Laminated battery cell and preparation method thereof, all-solid-state battery and electric equipment

Abstract

The invention provides a laminated cell and a preparation method thereof, an all-solid-state battery and electric equipment, and belongs to the technical field of all-solid-state battery manufacturing. The preparation method of the laminated battery cell comprises the following steps: performing lamination treatment and pressing treatment on negative pole pieces, solid electrolyte membranes and positive pole pieces, so that any adjacent negative pole piece and positive pole piece are separated by the solid electrolyte membranes, the coating area of the negative pole piece, the solid electrolyte membrane and the coating area of the positive pole piece are the same in shape and size; the edge of at least part of the non-tab area of the battery cell precursor is cut in the circumferential direction of the battery cell precursor to obtain the laminated battery cell, and the problem that the open-circuit voltage of an all-solid-state battery is low can be solved to a certain extent through the preparation method of the laminated battery cell; and popularization and application of the all-solid-state battery in the technical field of energy storage are facilitated.

Description

Technical Field

[0001] This application relates to the field of all-solid-state battery manufacturing technology, and more specifically, to a stacked cell and its preparation method, an all-solid-state battery, and an electrical device. Background Technology

[0002] Solid-state batteries have become a key research focus in the field of energy storage technology due to their high energy density and excellent safety. However, a common problem in solid-state batteries is the high interfacial impedance between the solid electrolyte membrane and the electrodes. To improve this, external pressure is usually applied during the assembly and subsequent operation of solid-state batteries. However, solid-state batteries prepared by existing processes suffer from low open-circuit voltage, which limits their promotion and application. Summary of the Invention

[0003] The purpose of this application is to provide a stacked battery cell and its preparation method, an all-solid-state battery, and an electrical device, which can improve the problem of low open-circuit voltage of all-solid-state batteries to a certain extent, thereby helping the promotion and application of all-solid-state batteries in the field of energy storage technology.

[0004] The embodiments of this application are implemented as follows: In a first aspect, embodiments of this application provide a method for preparing a laminated battery cell, comprising the following steps: The negative electrode, solid electrolyte membrane, and positive electrode are stacked and pressed together so that any adjacent negative and positive electrode are separated by the solid electrolyte membrane. The coating area of ​​the negative electrode, the solid electrolyte membrane, and the coating area of ​​the positive electrode are all the same in shape and size, thus obtaining a cell precursor. At least a portion of the edge of the non-tab area of ​​the cell precursor is cut along the circumference of the cell precursor to obtain a stacked cell.

[0005] In the above technical solution, the stacked battery cell is prepared according to the aforementioned process. On the one hand, the coating areas of the negative electrode, the solid electrolyte membrane, and the coating areas of the positive electrode are all the same in shape and size, meaning that after stacking, they can be overlapped relatively neatly. In the subsequent lamination process, this effectively improves the problem of internal short circuits caused by edge deformation due to size mismatch between the negative electrode, the solid electrolyte membrane, and the positive electrode. On the other hand, after obtaining the cell precursor, at least a portion of the edges of the non-tab area of ​​the cell precursor are cut along its circumference, removing at least a portion of the irregular edge areas. This also helps increase the overall regularity of the stacked battery cell and improves the problem of internal short circuits caused by edge deformation due to size mismatch under external pressure (such as during isostatic pressing). Through the combined effect of these two aspects, a stacked battery cell with smaller edge deformation and a more regular overall structure can be prepared, thereby improving the problem of low open-circuit voltage in all-solid-state batteries to a certain extent.

[0006] In some alternative implementations, the edges of all regions of the non-tab area of ​​the cell precursor are cut along the circumference of the cell precursor.

[0007] In the above technical solution, the edges of all areas of the non-tab region of the cell precursor are cut along the circumference of the cell precursor, that is, all edge areas with poor regularity are removed. This can further increase the overall regularity of the stacked cell, thereby better improving the problem of internal short circuit caused by the deformation of the edge area due to size mismatch under external pressure (such as the isostatic pressing stage).

[0008] In some alternative implementations, the width of the cut area is 0.3 to 1.0 mm during the cutting process.

[0009] In the above technical solution, limiting the cutting specifications to the above range during the cutting process can thoroughly remove the edge areas with poor regularity, while also reducing material waste and lowering the manufacturing cost of stacked cells.

[0010] In some alternative implementations, the cutting method in the cutting process is selected from at least one of laser cutting and metal die cutting.

[0011] The above technical solutions offer a variety of cutting methods and provide numerous feasible solutions, thus facilitating the promotion and application of the technical solutions provided in this application.

[0012] In some alternative implementations, the cutting process is carried out using laser cutting.

[0013] In the above technical solution, laser cutting is used. Laser cutting does not require physical contact, which can reduce the probability of burrs appearing on the cut surface of the material (especially the positive and negative current collectors) after cutting (burrs on the current collector can easily lead to internal short circuits). At the same time, high-energy laser combined with auxiliary gas purging can effectively remove material debris generated during the cutting process (the presence of material debris can also easily lead to internal short circuits), which helps to reduce the risk of internal short circuits in the all-solid-state battery corresponding to the stacked cells during use.

[0014] In some alternative implementations, the laser power is 1~3 KW, or / and the cutting speed is 1~10 m / min during the laser cutting process.

[0015] In the above technical solution, the laser power and cutting speed are limited within the above range during the laser cutting process, which can better balance the cutting efficiency and the flatness of the cut surface.

[0016] In some alternative implementations, the pressing process satisfies at least one of the following conditions A through C: A. Apply pressure of 1~20 MPa.

[0017] B. The pressurization time is 10~600 s.

[0018] C. The processing temperature is 50~100℃.

[0019] In the above technical solution, in the pressing process, the applied pressure, pressing time and processing temperature are limited to the above range, which enables the adjacent functional layers to be tightly bonded, which helps to degrade the interfacial impedance between the solid electrolyte membrane and the electrode, and at the same time, it is not easy to cause damage to each functional layer.

[0020] In some alternative implementations, the negative electrode tab in the negative electrode sheet has the same shape and size as the positive electrode tab in the positive electrode sheet.

[0021] In the above technical solution, the negative electrode tab in the negative electrode sheet and the positive electrode tab in the positive electrode sheet are set to have the same shape and size, so that the final stacked cell has the advantage of a more regular overall structure.

[0022] In some alternative implementations, the number of positive electrodes in the laminated cell is N, and the number of negative electrodes is N+1.

[0023] In the above technical solution, the number of negative electrode sheets in the laminated cell is greater than the number of positive electrode sheets, so that the bottom and top layers of the prepared laminated cell are both negative electrode sheets. This can effectively reduce the risk of lithium dendrite formation in the laminated cell. At the same time, the plastic deformation capability of the negative electrode sheet is better than that of the positive electrode sheet, which can improve the structural stability of the laminated cell.

[0024] In some alternative implementations, the number of positive electrode plates is 5 to 15.

[0025] In the above technical solution, limiting the number of positive electrode sheets in the stacked cells to the above range can better accommodate various commonly used all-solid-state battery specifications.

[0026] Secondly, embodiments of this application provide a laminated battery cell, which is prepared using the method for preparing a laminated battery cell as provided in the first aspect embodiment.

[0027] In the above technical solution, the stacked battery cell is prepared by the method of preparing the stacked battery cell provided in the first aspect embodiment. The stacked battery cell prepared by this method has the advantages of small deformation in the edge area and relatively regular overall structure, which can improve the problem of low open circuit voltage of the corresponding all-solid-state battery to a certain extent.

[0028] Thirdly, embodiments of this application provide an all-solid-state battery, including the stacked cells provided in the second aspect of the embodiments.

[0029] In the above technical solution, the all-solid-state battery includes the stacked cells provided in the second aspect embodiment. Since the stacked cells have the advantages of small deformation in the edge area and relatively regular overall structure, they can improve the problem of low open-circuit voltage of all-solid-state batteries to a certain extent.

[0030] Fourthly, embodiments of this application provide an electrical device including an all-solid-state battery as provided in the third aspect embodiment. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a process flow diagram of a method for preparing a laminated battery cell provided in an embodiment of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0034] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", all refer to the three cases of "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".

[0035] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two endpoints "a" and "b"; and "unit of measurement" in "numerical value a to numerical value b + unit of measurement" represents the "unit of measurement" of both "numerical value a" and "numerical value b".

[0036] Currently, all-solid-state batteries fabricated using existing processes generally suffer from low open-circuit voltages, thus limiting their promotion and application. The inventors have discovered that one reason for this problem is that the mainstream approach for stacked cells in current all-solid-state batteries still employs the layering assembly process of liquid batteries. This means that the positive electrode, negative electrode, and all-solid-state electrolyte membrane all have dimensional differences. Furthermore, stacking precision issues are unavoidable during the stacking process. In addition, all-solid-state batteries require external forces during fabrication and subsequent applications (specifically, pressing is required during cell fabrication to achieve tight bonding between functional layers; isostatic pressing is required during all-solid-state battery fabrication; and external forces are needed to reduce the interfacial impedance between the solid electrolyte membrane and the electrodes). Dimensional mismatches during pressurization can easily lead to deformation of the component's edge areas, causing internal short circuits and ultimately resulting in low open-circuit voltages in all-solid-state batteries.

[0037] To address the issue of low open-circuit voltage in all-solid-state batteries due to size mismatch, engineers devised a method to add an insulating filler strip between the edges of the positive and negative electrodes. However, due to limitations in filling precision (it is usually difficult to completely fill the size difference between the edges of the positive and negative electrodes), this technique is not very effective in improving the open-circuit voltage of all-solid-state batteries. Furthermore, it makes the manufacturing process of stacked cells more complicated and reduces the production efficiency of stacked cells.

[0038] Based on this, the inventors further discovered that by using electrodes of the same shape and size and solid electrolyte membranes as the materials for preparing stacked cells, and by adding a cutting process to the edges of the non-tab area of ​​the cell after lamination, the problem of low open-circuit voltage in all-solid-state batteries can be effectively improved. Furthermore, compared with the technical solution of adding insulating filler strips, the technical solution provided in this application also has the advantage of being simple and easy to implement, so that the production efficiency of stacked cells can still be maintained at a high level.

[0039] It should be noted that the cutting process is added to the edge of the non-tab area of ​​the cell after the lamination process. This is because there are unavoidable differences in precision during the lamination process. Even if the same shape and size of the electrode and solid electrolyte membrane are used for lamination, the vertical projection of each functional layer in the prepared laminated cell will be deviated. That is, there is a problem that the edges cannot be completely overlapped. This will also lead to the problem of low open circuit voltage in the final prepared all-solid-state battery.

[0040] The following is a detailed description of a stacked battery cell, its preparation method, an all-solid-state battery, and an electrical device according to embodiments of this application.

[0041] In a first aspect, embodiments of this application provide a method for preparing a laminated battery cell, comprising the following steps: The negative electrode, solid electrolyte membrane, and positive electrode are stacked and pressed together so that any adjacent negative and positive electrode are separated by the solid electrolyte membrane. The coating area of ​​the negative electrode, the solid electrolyte membrane, and the coating area of ​​the positive electrode are all the same in shape and size, thus obtaining a cell precursor. At least a portion of the edge of the non-tab area of ​​the cell precursor is cut along the circumference of the cell precursor to obtain a stacked cell.

[0042] In this application, the laminated cell is prepared according to the above-mentioned process. On the one hand, the coating areas of the negative electrode, the solid electrolyte membrane, and the coating areas of the positive electrode are all the same in shape and size, meaning that the three can be stacked together relatively neatly after lamination. In the subsequent pressing process, this effectively improves the problem of edge deformation and internal short circuits caused by size mismatch between the negative electrode, the solid electrolyte membrane, and the positive electrode. On the other hand, after obtaining the cell precursor, at least a portion of the edge of the non-tab area of ​​the cell precursor is cut along its circumference, i.e., at least a portion of the irregular edge area is removed. This also helps to increase the overall regularity of the laminated cell and improves the problem of edge deformation and internal short circuits caused by size mismatch under external pressure (such as the isostatic pressing stage). Through the combined effect of these two aspects, a laminated cell with smaller edge deformation and a more regular overall structure can be prepared, thereby improving the problem of low open-circuit voltage in the corresponding all-solid-state battery to a certain extent.

[0043] It should be noted that the wafer stacking process can be performed according to conventional processes in this field.

[0044] It should be noted that in the step of cutting the edge of at least a portion of the non-tab region of the battery cell precursor along the circumference of the battery cell precursor, the selection of the cutting area is not limited and can be adapted according to actual needs.

[0045] To better understand the technical solution, a possible implementation method is described here. For example, the coating area of ​​the negative electrode, the solid electrolyte membrane, and the coating area of ​​the positive electrode are all rectangles of the same size, and the negative electrode tab and the positive electrode tab in the cell precursor are located on the same side. In the step of cutting the edge of a part of the area, one side, two sides, three sides, or three sides of the non-tab side and the non-tab area of ​​the tab side can be cut off.

[0046] As an example, along the circumference of the cell precursor, the edges of all regions of the non-tab area of ​​the cell precursor (i.e., the three sides of the non-tab side and the non-tab area of ​​the tab side) are cut.

[0047] In this embodiment, the edges of all areas of the non-tab region of the cell precursor are cut along the circumference of the cell precursor, that is, all edge areas with poor regularity are removed. This can further increase the overall regularity of the stacked cell, thereby better improving the problem of internal short circuit caused by edge deformation due to size mismatch under external pressure (such as the isostatic pressing stage).

[0048] As an example, in the cutting process, the width of the cut area is 0.3 to 1.0 mm, for example, but not limited to any one of 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm and 1.0 mm or any range between two.

[0049] In this embodiment, limiting the cutting specifications to the above range during the cutting process can thoroughly remove edge areas with poor regularity, while also reducing material waste and lowering the manufacturing cost of stacked cells.

[0050] It should be noted that the cutting method is not limited and can be carried out in accordance with conventional methods in this field.

[0051] As an example, in the cutting process, the cutting method is selected from at least one of laser cutting and metal die cutting.

[0052] In this embodiment, there are many cutting methods that can be used for the cutting process, which can provide a variety of feasible solutions, thereby facilitating the promotion and application of the technical solutions provided in the embodiments of this application.

[0053] As an example, the cutting process uses laser cutting.

[0054] In this embodiment, laser cutting is used. Laser cutting does not require physical contact, which can reduce the probability of burrs appearing on the cut surface of the material (especially the positive and negative current collectors) after cutting (burrs on the current collectors can easily lead to internal short circuits). At the same time, the high-energy laser combined with auxiliary gas purging can also effectively remove a small amount of material debris generated during the cutting process (the presence of material debris can also easily lead to internal short circuits), which helps to reduce the risk of internal short circuits in the all-solid-state battery corresponding to the stacked cells during use.

[0055] As an example, during laser cutting, the laser power is 1~3 KW, for example, but not limited to any one of 1KW, 1.5 KW, 2 KW, 2.5 KW and 3 KW or any range between two; and / or the cutting speed is 1~10 m / min, for example, but not limited to any one of 1m / min, 2 m / min, 3 m / min, 4 m / min, 5 m / min, 6 m / min, 7 m / min, 8 m / min, 9 m / min and 10 m / min or any range between two.

[0056] In this embodiment, during the laser cutting process, the laser power and cutting speed are limited to the above-mentioned ranges, which can better balance cutting efficiency and the flatness of the cut surface.

[0057] It should be noted that during the laser cutting process, the type and flow rate of the auxiliary gas can be set according to the conventional selection in this field.

[0058] As an example, in the pressing process, at least one of the following conditions A to C is satisfied: A. The applied pressure is 1 to 20 MPa, for example, but not limited to any one of 1 MPa, 5 MPa, 10 MPa, 15 MPa and 20 MPa or any range between two of them.

[0059] B. The pressurization time is 10 to 600 s, for example, but not limited to any one of the pressurization times of 10 s, 50 s, 100 s, 200 s, 300 s, 400 s, 500 s and 600 s, or any range between two of them.

[0060] C. The processing temperature is 50~100℃, for example, but not limited to any one of the processing temperatures of 50℃, 60℃, 70℃, 80℃, 90℃ and 100℃ or any range between two of them.

[0061] In this embodiment, during the pressing process, the applied pressure, pressing time, and processing temperature are limited to the above-mentioned ranges, which enables the adjacent functional layers to be tightly bonded, helps to degrade the interfacial impedance between the solid electrolyte membrane and the electrode, and at the same time, it is less likely to cause damage to each functional layer.

[0062] As an example, the negative electrode tab in the negative electrode sheet has the same shape and size as the positive electrode tab in the positive electrode sheet.

[0063] In this embodiment, the negative electrode tab in the negative electrode sheet and the positive electrode tab in the positive electrode sheet are set to have the same shape and size, so that the final stacked cell has the advantage of a more regular overall structure.

[0064] In other possible implementations, the negative electrode tab in the negative electrode sheet may be different in shape and size from the positive electrode tab in the positive electrode sheet.

[0065] As an example, in a laminated battery cell, the number of positive electrode plates is N, and the number of negative electrode plates is N+1.

[0066] In this embodiment, the number of negative electrode sheets in the laminated cell is greater than the number of positive electrode sheets, so that the bottom and top layers of the prepared laminated cell are both negative electrode sheets. This can effectively reduce the risk of lithium dendrite formation in the laminated cell. At the same time, the plastic deformation capability of the negative electrode sheet is better than that of the positive electrode sheet, which can improve the structural stability of the laminated cell.

[0067] It should be noted that the specific specifications of the laminated cells are not limited and can be adapted to actual needs.

[0068] As an example, the number of positive electrode plates is 5 to 15, such as, but not limited to, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15.

[0069] In this embodiment, limiting the number of positive electrode plates in the stacked cells to the above range can better accommodate various commonly used all-solid-state battery specifications.

[0070] It is understood that the preparation methods of the positive electrode, solid electrolyte membrane and negative electrode are not limited. For example, they can be prepared by dry process or wet process. In the specific embodiments of this application, the positive electrode, solid electrolyte membrane and negative electrode are all prepared by dry process. Since dry process and wet process are conventional technologies in the field, they are not described in detail in the embodiments of this application.

[0071] It is understandable that after obtaining the positive and negative electrode sheets through the dry process, the uncoated areas of the two need to be die-cut to form the positive and negative electrode tabs. The specific process can be carried out in accordance with the conventional process in this field.

[0072] It is understood that the specific composition of the positive electrode is not limited and can be set according to conventional choices in the art. Specifically, in the embodiments of this application, the material of the current collector in the positive electrode is aluminum foil, and the coating area on the current collector includes a ternary positive electrode, a sulfide solid electrolyte, a conductive agent, and a binder in a mass ratio of 6:2:1:1. Among them, the ternary positive electrode is selected from NCM811, the sulfide solid electrolyte is selected from at least one of LPS type, LGPS type, silver sulfide germanium type and Thio-LISICON type, the conductive agent is selected from at least one of Super P, VGCF and CNT, and the binder is selected from at least one of SEBS and PIB.

[0073] It is understood that the specific composition of the negative electrode sheet is not limited and can be set according to conventional choices in the art. Specifically, in the embodiments of this application, the material of the current collector in the negative electrode sheet is copper foil, and the coating area on the current collector includes a silicon negative electrode, a sulfide solid electrolyte, a conductive agent, and a binder in a mass ratio of 6:2:1:1. Among them, the silicon negative electrode is selected from at least one of nano-silicon, silicon oxide, and silicon-carbon composite materials; the sulfide solid electrolyte is selected from at least one of LPS type, LGPS type, silver sulfide germanium type, and Thio-LISICON type; the conductive agent is selected from at least one of Super P, VGCF, and CNT; and the binder is selected from at least one of SEBS and PIB.

[0074] It is understood that the specific composition of the solid electrolyte membrane is not limited and can be set in accordance with conventional choices in the art. Specifically, in the embodiments of this application, the solid electrolyte membrane includes a sulfide solid electrolyte and a binder in a mass ratio of 8:2; wherein, the sulfide solid electrolyte is selected from at least one of LPS type, LGPS type, thio-silver germanite type and Thio-LISICON type, and the binder is selected from at least one of SEBS and PIB.

[0075] It should be noted that, for the fabrication methods of laminated cells, any process steps not specifically described or limited can be performed in accordance with conventional methods in the field.

[0076] As an example, a process flow diagram of the fabrication method of laminated battery cells is exemplarily shown below. Figure 1 .

[0077] Secondly, embodiments of this application provide a laminated battery cell, which is prepared using the method for preparing a laminated battery cell as provided in the first aspect embodiment.

[0078] In this application, the stacked battery cell is prepared by the method of preparing the stacked battery cell provided in the first aspect embodiment. The stacked battery cell prepared by this method has the advantages of small deformation in the edge area and relatively regular overall structure, which can improve the problem of low open circuit voltage of the corresponding all-solid-state battery to a certain extent.

[0079] Thirdly, embodiments of this application provide an all-solid-state battery, including the stacked cells provided in the second aspect of the embodiments.

[0080] In this application, the all-solid-state battery includes the stacked cells provided in the second aspect embodiment. Since the stacked cells have the advantages of small deformation in the edge area and relatively regular overall structure, they can improve the problem of low open-circuit voltage of all-solid-state batteries to a certain extent.

[0081] It should be noted that the all-solid-state battery is obtained by encapsulating stacked cells and then performing isostatic pressing. The isostatic pressing process is a conventional technique in this field and will not be described in detail in the embodiments of this application.

[0082] Fourthly, embodiments of this application provide an electrical device including an all-solid-state battery as provided in the third aspect embodiment.

[0083] It should be noted that there are no restrictions on the type of electrical equipment, and the settings can be adapted according to actual needs. For example, electrical equipment can include mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, energy storage devices, and power tools.

[0084] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0085] Example 1 This application provides a method for preparing an all-solid-state battery, including the following steps: The ternary cathode (NCM811), sulfide solid electrolyte (Li6PS5Cl), conductive agent (Super P), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the cathode material region. Then, aluminum foil is used as the cathode current collector and a dry process is used to prepare the cathode sheet. The uncoated area of ​​the cathode sheet is then die-cut to form the cathode tab. The coated area of ​​the cathode sheet is a rectangle with a size of 60×50 mm.

[0086] The silicon anode (nano-silicon), sulfide solid electrolyte (Li6PS5Cl), conductive agent (CNT), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the anode material area. Then, copper foil is used as the anode current collector and a dry process is used to prepare the anode sheet. The uncoated area of ​​the anode sheet is then die-cut to form the anode tab. The coated area of ​​the anode sheet is a rectangle with a size of 60×50 mm.

[0087] The sulfide solid electrolyte (Li6PS5Cl) and binder (SEBS) were mixed at a mass ratio of 8:2 to obtain a mixture. Then, a sulfide solid electrolyte membrane was prepared by a dry process. The sulfide solid electrolyte membrane was a rectangle with a size of 60×50mm.

[0088] Eleven negative electrode sheets, eleven sulfide solid electrolyte membranes, and ten positive electrode sheets are stacked and pressed together. In the pressing process, a pressure of 10 MPa is applied for 200 s and the processing temperature is 60℃ to obtain a cell precursor with a specification of 10 positive and 11 negative electrodes, with the positive and negative electrode tabs located on the same side.

[0089] Along the circumference of the cell precursor, the edges of all areas of the non-tab region of the cell precursor are cut. The standard cut is 1 mm. The cutting method is laser cutting. The specific laser cutting parameters are: laser power of 1.5KW, cutting speed of 5 m / min, and auxiliary gas of nitrogen, to obtain the stacked cell.

[0090] After the stacked cells are packaged, they are subjected to isostatic pressing to obtain an all-solid-state battery.

[0091] Example 2 This application provides a method for preparing an all-solid-state battery, which differs from Example 1 only in that the cutting method is metal die-cutting.

[0092] Comparative Example 1 This application provides a comparative example of a method for preparing an all-solid-state battery, which differs from Example 1 only in that the edges of all regions of the non-tab area of ​​the cell precursor are not cut.

[0093] Comparative Example 2 This application provides a comparative example of a method for preparing an all-solid-state battery, comprising the following steps: The ternary cathode (NCM811), sulfide solid electrolyte (Li6PS5Cl), conductive agent (Super P), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the cathode material region. Then, aluminum foil is used as the cathode current collector and a dry process is used to prepare the cathode sheet. The uncoated area of ​​the cathode sheet is then die-cut to form the cathode tab. The coated area of ​​the cathode sheet is a rectangle with a size of 60×50 mm.

[0094] The silicon anode (nano-silicon), sulfide solid electrolyte (Li6PS5Cl), conductive agent (CNT), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the anode material area. Then, copper foil is used as the anode current collector and a dry process is used to prepare the anode sheet. The uncoated area of ​​the anode sheet is then die-cut to form the anode tab. The coated area of ​​the anode sheet is a rectangle with a size of 62×52 mm.

[0095] The sulfide solid electrolyte (Li6PS5Cl) and binder (SEBS) were mixed at a mass ratio of 8:2 to obtain a mixture. Then, a sulfide solid electrolyte membrane was prepared by a dry process. The sulfide solid electrolyte membrane was a rectangle with dimensions of 64×54mm.

[0096] Eleven negative electrode sheets, eleven sulfide solid electrolyte membranes, and ten positive electrode sheets are stacked and pressed together. In the pressing process, a pressure of 10 MPa is applied for 200 s and the processing temperature is 60℃ to obtain a stacked cell with a specification of 10 positive and 11 negative electrodes, with the positive and negative electrode tabs located on the same side.

[0097] After the stacked cells are packaged, they are subjected to isostatic pressing to obtain an all-solid-state battery.

[0098] Comparative Example 3 This application provides a comparative example of a method for preparing an all-solid-state battery, comprising the following steps: The ternary cathode (NCM811), sulfide solid electrolyte (Li6PS5Cl), conductive agent (Super P), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the cathode material region. Then, aluminum foil is used as the cathode current collector and a dry process is used to prepare the cathode sheet. The uncoated area of ​​the cathode sheet is then die-cut to form the cathode tab. The coated area of ​​the cathode sheet is a rectangle with a size of 60×50 mm.

[0099] The silicon anode, sulfide solid electrolyte (Li6PS5Cl), conductive agent (CNT), and binder (SEBS) are mixed in a mass ratio of 6:2:1:1 to obtain the raw materials for the anode material area. Then, copper foil is used as the anode current collector and a dry process is used to prepare the anode sheet. The uncoated area of ​​the anode sheet is then die-cut to form the anode tab. The coated area of ​​the anode sheet is a rectangle with a size of 62×52 mm. Finally, an insulating strip with a width of 1 mm is pasted on the circumferential edge of the coated area to fill the size difference between the positive and negative anode sheets.

[0100] The sulfide solid electrolyte (Li6PS5Cl) and binder (SEBS) were mixed at a mass ratio of 8:2 to obtain a mixture. Then, a sulfide solid electrolyte membrane was prepared by a dry process. The sulfide solid electrolyte membrane was a rectangle with dimensions of 64×54mm.

[0101] Eleven negative electrode sheets, eleven sulfide solid electrolyte membranes, and ten positive electrode sheets are stacked and pressed together. In the pressing process, a pressure of 10 MPa is applied for 200 s and the processing temperature is 60℃ to obtain a stacked cell with a specification of 10 positive and 11 negative electrodes, with the positive and negative electrode tabs located on the same side.

[0102] After the stacked cells are packaged, they are subjected to isostatic pressing to obtain an all-solid-state battery.

[0103] Test case (1) Open circuit voltage test: The all-solid-state batteries prepared in Examples 1-2 and Comparative Examples 1-3 were used as samples, and the open-circuit voltage of each sample was tested. The specific test steps for the open-circuit voltage were as follows: a multimeter was connected to the positive and negative terminals of the battery, the voltage values ​​were read, and the test results were summarized in Table 1.

[0104]

[0105] Referring to Table 1, the test results of Examples 1-2 and Comparative Examples 1-3 show that by using electrodes of the same shape and size and solid electrolyte membranes as the materials for preparing stacked cells, and by adding a cutting process to the edges of the non-tab area of ​​the cell after the pressing process, the prepared all-solid-state battery has the advantage of higher open-circuit voltage.

[0106] The test results of Examples 1 and 2 show that, compared with metal die cutting, the all-solid-state battery prepared by laser cutting has the advantage of higher open-circuit voltage.

[0107] (2) Cyclic performance test The all-solid-state batteries prepared in Example 1 and Comparative Example 3 were used as samples. The number of cycles in which the capacity of each sample decayed to 80% was counted. The specific test steps were as follows: the battery was placed at 25°C and the battery was subjected to 1C / 1C charge-discharge cycle test in the charge-discharge voltage range of 3.5 to 4.0 V until the ratio of the discharge capacity to the initial discharge capacity was less than 80%. The number of cycles of the battery was counted and the test results are summarized in Table 2.

[0108]

[0109] Referring to Table 2, the test results of Example 1 and Comparative Example 3 show that the all-solid-state battery prepared in this application has comparable cycle performance to that prepared by existing processes. This indicates that the technical solution of this application can increase the open-circuit voltage of the all-solid-state battery while maintaining its relatively excellent cycle performance (i.e., it will not suffer from severe lithium dendrite problems that would reduce the battery's cycle performance). In addition, it should be emphasized that compared with the comparative example (which requires more time to set the insulating filler strip), Example 1 also has the advantage of higher production efficiency.

[0110] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for preparing a laminated battery cell, characterized in that, Includes the following steps: The negative electrode, solid electrolyte membrane, and positive electrode are stacked and pressed together so that any adjacent negative electrode and positive electrode are separated by the solid electrolyte membrane. The coating area of ​​the negative electrode, the solid electrolyte membrane, and the coating area of ​​the positive electrode are all the same in shape and size, thus obtaining the cell precursor. Along the circumference of the cell precursor, at least a portion of the edge of the non-tab region of the cell precursor is cut to obtain a stacked cell.

2. The method for preparing a laminated battery cell according to claim 1, characterized in that, Along the circumference of the cell precursor, the edges of all regions of the non-tab area of ​​the cell precursor are cut.

3. The method for preparing a laminated battery cell according to claim 1 or 2, characterized in that, In the cutting process, the width of the cut area is 0.3~1.0 mm.

4. The method for preparing a laminated battery cell according to claim 1 or 2, characterized in that, In the cutting process, the cutting method is selected from at least one of laser cutting and metal die cutting.

5. The method for preparing a laminated battery cell according to claim 4, characterized in that, In the cutting process, the cutting method is laser cutting.

6. The method for preparing a laminated battery cell according to claim 5, characterized in that, During the laser cutting process, the laser power is 1~3 KW, or / and, and the cutting speed is 1~10 m / min.

7. The method for preparing a laminated battery cell according to claim 1 or 2, characterized in that, During the pressing process, at least one of the following conditions A to C must be met: A. Apply pressure of 1~20 MPa; B. The pressurization time is 10~600 s; C. The processing temperature is 50~100℃.

8. The method for preparing a laminated battery cell according to claim 1 or 2, characterized in that, The negative electrode tab in the negative electrode sheet has the same shape and size as the positive electrode tab in the positive electrode sheet.

9. The method for preparing a laminated battery cell according to claim 1 or 2, characterized in that, In the laminated cell, the number of positive electrode plates is N, and the number of negative electrode plates is N+1; Optionally, in the laminated cell, the number of positive electrode sheets is 5 to 15.

10. A laminated battery cell, characterized in that, It is prepared by the method of any one of claims 1 to 9.

11. An all-solid-state battery, characterized in that, Including the laminated battery cell as described in claim 10.

12. An electrical appliance, characterized in that, Including the all-solid-state battery as described in claim 11.

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