Solid-state battery short circuit protection methods and solid-state batteries

Abstract

This invention belongs to the field of solid-state battery technology, specifically relating to a short-circuit protection method for solid-state batteries and a solid-state battery. The method includes the following steps: Step 1: Providing a composite electrode sheet, which is formed by transferring a negative electrode sheet and a solid electrolyte membrane; Step 2: Adhering insulating tape to the edge of the composite electrode sheet; Step 3: Applying adhesive to the upper surfaces of the first, second, third, and fourth adhesive tapes along the edge of the composite electrode sheet to form adhesive lines, and then UV curing the adhesive lines; Step 4: Providing a positive electrode sheet, and alternately stacking the positive electrode sheet with the composite electrode sheet processed in steps 1 to 3 to form a battery cell; Step 5: Encapsulating and isostatically pressing the stacked battery cell. Using this method, the short-circuit rate of a large-capacity solid-state battery after isostatic pressing is significantly reduced from 90% to 0.2%, achieving the same reliability level as liquid batteries, and significantly improving the manufacturing yield and engineering feasibility of solid-state batteries.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a short-circuit protection method for solid-state batteries and a solid-state battery. Background Technology

[0002] Solid-state batteries are considered a key development direction for next-generation electrochemical energy storage devices due to their high energy density and potential for high safety. In the engineering manufacturing process of solid-state batteries, to address the problem of high contact impedance at the solid-solid interface, isostatic pressing is typically used to apply extremely high pressure to the stacked cells to improve interface adhesion. However, isostatic pressing also brings new challenges, with "short circuit after isostatic pressing of the electrode assembly" becoming a key bottleneck restricting its mass production.

[0003] To address this issue, existing technologies primarily employ insulation treatment at the edge of the negative electrode. For example, insulating adhesive is applied to the edge of the negative electrode using screen printing or dispensing processes, and then cured with ultraviolet (UV) light to form an adhesive line. This mitigates the risk of short circuits caused by the negative electrode collapsing during isostatic pressing due to the "positive electrode size being smaller than the negative electrode size" resulting from safety design considerations.

[0004] Patent document CN223638395U discloses a short-circuit-proof all-solid-state battery, which achieves short-circuit protection by setting a hollow quadrilateral insulating frame layer between the positive and negative electrode plates. After stacking and pressurizing, the insulating frame layer is embedded or partially embedded in the adjacent solid electrolyte layer.

[0005] The patent document with publication number CN119627241A discloses a method for manufacturing solid-state battery cells based on single-sided frame molding. This method uses a molding process to manufacture a frame on both sides of one of the positive or negative electrode sheets, so that the other electrode sheet is embedded in the frame. The frame's enclosure and limiting effect restricts the lateral displacement between the electrodes, ensuring a tight fit between the solid electrolyte layer and the electrode sheet.

[0006] Patent document CN120809911A discloses a prefabricated adhesive frame, which includes a laminated adhesive sheet and a composite sheet. After the sheet is peeled off by an easy-tear structure, the frame is glued to the negative electrode sheet, so that the positive electrode sheet can be placed inside, thereby avoiding the toxic gases that may be generated by direct adhesive curing.

[0007] However, the aforementioned existing technologies still have shortcomings in practical applications. Specifically, the adhesive lines formed by direct application of adhesive (dispensing or screen printing) often have an approximately arc-shaped cross-section. Under the support of ultra-high pressure during isostatic pressing, the contact area at the apex of the adhesive line will generate a peak force. This peak pressure acts directly on the negative electrode sheet, easily causing the electrolyte layer on its surface to detach, thus creating a new short-circuit risk point. At the same time, the precision of the screen printing process is highly dependent on the screen tension, squeegee pressure, and the viscosity stability of the paste. In large-scale production, process control is difficult, and the screen is easily damaged, resulting in low material utilization and poor economic efficiency. Furthermore, neither dispensing nor screen printing can reliably solve the short-circuit risk at the contact area between the edge of the positive electrode sheet and the negative electrode sheet. More importantly, the aforementioned existing technologies have failed to effectively solve the core problem of interlayer collapse and deformation of adjacent negative electrode sheets caused by the "overhang" design of the positive and negative electrode sheets (the negative electrode size is larger than the positive electrode size) during isostatic pressing, which leads to the electrolyte membrane detaching under shear force and short-circuiting into the positive electrode foil. Summary of the Invention

[0008] The purpose of this invention is to provide a short-circuit protection method for solid-state batteries and a solid-state battery, which can effectively reduce the short-circuit rate after isostatic pressing, avoid the problem of mutual solubility between insulating materials and electrodes, and is easy to implement in engineering.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a short-circuit protection method for solid-state batteries, comprising the following steps: Step 1: Provide a composite electrode sheet, which is formed by transferring a negative electrode sheet and a solid electrolyte membrane; Step 2: Adhere insulating tape to the edge of the composite electrode, including: A first adhesive tape is pasted on the short side of the non-tab side of the composite electrode. The first adhesive tape is U-shaped and covers both the front and back sides of the composite electrode and is attached to the short side end face. A second adhesive tape and a third adhesive tape are respectively pasted on the first long side and the second long side of the composite electrode, and the second adhesive tape and the third adhesive tape are each pasted on both the front and back sides of the composite electrode. A fourth adhesive tape is pasted onto the short side of the tab side of the composite electrode sheet; Step 3: Apply adhesive to the upper surfaces of the first adhesive tape, the second adhesive tape, the third adhesive tape, and the fourth adhesive tape, along the edge of the composite electrode to form an adhesive line, and then UV cure the adhesive line; Step 4: Provide a positive electrode sheet, and alternately stack the positive electrode sheet with the composite electrode sheet processed in steps 1 to 3 to form a battery cell. When stacking, the edge of the positive electrode sheet is pressed against the upper surface of the insulating adhesive paper, and the edge of the positive electrode sheet does not extend beyond the upper surface of the adhesive line. Step 5: Package and isostatically pressurize the stacked cells.

[0010] Preferably, the first adhesive paper, the second adhesive paper, the third adhesive paper and the fourth adhesive paper are all PI adhesive paper, the adhesive liquid is silicone, the thickness δ is 5μm≤δ≤16μm, and the adhesion is 150~200g / 10mm.

[0011] Preferably, the width W1 of the composite electrode covered by the first and fourth adhesive tapes satisfies: W1>(L×λ1) / 2+△1, where L is the designed length of the composite electrode, λ1 is the shrinkage rate in the length direction of the electrode after isostatic pressing, and △1 is the cumulative tolerance of the electrode's own tolerance and the stacking alignment deviation; the width W2 of the composite electrode covered by the second and third adhesive tapes satisfies: W2>(W×λ2) / 2+△1, where W is the designed width of the composite electrode, and λ2 is the shrinkage rate in the width direction of the electrode after isostatic pressing.

[0012] Preferably, a gap d is left at the junction of the second adhesive tape, the third adhesive tape, the fourth adhesive tape, and the first adhesive tape, and 0≤d≤0.5mm.

[0013] Preferably, the adhesive line in step three includes a first adhesive line located in the non-thinning area and a second adhesive line located in the thinning area on the tab side; the adhesive used for the adhesive line is pure UV silicone, modified UV silicone, or acrylate UV adhesive, with a viscosity range of 80000mPa·s≤P≤130000mPa·s, and the distance d3 between the adhesive line and the edge of the insulating adhesive paper is ≤0.2mm.

[0014] Preferably, the thickness t1 of the first adhesive line and the thickness t2 of the second adhesive line are set according to the following formulas: t1 = h - δ - λ3 - h×5%; t2 = h - δ - λ3 - h×5% + h×24.5%; Where h is the thickness of the positive electrode sheet, δ is the thickness of the insulating paper, and λ3 is the compression ratio in the thickness direction of the positive electrode sheet under isostatic pressing.

[0015] Preferably, in step four, the single-sided overhang dimension of the positive electrode sheet and the composite electrode sheet is 1.5~3mm, and the width of the area where the edge of the positive electrode sheet presses against the surface of the insulating adhesive paper during stacking is 1.5~3mm.

[0016] The present invention also discloses a solid-state battery prepared by the method described above, comprising an aluminum-plastic film casing and a stacked electrode assembly. The electrode assembly includes a positive electrode and a composite electrode. A U-shaped first adhesive tape covering both sides is pasted on the short side of the non-tab side of the composite electrode. A second adhesive tape and a third adhesive tape are pasted on the first and second long sides of the composite electrode, respectively, on both sides. A fourth adhesive tape is pasted on the short side of the tab side of the composite electrode. A UV-curable adhesive line is provided on the upper surface of the first, second, third, and fourth adhesive tapes. The edge of the positive electrode is pressed against the upper surface of the insulating adhesive tape and does not extend beyond the upper surface of the adhesive line.

[0017] Preferably, the thickness δ of the first adhesive tape, the second adhesive tape, the third adhesive tape, and the fourth adhesive tape is 5μm≤δ≤16μm, the adhesion is 150~200g / 10mm, and the adhesive liquid is silicone; the adhesive liquid of the adhesive line is pure UV silicone, modified UV silicone, or acrylate UV adhesive, and the viscosity is 80000mPa·s≤P≤130000mPa·s.

[0018] Preferably, the single-sided overhang dimension of the positive electrode sheet and the composite electrode sheet is 1.5~3mm, and the width of the area where the edge of the positive electrode sheet presses against the surface of the insulating adhesive paper is 1.5~3mm.

[0019] The beneficial effects of this invention are as follows: This invention uses a composite protection scheme of "adhesive application + dispensing" to physically isolate the contact area between the positive electrode edge and the negative electrode by applying PI adhesive paper to the edge of the composite electrode. This avoids short circuits caused by shearing between the electrodes during isostatic pressing. At the same time, U-shaped adhesive is used to prevent the tabs from overlapping, and UV adhesive lines are applied in sections on the surface of the PI adhesive paper to provide uniform support for adjacent negative electrodes. This effectively compensates for the sagging and deformation of the negative electrode caused by the overhang design, thus completely avoiding the stress peak and electrolyte layer detachment risks caused by the arc-shaped cross-section of the adhesive lines in traditional adhesive coating processes. It also avoids the problems of mutual solubility between the insulating adhesive and the electrode material area, as well as material and powder shedding at the edge of the electrode. After adopting this method, the short circuit rate of large-capacity solid-state batteries (>60Ah) after isostatic pressing is reduced from 90% to 0.2%, achieving the same reliability level as liquid batteries, and significantly improving the manufacturing yield and engineering feasibility of solid-state batteries. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of the composite electrode adhesive application in an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the adhesive applied to the short side of the composite electrode sheet in an embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of the long side of the composite electrode being glued in an embodiment of the present invention; Figure 4This is a top view of the composite electrode sheet after dispensing in an embodiment of the present invention; Figure 5 This is a schematic diagram of the positive electrode sheet in an embodiment of the present invention; Figure 6 This is a schematic cross-sectional view of the positive electrode and composite electrode stacked in an embodiment of the present invention; Figure 7 The OCV distribution diagrams are shown for the voltage before and after voltage and after 12 hours of rest. In the diagram: 100, composite electrode; 210, first adhesive tape; 220, second adhesive tape; 230, third adhesive tape; 240, fourth adhesive tape; 300, first adhesive line; 310, second adhesive line; 400, positive electrode. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixed connection," and "fixed connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] This invention provides a short-circuit protection method for solid-state batteries, particularly suitable for the isostatic pressing process of high-capacity (e.g., >60Ah) sulfide-based solid-state batteries. This method employs a composite approach of "adhesive bonding + dispensing" to provide edge insulation and structural support for the composite electrode formed by the transfer of the negative electrode sheet and the electrolyte membrane, thereby reducing the risk of short circuits during the isostatic pressing process.

[0025] Example 1 1. Preparation of composite electrodes First, a negative electrode sheet (not shown) and a solid electrolyte membrane (not shown) are provided. The solid electrolyte membrane is transferred onto the surface of the negative electrode sheet using a transfer printing process to form a composite electrode sheet 100. In this embodiment, the solid electrolyte is a sulfide electrolyte, and the negative electrode sheet is a lithium metal or graphite negative electrode.

[0026] 2. Adhesive-coated edge protection for composite electrode sheets like Figures 1 to 3 As shown, the composite electrode 100 is positioned at the bonding station. Insulating adhesive paper with a PI (polyimide) substrate is used, the adhesive component is silicone, the adhesion strength is 150~200g / 10mm, and the adhesive paper thickness δ is 5μm≤δ≤16μm (preferably δ=10μm in this embodiment).

[0027] (1) Adhesive application on the short side of the non-tab side: The first adhesive tape 210 is applied to the short side of the composite electrode 100 on the non-tab side. When applying, the first adhesive tape 210 is U-shaped and covers both sides of the composite electrode 100, and is tightly attached to the short side end face of the composite electrode 100 with a gap of ≤0.5mm. The width W1 of the first adhesive tape 210 covering the composite electrode satisfies: W1>(L×λ1) / 2+△1, where L is the designed length of the electrode (L=200mm in this embodiment), λ1 is the shrinkage rate of the electrode in the length direction after isostatic pressing (measured λ1=0.5%), and △1 is the cumulative tolerance of the electrode's own tolerance and the alignment deviation of the stacked sheets (take △1=0.3mm). The calculated W1>(200×0.005) / 2+0.3=0.5+0.3=0.8mm, and the actual W1=1.2mm is taken.

[0028] (2) Long-side adhesive application: The second adhesive paper 220 and the third adhesive paper 230 are applied sequentially for insulation protection. One layer of PI adhesive paper is applied to both the front and back of the composite electrode 100 along each long side to form double-sided protection. The thickness δ of the adhesive paper is also 10μm, and the coverage width W2 satisfies: W2>(W×λ2) / 2+△1, where W is the designed width of the electrode (W=150mm in this embodiment), λ2 is the shrinkage rate in the width direction of the electrode after isostatic pressing (λ2=0.5%), △1=0.3mm, and W2>(150×0.005) / 2+0.3=0.375+0.3=0.675mm. In practice, W2=1.0mm is taken.

[0029] (3) Applying adhesive to the short side of the tab: Finally, protect the short side of the tab by applying the fourth adhesive tape 240. The calculation logic for the size of the edge of the electrode covered by the fourth adhesive tape 240 is the same as that for the first adhesive tape 210 on the short side of the non-tab side. A gap d is reserved at the junction of the second adhesive tape 220, the third adhesive tape 230 and the fourth adhesive tape 240, as well as the first adhesive tape 210 on the short side of the non-tab side, and 0≤d≤0.5mm (d=0.2mm in this embodiment) to ensure that the R-corner of the composite electrode is adequately protected.

[0030] 3. Apply adhesive to the surface of the adhesive line for support. like Figure 4 As shown, after the above adhesive application is completed, a ring of adhesive lines is formed on the upper surface of the PI adhesive paper protection area (i.e., the first adhesive paper 210, the second adhesive paper 220, the third adhesive paper 230, and the fourth adhesive paper 240) at the edge of the composite electrode 100 using a dispensing process. The adhesive lines include a first adhesive line 300 located in the non-thinned area and a second adhesive line 310 located in the thinned area on the tab side. The adhesive used is pure UV silicone with a viscosity range of 80,000~130,000 mPa·s (in this embodiment, P=100,000 mPa·s). During application, starting from a certain section on the upper surface of the second adhesive paper 220, adhesive is dispensed counterclockwise along the edge. The distance d3 between the adhesive line and the edge of the protective adhesive paper is ≤0.2 mm (in this embodiment, d3=0.1 mm) to avoid adhesive overflow that could cause adjacent electrodes to stick during stacking.

[0031] Because a thinning zone exists on the tab side during electrode coating, the thickness t2 of the composite electrode at the fourth adhesive paper 240 on the short side of the tab side is less than the thickness t1 in other areas. To achieve the best support effect, this embodiment sets the adhesive line thickness in different regions: Non-thinned region (corresponding to the first adhesive line 300 region): adhesive line thickness t1 = h - δ - λ3 - h×5%, where h is the thickness of the positive electrode sheet (h=120μm in this embodiment), δ is the thickness of the insulating adhesive paper (10μm), and λ3 is the isostatic compression ratio of the positive electrode sheet in the thickness direction (measured λ3=10μm). Then t1 = 120 - 10 - 10 - 120×5% = 120 - 20 - 6 = 94μm.

[0032] Thinning area on the tab side (corresponding to the second adhesive line 310 region): Adhesive line thickness t2 = h - δ - λ3 - h×5% + h×24.5% = 94 + 120×24.5% = 94 + 29.4 = 123.4μm.

[0033] After the adhesive is applied, the composite electrode is cured with a UV lamp for 5-10 seconds (8 seconds in this example) to ensure that the adhesive lines are completely cured.

[0034] 4. Positive electrode plate and stacking processing The positive electrode 400 does not require any insulation protection. An overhang is provided between the positive electrode 400 and the composite electrode 100, that is, the size of the negative electrode (composite electrode) is larger than that of the positive electrode, and the size of the overhang on one side is 1.5~3mm (2mm in this embodiment).

[0035] like Figure 5 and Figure 6 As shown, positive electrode 400 and composite electrode 100 treated as described above are alternately stacked to form a battery cell. The following two points need to be controlled during stacking: The edge of the positive electrode 400 must be pressed onto the upper surface of the insulating adhesive paper (i.e., the first adhesive paper 210, the second adhesive paper 220, the third adhesive paper 230, and the fourth adhesive paper 240) on the edge of the composite electrode 100, and the width of the pressing area is 1.5~3mm (2mm in this embodiment).

[0036] The edge of the positive electrode 400 must not extend beyond or be placed on the upper surface of the first adhesive line 300 or the second adhesive line 310.

[0037] After the wafers are stacked according to the set number of layers (e.g., 50 layers), the electrode assembly is ultrasonically welded and encapsulated, and then isostatically pressed with an isostatic pressure ≥ 500 MPa.

[0038] 5. Effect Verification Traditional screen printing or adhesive application can be used, as shown in Table 1.

[0039] High-capacity solid-state batteries with a capacity of 60Ah or more, prepared using the method of this embodiment, were tested. 118 batteries were verified, with 16 experiencing short circuits. After isostatic pressing, the short-circuit rate was 0.2%. The results show that compared to a comparative method using traditional screen printing or dispensing adhesive, this embodiment reduced the short-circuit rate from 90% to 0.2%, achieving a level comparable to liquid batteries. Furthermore, during assembly, no electrolyte layer shedding or powdering occurred at the edges of the composite electrode, and there was no miscibility between the insulating adhesive and the electrode material area, effectively protecting the edges of the negative electrode.

[0040] Example 2 This embodiment is basically the same as Embodiment 1, except that the adhesive tape thickness δ is 16μm, the adhesive strength is 200g / 10mm, the adhesive line viscosity is 130000mPa·s, the single-sided overhang dimension is 3mm, and the width of the positive electrode sheet 400 pressed onto the insulating adhesive tape is 3mm. Testing showed that the short-circuit rate was also below 0.5%, significantly better than existing technologies.

[0041] Example 3 This embodiment is basically the same as Embodiment 1, except that the adhesive used is an acrylic UV adhesive with a viscosity of 80,000 mPa·s, a curing time of 10 seconds, and the adhesive line thickness is adjusted accordingly based on the formula. Test results show that the short-circuit rate after isostatic pressing is 0.3%, demonstrating good protective performance.

[0042] For those skilled in the art, various improvements and modifications can be made without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A method for short-circuit protection of solid-state batteries, characterized in that, Includes the following steps: Step 1: Provide a composite electrode (100), which is formed by transferring a negative electrode sheet and a solid electrolyte membrane; Step 2: Adhere insulating tape to the edge of the composite electrode (100), including: A first adhesive tape (210) is pasted on the short side of the non-tab side of the composite electrode (100). The first adhesive tape (210) is U-shaped and covers both the front and back sides of the composite electrode (100) and is attached to the short side end face. A second adhesive tape (220) and a third adhesive tape (230) are respectively pasted on the first long side and the second long side of the composite electrode (100), and the second adhesive tape (220) and the third adhesive tape (230) are each pasted on both the front and back sides of the composite electrode (100); A fourth adhesive tape (240) is pasted on the short side of the tab side of the composite electrode (100). Step 3: Apply adhesive to the upper surfaces of the first adhesive tape (210), the second adhesive tape (220), the third adhesive tape (230) and the fourth adhesive tape (240), along the edge of the composite electrode (100) to form an adhesive line, and then UV cure the adhesive line; Step 4: Provide a positive electrode sheet (400), and alternately stack the positive electrode sheet (400) with the composite electrode sheet (100) processed in steps 1 to 3 to form a battery cell. When stacking, the edge of the positive electrode sheet (400) is pressed against the upper surface of the insulating adhesive paper, and the edge of the positive electrode sheet (400) does not extend beyond the upper surface of the adhesive line. Step 5: Package and isostatically pressurize the stacked cells.

2. The solid-state battery short-circuit protection method according to claim 1, characterized in that, The first adhesive tape (210), the second adhesive tape (220), the third adhesive tape (230) and the fourth adhesive tape (240) are all PI adhesive tapes, the adhesive liquid is silicone, the thickness δ is 5μm≤δ≤16μm, and the adhesion is 150~200g / 10mm.

3. The solid-state battery short-circuit protection method according to claim 1, characterized in that, The width W1 of the first adhesive tape (210) and the fourth adhesive tape (240) covering the composite electrode (100) satisfies: W1>(L×λ1) / 2+△1, where L is the design length of the composite electrode, λ1 is the shrinkage rate of the electrode in the length direction after isostatic pressing, and △1 is the cumulative tolerance of the electrode's own tolerance and the alignment deviation of the stacked sheets; the width W2 of the second adhesive tape (220) and the third adhesive tape (230) covering the composite electrode (100) satisfies: W2>(W×λ2) / 2+△1, where W is the design width of the composite electrode, and λ2 is the shrinkage rate of the electrode in the width direction after isostatic pressing.

4. The solid-state battery short-circuit protection method according to claim 1, characterized in that, A gap d is left at the junction of the second adhesive tape (220), the third adhesive tape (230), the fourth adhesive tape (240), and the first adhesive tape (210), and 0≤d≤0.5mm.

5. The solid-state battery short-circuit protection method according to claim 1, characterized in that, The adhesive line in step three includes a first adhesive line (300) located in the non-thinning area and a second adhesive line (310) located in the thinning area on the tab side; the adhesive used for the adhesive line is pure UV silicone, modified UV silicone or acrylate UV adhesive, with a viscosity range of 80000mPa·s≤P≤130000mPa·s, and the distance d3 between the adhesive line and the edge of the insulating adhesive paper is ≤0.2mm.

6. The solid-state battery short-circuit protection method according to claim 5, characterized in that, The thickness t1 of the first adhesive line (300) and the thickness t2 of the second adhesive line (310) are set according to the following formulas: t1 = h - δ - λ3 - h×5%; t2 = h - δ - λ3 - h×5% + h×24.5%; Where h is the thickness of the positive electrode sheet, δ is the thickness of the insulating paper, and λ3 is the compression ratio in the thickness direction of the positive electrode sheet under isostatic pressing.

7. The solid-state battery short-circuit protection method according to claim 1, characterized in that, In step four, the single-sided overhang dimension of the positive electrode (400) and the composite electrode (100) is 1.5~3mm, and the width of the area where the edge of the positive electrode (400) presses against the surface of the insulating adhesive paper during stacking is 1.5~3mm.

8. A solid-state battery prepared by the method according to any one of claims 1 to 7, characterized in that, The device includes an aluminum-plastic film housing and a stacked electrode assembly. The electrode assembly includes a positive electrode (400) and a composite electrode (100). The short side of the non-tab side of the composite electrode (100) is covered with a U-shaped first adhesive tape (210) covering both sides. The first and second long sides of the composite electrode (100) are covered with a second adhesive tape (220) and a third adhesive tape (230) on each side. The short side of the tab side of the composite electrode (100) is covered with a fourth adhesive tape (240). A UV-cured adhesive line is provided on the upper surface of the first adhesive tape (210), the second adhesive tape (220), the third adhesive tape (230), and the fourth adhesive tape (240). The edge of the positive electrode (400) is pressed against the upper surface of the insulating adhesive tape and does not extend beyond the upper surface of the adhesive line.

9. The solid-state battery according to claim 8, characterized in that, The thickness δ of the first adhesive tape (210), the second adhesive tape (220), the third adhesive tape (230), and the fourth adhesive tape (240) is 5μm≤δ≤16μm, the adhesion is 150~200g / 10mm, and the adhesive liquid is silicone; the adhesive liquid of the adhesive line is pure UV silicone, modified UV silicone, or acrylate UV adhesive, and the viscosity is 80000mPa·s≤P≤130000mPa·s.

10. The solid-state battery according to claim 8, characterized in that, The single-sided overhang dimension of the positive electrode (400) and the composite electrode (100) is 1.5~3mm, and the width of the area where the edge of the positive electrode (400) is pressed against the surface of the insulating adhesive paper is 1.5~3mm.

Images