Battery cell and method of processing thereof

Abstract

The application discloses an electric core and a processing method thereof, and comprises a core stack, a positive electrode tab, a negative electrode tab and a hot melt adhesive film unit piece for pre-packaging the core stack. The core stack is formed by alternately stacking a positive electrode sheet, a solid-state electrolyte layer and a negative electrode sheet, and the positive electrode tab and the negative electrode tab are respectively welded to the core stack. The hot melt adhesive film unit piece is formed by cutting a finished polyester composite hot melt adhesive film roll, and is wrapped on the outside of the core stack to form a pre-packaging structure; two pieces are respectively arranged on the front and back surfaces of the core stack and are aligned and packaged. After the electric core is subjected to vacuum sealing and isostatic pressing, part of the hot melt adhesive film unit piece is cut off at the sealing position on the non-tab side, so that the electric core is in a non-closed state, and subsequent aluminum-plastic film packaging is facilitated to form a solid-state soft package battery. The application can improve the adhesion between the core stack layers, the interface contact stability and the pre-packaging quality.

Description

Technical Field

[0001] This invention relates to the field of solid-state lithium-ion battery manufacturing, and more specifically to a battery cell and its processing method. Background Technology

[0002] Solid-state batteries use solid electrolytes instead of traditional liquid electrolytes, offering core advantages such as high energy density, long cycle life, and high safety. These advantages give solid-state batteries broad application prospects in electric vehicles, electronic products, and energy storage. Pouch cells, without the limitations of a rigid casing, offer higher volume utilization compared to prismatic aluminum-cased batteries. Furthermore, pouch cells allow for greater pressure during the packing stage, enhancing the solid-solid interface bonding. Therefore, pouch technology is highly suitable for manufacturing solid-state batteries. In solid-state battery manufacturing, isostatic pressing is a crucial step for cell densification. Without treatment during isostatic pressing, the aluminum-plastic film will shrink and wrinkle, severely affecting the cell's sealing performance. Summary of the Invention

[0003] Based on the above analysis, the present invention provides a battery cell, comprising: stacked cores, positive tabs, negative tabs, and hot melt adhesive film unit sheets for pre-packaging the stacked cores. The stacked core includes alternating layers of positive electrode sheets, solid electrolyte layer and negative electrode sheets, and the positive electrode tab and the negative electrode tab are respectively welded to the stacked core; The hot melt adhesive film unit sheet is formed by cutting finished polyester composite hot melt adhesive film rolls and wrapping it around the outside of the stacked core to form a pre-packaged structure; The battery cell undergoes vacuum sealing and isostatic pressing, and the hot melt adhesive film unit at the non-tab side of the battery cell is cut off for subsequent aluminum-plastic film encapsulation to form a solid-state soft-pack battery.

[0004] This invention links three processes together: cutting hot melt adhesive film rolls, vacuum sealing around the battery cell, and cutting and vacuum sealing after isostatic pressing. This allows the hot melt adhesive film rolls to achieve both the vacuum packaging required during isostatic pressing and the opening of the hot melt bag after isostatic pressing, thus realizing the feasibility of automated mass production.

[0005] Preferably, the positive and negative tabs are symmetrically arranged along the center line of the stacked core and welded to the stacked core.

[0006] The positive and negative tabs are symmetrically welded onto the stacked core, which can make the force and thickness distribution of the tabs more balanced, reduce indentations and stress concentration caused by local stacking in the sealing area; the deformation is smaller during isostatic pressing and subsequent aluminum-plastic film encapsulation, and the roots of the tabs are less prone to cracks or poor soldering.

[0007] Preferably, the hot melt adhesive film unit sheet covers the tab adhesive of the positive and negative tabs on both sides of the stacked core along the length direction. Based on the projection of the outermost edge of the tab adhesive to the edge of the stacked core, the coverage of the hot melt adhesive film unit sheet pressing the outer edge of the tab adhesive is 1.0-2.0 mm.

[0008] The hot melt adhesive film covers 1-2mm of tab adhesive on both sides along the length direction, which can form an insulating and buffered transition at the root of the tab, reducing the displacement of the tab adhesive caused by heat during sealing or friction.

[0009] Preferably, the sealing position of the tab side of the battery cell is based on the outermost boundary of the actual overlapping area of ​​the tab adhesive and the hot melt adhesive film unit sheet, the sealing line does not contact the tab adhesive body, and the overlap length is 1.0-2.0mm; the sealing position of the non-tab side is based on the outer edge of the stacked core, and the shortest distance from the sealing line to the edge of the stacked core is greater than or equal to 1.0mm.

[0010] The position of the tab-side seal is controlled at 1-2mm away from the overlap of the tab adhesive and the hot melt adhesive film. This ensures that the sealing line does not press on the tab adhesive and cause it to lift up, while also achieving the required sealing overlap length. The gap between the non-tab-side seal and the battery cell is greater than or equal to 1mm. This prevents the sealing line from directly pressing on the edge of the battery cell, thereby reducing edge damage and extrusion of inner layer materials, while also improving vacuum retention capacity and sealing reliability.

[0011] Preferably, the shortest straight-line distance between the edge of the hot melt adhesive film unit sheet and the outer edge of the stacked core is greater than or equal to 3.0 mm.

[0012] The shortest straight-line distance between the edge of the hot melt adhesive film unit and the outer edge of the stacked core is greater than or equal to 3.0 mm, which provides a safety boundary for vacuum sealing, avoids the heat sealing line being too close to affect the active area or press out creases, thereby improving the sealing strength and edge dimensional stability, and reducing the risk of short circuits and edge damage.

[0013] Preferably, the pre-packaging includes: placing two hot melt adhesive film unit sheets on the front and back sides of the stacked core respectively, and pre-packaging after the two hot melt adhesive film unit sheets are aligned with each other.

[0014] Pre-packaging involves covering and aligning different hot melt adhesive film units on the front and back of the core, which prevents relative slippage, edge misalignment, or wrinkles of the film material during sealing, thereby improving the consistency of the sealing appearance and size.

[0015] A method for processing the battery cell includes: S1. Use cutting equipment to cut the finished polyester composite hot melt adhesive film roll into hot melt adhesive film unit pieces, and weld the stacked core to the positive and negative electrode tabs; S2. Pre-package the stacked cores using the hot melt adhesive film unit sheet to form a battery cell; S3. Vacuum seal the battery cell using a vacuum sealing machine; S4. Perform isostatic pressing on the vacuum-sealed battery cell; S5. After the isostatic pressing process, the hot melt adhesive film unit sheet at the non-tab side sealing of the battery cell is removed using the cutting equipment. S6. The processed battery cell is encapsulated with an aluminum-plastic film to form a solid-state soft-pack battery.

[0016] This processing method uses polyester composite hot melt adhesive film to pre-package and vacuum seal the stacked cores, combined with isostatic pressing, which can improve the interfacial contact tightness between the solid electrolyte and the positive and negative electrode sheets, reduce interfacial impedance and enhance ion transport efficiency. At the same time, the hot melt adhesive film provides effective physical protection for the stacked cores under isostatic high pressure environment, preventing the stacked core structure from loosening or being damaged. The subsequent edge trimming and aluminum-plastic film secondary packaging process not only ensures the sealing reliability and long-term stability of the cell, but also maximizes the utilization of internal space, thereby improving the energy density, cycle life and safety performance of solid-state soft-pack batteries.

[0017] Preferably, when vacuum sealing the battery cell, the vacuum level is set to a negative pressure value that can expel the gas inside the pre-packaged structure and meet the sealing requirements.

[0018] The vacuum level of the vacuum pump is set to a negative pressure value that can expel the gas inside the pre-packaged structure and meet the sealing requirements. This can maximize the removal of air and volatiles from the temporary packaging, reduce bulging, internal delamination, or voids caused by gas compression during isostatic pressure, thereby improving the cell density and interface bonding quality, and reducing the probability of residual gas and appearance defects during the subsequent aluminum-plastic film final packaging.

[0019] Preferably, the pressure and processing time of the isostatic pressing process are set as parameters that can improve the interlayer bonding and interface contact stability within the stacked core.

[0020] By setting parameters for isostatic pressure and processing time, the solid system can be fully densified and its interface reconstructed under uniform pressure in all directions, resulting in tighter electrode contact, reduced porosity, and thus lower internal resistance. At the same time, the uniform pressure in all directions can reduce warping, uneven thickness, and edge damage caused by unidirectional pressing.

[0021] Preferably, the distance between the cut position of the battery cell at the non-tab side sealing point and the edge of the battery cell is 0.5mm-0.8mm, so that the hot melt adhesive film unit sheet is in an open state, thereby making the battery cell in a non-sealed state.

[0022] After isostatic pressing, the non-electrode side seal is cut off, and the cutting position is controlled at 0.5~0.8mm away from the cell, so that the package formed by the hot melt adhesive film is open and the cell is in a non-sealed state. Its function is to release the residual stress and trace gas that may exist after isostatic pressing, avoid wrinkles during subsequent aluminum-plastic film packaging, and provide a smooth assembly port for aluminum-plastic film bagging and final sealing, thereby reducing bulging and packaging wrinkles and improving the efficiency and stability of subsequent packaging.

[0023] Preferably, the hot melt adhesive film unit sheet that has not been cut off is retained on the surface of the battery cell.

[0024] The uncut side of the hot melt adhesive film unit remains on the surface of the cell, which can continuously provide surface protection and edge support during handling, transfer and aluminum-plastic film assembly, reducing dust contamination, scratches and corner cracks; thereby improving turnover reliability and cleanliness control level, and providing a more stable shape and positioning reference for subsequent aluminum-plastic film packaging.

[0025] The beneficial effects of this invention are as follows: By combining hot melt adhesive film unit cutting and tab welding, double hot melt adhesive film front and back alignment and pre-packaging, vacuum sealing according to the specified sealing boundary, isostatic pressing, non-tab side fixed-distance cutting, and aluminum-plastic film encapsulation, reliable positioning and vacuum environment establishment are achieved before isostatic pressing, uniform stress and controlled deformation are achieved during isostatic pressing, and it is easy to introduce into the conventional aluminum-plastic film encapsulation section after isostatic pressing, thus improving the overall process compatibility and mass production stability.

[0026] By constraining the dimensions of the hot melt adhesive film unit and the sealing position, continuous protection is formed at critical boundaries, reducing the risk of sealing damage, edge cracking, wrinkle misalignment and short circuit, and improving appearance and dimensional consistency and turnaround yield.

[0027] By combining vacuum and isostatic pressing, along with symmetrical tab welding, ultrasonic welding with low heat input, and pre-packaged alignment structure constraints, residual gas and internal voids are significantly reduced, and the bonding and densification uniformity of the solid interface are improved. At the same time, after isostatic pressing, the packaging bag is cut into an opening, so that the cell is not sealed and a film is retained on one side. This can release residual gas / stress and keep the surface clean and protected, thereby reducing the probability of subsequent aluminum-plastic film encapsulation bulging and gas trapping, and improving consistency and electrical performance stability. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1This is a flowchart of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, the following embodiments use a solid-state pouch cell as the object. In this embodiment, all dimensions are measured based on the outer contour of the stacked core (using a digital caliper with an accuracy of 0.01mm), and all vacuum and pressure parameters are based on the values ​​displayed by the device.

[0032] Materials and Equipment: Stacked core: A stacked core is formed by stacking solid positive electrode sheet, solid electrolyte layer and solid negative electrode sheet; the outer edges of the stacked core are flat and there are no obvious burrs or powder shedding.

[0033] Tab adhesive: Insulating adhesive (such as PI adhesive or equivalent insulating adhesive) applied to the transition area between the base of the tab and the edge of the stacked core. After application, it should be flat and without any curling edges.

[0034] Polyester composite hot melt adhesive film roll: The outer layer is a polyester substrate layer, and the inner layer is a hot melt adhesive layer; the hot melt adhesive layer is the bonding layer for subsequent heat sealing.

[0035] Main equipment: Servo-controlled fixed-length cutting machine (capable of cutting film materials and performing fixed-length edge cutting and sealing), ultrasonic welding machine (for electrode welding), pre-packaging positioning fixture (existing technology), vacuum sealing machine (with heat sealing head, adjustable vacuum level and heat sealing time / pressure), cold isostatic pressing equipment (CIP, pressure greater than or equal to 500MPa), aluminum-plastic film bagging and heat sealing equipment (flexible packaging machine, with vacuuming and heat sealing). Direction definition: Core length direction: The direction consistent with the direction of the long side of the core.

[0036] Core width direction: The direction perpendicular to the core length direction.

[0037] Electrode side: The two sides from which the electrode leads.

[0038] Non-polar ear side: The two sides extending from the non-polar ear.

[0039] S1: Cut the hot melt adhesive film unit sheet, and simultaneously stack the core and weld it to the positive and negative tabs.

[0040] S1-1: Hot melt adhesive film rolls are cut into hot melt adhesive film unit sheets: Install the polyester composite hot melt adhesive film roll onto the cutting equipment, set the tension to the minimum tension required for stable operation of the equipment (to ensure that the film surface is free of wrinkles and deviation), and turn on the correction function.

[0041] Set the cutting dimensions to obtain two hot melt adhesive film unit sheets of the same size, used for the front and back sides of the stacked core, respectively. The cutting dimensions are determined according to the following rules: On both sides of the stacked core length direction: the edge of the hot melt adhesive film unit sheet needs to cover the tab adhesive area by 1.0-2.0mm.

[0042] Measurement method: Based on the projection from the outermost edge of the tab adhesive to the edge of the stacked core, the coverage of the hot melt adhesive film unit edge pressing against the outer edge of the tab adhesive is 1.0-2.0mm.

[0043] On both sides of the core width direction: the distance between the edge of the hot melt adhesive film unit sheet and the outer edge of the core outline is greater than or equal to 3.0 mm.

[0044] Measurement method: The shortest straight-line distance from the edge of the diaphragm to the edge of the stacked core is greater than or equal to 3.0 mm.

[0045] Each membrane sheet should have neat edges without any gaps after cutting; if there are rough edges, tears or wrinkles, the membrane sheet will not proceed to the next process.

[0046] S1-2: The positive and negative electrodes are symmetrically welded onto the stacked core using ultrasonic welding. Place the stacked core in the center of the welding fixture, so that the center line of the stacked core coincides with the center line of the fixture.

[0047] Place the positive and negative tabs on opposite sides of the stack width direction, so that the lead-out positions of the two tabs are symmetrical about the stack center line; the symmetry error (the difference in distance from the root of the two tabs to the stack center line) is controlled within ≤0.5mm.

[0048] Ultrasonic welding was used to connect the electrode tab to the corresponding current collector. Post-weld inspection: Solder joint appearance: No obvious burning, burrs, or detached cold solder joints; Electrode position: After welding, the electrode must not cover the non-electrode side edge along the length of the stacked core (to avoid affecting subsequent edge sealing); S2: Pre-package stacked cores using hot melt adhesive film units to form battery cells. Take a hot melt adhesive film unit sheet and lay it flat on the lower pressure plate of the pre-packaging positioning fixture, with the hot melt adhesive layer facing upwards. Place the stacked core with the welded tabs in the center of the film sheet: The tabs on both sides of the stacked core are led out normally, without bending or being compressed; The distance between the edge of the membrane and the edge of the stacked core must be greater than or equal to 3.0 mm on both sides of the width direction of the stacked core.

[0049] Take another hot melt adhesive film unit and cover it on top of the stacked core, with the hot melt adhesive layer facing down, so that the outer edges of the two films are aligned; the alignment error is controlled within ≤0.5mm (the misalignment of the outer edge of any film is ≤0.5mm).

[0050] Pre-packaging and securing: Use the upper pressure plate of the pre-packaging positioning fixture to gently press and position the stacked core between the upper and lower films to prevent slippage; then perform a pre-seal at each of the four corners to ensure that the films do not shift relative to each other when transported to the vacuum sealing machine.

[0051] Pre-sealing position: approximately 5-10 mm from the inner side of the outer edge of the diaphragm; Pre-sealing requirements: It is only for positioning and fixing, and does not require the formation of a sealed vacuum.

[0052] After pre-packaging, the upper and lower films cover and stack the core to form a semi-finished battery cell, which is then stably put into the vacuum sealing process.

[0053] S3: Vacuum sealing machine performs vacuum sealing on the battery cells: The obtained semi-finished battery cell is placed into the sealing chamber of a vacuum sealing machine and adjusted to make the sealing area around it flat and wrinkle-free.

[0054] Set the vacuum conditions to -80kPa to -100kPa (relative to atmospheric pressure gauge readings are -80kPa to -100kPa). Immediately after vacuuming, perform heat sealing.

[0055] Set the heat-sealing position and distance (all four sides need to be sealed to form a vacuum-sealed bag required for isostatic pressure): Tab side sealing: The sealing line is set at the inner edge of the overlapping part of the tab adhesive and hot melt adhesive film unit, so that the sealing line is 1.0-2.0mm away from the boundary of the overlapping part.

[0056] Judgment method: Based on the outermost boundary of the actual overlap area between the tab adhesive and the diaphragm, the sealing line must not press against the tab adhesive body, and the overlap length must be within the range of 1.0-2.0mm.

[0057] Non-pole side sealing: Maintain a gap of greater than or equal to 1.0mm between the sealing line and the edge of the battery cell.

[0058] Judgment method: Based on the outer edge of the stacked core, the shortest distance from the sealing line to the edge of the stacked core is greater than or equal to 1.0 mm.

[0059] The heat sealing parameters are set according to the heat sealing window of the membrane material and solidified into a mass production formula (e.g., sealing temperature / pressure / time adopts the recommended values ​​of the membrane material supplier and is determined through sealing verification). After heat sealing, a continuous sealing line is formed, and the sealing line should be free of breaks and air bubble channels.

[0060] After vacuum sealing, the battery cell is completely sealed around the perimeter with a polyester composite hot melt adhesive film, creating a high vacuum environment inside, which is then used for the isostatic pressing process.

[0061] S4: Perform isostatic pressing on the vacuum-sealed battery cells: Inspect the appearance of the battery cell vacuum bag: the sealing line is intact and there are no tears; the inside of the bag is well-fitted and there are no obvious areas of residual air bubbles.

[0062] After vacuum sealing, place the battery cell into the pressure chamber of the cold isostatic pressing equipment (the pressure medium is determined according to the equipment requirements, such as water-based or oil-based medium). The battery cell should be laid flat in the pressure chamber to avoid folding or squeezing the tabs.

[0063] Set and execute isostatic parameters: Pressure: 100MPa~600MPa; Pressure holding time: 60 seconds to 600 seconds (timing starts after reaching 500MPa); The pressurization and depressurization processes are executed according to the equipment's default safety procedures to ensure that the cells do not rupture due to instantaneous impact.

[0064] After the process is completed, the battery cell is removed, the surface dielectric is wiped dry, and the appearance is checked to ensure that the vacuum bag is not broken or has obvious delamination.

[0065] S5: After isostatic pressing, cut off the non-polar tab side seal to create an open state: The battery cell is placed in the positioning fixture of the cutting equipment, and the positioning reference is selected as the non-electrode edge of the stacked core outline.

[0066] Choose one of the non-polar ear sides as the excision edge.

[0067] Set the cutting line: The cutting line is parallel to the edge of the stacked core, and the distance from the cutting line to the edge of the cell is 0.5-0.8mm.

[0068] Measurement method: After cutting, use calipers to measure the shortest distance from the edge of the cell to the edge of the cut, which should fall within the range of 0.5-0.8mm.

[0069] Perform the cutting: Cut through the sealing edge on this side in one go and remove the cut sealing strip.

[0070] Cutting completion status determination: A continuous opening is formed on the non-polar ear side that was removed; The battery cell is in a non-sealed state; The rest of the seals remained intact; Uncut hot melt adhesive film unit sheets are left on the surface of the battery cell for transport protection and subsequent bagging positioning.

[0071] S6: The processed battery cells undergo solid-state soft-pack battery aluminum-plastic film encapsulation process. Prepare an aluminum-plastic film soft-pack shell (either a pre-formed aluminum-plastic film bag or a two-piece encapsulation structure is acceptable), and set an outlet at the electrode lead-out position that matches the width of the electrode (to avoid squeezing the electrode).

[0072] Insert the battery cell through the opening of the aluminum-plastic film bag: The tabs emerge naturally from the aluminum-plastic film outlet, without twisting or overlapping; The edges of the battery cells fit flush against the inner wall of the bag to prevent wrinkles from getting caught in the sealing area.

[0073] Perform heat sealing of aluminum-plastic film (vacuum heat sealing is preferred when the sealing machine has a vacuum function): Vacuuming: Set the equipment to near full evacuation (e.g., a stable value in the range of -95kPa to -99kPa) to reduce residual gas in the packaging; Heat sealing: Set and solidify the mass production formula according to the heat sealing process window of the inner layer of aluminum-plastic film to form a continuous sealing line.

[0074] After packaging, check the following: There was no material trapped or membrane broken in the tab lead-out area; The sealing line is continuous and without any gaps; The battery cell has no obvious top seal, wrinkles, or indentations within the aluminum-plastic film.

[0075] The prior description of the invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the invention will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the invention. Thus, the invention is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0076] The embodiments of the present invention have been described in detail above. The description of the embodiments above is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0077] The embodiments of the present invention have been described in detail above. The description of the embodiments above is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A battery cell, characterized in that, include: Stacked core, positive electrode tab, negative electrode tab, and hot melt adhesive film unit sheet for pre-packaging the stacked core; The stacked core includes alternating layers of positive electrode sheets, solid electrolyte layer and negative electrode sheets, and the positive electrode tab and the negative electrode tab are respectively welded to the stacked core; The hot melt adhesive film unit sheet is formed by cutting finished polyester composite hot melt adhesive film rolls and wrapping it around the outside of the stacked core to form a pre-packaged structure; The battery cell undergoes vacuum sealing and isostatic pressing, and the hot melt adhesive film unit at the non-tab side of the battery cell is cut off for subsequent aluminum-plastic film encapsulation to form a solid-state soft-pack battery.

2. The battery cell according to claim 1, characterized in that, The positive and negative tabs are symmetrically arranged along the center line of the stack and welded to the stack.

3. The battery cell according to claim 1, characterized in that, The hot melt adhesive film unit sheet covers the tab adhesive of the positive and negative tabs on both sides of the stacked core along the length direction. Based on the projection of the outermost edge of the tab adhesive to the edge of the stacked core, the coverage of the outer edge of the hot melt adhesive film unit sheet pressing against the outer edge of the tab adhesive is 1.0-2.0mm.

4. The battery cell according to claim 3, characterized in that, The sealing position of the battery cell tab side is based on the outermost boundary of the actual overlapping area of ​​the tab adhesive and the hot melt adhesive film unit sheet. The sealing line does not contact the tab adhesive body, and the overlap length is 1.0-2.0mm. The sealing position of the non-tab side is based on the outer edge of the stacked core. The shortest distance from the sealing line to the edge of the stacked core is greater than or equal to 1.0mm.

5. The battery cell according to claim 1, characterized in that, The shortest straight-line distance between the edge of the hot melt adhesive film unit and the outer edge of the stacked core is greater than or equal to 3.0 mm.

6. The battery cell according to claim 1, characterized in that, The pre-packaging includes: placing two hot melt adhesive film unit sheets on the front and back sides of the stacked core respectively, and pre-packaging after the two hot melt adhesive film unit sheets are aligned with each other.

7. A method for processing the battery cell according to claim 1, characterized in that, include: S1. Use cutting equipment to cut the finished polyester composite hot melt adhesive film roll into hot melt adhesive film unit pieces, and weld the stacked core to the positive and negative electrode tabs; S2. Pre-package the stacked cores using the hot melt adhesive film unit sheet to form a battery cell; S3. Vacuum seal the battery cell using a vacuum sealing machine; S4. Perform isostatic pressing on the vacuum-sealed battery cell; S5. After the isostatic pressing process, the hot melt adhesive film unit sheet at the non-tab side sealing of the battery cell is removed using the cutting equipment. S6. The processed battery cell is encapsulated with an aluminum-plastic film to form a solid-state soft-pack battery.

8. The method according to claim 7, characterized in that, When vacuum sealing the battery cell, the vacuum level is set to a negative pressure value that can expel the gas inside the pre-packaged structure and meet the sealing requirements.

9. The method according to claim 7, characterized in that, The pressure and processing time of the isostatic pressing process are set as parameters that can improve the interlayer bonding and interface contact stability within the stacked core.

10. The method according to claim 7, characterized in that, The distance between the cut position of the battery cell at the non-tab side sealing point and the edge of the battery cell is 0.5mm-0.8mm, so that the hot melt adhesive film unit sheet is in an open state, thereby making the battery cell in a non-sealed state.

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