied with using interconnecting strips having a constant section of thickness Z2 and of surface area equal to that of a strip of thickness equal to 200 microns, because that would amount to overshadow the cells 200 over which such interconnect ribbons would extend. Note that, in this example, keeping the section of the interconnect ribbon by going from a thickness of 200 microns to a thickness of 50 microns induces a quadrupling of the width of the ribbon.
• FIG. 7A The configuration illustrated in Figure 7A relates to the prior art and the configuration illustrated in Figure 7B relates to the present invention. They illustrate the same so-called glass-glass configuration of a photovoltaic module 1.
• FIG. 7A is illustrated, by the drawing of an impact, the possibility that the photovoltaic module according to the prior art breaks due to the superimposed thicknesses of the ribbons interconnection 11 and 12. It should be noted that this illustration does not show the solder material or the glue which further increases the thickness of the interconnection as shown.
• FIG. 7B it can be seen in FIG. 7B that the thickness at the level of the interconnection between each cell interconnection ribbon 11 and the chain interconnection ribbon 12 is advantageously reduced due to the implementation of the invention, as illustrated here by its first embodiment, but as is true for each of its embodiments.
• an advantage of the present invention is to limit, or even eliminate, the risk of breakage of the photovoltaic module 1, in particular during its manufacture, but also during its use due to thermal stresses. .
• the present invention therefore ultimately makes it possible to respond to a broader problem than that initially considered.
• the interconnector 10 can also comprise a relaxation loop. This loop makes it possible to absorb the differences in thermal expansion coefficient of the various materials and the significant temperature differences.

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• 2020
  • 2020-12-16 FR FR2013393A patent/FR3117673B1/fr active Active
• 2021
  • 2021-12-16 US US18/257,439 patent/US20240105872A1/en not_active Abandoned
  • 2021-12-16 EP EP21839947.5A patent/EP4264675A1/de active Pending
  • 2021-12-16 WO PCT/EP2021/086088 patent/WO2022129278A1/fr not_active Ceased

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