Solid-state battery and electric device

Abstract

A solid-state battery comprises a positive electrode sheet (1), a first solid-state electrolyte layer (2), and a negative electrode sheet (3). The positive electrode sheet (1) comprises a positive electrode current collector (11) and a positive electrode active material layer (12) arranged on the positive electrode current collector (11). The negative electrode sheet (3) comprises a negative electrode current collector (31) and a negative electrode active material layer (32) arranged on the negative electrode current collector (31), wherein the positive electrode active material layer (12), the first solid-state electrolyte layer (2) and the negative electrode active material layer (32) have the same length, and the positive electrode active material layer (12), the first solid-state electrolyte layer (2) and the negative electrode active material layer (32) have the same width. The positive electrode active material layer (12) and / or the negative electrode active material layer (32) each comprise / comprises a middle portion (51) and thinned portions (52) arranged in the circumferential direction of the middle portion (51), wherein the thickness of the thinned portions (52) is less than the thickness of the middle portion (51), and a surface of each thinned portion (52) is covered with a second solid-state electrolyte layer (4).

Description

Solid-state battery and electric device

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411392826.7, filed on September 30, 2024, and entitled "Solid-state battery and electric device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of battery manufacturing, in particular to a solid-state battery and an electric device. BACKGROUND

[0004] The all-solid-state battery has attracted widespread attention in the industry due to its non-flammable characteristics and the application of high specific capacity negative electrodes, which is beneficial to improving the energy density of the battery.

[0005] In the manufacturing process of traditional liquid lithium ion batteries, in order to meet the process precision tolerance requirements of the lamination / winding process and avoid the risk of edge misregistration short circuit, the design concept of negative overhang positive is adopted in the battery design, that is, the size of the negative electrode coating is wider than that of the positive electrode coating in the four directions, and there is a so-called overhang area.

[0006] However, in order to form a close accumulation and contact between solid particles in the all-solid-state battery, the all-solid-state battery generally includes a high-pressure forming process in the preparation process, and is often used under restrained conditions. The design of overhang will cause the edge collapse and material falling of the electrode sheet of the all-solid-state battery during the high-pressure forming and use process, thereby increasing the risk of short circuit of the all-solid-state battery. SUMMARY

[0007] The technical problem to be solved by the present disclosure is to provide a solid-state battery and an electric device to solve the problems of edge collapse and material falling of the electrode sheet, and increase the risk of short circuit of the solid-state battery.

[0008] In order to solve the above problems, the present disclosure is realized by the following technical scheme:

[0009] The present disclosure provides a solid-state battery, comprising a positive electrode sheet, a first solid-state electrolyte layer and a negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on the positive electrode current collector, and the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on the negative electrode current collector.

[0010] The length of the positive electrode active material layer, the first solid-state electrolyte layer and the negative electrode active material layer is the same, and the width of the positive electrode active material layer, the first solid-state electrolyte layer and the negative electrode active material layer is the same.

[0011] The positive active material layer and / or the negative active material layer includes an intermediate portion and a thinned portion disposed along the circumference of the intermediate portion, the thickness of the thinned portion being less than the thickness of the intermediate portion, the surface of the thinned portion being covered with a second solid electrolyte layer.

[0012] Further, the number of the thinned portions is a plurality, and the plurality of the thinned portions are disposed around the intermediate portion.

[0013] Further, in the solid-state battery, from the side of the thinned portion close to the intermediate portion to the side away from the intermediate portion, the thickness of the thinned portion decreases, and the thickness of the second solid electrolyte layer increases.

[0014] Further, in the solid-state battery, for any point in the thinned portion, the sum of the thickness of the thinned portion and the thickness of the second electrolyte layer is equal to the thickness of the intermediate portion.

[0015] Further, in the solid-state battery, the thickness of the first solid electrolyte layer is 5um-800um.

[0016] Further, in the solid-state battery, the thickness of the thinned portion away from the intermediate portion is 0-50% of the thickness of the intermediate portion.

[0017] Further, in the solid-state battery, the width of the thinned portion is 0.1mm-40mm.

[0018] Further, in the solid-state battery, the elastic modulus E1 of the active material layer of the electrode sheet having the thinned portion in the positive electrode sheet and the negative electrode sheet, and the modulus E2 of the second solid electrolyte layer covering the thinned portion satisfy E1 / E2>5, and the porosity P1 of the electrode sheet having the thinned portion and the porosity P2 of the second solid electrolyte layer satisfy P2

[0019] Further, in the solid-state battery, the electronic conductivity σe4 of the second electrolyte layer and the electronic conductivity σe2 of the first electrolyte layer satisfy σe4≤σe2<10 -8 S / cm.

[0020] Further, in the solid-state battery, the first solid electrolyte layer includes a first solid electrolyte, and the second solid electrolyte layer includes a second solid electrolyte, the first solid electrolyte and the second solid electrolyte are independently selected from one or more of oxide solid electrolyte, sulfide solid electrolyte, and halide solid electrolyte.

[0021] Further, in the solid-state battery, the oxide solid-state electrolyte is selected from one or more of Li7La3Zr2O 12 10 Al(Ge,Si)2(PO4)7, the sulfide solid-state electrolyte is selected from one or more of Li3PS4, Li 10 GeP2S 12 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 6-x PS 5-x Cl 1+x 11 Li4PS4I, Li7P2S8I, and the halide solid-state electrolyte is selected from one or more of Li3InCl6, Li2ZrO4, Li3YCl6.

[0022] The present disclosure also provides a power-using device, which comprises the above-mentioned solid-state battery as a power supply of the power-using device.

[0023] Compared with the prior art, the present disclosure has the following advantages:

[0024] In the present disclosure, the provided solid-state battery comprises a positive electrode sheet, a first solid-state electrolyte layer, and a negative electrode sheet, the positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer arranged on the positive electrode current collector, the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer arranged on the negative electrode current collector, the lengths and widths of the positive electrode active material layer, the first solid-state electrolyte layer, and the negative electrode active material layer are the same; the positive electrode active material layer and / or the negative electrode active material layer comprises an intermediate part and a thinned part arranged along the circumference of the intermediate part, the thickness of the thinned part is less than the thickness of the intermediate part, and the surface of the thinned part is covered with a second solid-state electrolyte layer, wherein arranging the positive electrode sheet, the first solid-state electrolyte layer, and the negative electrode sheet with the same lengths and widths of the active material layers makes the edges of the battery flush and prevents the battery from collapsing due to the high-pressure forming process; at the same time, the positive electrode active material layer and / or the negative electrode active material layer has a thinned part with a thickness less than that of the intermediate part, and the surface of the thinned part is covered with a second solid-state electrolyte layer, so that the thinned part forms a thicker electronic insulation layer, reducing the risk of edge short circuit, and without additional introduction of electrochemically inactive inert ingredients, the battery design has higher energy density and rate performance; therefore, the solid-state battery provided by the present disclosure can effectively improve the problems of edge collapse, material falling, short circuit, and the like of the existing solid-state battery.

[0025] ​​​​It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory and are not restrictive of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0026] FIG. 1 is a structural schematic diagram of a solid-state battery according to an embodiment of the present disclosure.

[0027] Reference signs: 1 - positive electrode sheet, 11 - positive electrode current collector, 12 - positive electrode active material layer, 2 - first solid-state electrolyte layer, 3 - negative electrode sheet, 31 - negative electrode current collector, 32 - negative electrode active material layer, 4 - second solid-state electrolyte layer, 51 - intermediate portion, 52 - thinned portion. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described in detail below with reference to the drawings and specific embodiments.

[0029] In the prior art, in order to form a close packing and contact between solid particles, full solid-state batteries generally include a high-pressure forming process in the preparation process, and are often used under constrained conditions. If the overhang design in the traditional battery manufacturing process is still used, it will increase the risk of edge collapse, material falling off, and short circuit of the solid-state battery during high-pressure forming and use.

[0030] In order to solve the above problems, the present disclosure provides a solid-state battery, as shown in FIG. 1, which includes a positive electrode sheet 1, a first solid-state electrolyte layer 2, and a negative electrode sheet 3. The positive electrode sheet 1 includes a positive electrode current collector 11 and a positive electrode active material layer 12 disposed on the positive electrode current collector 11. The negative electrode sheet 3 includes a negative electrode current collector 31 and a negative electrode active material layer 32 disposed on the negative electrode current collector 31. The lengths of the positive electrode active material layer 12, the first solid-state electrolyte layer 2, and the negative electrode active material layer 32 are the same. The widths of the positive electrode active material layer 12, the first solid-state electrolyte layer 2, and the negative electrode active material layer 32 are the same. The positive electrode active material layer 12 and / or the negative electrode active material layer 32 includes an intermediate portion 51 and a thinned portion 52 disposed along the circumference of the intermediate portion 51. The thickness of the thinned portion 52 is less than the thickness of the intermediate portion 51. The surface of the thinned portion 52 is covered with a second solid-state electrolyte layer 4.

[0031] Optionally, in the embodiments of the present application, the number of the thinning portions 52 is multiple, and the multiple thinning portions 52 are arranged around the middle portion 51. For example, in the embodiments of the present application, the number of the thinning portions 52 can be four, and the four thinning portions 52 are distributed around the middle portion 51. In addition, the number of the thinning portions 52 can also be two, and the two thinning portions 52 are symmetrically distributed on the outer periphery of the middle portion 51, for example, the two thinning portions 52 can be respectively located on the left side and the right side of the middle portion 51, or the two thinning portions 52 can be respectively located on the upper side and the lower side of the middle portion 51, and the like. The specific arrangement mode of the thinning portion 52 and the middle portion 51 is not limited in the embodiments of the present application.

[0032] The solid-state battery shown in FIG. 1 includes two parallel battery cells, but is only a schematic diagram, and the actual number of cells can be any number as long as the battery structure exhibits this feature, and the embodiments of the present application do not limit this.

[0033] The length and width of the positive active material layer, the first solid-state electrolyte layer and the negative active material layer are arranged to be the same, that is, the positive electrode tab, the first solid-state electrolyte layer and the negative electrode tab have the same edge size, so that the edges of the battery are flush and will not collapse due to the high-pressure forming process; as shown in FIG. 1, the size of the positive electrode tab, the size of the first solid-state electrolyte layer and the size of the negative electrode tab satisfy: W1=W2=W3; wherein W1 is the length of the positive active material layer, W2 is the length of the first solid-state electrolyte layer, and W3 is the length of the negative active material layer, or W1 is the width of the positive active material layer, W2 is the width of the first solid-state electrolyte layer, and W3 is the width of the negative active material layer. When measuring, the size error caused by measurement or process conditions can be ignored.

[0034] The positive active material layer and / or the negative active material layer includes a middle portion and a thinning portion arranged around the middle portion, the thickness of the thinning portion is less than the thickness of the middle portion, and the surface of the thinning portion is covered with a second solid-state electrolyte layer, so that the thinning portion has a thicker electronic insulation layer, reducing the risk of edge short circuit, and without additional introduction of electrochemically inactive inert components, so that the battery design has higher energy density and rate performance.

[0035] Therefore, by using the solid-state battery provided by the present application, the problems of edge collapse, material falling, short circuit and the like of the existing solid-state battery can be effectively improved.

[0036] Optionally, in an embodiment, the positive active material layer and the negative active material layer are both thinning active material layers, that is, there are thinning portions at the edges, so that the thickness variation curve of the thinning portion between the positive electrode tab and the negative electrode tab is more adaptive, and the ratio of the reversible capacity of the negative electrode discharge to the positive electrode discharge (N / P) at the edge can be satisfied.

[0037] In this embodiment, as shown in FIG. 1, the positive active material layer 12 is composed of a positive electrode thinning portion 152 and a positive electrode intermediate portion 151, and the negative active material layer 32 is composed of a negative electrode thinning portion 352 and a negative electrode intermediate portion 351.

[0038] Optionally, in an embodiment, the thickness of the thinning portion decreases from the side close to the intermediate portion to the side away from the intermediate portion, and the thickness of the second solid-state electrolyte layer increases, so that the outside of the thinning portion has a thicker electronic insulation layer, further reducing the risk of edge short circuit.

[0039] Optionally, in an embodiment, for any point in the thinning portion, the sum of the thickness of the thinning portion and the thickness of the second solid-state electrolyte layer is equal to 95% to 105% of the thickness of the intermediate portion, so that the edge and the intermediate thickness do not deviate too much during the forming and testing of the battery, maintaining the consistency of the thickness, and further enabling the thinning portion to be in close contact with the first electrolyte layer, avoiding the situation of edge collapse and material falling during high-pressure forming and use.

[0040] Optionally, in an embodiment, for any point in the thinning portion, the sum of the thickness of the thinning portion and the thickness of the second solid-state electrolyte layer is equal to the thickness of the intermediate portion, so that the edge and the intermediate thickness are consistent during the forming and testing of the battery, and the thinning portion can be in closer contact with the first electrolyte layer, avoiding the situation of edge collapse and material falling during high-pressure forming and use.

[0041] This embodiment specifically includes the following three cases:

[0042] Case one, the negative active material layer does not include a thinning portion, and the positive active material layer includes an intermediate portion and a thinning portion arranged around the intermediate portion, the thickness of the thinning portion is less than the thickness of the intermediate portion, the surface of the thinning portion is covered with a second solid-state electrolyte layer, and for any point in the thinning portion, the sum of the thickness of the thinning portion and the thickness of the second solid-state electrolyte layer is equal to the thickness of the intermediate portion of the positive active material layer.

[0043] In this case one, by covering the surface of the thinning portion of the positive active material layer with a second solid-state electrolyte layer, a thicker electronic insulation layer is formed in the thinning portion, reducing the risk of edge short circuit.

[0044] Case two, the negative active material layer does not include a thinning portion, and the positive active material layer includes an intermediate portion and a thinning portion arranged around the intermediate portion, the thickness of the thinning portion is less than the thickness of the intermediate portion, the surface of the thinning portion is covered with a second solid-state electrolyte layer, and for any point in the thinning portion, the sum of the thickness of the thinning portion and the thickness of the second solid-state electrolyte layer is equal to the thickness of the intermediate portion of the positive active material layer.

[0045] In this case two, by covering the surface of the thinned portion of the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0046] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0047] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0048] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0049] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0050] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit.

[0051] In this case three, by covering the surface of the thinned portion of the positive active material layer and the negative active material layer with a second solid-state electrolyte layer, the thinned portion forms a thicker electron insulating layer, reducing the risk of edge short circuit. 1AThe thickness L1 of its middle part satisfies 0 ≤ H 1A / L1≤50%, the outermost thickness H of the thinned portion of the negative electrode active material layer 3A The thickness L3 of its middle part satisfies 0 ≤ H 3A / L3≤50%.

[0052] Optionally, in one embodiment, the width of the thinned portion is 0.1 mm to 40 mm, where the width is the distance between the side of the thinned portion away from the middle portion and the middle portion. When the width of the thinned portion is within the above range, edge short circuits can be effectively limited while also ensuring battery energy density. Optionally, the width of the thinned portion can be one or any two of the following: 0.1 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 20 mm, 30 mm, and 40 mm.

[0053] In this embodiment of the disclosure, the second solid electrolyte layer is used to offset the height difference between the thinned portion and the middle portion, while making the thinned portion form a thicker electronic insulating layer, reducing the risk of edge short circuits.

[0054] Optionally, in one embodiment, when the elastic modulus E1 of the active material layer and the modulus E2 of the second solid electrolyte layer covering it in the thinned electrode satisfy E1 / E2>5, the porosity P1 of the thinned electrode and the porosity P2 of the second solid electrolyte layer satisfy P2<P1<12%.

[0055] When E1 / E2 < 5, the porosity of both can be disregarded; alternatively, P2 < P1 < 12% results in greater consistency in thickness between the middle and edge regions of the battery.

[0056] Preferably, in one embodiment, the elastic modulus E of the positive electrode active material layer in the thinned positive electrode sheet is... 1p and the modulus E of the second solid electrolyte layer covering it 2p The space satisfies E 1p / E 2p When the porosity P of the thinned positive electrode active material layer is greater than 5, the porosity P of the thinned positive electrode sheet is greater than 5. 1p The porosity P of the second solid electrolyte layer 2p Satisfy P 2p <P 1p The deformation rate is less than 12%, ensuring that the deformation rates of the compacted, thinned positive electrode sheet and the second solid electrolyte layer remain similar, thus maintaining the consistency of the overall battery thickness. Since the positive electrode sheet is relatively thick in solid-state batteries, its parameters have a significant impact on battery performance. Meeting the above range for both the positive electrode sheet and the second solid electrolyte layer contributes more to battery performance.

[0057] Under the modulus relationship, the deformation amount of the electrolyte material in the second solid electrolyte layer is much larger than that of the electrode sheet during the restraint test, and the second solid electrolyte layer needs to have a lower porosity to ensure that the second solid electrolyte layer will not produce excessive deformation when being pressed, so as to avoid a large deviation between the deformation amount of the second solid electrolyte layer and the active material layer on the electrode sheet, resulting in a mismatch in thickness between the middle and edge regions of the battery, so that when the positive active material layer has a thinned part, the thickness relationship between the second solid electrolyte layer and the positive active material layer is maintained within the range of 95%≤(H 1a +H 4a ) / L1≤105%, and when the negative active material layer has a thinned part, the thickness relationship between the second solid electrolyte layer and the negative active material layer is maintained within the range of 95%≤(H 3a +H 4b ) / L3≤105%; wherein H 1a , H 4a are the thicknesses of the thinned part at any point in the positive active material layer and the thickness of the second solid electrolyte layer, respectively, and H 3a , H 4b are the thicknesses of the thinned part at any point in the negative active material layer and the thickness of the second solid electrolyte layer, respectively.

[0058] Optionally, in an embodiment, the electronic conductivity σ e4 of the second electrolyte layer and the electronic conductivity σ e2 of the first electrolyte layer satisfy σ e4 ≤σ e2 <10 -8 S / cm, which can effectively ensure good electronic insulation performance at the edge.

[0059] In the embodiments of the present disclosure, the first solid electrolyte layer comprises a first solid electrolyte, and the second solid electrolyte layer comprises a second solid electrolyte. Optionally, in an embodiment, the first solid electrolyte and the second solid electrolyte are independently selected from one or more of a phosphate-based solid electrolyte, an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.

[0060] In the embodiments of the present disclosure, the contact impedance between the first electrolyte layer and the second electrolyte layer is small, thereby reducing the overall impedance of the battery. Optionally, the first solid electrolyte and the second solid electrolyte are the same, and the contact impedance is smaller, thereby more significantly reducing the overall impedance of the battery.

[0061] Optionally, in a specific embodiment, the phosphate-based solid electrolyte is selected from lithium aluminum titanium phosphate (LATP), and the oxide solid electrolyte is selected from Li7La3Zr2O 12 , Li 10one or more of Al(Ge, Si)2(PO4)7, sulfide solid-state electrolytes selected from Li3PS4, Li 10 GeP2S 12 , Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 , Li 6-x PS 5-x Cl 1+x , Li7P3S 11 , Li4PS4I, Li7P2S8I, halide solid-state electrolytes selected from one or more of Li3InCl6, Li2ZrO4, Li3YCl6.

[0062] When the LATP oxide electrolyte is used, the modulus and the positive electrode modulus are close, the edge electrolyte area porosity and the positive electrode porosity ratio do not need to be specially controlled, the modulus is relatively high, the structure is more stable, and the cycle stability is improved.

[0063] In the embodiment of the present disclosure, the positive electrode active material layer comprises a positive electrode active material, a third solid-state electrolyte, a conductive agent, and a polymer binder, wherein the proportion of the positive electrode active material is 40-94wt%, the proportion of the third solid-state electrolyte is 5-60wt%, the proportion of the conductive agent is 0-10%, and the proportion of the binder is 0.1-10%.

[0064] The positive electrode active material comprises one or more of olivine, layered oxide, spinel, sulfur positive electrode, and sulfide positive electrode material, wherein the olivine is LiFePO4, the layered oxide is lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), or LiCoO2, the spinel is LiMn2O4, Li4Ti5O 12 , sulfur positive electrode, and sulfide positive electrode are S8, FeS2, CuS, etc.; the conductive agent is a commonly used conductive agent for positive electrodes, such as acetylene black, carbon nanotubes, carbon fibers, carbon black, etc.; the third solid-state electrolyte is selected from one or more of oxide solid-state electrolyte, sulfide solid-state electrolyte, and halide solid-state electrolyte; and the polymer binder can be one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), polyacrylate, polyacrylic acid (PAA), alkyl cellulose, and polyethylene oxide (PEO), and hydrogenated nitrile rubber.

[0065] In some embodiments, the positive electrode sheet is prepared as follows: the components used to prepare the positive electrode sheet, such as the positive electrode active material, the binder, and any other components described above, are dispersed in a solvent such as N-methyl pyrrolidone to form a positive electrode slurry; the positive electrode slurry is coated on both sides of a positive current collector such as an aluminum foil; after baking, rolling, sheet cutting, and other processes, the positive electrode sheet is obtained.

[0066] In the embodiments of the present disclosure, the negative electrode active material layer contains a negative electrode active material, which can be a negative electrode active material used in a battery and capable of absorbing and releasing metal ions (such as lithium ions), for example, selected from metal negative electrode materials or non-metal negative electrode materials; the metal negative electrode material is preferably lithium metal or lithium metal alloy; the non-metal negative electrode material is preferably any one or a combination of at least two of hard carbon, soft carbon, graphite, silicon monoxide, silicon-carbon composite, Si, and silicon alloy.

[0067] Optionally, in an embodiment, when the negative electrode active material is selected from a non-metal negative electrode material, the negative electrode sheet further includes a conductive agent, a binder, and a fourth solid electrolyte, the conductive agent is selected from at least one of acetylene black, Super P, Super S, graphene, carbon fiber, carbon nanotube, and Ketjen black, the binder is selected from at least one of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, polyacrylonitrile, polypropylene carbonate, butadiene rubber, nitrile rubber, sodium carboxymethyl cellulose, polyethylene oxide, and ethylene oxide-propylene oxide copolymer, and the fourth solid electrolyte is selected from one or more of oxide solid electrolyte, sulfide solid electrolyte, and halide solid electrolyte.

[0068] Optionally, in an embodiment, the negative electrode active material layer further includes a plasticizer, and the plasticizer is selected from at least one of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol diethyl ether, tetrapropylene glycol diethyl ether, 1,3-dioxolane, 1,4-dioxane, propylene carbonate, ethylene carbonate, diethyl carbonate, or dimethyl carbonate, butanedinitrile, and hexanedinitrile.

[0069] In some embodiments, the negative electrode sheet is prepared as follows: the components used to prepare the negative electrode sheet, such as the negative electrode active material, the binder, and the conductive agent described above, are dispersed in a solvent such as deionized water to form a negative electrode slurry; the negative electrode slurry is coated on both sides of a negative current collector such as a copper foil; after baking, rolling, sheet cutting, and other processes, the negative electrode sheet is obtained.

[0070] In actual application, the negative electrode sheet, the polymer electrolyte film and the positive electrode sheet are stacked in sequence to obtain a roll core, two-sealing and sorting to obtain the above-mentioned solid-state battery.

[0071] In the above-mentioned two-sealing process, isostatic pressing can be used, the forming pressure is 400-600 MPa, and the temperature is 80-150°C. When the forming pressure is lower, the structural strength is affected, and the performance of the prepared solid-state battery is slightly poor.

[0072] The present disclosure also provides a power-using device, which comprises the above-mentioned solid-state battery as a power supply of the power-using device.

[0073] For the above-mentioned solid-state battery embodiment and power-using device embodiment, the polymer electrolyte is included, and the same technical effects can be achieved. To avoid repetition, details are not described here, and the relevant part can be referred to the part of the polymer electrolyte embodiment.

[0074] In order to make the purpose, technical scheme and beneficial effects of the present disclosure clearer, the present disclosure will be further described in combination with embodiments. It should be understood that these embodiments are only used to illustrate the present disclosure and not to limit the scope of the present disclosure.

[0075] The present disclosure will be described in detail below through embodiments.

[0076] Test method:

[0077] (1) Thinning part size test: a focused ion beam (FIB) is used to cut the edge section of the electrode sheet, SEM is used to observe the thickness of the electrode sheet coating area, the position with a thickness of 95% of the center thickness of the electrode sheet is the thinning part, and the distance from the edge of the electrode sheet is the thinning part width.

[0078] (2) Test method of elastic modulus: test by nanoindentation instrument, nano-diamond indenter applies load to the surface of the electrode sheet, the load-displacement curve is recorded by computer, and the elastic modulus information of the corresponding material layer is output.

[0079] (3) Test method of porosity: the material layer in the electrode sheet is cut into a circular sheet with a thickness of L and a diameter of D, and the mass M of the circular sheet is weighed, combined with the weighted average density p of all materials in the material layer 理论 , according to the porosity P=(1-4M / ρ 理论 πD 2 L)×100% to calculate.

[0080] (4) Electronic conductivity test method: 100 mg of powder on the corresponding electrolyte layer was weighed in an argon atmosphere glove box, and an electrolyte sheet was pressed at 120 MPa using a mold with a diameter D = 10 mm. The thickness L of the electrolyte sheet was recorded. An aluminum foil disc coated with carbon was added to both sides of the electrolyte sheet, and an Al|solid-state electrolyte|Al battery was assembled by applying a pressure of 380 MPa. The direct current internal resistance R was tested and calculated by direct current polarization of an electrochemical workstation (VMP-300). The electronic conductivity σ e = 4L / πRD 2 was calculated.

[0081] (5) First cycle capacity test: The prepared battery was connected to a charge-discharge test cabinet under the constraint of a 20 megapascal pressure tool. The battery was charged at a rate of 0.1C to 100% SOC, and the charge capacity was recorded. After standing for 5 min, the battery was discharged at a rate of 0.1C to 0 SOC state, and the discharge capacity was recorded as the first cycle capacity.

[0082] (6) First cycle efficiency test: The percentage of discharge capacity to charge capacity in the above process was calculated, and was recorded as the first cycle efficiency.

[0083] (7) Cycle performance test: The battery was subjected to charge-discharge cycling at a rate of 0.33C until the discharge capacity of the battery decreased to 80% of the initial discharge capacity. The number of cycles at that time was recorded as the cycle performance.

[0084] Example 1

[0085] (1) Preparation of positive electrode sheet

[0086] The positive electrode active material single crystal LiNi 0.9 Co 0.05 Mn 0.05 O2, solid-state electrolyte Li6PS5Cl1, binder hydrogenated nitrile rubber (HNBR), and conductive agent Super P were mixed in a mass ratio of 80:2:1:1 in N,N-dimethylformamide, then the slurry was coated on an aluminum current collector using a doctor blade, and the slurry thickness was controlled to decrease in the area with an edge width of 10 mm as a thinning part, and the outermost slurry thickness was 20% of the center area slurry thickness. Then, drying was performed at 60°C for 1 h and at 80°C for 3 h to obtain a positive electrode sheet, wherein the D50 of the positive electrode active material was 3 um, and the D50 of the solid-state electrolyte was 1.5 um.

[0087] (2) Preparation of the first solid-state electrolyte layer

[0088] The solid-state electrolyte Li6PS5Cl1 and the binder HNBR were mixed in a mass ratio of 99:1 to prepare the first solid-state electrolyte layer, wherein the particle size of the solid-state electrolyte was 3 um.

[0089] (3) Preparation of the negative electrode tab

[0090] The negative electrode tab with the same size as the positive electrode tab was prepared by mixing pure Si material, binder hydrogenated nitrile rubber (HNBR) and conductive agent Super P at a mass ratio of 85:10:5. The slurry thickness in the area with an edge width of 10 mm was controlled to decrease as a thinning part, and the slurry thickness of the outermost side was 20% of the slurry thickness of the central area.

[0091] (4) Preparation of the second solid electrolyte layer

[0092] The solid-state electrolyte Li6PS5Cl 0.5 Br 0.5 , binder PVDF-HFP were mixed at a mass ratio of 90:10, and then coated on the thinning part of the positive electrode tab and the negative electrode tab respectively until the surface was flush with the slurry of the central area, to prepare the second solid electrolyte layer.

[0093] (5) Preparation of the solid-state battery

[0094] In the argon-filled glove box, the positive electrode tab, the first solid electrolyte layer and the negative electrode tab were aligned and assembled in order, and then isostatic pressing was performed under the conditions of a pressure of 500 MPa and a temperature of 80°C to prepare the solid-state battery.

[0095] Example 2

[0096] The difference from Example 1 is only that in step (5), the pressure of isostatic pressing is adjusted to 400 MPa and the temperature is 80°C.

[0097] Example 3

[0098] The difference from Example 1 is only that in step (5), the pressure of isostatic pressing is adjusted to 600 MPa and the temperature is 80°C.

[0099] Example 4

[0100] The difference from Example 1 is only that in step (5), the pressure of isostatic pressing is adjusted to 100 MPa and the temperature is 25°C.

[0101] Example 5

[0102] The difference from Example 1 is only that in step (4), the solid-state electrolyte is adjusted to be of the LATP type, specifically Li 1.3 Al 0.3 Ti 1.7 (PO4)3.

[0103] Example 6

[0104] The difference from Example 5 is only that, in step (5), the pressure of isostatic pressing is adjusted to 400 MPa and the temperature is 80°C.

[0105] Example 7

[0106] The difference from Example 1 is only that, in step (4), the solid electrolyte is adjusted to Li7P3S 11 .

[0107] Example 8

[0108] The difference from Example 1 is only that, in steps (1) and (3), the thickness of the slurry is controlled to decrease as a thinning portion in a region with a width of 5 mm at the edge.

[0109] Example 9

[0110] The difference from Example 1 is only that, in steps (1) and (3), the thickness of the slurry is controlled to decrease as a thinning portion in a region with a width of 0.1 mm at the edge.

[0111] Example 10

[0112] The difference from Example 1 is only that, in steps (1) and (3), the thickness of the slurry is controlled to decrease as a thinning portion in a region with a width of 40 mm at the edge.

[0113] Example 11

[0114] The difference from Example 1 is only that, in steps (1) and (3), the thickness of the slurry at the outermost side of the thinning portion is controlled to be 40% of the thickness of the slurry at the center region.

[0115] Example 12

[0116] Example 11 differs from Example 1 in that, in steps (1) and (3), the thickness of the slurry at the outermost side of the thinning portion is controlled to be 50% of the thickness of the slurry at the center region.

[0117] Example 13

[0118] Example 13 differs from Example 1 in that, in steps (1) and (3), the thickness of the slurry at the outermost side of the thinning portion is controlled to be 70% of the thickness of the slurry at the center region.

[0119] Example 14

[0120] Example 14 differs from Example 1 in that, in steps (1) and (2), the particle size D50 of the solid is adjusted to 5 um.

[0121] Comparative Example 1

[0122] Comparative Example 1 differs from Example 1 in that step (4) is omitted.

[0123] Comparative Example 2

[0124] Comparative Example 1 and Example 1 differ in that step (4) is omitted, and no thinning portion is provided in steps (1) and (3).

[0125] The components and parameters of the solid-state battery in each example and comparative example are shown in Table 1.

[0126] The solid-state batteries prepared in each example and comparative example were subjected to thinning portion size testing, elastic modulus testing, porosity testing, and electronic conductivity testing, and the test data are shown in Table 1.

[0127] The solid-state batteries prepared in each example and comparative example were subjected to first cycle capacity testing, first cycle efficiency, and cycle performance testing, and the test data are shown in Table 2.

[0128] Table 1

[0129] Table 2

[0130] According to the above test data, the active material layer is thinned at the edges of the positive electrode tab and the negative electrode tab, and the solid electrolyte layer is covered, which can form a thicker electronic insulation layer between the positive electrode tab and the negative electrode tab, reduce the risk of edge short circuit, and also obtain better cycle performance.

[0131] Although the preferred embodiments of the present disclosure have been described, those skilled in the art can make further changes and modifications to these embodiments once they understand the basic inventive concept. Therefore, the claims are intended to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present disclosure.

[0132] The above provides a kind of solid-state battery and power utilization equipment provided by the present disclosure, has carried out detailed introduction, specific example is applied in this paper to the principle and implementation mode of the present disclosure are described, the above example is only for helping to understand the method of the present disclosure and its core idea;For the person skilled in the art, according to the idea of the present disclosure, there will be changes in specific implementation mode and application range, and the above description of the specification should not be understood as the limitation of the present disclosure.

Claims

1. A solid-state battery, wherein, The positive electrode sheet (1) includes a positive electrode current collector (11) and a positive electrode active material layer (12) provided on the positive electrode current collector (11), and the negative electrode sheet (3) includes a negative electrode current collector (31) and a negative electrode active material layer (32) provided on the negative electrode current collector (31); The positive electrode active material layer (12), the first solid-state electrolyte layer (2), and the negative electrode active material layer (32) have the same length, and the positive electrode active material layer (12), the first solid-state electrolyte layer (2), and the negative electrode active material layer (32) have the same width; The positive electrode active material layer (12) and / or the negative electrode active material layer (32) include an intermediate portion (51) and a thinned portion (52) provided along the circumference of the intermediate portion (51), the thickness of the thinned portion (52) is less than the thickness of the intermediate portion (51), and the surface of the thinned portion (52) is covered with a second solid-state electrolyte layer (4).

2. The solid-state battery of claim 1, wherein, The number of the thinned portions (52) is multiple, and the multiple thinned portions (52) are provided around the intermediate portion (51).

3. The solid-state battery of claim 1, wherein, From the side close to the intermediate portion (51) to the side away from the intermediate portion (51), the thickness of the thinned portion (52) decreases, and the thickness of the second solid-state electrolyte layer (4) increases.

4. The solid-state battery of any one of claims 1-3, wherein, For any point in the thinned portion (52), the sum of the thickness of the thinned portion (52) and the thickness of the second solid-state electrolyte layer (4) is equal to 95% to 105% of the thickness of the intermediate portion (51).

5. The solid-state battery of claim 4, wherein, For any point in the thinned portion (52), the sum of the thickness of the thinned portion (52) and the thickness of the second solid-state electrolyte layer (4) is equal to the thickness of the intermediate portion (51).

6. The solid-state battery according to any one of claims 1 to 5, wherein The thickness of the first solid-state electrolyte layer (2) is 5 um to 800 um.

7. The solid-state battery according to any one of claims 1 to 6, wherein The thickness of the thinned portion (52) away from the intermediate portion (51) is 0 to 50% of the thickness of the intermediate portion (51).

8. The solid-state battery according to any one of claims 1 to 7, wherein The width of the thinned portion (52) is 0.1 mm to 40 mm.

9. The solid-state battery according to any one of claims 1 to 8, wherein When the elastic modulus E1 of the active material layer of the sheet having the thinned portion (52) in the positive electrode sheet (1) and the negative electrode sheet (3) and the elastic modulus E2 of the second solid-state electrolyte layer (4) covering the thinned portion (52) satisfy E1 / E2>5, the porosity P1 of the sheet having the thinned portion (52) and the porosity P2 of the second solid-state electrolyte layer (4) satisfy P2 10. The solid-state battery according to any one of claims 1 to 9, wherein the second electrolyte layer electronic conductivity σ e4 and the first electrolyte layer electronic conductivity σ e2 satisfies σ e4 ≤ σ e2 < 10 -8 S / cm.

11. The solid-state battery of claim 10, wherein, The first solid-state electrolyte layer (2) includes a first solid-state electrolyte, and the second solid-state electrolyte layer (4) includes a second solid-state electrolyte, the first solid-state electrolyte and the second solid-state electrolyte are independently selected from one or more of oxide solid-state electrolytes, sulfide solid-state electrolytes, and halide solid-state electrolytes.

12. The solid-state battery of claim 11, wherein, The oxide solid electrolyte is selected from Li7La3Zr2O 12 Li 10 One or more of Al(Ge,Si)2(PO4)7, wherein the sulfide solid electrolyte is selected from Li3PS4, Li 10 GeP2S 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 6-x PS 5-x Cl 1+x Li7P3S 11 The solid-state electrolyte is selected from one or more of Li4PS4I and Li7P2S8I, and the halide solid electrolyte is selected from one or more of Li3InCl6, Li2ZrO4, and Li3YCl6.

13. An electrical device comprising the solid-state battery according to any one of claims 1 to 12 as a power supply for the electrical device.

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