Composite current collector, cell, and battery

Abstract

The utility model provides a kind of composite current collector, battery and electric core, wherein, composite current collector, including: current collector body, current collector body includes substrate layer and the metal layer being arranged in substrate layer at least one side, wherein, the ratio a between the thickness of substrate layer and the elongation b of current collector body thickness satisfies:1.2≤a×b≤2.4.The technical scheme of the application effectively solves the problem that the area not coated with active material is prone to warping in the related art.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a composite current collector, a battery cell, and a battery. Background Technology

[0002] In the field of lithium-ion battery manufacturing, composite current collectors are a key material that plays a crucial role in battery performance and manufacturing processes. Composite current collectors are typically composed of a metal layer and a polymer substrate layer.

[0003] In related technologies, composite current collectors need to be rolled after being coated with active materials. During the rolling process, areas not coated with active materials are prone to warping. Utility Model Content

[0004] The main objective of this invention is to provide a composite current collector, a battery cell, and a battery to solve the problem of warping in areas not coated with active materials in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a composite current collector is provided, comprising: a current collector body, the current collector body including a substrate layer and a metal layer disposed on at least one side of the substrate layer, wherein the ratio a of the thickness of the substrate layer to the thickness of the current collector body and the elongation b of the current collector body satisfy the following condition: 1.2≤a×b≤2.4.

[0006] According to another aspect of the present invention, a battery cell is provided, comprising: a composite current collector; an active material layer disposed on a metal layer of the composite current collector, wherein the composite current collector and the active material layer corresponding to the active material layer form an electrode; and a blank area disposed on the composite current collector and located on the side of the active material layer, wherein the blank area forms an electrode tab, and the thickness of the composite current collector corresponding to the blank area gradually decreases in the direction away from the active material layer; wherein the composite current collector is the aforementioned composite current collector.

[0007] According to another aspect of the present invention, a battery cell is provided, comprising: a composite current collector; an active material layer disposed on a metal layer of the composite current collector, wherein the composite current collector and the active material layer corresponding to the active material layer form an electrode; a blank area disposed on the composite current collector and located on the side of the active material layer, the blank area forming an electrode tab, wherein the thickness of the composite current collector corresponding to the blank area gradually decreases in the direction away from the active material layer; wherein the ratio of the area of ​​the electrode tab to the total area of ​​the reinforcing structure on the electrode tab is c, the ratio c being between 5% and 25%, and / or the ratio of the total area of ​​the reinforcing structure on the electrode to the area of ​​the composite current collector is d, the ratio d being between 3% and 20%; the composite current collector is the aforementioned composite current collector.

[0008] According to another aspect of the present invention, a battery is provided, including a cell, wherein the cell is the aforementioned cell.

[0009] The present invention provides a current collector body comprising a substrate layer and a metal layer disposed on the substrate layer. The ratio 'a' of the thickness of the substrate layer to the thickness of the current collector body and the elongation 'b' of the current collector body satisfy the following condition: 1.2 ≤ a × b ≤ 2.4. By setting the above ratio, warping in areas not coated with active material can be avoided, thereby improving the quality of the composite current collector. Therefore, the present invention effectively solves the problem of warping in areas not coated with active material in related technologies. Attached Figure Description

[0010] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0011] Figure 1 A side view schematic diagram of an embodiment of the composite current collector according to the present invention is shown;

[0012] Figure 2 It shows Figure 1 A three-dimensional structural diagram of the reinforced structure of the composite current collector;

[0013] Figure 3 It shows Figure 1 A three-dimensional structural diagram of another reinforced structure for composite current collectors;

[0014] Figure 4 A three-dimensional structural schematic diagram of an embodiment of the battery cell according to the present invention is shown;

[0015] Figure 5 It shows Figure 2 A top-view diagram of the battery cell.

[0016] The above figures include the following reference numerals:

[0017] 10. Current collector body; 11. Substrate layer; 12. Metal layer; 13. Reinforcing structure; 20. Active material layer; 30. Blank area. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0021] like Figure 1 As shown, in this embodiment, the composite current collector includes a current collector body 10. The current collector body 10 includes a substrate layer 11 and a metal layer 12 disposed on at least one side of the substrate layer 11, wherein the ratio a of the thickness of the substrate layer 11 to the thickness of the current collector body 10 and the elongation b of the current collector body 10 satisfy the following condition: 1.2 ≤ a × b ≤ 2.4.

[0022] Applying the technical solution of this embodiment, the current collector body 10 includes a substrate layer 11 and a metal layer 12 disposed on the substrate layer 11. The ratio 'a' of the thickness of the substrate layer 11 to the thickness of the current collector body 10 and the elongation 'b' of the current collector body 10 satisfy the following condition: 1.2 ≤ a × b ≤ 2.4. By setting the above ratio, warping of areas not coated with active material can be avoided, thereby improving the quality of the composite current collector. Therefore, the technical solution of this embodiment effectively solves the problem of warping easily occurring in areas not coated with active material in related technologies.

[0023] Specifically, by precisely controlling the ratio 'a' of the thickness of the substrate layer 11 to the thickness of the current collector body 10 and the elongation 'b' of the current collector body 10, the problem of warping easily occurring in the uncoated area of ​​the composite current collector after the active material layer is coated can be solved. That is, by adjusting this ratio, the deformation recovery characteristics of the composite current collector under stress can be optimized. Even under large elongation deformation, the composite current collector can maintain good shape stability, thereby avoiding tab warping and edge curling / breakage. This significantly improves the processing performance of the composite current collector in battery manufacturing, reduces production defects caused by warping, and improves the overall quality and production yield of the battery.

[0024] It should be noted that if a×b≤1.2, the composite current collector is prone to band breakage during use. If a×b>2.4, it will lead to more severe warping.

[0025] like Figure 1 As shown, in this embodiment, the ratio a is between 0.4 and 0.8, and the elongation b is between 1.5% and 5%. By setting specific ranges for the ratio a and the elongation b, the elongation performance of the composite current collector can be controlled more precisely, ensuring its processing stability and reliability during battery manufacturing. That is, specific ranges for the ratio and elongation can balance the elongation and shape stability of the composite current collector, avoiding warping caused by excessive elongation or breakage caused by insufficient elongation.

[0026] Specifically, the ratio 'a' mentioned above can be 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, or other values, and the elongation 'b' can be 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or other values.

[0027] like Figure 1 As shown, in this embodiment, the metal layer 12 is made of copper or aluminum. Copper or aluminum has good electrical conductivity and appropriate ductility, which can meet the application requirements of composite current collectors in batteries. Furthermore, the high conductivity of copper and aluminum helps to reduce the internal resistance of the battery and improve the charging and discharging efficiency of the battery.

[0028] like Figure 1 As shown, in this embodiment, the substrate layer 11 is made of any one of polyethylene terephthalate, polypropylene, or polyimide. Polyethylene terephthalate, polypropylene, or polyimide all possess good insulation properties and high mechanical strength, effectively supporting the metal layer 12 while exhibiting good durability in a battery environment.

[0029] like Figure 2 and Figure 3 As shown, in this embodiment, a reinforcing structure 13 is provided on the metal layer 12. The reinforcing structure enhances the mechanical strength and stability of the metal layer.

[0030] It should be noted that the aforementioned reinforcing structure 13 can be at least one of a raised structure, a recessed structure, or a reinforcing rib. Specifically, the reinforcing structure 13 can be dot-shaped, strip-shaped, wavy, serrated, etc.

[0031] Specifically, Figure 2 The reinforcing structure 13 is shown to be a protruding structure. Figure 3 The reinforcing structure 13 is shown to be a recessed structure.

[0032] like Figure 1 As shown, in this embodiment, the thickness of the substrate layer 11 is between 2 μm and 12 μm. Setting the thickness of the substrate layer 11 within a specific range effectively balances the mechanical and electrical properties of the composite current collector, ensuring its stability and reliability in a battery environment. Specifically, the appropriate selection of the thickness of the substrate layer 11 can affect the elongation and elastic modulus of the composite current collector, thereby affecting its deformation recovery ability during processing and its stability under battery operating conditions.

[0033] Specifically, the thickness of the substrate layer 11 can be 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm or other values.

[0034] like Figure 1As shown, in this embodiment, the thickness of the metal layer 12 is between 1 μm and 3 μm. Setting the thickness of the metal layer 12 within a specific range effectively balances the conductivity and mechanical stability of the composite current collector, ensuring its efficient current transmission and resistance to processing stress in a battery environment. Specifically, the appropriate selection of the thickness of the metal layer 12 directly affects the resistivity and ductility of the composite current collector. Too thin a layer may lead to increased resistance, affecting the battery's charge and discharge efficiency; too thick a layer may reduce ductility, increasing processing difficulty and cost.

[0035] Specifically, the thickness of the aforementioned metal layer 12 can be 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, or other values.

[0036] According to another aspect of this application, a battery cell is provided, such as... Figure 4 and Figure 5 As shown, the battery cell of this embodiment includes: a composite current collector; an active material layer 20 disposed on the metal layer 12 of the composite current collector, with the composite current collector and the active material layer 20 forming an electrode; and a blank area 30 disposed on the composite current collector and located on the side of the active material layer 20, forming an electrode tab. The thickness of the composite current collector corresponding to the blank area 30 gradually decreases in the direction away from the active material layer 20. The composite current collector is the composite current collector described above. By using the composite current collector in the battery cell, the problem of warping easily occurring in the uncoated area after the composite current collector is coated with the active material layer can be effectively solved. Furthermore, by gradually decreasing the thickness of the composite current collector on the blank area 30 along the side away from the active material layer 20, the rebound of the blank area 30 can be reduced, warping can be avoided, thereby improving the manufacturing yield and efficiency of the battery.

[0037] According to another aspect of this application, a battery cell is provided, such as... Figure 4 and Figure 5As shown, the battery cell of this embodiment includes: a composite current collector; an active material layer 20 disposed on the metal layer 12 of the composite current collector, with the composite current collector and the active material layer 20 forming an electrode; a blank area 30 disposed on the composite current collector and located on the side of the active material layer 20, the blank area 30 forming a tab, and the thickness of the composite current collector corresponding to the blank area 30 gradually decreasing in the direction away from the active material layer 20; wherein, the ratio of the area of ​​the tab to the total area of ​​the reinforcing structure 13 on the tab is c, the ratio c being between 5% and 25%, and the ratio of the total area of ​​the reinforcing structure 13 on the electrode to the area of ​​the composite current collector is d, the ratio d being between 3% and 20%; the composite current collector is the aforementioned composite current collector. By providing reinforcing structures with different coverage rates on the active material layer 20 and the composite current collector corresponding to the blank area 30, the mechanical and electrical performance of the battery cell can be further optimized. Strengthening the control of structural coverage is based on the analysis of stress distribution and electrical contact performance of composite current collectors during battery manufacturing. By setting the enhanced structural coverage of the active material layer and blank area, the stress distribution of composite current collectors can be optimized, the risk of breakage during battery manufacturing can be reduced, and electrical contact performance can be enhanced to improve the electrical performance of the battery.

[0038] Specifically, the ratio c can be 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, or other ratios.

[0039] The ratio d can be 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, or other ratios.

[0040] According to another aspect of this application, a battery is provided, including a battery cell, wherein the battery cell is the aforementioned battery cell. By using the aforementioned battery cell in the battery, the problem that the uncoated area of ​​the composite current collector is prone to warping after the active material layer is coated during the battery manufacturing process can be effectively solved. By using the aforementioned battery cell, the stability and reliability of the battery during the manufacturing process can be ensured, avoiding problems such as tab warping and edge curling / breakage, thereby improving the manufacturing yield and efficiency of the battery.

[0041] The following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0042] [Battery]

[0043] The battery in this application is a secondary battery, also known as a rechargeable battery or storage battery, which refers to a battery that can be used again after being discharged by recharging to activate the active materials.

[0044] Typically, a secondary battery consists of a battery cell, an electrolyte, and a casing. The battery cell includes a positive electrode, a negative electrode, and a separator. The battery cell and electrolyte are assembled inside the casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, located between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, situated between the positive and negative electrodes, mainly serves to conduct active ions.

[0045] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cell. The cell is placed in a casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0046] [Positive electrode tablets]

[0047] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0048] This application does not impose any particular restrictions on the type of positive electrode active material for the positive electrode sheet. As an example, the positive electrode active materials in this application include lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0049] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0050] In this application, the binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. This application does not impose any particular limitation on the type of binder for the positive electrode sheet; the binder can be any conventional choice in the battery industry. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0051] This application does not impose any particular restrictions on the positive electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0052] [Negative electrode plate]

[0053] The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a silicon-based material. This application does not specifically limit the type of silicon-based material; the silicon-based material can be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material can be one or more of silicon-carbon composite negative electrode materials, silicon suboxide negative electrode materials, modified silicon suboxide negative electrode materials, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0054] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0055] This application does not specifically limit the type of negative electrode conductive agent. In some embodiments, as an example, the negative electrode conductive agent can be one or more of conventional negative electrode conductive agents such as acetylene black and carbon nanotubes. This application does not specifically limit the type of negative electrode binder. In some embodiments, as an example, the binder can be one or more of conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). In this application, the binder is preferably PAA, SBR, and CMC, and the mass ratio of PAA, SBR, and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0056] This application does not impose specific limitations on the type of negative electrode current collector. In some embodiments, as an example, the negative electrode current collector can be one of the conventional negative electrode current collectors such as copper foil.

[0057] Electrolyte

[0058] The electrolyte 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. As an example, the electrolyte in this application can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent; the electrolyte typically includes a lithium salt, and additives may also be added to the electrolyte.

[0059] Specifically, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0060] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0061] In some implementations, as an example, the additive may be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0062] [Septum]

[0063] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0064] In some embodiments, as an example, the diaphragm can be one of PP, PE, or PP / PF; the diaphragm can also be a structure in which a coating is formed on the surface of the base film, wherein the base film coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0065] In the description of this utility model, it should be understood that "multiple" means a quantity of two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0066] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0067] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0068] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A composite current collector, characterized in that, include: The current collector body (10) includes a substrate layer (11) and a metal layer (12) disposed on at least one side of the substrate layer (11), wherein the ratio a of the thickness of the substrate layer (11) to the thickness of the current collector body (10) and the elongation b of the current collector body (10) satisfy the following: 1.2≤a×b≤2.

4.

2. The composite current collector according to claim 1, characterized in that, The ratio a is between 0.4 and 0.8, and / or the elongation b is between 1.5% and 5%.

3. The composite current collector according to claim 1, characterized in that, The metal layer (12) is made of copper or aluminum.

4. The composite current collector according to claim 1, characterized in that, The substrate layer (11) is made of any one of polyethylene terephthalate, polypropylene, or polyimide.

5. The composite current collector according to claim 1, characterized in that, A reinforcing structure (13) is provided on the metal layer (12).

6. The composite current collector according to claim 1, characterized in that, The thickness of the substrate layer (11) is between 2μm and 12μm.

7. The composite current collector according to claim 1, characterized in that, The thickness of the metal layer (12) is between 1 μm and 3 μm.

8. A battery cell, characterized in that, The battery cell includes: Composite current collector; An active material layer (20) is disposed on the metal layer (12) of the composite current collector, and the composite current collector and the active material layer (20) corresponding to the active material layer (20) form an electrode. A blank area (30) is provided on the composite current collector and located on the side of the active material layer (20). The blank area (30) forms a tab. In the direction away from the active material layer (20), the thickness of the composite current collector corresponding to the blank area (30) gradually decreases. Wherein, the composite current collector is the composite current collector described in any one of claims 1 to 7.

9. A battery cell, characterized in that, The battery cell includes: Composite current collector; An active material layer (20) is disposed on the metal layer (12) of the composite current collector, and the composite current collector and the active material layer (20) corresponding to the active material layer (20) form an electrode. A blank area (30) is provided on the composite current collector and located on the side of the active material layer (20). The blank area (30) forms a tab. In the direction away from the active material layer (20), the thickness of the composite current collector corresponding to the blank area (30) gradually decreases. Wherein, the ratio of the area of ​​the electrode tab to the total area of ​​the reinforcing structure (13) on the electrode tab is c, and the ratio c is between 5% and 25%, and / or, the ratio of the total area of ​​the reinforcing structure (13) on the electrode to the area of ​​the composite current collector is d, and the ratio d is between 3% and 20%, and the composite current collector is the composite current collector of claim 5.

10. A battery, comprising a cell, characterized in that, The battery cell is the battery cell described in claim 8 or 9.

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