A solid-state battery and a method for manufacturing the same

Abstract

The present invention discloses a solid-state battery and a method for making the same, comprising a cylindrical support, an inner cylindrical shell, a wound stack, an outer cylindrical shell, and positive and negative terminals, wherein the cylindrical support is located inside the inner cylindrical shell, the wound stack is located between the inner cylindrical shell and the outer cylindrical shell, the positive and negative terminals are located at both ends of the wound stack, and the wound stack comprises a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked in sequence. The solid-state battery is cylindrical in shape, fully combining the structural advantages of the cylindrical shell, and can provide all-round uniform pressurization for the internal winding stack. The solid-state battery is internally self-pressurized by the internal cylindrical support, and no additional pressurization device is required to be added to the outside of the battery cell, which can simplify the battery pack structure, and has good compatibility with the mature process of traditional cylindrical batteries, and has manufacturing advantages such as high production capacity and high degree of automation, and is easy to achieve large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state battery materials, and in particular to a solid-state battery and a method for manufacturing the same. Background Art

[0002] The development of electric vehicles and next-generation electronic devices has put forward higher requirements for battery systems. In addition to meeting the requirements of high energy density and long cycle life, safety performance is also one of the factors that cannot be ignored. However, the organic electrolytes commonly used in lithium-ion batteries currently have safety hazards such as flammability and leakage. The use of highly safe solid electrolytes to replace liquid electrolytes is expected to fundamentally solve this problem. Therefore, all-solid-state batteries based on solid electrolytes are strong competitors for the next generation of energy storage devices. However, since the contact between the electrolyte and the electrode of solid-state batteries is solid-solid contact, the interface contact performance is poor. As the battery continues to cycle, the repeated changes in the electrode volume will cause the contact between the electrolyte and the active material particles to deteriorate, resulting in increased interface resistance and capacity loss. Usually, high voltage is required to meet normal charging and discharging, which seriously limits the practical application of solid-state batteries. Summary of the invention

[0003] The purpose of the present invention is to provide a solid-state battery and a method for manufacturing the same, so as to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0004] The technical solutions adopted to solve the above technical problems are:

[0005] The present invention provides a solid-state battery, comprising a cylindrical support body, an inner cylindrical shell, a wound stack body, an outer cylindrical shell, and positive and negative terminals. The cylindrical support body is located inside the inner cylindrical shell, the wound stack body is located between the inner cylindrical shell and the outer cylindrical shell, the positive and negative terminals are located at both ends of the wound stack body, and the wound stack body comprises a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked in sequence.

[0006] The beneficial effects of the present invention are:

[0007] The solid-state battery of the present invention is cylindrical in shape, which fully combines the structural advantages of the cylindrical shell. It can provide all-round uniform pressurization for the internal winding and stacking. The solid-state battery is self-pressurized internally through the internal cylindrical support body. There is no need to add additional pressurizing devices to the outside of the battery cell, which can simplify the battery pack structure. It also has good compatibility with the mature process of traditional cylindrical battery cells, has manufacturing advantages such as high production capacity and high degree of automation, and is easy to achieve large-scale production.

[0008] As a further improvement of the above technical solution, the positive electrode layer and the negative electrode layer both include a current collector layer and an active material layer, and the electrolyte layer is located between the active material layers in the positive electrode layer and the negative electrode layer, wherein the electrolyte layer width ≥ the negative electrode layer width > the positive electrode layer width, which can prevent short circuit of the solid-state battery and improve the safety of the solid-state battery.

[0009] As a further improvement of the above technical solution, the wound stack includes a sulfide electrolyte, the sulfide is Li3PS4, Li4P2S6 or Li7-aPS6-aYa, wherein Y is at least one of Cl, Br, and I, and a is 0.5 to 2. Since the sulfur-based solid electrolyte material is relatively soft, it can be well adhered to the surface of the positive and negative electrodes under pressure, thereby reducing the interface contact impedance.

[0010] As a further improvement of the above technical solution, the inner cylindrical shell and the outer cylindrical shell are both provided with roller grooves near the two ends of their corresponding shells, and the inner cylindrical shell is turned outward at the contact with the positive and negative terminals, and the outer cylindrical shell is turned inward at the contact with the positive and negative terminals, so as to seal the wound stack in a snap-fit ​​manner. The roller grooves are provided to facilitate pressurization of the two ends of the cylindrical battery cell, so that the two ends of the winding stack are more closely fitted with the positive and negative terminals, thereby enhancing electrical contact.

[0011] As a further improvement of the above technical solution, the thickness of the inner cylindrical shell is ≤ the thickness of the outer cylindrical shell, and the tensile strength of the inner cylindrical shell is greater than the tensile strength of the outer cylindrical shell. In order to ensure that when the cylindrical support body is inserted into the inner cylindrical shell, the wound stacked body is pressurized by the better stretching of the inner cylindrical shell, and the wound stacked body is maintained under pressure by the poor stretching of the outer cylindrical shell.

[0012] As a further improvement of the above technical solution, the positive and negative terminals are annular metal sheets, whose inner ring diameter is ≥ the inner cylindrical shell diameter, and whose outer ring diameter is ≤ the outer cylindrical shell diameter, to ensure that the positive and negative terminals can enter the shell for electrical connection, and the inner and outer rings of the ring can optionally be coated with glue to better ensure the sealing.

[0013] As a further improvement of the above technical solution, the compressive strength of the cylindrical support body is greater than the tensile strength of the inner cylindrical shell, ensuring that the internal wound stack can be pressurized by extruding the inner cylindrical shell; the height of the cylindrical support body is greater than the width of the positive electrode layer and less than the height of the inner cylindrical shell, ensuring that the positive electrode active material layer can be fully extruded.

[0014] As a further improvement of the above technical solution, an insulating layer needs to be provided on the surface of the cylindrical support body to avoid short circuit caused by connecting the positive and negative terminals of the cylinder.

[0015] The present invention also provides a method for manufacturing a solid-state battery, comprising: preparing a composite positive electrode sheet;

[0016] preparing a composite negative electrode sheet;

[0017] Winding: Paste one end of the composite positive electrode sheet and the composite negative electrode sheet on the inner cylindrical shell, apply a certain tension to wind them to prepare a winding stack and perform high-pressure densification;

[0018] Assembly: Place the high-voltage densified wound stack inside the outer cylindrical shell, perform roller groove processing on the outer cylindrical shell, and fix the internal wound stack; insert the cylindrical support into the inner cylindrical shell by extrusion; then vertically extrude the positive and negative terminals, shape the cylindrical battery cell, and obtain a finished all-solid-state cylindrical battery cell.

[0019] This manufacturing method fully combines the structural advantages of the outer cylindrical shell and the inner cylindrical shell, can provide all-round uniform pressurization for the internal winding stack, and can perform internal self-pressurization of the solid-state battery through the internal cylindrical support body. There is no need to add additional pressurization devices to the outside of the battery cell, which can simplify the battery pack structure.

[0020] As a further improvement of the above technical solution, the positive electrode active material, the conductive agent, the electrolyte and the binder are uniformly mixed and then coated on the current collector;

[0021] Sintering the current collector and the coating material at 500-800° C. under an inert gas to form a coating layer 1;

[0022] An electrolyte layer is coated on the coating layer 1 to form a coating layer 2;

[0023] The coating layer 2 is rolled and compacted to obtain a composite positive electrode sheet;

[0024] The step of preparing the composite negative electrode sheet includes: adjusting the manufacturing material to the composite negative electrode sheet manufacturing material, and the preparation step is the same as the step of preparing the composite positive and negative electrode layer.

[0025] Experimental comparison shows that the capacity retention rate of solid-state batteries produced by this production method is significantly higher than that of solid-state batteries produced by ordinary methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0027] Figure 1 is a cross-sectional view of an embodiment of a solid-state battery provided by the present invention;

[0028] Figure 2 yes Figure 1 A partial enlarged view of the upper end of the solid-state battery;

[0029] Figure 3 This is a structural diagram of an embodiment of a solid-state battery provided by the present invention;

[0030] Figure 4 This is a solid-state battery provided by the present invention, and a structural diagram of one embodiment thereof during winding;

[0031] Figure 5 This is a method for manufacturing a solid-state battery provided by the present invention, and a flow chart of one embodiment thereof;

[0032] Figure 6 A method for manufacturing a solid-state battery provided by the present invention is a flow chart of manufacturing a positive electrode sheet in one embodiment;

[0033] Figure 7 This is a method for manufacturing a solid-state battery provided by the present invention, and a flow chart of manufacturing a negative electrode sheet in one embodiment;

[0034] Figure 8 A method for manufacturing a solid-state battery provided by the present invention is provided, and a performance test cycle retention result diagram of the finished battery cells prepared in an embodiment and a comparative example is performed.

[0035] Reference numerals:

[0036] The cylindrical support 100 , the inner cylindrical shell 200 , the roller groove 210 , the wound stack 300 , the positive electrode layer 310 , the electrolyte layer 320 , the negative electrode layer 330 , the outer cylindrical shell 400 , and the positive and negative electrode terminals 500 . DETAILED DESCRIPTION

[0037] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0038] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, if there are words such as "several", it means one or more, "more" means more than two, greater than, less than, exceed, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0040] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0041] The development of electric vehicles and next-generation electronic devices has put forward higher requirements for battery systems. In addition to meeting the requirements of high energy density and long cycle life, safety performance is also one of the factors that cannot be ignored. However, the organic electrolytes commonly used in lithium-ion batteries currently have safety hazards such as flammability and leakage. The use of highly safe solid electrolytes to replace liquid electrolytes is expected to fundamentally solve this problem. Therefore, all-solid-state batteries based on solid electrolytes are strong competitors for the next generation of energy storage devices. However, since the contact between the electrolyte and the electrode of solid-state batteries is solid-solid contact, the interface contact performance is poor. As the battery continues to cycle, the repeated changes in the electrode volume will cause the contact between the electrolyte and the active material particles to deteriorate, resulting in increased interface resistance and capacity loss. Usually, high voltage is required to meet normal charging and discharging, which seriously limits the practical application of solid-state batteries.

[0042] Therefore, refer to Figures 1 to 8 The present invention provides a solid-state battery and a method for manufacturing the same, and makes the following embodiments, which can self-pressurize the battery cells of the solid-state battery without the need for additional pressurization of the battery cells of the solid-state battery.

[0043] In some embodiments, a solid-state battery is cylindrical as a whole, and includes a wound stack 300, an inner cylindrical shell 200, an outer cylindrical shell 400, positive and negative terminals 500, and a cylindrical support 100. The wound stack 300 is wound around the outer circumferential wall of the inner cylindrical shell 200, and the outer cylindrical shell 400 is arranged on the outer circumferential wall of the wound stack 300, that is, the wound stack 300 is located between the inner cylindrical shell 200 and the outer cylindrical shell 400, the positive and negative terminals 500 are located at both ends of the wound stack 300, and the cylindrical support 100 is located inside the inner cylindrical shell 200.

[0044] Compared with the cylindrical structure with an elliptical cross-section, the cylindrical battery structure has the characteristic of uniform pressurization performance. Because the elliptical shape causes different parts of the shell to have different radii of curvature. When pressure is evenly applied to the elliptical shell, the pressure distribution on various parts of the shell may be uneven due to the difference in the radius of curvature. This uneven pressure distribution may cause certain areas to be subjected to excessive stress, thereby increasing the risk of shell failure. Therefore, the solid-state battery of the present invention is cylindrical in shape, fully combining the structural advantages of the cylindrical shell, and can provide all-round uniform pressurization for the internal winding stack. The solid-state battery is internally self-pressurized by the internal cylindrical support body 100. There is no need to add an additional pressurization device to the outside of the battery cell, which can simplify the battery pack structure, and has good compatibility with the mature process of traditional cylindrical batteries. It has manufacturing advantages such as high production capacity and high degree of automation, and is easy to achieve large-scale production.

[0045] The aforementioned wound stack 300 comprises a positive electrode layer 310, a negative electrode layer 330, and an electrolyte layer 320, wherein the positive electrode layer 310 and the negative electrode layer 330 comprise a current collector layer and an active material layer, and the electrolyte layer 320 is located between the positive and negative active material layers, wherein the width of the electrolyte layer 320 ≥ the width of the negative electrode layer 330 > the width of the positive electrode layer 310, which can prevent the short circuit of the solid-state battery and improve the safety of the solid-state battery. The current collector layer has a collector composed of a metal foil material, and the metal foil material can be selected from one of aluminum, copper, nickel, iron, and stainless steel. The positive current collector layer is preferably aluminum, and the negative current collector layer is preferably copper. It should be noted that the width referred to in this embodiment corresponds to the height of the cylindrical support 100 in the accompanying drawings.

[0046] The electrolyte in the aforementioned wound stack 300 is a sulfide electrolyte, and the sulfide is Li3PS4, Li4P2S6 or Li7-aPS6-aYa, wherein Y is at least one of Cl, Br, and I, and a is 0.5 to 2. Since the sulfur-based solid electrolyte material is relatively soft, it can be well adhered to the surface of the positive and negative electrodes under pressure, thereby reducing the interface contact impedance.

[0047] In the aforementioned solid-state battery, the inner cylindrical shell 200 and the outer cylindrical shell 400 are made of stainless steel or aluminum, and there are roller grooves 210 near the two ends of the shell. The inner cylindrical shell 200 is turned outward at the contact with the positive and negative terminals 500, and the outer cylindrical shell 400 is turned inward at the contact with the positive and negative terminals 500, so as to seal the wound stack 300 in a snap-fit ​​manner. The roller grooves 210 are provided to facilitate pressurization of the two ends of the cylindrical battery cell, so that the two ends of the winding stack 300 are more closely fitted with the positive and negative terminals 500, thereby enhancing electrical contact.

[0048] In the aforementioned cylindrical shell, the thickness of the inner cylindrical shell 200 is ≤ the thickness of the outer cylindrical shell 400, and the tensile strength of the inner cylindrical shell 200 is greater than the tensile strength of the outer cylindrical shell 400. In order to ensure that when the cylindrical support body 100 is inserted into the inner cylindrical shell 200, the wound stack 300 is pressurized by the better stretching of the inner cylindrical shell 200, and the wound stack 300 is maintained under pressure by the poor stretching of the outer cylindrical shell 400.

[0049] The positive and negative terminals 500 are annular metal sheets, the inner ring diameter of which is ≥ the inner cylindrical shell 200 diameter, and the outer ring diameter is ≤ the outer cylindrical shell 400 diameter, to ensure that the positive and negative terminals 500 can be inserted into the shell for electrical connection. The inner and outer rings of the ring can be optionally coated with glue to better ensure the sealing. The material of the positive and negative terminals 500 can be selected from aluminum, copper, nickel, nickel-plated copper, iron, and stainless steel. The positive terminal is preferably aluminum, and the negative terminal is preferably nickel-plated copper.

[0050] The aforementioned positive and negative terminals 500 are welded by laser welding. The tabs of the wound stack 300 are directly electrically connected to the positive and negative terminals 500. The welding method is preferably laser welding and ultrasonic welding. The welding appearance is preferably linear welding, and the effective welding area is larger.

[0051] The aforementioned cylindrical support body 100 is a solid body or a honeycomb hollow body, and its compressive strength is greater than the tensile strength of the inner cylindrical shell 200, ensuring that the internal wound stack 300 can be pressurized by extruding the inner cylindrical shell 200; the height of the cylindrical support body 100 is greater than the width of the positive electrode layer 310 and less than the height of the inner cylindrical shell 200, ensuring that the positive electrode active material layer can be fully extruded; an insulating layer needs to be configured on the surface of the cylindrical support body 100 to avoid short circuit caused by the cylinder connecting the positive and negative terminals 500.

[0052] Reference Figure 5 The present invention also provides a method for manufacturing a solid-state battery, comprising:

[0053] S100: preparing a composite positive electrode sheet;

[0054] S200: preparing a composite negative electrode sheet;

[0055] S300: Winding, pasting one end of the composite positive electrode sheet and the composite negative electrode sheet on the inner cylindrical shell 200, applying a certain tension to wind them to prepare a winding stack and perform high-pressure densification;

[0056] S400: assembly, wherein S400 also includes S410, S420, and S430;

[0057] S410: placing the high-pressure densified winding stack inside the outer cylindrical shell 400, performing roller groove 210 processing on the outer cylindrical shell 400, and fixing the internal winding stack;

[0058] S420: inserting the cylindrical support body 100 into the inner cylindrical shell 200 by extrusion;

[0059] S430: vertically extrude the positive and negative terminals 500, and shape the cylindrical battery cell to obtain a finished all-solid cylindrical battery cell.

[0060] This manufacturing method fully combines the structural advantages of the outer cylindrical shell 400 and the inner cylindrical shell 200, and can provide all-round uniform pressurization for the internal winding stack. The solid-state battery is self-pressurized internally through the internal cylindrical support body 100. There is no need to add additional pressurization devices to the outside of the battery cell, which can simplify the battery pack structure.

[0061] Reference Figure 6 , where S100 also includes:

[0062] S110: uniformly mixing the positive electrode active material, the conductive agent, the electrolyte and the binder, and applying the mixture on the current collector;

[0063] S120: sintering the current collector and the coating material at 500-800° C. under an inert gas to form a coating layer 1;

[0064] S130: coating the electrolyte layer 320 on the coating layer 1 to form the coating layer 2;

[0065] S140: rolling and compacting the coating layer 2 to obtain a composite positive electrode sheet;

[0066] Reference Figure 7 , where S200 also includes:

[0067] S210: uniformly mixing the negative electrode active material, the conductive agent, the electrolyte and the binder, and applying the mixture on the current collector;

[0068] S220: sintering the current collector and the coating material at 500-800° C. under an inert gas to form a coating layer 1;

[0069] S2130: coating the electrolyte layer 320 on the coating layer 1 to form the coating layer 2;

[0070] S240: rolling and compacting the coating layer 2 to obtain a composite positive electrode sheet;

[0071] When making the negative electrode sheet, the making material is adjusted to the composite negative electrode sheet making material, and the preparation steps are the same as the steps for preparing the composite positive and negative electrode layers.

[0072] refer to Figure 8 Through experimental comparison, it can be concluded that the capacity retention rate of the solid-state battery produced by this production method is significantly higher than that of the solid-state battery produced by ordinary methods.

[0073] Example 1

[0074] Preparation of positive electrode sheet: Active material slurry for forming coating layer 1 and electrolyte slurry for forming coating layer 2 are prepared respectively; wherein the active material slurry ratio of coating layer 1 is NCM (811): Li6PS5Cl electrolyte: VGCF: SEBS = 90: 10: 2: 1, SEBS is added in the form of glue, and the solid content is 7%. First, the weighed NCM (811), Li6PS5Cl electrolyte and VGCF are pre-mixed, and then the solvent p-xylene is added to adjust the solid content to about 70% and kneading is started. After kneading and dispersion, SEBS glue is added to continue mixing and dispersing to form the slurry to be coated. After the slurry is coated on both sides of the 8um carbon-coated copper foil by a scraper, it is vacuum dried at 60℃ for 2h, and then taken out and fired at 500℃ for 2h in N2 atmosphere to obtain coating layer 1. The electrolyte slurry ratio of coating layer 2 is Li6PS5Cl electrolyte: SEBS = 99: 1, SEBS is added in the form of glue, and the solid content is 7%. First, add the weighed Li6PS5Cl electrolyte to the solvent p-xylene to adjust the solid content to about 60% and start kneading. After kneading and dispersion, add SEBS glue and continue mixing and dispersing to form the slurry to be coated. Apply the slurry on the coating layer 1 with a scraper, dry it in vacuum at 60°C for 2h, and roll it to obtain a composite positive electrode sheet. After rolling, the porosity of the electrode sheet is controlled to be below 20%.

[0075] Preparation of negative electrode sheet: Active material slurry for forming coating layer 1 and electrolyte slurry for forming coating layer 2 are respectively prepared; wherein the active material slurry ratio of coating layer 1 is graphite: Li6PS5Cl electrolyte: VGCF: SEBS = 80: 20: 2: 1, SEBS is added in the form of glue, and the solid content is 7%. First, the weighed graphite, Li6PS5Cl electrolyte and VGCF are pre-mixed, and then solvent p-xylene is added to adjust the solid content to about 60% and kneading is started. After kneading and dispersion, SEBS glue is added to continue mixing and dispersing to form the slurry to be coated. After the slurry is coated on both sides of the 13um carbon-coated aluminum foil by a scraper, it is vacuum dried at 60°C for 2h, and then taken out and fired at 500°C for 2h in N2 atmosphere to obtain coating layer 1. The electrolyte slurry ratio of coating layer 2 is Li6PS5Cl electrolyte: SEBS = 99: 1, SEBS is added in the form of glue, and the solid content is 7%. First, add the weighed Li6PS5Cl electrolyte to the solvent p-xylene to adjust the solid content to about 60% and start kneading. After kneading and dispersion, add SEBS glue and continue mixing and dispersing to form the slurry to be coated. Apply the slurry on the coating layer 1 with a scraper, dry it in vacuum at 60°C for 2h, and roll to obtain a composite negative electrode sheet. After rolling, the porosity of the electrode sheet is controlled to be below 20%.

[0076] Winding: Paste one end of the composite positive and negative electrode sheets on the inner cylindrical shell 200 and apply a certain tension to wind them to prepare a winding stack. Paste a circle of expansion tape at the end of the winding to obtain a winding stack.

[0077] High-pressure densification: The wound stack is sealed in an aluminum-plastic film and subjected to high-pressure densification inside an isostatic press.

[0078] Assembly: The high-pressure densified winding stack is placed inside the outer cylindrical shell 400, the outer cylindrical shell 400 is subjected to roller groove 210 treatment, the internal winding stack is fixed, and the tabs at both ends of the stack are laser welded to the positive and negative terminals 500. Then the positive and negative terminals 500 are placed inside the outer cylindrical shell 400 for snap-on sealing.

[0079] Cylindrical support body 100: The PPK material cylindrical support body 100 is inserted into the inner cylindrical shell 200 by extrusion, and then the positive and negative terminals 500 are vertically extruded to shape the cylindrical battery cell, and finally a finished all-solid cylindrical battery cell is obtained.

[0080] Comparative Example 1

[0081] Preparation of positive electrode sheet: first prepare active material slurry; the slurry ratio is NCM (811): Li6PS5Cl electrolyte: VGCF: SEBS = 85:15:2:1, SEBS is added in the form of glue, and the solid content is 7%. First, the weighed NCM (811), Li6PS5Cl electrolyte and VGCF are pre-mixed, and then the solvent p-xylene is added to adjust the solid content to about 70% and kneading begins. After kneading and dispersion, SEBS glue is added to continue mixing and dispersing to form the slurry to be coated. After the slurry is coated on both sides of the 8um thick carbon-coated copper foil with a scraper, it is vacuum dried at 60°C for 2h to obtain the positive electrode sheet.

[0082] Preparation of negative electrode sheet: First, prepare the active material slurry; the slurry ratio is graphite: Li6PS5Cl electrolyte: VGCF: SEBS = 70:30:2:1, SEBS is added in the form of glue, and the solid content is 7%. First, the weighed graphite, Li6PS5Cl electrolyte and VGCF are pre-mixed, and then the solvent p-xylene is added to adjust the solid content to about 60% and kneading begins. After kneading and dispersion, SEBS glue is added to continue mixing and dispersing to form the slurry to be coated. After the slurry is coated on both sides of the 13um carbon-coated aluminum foil with a scraper, it is vacuum dried at 60°C for 2h to obtain the negative electrode sheet.

[0083] Preparation of electrolyte sheet: First, prepare electrolyte slurry; the slurry ratio is Li6PS5Cl electrolyte: SEBS = 99:1, SEBS is added in the form of glue, and the solid content is 7%. First, add the weighed Li6PS5Cl electrolyte to the solvent p-xylene to adjust the solid content to about 60% and start kneading. After kneading and dispersion, add SEBS glue and continue mixing and dispersing to form the slurry to be coated. Apply the slurry on the PET film with a scraper and vacuum dry at 60°C for 2h to obtain the electrolyte sheet.

[0084] Preparation of composite positive electrode sheet: The electrolyte sheet coated on the PET film and the positive electrode sheet are composited, and the electrolyte sheet is transferred to the positive electrode sheet under 70° C. hot roller pressing to obtain a composite positive electrode sheet.

[0085] Preparation of composite negative electrode sheet: The electrolyte sheet coated on the PET film and the negative electrode sheet are composited, and the electrolyte sheet is transferred to the negative electrode sheet under 70° C. hot roller pressing to obtain a composite negative electrode sheet.

[0086] Winding: Paste one end of the composite positive and negative electrode sheets on the inner cylindrical shell 200 and apply a certain tension to wind them to prepare a winding stack. Paste a circle of expansion tape at the end of the winding to obtain a winding stack.

[0087] High-pressure densification: The wound stack is sealed in an aluminum-plastic film and subjected to high-pressure densification inside an isostatic press.

[0088] Assembly: The high-pressure densified winding stack is placed inside the outer cylindrical shell 400, the outer cylindrical shell 400 is subjected to roller groove 210 treatment, the internal winding stack is fixed, and the pole ears at both ends of the stack are laser welded to the positive and negative terminals 500. After that, the positive and negative terminals 500 are placed inside the outer cylindrical shell 400 for snap-on sealing, and then the positive and negative terminals 500 are vertically extruded to shape the cylindrical battery cell, and finally a finished all-solid cylindrical battery cell is obtained.

[0089] Performance test: The finished battery cells prepared in the above embodiments and comparative examples were subjected to performance tests. The cycle retention rate results are shown in FIG. Figure 8 As shown. Figure 8 It can be clearly seen from the data that the cycle retention rate of the battery cell prepared in Example 1 is significantly improved.

[0090] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A solid-state battery, characterized in that: It includes a cylindrical support body, an inner cylindrical shell, a wound stack body, an outer cylindrical shell, and positive and negative terminals. The cylindrical support body is located inside the inner cylindrical shell, the wound stack body is located between the inner cylindrical shell and the outer cylindrical shell, the positive and negative terminals are located at both ends of the wound stack body, the wound stack body includes a positive electrode layer, an electrolyte layer, and a negative electrode layer stacked in sequence, the cylindrical support body is a solid body or a honeycomb hollow body, and the cylindrical support body pressurizes the internal wound stack body by squeezing the inner cylindrical shell to meet the solid-state battery's need for high pressure to meet normal charging and discharging requirements.

2. A solid-state battery according to claim 1, characterized in that: The positive electrode layer and the negative electrode layer both include a current collector layer and an active material layer, and the electrolyte layer is located between the active material layers in the positive electrode layer and the negative electrode layer, wherein the width of the electrolyte layer ≥ the width of the negative electrode layer > the width of the positive electrode layer.

3. A solid-state battery according to claim 1, characterized in that: The wound stack includes a sulfide electrolyte, the sulfide is Li3PS4, Li4P2S6 or Li7-aPS6-aYa, wherein Y is at least one of Cl, Br, and I, and the value of a is 0.5~2.

4. A solid-state battery according to claim 1, characterized in that: The inner cylindrical shell and the outer cylindrical shell are both provided with roller grooves near the two ends of their corresponding shells. The inner cylindrical shell is turned outward at the contact with the positive and negative terminals, and the outer cylindrical shell is turned inward at the contact with the positive and negative terminals.

5. A solid-state battery according to claim 1, characterized in that: The thickness of the inner cylindrical shell is less than or equal to the thickness of the outer cylindrical shell, and the tensile strength of the inner cylindrical shell is greater than the tensile strength of the outer cylindrical shell.

6. A solid-state battery according to claim 1, characterized in that: The positive and negative terminals are annular metal sheets, the inner ring diameter of which is greater than or equal to the inner cylindrical shell diameter, and the outer ring diameter of which is less than or equal to the outer cylindrical shell diameter.

7. A solid-state battery according to claim 1, characterized in that: The compressive strength of the cylindrical support body is greater than the tensile strength of the inner cylindrical shell; the height of the cylindrical support body is greater than the width of the positive electrode layer and less than the height of the inner cylindrical shell.

8. A solid-state battery according to claim 7, characterized in that: An insulating layer needs to be provided on the surface of the cylindrical support.

9. A method for manufacturing a solid-state battery, used to manufacture the solid-state battery according to any one of claims 1 to 8, characterized in that: preparing a composite positive electrode sheet; preparing a composite negative electrode sheet; Winding: Paste one end of the composite positive electrode sheet and the composite negative electrode sheet on the inner cylindrical shell, apply a certain tension to wind them to prepare a winding stack and perform high-pressure densification; Assembly: Place the high-voltage densified wound stack inside the outer cylindrical shell, perform roller groove processing on the outer cylindrical shell, fix the internal wound stack, insert the cylindrical support into the inner cylindrical shell by extrusion, and then vertically extrude the positive and negative terminals to shape the cylindrical battery cell to obtain a finished all-solid-state cylindrical battery cell.

10. The method for manufacturing a solid-state battery according to claim 9, characterized in that: The steps of preparing the composite positive electrode sheet include: The positive electrode active material, the conductive agent, the electrolyte and the binder are uniformly mixed and then coated on the current collector; Sintering the current collector and the coating material at 500-800° C. under an inert gas to form a coating layer 1; An electrolyte layer is coated on the coating layer 1 to form a coating layer 2; The coating layer 2 is rolled and compacted to obtain a composite positive electrode sheet; The step of preparing the composite negative electrode sheet includes: adjusting the manufacturing material to the composite negative electrode sheet manufacturing material, and the preparation step is the same as the step of preparing the composite positive and negative electrode layer.

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