Negative pole piece and solid-state battery

Abstract

The utility model relates to a negative pole piece and a solid-state battery in the technical field of lithium battery, the negative pole piece comprises a negative pole current collector and a negative pole active material layer arranged on the negative pole current collector, the negative pole piece comprises an overhang area and a non-overhang area, the negative pole current collector is a composite current collector, and the overhang area is a non-overhang area. The composite current collector comprises a base material and a metal layer arranged in the non-overhang area, the negative current collector further comprises an anti-corrosion layer, at least part of the anti-corrosion layer is arranged in the overhang area, and the anti-corrosion layer is connected with the metal layer. According to the utility model, the metal layer is arranged in the non-overhang area, and the anti-corrosion layer is arranged in the overhang area, so that the corrosion of sulfide electrolyte and halide solid electrolyte to the negative pole piece can be reduced, and meanwhile, the composite negative current collector is adopted as the negative current collector, so that compared with the traditional copper foil current collector, the safety and the energy density are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery technical field, especially relates to a negative pole piece and solid state battery. BACKGROUND

[0002] In the lithium ion solid state battery, if the negative pole does not accept the position of lithium ion, lithium ion will be precipitated on the negative pole surface, forms lithium dendrite, pierces the diaphragm, causes the short circuit in the battery, and initiates the thermal runaway.

[0003] Therefore, when designing the lithium battery, the negative pole piece will exceed the positive pole piece in length and width direction certain length, and the area is larger than the positive pole piece, and the non-overlapping area of the positive pole piece and the negative pole piece is called overhang area, and the overlapping area of the positive pole piece and the negative pole piece is called non-overhang area.

[0004] The copper foil is used as the negative pole current collector of the lithium battery, and is easy to be corroded in the sulfide electrolyte system and halide electrolyte system, especially in the overhang area. Therefore, the market urgently needs a technical scheme to solve the above problems. UTILITY MODEL CONTENT

[0005] In order to solve the above technical problems, the utility model provides a negative pole piece and solid state battery, and the technical scheme of the utility model is implemented as follows:

[0006] The utility model discloses a negative pole piece, which comprises a negative pole current collector and a negative pole active material layer arranged on the negative pole current collector, and the negative pole piece comprises an overhang area and a non-overhang area.

[0007] The overhang area is a non-overlapping area of the negative pole piece and the positive pole piece, and the non-overhang area is an overlapping area of the negative pole piece and the positive pole piece.

[0008] The negative pole current collector is a composite current collector, and the composite current collector comprises a base material and a metal layer arranged on both sides of the base material along the thickness direction.

[0009] The metal layer is arranged in the non-overhang area, and the metal layer is a copper foil layer.

[0010] The negative pole current collector further comprises an anti-corrosion layer.

[0011] The anti-corrosion layer is also arranged on both sides of the base material along the thickness direction of the base material.

[0012] The anti-corrosion layer is at least partially arranged in the overhang area, and the anti-corrosion layer and the metal layer are connected.

[0013] Preferably, the metal layer is arranged in the non-overhang region, the width of the metal layer is the same as the width of the non-overhang region, and the corrosion-resistant layer is arranged in the overhang region, the width of the corrosion-resistant layer is the same as the width of the overhang region.

[0014] Preferably, the metal layer and the corrosion-resistant layer are arranged in the non-overhang region, and the corrosion-resistant layer is arranged in the overhang region.

[0015] Preferably, the width of the non-overhang region is d1, the width of the overhang region is d2, the width of the metal layer is d3, and the width of the corrosion-resistant layer is d4, wherein d1+d2=d3+d4, d2<d4, and d4-d2≦5%d1.

[0016] Preferably, the width of the overhang region is 0.2mm-2mm.

[0017] Preferably, the substrate is a sheet-shaped rectangle, and the thickness of the substrate is 3μm-8μm.

[0018] Preferably, the thickness of the metal layer and the corrosion-resistant layer is the same, and the thickness of the metal layer is 1μm-30μm.

[0019] Preferably, the thickness of the composite negative electrode current collector is 5μm-50μm.

[0020] The second aspect of the utility model provides a solid-state battery, the solid-state battery includes the positive pole piece, solid-state electrolyte layer and the negative pole piece of the first aspect of the utility model successively.

[0021] Preferably, the solid-state electrolyte layer includes any one or the laminated body of two of sulfide solid-state electrolyte layer and halide solid-state electrolyte layer.

[0022] The utility model has the advantages of:

[0023] The non-overhang region of the negative pole piece of the utility model uses copper foil as the current collector, and the overhang region uses the corrosion-resistant layer as the current collector, thereby solving the problem that the copper foil as the negative electrode current collector is easily corroded by sulfide electrolyte and halide electrolyte in the overhang region. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are only a part of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0025] Wherein the same parts are indicated by the same reference numerals. It should be noted that the words "front", "back", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings, and the words "bottom" and "top", "inner" and "outer" refer to the directions towards or away from the geometric center of a particular part.

[0026] Figure 1 Structure diagram of the cell unit of a solid-state battery embodiment;

[0027] Figure 2 Structure diagram of the composite negative electrode current collector in the solid-state battery shown in Figure 1

[0028] In the above drawings, each figure number mark represents:

[0029] 1, positive electrode current collector, 2, positive electrode active material layer, 3, solid-state electrolyte layer, 4, negative electrode active material layer, 5, corrosion protection layer, 6, metal layer, 7, base material. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described clearly and completely below by combining the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled 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.

[0032] ​In the description of the specific embodiments of the utility model, the technical terms "first", "second" and the like 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 utility model, the meaning of "a plurality of" is more than two, unless otherwise explicitly specified.

[0033] In the utility model, the "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the utility model. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the utility model can be combined with other embodiments.

[0034] In the description of the embodiments of the utility model, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the utility model generally indicates that the front and rear associated objects are in an "or" relationship.

[0035] Throughout the utility model, numerical values represent approximate measurements or limits of a range to encompass minor deviations from the given values and embodiments with approximately the mentioned values and embodiments with the mentioned exact values. In addition to the working examples provided at the end of the specific embodiments, all numerical values of parameters (e.g. quantities or conditions) in the specification (including the appended claims) should be understood in all cases to be modified by the term "about", regardless of whether "about" actually appears before the numerical value. "About" indicates that some minor inaccuracy exists in the stated numerical value (to some extent close to the exact value of the value stated; approximately or reasonably close to the value stated; almost). If the inaccuracy provided by "about" is not otherwise understood in the art in this ordinary meaning, "about" as used in the utility model at least indicates the variation that can be produced by ordinary methods of measuring and using such parameters. For example, "about" can include a variation 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 some aspects, optionally less than or equal to 0.1%.

[0036] In addition, the disclosure of the range includes all values within the entire range and the disclosure of the further divided range, including the endpoints and subranges given for these ranges.

[0037] In the design of the battery, if the negative electrode does not accept the position of lithium ions, lithium ions will be precipitated on the surface of the negative electrode to form lithium dendrites, pierce the separator, cause internal short circuit of the battery, and trigger thermal runaway, therefore, the negative electrode needs to have an overhang area in the design, copper foil and stainless steel foil are commonly used current collectors in lithium batteries, but in the battery with sulfide solid electrolyte or halide solid electrolyte, since the copper foil will react with the sulfide solid electrolyte and the halide solid electrolyte, causing corrosion of the copper foil, which seriously affects the service life and performance of the battery.

[0038] To solve the above problems, the first aspect of the utility model provides a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer arranged on the negative electrode current collector, the negative electrode sheet includes an overhang area and a non-overhang area, the negative electrode current collector is a composite current collector, the composite current collector includes a base material and a metal layer arranged on both sides of the base material along the thickness direction, the metal layer is arranged in the non-overhang area, the metal layer is a copper foil layer, the negative electrode current collector further includes an anti-corrosion layer, the anti-corrosion layer is also arranged on both sides of the base material along the thickness direction of the base material, the anti-corrosion layer is at least partially arranged in the overhang area, and the anti-corrosion layer and the metal layer are connected.

[0039] In practical application, the negative electrode active material includes one or more combinations of artificial graphite, natural graphite, microcrystalline graphite, soft carbon, hard carbon, pure silicon, silicon carbon and silicon oxygen. The above is only an example and is not limited.

[0040] In practical application, the anti-corrosion layer material can be selected from one or more combinations of stainless steel, nickel, chromium and nickel-chromium. The anti-corrosion layer can be arranged on the surface of the metal layer in the form of deposition, including but not limited to electroplating deposition, physical vapor deposition, chemical deposition, magnetron sputtering deposition and the like, or can be arranged in the form of adhesion. The above is only an example and is not limited.

[0041] The utility model adopts the negative electrode current collector of " sandwich " structure composite, the middle part is provided with the base material, the metal layer and the anti-corrosion layer are arranged on both sides of the base material, compared with using the metal layer and / or the anti-corrosion layer as the current collector, it has higher safety and energy density.

[0042] The utility model sets the copper foil in the non-overhang area to ensure that it does not directly contact the sulfide solid electrolyte or halide solid electrolyte, reduces the possibility of corrosion, the anti-corrosion layer is not corroded by the sulfide solid electrolyte or halide solid electrolyte, therefore, the anti-corrosion layer is arranged in the overhang area, when the anti-corrosion layer is made of stainless steel, it can also solve the problem that stainless steel is not easy to make wide, ensure the anti-corrosion effect and facilitate the processing of the current collector.

[0043] In some embodiments, the metal layer is provided in the non-overhang region, and the width of the metal layer is the same as the width of the non-overhang region; and the corrosion-resistant layer is provided in the overhang region, and the width of the corrosion-resistant layer is the same as the width of the overhang region.

[0044] In some embodiments, the metal layer and the corrosion-resistant layer are provided in the non-overhang region, and the corrosion-resistant layer is provided in the overhang region.

[0045] In some embodiments, the width of the non-overhang region is d1, the width of the overhang region is d2, the width of the metal layer is d3, and the width of the corrosion-resistant layer is d4, wherein d1+d2=d3+d4, d2

[0046] As long as the corrosion-resistant layer is provided in the overhang region, the corrosion-resistant layer can also extend into the non-overhang region, and limiting the length of the extension can ensure the energy density of the battery.

[0047] In some embodiments, the width of the overhang region is 0.2 mm-2 mm.

[0048] In practical applications, the width of the overhang region can be specifically selected as 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm. The above values are only examples and are not limiting.

[0049] Limiting the width of the overhang region can reduce the area of the overhang region, thereby reducing the influence of the overhang region on the energy density of the battery, and at the same time, limiting the width of the overhang region in this region can obtain better processing performance.

[0050] In some embodiments, the substrate is a sheet-shaped rectangle, and the thickness of the substrate is 3 μm-8 μm. In practical applications, the thickness of the substrate can be specifically selected as 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, or 8 μm. The above values are only examples and are not limiting.

[0051] In practical applications, the polymer material is used as the base material, which is lighter than metal, and the thickness of the base material is limited within this range. Without increasing the total thickness of the composite negative electrode current collector, the specific gravity of the composite negative electrode current collector can be reduced, so that the energy density of the battery can be improved.

[0052] In practical applications, the polymer material includes at least one of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyether ether ketone, polyimide, polyamide, polyethylene glycol, polyamide-imide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, poly methylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly(vinylidene fluoride-hexafluoropropylene), poly(vinylidene fluoride-co-trifluorochloroethylene), silicone, vinylon, polypropylene, polyethylene, polyvinyl chloride, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polyester, polysulfone and derivatives thereof, sodium carboxymethyl cellulose, styrene butadiene rubber, fluorinated rubber, polyvinyl alcohol, and polyvinylidene fluoride. The above are only examples and are not limited.

[0053] Generally, the melting point of the polymer material is lower than that of the metal. When the temperature of the battery rises to the melting point of the base material, the base material melts, causing the damage of the electrode sheet. Thus, the current can be cut off, thereby improving the safety of the battery. When the lithium ion battery is subjected to physical impact from the outside, especially impact from a sharp object or a heavy object, the metal layers on both sides of the composite negative electrode current collector are broken. The base material in the middle can prevent the broken surface from piercing the separator and contacting other places to cause short circuit by its own ductility. Thus, the problem of internal short circuit after the lithium ion battery is subjected to physical impact from the outside can be solved, and the safety performance of the battery is improved.

[0054] In some embodiments, the thickness of the metal layer and the corrosion-resistant layer is the same, and the thickness of the metal layer is 1 μm-30 μm.

[0055] In practical applications, the thickness can be specifically selected as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm. The above values are only examples and are not limited.

[0056] In some embodiments, the thickness of the composite negative electrode current collector is 5 μm-50 μm.

[0057] In practical applications, the thickness of the composite negative electrode current collector is 5-50 μm. In practical applications, the thickness of the composite negative electrode current collector can be selected as 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, 50 μm. The above values are only examples and are not limited.

[0058] The thickness of the metal layer, the corrosion-resistant layer and the composite negative electrode current collector is limited within the above range, so that the volume and capacity of the battery can be balanced and the capacity of the battery can be ensured.

[0059] The second aspect of the utility model discloses a kind of solid-state batteries, and the solid-state batteries include positive pole sheet, solid-state electrolyte layer and the negative pole sheet of the first aspect of the utility model successively arranged.

[0060] In practical applications, the positive electrode includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material can be selected from any one or a combination of at least two of lithium cobaltate, 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-based materials. The above are all common positive electrode active materials in the art, which are only examples and are not limited.

[0061] In practical applications, the positive electrode active material layer and the negative electrode active material layer can each independently include a binder. The binder can be any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyvinyl chloride, polystyrene, polyformaldehyde, polycarbonate, polyamide, acrylic plastic, other polyolefins and their copolymers, polysulfone, polyphenyl ether or carboxymethyl cellulose, and is preferably polytetrafluoroethylene or polyvinyl chloride. The above are all common binders in the art, which are only examples and are not limited.

[0062] In practical applications, the positive electrode active material layer and the negative electrode active material layer can each independently include a conductive agent. The conductive agent can be 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, which are only examples and are not limited.

[0063] In some embodiments, the solid-state electrolyte layer includes any one or a laminate of both of a sulfide solid-state electrolyte layer and a halide solid-state electrolyte layer.

[0064] In practical applications, the solid-state electrolyte layer can be only a single-layer sulfide solid-state electrolyte layer, which can also contain other solid-state electrolytes, the solid-state electrolyte layer can also be only a single-layer halide solid-state electrolyte layer, which can also contain other solid-state electrolytes, or the solid-state electrolyte layer can be a laminate including a sulfide solid-state electrolyte layer and a halide solid-state electrolyte layer, which can contain other solid-state electrolytes, and the above are only examples and are not limiting.

[0065] In practical applications, the sulfide solid-state electrolyte in the sulfide solid-state electrolyte layer can be specifically selected from Li2S-P2S5, Li2S-P2S5-LiX, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-2Z m S n , Li2S-GeS2, Li2S-SiS2-Li3PO4, and Li2S-SiS2-Li p MO q , wherein X is a halogen element, m, n, p, and q are positive numbers, Z is Ge, Zn, or Ga, and M is P, Si, Ge, B, Al, Ga, or In. The above are only examples and are not limiting.

[0066] In practical applications, the halide solid-state electrolyte in the halide solid-state electrolyte layer can be specifically selected from Li2ZrCl6, Li2CdCl l4 , Li2MgCl l4 , Li2Cd I4 , Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl 1-x Br x , wherein 0 < x < 1. The above are only examples and are not limiting.

[0067] It should be noted that the "at least one" in the utility model refers to a combination of two or more than two in addition to one, which is known in the art, and any combination known in the prior art is within the protection scope of the utility model.

[0068] The embodiments of the present application will be described in more detail by the following examples. It should be noted that the embodiments of the present application are not limited to these examples.

[0069] Example 1

[0070] In a specific embodiment 1, a solid-state battery comprises a positive current collector 1, a positive active material layer 2, a solid-state electrolyte layer 3, a negative active material layer 4 and a negative current collector arranged in sequence as shown in the figure; wherein the negative current collector is a composite current collector, comprising a substrate 7 and a metal layer 6 arranged on both sides of the substrate 7 and a corrosion-resistant layer 5 arranged on both sides of the substrate 7. Figure 1

[0071] In this embodiment, the metal layer 6 is a copper foil layer, the width of which is equal to the width of the non-overhang region, the corrosion-resistant layer 5 is a stainless steel layer, the width of which is equal to the width of the overhang region, and the thickness of which is the same as that of the metal layer 6 and is in contact with it, and the solid-state electrolyte layer 3 is a sulfide solid-state electrolyte layer.

[0072] In this embodiment, the preparation method of the solid-state electrolyte layer 3 is: placing the sulfide electrolyte Li7PS6 and the binder into a small mixing machine to mix uniformly by dry method to obtain a mixture, and rolling the mixture on a roller press multiple times to obtain the solid-state electrolyte layer 3.

[0073] Example 2

[0074] The difference between example 2 and example 1 is that the corrosion-resistant layer 1 in example 2 is a nickel layer, and the solid-state electrolyte layer 7 is a halide solid-state electrolyte Li2ZrCl6, and except for this, the other structures and the preparation method of the solid-state electrolyte in example 2 are exactly the same as in example 1.

[0075] Control group 1

[0076] The difference between example 1 and control group 1 is that the negative electrode sheet in control group 1 does not include a corrosion-resistant layer, and the other structures and the preparation method of the sulfide solid-state electrolyte are exactly the same as in example 1.

[0077] Control group 2

[0078] The difference between example 2 and control group 2 is that the negative electrode sheet in control group 2 does not include a corrosion-resistant layer, and the other structures and the preparation method of the halide solid-state electrolyte are exactly the same as in example 2.

[0079] After the battery is prepared, a total of four groups of samples are taken from example 1, example 2, control group 1 and control group 2, and the number of samples in each group is 10.

[0080] The battery corrosion test and the battery cycle performance test are carried out on the four groups of samples respectively, and the data of each group of samples is averaged after the test is completed.​

[0081] The test method is as follows:

[0082] 1) Battery corrosion test

[0083] Four groups of lithium ion batteries were charged and discharged at 1C rate for 500 cycles, then the negative electrode sheets in each group of batteries were taken out, the active material was washed off, and the corrosion of the negative electrode current collector was observed.

[0084] 2) Battery cycle performance test

[0085] The charge and discharge potential range is 3.0V-4.3V, the charge current is 1C to 4.3V, 4.3V constant voltage charging to the cutoff current ≤0.05C, standing for 5 minutes, 1C discharging to 3.0V, standing for 5 minutes; such cycle charging and discharging, test the cycle performance at room temperature (25℃), record the average value of cycle capacity retention rate after 50 cycles.

[0086] The test results are shown in the table:

[0087] Group Positive electrode Negative electrode Electrolyte Corrosion condition Battery cycle performance Example 1 Al foil Cu + SUS + substrate Li7PS6 No 500 clc @ 80% Example 2 Al foil Cu + Ni + substrate Li2ZrCl6 No 600 clc @ 80% Comparative Example 1 Al foil Cu + substrate Li7PS6 Yes 100 clc @ 80% Comparative Example 2 Al foil Cu + substrate Li2ZrCl6 Yes 65 clc @ 80%

[0088] As can be seen from the examples and comparative examples, by setting the corrosion prevention layer in the overhang area and the metal layer in the non-overhang area as the composite negative electrode current collector, the corrosion of the composite negative electrode current collector can be reduced, and the cycle performance of the battery can be improved.

[0089] It should be pointed out that the above only describes the preferred embodiments of the present application, and is not intended to limit the present application, 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 negative electrode sheet comprising a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector, characterized by: The negative electrode tab includes an overhang region and a non-overhang region. The overhang region is a region where the negative electrode tab does not overlap with the positive electrode tab, and the non-overhang region is a region where the negative electrode tab overlaps with the positive electrode tab. The negative electrode current collector is a composite current collector including a base material and a metal layer provided on both sides of the base material along the thickness direction. The metal layer is a copper foil layer provided in the non-overhang region. The negative electrode current collector further includes an anticorrosion layer. The anticorrosion layer is also provided on both sides of the base material along the thickness direction of the base material. The anticorrosion layer is at least partially provided in the overhang region, and the anticorrosion layer and the metal layer are in contact with each other.

2. The negative electrode sheet according to claim 1, characterized by The metal layer is provided in the non-overhang region, and the width of the metal layer is the same as the width of the non-overhang region, and the anticorrosion layer is provided in the overhang region, and the width of the anticorrosion layer is the same as the width of the overhang region.

3. The negative electrode sheet according to claim 1, wherein The metal layer and the anticorrosion layer are provided in the non-overhang region, and the anticorrosion layer is provided in the overhang region.

4. The negative electrode sheet according to claim 3, characterized by The width of the non-overhang region is d1, the width of the overhang region is d2, the width of the metal layer is d3, and the width of the anticorrosion layer is d4, wherein d1+d2=d3+d4, d2 5. The negative electrode sheet according to claim 1, wherein The width of the overhang region is 0.2 mm to 2 mm.

6. The negative electrode sheet according to claim 2, wherein The base material is a sheet-shaped rectangle, and the thickness of the base material is 3 μm to 8 μm.

7. The negative electrode sheet according to claim 1, wherein The thickness of the metal layer and the anticorrosion layer is the same, and the thickness of the metal layer is 1 μm to 30 μm.

8. The negative electrode plate of claim 1, wherein, The thickness of the composite current collector is 5 μm to 50 μm.

9. A solid-state battery, characterized by, The solid-state electrolyte layer includes any one of a sulfide solid-state electrolyte layer and a halide solid-state electrolyte layer or a laminate of both.

10. The solid-state battery of claim 9, wherein, The solid-state electrolyte layer includes any one of a sulfide solid-state electrolyte layer and a halide solid-state electrolyte layer or a laminate of both.

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