Solid-state battery cell and method of manufacturing the same, battery device, and power using device

Abstract

The application provides a solid-state battery monomer, a preparation method of the solid-state battery monomer, a battery device and a power utilization device. The solid-state battery monomer comprises a positive electrode sheet, a negative electrode sheet and a solid electrolyte; the solid electrolyte comprises a sulfide; the positive electrode sheet comprises a positive electrode material; a separation layer is arranged between the positive electrode sheet and the sulfide solid electrolyte, and the separation layer comprises a compound Li 3‑n A 1‑ x B x Cl 6‑a‑b Br a F b The cycle performance and fast charging performance of the solid-state battery monomer are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to solid-state battery cells, methods for preparing solid-state battery cells, battery devices, and power-consuming devices. Background Technology

[0002] In recent years, with the increasingly wide range of applications, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. Due to the significant advancements in battery technology, higher requirements have been placed on their cycle stability and fast-charging performance. Summary of the Invention

[0003] This application was made in view of the above-mentioned problems, and its purpose is to provide a solid-state battery cell, a method for preparing a solid-state battery cell, a battery device, and an electrical device. The solid-state battery cell of this application improves the cycle stability and fast-charging performance.

[0004] To achieve the above objectives, a first aspect of this application provides a solid-state battery cell, comprising a positive electrode, a negative electrode, and a solid electrolyte; the solid electrolyte comprises a sulfide; the positive electrode comprises a positive electrode material; a separator layer is provided between the positive electrode and the sulfide solid electrolyte, the separator layer comprising the compound Li. 3-n A 1-x B x Cl 6-a- b Br a F b ;in,

[0005] A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7; 0 ≤ a ≤ 2; 0 < b ≤ 0.25; n = 0 when the valence states of the elements in A and B are equal or when B does not exist; n = x when the valence states of the elements in A and B are not equal.

[0006] Therefore, this application provides a mixture containing the compound Li between the positive electrode and the solid electrolyte. 3-n A 1-x B x Cl 6-a-b Br a F bThe separator layer improves the cycle stability of the battery cells and reduces the impedance of the battery cells, thereby improving the fast charging performance of the battery cells.

[0007] In any embodiment, the thickness of the separator layer is 2%-15% or 4%-8% of the thickness of the solid electrolyte. Therefore, this range of separator layer thickness to solid electrolyte thickness can, on the one hand, effectively suppress side reactions between the positive electrode active material and the solid electrolyte, thereby improving the cycle stability of the battery cell; on the other hand, it reduces the negative impact of increased separator layer thickness on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by increased separator layer thickness on the cycle stability of the battery cell.

[0008] In any embodiment, the thickness of the separator layer is 0.028-0.173 mm, 0.045-0.072 mm, or 0.04-0.15 mm. Therefore, the aforementioned thickness range of the separator layer allows it to effectively separate the positive electrode active material from the solid electrolyte and suppress their side reactions, thereby improving the cycle stability of the battery cell. Furthermore, it reduces the negative impact of increased separator layer thickness on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by increased separator layer thickness on the cycle stability of the battery cell.

[0009] In any embodiment, one or more of the separator layer, the positive electrode material, and the solid electrolyte include one or more characteristic elements selected from Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, In, Ti, Zr, Hf, and Rf.

[0010] In any embodiment, the mass content of the characteristic element in the separator layer is 19%-32% or 21%-30%.

[0011] Therefore, in addition to the characteristic elements of the compound being detectable in the separator layer, the compound may also infiltrate into the cathode material and / or solid electrolyte, thus allowing the characteristic elements to be detected in the cathode material and / or solid electrolyte.

[0012] In any embodiment, the separator layer and / or the positive electrode material comprises halogen.

[0013] In any embodiment, the halogen content in the separator layer is 65%-75% or 67%-74% by mass.

[0014] Therefore, in addition to the halogens of the compound being detectable in the separator layer, the compound may also infiltrate into the cathode material, thus allowing the halogens to be detected in the cathode material.

[0015] In any embodiment, the compound includes Li3YCl4Br 1.9 F 0.1 ,Li3HoCl4Br 1.8 F 0.2 ,Li3HoCl4Br 1.9 F 0.1 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F 0.1 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F 0.1 Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F 0.1 Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 Li 2.6 Y 0.6 Zr 0.4 Cl 4.5 Br 1.4 F 0.1 Li 2.4 Yb 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 Li 2.5 Yb 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 Li 2.5 Er 0.5 Zr 0.5 Cl4.5 Br 1.4 F 0.1 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 One or more of them.

[0016] Therefore, the aforementioned compounds can further suppress the side reactions between the positive electrode active material and the sulfide solid electrolyte, improve the cycle stability of the battery cell, and reduce the impedance of the battery cell, thereby improving the fast charging performance of the battery cell.

[0017] In any embodiment, the volume fraction of the separator layer in the battery cell is 2.74%-20.73%, 4.7%-20.1%, or 4.67%-8.05%. Thus, on the one hand, the separator layer can effectively separate the positive electrode active material from the solid electrolyte and inhibit their reaction, thereby improving the cycle stability of the battery cell; on the other hand, it reduces the negative impact of the increased volume fraction of the separator layer on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by the increased volume fraction of the separator layer on the cycle stability of the battery cell.

[0018] The second aspect of this application provides a method for preparing a solid-state battery cell, which is either method one or method two.

[0019] Method 1 includes the following steps:

[0020] Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The solid electrolyte containing sulfides is dispersed on one side and then subjected to a first cold pressing to obtain a solid electrolyte with a separator layer on one side.

[0021] The negative electrode is placed on the other side of the solid electrolyte, and the positive electrode is placed on the side of the separator away from the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell.

[0022] The second method includes the following steps:

[0023] Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The positive electrode sheet is dispersed on the side that is close to the solid electrolyte, and after a first cold pressing, a positive electrode sheet with a separator layer on one side is obtained;

[0024] The solid electrolyte is placed on the side of the separator layer away from the positive electrode, and the negative electrode is placed on the other side of the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell.

[0025] Wherein, A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7; 0 ≤ a ≤ 2; 0 < b ≤ 0.25; when the valence states of the elements in A and B are equal or B does not exist, n = 0; when the valence states of the elements in A and B are not equal, n = x.

[0026] Therefore, this application provides a mixture containing the compound Li between the positive electrode and the solid electrolyte. 3-n A 1-x B x Cl 6-a-b Br a F b The separator layer improves the cycle stability of the battery cells and reduces the impedance of the battery cells, thereby improving the fast charging performance of the battery cells.

[0027] In any embodiment, the pressure of the first cold press is 250-340 MPa; and / or,

[0028] The first cold pressing time is 10-60 seconds.

[0029] In any embodiment, the pressure of the second cold pressing is 300-650 MPa; and / or,

[0030] The second cold pressing time is 180-360 seconds.

[0031] In any embodiment, the mass ratio of the compound to the solid electrolyte is (10-40):(60-90).

[0032] In any embodiment, the compound includes Li3YCl4Br 1.9 F 0.1 ,Li3HoCl4Br 1.8 F 0.2 ,Li3HoCl4Br 1.9 F 0.1 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F0.1 、 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 、 Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 、 Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 、 Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F[[ID=4Ø]] 0.1 、 Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F 0.1 、 Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br[[ID=6Ø]] 1.4 F 0.1 、 Li 2.6 Y 0.6 Zr 0.4 Cl[[ID=7Ø]] 4.5 Br 1.4 F 0.1 、 Li 2.4 Yb 0.4 Zr[[ID=8Ø]] 0.6 Cl 4.5 Br 1.4 F 0.1 、 Li 2.5 Yb[[ID=9Ø]] 0.5 Zr 0.5 Cl 4.5 Br 1.4 ] F 0.1 、 Li 2.5 Er 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 、 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 one or more of the above.

[0033] A third aspect of this application provides a battery device, including a solid-state battery cell according to the first aspect of this application or a solid-state battery cell prepared by the method of the second aspect of this application.

[0034] The fourth aspect of this application provides an electrical device, including a battery cell of the first aspect of this application or a battery device of the third aspect of this application. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a battery cell according to one embodiment of this application.

[0036] Figure 2 yes Figure 1 An exploded view of a battery cell according to one embodiment of this application is shown.

[0037] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application.

[0038] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0039] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0040] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0043] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery module, battery pack, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0044] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0045] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0046] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0047] [Battery cell]

[0048] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0049] The battery cells can be solid-state batteries.

[0050] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator positioned between the positive and negative electrodes. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0051] One embodiment of this application provides a solid-state battery cell, including a positive electrode, a negative electrode, and a solid electrolyte; the solid electrolyte includes a sulfide; the positive electrode includes a positive electrode material; a separator layer is provided between the positive electrode and the sulfide solid electrolyte, the separator layer including the compound Li. 3-n A 1-x B x Cl 6-a-b Br a F b ;in,

[0052] A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or any range of the above values; 0 ≤ a ≤ 2, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 The range of values ​​1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or any of the above values; 0 < b ≤ 0.25, for example, 0.01, 0.03, 0.05, 0.08, 0.1, 0.11, 0.13, 0.14, 0.15, 0.16, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, or any of the above values; when the valence states of elements in A and B are equal or B does not exist, n = 0; when the valence states of elements in A and B are not equal, n = x.

[0053] In existing solid-state battery cells, the byproducts generated from the reaction between the positive electrode active material and the sulfide-containing solid electrolyte lead to a decrease in the cycle performance of the battery cell, as well as an increase in impedance and a decrease in fast-charging performance. Although there are currently methods to suppress the reaction between the positive electrode active material and the sulfide solid electrolyte by adding compounds, these compounds themselves are prone to reacting with sulfides and have poor stability, which has a significant impact on the cycle performance and fast-charging performance of the battery cell.

[0054] To solve the aforementioned technical problems, the applicant unexpectedly discovered that: this application incorporates a compound Li between the positive electrode and the solid electrolyte. 3-n A 1-x B x Cl 6-a-b Br a F b The separator layer effectively suppresses the side reactions between the positive electrode active material and the sulfide-containing solid electrolyte. Furthermore, the compounds in the separator layer are not prone to reacting with the sulfides in the solid electrolyte and have high stability, which reduces the generation of by-products and improves the cycle stability of the battery cell. In addition, the reduction of by-products lowers the impedance of the battery cell, thereby improving the fast charging performance of the battery cell.

[0055] In some embodiments, the thickness of the separator layer is 2%-15% or 4%-8% of the thickness of the solid electrolyte, for example, 2%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or any combination of the above values. Therefore, the ratio of separator layer thickness to solid electrolyte thickness can effectively suppress side reactions between the positive electrode active material and the solid electrolyte, thereby improving the cycle stability of the battery cell; on the other hand, it reduces the negative impact of increased separator layer thickness on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by increased separator layer thickness on the cycle stability of the battery cell.

[0056] In some embodiments, the thickness of the separator layer is 0.028-0.173 mm, 0.045-0.072 mm, or 0.04-0.15 mm, for example, 0.028 mm, 0.03 mm, 0.04 mm, 0.045 mm, 0.05 mm, 0.055 mm, 0.057 mm, 0.06 mm, 0.062 mm, 0.064 mm, 0.066 mm, 0.07 mm, 0.072 mm, 0.075 mm, 0.077 mm, 0.08 mm, 0.085 mm, 0.09 mm, 0.095 mm, 0.10 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, or any range of the above values. Therefore, the aforementioned thickness range of the separator layer enables it to effectively separate the positive electrode active material from the solid electrolyte and suppress their side reactions, thereby improving the cycle stability of the battery cell. On the other hand, it reduces the negative impact of increased separator layer thickness on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by increased separator layer thickness on the cycle stability of the battery cell.

[0057] In this application, the separator thickness and the separator-to-solid electrolyte thickness ratio are tested using conventional methods in the art. For example, the battery cell is disassembled, the electrode assembly is removed, and the electrode assembly is cut using an ion beam along the arrangement direction of the positive electrode, separator, solid electrolyte, and negative electrode. The separator thickness and solid electrolyte thickness on the cross-section are measured using SEM or FIB-SIMS, and the separator thickness to solid electrolyte thickness ratio is calculated. To make the test results more accurate, the separator thickness and separator-to-solid electrolyte thickness ratio can also be measured at multiple points on the cross-section, and the average value is taken.

[0058] In some embodiments, one or more of the separator layer, the positive electrode material, and the solid electrolyte include one or more characteristic elements selected from Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, In, Ti, Zr, Hf, and Rf.

[0059] In some embodiments, the mass content of the characteristic element in the separator layer is 19%-32% or 21%-30%, for example 19%, 20%, 21%, 21.5%, 22%, 22.16%, 22.28%, 22.5%, 22.7%, 23%, 23.3%, 23.5%, 23.6%, 23.7%, 23.8%, 23.9%, 24%, 24.02%, 24.2%, 24.5%, 24.6%, 24.7%, 2 4.8%, 25%, 25.5%, 26%, 26.5%, 26.6%, 26.7%, 26.8%, 27%, 27.02%, 27.5%, 27.6%, 27.8%, 27.9%, 28%, 28.3%, 28.5%, 28.6%, 28.7%, 28.9%, 29%, 29.1%, 29.2%, 29.5%, 30%, 30.5%, 31%, 31.5%, 32%, or any range of the above values.

[0060] Therefore, in addition to the characteristic elements of the compound being detectable in the separator layer, the compound may also infiltrate into the cathode material and / or solid electrolyte, thus allowing the characteristic elements to be detected in the cathode material and / or solid electrolyte.

[0061] In some embodiments, the separator layer and / or the positive electrode material comprises halogen.

[0062] In some embodiments, the halogen content in the separator layer is 65%-75% or 67%-74% by mass, for example, 65%, 66%, 67%, 67.5%, 67.8%, 67.9%, 68%, 68.5%, 69%, 69.5%, 69.7%, 70%, 70.3%, 70.5%, 70.8%, 71%, 71.5%, 71.8%, 71.9%, 72%, 72.4%, 72.6%, 72.8%, 72.9%, 73%, 73.1%, 73.2%, 73.5%, 73.8%, 74%, 74.5%, 75%, or any range of the above values.

[0063] Therefore, in addition to the halogens of the compound being detectable in the separator layer, the compound may also infiltrate into the cathode material, thus allowing the halogens to be detected in the cathode material.

[0064] In some embodiments, the compound includes Li3YCl4Br1.9 F 0.1 、Li3HoCl4Br 1.8 F 0.2 、Li3HoCl4Br 1.9 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 、Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 、Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F 0.1 、Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.6 Y 0.6 Zr 0.4 Cl 4.5 Br 1.4 F 0.1 、Li 2.4 Yb 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Yb 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Er 0.5 Zr 0.5 Cl 4.5 Br 1.4 F0.1 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 One or more of them.

[0065] Therefore, the aforementioned compounds can further suppress the side reactions between the positive electrode active material and the sulfide solid electrolyte, improve the cycle stability of the battery cell, and reduce the impedance of the battery cell, thereby improving the fast charging performance of the battery cell.

[0066] In this application, the elements and their contents in the separator, positive electrode material, or solid electrolyte are measured using conventional methods in the art. For example, the electrode components in the battery cell are removed, the separator, positive electrode sheet, or solid electrolyte are disassembled, the separator, positive electrode sheet, or solid electrolyte are thoroughly cleaned with DMC (dimethyl carbonate) and dried, the separator material, positive electrode material, or solid electrolyte material is collected by the powder scraping method, the elements are analyzed by inductively coupled plasma atomic emission spectrometry (ICP-OES), the emission intensity of each element at the corresponding wavelength is tested, and the element content is determined by combining the external standard method.

[0067] In this application, the chemical formulas of the compounds in the separator layer are tested using conventional methods in the art; for example, the elements and contents of the separator layer material are tested according to the method described in the previous paragraph, and then the chemical formulas of the compounds in the separator layer are obtained based on the test results.

[0068] In some embodiments, the separator layer comprises 2.74%-20.73%, 4.7%-20.1%, or 4.67%-8.05% of the volume of the solid-state battery cell, for example, 2.74%, 3%, 3.3%, 3.5%, 3.7%, 4%, 4.2%, 4.4%, 4.67%, 4.7%, 4.8%, 5%, 5.3%, 5.5%, 5.7%, 5.8%, 5.94%, 6%, and 6%. The percentages are 3%, 6.5%, 6.6%, 7%, 7.1%, 7.3%, 7.5%, 7.6%, 8%, 8.05%, 8.3%, 8.5%, 8.7%, 9%, 9.5%, 10%, 10.5%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 20.1%, 20.3%, 20.5%, 20.73%, or any combination of the above values. Therefore, on the one hand, the separator layer can effectively separate the positive electrode active material from the solid electrolyte and inhibit their reaction, thereby improving the cycle stability of the battery cell; on the other hand, it reduces the negative impact of the increased volume fraction of the separator layer on the fast-charging performance and energy density of the battery cell, and also reduces the impact of polarization caused by the increased volume fraction of the separator layer on the cycle stability of the battery cell.

[0069] In this application, the volume of a solid-state battery cell is calculated by measuring the length, thickness, and height of the battery cell casing (generally excluding the height of the electrode terminals and the insulating film outside the casing).

[0070] In this application, the volume ratio of the separator layer in the solid-state battery cell is tested using conventional methods in the art; for example, the length, thickness, and height of the battery cell are measured, and the volume of the battery cell is calculated; the electrode assembly in the battery cell is removed, and the solid electrolyte with the separator layer is disassembled. The length and height of the solid electrolyte are measured using a micrometer and can be regarded as the length and height of the separator layer; the separator layer and solid electrolyte are cut along the arrangement direction using an ion beam, and the thickness of the separator layer on the cross section is measured by SEM or FIB-SIMS. Multiple tests are performed and the average value is taken; the volume of the separator layer is calculated based on the thickness, length, and height of the separator layer, and then the volume ratio of the separator layer in the solid-state battery cell is calculated.

[0071] Another embodiment of this application provides a method for preparing a solid-state battery cell, which is either method one or method two;

[0072] Method 1 includes the following steps:

[0073] Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The solid electrolyte containing sulfides is dispersed on one side and then subjected to a first cold pressing to obtain a solid electrolyte with a separator layer on one side.

[0074] The negative electrode is placed on the other side of the solid electrolyte, and the positive electrode is placed on the side of the separator away from the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell.

[0075] The second method includes the following steps:

[0076] Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The positive electrode sheet is dispersed on the side that is close to the solid electrolyte, and after a first cold pressing, a positive electrode sheet with a separator layer on one side is obtained;

[0077] The solid electrolyte is placed on the side of the separator layer away from the positive electrode, and the negative electrode is placed on the other side of the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell.

[0078] Wherein, A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or any range of the above values; 0 ≤ a ≤ 2, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 The range of values ​​is 0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or any of the above values; 0 < b ≤ 0.25, for example, 0.01, 0.03, 0.05, 0.08, 0.1, 0.11, 0.13, 0.14, 0.15, 0.16, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, or any of the above values; when the valence states of elements in A and B are equal or B does not exist, n = 0; when the valence states of elements in A and B are not equal, n = x.

[0079] Therefore, this application provides a mixture containing the compound Li between the positive electrode and the solid electrolyte. 3-n A 1-x B x Cl 6-a-b Br a F b The separator layer can effectively suppress the side reactions between the positive electrode active material and the sulfide-containing solid electrolyte. Furthermore, the aforementioned compounds in the separator layer are not easily reacted with the sulfides in the solid electrolyte and have high stability, which reduces the generation of by-products and improves the cycle stability of the battery cell. In addition, the reduction of by-products lowers the impedance of the battery cell and improves the fast charging performance of the battery cell.

[0080] In some embodiments, the pressure of the first cold press is 250-340 MPa, for example, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 300 MPa, 310 MPa, 320 MPa, 330 MPa, 340 MPa, or any range of the above values; and / or,

[0081] The first cold pressing time is 10-60 seconds, for example, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds or any range of the above values.

[0082] In some embodiments, the pressure of the second cold pressing is 300-650 MPa, for example, 300 MPa, 320 MPa, 340 MPa, 360 MPa, 380 MPa, 400 MPa, 420 MPa, 450 MPa, 470 MPa, 500 MPa, 520 MPa, 540 MPa, 550 MPa, 560 MPa, 600 MPa, 610 MPa, 630 MPa, 650 MPa, or any range of the above values; and / or,

[0083] The second cold pressing time is 180-360 seconds, for example, 180 seconds, 200 seconds, 220 seconds, 240 seconds, 250 seconds, 270 seconds, 300 seconds, 330 seconds, 340 seconds, 350 seconds, 360 seconds or any range of the above values.

[0084] In some embodiments, the mass ratio of the compound to the solid electrolyte is (10-40):(60-90), for example, 10:90, 20:80, 30:70, 40:60, or any range of the above values.

[0085] In some embodiments, the compound includes Li3YCl4Br 1.9 F 0.1 ,Li3HoCl4Br 1.8 F 0.2 ,Li3HoCl4Br 1.9 F 0.1 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F 0.1 Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F 0.1 Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F0.1 Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 Li 2.6 Y 0.6 Zr 0.4 Cl 4.5 Br 1.4 F 0.1 Li 2.4 Yb 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 Li 2.5 Yb 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 Li 2.5 Er 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 One or more of them.

[0086]

Positive Electrode

[0087] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0088] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0089] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0090] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0091] During the charging and discharging process of a battery, Li undergoes insertion / extraction and consumption, resulting in varying molar Li content at different discharge states. In the examples of cathode materials in this application, the molar Li content refers to the initial state of the material, i.e., the state before feeding. When the cathode material is applied to the battery system, the molar Li content changes after charge-discharge cycles.

[0092] In the examples of cathode materials in this application, the molar content of O is only a theoretical value. Oxygen release from the crystal lattice will cause changes in the molar content of oxygen, and the actual molar content of O will fluctuate.

[0093] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0094] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0095] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0096] [Negative electrode plate]

[0097] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0098] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0100] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0101] As an example, the negative electrode active material can be any negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: carbon materials (such as artificial graphite, natural graphite, soft carbon, hard carbon, etc.), alloy materials (such as lithium-alloys, etc.), compound materials (such as lithium-silicon dioxide, lithium titanate, etc.), and novel negative electrode materials (such as silicon-based materials, tin-based materials, etc.). Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0102] As an example, negative electrode active materials can be filled or / and deposited within the negative electrode current collector.

[0103] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0104] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0105] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0106] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0107] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0108] Electrolytes

[0109] In some embodiments, the battery cell also includes a solid electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of solid electrolyte; it can be selected according to requirements.

[0110] As an example, solid electrolytes can be sulfide solid electrolytes (crystalline lithium superion conductors (lithium germanium phosphate sulfur, silver sulfide germanium), amorphous sulfides).

[0111] As an example, the solid electrolyte can be a sulfide solid electrolyte, such as Li6PS5Cl, Li2S, P2S5, Li7P3S. 11 Li 10 GeP2S 12 wait.

[0112] In some embodiments, the solid electrolyte may also include sulfides of elements such as aluminum, phosphorus, silicon, titanium, and tin to improve the performance of the solid electrolyte.

[0113] In some embodiments, the solid electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0114] As an example, solid electrolytes may further include polymers such as polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0115] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0116] [Structure of the Electrode Assembly]

[0117] The electrode assembly can be a wound structure, a stacked structure, or a hybrid structure of wound and stacked.

[0118] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0119] In some implementations, the electrode assembly is a stacked structure.

[0120] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0121] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0122] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0123] As an example, a solid electrolyte is placed between any two adjacent positive or negative electrodes.

[0124] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0125] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0126]

shell

[0127] In some embodiments, the battery cell may include a casing. The casing may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), a composite metal casing (such as a copper-aluminum composite casing), or an aluminum-plastic film, etc. In some embodiments, the casing may be a sealed structure or a non-sealed structure. As an example, when the casing is a non-sealed structure, the casing serves to protect the electrode assembly, and a sealing bag is included between the casing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag may be a bag-shaped insulating component or an aluminum-plastic film. When the casing is a sealed structure, it is used to encapsulate components such as the electrode assembly and electrolyte.

[0128] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0129] In some embodiments, the housing includes an end cap and a housing, the housing having an opening, and the end cap covering the opening. The housing may have one or more openings. The end cap may also have one or more.

[0130] Electrode terminals

[0131] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab. The electrode terminal can be directly connected to the tab, or it can be indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0132] Pressure relief mechanism

[0133] In some embodiments, a pressure relief mechanism is provided on the casing. The pressure relief mechanism is used to release the internal gas of the battery cell.

[0134] As an example, the internal pressure or temperature of a battery cell is actuated to release the internal pressure or temperature when it reaches a predetermined threshold. When the internal pressure or temperature of the battery cell reaches the predetermined threshold, the pressure relief mechanism is activated or a weak structure in the pressure relief mechanism is broken, thereby creating an opening or channel for the internal pressure or temperature to be released. The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell.

[0135] As an example, the pressure relief mechanism can be integrally molded with the housing.

[0136] As an example, the pressure relief mechanism can also be separately installed and connected to the housing.

[0137] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure and temperature of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to: movement of components within the mechanism to form an exhaust channel, rupture, breakage, tearing, or opening of at least a portion of the mechanism, etc. When the pressure relief mechanism is activated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the activated portion. This method allows for pressure and temperature relief of the battery cell under controllable pressure or temperature, thereby preventing potentially more serious accidents.

[0138] In some embodiments, when the housing is a non-sealed structure, the pressure relief mechanism can be configured as a through hole for venting gas inside the battery cell.

[0139] The emissions from battery cells mentioned in this application include, but are not limited to: electrolytes, dissolved or split positive and negative electrode plates, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0140] [Battery Device]

[0141] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0142] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0143] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0144] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0145] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0146] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0147] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0148] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0149] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0150] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use individual battery cells, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0151] For example, Figure 1 The example shown is a square-structured battery cell 5.

[0152] In some implementations, refer to Figure 2The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. The positive electrode, negative electrode, and solid electrolyte may be formed into an electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, which can be selected by those skilled in the art according to specific practical needs.

[0153] In some implementations, individual battery cells can be assembled into a battery module. The number of individual battery cells contained in a battery module can be one or more, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery module.

[0154] Figure 3 This is battery module 4, used as an example. (See reference...) Figure 3 In battery module 4, multiple battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells 5 can be fixed in place using fasteners.

[0155] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0156] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0157] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0158] In addition, this application also provides an electrical device, which includes at least one of the battery cell, battery module, or battery pack provided in this application. The battery cell, battery module, or battery pack can be used as the power source of the electrical device or as the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0159] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0160] Figure 6 This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of individual battery cells, a battery pack or battery module can be used.

[0161] [Example]

[0162] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0163] Table 1 Chemical formulas of compounds 1-15

[0164]

[0165]

[0166] Example 1

[0167] (1) Preparation of positive electrode sheet: The positive electrode active material LiNi 0.83 Co 0.12 Mn 0.05 O2, polyvinylidene fluoride (PVDF) binder, and conductive carbon are mixed in a mass ratio of 93:4.5:2.5. N-methylpyrrolidone (NMP) solvent is added and stirred until the system is homogeneous to obtain a positive electrode slurry (solid content of 70% by mass). The positive electrode slurry is uniformly coated on both sides of the positive electrode current collector aluminum foil, dried at room temperature, transferred to an oven for further drying, and then cut into positive electrode sheets.

[0168] (2) Negative electrode sheet: A Li-In metal foil with a thickness of 0.3-0.5mm is rolled onto one side of a copper foil with a thickness of 0.1mm, and then cut into a negative electrode sheet.

[0169] (3) Solid electrolyte: Li6PS5Cl was used. 100 mg of Li6PS5Cl was first added to the mold and the powder was cold-pressed at 260 MPa for 30 seconds to obtain the solid electrolyte.

[0170] (4) Preparation of battery cells: 25 mg of compound 10 was uniformly dispersed on one side of the solid electrolyte and cold-pressed at 260 MPa for 60 seconds to form a separator layer on the solid electrolyte side. The positive electrode was placed on the side of the separator layer away from the solid electrolyte, and the negative electrode was placed on the other side of the solid electrolyte. The separator layer was cold-pressed at 340 MPa for 200 seconds to obtain the electrode assembly. The thickness of the separator layer was 0.057 mm, which was 6% of the thickness of the solid electrolyte layer. The separator layer accounted for 5.94% of the volume of the battery cell. The electrode assembly was wrapped in an aluminum-plastic film bag and dried. After encapsulation and other processes, the battery cell was obtained.

[0171] Battery cell testing

[0172] Battery cell cycle capacity retention test: After the battery cell was left to stand for 5 hours, it was charged at a constant current of 0.1C to 4.3V at an ambient temperature of 25℃, then left to stand for 10 minutes, and discharged at a constant current of 0.1C to 2.8V. This charge-discharge cycle was repeated twice for formation. Then, it was charged at a constant current of 0.33C to 4.3V, left to stand for 10 minutes, and discharged at a constant current of 0.33C to 2.8V, obtaining the first discharge capacity C0. The above charge-discharge process was repeated 100 times, and the discharge capacity C100 of the last cycle was recorded. The cycle capacity retention rate S of the battery cell was calculated according to the following formula.

[0173] S = 100% × C100 / C0.

[0174] Battery cell full-charge impedance test after the first cycle: The battery cell was charged at a constant current of 0.1C to 4.3V, then charged at a constant voltage to 0.05C, then discharged at 0.1C to 2.8V, and then charged at a constant current of 0.1C to 4.3V for full charge. Electrochemical impedance spectroscopy (EIS) was used to test the battery cell at room temperature, with an AC frequency of 10 Hz. 6 -10 -2 At Hz and a voltage of 50mV, the AC impedance response of a single battery cell was recorded and measured. The EIS spectrum was fitted using an equivalent circuit to obtain the full-charge impedance of the battery cell after the first cycle, in Ω.

[0175] Energy density test of individual battery cells:

[0176] Place the battery cell in an ambient temperature of 25℃, charge it to 4.3V with a constant current of 0.33C, let it stand for 10 minutes, and discharge it to 2.8V with a constant current of 0.33C. Record the discharge capacity A0 and the discharge plateau voltage V at this time. Weigh the battery cell M (generally weigh the battery cell by its outer shell, excluding the height of the electrode terminals and the insulating film outside the shell). The energy density of the battery cell VED = (A0 × V) / M, in Wh / g.

[0177] Examples 2-15 and Comparative Examples 1-3

[0178] (1)-(3) are the same as steps (1)-(3) in Example 1;

[0179] In steps (4) of Examples 2-15 and Comparative Examples 1-2, compounds 11 to 15, 4 to 9, 1 to 3, Li3YCl6 and Li3YCl4Br2 were added respectively, and the amount added was adjusted so that the thickness of the separator layer was the same as that of Example 1. At the same time, the thickness ratio of the separator layer to the solid electrolyte and the proportion of the separator layer in the battery cell volume were also the same as those of Example 1. The remaining operations were the same as step (4) of Example 1.

[0180] In Comparative Example 3, step (4) was performed without adding any compound, and the rest was the same as step (4) in Example 1.

[0181] Table 2. Parameters and test results for Examples 1-15 and Comparative Examples 1-3.

[0182]

[0183] It can be seen from the above table:

[0184] Compared with Comparative Examples 1 and 3, the separation layer of compounds 1-15 in this application significantly improves the cycle performance of the battery cell, significantly reduces the full charge impedance after the first cycle, and significantly improves the fast charge performance.

[0185] Compared with Comparative Example 2, the present application includes a separator layer of compounds 1-15, which significantly improves the cycle performance of the battery cell.

[0186] Examples 16-19

[0187] (1)-(3) are the same as steps (1)-(3) in Example 1;

[0188] Adjust the mass of compound 1 in step (4) of Examples 16-19 so that the ratio of the thickness of the separator to the thickness of the solid electrolyte is 4%, 8%, 2%, and 15%, respectively. The remaining operations are the same as step (4) of Example 1.

[0189] Table 3. Parameters and test results for Examples 1 and 16-19

[0190]

[0191] It can be seen from the above table:

[0192] Compared with Examples 18-19, Examples 1 and 16-17 of this application use a separator layer to solid electrolyte thickness ratio of 6%, 4%, and 8%, which significantly improves the cycle performance of the battery cells.

[0193] Compared with Example 19, Examples 1 and 16-17 of this application use a separation layer to solid electrolyte thickness ratio of 6%, 4%, and 8%, which results in lower full-charge impedance, significantly improved fast-charging performance, and significantly improved energy density of the battery cells after the first cycle.

[0194] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A solid-state battery cell, comprising a positive electrode, a negative electrode, and a solid electrolyte; the solid electrolyte comprising a sulfide; the positive electrode comprising a positive electrode material; a separator layer comprising a compound Li 3-n A 1-x B x Cl 6-a-b Br a F b ;in, A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7; 0 ≤ a ≤ 2; 0 < b ≤ 0.25; when the elements in A and B have the same valence state or when B does not exist, n = 0; When the valence states of the elements in A and B are not equal, n = x.

2. The solid-state battery cell according to claim 1, wherein, The thickness of the separator layer is 2%-15% or 4%-8% of the thickness of the solid electrolyte.

3. The solid-state battery cell according to claim 1 or 2, wherein, The thickness of the separator layer is 0.028-0.173 mm, 0.045-0.072 mm, or 0.04-0.15 mm.

4. The solid-state battery cell according to any one of claims 1 to 3, wherein, The separator layer, the positive electrode material, and the solid electrolyte comprise one or more characteristic elements selected from Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, In, Ti, Zr, Hf, and Rf.

5. The solid-state battery cell according to claim 4, wherein, The mass content of the characteristic element in the separator layer is 19%-32% or 21%-30%.

6. The solid-state battery cell according to any one of claims 1 to 5, wherein, The separator layer and / or the positive electrode material include halogens; and / or, The halogen content in the separator layer is 65%-75% or 67%-74% by mass.

7. The solid-state battery cell according to any one of claims 1 to 6, wherein, The compounds include Li3YCl4Br 1.9 F 0.1 、Li3HoCl4Br 1.8 F 0.2 、Li3HoCl4Br 1.9 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 、Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 、Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F 0.1 、Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.6 Y 0.6 Zr 0.4 Cl 4.5 Br 1.4 F 0.1 、Li 2.4 Yb 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Yb 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Er 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 One or more of them.

8. The solid-state battery cell according to any one of claims 1 to 7, wherein, The volume fraction of the separator layer in the battery cell is 2.74%-20.73%, 4.7%-20.1%, or 4.67%-8.05%.

9. A method for preparing a solid-state battery cell, which is either method one or method two; Method 1 includes the following steps: Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The solid electrolyte containing sulfides is dispersed on one side and then subjected to a first cold pressing to obtain a solid electrolyte with a separator layer on one side. The negative electrode is placed on the other side of the solid electrolyte, and the positive electrode is placed on the side of the separator away from the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell. The second method includes the following steps: Compound Li 3-n A 1-x B x Cl 6-a-b Br a F b The positive electrode sheet is dispersed on the side that is close to the solid electrolyte, and after a first cold pressing, a positive electrode sheet with a separator layer on one side is obtained; The solid electrolyte is placed on the side of the separator layer away from the positive electrode, and the negative electrode is placed on the other side of the solid electrolyte. After a second cold pressing, the cells are packaged to obtain a solid-state battery cell. in, A includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, B, Al, Ga, and In; B includes any one of the elements Sc, Y, La, Ce, Nd, Gd, Dy, Ho, Er, Yb, Ti, Zr, Hf, and Rf; the elements in A and B are different; 0 ≤ x ≤ 0.7; 0 ≤ a ≤ 2; 0 < b ≤ 0.25; when the elements in A and B have the same valence state or when B does not exist, n = 0; When the valence states of the elements in A and B are not equal, n = x.

10. The method according to claim 9, wherein, The pressure of the first cold press is 250-340 MPa; and / or, The first cold pressing time is 10-60 seconds.

11. The method according to claim 9 or 10, wherein, The pressure of the second cold press is 300-650 MPa; and / or, The second cold pressing time is 180-360 seconds.

12. The method according to any one of claims 9 to 11, wherein, The mass ratio of the compound to the solid electrolyte is (10-40):(60-90).

13. The method according to any one of claims 9 to 12, wherein, The compounds include Li3YCl4Br 1.9 F 0.1 、Li3HoCl4Br 1.8 F 0.2 、Li3HoCl4Br 1.9 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.5 Br 1.3 F 0.2 、Li3Y 0.6 In 0.4 Cl 4.4 Br 1.5 F 0.1 、Li3Y 0.6 In 0.4 Cl 4.3 Br 1.4 F 0.2 、Li3Y 0.4 In 0.6 Cl 4.5 Br 1.4 F 0.1 、Li3Y 0.4 In 0.6 Cl 4.4 Br 1.5 F 0.1 、Li 2.4 Y 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.6 Y 0.6 Zr 0.4 Cl 4.5 Br 1.4 F 0.1 、Li 2.4 Yb 0.4 Zr 0.6 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Yb 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 、Li 2.5 Er 0.5 Zr 0.5 Cl 4.5 Br 1.4 F 0.1 Li 2.3 Ga 0.3 Zr 0.7 Cl 4.5 Br 1.4 F 0.1 One or more of them.

14. A battery device comprising a solid-state battery cell according to any one of claims 1 to 8 or a solid-state battery cell prepared by the method according to any one of claims 9 to 13.

15. An electrical device comprising a solid-state battery cell as described in any one of claims 1 to 8 or a battery device as described in claim 14.

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