Method, device and equipment for eliminating winding cell wrinkles and storage medium

Abstract

The present application relates to the technical field of winding hot-pressing process, and discloses a method, device, equipment and storage medium for eliminating the creases of a wound battery cell, the method comprising: slitting and roll-folding a positive plate, a separator and a negative plate to form a composite core; adjusting the winding parameters of a winding machine, and winding the composite core on the machine based on the adjusted winding parameters to obtain a wound battery cell; performing glue sticking on both sides of the wound battery cell, hot-pressing the wound battery cell after the glue sticking, and packaging the wound battery cell after the hot-pressing, the present application precisely controls the tension and alignment of the plate and the separator through slitting, roll-folding, parameterized winding and hot-pressing shaping process, effectively reduces the misalignment and stress concentration generated in the winding process, and thus significantly reduces the internal crease rate of the battery cell.

Description

Technical Field

[0001] This invention relates to the field of winding hot pressing technology, and specifically to a method, apparatus, equipment, and storage medium for eliminating wrinkles in wound battery cells. Background Technology

[0002] The booming development of the new energy vehicle industry has made it an important player in the global automotive industry transformation, and the market demand for its core power batteries is becoming increasingly urgent. Currently, power battery manufacturing mainly adopts two processes: lamination and winding. Among them, the winding process is widely used by the vast majority of cell manufacturers due to its comprehensive advantages such as high degree of automation, mature supporting industrial chain, low production cost and high yield.

[0003] However, existing winding processes have significant problems in production practice. The inherent limitations of the winding process itself can lead to defects in the quality of the battery cell itself. Specifically, uneven stress on the outer ring of the cell after winding can cause wavy edges on the negative electrode, and the separator can be excessively stretched. These internal stresses are released in a concentrated manner during the subsequent hot pressing process, ultimately resulting in persistent through-wrinkles on the surface of the negative electrode sheet, especially in the central area of ​​the large surface and on the non-tab side, which seriously affects the performance and safety of the battery. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method, apparatus, device and storage medium for eliminating wrinkles in wound battery cells, in order to solve the problems of uneven stress on the outer ring of the battery cell causing negative electrode wavy edges, and excessive tension of the separator causing difficult-to-eliminate through-type wrinkles on the surface of the negative electrode sheet.

[0005] In a first aspect, embodiments of the present invention provide a method for eliminating wrinkles in wound battery cells, the method comprising: The positive electrode, separator, and negative electrode are slited and rolled to form a composite core; Adjust the winding parameters of the winding machine, and wind the composite core on the machine based on the adjusted winding parameters to obtain a wound battery cell; Adhesive is applied to both sides of the wound cell, the glued wound cell is hot-pressed, and the hot-pressed wound cell is then encapsulated.

[0006] This invention relates to the field of winding and hot pressing technology, and discloses a method, apparatus, equipment, and storage medium for eliminating wrinkles in wound battery cells. The method includes: slitting and stacking a positive electrode sheet, a separator, and a negative electrode sheet to form a composite core; adjusting the winding parameters of a winding machine, and winding the composite core on the machine based on the adjusted winding parameters to obtain a wound battery cell; applying adhesive to both sides of the wound battery cell; hot pressing the glued wound battery cell; and encapsulating the hot-pressed wound battery cell. This invention, through slitting and stacking, parameterized winding, and hot pressing shaping processes, precisely controls the tension and alignment of the electrode sheet and the separator, effectively reducing misalignment and stress concentration generated during the winding process, thereby significantly reducing the internal wrinkle rate of the battery cell.

[0007] In conjunction with the first aspect, in one embodiment, adjusting the winding parameters of the winding machine includes: The first initial tension applied to the positive electrode sheet by the winding machine during the first turn of the composite core is obtained; The first initial tension applied to the positive electrode is controlled to decrease linearly, wherein the first initial tension decreases by 2 grams per revolution until a preset first tail-turn tension is reached.

[0008] This embodiment obtains and controls the initial tension of the positive electrode sheet to perform a linear decrease, ensuring a tight fit between the inner electrode sheet and the separator and preventing the formation of an initial gap. At the same time, the linearly decreasing tension control method can uniformly reduce the radial binding force on the positive electrode sheet as the winding diameter increases, effectively avoiding the problem of excessive compression of the inner ring by the outer ring due to constant tension or the problem of interlayer loosening caused by a sudden drop in tension.

[0009] In conjunction with the first aspect, in one embodiment, adjusting the winding parameters of the winding machine further includes: The second initial tension applied to the negative electrode sheet by the winding machine during the first turn of the composite core is obtained; The second initial tension applied to the negative electrode is controlled to decrease linearly, wherein the second initial tension decreases by 2 grams per revolution until a preset second tail-turn tension is reached.

[0010] This embodiment obtains and controls the second initial tension of the negative electrode sheet to perform a linear decrease, ensuring a tight fit between the outer electrode sheet and the separator and preventing the formation of initial gaps. At the same time, the linearly decreasing tension control method can uniformly reduce the radial binding force on the negative electrode sheet as the winding diameter increases, effectively avoiding the problem of excessive compression of the inner ring by the outer ring due to constant tension or the problem of interlayer loosening caused by a sudden drop in tension.

[0011] In conjunction with the first aspect, in one embodiment, adjusting the winding parameters of the winding machine further includes: The third initial tension applied to the diaphragm by the winding machine during the first turn of the composite core is obtained; The third initial tension applied to the diaphragm is controlled to decrease linearly, wherein the third initial tension decreases by 2 grams per revolution until a preset third tail-turn tension is reached.

[0012] This embodiment optimizes the stress state of the diaphragm during winding by acquiring and controlling the third initial tension of the diaphragm and decreasing it linearly. At the same time, the linear tension control method keeps the diaphragm moderately taut in the early stage of winding, ensuring that it flatly wraps the electrode sheet. As the winding diameter increases, the tension is gradually reduced, which effectively avoids excessive stretching, thinning or micropore deformation of the diaphragm caused by continuous high tension, and also prevents wave wrinkles caused by tension relaxation in the later stage.

[0013] In conjunction with the first aspect, in one embodiment, applying adhesive to both sides of the wound battery cell includes: An adhesive applicator is installed after the winding machine to apply adhesive to both sides of the wound battery cell in order to fix the wound battery cell.

[0014] In this embodiment, an adhesive applicator is configured after the winding machine to bind the end face of the wound battery cell, which effectively prevents the interlayer material from loosening and misaligning during the transfer process, providing a stable foundation for subsequent processing.

[0015] In conjunction with the first aspect, in one embodiment, the hot-pressing of the glued wound battery cell and the encapsulation of the hot-pressed wound battery cell includes: The wound battery cell after adhesive application is hot-pressed to obtain the first intermediate wound battery cell; The first intermediate wound cell is cold-pressed and then packaged to obtain the target wound cell.

[0016] In this embodiment, the hot pressing process uses temperature and pressure to soften the bonding material and eliminate interlayer gaps, thereby improving the density, roundness consistency and interface bonding strength of the battery cell.

[0017] In conjunction with the first aspect or its corresponding implementation, in one embodiment, the step of cold-pressing the first intermediate wound cell and encapsulating the cold-pressed first intermediate wound cell to obtain the target wound cell includes: The cold pressing pressure and cold pressing time are adjusted, and the first intermediate wound cell is cold-pressed based on the adjusted cold pressing pressure and cold pressing time. The cold-pressed first intermediate wound cell is then packaged to obtain the target wound cell. The cold pressing pressure is adjusted to a range of 4 to 5 tons, and the cold pressing time is adjusted to a range of 4 to 5 seconds.

[0018] The cold pressing process in this embodiment can release the internal stress generated by hot pressing, suppress dimensional springback, and ensure high stability of cell size and shape lock.

[0019] Secondly, embodiments of the present invention provide a device for eliminating wrinkles in wound battery cells, the device comprising: The pre-processing module is used to slit and roll the positive electrode sheet, separator and negative electrode sheet to form a composite core; The winding module is used to adjust the winding parameters of the winding machine and to wind the composite core on the machine based on the adjusted winding parameters to obtain a wound battery cell. The encapsulation module is used to apply adhesive to both sides of the wound cell, heat-press the glued wound cell, and encapsulate the heat-pressed wound cell.

[0020] Thirdly, embodiments of the present invention provide a computer device, including: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the winding cell wrinkle elimination method of the first aspect or any corresponding embodiment described above.

[0021] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer instructions for causing a computer to perform the method for eliminating wrinkles in a wound battery cell as described in the first aspect or any corresponding embodiment. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 It is based on a schematic diagram of the outer ring folds of a wound battery cell in related technologies; Figure 2 This is a schematic flowchart of a method for eliminating wrinkles in wound battery cells according to some embodiments of the present invention; Figure 3(a) is a schematic diagram of the state of the wound cell after improvement according to some embodiments of the present invention; Figure 3(b) is a schematic diagram of the improved state of the outer ring of the negative electrode according to some embodiments of the present invention; Figure 3(c) is a schematic diagram of the improved hot-pressed state according to some embodiments of the present invention; Figure 4 This is a structural block diagram of a device for eliminating wrinkles in a wound battery cell according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed Implementation

[0024] 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.

[0025] According to an embodiment of the present invention, a method for eliminating wrinkles in wound battery cells is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0026] The booming development of the new energy vehicle industry has made it an important player in the global automotive industry transformation, and the market demand for its core power batteries is becoming increasingly urgent. Currently, power battery manufacturing mainly adopts two processes: lamination and winding. Among them, the winding process is widely used by the vast majority of cell manufacturers due to its comprehensive advantages such as high degree of automation, mature supporting industrial chain, low production cost and high yield.

[0027] However, existing winding processes have significant problems in production practice. The inherent limitations of the winding process itself can lead to quality defects in the battery cell itself. Specifically, uneven stress on the outer ring of the cell after winding can cause wavy edges on the negative electrode, and the separator can become excessively tight. These internal stresses are released in a concentrated manner during the subsequent hot-pressing process, ultimately resulting in persistent, through-type wrinkles on the surface of the negative electrode sheet, especially in the central area and on the non-tab side, which severely affect battery performance and safety. (Refer to...) Figure 1 The diagram shows a schematic of the outer ring wrinkles of a wound battery cell in the relevant technology. It shows the state of the wound battery cell and the state of the outer ring of the negative electrode before the improvement. Due to the mismatch between the tension of the separator and the negative electrode, the tension of the separator is in a tight state, while the tension of the outermost negative electrode is relatively loose. Therefore, under the constraint of the separator tension, the outermost negative electrode presents a wavy shape, so wrinkles will appear in the wound battery cell after the hot pressing process.

[0028] Based on this, this embodiment provides a method for eliminating wrinkles in wound battery cells. Figure 2 This is a flowchart of a method for eliminating wrinkles in a wound battery cell according to an embodiment of the present invention, as shown below. Figure 2 As shown, the process includes the following steps: Step S201: The positive electrode sheet, separator and negative electrode sheet are slited and rolled to form a composite core.

[0029] Step S202: Adjust the winding parameters of the winding machine, and wind the composite core on the machine based on the adjusted winding parameters to obtain the wound cell.

[0030] Step S203: Apply adhesive to both sides of the wound cell, heat-press the glued wound cell, and encapsulate the heat-pressed wound cell.

[0031] The method for eliminating wrinkles in wound cells provided in this embodiment involves slitting and stacking the positive electrode sheet, separator, and negative electrode sheet to form a composite core; adjusting the winding parameters of the winding machine and winding the composite core based on the adjusted winding parameters to obtain a wound cell; applying adhesive to both sides of the wound cell; hot-pressing the glued wound cell; and encapsulating the hot-pressed wound cell. This invention, through slitting and stacking, parameterized winding, and hot-pressing shaping processes, precisely controls the tension and alignment of the electrode sheet and separator, effectively reducing misalignment and stress concentration during the winding process, thereby significantly reducing the wrinkle rate inside the cell.

[0032] In step S201, the positive electrode sheet, separator and negative electrode sheet are slited and rolled to form a composite core.

[0033] In one embodiment, the positive electrode sheet, separator, and negative electrode sheet coated with active material are first cut along their length into strips of designed width. During slitting, the edge quality and width tolerance must be strictly controlled to ensure that the widths of each layer of material match during subsequent stacking.

[0034] Next, the slit positive electrode sheet, separator, and negative electrode sheet are pre-stacked according to the cell winding structure design requirements. The typical stacking sequence is: first separator layer, positive electrode sheet layer, second separator layer, and negative electrode sheet layer, forming a four-layer or multi-layer composite strip structure, so that the materials of each layer have established a stable relative positional relationship before entering the winding process.

[0035] This embodiment eliminates the problem of inconsistent width caused by cutting errors in wide materials by standardizing the dimensions of the slitting process. At the same time, the pre-rolled composite core structure provides a stable structural reference for the entire winding process, which can significantly reduce the occurrence rate of defects such as electrode wrinkles and diaphragm stretching deformation caused by interlayer relative sliding or uneven tension.

[0036] In step S202, the winding parameters of the winding machine are adjusted, and the composite core is wound on the machine based on the adjusted winding parameters to obtain a wound battery cell.

[0037] Figure 3(a) shows a schematic diagram of the state of the wound cell after improvements according to some embodiments of the present invention. In one embodiment, the present invention adjusts the winding parameters of the winding machine. The winding parameters refer to various process variables controlled by the winding machine during the winding process, including but not limited to the tension applied to each layer of material, the winding speed, and the correction parameters. In this embodiment, the winding parameters are used to represent the tension parameters applied to the positive electrode, the negative electrode, and the separator.

[0038] The initial tension reference values ​​preset for each layer of material in the winding machine are obtained separately. The initial tension reference values ​​include the first initial tension applied to the positive electrode sheet, the second initial tension applied to the negative electrode sheet, and the third initial tension applied to the separator. The initial tension reference value refers to the specific tension force actively applied to each layer of strip material (such as positive electrode sheet, negative electrode sheet, and separator) by the winding machine through its unwinding mechanism and tension control system at the beginning of the winding stage (i.e., the first turn of winding).

[0039] The specific embodiments of this invention adjust the manufacturing process parameters of wound batteries through a series of comparative experiments, aiming to significantly reduce the outer ring wrinkle rate of the battery cell after cold pressing and hot pressing. First, the initial scheme sets the tension of the positive and negative electrode sheets to a constant tension of 450 g / L, the tension of the main body section of the separator to a constant tension of 280 g / L, and the tension of the flip section of the separator to a constant tension of 320 g / L. The cold pressing pressure is 2 tons, and the cold pressing time is 4 seconds. Under this scheme, the outer ring wrinkle rate is as high as approximately 90%, which cannot meet the quality requirements.

[0040] To address this deficiency, this embodiment validated a gradient reduction strategy for the diaphragm body tension. While keeping other initial parameters constant, two reduction modes were tested: one was a reduction of 2 g / L in the diaphragm body tension every 5 turns, which resulted in a wrinkle rate of 77.78% after sample verification; however, this mode caused tab misalignment. The second mode was a reduction of 5 g / L in the diaphragm body tension every 5 turns, but this mode was not feasible due to an excessively large reduction coefficient causing equipment alarms. Subsequently, different constant tension values ​​for the diaphragm body were verified. The results showed that the wrinkle rate was 73% at a constant tension of 350 g / L, 61% at 320 g / L, and while it decreased to 51% at 260 g / L, it was accompanied by slight diaphragm delamination. Delamination intensified at a constant tension of 240 g / L, indicating that simply reducing the constant tension value can reduce wrinkles but may introduce delamination risks.

[0041] Further verification of the linearly decreasing diaphragm tension pattern was conducted by setting the initial tension of the diaphragm to 320 gf and the target tension of the final loop to 200 gf. When the tension was decreased by 2 gf per loop, the wrinkle rate dropped significantly to 35%; when decreased by 3 gf per loop, the wrinkle rate was 42.5%; however, a decrease of 5 gf per loop triggered an alarm again due to excessively rapid reduction. This stage of the experiment demonstrates that the gradually decreasing tension strategy is effective. Furthermore, when the tension of the diaphragm rotation section was gradually reduced from the initial 320 gf to 300 gf, 280 gf, 250 gf, 220 gf, and 180 gf, the corresponding wrinkle rates were 64%, 51.56%, 31.25%, 32.8%, and 25%, respectively, proving that reducing the rotation tension has a significant and positive effect on improving wrinkle reduction.

[0042] Finally, the effect of cold pressing pressure on the wrinkle rate was verified. Based on the initial scheme, the cold pressing pressure was increased to 4 tons, 5 tons, 6 tons, and 7 tons for verification. Table 1 shows the wrinkle rate verification table for different cold pressing pressures. The data shows that appropriately increasing the cold pressing pressure helps improve the outer ring wrinkles, with the effect being most ideal at 5 tons of pressure. Based on the above multi-dimensional experimental results, this invention ultimately optimizes a combination of synergistic process parameters, such as controlling the diaphragm tension to decrease by 2 grams per turn, setting the diaphragm flipping tension in the range of 180 to 250 grams, and adjusting the cold pressing pressure to 5 tons. This combination can reduce the outer ring wrinkle rate from nearly 90% to below 50%, while effectively avoiding secondary problems such as diaphragm delamination and tab misalignment.

[0043] Table 1. Verification of Wrinkle Rate under Cold Pressing Pressure

[0044] As can be seen from Table 1, when the cold pressing pressure is adjusted from 2T to 5T, the outer ring wrinkle rate decreases, while when the cold pressing pressure is adjusted from 5T to 6T, the outer ring wrinkle rate gradually increases. This indicates that the optimal wrinkle rate corresponds to a cold pressing pressure of around 5T.

[0045] Based on the aforementioned multiple rounds of parameter verification, this invention conducted a deeper comprehensive verification to further optimize and determine the final process scheme. Specifically, it attempted to set the tension of the positive and negative electrode sheets to a decreasing mode synchronized with the separator. Referring to Table 2, the tension adjustment strategy in the first improved scheme is shown. Specifically, based on the separator flipping tension of 180 g / L, the cold pressing pressure of 5 tons, and the cold pressing time of 4 seconds, the first improved scheme sets the initial tensions of the separator and the positive and negative electrode sheets to 320 g / L and 500 g / L, respectively, and decreases them by 2 g / L per turn, respectively, to 200 g / L and 380 g / L at the end of the turn.

[0046] Table 2 Tension Adjustment Table for the First Improved Scheme

[0047] Table 3 shows the wrinkle rate of the first improved scheme. When the sample was tested using the first improved scheme, the wrinkle rate decreased to 22.4%, demonstrating the effectiveness of the multi-component tension reduction strategy. In contrast, in the second improved scheme, the initial tension of the positive and negative electrodes was increased to 600 gF, while other parameters remained unchanged. When the sample was tested using the second improved scheme, the wrinkle rate increased to 44.79%, indicating that excessively high electrode initial tension is actually detrimental to wrinkle control.

[0048] Table 3. Wrinkle Rate Verification Table for the First Improved Scheme

[0049] Subsequently, based on the first improvement scheme, the third improvement scheme adjusted the initial tension of the positive and negative electrodes to 450 g / L and extended the cold pressing time from 4 seconds to 5 seconds.

[0050] Table 4 Tension Adjustment Table for the Third Improvement Scheme

[0051] Table 5 shows the wrinkle rate of the third improved scheme. The sample was verified using the third improved scheme, and the wrinkle rate was significantly reduced to 22.4%, which proves that by appropriately extending the cold pressing time based on the optimized tension reduction strategy, the wrinkle rate can be further improved.

[0052] Table 5. Wrinkle Rate Verification Table for the Third Improved Scheme

[0053] Based on this, the effects of adjusting the cold pressing time from 5 seconds to 10 seconds and 15 seconds were verified in the fourth improved scheme. The fourth improved scheme was used to verify the samples, as shown in Table 6, which shows the wrinkle rate of the fourth improved scheme.

[0054] Table 6. Wrinkle Rate Verification Table for the Fourth Improved Scheme

[0055] It is evident that adjusting the cold pressing time to 10 seconds and 15 seconds increased the wrinkle rate, therefore the cold pressing time should still be kept at 5 seconds.

[0056] Based on the fourth improved scheme, the electrode tension parameters were further refined and verified. Experiments showed that, with the initial tension of the separator at 320 gf and decreasing by 2 gf to 200 gf with each subsequent turn, the separator flipping tension at 180 gf, the cold pressing pressure at 5 tons, and the time at 5 seconds, supplemented by a strategy of applying U-shaped high-temperature adhesive to both sides of the core, the initial tension of the positive and negative electrodes could be adjusted within a relatively wide range of 450 gf ± 50 gf, decreasing by 2 gf with each subsequent turn until the final tension reached 380 gf. This maintained a wrinkle rate of less than 3%, demonstrating the robustness of the process window.

[0057] Ultimately, based on all verification results, this embodiment determined the optimal winding battery production process. Key parameters of this process include: optimizing the cold pressing pressure from the initial 2 tons to 5 tons, and the cold pressing time from 4 seconds to 5 seconds; setting the separator tension to decrease by 2 grams per turn from the first turn (320 g / L) to the last turn (200 g / L); setting the positive and negative electrode tension to decrease by 2 grams per turn from the first turn (450 g / L) to the last turn (380 g / L); and attaching U-shaped high-temperature adhesive to both sides of the core after the winding process. Large-scale verification using this final optimized solution significantly reduced the wrinkle rate, thus solving the problem of wrinkles on the outer ring of the cell and achieving extremely high product consistency and quality reliability.

[0058] In a preferred embodiment of the present invention, after the composite core is mounted on the machine, the winding machine can set the first initial tension of the positive electrode sheet to 450 g / L, the first tail tension to 380 g / L, the second initial tension of the negative electrode sheet to 450 g / L, the second tail tension to 380 g / L, the third initial tension of the separator to 320 g / L, and the third tail tension to 200 g / L.

[0059] For example, for both the positive and negative electrode plates, if the first and second initial tensions are both 450 g / L, the first turn of winding is still 450 g / L. Subsequently, both tensions decrease at the same rate of 2 g / L per turn until they decrease to 380 g / L. At this point, at least 35 turns have been decelerated. After that, the winding is maintained at 380 g / L until the winding is finished.

[0060] A "turn" refers to the basic counting unit in the winding of a battery cell, specifically, one complete rotation of the composite core around the central winding needle. The number of turns directly affects the cell's diameter, number of layers, and final capacity. Grams (grams) is a unit of force; 1 gram of force represents the force required to produce gravitational acceleration (approximately 9.8 m / s²) for 1 gram of mass. In this embodiment, it is used as a unit of tension measurement. For the separator, for example, the third initial tension is 320 grams of force. The first turn is also 320 grams of force, and then the third initial tension decreases at a rate of 2 grams of force per turn until it decays to 200 grams of force, at which point at least 60 turns have been decayed. Afterward, the tension is maintained at 200 grams of force until winding is complete. Alternatively, the separator's flip tension can be set to 180 grams of force. Figure 3(b) shows a schematic diagram of the improved state of the outer ring of the negative electrode according to some embodiments of the present invention.

[0061] Specifically, the first initial tension of the positive electrode winding is The tension of the first winding is still Then its first The tension of the coil winding is:

[0062] in, Indicates the positive electrode. The tension of the coil winding; This indicates the tension of the first winding of the positive electrode. Kelp; This indicates that the current winding is the first one. lock up.

[0063] Specifically, the second initial tension of the negative electrode winding is The tension of the first winding is still Then its first The tension of the coil winding is:

[0064] in, Indicates the negative electrode The tension of the coil winding; This indicates the tension of the first winding of the negative electrode. Kelp; This indicates that the current winding is the first one. lock up.

[0065] Specifically, the third initial tension of the diaphragm winding is The tension of the first winding is still Then its first The tension of the coil winding is:

[0066] in, Indicates the diaphragm The tension of the coil winding; This indicates the tension of the first turn of the diaphragm winding. Kelp; This indicates that the current winding is the first one. lock up.

[0067] Specifically, the steps include the following: The first initial tension applied to the positive electrode sheet by the winding machine during the first turn of the composite core is obtained; the first initial tension applied to the positive electrode sheet is controlled to decrease linearly, wherein the first initial tension decreases by 2 grams per turn until the preset first tail turn tension is reached.

[0068] The second initial tension applied to the negative electrode sheet during the first winding of the composite core by the winding machine is obtained; the second initial tension applied to the negative electrode sheet is controlled to decrease linearly, wherein the second initial tension decreases by 2 grams per turn until the preset second tail turn tension is reached.

[0069] The third initial tension applied to the diaphragm during the first winding of the composite core by the winding machine is obtained; the third initial tension applied to the diaphragm is controlled to decrease linearly, wherein the third initial tension decreases by 2 g / L per turn until the preset third final turn tension is reached.

[0070] In the initial stage of winding, higher tension ensures tight bonding of the multi-layer composite core and eliminates interlayer gaps. However, as the number of winding turns increases and the cell diameter increases, maintaining the initial high tension can lead to excessive clamping stress on the inner layer by the outer layer material, which can easily cause wrinkles in the internal electrode sheets or shedding of the active material. At the same time, since there are differences in the mechanical properties of the positive and negative electrode sheets and the separator, this embodiment controls the tension reduction rate and reduction time in a coordinated manner to ensure that the inner ring is formed with sufficient compactness, while preventing the outer ring from being damaged by excessive tightening. This reduces winding defects caused by tension mismatch, such as serpentine bending of the electrode sheets, uneven stretching of the separator, and excessive ellipticity of the cell.

[0071] For example, Table 7 below shows a tension reference table of the preferred embodiment of the present invention, which includes a first initial tension (applied to the positive electrode, such as 450 gf), a second initial tension (applied to the negative electrode, such as 450 gf) and a third initial tension (applied to the diaphragm, such as 320 gf) applied by the winding machine for every 5 turns of the winding cell.

[0072] Table 7 Tension Reference Table for the Best Embodiment

[0073] In step S203, adhesive is applied to both sides of the wound cell, the wound cell after adhesive application is hot-pressed, and the hot-pressed wound cell is then encapsulated.

[0074] To secure the electrode sheets, related technologies typically add an additional adhesive application mechanism to the winding machine or logistics line. This increases the cost per unit and limits overall efficiency because the adhesive application speed cannot match the production line cycle. Therefore, this embodiment configures an adhesive application mechanism after the winding machine output station. This mechanism can apply adhesive tape to both sides of the cylindrical core after the wound cell comes off the winding needle to wrap and secure it. Specifically, C-type or U-type adhesive can be used. The adhesive application process involves using tape with appropriate adhesion to wrap and adhere along the circumferential direction of the cell end face to bind the outermost separator and electrode sheets of the cell, preventing them from loosening, springing back, or misaligning during subsequent transportation and processing.

[0075] Figure 3(c) shows a schematic diagram of the improved hot-pressing state according to some embodiments of the present invention. After the adhesive is applied, the wound cell enters the hot-pressing process. Hot pressing refers to applying radial pressure to the cylindrical surface of the wound cell under certain temperature, pressure, and time conditions. During the hot pressing process, the heat transferred through the heating plate or hot-pressing roller softens or activates the adhesives on the separator and positive and negative electrode sheets, such as PVDF in the coating of the positive and negative electrode sheets and ceramic layer adhesives on the separator surface. Through hot pressing, the interlayer gaps inside the wound cell are effectively eliminated, the interfacial contact resistance is reduced, and the roundness, diameter consistency, and structural density of the wound cell are improved, resulting in a first intermediate wound cell with a preliminary structural shape.

[0076] After hot pressing, the material of the first intermediate wound cell experiences thermal stress due to temperature changes. Therefore, it is necessary to perform cold pressing on the first intermediate wound cell to eliminate dimensional springback or deformation caused by thermal expansion and contraction. Cold pressing refers to applying radial pressure to the first intermediate wound cell again at room temperature or near room temperature and holding it for a certain period of time. In this embodiment, the cold pressing pressure is adjusted to 4-5 tons, with 5 tons being optimal, and the cold pressing time is adjusted to 4-5 seconds, with 5 seconds being optimal.

[0077] Finally, the first intermediate wound cell, after cold pressing and shaping, is packaged by placing it into a prefabricated battery casing and completing processes such as top cover welding and electrolyte filling port sealing, ultimately obtaining a target wound cell with a complete structure that meets design specifications. The specific steps include the following: An adhesive applicator is installed after the winding machine. The adhesive applicator is used to apply adhesive to both sides of the wound battery cell to fix the wound battery cell. The wound battery cell after adhesive application is hot-pressed to obtain the first intermediate wound battery cell. The first intermediate wound battery cell is cold-pressed and sealed to obtain the target wound battery cell.

[0078] The process of cold-pressing the first intermediate wound cell and encapsulating the cold-pressed first intermediate wound cell to obtain the target wound cell includes: adjusting the cold-pressing pressure and cold-pressing time; cold-pressing the first intermediate wound cell based on the adjusted cold-pressing pressure and cold-pressing time; and encapsulating the cold-pressed first intermediate wound cell to obtain the target wound cell; wherein the cold-pressing pressure is adjusted to a cold-pressing range of 4 to 5 tons and the cold-pressing time is adjusted to a cold-pressing time range of 4 to 5 seconds.

[0079] In this embodiment, an adhesive applicator is installed after the winding machine to bind the end face of the wound battery cell, effectively preventing the interlayer material from loosening and misaligning during transport, providing a stable foundation for subsequent processing. The hot pressing process uses temperature and pressure to soften the bonding material and eliminate interlayer gaps, improving the cell's density, roundness consistency, and interface bonding strength. The subsequent cold pressing process releases the internal stress generated by hot pressing and suppresses dimensional springback, ensuring high stability of the cell's dimensions and shape lock-in. Thus, the entire process chain is tightly connected, effectively avoiding problems such as cell deformation and uneven thickness caused by stress relaxation and interlayer displacement in traditional processes, ultimately improving the dimensional accuracy, structural reliability, and batch consistency of the wound battery cell.

[0080] This embodiment also provides a device for eliminating wrinkles in wound battery cells. This device is used to implement the above embodiments and preferred embodiments, and will not be repeated as already described. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0081] This embodiment provides a device for eliminating wrinkles in wound battery cells, such as... Figure 4 As shown, it includes: The preprocessing module 401 is used to slit and roll the positive electrode sheet, separator and negative electrode sheet to form a composite core.

[0082] The winding module 402 is used to adjust the winding parameters of the winding machine and to wind the composite core on the machine based on the adjusted winding parameters to obtain the wound cell.

[0083] The encapsulation module 403 is used to apply adhesive to both sides of the wound cell, heat-press the wound cell after applying adhesive, and encapsulate the heat-pressed wound cell.

[0084] The winding module 402 is specifically used to obtain the first initial tension applied to the positive electrode sheet when the winding machine performs the first turn of the composite core; and to control the first initial tension applied to the positive electrode sheet to perform a linear decrease, wherein the first initial tension decreases by 2 grams per turn until the preset first tail turn tension is reached.

[0085] The winding module 402 is specifically used to obtain the second initial tension applied to the negative electrode sheet when the winding machine performs the first turn of the composite core; and to control the second initial tension applied to the negative electrode sheet to perform a linear decrease, wherein the second initial tension decreases by 2 grams per turn until the preset second tail turn tension is reached.

[0086] The third initial tension applied to the diaphragm during the first winding of the composite core by the winding machine is obtained; the third initial tension applied to the diaphragm is controlled to decrease linearly, wherein the third initial tension decreases by 2 g / L per turn until the preset third final turn tension is reached.

[0087] The encapsulation module 403 is specifically used to configure an adhesive applicator after the winding machine, and to apply adhesive to both sides of the wound battery cell to fix the wound battery cell.

[0088] The encapsulation module 403 is specifically used to hot-press the glued wound cell to obtain a first intermediate wound cell; to cold-press the first intermediate wound cell and encapsulate the cold-pressed first intermediate wound cell to obtain a target wound cell.

[0089] The encapsulation module 403 is specifically used to adjust the cold pressing pressure and cold pressing time, to cold press the first intermediate wound cell based on the adjusted cold pressing pressure and cold pressing time, and to encapsulate the cold-pressed first intermediate wound cell to obtain the target wound cell; wherein, the cold pressing pressure is adjusted to a cold pressing range of 4 tons to 5 tons and the cold pressing time is adjusted to a cold pressing time range of 4 seconds to 5 seconds.

[0090] In this embodiment, the device for eliminating wrinkles in the wound battery cell is presented in the form of a functional unit. Here, a unit refers to an ASIC circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above-mentioned functions.

[0091] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0092] Figure 5 This is a schematic diagram of the structure of a computer device provided in an embodiment of the present invention.

[0093] The following is a detailed reference. Figure 5 The diagram illustrates a structural schematic suitable for implementing a computer device according to embodiments of the present invention. The computer device may include a processor (e.g., a central processing unit, a graphics processing unit, etc.) 501, which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 502 or a program loaded from memory 508 into random access memory (RAM) 503. RAM 503 also stores various programs and data required for the operation of the computer device. The processor 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0094] Typically, the following devices can be connected to I / O interface 505: input devices 506 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 507 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; memory devices 508 including, for example, magnetic tapes, hard disks, etc.; and communication devices 509. Communication device 509 allows the computer device to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 5 Computer equipment with various devices is shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0095] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 509, or installed from a memory 508, or installed from a ROM 502. When the computer program is executed by the processor 501, it performs the functions defined in the method for eliminating wrinkles in wound battery cells according to embodiments of the present invention.

[0096] Figure 5 The computer device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments of the present invention.

[0097] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that the computer, processor, microprocessor controller, or programmable hardware includes storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the method for eliminating wrinkles in the wound battery cell shown in the above embodiments is implemented.

[0098] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0099] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for eliminating wrinkles in a wound battery cell, characterized in that, The method includes: The positive electrode, separator, and negative electrode are slited and rolled to form a composite core; Adjust the winding parameters of the winding machine, and wind the composite core on the machine based on the adjusted winding parameters to obtain a wound battery cell; Adhesive is applied to both sides of the wound battery cell. The wound battery cell after adhesive application is then subjected to hot pressing and cold pressing, and the cold-pressed wound battery cell is then packaged. During the cold pressing of the wound battery cell, the cold pressing pressure is adjusted to 4 to 5 tons and the cold pressing time is adjusted to 4 to 5 seconds. The adjustment of the winding parameters of the winding machine includes: The first initial tension applied to the positive electrode sheet, the second initial tension applied to the negative electrode sheet, and the third initial tension applied to the separator are obtained when the winding machine performs the first turn of the composite core. The separator flipping tension applied to the separator is set to the range of 180 gf to 250 gf; the values ​​of the first initial tension and the second initial tension are in the range of 400 gf to 500 gf. The first initial tension, the second initial tension, and the third initial tension are controlled to decrease linearly; wherein the first initial tension decreases by 2 grams per revolution until a preset first tail-end tension is reached, the second initial tension decreases by 2 grams per revolution until a preset second tail-end tension is reached, and the third initial tension decreases by 2 grams per revolution until a preset third tail-end tension is reached.

2. The method according to claim 1, characterized in that, The process of applying adhesive to both sides of the wound battery cell includes: An adhesive applicator is installed after the winding machine to apply adhesive to both sides of the wound battery cell in order to fix the wound battery cell.

3. A computer device, characterized in that, include: A memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, the processor executing the computer instructions to perform the method of any one of claims 1 to 2.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the method of any one of claims 1 to 2.

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