Current collector and method for manufacturing current collector

Abstract

Disclosed in embodiments of the present application are a current collector and a method for manufacturing a current collector. The method comprises: metallizing a surface of a release substrate to form a conductive layer to obtain a first structure; providing an adhesive layer on a surface of a polymer substrate layer; attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer to obtain a second structure; and peeling off the release substrate of the second structure to obtain a current collector. The current collector and the method for manufacturing a current collector disclosed in the embodiments of the present application can improve the processing efficiency of current collectors and the reliability of the current collectors.

Description

Current collector and methods for preparing current collectors Cross-references to related applications

[0001] This application claims priority to Chinese Patent Application No. 202510005570.8, filed on January 2, 2025, entitled “Current collector and method for preparing current collector”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and more specifically, to a current collector and a method for preparing the current collector. Background Technology

[0003] In a battery cell, the current collector, serving as a carrier for the positive and negative electrode active material layers, also plays a crucial role in electron transport, making it a vital component of the cell. The density and thickness of the current collector directly affect the battery's energy density. Due to the inherent low flexibility of metals, reducing the thickness beyond a certain point significantly increases processing difficulty and reduces yield. Therefore, composite current collectors with polymer substrates as support have become the main direction for reducing the thickness and density of future current collectors.

[0004] However, there are many challenges in the current processing of composite current collectors, and how to improve the processing efficiency of current collectors is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a current collector and a method for preparing the current collector, which can improve the processing efficiency and reliability of the current collector.

[0006] In a first aspect, a method for preparing a current collector is provided, comprising: metallizing a conductive layer on the surface of a release substrate to obtain a first structure; providing an adhesive layer on the surface of a polymer substrate layer; attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer to obtain a second structure; and peeling off the release substrate of the second structure to obtain the current collector.

[0007] Therefore, compared with the method of directly metallizing on a polymer substrate to obtain a composite current collector, the method of this application embodiment can improve the processing efficiency of the current collector, effectively improve the reliability of the current collector, and reduce the risk of the conductive layer falling off.

[0008] In some embodiments, attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: subjecting the surface of the adhesive layer away from the polymer substrate layer to corona treatment and / or plasma treatment, and then attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer, so as to improve the bonding reliability between the conductive layer and the adhesive layer and thereby reduce the risk of the conductive layer falling off.

[0009] In some embodiments, after the corona treatment and / or plasma treatment are performed on the surface of the adhesive layer away from the polymer substrate layer, the dyne value of the surface of the adhesive layer away from the polymer substrate layer is in the range of [38, 60], so as to maintain the adhesive ability of the adhesive layer surface, thereby improving the bonding reliability between the conductive layer and the adhesive layer, and thus reducing the risk of the conductive layer falling off; at the same time, the dyne value of the adhesive layer surface should not be too large, so as to reduce the difficulty of material selection and processing.

[0010] In some embodiments, attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: performing a passivation treatment on the surface of the conductive layer away from the release substrate; attaching the passivated surface of the conductive layer to the surface of the adhesive layer away from the polymer substrate layer, so that the conductive layer is not easily corroded, thereby improving the structural reliability and service life of the current collector.

[0011] In some embodiments, the material of the passivated surface of the conductive layer includes metal oxides and / or chromates to facilitate processing.

[0012] In some embodiments, the thickness of the passivation layer after passivation treatment ranges from [10nm, 100nm]. Setting the passivation layer to be relatively thick, for example, greater than or equal to 10nm, can improve the corrosion resistance of the passivation layer; however, the thickness of the passivation layer should not be too large, for example, the thickness is usually less than or equal to 100nm, on the one hand, reducing the impact of the passivation layer on the conductivity of the conductive layer, and on the other hand, reducing the volume of the passivation layer, thereby reducing the volume of the current collector and increasing the energy density of the battery cell using the current collector.

[0013] In some embodiments, attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer by single-roller hot pressing or double-roller hot pressing, which is simple to operate and easy to implement.

[0014] In some embodiments, when the conductive layer of the first structure is bonded to the surface of the adhesive layer away from the polymer substrate layer: the bonding temperature ranges from [70°C to 200°C], and / or the bonding speed ranges from [0.5 m / min to 100 m / min].

[0015] Setting a higher bonding temperature, such as above or equal to 70°C, can improve the bonding effect and enhance the stability between the adhesive layer and the conductive layer. However, the bonding temperature should not be too high, such as usually not exceeding 200°C, in order to reduce structural deformation, such as reducing the deformation of the polymer substrate layer and improving the reliability of the structure.

[0016] Setting a relatively fast bonding speed, such as typically greater than or equal to 0.5 m / min, can increase processing speed and thus improve the processing efficiency of the current collector; however, the bonding speed should not be too fast, such as typically less than or equal to 100 m / min, to prevent insufficient bonding time between the adhesive layer and the conductive layer from affecting their adhesion and stability, thereby reducing the risk of the conductive layer falling off.

[0017] In some embodiments, the peeling angle when peeling the release substrate of the second structure ranges from [30°, 180°]. Setting a larger peeling angle, such as greater than or equal to 30°, facilitates the peeling of the conductive layer from the release substrate and the recovery of the release substrate, thereby improving peeling efficiency; however, the peeling angle generally cannot exceed 180° to facilitate the recovery of the release substrate.

[0018] In some embodiments, the surface energy of the release substrate ranges from (0, 35). Limiting the surface energy of the release substrate to no more than 35 facilitates the peeling of the conductive layer from the release substrate, thereby improving processing efficiency.

[0019] In some embodiments, peeling off the release substrate of the second structure to obtain the current collector includes: after peeling off the release substrate of the second structure, curing the second structure after peeling off the release substrate to obtain the current collector. This method can improve the structural stability and reliability of the current collector.

[0020] In some embodiments, the curing of the second structure from which the release substrate has been removed includes: curing the second structure from which the release substrate has been removed by static curing and / or hot rolling curing. The above curing method is simple and easy to implement.

[0021] In some embodiments, the curing temperature range for curing the second structure after the release substrate has been peeled off is [60°C, 150°C]. Setting a higher curing temperature, such as above or equal to 60°C, can improve the structural stability of the processed current collector; however, the curing temperature should not be too high, for example, it usually does not exceed 150°C, in order to reduce structural deformation, such as reducing the amount of deformation of the polymer substrate layer, and improving the reliability of the structure.

[0022] In some embodiments, the method of providing an adhesive layer on the surface of the polymer substrate layer includes: providing the adhesive layer on two opposing surfaces of the polymer substrate layer; attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer to obtain the second structure includes: attaching the conductive layers of the two first structures to the surfaces of the adhesive layers located on the two surfaces of the polymer substrate layer away from the polymer substrate layer to obtain the second structure; and peeling off the release substrate of the second structure to obtain the current collector includes: peeling off the two release substrates of the second structure to obtain the current collector. This method can improve the processing efficiency and structural stability of the current collector.

[0023] In some embodiments, the material of the release substrate includes at least one of the following: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide, polybutylene terephthalate, other polyolefin resins, copper foil, aluminum foil, iron foil and stainless steel foil, which are readily available and easy to process.

[0024] In some embodiments, the thickness of the release substrate is in the range of [20μm, 60μm]. Setting the thickness of the release substrate appropriately can improve the processing efficiency and reliability of the current collector.

[0025] In a second aspect, a current collector is provided, comprising: a conductive layer; an adhesive layer; and a polymer substrate layer, wherein the adhesive layer is located between the conductive layer and the polymer substrate layer.

[0026] In some embodiments, the current collector includes two conductive layers and two adhesive layers. The two adhesive layers are respectively located on two opposing surfaces of the polymer substrate layer, and the two conductive layers are respectively located on the surfaces of the adhesive layers on the two surfaces of the polymer substrate layer that are away from the polymer substrate layer. The current collector has a stable structure and good performance.

[0027] In some embodiments, the current collector is a current collector prepared by the method described in the first aspect or any embodiment of the first aspect.

[0028] In some embodiments, the materials of the conductive layer, the adhesive layer, and the polymer substrate layer satisfy at least one of the following conditions: the conductive layer material includes at least one of the following: copper, aluminum, titanium, cobalt, and nickel; the adhesive layer material includes at least one of the following: acrylate, polyurethane, polyester polyol, maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, acrylic-modified polypropylene, acrylic-modified polyethylene, modified polyolefin resin, epoxy resin, ternary copolymer polyolefin, multi-component copolymer polyolefin resin, and polyamide; the polymer substrate layer material includes at least one of the following: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide, and polybutylene terephthalate. These materials are readily available and easy to process.

[0029] In some embodiments, the thicknesses of the conductive layer, the adhesive layer, the polymer substrate layer, and the current collector satisfy at least one of the following conditions: the thickness of the conductive layer ranges from [500 nm to 2000 nm]; the thickness of the adhesive layer ranges from [0.4 μm to 1.4 μm]; the thickness of the polymer substrate layer ranges from [3 μm to 14 μm]; and the thickness of the current collector ranges from [3 μm to 15 μm]. By rationally setting the thickness of each layer, the structure meets design requirements, thereby improving the processing efficiency and reliability of the current collector. Attached Figure Description

[0030] Figure 1 is a schematic flowchart of a method for preparing a current collector according to an embodiment of this application;

[0031] Figure 2 is an exploded structural diagram of a battery cell according to an embodiment of this application;

[0032] Figure 3 is a schematic diagram of a first structure according to an embodiment of this application;

[0033] Figure 4 is a schematic diagram of a polymer substrate layer with an adhesive layer provided in an embodiment of this application;

[0034] Figure 5 is a schematic diagram of a second structure according to an embodiment of this application;

[0035] Figure 6 is a schematic diagram of a passivated first structure according to an embodiment of this application;

[0036] Figure 7 is a schematic diagram of a current collector according to an embodiment of this application;

[0037] Figure 8 is a schematic diagram of a partial structure of a device for preparing a current collector according to an embodiment of this application.

[0038] The accompanying drawings are not drawn to scale.

[0039] Reference numerals: 20-cell battery; 21-casing; 211-shell; 212-cover plate; 214-electrode terminal; 214a-positive electrode terminal; 214b-negative electrode terminal; 22-electrode assembly; 221-main body; 222-tab; 222a-positive tab; 222b-negative tab; 23-current collector; 30-current collector; 301-first structure; 302-second structure; 31-release substrate; 32-conductive layer; 321-passivation layer; 33-polymer substrate layer; 34-adhesive layer; 341-first adhesive layer; 342-second adhesive layer; 41-roller. Detailed Implementation

[0040] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0043] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0047] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0048] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0049] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0050] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0051] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0052] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0053] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0054] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0055] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0056] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0057] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 At least one of the following: lithium nickel cobalt aluminum oxides (such as LiNi0.8Co0.15Al0.05O2) and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned substances.

[0058] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, a positive electrode active material is filled and / or deposited within the foamed metal.

[0059] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0060] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0061] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0062] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0063] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0064] In some embodiments, the negative electrode can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not contain a negative electrode active material.

[0065] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0066] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0067] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0068] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0069] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0070] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0071] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0072] Liquid electrolytes include electrolyte salts and solvents.

[0073] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0074] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0075] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0076] The gel electrolyte includes a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0077] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0078] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0079] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium-germanium-phosphorus-sulfur, sulfosilium-germanium), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0080] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0081] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0082] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0083] In some implementations, the electrode assembly is a stacked structure.

[0084] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0085] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0086] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0087] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0088] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0089] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0090] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0091] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0092] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0093] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0094] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0095] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0096] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0097] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0098] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0099] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0100] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0101] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0102] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0103] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0104] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0105] In a battery cell, the current collector, serving as a carrier for the positive and negative electrode active material layers, also plays a crucial role in electron transport, making it a vital component of the cell. The density and thickness of the current collector directly affect the battery's energy density. Due to the inherent low flexibility of metals, reducing the thickness beyond a certain point significantly increases processing difficulty and reduces yield. Therefore, composite current collectors with polymer substrates as support have become the main direction for reducing the thickness and density of future current collectors.

[0106] However, the current processing of composite current collectors faces numerous challenges: 1. The process of forming a conductive layer using an extremely thin polymer substrate layer through one or more steps such as vapor deposition, magnetron sputtering, electroplating, and electroless plating involves more than a dozen processes, leading to difficulties in process control and low yield; 2. Insufficient adhesion between the polymer substrate layer and the metal conductive layer poses a risk of detachment during practical applications. Therefore, improving the processing efficiency of current collectors is an urgent problem to be solved.

[0107] This application provides a current collector and a method for preparing the current collector. This solves the problems mentioned above.

[0108] Figure 1 shows a schematic flowchart of a method 100 for preparing a current collector 30 according to an embodiment of this application. As shown in Figure 1, the method 100 of this embodiment includes: S110, forming a conductive layer 32 by metallization on the surface of a release substrate 31 to obtain a first structure 301; S120, providing an adhesive layer 34 on the surface of a polymer substrate layer 33; S130, attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33 to obtain a second structure 302; S140, peeling off the release substrate 31 of the second structure 302 to obtain the current collector 30.

[0109] It should be understood that the method 100 in the embodiments of this application can be used to prepare the current collector 30, which can be the positive current collector of the positive electrode or the negative current collector of the negative electrode. That is, the method 100 can be used to prepare the positive current collector or the negative current collector. The embodiments of this application are not limited thereto.

[0110] Method 100 of this application embodiment involves providing an adhesive layer 34 on the surface of a polymer substrate layer 33, bonding the conductive layer 32 of a first structure 301 to the adhesive layer 34 to obtain a second structure 302, and then peeling off the release substrate 31 of the second structure 302 to obtain a current collector 30. Compared with the method of directly metallizing on the polymer substrate to obtain a composite current collector, this method 100 can improve the processing efficiency of the current collector 30 and effectively improve the reliability of the current collector 30, reducing the risk of the conductive layer 32 detaching. For example, in the case of direct metallization on the polymer substrate, if the polymer substrate is very thin, the metallization speed will be very slow due to process limitations, usually less than 20 m / min, while the speed of method 100 of this application can reach 50 m / min, greatly improving the processing efficiency. Conversely, in the case of direct metallization on a polymer substrate, if the polymer substrate is very thick, the overall structure of the composite current collector will be thickened, which will affect the energy density of the battery cell using the composite current collector. However, the current collector 30 prepared by the method 100 of this application embodiment can meet the design requirements of the energy density of the battery cell 20.

[0111] It should be understood that the current collector 30 in this embodiment can be used in the electrode assembly 22. Figure 2 shows an exploded structural diagram of the battery cell 20 in this embodiment. As shown in Figure 2, the battery cell may include one or more electrode assemblies 22 and a housing 21 for accommodating the electrode assembly 22.

[0112] It should be understood that, as shown in FIG2, the outer casing 21 of this embodiment can be a polyhedral structure. Specifically, the outer casing 21 may include a housing 211 and a cover plate 212. The housing 211 may be a hollow structure with an opening at at least one end, and the shape of the cover plate 212 may be adapted to the shape of the housing 211. The cover plate 212 is used to cover the opening of the housing 211 so that the housing 21 isolates the internal environment of the battery cell 20 from the external environment. For example, if the housing 211 is a hollow structure with an opening at one end, the cover plate 212 may be set as one, as shown in FIG2. In contrast, if the housing 211 has multiple openings, for example, if the housing 211 is a hollow structure with openings at opposite ends, the cover plate 212 may be set as two, and the two cover plates 212 respectively cover the openings at both ends of the housing 211.

[0113] The shell 211 in this embodiment can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The cover plate 212 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 can be the same as or different from that of the shell 211.

[0114] The outer shell 21 of this application embodiment can be of various shapes, such as a cylinder, a cuboid, etc. The shapes of the shell 211 and the cover plate 212 are mutually compatible. For example, as shown in FIG2, the shell 211 can be a cuboid structure, and the cover plate 212 is a rectangular plate structure adapted to the shell 211.

[0115] For ease of explanation, this application uses a cuboid shell 21 as an example. Specifically, as shown in Figure 2, the shell 21 includes: a housing 211, which is a hollow structure with one end open; and a cover plate 212, which is used to cover the opening of the housing 211 to form a closed cavity for placing the electrode assembly 22.

[0116] In this battery cell 20, the housing 211 is used to house the electrode assembly 22, and the electrode assembly 22 inside the housing 211 can be configured as one or more depending on the actual usage requirements. For example, FIG2 shows a battery cell 20 including four electrode assemblies 22 disposed along the thickness direction of the battery cell 20, but the embodiments of this application are not limited to this.

[0117] The electrode assembly 22 in this embodiment is a component in the battery cell 20 where an electrochemical reaction occurs. The electrode assembly 22 can be a cylinder, a cuboid, etc. If the electrode assembly 22 is a cylindrical structure, the housing 211 can also be a cylindrical structure; if the electrode assembly 22 is a cuboid structure, the housing 211 can also be a cuboid structure.

[0118] For any electrode assembly 22, the electrode assembly 22 may include tabs 222 and a main body 221. Specifically, as shown in FIG2, the electrode assembly 22 may include at least two tabs 222, which may include a positive tab 222a and a negative tab 222b. The positive tab 222a may be formed by stacking the portion of the positive electrode sheet that is not coated with the positive active material, and the negative tab 222b may be formed by stacking the portion of the negative electrode sheet that is not coated with the negative active material; the electrode main body 221 may be formed by stacking or winding the positive and negative electrode sheets together.

[0119] The outer casing 21 of this embodiment is further provided with electrode terminals 214, which are used to electrically connect with the electrode assembly 22 to output the electrical energy of the battery cell 20. Specifically, the battery cell 20 may also include at least two electrode terminals 214, which can be disposed on any wall of the battery cell 20, and can be located on the same wall or different walls. For example, as shown in FIG2, the cover plate 212 is usually flat, and at least two electrode terminals 214 of the battery cell 20 can be fixed on the flat surface of the cover plate 212.

[0120] The battery cell 20 has at least two electrode terminals 214, including at least one positive electrode terminal 214a and at least one negative electrode terminal 214b. The positive electrode terminal 214a is used for electrical connection to the positive electrode tab 222a of the electrode assembly 22, and the negative electrode terminal 214b is used for electrical connection to the negative electrode tab 222b of the electrode assembly 22. The positive electrode terminal 214a and the positive electrode tab 222a can be directly or indirectly connected, and the negative electrode terminal 214b and the negative electrode tab 222b can also be directly or indirectly connected. For example, as shown in FIG2, the positive electrode terminal 214a can be electrically connected to the positive electrode tab 222a through a current collector 23, and the negative electrode terminal 214b can be electrically connected to the negative electrode tab 222b through a current collector.

[0121] The method 100 of the present application embodiment will now be described with reference to the accompanying drawings.

[0122] It should be understood that S110 of method 100 in this application embodiment includes: forming a conductive layer 32 by metallizing on the surface of a release substrate 31 to obtain a first structure 301, the first structure 301 including the release substrate 31 and the conductive layer 32. For example, FIG3 shows a schematic diagram of the first structure 301 in an embodiment of this application.

[0123] In some embodiments, the metallization method in S110 can be set according to the actual application. For example, S110 may specifically include: forming a conductive layer 32 on the surface of the release substrate 31 by at least one of the following methods: vacuum evaporation, magnetron sputtering, and electroplating. These methods are simple and easy to implement.

[0124] It should be understood that the material of the release substrate 31 in the embodiments of this application can also be set according to the actual application. For example, the material of the release substrate 31 includes at least one of the following: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide, polybutylene terephthalate, other polyolefin resins, copper foil, aluminum foil, iron foil, stainless steel foil and other alloy foil, to facilitate implementation.

[0125] It should be understood that the dimensions of the release substrate 31 in this embodiment can also be set according to actual application. For example, as shown in Figure 3, the thickness T1 of the release substrate 31 ranges from [20μm to 60μm]. Setting the thickness T1 of the release substrate 31 to be larger, such as greater than or equal to 20μm, can improve the structural stability of the release substrate 31; however, the thickness T1 of the release substrate 31 should not be too large, for example, the thickness T1 is usually less than or equal to 60μm, so as to facilitate the subsequent peeling of the release substrate 31 from the conductive layer 32.

[0126] It should be understood that the material of the conductive layer 32 in the embodiments of this application can also be set according to the actual application. For example, the material of the conductive layer 32 includes at least one of the following: copper, aluminum, titanium, cobalt and nickel, so as to meet the needs of the battery cell 20, and select a suitable conductive layer 32 to process to obtain a positive electrode current collector or a negative electrode current collector.

[0127] It should be understood that the size of the conductive layer 32 in this embodiment can also be set according to the actual application. For example, as shown in Figure 3, the value range of is [500nm, 2000nm]. Setting the thickness T2 of the conductive layer 32 to be relatively large, for example, greater than or equal to 500nm, can improve the structural stability of the conductive layer 32; however, the thickness T2 of the conductive layer 32 should not be too large, for example, the thickness T2 is usually less than or equal to 2000nm, so as to reduce the volume of the conductive layer 32, thereby reducing the volume of the current collector 30 and improving the energy density of the battery cell 20 using the current collector 30.

[0128] It should be understood that S120 of method 100 in this application embodiment includes: providing an adhesive layer 34 on the surface of the polymer substrate layer 33. For example, FIG4 shows a schematic diagram of the polymer substrate layer 33 with adhesive layer 34 provided in this application embodiment. In some embodiments, considering that the current collector 30 can generally be configured as a symmetrical structure, as shown in FIG4, S120 may specifically include: providing adhesive layers 34 on two oppositely disposed surfaces of the polymer substrate layer 33. For example, a first adhesive layer 341 and a second adhesive layer 342 may be provided on two oppositely disposed surfaces of the polymer substrate layer 33. The adhesive layer 34 in this application embodiment includes the first adhesive layer 341 and the second adhesive layer 342 to facilitate subsequent processing.

[0129] In some embodiments, the adhesive layers 34 on both sides of the polymer substrate layer 33 can be processed simultaneously, that is, the adhesive layers 34 are simultaneously provided on both surfaces of the polymer substrate layer 33 to improve processing efficiency; or, the adhesive layers 34 on both sides of the polymer substrate layer 33 can be processed separately, for example, the first adhesive layer 34 is first provided on one surface of the polymer substrate layer 33, and then the second adhesive layer 34 is provided on the other surface. The embodiments of this application are not limited to this.

[0130] It should be understood that the method of setting the adhesive layer 34 in the embodiments of this application can be selected according to the actual application. In some embodiments, S120 may specifically include: setting the adhesive layer 34 on the surface of the polymer substrate layer 33 by at least one of the following methods: microgravure coating, hot melt coating, screw extrusion, casting molding and coating molding. These methods are relatively simple to operate and the adhesive layer 34 obtained by processing has high reliability.

[0131] It should be understood that the material of the polymer substrate layer 33 in this application embodiment can be set according to actual application. For example, the material of the polymer substrate layer 33 includes at least one of the following: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide and polybutylene terephthalate, to facilitate implementation.

[0132] It should be understood that the dimensions of the polymer substrate layer 33 in this embodiment can be set according to actual applications. For example, the thickness T3 of the polymer substrate layer 33 can range from [3μm, 14μm]. Setting the thickness T3 of the polymer substrate layer 33 to be relatively large, for example, greater than or equal to 3μm, can improve the structural stability of the polymer substrate layer 33 and thus enhance its supporting effect; however, the thickness T3 of the polymer substrate layer 33 should not be too large, for example, the thickness T3 is usually less than or equal to 14μm, in order to reduce the volume of the polymer substrate layer 33, thereby reducing the volume of the current collector 30 and increasing the energy density of the battery cell 20 using the current collector 30.

[0133] It should be understood that the material of the adhesive layer 34 in this application embodiment can be set according to actual application. For example, the material of the adhesive layer 34 includes at least one of the following: acrylate, polyurethane, polyester polyol, maleic anhydride modified polypropylene, maleic anhydride modified polyethylene, acrylic modified polypropylene, acrylic modified polyethylene, modified polyolefin resin, epoxy resin, ternary copolymer polyolefin, multi-component copolymer polyolefin resin and polyamide. These materials have high structural reliability and are easy to implement.

[0134] In some embodiments, the material of the adhesive layer 34 can be selected according to the method in which the adhesive layer 34 is formed on the surface of the polymer substrate layer 33, so as to improve processing efficiency. For example, if the adhesive layer 34 is formed on the surface of the polymer substrate layer 33 by at least one of hot melt coating, screw extrusion, casting molding and coating molding, the material of the adhesive layer 34 is usually selected as maleic anhydride modified polypropylene and / or ternary copolymer polyolefin; if the adhesive layer 34 is formed on the surface of the polymer substrate layer 33 by microgravure coating, the material of the adhesive layer 34 can usually be any one or more of the above-mentioned materials, but the embodiments of this application are not limited thereto.

[0135] It should be understood that the dimensions of the adhesive layer 34 in this embodiment can be set according to actual application. For example, if adhesive layers 34 are provided on both opposite surfaces of the polymer substrate layer 33, the thicknesses of the two adhesive layers 34 can be the same or different. For example, as shown in FIG4, the thicknesses of the first adhesive layer 341 and the second adhesive layer 342 can be the same, both being T4, to facilitate processing and improve the reliability of the current collector 30.

[0136] For example, the thickness T4 of the adhesive layer 34 can range from [0.4μm to 1.4μm]. Setting the thickness T4 of the adhesive layer 34 to be relatively large, for example, greater than or equal to 0.4μm, can improve the bonding reliability of the adhesive layer 34, thereby improving structural stability and reducing the risk of the conductive layer 32 of the current collector 30 falling off during processing; however, the thickness T4 of the adhesive layer 34 should not be too large, for example, the thickness T4 is usually less than or equal to 1.4μm, in order to reduce the volume of the adhesive layer 34, thereby reducing the volume of the current collector 30 and increasing the energy density of the battery cell 20 using the current collector 30.

[0137] It should be understood that S130 of method 100 in this application embodiment includes: attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33 to obtain a second structure 302, wherein the second structure 302 sequentially includes a release substrate 31, a conductive layer 32, an adhesive layer 34, and a polymer substrate layer 33. For example, FIG5 shows a schematic diagram of the second structure 302 in an embodiment of this application.

[0138] In some embodiments, considering that the current collector 30 can typically be configured as a symmetrical structure, as shown in FIG5, S130 may specifically include: attaching the conductive layers 32 of the two first structures 301 to the surfaces of the adhesive layers 34 located on the two surfaces of the polymer substrate layer 33 that are away from the polymer substrate layer 33, respectively, to obtain a second structure 302. For example, the conductive layer 32 of one of the first structures 301 can be attached to the surface of the first adhesive layer 341 that is away from the polymer substrate layer 33, and the conductive layer 32 of the other first structure 301 can be attached to the surface of the second adhesive layer 342 that is away from the polymer substrate layer 33, to obtain the second structure 302. The second structure 302 includes, in sequence, a release substrate 31, a conductive layer 32, a first adhesive layer 341, a polymer substrate layer 33, a second adhesive layer 342, another conductive layer 32, and another release substrate 31.

[0139] In some embodiments, when the two first structures 301 are bonded to the adhesive layers 34 on both sides, the two first structures 301 can be bonded simultaneously, that is, the first structures 301 are bonded to the surfaces of the first adhesive layer 341 and the second adhesive layer 342 simultaneously to improve processing efficiency; or, the two first structures 301 can be bonded to the adhesive layers 34 on both sides separately, for example, one of the first structures 301 can be bonded to the first adhesive layer 341 first, and then the other first structure 301 can be bonded to the second adhesive layer 342. The embodiments of this application are not limited to this.

[0140] For ease of description, the following description will use the example of attaching any first structure 301 to any adhesive layer 34.

[0141] In some embodiments, S130 may specifically include: after performing corona treatment and / or plasma treatment on the surface of the adhesive layer 34 away from the polymer substrate layer 33, attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33, so as to improve the bonding reliability between the conductive layer 32 and the adhesive layer 34, thereby reducing the risk of the conductive layer 32 falling off.

[0142] In some embodiments, after corona treatment and / or plasma treatment of the surface of the adhesive layer 34 away from the polymer substrate layer 33, the dyne value of the surface of the adhesive layer 34 away from the polymer substrate layer 33 is in the range of [38, 60], so as to maintain the adhesion ability of the surface of the adhesive layer 34, thereby improving the adhesion reliability between the conductive layer 32 and the adhesive layer 34, and thus reducing the risk of the conductive layer 32 falling off; at the same time, limiting the dyne value of the surface of the adhesive layer 34 to less than or equal to 60 can reduce the difficulty of material selection and processing.

[0143] In some embodiments, the dyne value of the surface of the adhesive layer 34 away from the polymer substrate layer 33 can also be other values. For example, the range of the dyne value of the surface of the adhesive layer 34 away from the polymer substrate layer 33 can also be [40, 50], which can improve the bonding reliability between the conductive layer 32 and the adhesive layer 34 and reduce the processing difficulty.

[0144] In some embodiments, S130 may further include: passivating the surface of the conductive layer 32 away from the release substrate 31; and attaching the passivated surface of the conductive layer 32 to the surface of the adhesive layer 34 away from the polymer substrate layer 33. FIG6 shows a schematic diagram of the passivated first structure 301 according to an embodiment of the present application. As shown in FIG6, the conductive layer 32 is disposed on the surface of the release substrate 31. Before attaching it to the adhesive layer 34, the surface of the conductive layer 32 away from the release substrate 31 may be passivated to generate a passivation layer 321, making the conductive layer 32 less susceptible to corrosion and improving the structural reliability and service life of the current collector 30.

[0145] It should be understood that the material of the passivation layer 321 in this embodiment can be set according to the actual application. For example, the material of the passivation layer 321 can be related to the material of the conductive layer 32. As another example, the material of the passivated surface of the conductive layer 32 includes metal oxides and / or chromates, that is, the material of the passivation layer 321 can include metal oxides and / or chromates to facilitate processing.

[0146] It should be understood that the size of the passivation layer 321 in this embodiment can be set according to actual application. For example, after passivation treatment, the thickness T5 of the passivation layer 321 of the conductive layer 32 is in the range of [10nm, 100nm]. Setting the thickness T5 of the passivation layer 321 to be larger, for example greater than or equal to 10nm, can improve the corrosion resistance of the passivation layer 321; however, the thickness T5 of the passivation layer 321 should not be too large, for example, the thickness T5 is usually less than or equal to 100nm. On the one hand, this reduces the influence of the passivation layer 321 on the conductivity of the conductive layer 32, and on the other hand, it can reduce the volume of the passivation layer 321, thereby reducing the volume of the current collector 30 and increasing the energy density of the battery cell 20 using the current collector 30.

[0147] It should be understood that the bonding method used between the conductive layer 32 and the adhesive layer 34 in S130 of method 100 of this application embodiment can be set according to actual application. In some embodiments, S130 may specifically include: bonding the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33 by single-roller hot pressing or double-roller hot pressing, which is simple to operate and easy to implement.

[0148] It should be understood that when bonding the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33, the relevant parameter settings during the bonding process can be determined according to the actual application. For example, the bonding temperature range is [70℃, 200℃]. Setting a higher bonding temperature, such as above or equal to 70℃, can improve the bonding effect and increase the stability between the adhesive layer 34 and the conductive layer 32; however, the bonding temperature should not be too high, for example, it usually will not exceed 200℃, in order to reduce the amount of structural deformation, such as reducing the amount of deformation of the polymer substrate layer 33, and improving the reliability of the structure.

[0149] In some embodiments, the bonding speed ranges from [0.5 m / min to 100 m / min]. Setting the bonding speed to be relatively fast, for example, typically greater than or equal to 0.5 m / min, can increase the processing speed and thus improve the processing efficiency of the current collector 30; however, the bonding speed should not be too fast, for example, typically less than or equal to 100 m / min, to prevent insufficient bonding time between the adhesive layer 34 and the conductive layer 32, which could affect the adhesion and stability between them, thereby reducing the risk of the conductive layer 32 falling off.

[0150] It should be understood that S140 of method 100 in this application embodiment includes: peeling off the release substrate 31 of the second structure 302 to obtain a current collector 30, wherein the current collector 30 sequentially includes: a conductive layer 32, an adhesive layer 34, and a polymer substrate layer 33. For example, FIG7 shows a schematic diagram of the current collector 30 in an embodiment of this application.

[0151] In some embodiments, considering that the current collector 30 can generally be configured as a symmetrical structure, as shown in FIG. 7, when the second structure 302 includes two first structures 301, S140 may specifically include: peeling off the two release substrates 31 of the second structure 302 to obtain the current collector 30. For example, the upper and lower release substrates 31 can be peeled off simultaneously to improve processing efficiency; or, one release substrate 31 can be peeled off first, and then the other release substrate 31 can be peeled off to obtain the current collector 30. The embodiments of this application are not limited to this. As shown in FIG. 7, the current collector 30 after peeling includes, in sequence: a conductive layer 32, a first adhesive layer 341, a polymer substrate layer 33, a second adhesive layer 342, and another conductive layer 32.

[0152] It should be understood that steps S130 and S140 in method 100 can be performed simultaneously to improve processing efficiency; or they can be performed separately, that is, the first structure 301 is first bonded to the adhesive layer 34, and after all bonding is completed, the release substrate 31 is peeled off.

[0153] Figure 8 shows a schematic diagram of a partial structure of the apparatus for preparing the current collector 30 according to an embodiment of this application. As shown in Figure 8, steps S130 and S140 in method 100 of this embodiment can be executed synchronously. Specifically, taking an example where adhesive layers 34 are provided on both opposite surfaces of the polymer substrate layer 33, two first structures 301 are respectively disposed on both sides of the polymer substrate layer 33. Each conductive layer 32 is bonded to the corresponding adhesive layer 34 by rollers 41, here taking a double-roller hot pressing method as an example; the area where the bonding is completed is the second structure 302, and then the release substrates 31 on both sides are peeled off and recycled to obtain the current collector 30.

[0154] Alternatively, unlike Figure 8, two first structures 301 can be first disposed on both sides of the polymer substrate layer 33 to complete the bonding between each conductive layer 32 and the corresponding adhesive layer 34, thereby obtaining the second structure 302. Then, the release substrate 31 on both sides of the second structure 302 is peeled off and recycled to obtain the current collector 30.

[0155] For ease of explanation, the peeling method shown in Figure 8 will be used as an example in the following description.

[0156] It should be understood that the specific parameters involved in the stripping process in S140 can be set according to the actual application.

[0157] In some embodiments, the peeling angle θ when peeling the release substrate 31 of the second structure 302 ranges from [30°, 180°]. Setting the peeling angle θ to be relatively large, for example greater than or equal to 30°, facilitates the peeling of the conductive layer 32 from the release substrate 31 and the recovery of the release substrate 31, thereby improving peeling efficiency; however, the peeling angle θ generally cannot exceed 180° in order to facilitate the recovery of the release substrate.

[0158] In some embodiments, the surface energy of the release substrate 31 ranges from (0, 35). Limiting the surface energy of the release substrate 31 to no more than 35 facilitates the peeling of the conductive layer 32 from the release substrate 31, thereby improving processing efficiency.

[0159] It should be understood that, in order to further improve the structural stability of the current collector 30, the structure after the release substrate 31 has been peeled off can be further processed to obtain the current collector 30.

[0160] In some embodiments, step S140 of method 100 may specifically include: after peeling off the release substrate 31 of the second structure 302, curing the second structure 302 after peeling off the release substrate 31 to obtain the current collector 30. This method can improve the structural stability and reliability of the current collector 30.

[0161] In some embodiments, the above-described curing of the second structure 302 after the release substrate 31 has been peeled off specifically includes: curing the second structure 302 after the release substrate 31 has been peeled off by static curing and / or hot rolling curing. The above curing method is simple and easy to implement.

[0162] It should be understood that the parameters involved in the curing method in the embodiments of this application can be set according to actual applications. For example, the curing temperature range when curing the second structure after the release substrate has been peeled off is [60℃, 150℃]. Setting a higher curing temperature, such as higher than or equal to 60℃, can improve the structural stability of the processed current collector 30; however, the curing temperature should not be too high, for example, it usually will not exceed 150℃, in order to reduce structural deformation, such as reducing the amount of deformation of the polymer substrate layer 33, and improving the reliability of the structure.

[0163] It should be understood that the dimensions of the current collector 30 prepared by method 100 in this application embodiment can be set according to actual applications. For example, the thickness T0 of the current collector 30 can be in the range of [3μm, 15μm] to meet design requirements. Setting the thickness T0 of the current collector 30 to be larger, for example, greater than or equal to 3μm, can improve the stability and structural strength of the current collector 30; however, the thickness T0 of the current collector 30 should not be too large, for example, the thickness T0 is usually less than or equal to 15μm, in order to reduce the volume of the current collector 30 and increase the energy density of the battery cell 20 using the current collector 30.

[0164] The preparation method of the current collector 30 according to the present application will be described below with reference to specific embodiments. The following description takes the preparation of a positive current collector as an example.

[0165] Specifically, in step 1, polyethylene terephthalate with a release agent coated on its surface at 50 μm is used as the release substrate 31. Vacuum evaporation aluminum is performed on the release substrate 31. The aluminum coating is the conductive layer 32. The thickness T2 of the conductive layer 32 is 1000 nm. After coating, it is rolled into a semi-finished roll (1).

[0166] Step 2: The surface of the metal layer of the semi-finished roll (1) is subjected to oxidation passivation treatment, and the resulting metal oxide is the passivation layer 321 with a thickness T5 of 10 nm, and the semi-finished roll (2) is obtained. The semi-finished roll (2) is the first structure 301.

[0167] Step 3: A polymer substrate layer 33 of polypropylene material and an adhesive layer 34 of maleic anhydride modified polypropylene material are used. A co-extruded polymer film (3) with adhesive on both sides is prepared by using a screw co-extrusion to form a film by combining polypropylene material and maleic anhydride modified polypropylene adhesive material. The total thickness is 8 μm, of which the thickness of the maleic anhydride modified polypropylene adhesive layer 34 is 2 μm.

[0168] Step 4: The co-extruded polymer film (3) and two rolls of semi-finished material (2) are fed together. The two rolls of semi-finished material (2) are located on opposite sides of the co-extruded polymer film (3). Specifically, after the surface of the co-extruded polymer film (3) is corona-treated, its surface dyne value is 42. Then, it is bonded to the corresponding semi-finished material (2) under hot rolling pressure at a bonding speed of 10 m / min and a bonding temperature of 140°C to obtain a semi-finished composite material (4), which is the second structure 302. The semi-finished composite material (4) includes: a release substrate 31, a conductive metal layer 32, an adhesive layer 34, a polymer substrate layer 33, an adhesive layer 34, a conductive metal layer 32, and a release substrate 31.

[0169] Step 5, the semi-finished composite roll (5) is carried out, and the release substrates 31 on both sides are peeled off and recycled at a 45° angle to obtain the composite current collector 30. The composite current collector 30 includes: a metal conductive layer 32, an adhesive layer 34, a polymer substrate layer 33, an adhesive layer 34 and a metal conductive layer 32.

[0170] Step 6: After the composite current collector 30 is cured at a high temperature of 150°C, the final product current collector 30 is obtained.

[0171] The current collector 30 prepared by the above method was tested and found that the resistivity of the aluminum in the current collector 30 did not deteriorate; after the current collector was bonded with corrugated tape, the conductive layer 32 on the surface did not fall off; and after being soaked in electrolyte at 60°C for 7 days, the conductive layer 32 still did not fall off after being bonded with corrugated tape.

[0172] According to some embodiments of this application, this application also provides a current collector 30, which is a current collector 30 prepared by the method 100 described in any of the above schemes.

[0173] According to some embodiments of this application, this application also provides a battery cell 20, which includes the current collector 30 described in any of the above embodiments.

[0174] According to some embodiments of this application, this application also provides a battery device, which includes a plurality of battery cells 20, each battery cell 20 including the current collector 30 described in any of the above embodiments.

[0175] According to some embodiments of this application, this application also provides an electrical device, including the battery device described in any of the above embodiments, and the battery device is used to provide electrical energy to the electrical device.

[0176] The electrical device can be any of the aforementioned devices or systems that utilize battery devices.

[0177] According to some embodiments of this application, referring to Figures 1 to 7, this application provides a method for preparing a current collector 30, comprising: metallizing a conductive layer 32 on the surface of a release substrate 31 to obtain a first structure 301; disposing an adhesive layer 34 on the surface of a polymer substrate layer 33; attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33 to obtain a second structure 302; and peeling off the release substrate 31 of the second structure 302 to obtain the current collector 30.

[0178] Metallizing a conductive layer 32 on the surface of a release substrate 31 includes forming the conductive layer 32 on the surface of the release substrate 31 by at least one of the following methods: vacuum evaporation, magnetron sputtering, and electroplating.

[0179] The adhesive layer 34 is disposed on the surface of the polymer substrate layer 33 by at least one of the following methods: microgravure coating, hot melt coating, screw extrusion, casting molding and coating molding.

[0180] The conductive layer 32 of the first structure 301 is attached to the surface of the adhesive layer 34 away from the polymer substrate layer 33, comprising: subjecting the surface of the adhesive layer 34 away from the polymer substrate layer 33 to corona treatment and / or plasma treatment, and then attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33. After the corona treatment and / or plasma treatment of the surface of the adhesive layer 34 away from the polymer substrate layer 33, the dyne value of the surface of the adhesive layer 34 away from the polymer substrate layer 33 is in the range of [38, 60].

[0181] The conductive layer 32 of the first structure 301 is attached to the surface of the adhesive layer 34 away from the polymer substrate layer 33, including: performing passivation treatment on the surface of the conductive layer 32 away from the release substrate 31; and attaching the passivated surface of the conductive layer 32 to the surface of the adhesive layer 34 away from the polymer substrate layer 33.

[0182] The conductive layer 32 of the first structure 301 is attached to the surface of the adhesive layer 34 away from the polymer substrate layer 33 by means of single-roller hot pressing or double-roller hot pressing.

[0183] The surface energy of the release substrate 31 ranges from 0 to 35.

[0184] Peeling the release substrate 31 of the second structure 302 to obtain the current collector 30 includes: after peeling off the release substrate 31 of the second structure 302, curing the second structure 302 with the release substrate 31 peeled off to obtain the current collector 30. Curing the second structure 302 with the release substrate 31 peeled off includes: curing the second structure 302 with the release substrate 31 peeled off by static curing and / or hot rolling curing.

[0185] The process of setting an adhesive layer 34 on the surface of the polymer substrate layer 33 includes: setting an adhesive layer 34 on two opposing surfaces of the polymer substrate layer 33 respectively; attaching the conductive layer 32 of the first structure 301 to the surface of the adhesive layer 34 away from the polymer substrate layer 33 to obtain the second structure 302, including: attaching the conductive layers 32 of the two first structures 301 to the surfaces of the adhesive layers 34 located on the two surfaces of the polymer substrate layer 33 away from the polymer substrate layer 33 respectively to obtain the second structure 302; and peeling off the release substrate 31 of the second structure 302 to obtain the current collector 30, including: peeling off the two release substrates 31 of the second structure 302 to obtain the current collector 30.

[0186] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing a current collector, characterized in that, include: A conductive layer is formed by metallizing the surface of a release substrate to obtain the first structure; An adhesive layer is provided on the surface of the polymer substrate layer; The conductive layer of the first structure is attached to the surface of the adhesive layer away from the polymer substrate layer to obtain the second structure; The release substrate of the second structure is peeled off to obtain the current collector.

2. The method according to claim 1, characterized in that, The step of attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: After corona treatment and / or plasma treatment of the surface of the adhesive layer away from the polymer substrate layer, the conductive layer of the first structure is attached to the surface of the adhesive layer away from the polymer substrate layer.

3. The method according to claim 2, characterized in that, After the corona treatment and / or plasma treatment are performed on the surface of the adhesive layer away from the polymer substrate layer, the dyne value of the surface of the adhesive layer away from the polymer substrate layer ranges from [38, 60].

4. The method according to any one of claims 1 to 3, characterized in that, The step of attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: The surface of the conductive layer away from the release substrate is passivated. The passivated surface of the conductive layer is attached to the surface of the adhesive layer away from the polymer substrate layer.

5. The method according to claim 4, characterized in that, The material of the passivated surface of the conductive layer includes metal oxides and / or chromates.

6. The method according to claim 4 or 5, characterized in that, After passivation treatment, the thickness of the passivation layer of the conductive layer ranges from [10nm, 100nm].

7. The method according to any one of claims 1 to 6, characterized in that, The step of attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer includes: The conductive layer of the first structure is bonded to the surface of the adhesive layer away from the polymer substrate layer by means of single-roller hot pressing or double-roller hot pressing.

8. The method according to claim 7, characterized in that, When the conductive layer of the first structure is bonded to the surface of the adhesive layer away from the polymer substrate layer: the bonding temperature ranges from [70℃ to 200℃], and / or the bonding speed ranges from [0.5m / min to 100m / min].

9. The method according to any one of claims 1 to 8, characterized in that, The peeling angle when peeling the release substrate of the second structure ranges from [30°, 180°].

10. The method according to any one of claims 1 to 9, characterized in that, The surface energy of the release substrate ranges from 0 to 35.

11. The method according to any one of claims 1 to 10, characterized in that, The process of peeling off the release substrate of the second structure to obtain the current collector includes: After peeling off the release substrate of the second structure, the second structure after peeling off the release substrate is cured to obtain the current collector.

12. The method according to claim 11, characterized in that, The curing of the second structure after the release substrate has been peeled off includes: The second structure, from which the release substrate has been peeled off, is cured by static curing and / or hot rolling curing.

13. The method according to claim 11 or 12, characterized in that, The curing temperature range for curing the second structure after the release substrate has been peeled off is [60℃, 150℃].

14. The method according to any one of claims 1 to 13, characterized in that, The provision of an adhesive layer on the surface of the polymer substrate layer includes: The adhesive layer is respectively disposed on two opposite surfaces of the polymer substrate layer; The step of attaching the conductive layer of the first structure to the surface of the adhesive layer away from the polymer substrate layer to obtain the second structure includes: The conductive layers of the two first structures are respectively attached to the surfaces of the adhesive layers located on two surfaces of the polymer substrate layer that are away from the polymer substrate layer to obtain the second structure; The process of peeling off the release substrate of the second structure to obtain the current collector includes: The two release substrates of the second structure are peeled off to obtain the current collector.

15. The method according to any one of claims 1 to 14, characterized in that, The release substrate satisfies: The release substrate material includes at least one of the following: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide, polybutylene terephthalate, other polyolefin resins, copper foil, aluminum foil, iron foil, and stainless steel foil; and / or, The thickness of the release substrate ranges from [20μm to 60μm].

16. A current collector, characterized in that, include: Conductive layer; Adhesive layer; A polymer substrate layer, wherein the adhesive layer is located between the conductive layer and the polymer substrate layer.

17. The current collector according to claim 16, characterized in that, The current collector comprises two conductive layers and two adhesive layers. The two adhesive layers are respectively located on two opposite surfaces of the polymer substrate layer, and the two conductive layers are respectively located on the surfaces of the adhesive layers away from the polymer substrate layer on the two surfaces of the polymer substrate layer.

18. The current collector according to claim 16 or 17, characterized in that, The materials of the conductive layer, the adhesive layer, and the polymer substrate layer satisfy at least one of the following conditions: The conductive layer is made of at least one of the following materials: copper, aluminum, titanium, cobalt, and nickel; The adhesive layer is made of at least one of the following materials: acrylate, polyurethane, polyester polyol, maleic anhydride modified polypropylene, maleic anhydride modified polyethylene, acrylic modified polypropylene, acrylic modified polyethylene, modified polyolefin resin, epoxy resin, ternary copolymer polyolefin, multi-component copolymer polyolefin resin, and polyamide. The polymer substrate layer is made of at least one of the following materials: polyethylene terephthalate, polyethylene and its copolymers, polypropylene and its copolymers, polytetrafluoroethylene, polyimide and polybutylene terephthalate.

19. The current collector according to any one of claims 16 to 18, characterized in that, The thickness of the conductive layer, the thickness of the adhesive layer, the thickness of the polymer substrate layer, and the thickness of the current collector satisfy at least one of the following conditions: The thickness of the conductive layer ranges from [500nm, 2000nm]; The thickness of the adhesive layer ranges from [0.4μm, 1.4μm]; The thickness of the polymer substrate layer ranges from [3μm, 14μm]; The thickness of the current collector is in the range of [3μm, 15μm].

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