WO2022253174A1 - 集流体及制备的方法、负极和电化学储能装置 - Google Patents

集流体及制备的方法、负极和电化学储能装置 Download PDF

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Publication number
WO2022253174A1
WO2022253174A1 PCT/CN2022/095943 CN2022095943W WO2022253174A1 WO 2022253174 A1 WO2022253174 A1 WO 2022253174A1 CN 2022095943 W CN2022095943 W CN 2022095943W WO 2022253174 A1 WO2022253174 A1 WO 2022253174A1
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Prior art keywords
current collector
polymer layer
layer
lithium
metal layer
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PCT/CN2022/095943
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English (en)
French (fr)
Inventor
潘仪
谢静
郭姿珠
孙华军
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BYD Co Ltd
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BYD Co Ltd
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Priority to CA3220863A priority Critical patent/CA3220863A1/en
Priority to EP22815219.5A priority patent/EP4333128A4/en
Priority to KR1020237045147A priority patent/KR102958075B1/ko
Priority to JP2023574141A priority patent/JP7769727B2/ja
Publication of WO2022253174A1 publication Critical patent/WO2022253174A1/zh
Priority to US18/521,727 priority patent/US20240105962A1/en
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/658—Means for temperature control structurally associated with the cells by thermal insulation or shielding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/40—Alloys based on alkali metals
    • H01M4/405—Alloys based on lithium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • H01M4/662—Alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/666—Composites in the form of mixed materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • H01M4/742—Meshes or woven material; Expanded metal perforated material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/80—Porous plates, e.g. sintered carriers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of energy storage, in particular to a current collector and a preparation method, a negative electrode and an electrochemical energy storage device.
  • Lithium batteries have the characteristics of high energy density, good cycle stability, and safety, and are widely used in many fields such as mobile phones, computers, automobiles, and grid energy storage.
  • the lithium foil used in lithium metal batteries will bring higher cost and safety hazards in the battery manufacturing process, so it is motivated to use only current collectors as negative electrode materials, that is, lithium metal batteries with zero excess lithium in theory, which theoretically have higher Energy density, but in actual use, lithium will be deposited unevenly in the current collector, resulting in dead lithium, resulting in low cycle life, and serious lithium dendrites, which will bring safety hazards, affect the performance of lithium batteries, and limit lithium battery life. battery application.
  • the present application discloses a current collector to alleviate or even solve the above-mentioned problem of uneven lithium deposition, avoid the generation of lithium dendrites, and improve its performance.
  • the present application provides a current collector, the current collector includes a first polymer layer, a metal layer and a second polymer layer stacked in sequence, and the current collector has Multiple through holes on opposite surfaces.
  • the application provides a current collector, including: a first polymer layer; a metal layer, the metal layer is located on one side of the first polymer layer; a second polymer layer, the second polymer layer is located on the The side of the metal layer away from the first polymer layer is directed from the first polymer layer to the direction of the second polymer layer, and the current collector has a plurality of through holes penetrating through the current collector .
  • the through-hole runs through the current collector, which is conducive to the effective infiltration of the current collector by the electrolyte and improves the electrochemical consistency inside the current collector.
  • the setting of the through-hole increases the specific surface area and internal space of the current collector. These internal The space accommodates the lithium precipitated during charge and discharge, and the metal layer is set in the middle, which can induce lithium to deposit on the inner metal layer, inhibit the generation of lithium dendrites, avoid the generation of dead lithium (deactivated lithium), and reduce the interface impedance and loss of active lithium.
  • the current collector provided by the present application can be directly used as a negative electrode to improve the electrochemical performance and safety of the negative electrode.
  • the current collector further includes a conductive layer, and the conductive layer is disposed on the inner sidewall of the through hole.
  • the through holes are distributed in an array.
  • the diameter of the through hole is less than or equal to 10 ⁇ m.
  • the thickness of the metal layer is less than or equal to 4 ⁇ m.
  • the thickness of the first polymer layer is 11 ⁇ m-26 ⁇ m.
  • the thickness of the second polymer layer is 11 ⁇ m-26 ⁇ m.
  • the current collector further includes a lithium-containing metal layer, and the lithium-containing metal layer is disposed in the metal layer.
  • the thickness of the lithium-containing metal layer is 10 nm-2 ⁇ m.
  • the current collector further includes a flame retardant layer, the flame retardant layer is disposed on the side of the first polymer layer away from the metal layer, and/or the flame retardant layer is disposed on the second polymer layer The side of the material layer facing away from the metal layer.
  • the thickness of the flame retardant layer is 10 nm-1 ⁇ m.
  • the first polymer layer has a lithium-supplementing material, and the mass proportion of the lithium-supplementing material in the first polymer layer is 0.1wt%-5wt%, and the first polymer layer deviates from the insulation on one side of the metal layer, and/or
  • the second polymer layer has a lithium-supplementing material, the mass proportion of the lithium-supplementing material in the second polymer layer is 0.1wt%-5wt%, and the second polymer layer is away from the metal One side of the layer is insulated,
  • the lithium supplement material includes at least one of Li-Mg, Li-Al, Li-Si, Li-Ag, Li-Au, Li-Sn, Li-In and Li-Ge alloys.
  • the present application also provides a method for preparing a current collector, the current collector comprising:
  • the first polymer film, the metal film and the second polymer film are sequentially stacked to form a first composite structure
  • the present application also provides a negative electrode, which includes the current collector prepared by the preparation method described in the first aspect or the second aspect.
  • the present application also provides an electrochemical energy storage device, which includes a positive electrode and the negative electrode described in the third aspect.
  • the porosity ⁇ of the current collector, the areal capacity C of the positive electrode, the thickness d of the current collector in the stacking direction, and the capacity-thickness constant k satisfy the formula:
  • FIG. 1 is a schematic top view of a current collector provided by an embodiment of the present application.
  • Fig. 2 is a schematic cross-sectional view along line I-I in Fig. 1 .
  • FIG. 3 is a schematic cross-sectional view of a current collector provided by another embodiment of the present application.
  • Figure 4 is a schematic cross-sectional view of a current collector provided in another embodiment of the present application.
  • FIG. 5 is a schematic cross-sectional view of a current collector provided by another embodiment of the present application.
  • FIG. 6 is a schematic cross-sectional view of a current collector provided by another embodiment of the present application.
  • Fig. 7 is a schematic diagram of the preparation flow of a current collector provided by an embodiment of the present application.
  • Fig. 8 is a schematic cross-sectional view of an electrochemical energy storage device provided by an embodiment of the present application.
  • FIG. 1 is a schematic top view of a current collector provided by an embodiment of the present application
  • FIG. 2 is a schematic cross-sectional view along line I-I in FIG. 1
  • the current collector 1 includes a first polymer layer 11, a metal layer 12, and a second polymer layer 13, and the first polymer layer 11, the metal layer 12, and the second polymer layer 13 are sequentially stacked, that is, the metal layer 12 is located on the first On one side of the polymer layer 11 , the second polymer layer 13 is located on the side of the metal layer 12 away from the first polymer layer 11 .
  • the current collector 1 has a plurality of through holes 14 penetrating through the current collector 1 , that is to say, it has a plurality of through holes 14 penetrating through opposite surfaces of the current collector 1 in the stacking direction.
  • the current collector 1 provided by the present application is provided with a through hole 14 that runs through the current collector 1, which facilitates the effective infiltration of the current collector 1 by the electrolyte and improves the electrochemical consistency inside the current collector 1; at the same time, the setting of the through hole 14
  • the specific surface area and internal space of the current collector 1 are improved, and these internal spaces accommodate the lithium precipitated during charging and discharging, and suppress the generation of lithium dendrites;
  • the stacked structure allows the metal layer 12 to be disposed inside the current collector 1, which can induce Lithium is deposited on the metal layer 12 inside the current collector 1, suppressing the generation of lithium dendrites, avoiding the generation of dead lithium (deactivated lithium), reducing the interface impedance, avoiding the loss of active lithium, and improving electrochemical performance and safety in use .
  • the current collector 1 Compared with the current collector with a single metal layer, the current collector 1 provided by the present application avoids the deposition of lithium on the surface of the current collector 1 by setting the first polymer layer 11 and the second polymer layer 13, effectively ensuring its performance and safety performance, while the setting of the through hole 14 further improves the performance, which is beneficial to its application.
  • the current collector 1 has through holes 14 , the first polymer layer 11 , the metal layer 12 and the second polymer layer 13 are all porous layer structures.
  • the material of the first polymer layer 11 can be selected from at least one of polyethylene, polypropylene, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, polyester and polyacrylonitrile species, the application does not limit this.
  • the material of the second polymer layer 13 can be selected from at least one of polyethylene, polypropylene, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, polyester and polyacrylonitrile, This application is not limited to this.
  • the first polymer layer 11 and the second polymer layer 13 are made of the same material.
  • the material of the first polymer layer 11 and the second polymer layer 13 may be, but not limited to, polyethylene terephthalate.
  • the thickness of the first polymer layer 11 is 11 ⁇ m-26 ⁇ m. That is, the thickness of the first polymer layer 11 in the stacking direction is 11 ⁇ m-26 ⁇ m. Further, the thickness of the first polymer layer 11 is 15 ⁇ m-23 ⁇ m. Specifically, the thickness of the first polymer layer 11 may be, but not limited to, 11 ⁇ m, 13 ⁇ m, 15 ⁇ m, 18 ⁇ m, 21 ⁇ m, 25 ⁇ m, 26 ⁇ m and the like. In some examples of the present application, the thickness of the second polymer layer 13 is 11 ⁇ m-26 ⁇ m. That is, the thickness of the second polymer layer 13 in the stacking direction is 11 ⁇ m-26 ⁇ m.
  • the thickness of the second polymer layer 13 is 15 ⁇ m-23 ⁇ m. Specifically, the thickness of the second polymer layer 13 may be, but not limited to, 12 ⁇ m, 14 ⁇ m, 17 ⁇ m, 23 ⁇ m, 24 ⁇ m and the like. In one embodiment, the thickness of the first polymer layer 11 and the thickness of the second polymer layer 13 are the same.
  • the first polymer layer 11 and the second polymer layer 13 has a lithium-supplementing material, that is to say, the first polymer layer 11 and/or the second polymer layer 13 has lithium supplement materials. Therefore, the consumed lithium is replenished during the charging and discharging process, and the energy density and cycle life are improved.
  • the lithium supplement material includes at least one of Li-Mg, Li-Al, Li-Si, Li-Ag, Li-Au, Li-Sn, Li-In and Li-Ge alloys. Thus, lithium supplementation can be effectively performed.
  • the mass proportion of the lithium-supplementing material in the first polymer layer 11 is 0.1wt%-5wt%.
  • the mass proportion of the lithium-supplementing material in the second polymer layer 13 is 0.1wt%-5wt%.
  • the use of the above-mentioned content of lithium-replenishing material is not only beneficial to lithium supplementation, but also does not affect the insulating properties of the first polymer layer 11 and the second polymer layer 13 .
  • the mass proportion of the lithium-replenishing material in the first polymer layer 11 can be, but not limited to, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt% or 4wt%, and the lithium-replenishing material is in the second polymer layer 11.
  • the mass proportion of the polymer layer 13 can be, but not limited to, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt% or 4wt%.
  • the electronic conductivity of the side of the first polymer layer 11 away from the metal layer 12 is relatively low, so as to ensure that metal lithium will not be preferentially deposited on the first polymer layer 11.
  • the surface of the polymer layer 11 avoids the generation of lithium dendrites and dead lithium, and at the same time prolongs the service life of the battery; when the second polymer layer 13 uses the above-mentioned content of lithium-supplementing materials, the second polymer layer 13 is away from the metal layer 12
  • the electronic conductance of one side of the battery is relatively low, so as to ensure that metal lithium will not be preferentially deposited on the surface of the second polymer layer 13, avoiding lithium dendrites and dead lithium, and prolonging the service life of the battery. That is to say, when the current collector has a lithium-supplementing material, the current collector can meet at least one of the following conditions:
  • the electronic conductivity of the side of the first polymer layer facing away from the metal layer is lower than the electronic conductivity of the side of the first polymer layer facing the metal layer;
  • the first polymer layer 11 has a lithium-supplementing material, and the side of the first polymer layer 11 away from the metal layer 12 is insulated.
  • the second polymer layer 13 has a lithium-supplementing material, and the side of the second polymer layer 13 away from the metal layer 12 is insulated.
  • the metal layer 12 provided inside the current collector 1 ensures the preferential deposition of lithium inside, avoids the generation of lithium dendrites, and is beneficial to the improvement of its electrochemical performance.
  • the material of the metal layer 12 includes at least one of copper, gold, silver, magnesium, zinc, titanium and nickel or stainless steel. Further, the material of the metal layer 12 includes at least one of copper, copper alloy, silver, titanium and nickel, or stainless steel. Specifically, the metal layer 12 may be, but not limited to, copper foil, copper alloy foil, stainless steel foil, silver foil, titanium foil or nickel foil. In one example, the metal layer 12 is copper foil or copper alloy foil.
  • the thickness of the metal layer 12 is less than or equal to 4 ⁇ m. That is, the thickness of the metal layer 12 in the stacking direction is less than or equal to 4 ⁇ m. Further, the thickness of the metal layer 12 is less than or equal to 3 ⁇ m. Specifically, the thickness of the metal layer 12 may be, but not limited to, 0.5 ⁇ m, 1 ⁇ m, 1.5 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m and the like.
  • the thickness of the metal layer 12 is smaller than the thickness of the first polymer layer 11 , and the thickness of the metal layer 12 is smaller than the thickness of the second polymer layer 13 . Therefore, the proportion of the metal layer 12 in the overall current collector 1 is small, the mass and volume ratio of the inactive components can be reduced, and the energy density of the current collector 1 can be improved; the setting of the through hole 14 will not affect the current collector too much The strength is beneficial to increase the pore diameter of the through hole 14 and the porosity of the current collector 1 .
  • the thickness of the metal layer 12 is less than or equal to 4 ⁇ m
  • the thickness of the first polymer layer 11 is 11 ⁇ m-26 ⁇ m
  • the thickness of the second polymer layer 13 is 11 ⁇ m-26 ⁇ m.
  • the current collector 1 has a plurality of through holes 14 , and the through holes 14 penetrate through two opposite surfaces of the current collector 1 in the stacking direction.
  • the direction indicated by the arrow is the stacking direction.
  • the vias 14 are distributed in an array.
  • the through holes 14 are evenly distributed in an array, which is beneficial to the uniform deposition of lithium precipitated during charging and discharging, avoiding excessive and prominent local lithium deposition, and further improving the safety performance of use.
  • the diameter of the through hole 14 is less than or equal to 10 ⁇ m. Further, the diameter of the through hole 14 is less than 8 ⁇ m. Specifically, the diameter of the through hole 14 may be, but not limited to, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 8 ⁇ m and the like.
  • the first polymer layer 11 has a first via sub-hole 141
  • the metal layer 12 has a second via sub-hole 142
  • the second polymer layer 13 has a third via sub-hole 143 .
  • the first sub-through hole 141 communicates with the third sub-through hole 143 through the corresponding second sub-through hole 142 to form the through hole 14 .
  • the first sub-through hole 141, the second sub-through hole 142, and the third sub-through hole 143 all have accommodating spaces, so that when the current collector 1 is infiltrated with the electrolyte, the electrolyte can more evenly infiltrate the current collector. 1, that is, the inner surfaces of the first sub-through hole 141 , the second sub-through hole 142 and the third sub-through hole 143 .
  • the aperture shape of the through hole 14 in the current collector 1 includes at least one of a cylindrical shape, a rectangular tubular shape, a cubic tubular shape, a trapezoidal cylindrical shape, and a triangular pyramid shape.
  • the application does not limit the aperture shape of the through hole 14 .
  • the cross section of the through hole 14 can be, but not limited to, polygonal, circular, oval, irregular, etc.
  • the longitudinal section of the through hole 14 can be, but not limited to, rectangular, trapezoidal, trapezoidal, conical, conical. shapes, irregular shapes, etc.
  • the cross section is the cross section of the through hole on the plane where the first and second polymer layers are located
  • the longitudinal section is the cross section of the through hole in the thickness direction of the current collector.
  • the inner sidewall of the through hole 14 is inclined, and the cross section of the through hole 14 gradually increases from the metal layer 12 to the first polymer layer 11, and the cross section of the through hole 14 increases from the metal layer 12 It gradually increases in the direction to the second polymer layer 13 , for example, may have a structure as shown in FIG. 3 .
  • the cross-section of the through hole along the plane where the first or second polymer layer is located gradually increases from the metal layer to the direction of the first polymer layer; or, the cross-section increases from the The metal layer gradually increases in the direction of the second polymer layer.
  • the above cross section of the through hole may satisfy one or both of the foregoing conditions. Therefore, the specific surface area of the through hole 14 is increased, which is beneficial to the deposition of lithium.
  • FIG. 1 and FIG. 2 together wherein the aperture shape of the through hole 14 is cylindrical.
  • FIG. 3 which is a schematic cross-sectional view of a current collector provided in another embodiment of the present application, wherein the longitudinal cross-sectional shape of the through hole 14 is trapezoidal.
  • the through hole 14 when the cross section of the through hole 14 is circular and the longitudinal section is trapezoidal, the through hole 14 has a trapezoidal cylindrical shape. Further, the longitudinal cross-section of the through hole 14 is trapezoid-like, where the short sides of two trapezoids intersect, and the cross-section of the through-hole 14 gradually increases from the metal layer 12 to both ends of the current collector 1 .
  • the cross-sectional area at the maximum aperture of the second sub-through hole 142 is less than or equal to the cross-sectional area at the minimum aperture of the first sub-through hole 141 and the third sub-through hole 143 .
  • the conductive substance is more easily deposited on the inner sidewalls of the first sub-through hole 141 , the second sub-through hole 142 and the third sub-through hole 143 .
  • FIG. 4 is a schematic cross-sectional view of a current collector provided in another embodiment of the present application.
  • the current collector 1 further includes a conductive layer 15 disposed on the inner sidewall of the through hole 14 . It can be understood that the provided conductive layer 15 does not block the through hole 14 , and the inside of the current collector 1 still has a hollow space.
  • metal lithium can be deposited in the inner space of the current collector 1, avoiding deposition on the surface of the current collector 1, effectively reducing the formation of dead lithium, and improving electrochemical performance.
  • the conductive layer 15 is formed by depositing or impregnating a conductive substance on the inner sidewall of the through hole 14 . Furthermore, conductive substances are deposited on the inner sidewalls of the first sub-through hole 141 , the second sub-through hole 142 and the third sub-through hole 143 , which can effectively reduce the generation of by-products, thereby prolonging the service life of the current collector 1 .
  • the material of the conductive layer 15 includes at least one of metal material, carbon material and conductive polymer material. Specifically, the material of the conductive layer 15 includes at least one of gold, silver, copper, nickel, iron, aluminum, germanium, tin, zinc, indium, vanadium, magnesium, cobalt, carbon, polyaniline and polypyrrole.
  • FIG. 5 is a schematic cross-sectional view of a current collector provided in another embodiment of the present application, wherein the current collector 1 further includes a lithium-containing metal layer 16 , and the lithium-containing metal layer 16 is disposed in the metal layer 12 .
  • the lithium-containing metal layer 16 may include at least one of lithium element and lithium alloy.
  • the lithium alloy includes at least one of Li-Ag, Li-Mg, Li-Zn, Li-AL, Li-Au, Li-Si, Li-Sn and Li-Ge alloys.
  • the lithium-containing metal layer 16 has a thickness of 10 nm-2 ⁇ m. Further, the thickness of the lithium-containing metal layer 16 is 100 nm-1.5 ⁇ m. Furthermore, the thickness of the lithium-containing metal layer 16 is 300nm-1000nm. Specifically, the thickness of the lithium-containing metal layer 16 may be, but not limited to, 100 nm, 400 nm, 500 nm, 800 nm, 1 ⁇ m, 1.5 ⁇ m, 1.8 ⁇ m, 2 ⁇ m, etc. In one embodiment, the lithium-containing metal layer 16 is disposed inside the metal layer 12 . That is, the lithium-containing metal layer 16 is covered by the metal layer 12 .
  • the metal layer 12 includes a first porous metal layer and a second porous metal layer, and the first porous metal layer, the lithium-containing metal layer 16 and the second porous metal layer are sequentially stacked. It should be noted that the through hole 14 also penetrates through the lithium-containing metal layer 16 of the flame retardant layer.
  • FIG. 6 is a schematic cross-sectional view of a current collector provided in another embodiment of the present application, wherein the current collector 1 further includes a flame-retardant layer 17, and the flame-retardant layer 17 is arranged at at least one of the following positions: the flame-retardant layer 17 is set On the side of the first polymer layer 11 facing away from the metal layer 12 , the flame retardant layer 17 is disposed on a side of the second polymer layer 13 facing away from the metal layer 12 . That is, the flame retardant layer 17 is disposed on the side of the first polymer layer 11 away from the metal layer 12 , and/or the flame retardant layer 17 is disposed on the side of the second polymer layer 13 away from the metal layer 12 .
  • the metal lithium has high activity, and it is easy to cause the combustion of the electrochemical energy storage device 2 when a short circuit occurs, causing a safety accident.
  • the flame retardant layer 17 can be heated and melted, can block the hole, and wrap the metal lithium deposited in the through hole 14, to avoid further contact between the metal lithium and the electrolyte to cause thermal runaway, and the melted flame retardant layer 17 can block the adjacent
  • the first sub-through holes 141 in the first polymer layer 11 and/or the second sub-through holes 142 in the second polymer layer 13 isolate ion channels, eliminate safety hazards, and improve use safety.
  • the melting point of the material of the flame-retardant layer 17 is 120°C-155°C.
  • the use of low melting point flame retardant materials is more conducive to flame retardancy. It should be noted that when the flame retardant layer 17 is disposed on the side of the first polymer layer 11 away from the metal layer 12, and/or the side of the second polymer layer 13 away from the metal layer 12, the through hole 14 also penetrates through the resistance The flame retardant layer 17; that is to say, the provided flame retardant layer 17 also has a plurality of holes, and the holes communicate with the first sub-through hole 141 and/or the third sub-through hole 143 correspondingly.
  • the material of the flame retardant layer 17 includes one or more of polyethylene wax, polypropylene wax and polyethylene oxide wax.
  • the thickness of the flame retardant layer 17 in order not to affect the overall thickness of the current collector 1, is small, and its thickness range can be but not limited to 10nm-1 ⁇ m, 50nm-0.8 ⁇ m, 100nm-0.7 ⁇ m or 200nm-0.5 ⁇ m ⁇ m etc.
  • the present application does not specifically limit the specific preparation method of the current collector 1 .
  • a preparation method of the current collector 1 provided in the present application will be illustrated.
  • FIG. 7 is a schematic flow chart of the preparation of a current collector provided by an embodiment of the present application.
  • the method for preparing the current collector 1 includes: steps S701, S702, S703, and S704.
  • steps S701, S702, S703, and S704 are as follows.
  • the sequential stacking of the first polymer film, the metal film and the second polymer film includes: depositing metal on the first polymer film to form a metal film; At least one of the extrusion-calendering processes forms a second polymer film on the metal film.
  • the sequential stacking of the first polymer film, the metal film and the second polymer film includes: providing a substrate, depositing metal on the substrate, and peeling off to form a metal film; At least one of deposition and melt extrusion calendering processes to form a first polymer film and a second polymer film on opposite surfaces of the metal film.
  • the deposition can be, but not limited to, magnetron sputtering, ion plating, vacuum evaporation and the like.
  • the deposition process parameters can be selected according to needs, which is not limited in this application.
  • the sequential stacking of the first polymer film, the metal film and the second polymer film includes installing the first polymer film in a vacuum magnetron sputtering coating machine, and vacuuming the cavity with a vacuum pump. pressure reaches 8 ⁇ 10 -2 Pa, and then a certain amount of argon gas is introduced to adjust the vacuum degree to 2 ⁇ 10 -1 Pa, and the surface ion source cleaning is performed on the first polymer membrane, and the cleaning time is 5min-15min.
  • the metal plating power supply After completion, turn off the power supply of the ion source; start the metal plating power supply to magnetron sputter the metal film, the sputtering time of the metal film is 5min-100min, and obtain a metal film with a thickness less than or equal to 4 ⁇ m.
  • the protective film may be, but not limited to, at least one of transparent glue, engineering paper, and plastic wrap.
  • S703 Forming a plurality of through holes on the second composite structure, the through holes passing through two opposite surfaces of the second composite structure in a stacking direction.
  • the via hole 14 is formed by forming a plurality of first sub-via holes 141 in the first polymer film to form the first polymer layer 11, and forming a plurality of second sub-via holes 142 in the metal film to form In the metal layer 12 , a plurality of third sub-vias 143 are formed in the second polymer film to form the second polymer layer 13 .
  • a plurality of through holes are formed on the second composite structure by an ultrafast laser.
  • the method for preparing the current collector 1 further includes depositing a conductive substance on the inner sidewall of the through hole 14 to form a conductive layer 15 .
  • a conductive substance on the inner sidewall of the through hole 14 to form a conductive layer 15 .
  • thermal evaporation sputtering, magnetron sputtering or dipping methods can be used to arrange the conductive substance on the inner sidewall of the through hole 14 to form the conductive layer 15, such as the first sub-through hole 141, the second sub-through hole On the inner wall of the hole 142 and the third sub-through hole 143 .
  • the conductive substance can be partially deposited on the inner sidewalls of the first sub-through hole 141, the second sub-through hole 142 and the third sub-through hole 143, so as to avoid excessively long time.
  • the present application also provides a negative electrode 22, and the negative electrode 22 includes the current collector 1 in any one of the above-mentioned embodiments.
  • the current collector 1 can be directly used as the negative electrode 22, and the negative electrode 22 does not need to be provided with a negative electrode active material layer.
  • the negative electrode 22 is a lithium-free negative electrode.
  • the current collector 1 provided by this application is used as the negative electrode 22, the negative electrode 22 can be greatly improved. electrochemical performance and safety performance.
  • the present application also provides an electrochemical energy storage device 2, and the electrochemical energy storage device 2 includes the above-mentioned negative electrode 22 .
  • FIG. 8 is a schematic cross-sectional view of an electrochemical energy storage device provided in an embodiment of the present application.
  • the electrochemical energy storage device 2 includes a positive electrode 21 and a negative electrode 22 .
  • the current collector 1 serves as the negative electrode 22 of the electrochemical energy storage device 2 .
  • the electrochemical energy storage device 2 is a lithium-free negative electrode-lithium battery, that is, a negative electrode-free battery.
  • the electrochemical energy storage device 2 can also be other types of batteries. This application is not limited to this.
  • the porosity ⁇ of the current collector 1, the areal capacity C of the positive electrode 21, the thickness d of the current collector 1 in the stacking direction, and the capacity-thickness constant k satisfy the formula:
  • k 5 ⁇ 10 ⁇ 4 cm 3 /mAh.
  • the electrochemical energy storage device 2 includes a positive electrode 21 and a negative electrode 22
  • the current collector 1 serves as the negative electrode 22 of the electrochemical energy storage device 2
  • the porosity ⁇ of the current collector 1 refers to the percentage value of the total volume of the through holes 14 to the total volume of the current collector 1
  • the areal capacity of the positive electrode 21 refers to the total number of electrons that can be released per unit surface area of the positive electrode 21 of the electrochemical energy storage device 2 .
  • the higher porosity can ensure that the space required for lithium deposition can be satisfied when the thickness of the current collector 1 is relatively low, avoiding volume expansion caused by disordered lithium deposition, and improving the safety performance of the current collector 1 . Further, ⁇ 60%, C ⁇ 6mAh/cm 2 .
  • the positive electrode 21 includes a positive electrode current collector and a positive electrode active material layer.
  • the material of the positive electrode active material layer includes LiFe a Mn b M c PO 4 , Li 3 V 2 (PO 4 ) 3 , Li 3 V 3 (PO 4 ) 3 , LiNi 0.5 - d Mn 1.5 - e
  • N d + e O 4 , LiVPO 4 F, Li 1 + f L 1 - g - h H g R h O 2 , Li 2 CuO 2 , Li 5 FeO 4 ; where, 0 ⁇ a ⁇ 1, 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1, a+b+c 1, M is at least one of Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo; -0.1 ⁇ d ⁇ 0.5, 0 ⁇ e ⁇ 1.5, N is at least one of Li, Co, Fe, Al, Mg, Ca, Ti, Mo, Cr, Cu, Zn; -0.1 ⁇ d ⁇ 0.5, 0
  • the material of the positive electrode active material layer includes LiAl 0.05 Co 0.15 Ni 0.80 O 2 , LiNi 0.80 Co 0.10 Mn 0.10 O 2 , LiNi 0.90 Co 0.05 Mn 0.05 O 2 , LiNi 0.60 Co 0.20 Mn 0.20 O 2 , At least one of LiCoO 2 , LiMn 2 O 4 , LiFePO 4 , LiMnPO 4 , LiNiPO 4 , LiCoPO 4 , LiNi 0.5 Mn 1.5 O 4 , and Li 3 V 3 (PO 4 ) 3 .
  • the material of the positive electrode active material layer includes at least one of lithium sulfide, lithium-intercalated V 2 O 5 , lithium-intercalated MnO 2 , lithium-intercalated TiS 2 and lithium-intercalated FeS 2 .
  • the electrochemical energy storage device 2 further includes a separator 23 disposed between the positive electrode 21 and the negative electrode 22 .
  • the separator 23 is used to separate the positive electrode 21 and the negative electrode 22 of the electrochemical energy storage device 2 , and the application does not limit the material of the separator 23 .
  • the electrochemical energy storage device 2 provided in the embodiment of the present application contains the above-mentioned current collector 1, and the current collector enables the electrochemical energy storage device 2 to have high energy density, high charge and discharge capacity, and it is not easy to generate lithium dendrites and has high safety performance. , The cycle life is longer.
  • a method for preparing a current collector comprising:
  • a transparent adhesive protective film is provided on the surface of the first PET film and the second PET film away from the metal copper foil to obtain a composite structure; an ultrafast laser (wavelength 355nm) is used to form a plurality of channels arranged in an array on the composite structure. Pores, the through-holes penetrate the composite structure and face the two surfaces in the stacking direction, the diameter of the through-holes is 10 ⁇ m, and a porous composite structure is obtained;
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as Example 1, except that the thickness of the first PET film and the second PET film are 16.75 ⁇ m, and the porosity and pore diameter are 80% and 10 ⁇ m, respectively, to obtain the current collector Z2.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as Example 1, except that the thickness of the first PET film and the second PET film are 28 ⁇ m, and the porosity and pore size are 50% and 5 ⁇ m, respectively, to obtain the current collector Z3.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as in Example 1, except that the protective film of transparent glue is directly removed after step (3), and the step (4) is not performed to obtain the current collector Z4.
  • a method for preparing a current collector comprising:
  • Embodiment 2 It is roughly the same as that of Embodiment 1, except that a plurality of through holes are arranged in disorder to obtain a current collector Z5.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as in Example 1, except that the thickness of the metal copper foil is 8 ⁇ m, and the thickness of the first PET film and the second PET film are 16 ⁇ m, and the current collector Z6 is obtained.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as in Example 1, except that the porosity and pore size are 50% and 10 ⁇ m, respectively, and the current collector Z7 is obtained.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as Example 1, except that the surface of the first PET film facing away from the metal copper foil and the surface of the second PET film facing away from the metal copper foil are provided with a porous polypropylene wax flame-retardant layer to obtain a current collector Z8.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as Example 1, except that there are magnesium-aluminum alloy particles in the second PET film, the mass ratio of the magnesium-aluminum alloy particles in the second PET film is 1 wt%, and the surface of the second PET film is insulated , to obtain the current collector Z9.
  • a method for preparing a current collector comprising:
  • Example 2 It is roughly the same as in Example 1, except that the porosity and pore size are 80% and 10 ⁇ m, respectively, and the current collector Z10 is obtained.
  • step (4) the transparent adhesive protective film on the surface is peeled off first, and then the same evaporation process is performed to obtain the current collector DZ1.
  • Example 2 Roughly the same as Example 1, the difference is that the processing time of each laser hole in step (3) is reduced by half, and a non-through hole array porous structure is obtained, with a pore diameter of 10 ⁇ m. Due to the non-through holes, the porosity is 67.5% , to obtain the current collector DZ2.
  • a vacuum mixer to mix 49g of positive electrode active material (LiFePO 4 ), 0.5g of conductive agent (acetylene black) and 0.5g of binder (polyvinylidene fluoride, PVDF) in NMP to form a stable and uniform slurry, wherein, The stirring speed is 1000rpm, and the time is 12h; then the obtained slurry is coated on the aluminum sheet of the current collector, and the surface density is controlled to be 220g/m 2 , then dried at 80°C, and then cut into positive electrodes with a size of 61 ⁇ 72mm and then dried at 80°C, and the positive electrode sheet was obtained after being pressed by a roller press, and one of them was cut into pieces with a diameter of 13mm to assemble a button battery for capacity calibration, and the rated capacity was 6mAh/cm 2 .
  • positive electrode active material LiFePO 4
  • conductive agent acetylene black
  • binder polyvinylidene fluoride
  • the current collector Z or DZ obtained in the above examples and comparative examples is directly used as the negative electrode, and is respectively stacked with the separator and the positive electrode sheet layer by layer to form a battery, and 2.2mL/Ah electrolyte is added dropwise, and the electrolyte is 1wt% LiNO 3 Dissolved in ethylene glycol dimethyl ether (DME) in 4MLiFSI, and then packaged to obtain batteries S1-S10 and DS1-DS2, respectively.
  • DME ethylene glycol dimethyl ether
  • Table 1 The data of the average initial discharge capacity of the battery and the thickness change rate table before and after the battery cycle
  • Impedance (EIS) test Take another two batteries S1-S10 and DS1-DS2 each for injection and let them stand still, and perform impedance tests every 0.5h (amplitude 5mV, frequency 1000-0.01Hz), the experimental results are as follows Table 2 shows.
  • mass energy density (first discharge capacity * first discharge average voltage) / battery quality
  • Volumetric energy density (the nth discharge capacity * nth discharge average voltage) / battery volume;
  • the above-mentioned battery mass is the mass of the battery cell excluding the case, cover plate and parts arranged on the case and cover plate;
  • the cell volume of the components is the mass of the battery cell excluding the case, cover plate and parts arranged on the case and cover plate;
  • Lithium metal deposition experiment take another 2 batteries S1-S10 and DS1-DS2 for the first lithium deposition. At 25°C, the battery was charged to 3.8V at a current density of 0.6mA/cm 2 , and the battery was disassembled to observe the deposition position of lithium. The experimental results are shown in Table 4.
  • the comparative example has mass energy density and volumetric energy density that are basically equivalent to those of the examples at the initial stage, lithium metal is easy to deposit on the surface of the negative electrode in the comparative example, and the capacity decays quickly after cycling. , the volume of the battery expands greatly, and the volume energy density is the lowest in the late cycle.
  • the battery provided in the embodiment of the present application contains the current collector provided in the present application, so that the battery has high energy density, high charge and discharge capacity, and is not easy to produce lithium dendrites. Safety performance High, long cycle life.

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Abstract

本申请提出了集流体及制备的方法、负极和电化学储能装置。该集流体包括：第一聚合物层；金属层，所述金属层位于所述第一聚合物层的一侧；第二聚合物层，所述第二聚合物层位于所述金属层远离所述第一聚合物层的一侧，自所述第一聚合物层指向所述第二聚合物层的方向上，所述集流体具有贯穿所述集流体的多个通孔。

Description

集流体及制备的方法、负极和电化学储能装置 技术领域
本申请涉及储能技术领域，尤其是涉及集流体及制备的方法、负极和电化学储能装置。
背景技术
锂电池具有高能量密度，良好的循环稳定性、安全性等特点，在手机、电脑、汽车和电网储能等多个领域广泛使用。锂金属电池使用的锂箔会带来较高的成本和电池制成过程的安全隐患，因此激发仅使用集流体作为负极材料，即理论上零过量锂的锂金属电池，理论上具有更高的能量密度，但是在实际使用时锂会在集流体不均匀沉积，产生死锂导致循环寿命低，并还会产生严重的锂枝晶而带来安全隐患，影响锂电池的使用性能，限制了锂电池的应用。
发明内容
本申请公开了一种集流体，以缓解甚至解决上述锂沉积不均匀的问题，避免锂枝晶的产生，提高其使用性能。
第一方面，本申请提供了一种集流体，所述集流体包括依次层叠设置的第一聚合物层、金属层及第二聚合物层，所述集流体具有贯穿所述集流体在层叠方向上相对两个表面的多个通孔。
申请提供了一种集流体，包括：第一聚合物层；金属层，所述金属层位于所述第一聚合物层的一侧；第二聚合物层，所述第二聚合物层位于所述金属层远离所述第一聚合物层的一侧，自所述第一聚合物层指向所述第二聚合物层的方向上，所述集流体具有贯穿所述集流体的多个通孔。
在本申请中，通孔贯穿集流体，有利于集流体被电解液有效的浸润，提高集流体内部的电化学一致性，同时通孔的设置提高了集流体的比表面积以及内部空间，这些内部空间容纳充放电过程中析出的锂，并且金属层设置在中间，可以诱导锂沉积在内部的金属层上，抑制锂枝晶的产生，避免产生死锂(失去活性的锂)，减小界面阻抗和活性锂的损失。本申请提供的集流体可以直接作为负极使用，提高负极的电化学性能和安全性。
其中，所述集流体还包括导电层，所述导电层设置在于所述通孔的内侧壁上。
其中，所述通孔呈阵列形式分布。
其中，所述通孔的孔径小于或等于10μm。
其中，所述金属层的厚度小于或等于4μm。
其中，所述第一聚合物层的厚度为11μm-26μm。
其中，所述第二聚合物层的厚度为11μm-26μm。
其中，所述集流体还包括含锂金属层，所述含锂金属层设置于所述金属层内。
其中，所述含锂金属层的厚度为10nm-2μm。
其中，所述集流体还包括阻燃层，所述阻燃层设置于所述第一聚合物层背离所述金属层的一侧，和/或所述阻燃层设置于所述第二聚合物层背离所述金属层的一侧。
其中，所述阻燃层的厚度为10nm-1μm。
其中，所述第一聚合物层中具有补锂材料，所述补锂材料在所述第一聚合物层中的质量占比为0.1wt％-5wt％，所述第一聚合物层背离所述金属层的一侧绝缘，和/或
所述第二聚合物层中具有补锂材料，所述补锂材料在所述第二聚合物层中的质量占比为0.1wt％-5wt％，所述第二聚合物层背离所述金属层的一侧绝缘，
所述补锂材料包括Li-Mg、Li-Al、Li-Si、Li-Ag、Li-Au、Li-Sn、Li-In和Li-Ge合金中的至少一种。
第二方面，本申请还提供了一种集流体的制备方法，集流体包括：
第一聚合物膜、金属膜和第二聚合物膜依次层叠设置，形成第一复合结构；
将第一保护膜设置于所述第一聚合物膜背离所述金属膜的一侧表面，将第二保护膜设置于所述第二聚合物膜背离所述金属膜的一侧表面，形成第二复合结构；
在所述第二复合结构上成型多个通孔，所述通孔贯穿所述第二复合结构在所述层叠方向上的相对两个表面；
去除所述第一保护膜和所述第二保护膜，得到集流体。
第三方面，本申请还提供了一种负极，所述负极包括第一方面所述的或第二方面所述的制备方法制得的集流体。
第四方面，本申请还提供了一种电化学储能装置，所述电化学储能装置包括正极和第三方面所述的负极。
其中，所述集流体的孔隙率β、所述正极的面容量C、所述集流体在层叠方向上的厚度d和容量-厚度常数k满足公式：
Figure PCTCN2022095943-appb-000001
所述β≥50％，所述C≥5mAh/cm 2，所述k＝5×10 -4cm 3/mAh。
附图说明
为了更清楚的说明本申请实施方式中的技术方案，下面将对实施方式中所需要使用的 附图作简单的介绍，显而易见的，下面描述中的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本申请一实施方式提供的集流体俯视示意图。
图2为图1中沿I-I线的剖视示意图。
图3为本申请另一实施方式提供的集流体剖视示意图。
图4为本申请另一实施方式提供的集流体剖视示意图
图5为本申请另一实施方式提供的集流体剖视示意图。
图6为本申请另一实施方式提供的集流体剖视示意图。
图7为本申请一实施方式提供的集流体制备流程示意图。
图8为本申请一实施方式提供的电化学储能装置剖视示意图。
附图标号说明：
集流体-1，第一聚合物层-11，金属层-12，第二聚合物层-13，通孔-14，第一子通孔-141，第二子通孔-142，第三子通孔-143，导电层-15，含锂金属层-16，阻燃层-17，电化学储能装置-2，正极-21，负极-22，隔膜-23。
具体实施方式
下面将结合本申请实施方式中的附图，对本申请实施方式中的技术方案进行清楚、完整的描述，显然，所描述的实施方式仅是本申请一部分实施方式，而不是全部的实施方式。基于本申请中的实施方式，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施方式，都属于本申请保护的范围。
本申请提供了一种集流体1，请一并参阅图1及图2，图1为本申请一实施方式提供的集流体俯视示意图；图2为图1中沿I-I线的剖视示意图。集流体1包括第一聚合物层11、金属层12及第二聚合物层13，第一聚合物层11、金属层12及第二聚合物层13依次层叠设置，即金属层12位于第一聚合物层11的一侧，第二聚合物层13位于金属层12远离第一聚合物层11的一侧。集流体1具有贯穿集流体1的多个通孔14，也即是说，其在层叠方向上具有贯穿集流体1相对两个表面的多个通孔14。
本申请提供的集流体1中设置有贯穿集流体1的通孔14，其有利于集流体1被电解液有效的浸润，提高集流体1内部的电化学一致性；同时，通孔14的设置提高了集流体1的比表面积以及内部空间，这些内部空间容纳充放电过程中析出的锂，抑制锂枝晶的产生；层叠设置的结构，使得金属层12设置于集流体1的内部，可以诱导锂沉积在集流体1内部的金属层12上，抑制锂枝晶的产生，避免产生死锂(失去活性的锂)，减小界面阻抗，避 免活性锂的损失，提高电化学性能和使用安全性。相较于单独金属层的集流体，本申请提供的集流体1中通过设置第一聚合物层11和第二聚合物层13，避免了锂在集流体1表面沉积，有效保证了其使用性能和安全性能，同时通孔14的设置进一步提高了使用性能，有利于其应用。
可以理解的，由于集流体1具有通孔14，因此第一聚合物层11、金属层12及第二聚合物层13均为多孔层结构。
在本申请的一些示例中，第一聚合物层11的材料可以选自聚乙烯、聚丙烯、聚酰亚胺、聚四氟乙烯、聚偏氟乙烯、聚酯和聚丙烯腈中的至少一种，本申请对此不加以限制。在另一些示例中，第二聚合物层13的材料可以选自聚乙烯、聚丙烯、聚酰亚胺、聚四氟乙烯、聚偏氟乙烯、聚酯和聚丙烯腈中的至少一种，本申请对此不加以限制。在一示例中，第一聚合物层11和第二聚合物层13的材料相同。具体的，第一聚合物层11及第二聚合物层13的材料可以但不限于为聚对苯二甲酸乙二醇酯。
在本申请的一些示例中，第一聚合物层11的厚度为11μm-26μm。即第一聚合物层11在层叠方向上的厚度为11μm-26μm。进一步的，第一聚合物层11的厚度为15μm-23μm。具体的，第一聚合物层11的厚度可以但不限于为11μm、13μm、15μm、18μm、21μm、25μm、26μm等。在本申请的一些示例中，第二聚合物层13的厚度为11μm-26μm。即第二聚合物层13在层叠方向上的厚度为11μm-26μm。进一步的，第二聚合物层13的厚度为15μm-23μm。具体的，第二聚合物层13的厚度可以但不限于为12μm、14μm、17μm、23μm、24μm等。在一实施例中，第一聚合物层11的厚度和第二聚合物层13的厚度相同。
在本申请的一些示例中，第一聚合物层11和第二聚合物层13中的至少之一处具有补锂材料，也即是说第一聚合物层11和/或第二聚合物层13中具有补锂材料。从而使得在充放电过程中补充消耗的锂，提高能量密度和循环寿命。进一步的，补锂材料包括Li-Mg、Li-Al、Li-Si、Li-Ag、Li-Au、Li-Sn、Li-In和Li-Ge合金中的至少一种。从而可以有效进行锂的补充。在一示例中，补锂材料在第一聚合物层11中的质量占比为0.1wt％-5wt％。在另一示例中，补锂材料在第二聚合物层13中的质量占比为0.1wt％-5wt％。采用上述含量的补锂材料，既有利于锂的补充，又不会影响第一聚合物层11、第二聚合物层13的绝缘性能。具体的，补锂材料在第一聚合物层11中的质量占比可以但不限于为0.1wt％、0.5wt％、1wt％、2wt％、3wt％或4wt％等，补锂材料在第二聚合物层13中的质量占比可以但不限于为0.1wt％、0.5wt％、1wt％、2wt％、3wt％或4wt％等。在本申请中，第一聚合物层11采用上述含量的补锂材料时，第一聚合物层11背离金属层12的一侧电子电导相对较低，从而保证金属锂不会优先沉积在第一聚合物层11的表面，避免产生锂枝晶和死锂，同时还延长了电池的使用寿命；第二聚合物层13采用上述含量的补锂材料时，第二聚合物层13背离金属层12的 一侧电子电导相对较低，从而保证金属锂不会优先沉积在第二聚合物层13的表面，避免产生锂枝晶和死锂，同时还延长了电池的使用寿命。也即是说，该集流体具有补锂材料时，该集流体可满足以下条件的至少之一：
(1)第一聚合物层背离所述金属层的一侧的电子电导率，低于所述第一聚合物层朝向所述金属层一侧的电子电导率；和
(2)所述第二聚合物层背离所述金属层的一侧的电子电导率，低于所述第二聚合物层朝向所述金属层一侧的电子电导率。
在一示例中，第一聚合物层11中具有补锂材料，第一聚合物层11背离金属层12的一侧绝缘。在另一示例中，第二聚合物层13中具有补锂材料，第二聚合物层13背离金属层12的一侧绝缘。
在本申请中，集流体1内部设置的金属层12，保证了锂在内部的优先沉积，避免了锂枝晶的产生，有利于其电化学性能的提升。
在本申请的一些示例中，金属层12的材质包括铜、金、银、镁、锌、钛和镍中的至少一种或不锈钢。进一步的，金属层12的材质包括铜单质、铜合金、银、钛和镍中的至少一种或不锈钢。具体的，金属层12可以但不限于为铜箔、铜合金箔、不锈钢箔、银箔、钛箔或镍箔。在一示例中，金属层12为铜箔或铜合金箔。
在本申请的一些示例中，金属层12的厚度小于或等于4μm。即金属层12在层叠方向上的厚度小于或等于4μm。进一步的，金属层12的厚度小于或等于3μm。具体的，金属层12的厚度可以但不限于为0.5μm、1μm、1.5μm、2μm、3μm、4μm等。
在本申请的一些示例中，金属层12的厚度小于第一聚合物层11的厚度，金属层12的厚度小于第二聚合物层13的厚度。从而使得金属层12在整体集流体1中的占比较少，可以降低非活性成分的质量和体积占比，提升集流体1的能量密度；还使得通孔14的设置不会过多影响集流体的强度，有利于提高通孔14的孔径以及集流体1的孔隙率。在一实施例中，金属层12的厚度小于等于4μm，第一聚合物层11的厚度为11μm-26μm，第二聚合物层13的厚度为11μm-26μm。
在本申请中，集流体1具有多个通孔14，通孔14贯穿集流体1在层叠方向上的相对两个表面。请参阅图2，在一实施方式中，箭头所指示的方向为层叠方向。
在一些示例中，请再次参阅图1，通孔14呈阵列形式分布。通孔14呈阵列均匀分布，有利于在充放电过程中析出的锂均匀沉积，避免局部锂沉积过多而突出，进一步提高使用安全性能。
在一些示例中，通孔14的孔径小于或等于10μm。进一步的，通孔14的孔径小于8μm。具体的，通孔14的孔径可以但不限于为3μm、4μm、5μm、6μm、8μm等。通过设置上述 小孔径的通孔14，进一步保证电解液缓慢通过通孔14，保证集流体1很好的浸润在电解液中，进一步提升电化学性能的一致性。
在一些示例中，如图2所示，第一聚合物层11具有第一子通孔141，金属层12具有第二子通孔142，第二聚合物层13具有第三子通孔143。第一子通孔141与第三子通孔143通过对应的第二子通孔142相连通，以形成通孔14。具体的，第一子通孔141、第二子通孔142及第三子通孔143内均具有容置空间，使得在集流体1浸润电解液时，电解液能够更加均匀的浸润至集流体1的内部，即第一子通孔141、第二子通孔142及第三子通孔143的内表面。
在一些示例中，集流体1中通孔14的孔径形状包括圆柱形、长方管形、立方管形、梯形圆柱形、三角锥形中的至少一种。具体的，只要不影响第一子通孔141与第三子通孔143通过对应的第二子通孔142相连通，本申请对通孔14的孔径形状不作限制。具体的，通孔14的横截面可以但不限于为多边形、圆形、椭圆形、不规则形状等，通孔14的纵截面可以但不限于为长方形、梯形、类梯形、圆锥形、类圆锥形、不规则形状等。此处需要特别说明的是，横截面即为通孔在第一、第二聚合物层所在平面的截面，纵截面即为通孔在集流体厚度方向上的截面。在一示例中，通孔14的内侧壁为倾斜状，且通孔14的横截面从金属层12至第一聚合物层11的方向上逐渐增大，通孔14的横截面从金属层12至第二聚合物层13的方向上逐渐增大，例如可以具有如图3中所示出的结构。也即是说，通孔沿所述第一或第二聚合物层所在平面的截面，自所述金属层指向所述第一聚合物层的方向上逐渐增大；或者，该截面自所述金属层指向所述第二聚合物层的方向上逐渐增大。通孔的上述截面可以满足前述条件的一个或两个。从而提高通孔14的比表面积，有利于锂的沉积。请一并参阅图1和图2，其中通孔14的孔径形状为圆柱形。请参阅图3，为本申请另一实施方式提供的集流体剖视示意图，其中通孔14的孔径纵截面形状为类梯形。在一示例中，当通孔14的横截面为圆形，纵截面为类梯形时，通孔14为梯形圆柱形。进一步的，通孔14的孔径纵截面形状为类梯形，类梯形为两个梯形的短边相交，且通孔14的横截面由金属层12向集流体1的两端逐渐增大。在本实施方式中，如图3所示，第二子通孔142的最大孔径处的横截面积小于或等于第一子通孔141及第三子通孔143的最小孔径处的横截面积。可以理解的，此种设置方式使得集流体1具有导电层15时，导电物质更容易沉积到第一子通孔141、第二子通孔142及第三子通孔143的内侧壁上。
在本申请的一些示例中，请参阅图4，为本申请另一实施方式提供的集流体剖视示意图，集流体1还包括导电层15，导电层15设置于通孔14的内侧壁上。可以理解的，设置的导电层15并未堵塞通孔14，集流体1的内部仍然具有镂空的空间。通过在通孔14中设置导电层15，从而使得金属锂可以沉积在集流体1的内部空间中，避免在集流体1的表面沉积， 有效降低死锂的形成，提升电化学性能。
在本申请的一些示例中，通过在通孔14的内侧壁上沉积或浸渍导电物质，形成导电层15。进一步的，第一子通孔141、第二子通孔142及第三子通孔143的内侧壁沉积有导电物质，可以有效的降低副产物产生的现象，从而延长集流体1的使用寿命。在一实施例中，导电层15的材质包括金属材料、碳材料和导电聚合物材料中的至少一种。具体的，导电层15的材质包括金、银、铜、镍、铁、铝、锗、锡、锌、铟、钒、镁、钴、碳、聚苯胺和聚吡咯中的至少一种。
请参阅图5，为本申请另一实施方式提供的集流体剖视示意图，其中集流体1还包括含锂金属层16，含锂金属层16设置于金属层12内。通过设置含锂金属层16，可以补充电解液与沉积锂之间反应消耗的锂，从而提升能量密度和循环寿命。在一实施例中，含锂金属层16的材质可以包括锂单质和锂合金中的至少一种。具体的，锂合金包括Li-Ag、Li-Mg、Li-Zn、Li-AL、Li-Au、Li-Si、Li-Sn和Li-Ge合金中的至少一种。在一实施例中，含锂金属层16的厚度为10nm-2μm。进一步的，含锂金属层16的厚度为100nm-1.5μm。更进一步的，含锂金属层16的厚度为300nm-1000nm。具体的，含锂金属层16的厚度可以但不限于为100nm、400nm、500nm、800nm、1μm、1.5μm、1.8μm、2μm等。在一实施方式中，含锂金属层16设置方式在金属层12内部。也就是说，含锂金属层16被金属层12包覆。在另一实施方式中，金属层12包括第一多孔金属层和第二多孔金属层，第一多孔金属层、含锂金属层16和第二多孔金属层依次层叠设置。需要说明的是，通孔14同样贯穿阻燃层含锂金属层16。
请参阅图6，为本申请另一实施方式提供的集流体剖视示意图，其中集流体1还包括阻燃层17，阻燃层17设置于以下位置的至少之一处：阻燃层17设置于第一聚合物层11背离金属层12的一侧，阻燃层17设置于第二聚合物层13背离金属层12的一侧。也即是阻燃层17设置于第一聚合物层11背离金属层12的一侧，和/或阻燃层17设置于第二聚合物层13背离金属层12的一侧。集流体1在电化学储能装置2中使用时，金属锂活性高，在发生短路情况时容易引起电化学储能装置2的燃烧，造成安全事故，通过设置阻燃层17，在短路发生的初期，阻燃层17可以受热熔化，可以堵住孔洞，并包裹通孔14中沉积的金属锂，避免金属锂与电解液的进一步接触引发热失控，并且熔化的阻燃层17可以堵塞临近的第一聚合物层11中的第一子通孔141，和/或第二聚合物层13中的第二子通孔142，隔绝离子通道，解除安全隐患，提高使用安全性。进一步的，阻燃层17的材料的熔点为120℃-155℃。采用低熔点阻燃材料更有利于进行阻燃。需要说明的是，当阻燃层17设置于第一聚合物层11背离金属层12的一侧，和/或第二聚合物层13背离金属层12的一侧时，通孔14同样贯穿阻燃层17；也就是说，设置的阻燃层17上也具有多个孔洞，孔洞与第一子通孔141和/ 或第三子通孔143对应连通。在本实施方式中，阻燃层17的材料包括聚乙烯蜡、聚丙烯蜡和聚氧化乙烯蜡中的一种或多种。在本实施方式中，为了不影响集流体1的整体厚度，阻燃层17的厚度较小，其厚度范围可以但不限于为10nm-1μm、50nm-0.8μm、100nm-0.7μm或200nm-0.5μm等。
本申请对集流体1的具体制备方法不作特殊限定，接下来，将举例说明本申请提供的一种集流体1的制备方法。
请参阅图7，为本申请一实施方式提供的集流体制备流程示意图。集流体1制备方法包括：步骤S701、S702、S703、S704，步骤S701、S702、S703、S704的详细介绍如下。
S701：第一聚合物膜、金属膜和第二聚合物膜依次层叠设置，形成第一复合结构。
在一实施方式中，第一聚合物膜、金属膜和第二聚合物膜依次层叠设置包括：在第一聚合物膜上沉积金属，形成金属膜；再通过液相涂覆、原子沉积和熔融挤出压延工艺中的至少一种，在金属膜上成型第二聚合物膜。在另一实施方式中，第一聚合物膜、金属膜和第二聚合物膜依次层叠设置包括：提供基材，在基材上沉积金属，剥离形成金属膜；再通过液相涂覆、原子沉积和熔融挤出压延工艺中的至少一种，在金属膜的相对两个表面成型第一聚合物膜和第二聚合物膜。具体的，沉积可以但不限于通过磁控溅射、离子镀、真空蒸镀等。具体的，沉积的工艺参数可以根据需要进行选择，本申请对此不作限定。在一实施例中，第一聚合物膜、金属膜和第二聚合物膜依次层叠设置包括将第一聚合物膜安装在真空磁控溅射镀膜机中，用真空泵抽真空使腔体的真空度到达8×10 -2Pa，再通入一定的氩气进行调节，使真空度达到2×10 -1Pa，对第一聚合物膜进行表面离子源清洗，清洗时间为5min-15min，清洗完成后，关闭离子源电源；启动镀金属电源进行磁控溅射金属膜，溅射金属膜的时间为5min-100min，得到厚度小于或等于4μm的金属膜。
S702：将第一保护膜设置于第一聚合物膜背离金属膜的一侧表面，将第二保护膜设置于第二聚合物膜背离金属膜的一侧表面，形成第二复合结构。
在本实施方式中，保护膜可以但不限于为透明胶、工程纸、保鲜膜中的至少一种。
S703：在第二复合结构上成型多个通孔，通孔贯穿第二复合结构在层叠方向上的相对两个表面。
在本实施方式中，通孔14通过在第一聚合物膜形成多个第一子通孔141，以形成第一聚合物层11，在金属膜形成多个第二子通孔142，以形成金属层12，在第二聚合物膜形成多个第三子通孔143，以形成第二聚合物层13。在本实施方式中，通过超快激光在第二复合结构上成型多个通孔。
S704，去除第一保护膜和第二保护膜，得到集流体。
在本实施方式中，集流体1的制备方法还包括在通孔14的内侧壁上沉积导电物质，形成 导电层15。具体的，可以采用热蒸发溅射、磁控溅射或浸渍的方法将导电物质设置在通孔14的内侧壁上，形成导电层15，如设置在第一子通孔141、第二子通孔142及第三子通孔143的内侧壁上。需要说明的是，可以通过控制沉积导电物质的时间长短，可以控制导电物质部分沉积在第一子通孔141、第二子通孔142及第三子通孔143的内侧壁上，避免过长的沉积时间导致导电物质堵塞通孔14。
本申请还提供了一种负极22，负极22包括上述任一实施方式中的集流体1。具体的，集流体1请参阅上文描述，在此不再赘述。在本申请中，集流体1可以直接作为负极22使用，负极22无需设置负极活性材料层，此时负极22为无锂负极，采用本申请提供的集流体1作为负极22时可以大大提升负极22的电化学性能和安全性能。
本申请还提供了一种电化学储能装置2，电化学储能装置2包括如上述负极22。请参阅图8，为本申请一实施方式提供的电化学储能装置剖视示意图，电化学储能装置2包括正极21及负极22。在一实施方式中，集流体1作为电化学储能装置2的负极22。
具体的，在本实施方式中，电化学储能装置2为无锂负极-锂电池，即无负极电池，在其他可能的实施方式中，电化学储能装置2还可以是其他类型的电池，本申请对此不加以限制。
在本实施方式中，集流体1的孔隙率β、正极21的面容量C、集流体1在层叠方向上的厚度d和容量-厚度常数k满足公式：
Figure PCTCN2022095943-appb-000002
其中，k＝5×10 -4cm 3/mAh。
需要说明的是，通常情况下电化学储能装置2包括正极21及负极22，集流体1作为电化学储能装置2的负极22。集流体1的孔隙率β是指通孔14的总体积与集流体1的总体积的百分比值，正极21面容量是指电化学储能装置2的正极21每单位表面积可释放的电子总数。通过设置集流体1的孔隙率及集流体1的厚度，可以提高正极21面容量，使得整体的能量密度增大。在一实施例中，β≥50％，C≥5mAh/cm 2。较高的孔隙率可以保证在集流体1厚度相对较低的情况下，还能够满足锂沉积所需的空间，避免了无序的锂沉积导致的体积膨胀，提升了集流体1的安全性能。进一步的，β≥60％，C≥6mAh/cm 2。
在本实施方式中，正极21包括正极集流体和正极活性材料层。在一实施例中，正极活性材料层的材质包括LiFe aMn bM cPO 4、Li 3V 2(PO 4) 3、Li 3V 3(PO 4) 3、LiNi 0.5- dMn 1.5- eN d+ eO 4、LiVPO 4F、Li 1+ fL 1- g- hH gR hO 2、Li 2CuO 2、Li 5FeO 4中的一种或多种；其中，0≤a≤1，0≤b≤1，0≤c≤1，a+b+c＝1，M为Al、Mg、Ga、Ti、Cr、Cu、Zn、Mo中的至少一种；-0.1≤d≤0.5，0≤e≤1.5，N为Li、Co、Fe、Al、Mg、Ca、Ti、Mo、Cr、Cu、Zn中的至少一种；-0.1≤f≤0.2，0≤g≤1，0≤h≤1，0≤g+h≤1.0，L、H和R分别独立选自Li、Co、Mn、Ni、Fe、Al、Mg、Ga、Ti、Cr、 Cu、Zn、Mo、F、I、S、B中的至少一种。在一具体实施例中，正极活性材料层的材质包括LiAl 0.05Co 0.15Ni 0.80O 2、LiNi 0.80Co 0.10Mn 0.10O 2、LiNi 0.90Co 0.05Mn 0.05O 2、LiNi 0.60Co 0.20Mn 0.20O 2、LiCoO 2、LiMn 2O 4、LiFePO 4、LiMnPO 4、LiNiPO 4、LiCoPO 4、LiNi 0.5Mn 1.5O 4和Li 3V 3(PO 4) 3中的至少一种。在另一具体实施例中，正极活性材料层的材质包括硫化锂、嵌锂态V 2O 5、嵌锂态MnO 2、嵌锂态TiS 2和嵌锂态FeS 2中的至少一种。
在本实施方式中，电化学储能装置2还包括设置在正极21和负极22之间的隔膜23。隔膜23用于将电化学储能装置2的正极21及负极22分隔，且本申请对隔膜23的材料不加以限制。
本申请实施方式提供的电化学储能装置2，由于包含了上述的集流体1，集流体使得电化学储能装置2具有能量密度大、充放电容量高，不易产生锂枝晶、安全性能高、循环寿命长点。
接下来，将分多个实施例对本申请实施方式进行进一步的说明。
实施例1
一种集流体的制备方法，包括：
(1)将第一PET膜(厚度18μm)安装在真空磁控溅射镀膜机中，用真空泵抽真空使腔体的真空度到达8×10 -2Pa，再通入一定的氩气进行调节，使真空度达到2×10 -1Pa，对第一PET膜进行表面离子源清洗，清洗时间为5min，清洗完成后，关闭离子源电源；然后启动镀铜电源进行磁控溅射镀金属铜过程，溅射镀金属铜时间为30min，得到厚度为4μm的金属铜箔；
(2)采用熔融挤出压延机(熔融温度设定300℃)在金属铜箔背离第一PET膜的表面压延制备厚度约18μm的第二PET膜；
(3)在第一PET膜和第二PET膜背离金属铜箔的表面均设置透明胶保护膜，得到复合结构；采用超快激光(波长355nm)在复合结构上成型阵列排布的多个通孔，通孔贯穿复合结构在层叠方向上相对两个表面，通孔的孔径为10μm，得到多孔复合结构；
(4)将多孔复合结构转移到热蒸发仪中，待真空泵抽真空使腔体的真空度到达4×10 -1Pa，升温400℃，将金属镁沉积于通孔的内壁表面上，沉积时间10min，降温至100℃后，关闭真空，取出并剥离除去透明胶保护膜即得到集流体Z1，其孔隙率为75％。
实施例2
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于第一PET膜和第二PET膜的厚度为16.75μm，孔隙率和孔径分别为80％和10μm，得到集流体Z2。
实施例3
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于第一PET膜和第二PET膜的厚度为28μm，孔隙率和 孔径分别为50％和5μm，得到集流体Z3。
实施例4
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于步骤(3)后直接去除透明胶保护膜，不进行步骤(4)，得到集流体Z4。
实施例5
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于多个通孔呈无序排布，得到集流体Z5。
实施例6
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于金属铜箔的厚度为8μm，第一PET膜和第二PET膜的厚度为16μm，得到集流体Z6。
实施例7
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于孔隙率和孔径分别为50％和10μm，得到集流体Z7。
实施例8
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于在第一PET膜背离金属铜箔的表面以及第二PET膜背离金属铜箔的表面均设置有多孔聚丙烯蜡阻燃层，得到集流体Z8。
实施例9
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于在第二PET膜中具有镁铝合金颗粒，镁铝合金颗粒的在第二PET膜中的质量占比为1wt％，且第二PET膜的表面绝缘，得到集流体Z9。
实施例10
一种集流体的制备方法，包括：
与实施例1大致相同，不同之处在于孔隙率和孔径分别为80％和10μm，得到集流体Z10。
对比例1
与实施例1大致相同，不同之处在于步骤(4)中先剥离去除表面的透明胶保护膜，再进行同样的蒸镀过程，得到集流体DZ1。
对比例2
与实施例1大致相同，不同之处在于步骤(3)中的每次激光造孔的处理时间缩小一半，得到非通孔的阵列多孔结构，孔径10μm，由于非通孔，孔隙率为67.5％，得到集流体DZ2。
为了说明本申请实施方式提供的集流体的电化学性能，现进行以下测试步骤：
(1)全电池的制备和电化学循环测试：
①采用真空搅拌机将正极活性材料(LiFePO 4)49g、导电剂(乙炔黑)0.5g和粘结剂(聚偏氟乙烯、PVDF)0.5g在NMP中混合均匀以形成稳定均一浆料，其中，搅拌的速度为1000rpm，时间为12h；然后将得到的浆料涂覆在集流体铝片上，控制面密度为220g/m 2，然后在80℃下烘干，再裁剪成61×72mm尺寸的正极片；然后80℃烘干，经过辊压机压片后得到正极片，取其中一片裁成直径13mm片组装扣式电池进行容量标定，标定容量为6mAh/cm 2。
②上述实施例以及对比例得到的集流体Z或DZ直接作为负极，并分别与隔膜和正极片逐层叠加组装成电池，并滴加2.2mL/Ah电解液，电解液为1wt％的LiNO 3溶于4MLiFSI的乙二醇二甲醚(DME)，随后进行封装即分别得到电池S1-S10和DS1-DS2。
电池S1-S10和DS1-DS2各取5支，在二次电池性能检测装置上，分别在25℃条件下，将电池以0.2C进行充放电循环测试。步骤如下：搁置10min；0.2C恒流充电至3.8V，恒压充电至3.8V/0.05C截止；搁置10min；以0.5C放电至2.7V，即为1次循环。重复该步骤，循环过程中当电池容量低于首次放电容量的80％时，循环终止，该循环次数即为电池的循环寿命，每组取平均值，该参数与电池平均首次放电容量的数据，以及电池循环前后的厚度变化率如表1所示。
表1电池平均首次放电容量的数据及电池循环前后的厚度变化率表
Figure PCTCN2022095943-appb-000003
Figure PCTCN2022095943-appb-000004
(2)阻抗(EIS)测试：另取电池S1-S10和DS1-DS2各2支注液后静置，分别每隔0.5h进行阻抗测试(振幅5mV，频率1000-0.01Hz)，实验结果如表2所示。
表2电池阻抗变化表(Ω)
Figure PCTCN2022095943-appb-000005
Figure PCTCN2022095943-appb-000006
(3)能量密度：根据表1中的实验结果进行能量密度评估，实验结果如表3所示。
其中，质量能量密度＝(首次放电容量*首次放电平均电压)/电池质量；
体积能量密度＝(第n次放电容量*第n次放电平均电压)/电池体积；
上述电池质量为不包含壳体、盖板和设置在壳体、盖板上的零部件的电芯质量；上述电池体积为不包含不包含壳体、盖板和设置在壳体、盖板上的零部件的电芯体积。
表3电池能量密度评估表
Figure PCTCN2022095943-appb-000007
Figure PCTCN2022095943-appb-000008
(4)金属锂的沉积实验：另取电池S1-S10和DS1-DS2各2支进行首次锂沉积。在25℃下，以0.6mA/cm 2的电流密度下充电至3.8V，拆电池观察锂的沉积位置，实验结果如表4所示。
表4电池锂沉积位置表
Figure PCTCN2022095943-appb-000009
Figure PCTCN2022095943-appb-000010
可以理解的，从以上表格数据中可以得出，对比例虽然在初期具有与实施例基本相当的质量能量密度和体积能量密度，但是对比例中锂金属易于沉积在负极表面，循环后容量衰减快，电池体积膨胀大，体积能量密度在循环后期最低，本申请实施例提供的电池包含了本申请提供的集流体，使得电池具有能量密度大、充放电容量高，不易产生锂枝晶、安全性能高、循环寿命长。
本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施方式的说明只是用于帮助理解本申请的核心思想；同时，对于本领域的一般技术人员，依据本申请的思想，在具体实施方式及应用范围上均会有改变之处，综上，本说明书内容不应理解为对本申请的限制。

Claims (20)

  1. 一种集流体，包括：
    第一聚合物层；
    金属层，所述金属层位于所述第一聚合物层的一侧；
    第二聚合物层，所述第二聚合物层位于所述金属层远离所述第一聚合物层的一侧，
    自所述第一聚合物层指向所述第二聚合物层的方向上，所述集流体具有贯穿所述集流体的多个通孔。
  2. 根据权利要求1所述的集流体，进一步包括：
    导电层，所述导电层设置在所述通孔的内侧壁上。
  3. 根据权利要求1或2所述的集流体，多个所述通孔呈阵列形式分布。
  4. 根据权利要求3所述的集流体，所述通孔的孔径小于或等于10μm。
  5. 根据权利要求1-4任一项所述的集流体，所述集流体还包括含锂金属层，所述含锂金属层位于所述金属层内。
  6. 根据权利要求5所述的集流体，所述含锂金属层的厚度为10nm-2μm。
  7. 根据权利要求1-6任一项所述的集流体，所述集流体还包括阻燃层，所述阻燃层设置于以下位置的至少之一处：
    所述第一聚合物层背离所述金属层的一侧，和
    所述第二聚合物层背离所述金属层的一侧。
  8. 根据权利要求7所述的集流体，所述阻燃层的厚度为10nm-1μm。
  9. 根据权利要求1-8任一项所述的集流体，所述集流体进一步具有补锂材料，所述补锂材料位于以下位置的至少之一处：
    所述第一聚合物层中；以及
    所述第二聚合物层中。
  10. 根据权利要求9所述的集流体，所述补锂材料满足以下条件的至少之一：
    所述补锂材料在所述第一聚合物层中的质量占比为0.1wt％-5wt％；
    所述补锂材料在所述第二聚合物层中的质量占比为0.1wt％-5wt％；
    所述补锂材料包括Li-Mg、Li-Al、Li-Si、Li-Ag、Li-Au、Li-Sn、Li-In和Li-Ge合金中的至少一种。
  11. 根据权利要求9或10所述的集流体，所述集流体满足以下条件的至少之一：
    所述第一聚合物层背离所述金属层的一侧的电子电导率，低于所述第一聚合物层朝向所述金属层一侧的电子电导率；和
    所述第二聚合物层背离所述金属层的一侧的电子电导率，低于所述第二聚合物层朝向 所述金属层一侧的电子电导率。
  12. 根据权利要求9-11任一项所述的集流体，所述集流体满足以下条件的至少之一：
    所述第一聚合物层背离所述金属层的一侧绝缘，和
    所述第二聚合物层背离所述金属层的一侧绝缘。
  13. 根据权利要求1-12任一项所述的集流体，所述集流体满足以下条件的至少之一：
    所述金属层的厚度小于或等于4μm；
    所述第一聚合物层的厚度为11μm-26μm；
    所述第二聚合物层的厚度为11μm-26μm。
  14. 根据权利要求1-13任一项所述的集流体，形成所述金属层的材质包括铜、金、银、镁、锌、钛、镍中的至少一种或不锈钢。
  15. 根据权利要求1-14任一项所述的集流体，所述通孔的孔径形状包括圆柱形、长方管形、立方管形、梯形圆柱形、三角锥形中的至少一种。
  16. 根据权利要求15所述的集流体，所述通孔沿所述第一或第二聚合物层所在平面的截面满足以下条件的至少之一：
    所述截面自所述金属层指向所述第一聚合物层的方向上逐渐增大；
    所述截面自所述金属层指向所述第二聚合物层的方向上逐渐增大。
  17. 一种制备集流体的方法，所述方法包括：
    将第一聚合物膜、金属膜和第二聚合物膜依次层叠设置，形成第一复合结构；
    将第一保护膜设置于所述第一聚合膜层背离所述金属膜的一侧表面，将第二保护膜设置于所述第二聚合物膜背离所述金属膜的一侧表面，形成第二复合结构；
    在所述第二复合结构上形成多个通孔，所述通孔贯穿所述第二复合结构在所述层叠方向上的相对两个表面；
    去除所述第一保护膜和所述第二保护膜，以得到所述集流体。
  18. 一种负极，所述负极包括权利要求1-16任一项所述的或权利要求17所述的方法制得的集流体。
  19. 一种电化学储能装置，所述电化学储能装置包括正极和权利要求18所述的负极。
  20. 根据权利要求19所述的电化学储能装置，所述集流体的孔隙率β、所述正极的面容量C、所述集流体在层叠方向上的厚度d和容量-厚度常数k满足公式：
    Figure PCTCN2022095943-appb-100001
    所述β≥50％，所述C≥5mAh/cm 2，所述k＝5×10 -4cm 3/mAh。
PCT/CN2022/095943 2021-06-01 2022-05-30 集流体及制备的方法、负极和电化学储能装置 Ceased WO2022253174A1 (zh)

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