Composite negative current collector, negative plate and solid-state battery
By employing a composite negative electrode current collector with a single-sided metal layer in lithium-ion batteries, and utilizing a thicker elastic substrate and copper foil, the problems of inconvenient welding and easy breakage of metal foil are solved, thereby improving welding efficiency and battery energy density, and enhancing safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-18
- Publication Date
- 2026-03-27
AI Technical Summary
The composite current collectors in existing lithium-ion batteries are inconvenient to weld when connected to the tabs, and the metal foil is too thin and easily breaks, affecting the energy density and welding reliability of the battery.
A composite negative electrode current collector with a metal layer on one side is adopted, a thick elastic substrate is used as a buffer layer, and the thickness is reduced at the electrode connection. Combined with copper foil and anti-corrosion layer, welding efficiency and battery energy density are improved.
It simplifies the welding process, reduces the risk of metal layer fracture, improves welding reliability and battery energy density, and enhances battery safety performance.
Smart Images
Figure CN224053142U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to lithium battery technical field, especially relate to a kind of composite negative electrode current collector, negative plate and solid-state battery. BACKGROUND
[0002] With the development and progress of science and technology, lithium ion battery is increasingly widely applied in power, energy storage, 3C and other fields, and the market requires higher and higher energy density of lithium ion battery.
[0003] Generally, lithium ion battery uses pure metal foil as current collector, but the pure metal foil as current collector is too thin to be welded with tab, so composite current collector is used, and the existing composite current collector usually includes elastic substrate layer and metal material layer arranged on both sides of the elastic substrate. This composite current collector needs to connect the metal material layers on both sides or make the tab penetrate through the whole current collector when connecting with the tab, which is very inconvenient for welding process.
[0004] Therefore, the market urgently needs a technical solution to solve the above problems. UTILITY MODEL CONTENT
[0005] To solve the above technical problems, a composite negative electrode current collector, a negative plate and a solid-state battery are disclosed in the utility model, and the technical scheme of the utility model is implemented as follows:
[0006] The first aspect of the utility model discloses a composite negative electrode current collector, which comprises an elastic substrate and a metal layer arranged on one side of the elastic substrate.
[0007] The elastic substrate comprises an elastic substrate main body part and an elastic substrate tab connecting part.
[0008] The thickness of the elastic substrate main body part is 300-500 μm.
[0009] The thickness of the elastic substrate tab connecting part is less than that of the elastic substrate main body part.
[0010] The utility model discloses only set up metal layer in the single side of elastic base material, compared with traditional two -sided metal layer, the utility model discloses need not consider the problem that the metal layer of upper and lower sides is conducted and then welds with the pole lug or the problem that the metal layer of upper and lower sides all need to weld with the pole lug separately, and the preparation is more convenient, second, the elastic base material in the application is thicker than the thickness of conventional elastic base material, and it can be used as a buffer layer, reduce the problem of the volume expansion of battery when charging and discharging, make the metal layer not easy to break, and also can provide support for the part of metal layer and pole lug connection, solve the problem that the conventional metal layer is thin and is easy to weld when welding with the pole lug. However, due to the thickness of the elastic base material is thicker than the conventional elastic base material, in order to facilitate the welding of the pole lug, therefore, the thickness of the elastic base material pole lug connecting part needs to be thinned to a certain extent, and the specific thinning degree is controlled in combination with the overall thickness of the elastic base material and the material type of the pole lug and other factors.
[0011] In specific application, the thickness of the elastic base material main body part can be selected as 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, 420 μm, 450 μm, 500 μm, which are only examples and not limited.
[0012] In specific application, the material of the elastic base material can be selected from one or several of PET / PP / PI, which are only examples and not limited.
[0013] Preferably, the metal layer comprises a metal layer main body part and a metal layer pole lug connecting part.
[0014] The metal layer main body part is correspondingly arranged on the elastic base material main body part, and the metal layer pole lug connecting part is correspondingly arranged on the elastic base material pole lug connecting part.
[0015] Further, in order to improve the welding effect, the cross section of the pole lug connecting part of the elastic base material in the thickness direction can be rectangular, trapezoidal or triangular, which can support the metal layer pole lug connecting part, reduce the possibility of damage caused by the welding process, and improve the welding rate.
[0016] It should be noted that the shape of the cross section mentioned above is only an example and not limited. Any known shape that can support the metal layer pole lug connecting part is within the scope of the utility model.
[0017] In specific application, the metal layer is a copper foil.
[0018] The copper foil has good electrical conductivity and thermal conductivity, which can effectively improve the energy density and charging and discharging efficiency of the battery, so it is a common current collector material for negative electrodes.
[0019] The method for disposing the copper foil on the elastic substrate includes, but is not limited to, a physical vapor deposition method, an electroplating method or a chemical plating method.
[0020] In actual operation, any one of the above methods or a combination of two or more thereof can be selected to realize the combination of the copper foil and the elastic substrate.
[0021] Preferably, the composite negative current collector further comprises an anti-corrosion layer disposed on the side of the metal layer away from the elastic substrate.
[0022] As a commonly used negative current collector, the copper foil will be corroded when it is applied to a solid electrolyte system, especially a sulfide solid electrolyte system or a halide solid electrolyte system, which further leads to premature failure of the battery. At the same time, the commonly used material PET as the elastic substrate also has poor corrosion resistance. Therefore, disposing an anti-corrosion layer at the metal layer can solve the above problems and make the negative electrode sheet have both energy density and safety performance.
[0023] In specific applications, the anti-corrosion layer can be selected from one or more of a nickel foil, a chromium foil and a stainless steel foil. The above are only examples and are not limiting.
[0024] Preferably, the anti-corrosion layer is disposed on the main body part of the metal layer.
[0025] Preferably, the anti-corrosion layer is also disposed on the tab connecting part of the metal layer.
[0026] In specific applications, the anti-corrosion layer can be disposed only on the main body part of the metal layer, or can cover the main body part and the tab connecting part of the metal layer.
[0027] Preferably, the thickness of the main body part of the metal layer is the same as the thickness of the tab connecting part of the metal layer.
[0028] Preferably, the thickness of the main body part of the metal layer is smaller than the thickness of the tab connecting part of the metal layer.
[0029] In specific applications, the thickness of the tab connecting part of the metal layer can be the same as the thickness of the main body part of the metal layer for easy preparation, or the thickness of the tab connecting part of the metal layer can be greater than the thickness of the main body part of the metal layer to prevent the problems of welding through or virtual welding and increase the defective rate.
[0030] The second aspect of the utility model discloses a negative electrode sheet, the negative electrode sheet includes the composite negative current collector disclosed in the first aspect of the utility model, and further includes a negative active material layer disposed on the composite negative current collector.
[0031] Preferably, the negative active material layer is disposed on the side of the anti-corrosion layer away from the metal layer.
[0032] In a specific application, the negative electrode active material layer includes a negative electrode active material, a conductive agent, and a binder. The negative electrode active material may optionally include any one or a combination of at least two of artificial graphite, natural graphite, microcrystalline graphite, soft carbon, and hard carbon. The above are all common negative electrode active materials in the art, and are only examples, not limitations.
[0033] In a specific application, the conductive agent includes any one or a combination of at least two of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers. The above are all common conductive agents in the art, and are only examples, not limitations.
[0034] In a specific application, the binder includes any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polystyrene, polyoxymethylene, polycarbonate, polyamide, acrylic plastics, other polyolefins and their copolymers, polysulfone, polyphenylene ether, or carboxymethyl cellulose. The above are all common binders in the art, and are only examples, not limitations.
[0035] In some preferred applications, the binder is polytetrafluoroethylene or polyvinyl chloride.
[0036] A third aspect of the present utility model discloses a solid-state battery, including a positive electrode sheet, a solid electrolyte layer, and the negative electrode sheet disclosed in the second aspect of the present utility model, which are arranged in sequence.
[0037] The solid electrolyte includes a sulfide solid electrolyte and / or a halide solid electrolyte.
[0038] In a specific application, the halide solid electrolyte can be selected from: Li2CdC
[0037] , 0.4 , x , 12 , 1-x ,
[0039] , 0.3 , l4 ,
[0038] , 10 , 0.6 , 3.4 , x , I4 , <00(00015>, l4 , 9.6 , , 11.7 , 、Li2MgC l4 、Li2Cd I4 、Li2ZnI4、Li3OCl、LiI、Li5ZnI4、Li3OCl 1-x Br x (where 0 < x < 1) of at least one.
[0039] In a specific application, the sulfide solid electrolyte can be selected from: Li2S-P2S5、Li2S-P2S5-MS x (where M is Si, Ge, and Sn and 0 ≤ x ≤ 2)、Li 3.4 Si 0.4 P 0.6 S4、Li 10 GeP2S 11.7 O 0.3 、Li 9.6 P3S 12 、Li7P3S 11Li9P3S9O3, Li 10.35 Si 1.35 P 1.65 S 12 Li 9.81 Sn 0.81 P 2.19 S 12 Li 10 (Si 0.5 Ge 0.5 P2S 12 Li (Ge 0.5 Sn 0.5 P2S 12 Li(Si) 0.5 Sn 0.5 PS 12 Li 10 GeP2S 12 (LGPS), Li6PS5X (where X is Cl, Br, or I), Li7P2S8I, Li 10.35 Ge 1.35 P 1.65 S 12 Li 3.25 Ge 0.25 P 0.75 S4, Li 10 SnP2S 12 Li 10 SiP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 , (1-x) P2S 5-x At least one of Li2S (where 0.5 ≤ x ≤ 0.7).
[0040] In specific applications, the solid electrolyte can be any one of the halide solid electrolytes mentioned above, or any one of the sulfide solid electrolytes, or any combination of at least one halide solid electrolyte and at least one sulfide solid electrolyte. This invention does not impose any limitations in this regard.
[0041] In specific applications, the positive electrode sheet includes a positive electrode active material, a conductive agent, and a binder. The positive electrode active material can be selected from any one or a combination of at least two of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium iron phosphate, lithium titanate, or lithium-rich manganese elastic base materials. These are all common positive electrode active materials in the art, and are merely examples, not limitations.
[0042] In this invention, the negative electrode sheet adopts a composite negative electrode current collector structure. The metal layer is only set on one side of the elastic substrate, and the thickness of the elastic substrate is much greater than that of the conventional elastic substrate. Therefore, it can be used as a buffer layer and can also provide support for the tab connection of the metal layer, improving the welding efficiency. This invention also reduces the thickness of the elastic substrate at the tab connection, which does not affect its supporting function and makes welding and preparation more convenient. Attached Figure Description
[0043] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0044] Identical parts are indicated by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions toward or away from the geometric center of a specific part, respectively.
[0045] Figure 1 A schematic diagram of a composite negative electrode current collector embodiment;
[0046] Figure 2 A schematic diagram of another embodiment of a composite negative electrode current collector;
[0047] Figure 3 for Figure 1 or Figure 2 Top view of the embodiment shown.
[0048] In the above figures, the figure numbers indicate the following:
[0049] 1. Main body of the metal layer;
[0050] 2. Elastic substrate main body;
[0051] 3. Metal layer tab connection part;
[0052] 4. Elastic substrate electrode tab connection part;
[0053] 5. Polar ears;
[0054] 6. Anti-corrosion layer. Detailed Implementation
[0055] The technical solutions of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.
[0056] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specific embodiments are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.
[0057] In the description of the specific embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.
[0058] In the present application, "embodiments" means that the specific features, structures or properties described in combination with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.
[0059] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents a "or" relationship between the front and rear associated objects.
[0060] Throughout this document, numerical values represent approximate measurements or limits to encompass minor deviations from a given value and embodiments having about the noted value and embodiments having the noted exact value. Except in the Examples provided at the end of the DETAILED DESCRIPTION, all numerical values of parameters (e.g., of quantities or conditions) in this specification, including the attached claims, are to be interpreted as approximations and are employed as terms of approximation one with ordinary skill in the art would understand to be a substantially representative of the value of the criteria with some tolerances, with the exact value understood to be within the scope of the criteria. The term "about" indicates that the stated numerical value is permitted to vary from the exact value by some minor amount (is close to the exact value to some degree; is approximately or reasonably close to the value; is nearly). If the imprecision provided by "about" is not otherwise understood in the art to have this ordinary meaning, then "about" as used in the present document indicates at least the variations that can be produced by ordinary methods of measuring and using such parameters. For example, "about" can include variations of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%.
[0061] In addition, the disclosure of ranges includes all values and further divisions of ranges within the entire range, including the endpoints and subranges given for the ranges.
[0062] Embodiments of the present document will be described more particularly below by way of examples. It is to be noted that the embodiments of the present document are not limited only to these examples.
[0063] Example 1
[0064] This example discloses a composite negative electrode current collector as shown in Figure 1 and Figure 3 The composite negative electrode current collector includes an elastic substrate and a metal layer arranged on one side of the elastic substrate; the elastic substrate is a pet material; the elastic substrate includes an elastic substrate main body part 2 and an elastic substrate tab connecting part 4; the thickness of the elastic substrate main body part 2 is 300 μm; the thickness of the elastic substrate tab connecting part 4 is 120 μm. The metal layer includes a metal layer main body part 1 and a metal layer tab connecting part 3; the metal layer main body part 1 is arranged on the elastic substrate main body part 2, and the metal layer tab connecting part 3 is arranged on the elastic substrate tab connecting part 4; an anti-corrosion layer 6 is arranged on the side of the metal layer main body part 1 away from the elastic substrate main body part 2. In this example, the metal layer is a copper foil, the anti-corrosion layer is a stainless steel foil, the thickness of the metal layer main body part 1 and the metal layer tab connecting part 3 is the same, and the anti-corrosion layer 6 is arranged only on the metal layer main body part 1.
[0065] The preparation process of this example is as follows:
[0066] First, the PET material is selected to make the elastic base material, wherein the elastic base material includes an elastic base material main body part 2 and an elastic base material tab connecting part 4, the elastic base material is unwound on a magnetron sputtering coating device for coating, a metal layer is formed, the metal layer is a copper foil, wherein the metal layer includes a metal layer main body part 1 and a metal layer tab connecting part 3, the magnetron sputtering coating device is coated again, an anti-corrosion layer 6 is formed on the metal layer, a composite negative electrode current collector is formed, and then the tab 5 is ultrasonically welded at the metal layer tab connecting part 3 of the composite negative electrode current collector, wherein the welding amplitude is 90%-100%, and the welding pressure is 0.5Mpa-1Mpa.
[0067] Example 2
[0068] The embodiment discloses a composite negative electrode current collector as shown in Figure 2 and Figure 3 The composite negative electrode current collector includes an elastic base material and a metal layer arranged on one side of the elastic base material, the elastic base material is a PET material, the elastic base material includes an elastic base material main body part 2 and an elastic base material tab connecting part 4, the thickness of the elastic base material main body part 2 is 500μm, and the thickness of the elastic base material tab connecting part 4 is 200μm. The metal layer includes a metal layer main body part 1 and a metal layer tab connecting part 3, the metal layer main body part 1 is arranged on the elastic base material main body part 2, the metal layer tab connecting part 3 is arranged on the elastic base material tab connecting part 4, and the metal layer main body part 1 is provided with an anti-corrosion layer 6 on the side away from the elastic base material main body part 2. In the embodiment, the metal layer is a copper foil, and the anti-corrosion layer is a nickel foil. In the embodiment, the thickness of the metal layer tab connecting part 3 is greater than the thickness of the metal layer main body part 1, so that welding through the metal layer can be prevented. The preparation process of the embodiment is the same as that of example 1.
[0069] It should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A composite negative electrode current collector, characterized by, The metal layer is arranged on one side of the elastic substrate. The elastic substrate comprises an elastic substrate main body part and an elastic substrate tab connecting part. The thickness of the elastic substrate main body part is 300-500 μm. The thickness of the elastic substrate tab connecting part is less than that of the elastic substrate main body part.
2. The composite negative current collector according to claim 1, wherein The metal layer comprises a metal layer main body part and a metal layer tab connecting part. The metal layer main body part is arranged on the elastic substrate main body part, and the metal layer tab connecting part is arranged on the elastic substrate tab connecting part.
3. The composite negative current collector according to claim 2, wherein The composite negative electrode current collector further comprises an anticorrosion layer arranged on the side of the metal layer away from the elastic substrate.
4. The composite negative current collector according to claim 3, wherein The anticorrosion layer is arranged on the metal layer main body part.
5. The composite negative current collector of claim 3, wherein The anticorrosion layer is further arranged on the metal layer tab connecting part.
6. The composite negative current collector of claim 2, wherein The thickness of the metal layer main body part is the same as that of the metal layer tab connecting part.
7. The composite negative current collector of claim 2, wherein The thickness of the metal layer main body part is less than that of the metal layer tab connecting part.
8. A negative electrode sheet characterized by comprising: The composite negative electrode current collector further comprises a negative electrode active material layer arranged on the composite negative electrode current collector.
9. The negative electrode sheet according to claim 8, characterized by The negative electrode active material layer is arranged on the side of the anticorrosion layer away from the metal layer.
10. A solid state battery, characterized by, The battery comprises a positive electrode tab, a solid-state electrolyte layer and the negative electrode tab of claim 9 arranged in sequence.