Winding device and method for winding battery cell

Abstract

The invention discloses a winding device and method for winding a battery cell, the winding device comprises a positive pole line for conveying a positive pole piece, a negative pole line for conveying a negative pole piece and a turntable for winding the positive pole piece, the negative pole piece and a diaphragm, the positive pole line comprises a positive pole unwinding shaft, an encoder roller, an embossing roller and a control module, the positive pole piece sequentially passes through the encoder roller and the knurling roller from the positive pole unwinding shaft and is guided to the rotating disc, the encoder roller is used for metering the length of the positive pole piece, and the control module is electrically connected with the encoder roller and the knurling roller. And the control module is used for driving the embossing roller to perform embossing operation on the large-surface area of the positive plate according to the lengths of the large-surface area and the R-angle area when the positive plate is wound.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery core winding, and in particular relates to a winding device and method for winding a battery core. Background Art

[0002] At present, most of the wound battery cell production processes add embossing rollers to the positive electrode sheet, so that the surface of the positive electrode sheet changes from the original flat interface to a regularly arranged concave and convex point, and the thickness is also increased compared to before, in order to adjust the misalignment of the tabs and control the gap between the positive and negative electrode sheets. At the same time, there are also cases where the embossing roller is not turned on to prevent the gap between the electrode sheets from being too large after the battery cell is fully charged, resulting in the phenomenon of lithium deposition black spots.

[0003] The embossing roller is turned on throughout the positive electrode sheet, and the entire surface is covered with concave and convex points. The thickness of the positive electrode in the large surface area and the R corner area increases evenly, and the gap between the positive and negative electrodes also increases. After winding, the large surface area is preheated and hot-pressed, which can achieve close fit between the positive and negative electrodes, and provide a convenient channel for lithium ions to move back and forth in the subsequent electrochemical reactions. However, the R corner is an area that the hot press cannot press, and the usual winding method is to reduce the tension circle by circle to ensure that the battery cell electrode / diaphragm will not wrinkle. In this way, the outer circle of the R corner of the core is larger, and the gap between the positive and negative electrodes is larger. In the subsequent electrochemical reaction, during the charge and discharge migration process of Li+, the migration channel of Li+ will become longer due to the large gap between the positive and negative electrodes, resulting in partial failure of reaction at the negative electrode, or Li+ accumulation on the surface to form lithium dendrites. Finally, after the battery cell is fully charged and disassembled, black spots and lithium precipitation appear on the outer circle of the R corner. Summary of the invention

[0004] The purpose of the present invention is to provide a winding device and method for winding battery cells, which can perform zoned stamping on the pole pieces, apply indentations on large surface areas, reserve space for the pole pieces to expand in the later stage, and make the R corner areas that have not been hot-pressed fit tightly, so that the lengths of the lithium ion migration channels between the positive and negative electrodes tend to be consistent, and the negative electrode has a globally stable reaction, which can effectively prevent the generation of black spots and lithium precipitation by chemical reactions in the later stage of the battery cells.

[0005] The technical solution adopted by the present invention to solve its technical problem is to propose a winding device for winding a battery cell, the winding device includes a positive electrode circuit for conveying a positive electrode sheet, a negative electrode circuit for conveying a negative electrode sheet, and a turntable for winding the positive electrode sheet, the negative electrode sheet and the separator, the positive electrode circuit includes a positive electrode unwinding shaft, an encoder roller, an embossing roller and a control module, the positive electrode sheet is guided from the positive electrode unwinding shaft to the turntable through the encoder roller and the embossing roller in sequence, the encoder roller is used to measure the length of the positive electrode sheet, the control module is electrically connected to the encoder roller and the embossing roller, and the control module is used to drive the embossing roller to perform an embossing operation on the large surface area of ​​the positive electrode sheet according to the length of the large surface area and the R angle area of ​​the positive electrode sheet when winding.

[0006] Furthermore, a winding needle is arranged on the turntable, and the positive electrode sheet after the partition stamping is guided onto the winding needle.

[0007] Furthermore, a rubber roller is arranged directly below the embossing roller, and the positive electrode sheet passes between the rubber roller and the embossing roller.

[0008] Furthermore, the embossing roller includes a telescopic structure for driving the embossing roller to rise and fall, and the telescopic structure is electrically connected to the control module. The control module drives the telescopic structure to lower the embossing roller, pressing the positive electrode sheet onto the rubber roller, thereby imprinting an indentation on the positive electrode sheet.

[0009] Furthermore, a metering roller is arranged directly above the encoder roller, and the positive electrode sheet is located between the metering roller and the encoder roller. The encoder roller presses the positive electrode sheet onto the metering roller, so that the positive electrode sheet drives the encoder roller to run synchronously when it runs, and the control module measures the running length of the positive electrode sheet according to the number of rotations of the encoder roller.

[0010] Furthermore, the control module performs zoned embossing on the positive electrode sheet introduced between the embossing roller and the rubber roller according to the length of the large surface area and the R corner area of ​​the positive electrode sheet during winding, so that the indentation exists in the large surface area.

[0011] Furthermore, a transition area is provided at the junction of the R-angle area and the large surface area, and the embossing depth of the embossing roller in the transition area gradually increases from the R-angle area to the large surface area until the embossing depth reaches a maximum value in the large surface area; the embossing depth of the embossing roller in the large surface area is the same.

[0012] The present invention also provides a winding method for a wound battery cell, which is applicable to the winding device for a wound battery cell mentioned above, and the winding method comprises: Obtaining winding parameters, the winding parameters including: the radius of the winding needle configured on the turntable, the thickness of the positive electrode sheet before winding, the thickness of the negative electrode sheet, and the thickness of the separator after hot pressing; Calculating the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters, and outputting them as control parameters for zone stamping of the positive electrode sheet; Based on the control parameters, the embossing roller is driven to perform zone-embossing on the positive electrode sheet, so that the embossed indentations appear alternately on the positive electrode sheet, the alternating interval is the length of the R-angle area of ​​each fold, and the length of the indentations on the positive electrode sheet is the length of the large surface area of ​​each fold.

[0013] Furthermore, the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding is calculated according to the winding parameters, and output as control parameters for zone stamping of the positive electrode sheet, specifically including: Calculate the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters; According to the winding order of the positive electrode sheet, the length of the R corner area and the length of the large surface area of ​​each fold are arranged in sequence; Each length interval belonging to the large surface area is marked to form a marking area, and the marking area is output as a control parameter for partitioning the positive electrode sheet.

[0014] Further, based on the control parameters, the embossing roller is driven to perform zone-by-zone embossing on the positive electrode sheet, specifically comprising: Obtaining the measured length of the positive electrode sheet based on the encoder roller; Determine whether the measured length falls within the marked area: If yes, driving the embossing roller to emboss the positive electrode sheet; If not, the embossing roller does not respond and does not emboss the positive electrode sheet.

[0015] The beneficial effects of the present invention are: The present invention proposes a winding device and method for winding a battery cell. The length of the positive electrode sheet is measured by an encoder, and the positive electrode sheet is embossed in a zoned manner in cooperation with an embossing roller. Indentations are applied to a large surface area to reserve space for the electrode sheet to expand in the later stage. The R corner area that has not been hot-pressed fits tightly, so that the length of the lithium ion migration channel between the positive and negative electrodes tends to be consistent, and the negative electrode reacts globally stably, which effectively prevents the generation of black spots and lithium precipitation due to chemical reactions in the later stage of the battery cell.

[0016] Transition areas are provided on both sides of the junction of the R-angle area and the large surface area, and the indentation in the transition area gradually decreases from the large surface area to the R-angle area. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated into the specification and constitute a part of the specification, illustrate embodiments of the present invention and are used together with the description to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, but not all embodiments. For those of ordinary skill in the art, other drawings can be obtained from these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the layout of a winding device for winding a battery cell according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the positive electrode after partitioning and stamping; Figure 3 Schematic diagram of the division of the large surface area and R corner area of ​​the wound battery cell; Figure 4A schematic diagram showing a comparison between a positive electrode sheet having a transition region and a positive electrode sheet having no transition region; Figure 5 is a structural diagram of the embossing roller; Figure 6 This is a diagram of the roller surface structure of the embossing roller.

[0019] In the figure: 1. Positive electrode unwinding shaft; 2. Encoder roller; 3. Diaphragm roller; 4. Rubber roller; 5. Embossing roller; 6. Indentation; 7. Turntable; 8. First winding needle assembly; 9. Second winding needle assembly; 11. Unwinding roller one; 12. Unwinding roller two; 13. Measuring roller; 41. Auxiliary rubber roller; 51. Auxiliary embossing roller; 71. Guide roller one; 72. Guide roller two. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work. In addition, the design orientation only represents the relative position relationship between the components, not the absolute position relationship.

[0021] In this application, the basic form of battery cell winding and hot pressing is as follows Figure 3 As shown in the figure, after hot pressing, the upper and lower layers of the first circle and the pole piece are bonded together. Figure 3 In order to show the structural characteristics of the subsequent circles, they are not shown strictly.

[0022] In the subsequent turns, the pole pieces at both ends are semicircular, i.e. the R angle area. In this area, the positive pole piece, negative pole piece and separator are all semicircular, and the radius of the semicircles at both ends of the same turn is the same; the middle part is horizontal, i.e. the large surface area. In this area, the positive pole piece, negative pole piece and separator are horizontal, including upper and lower parts, and the length is the same. The wound materials include positive pole piece, separator and negative pole piece.

[0023] See also Figure 1-Figure 6 The embodiment of the present invention provides a winding device for winding a battery cell, the winding device includes a positive electrode circuit for conveying a positive electrode sheet, a negative electrode circuit for conveying a negative electrode sheet, and a turntable 7 for winding the positive electrode sheet, the negative electrode sheet and the separator, wherein the positive electrode circuit includes a positive electrode unwinding shaft 1, an encoder roller 2, an embossing roller 5 and a control module for performing zoned embossing on the positive electrode sheet, the positive electrode sheet is guided from the positive electrode unwinding shaft 1 to the turntable 7 through the encoder roller 2 and the embossing roller 5 in sequence, the encoder roller 2 is used to measure the length of the positive electrode sheet, the control module is electrically connected to the encoder roller 2 and the embossing roller 5, and the control module is used to drive the embossing roller 5 to perform embossing operation on the large surface area of ​​the positive electrode sheet according to the length of the large surface area and the R angle area of ​​the positive electrode sheet when winding.

[0024] For the negative electrode circuit, it is only necessary to introduce the negative electrode sheet into the appropriate position of the turntable 7. The improvement of the winding device in the present application is located on the positive electrode circuit, which is an improvement on the stamping area of ​​the positive electrode sheet. The winding method of the positive electrode sheet, the negative electrode sheet and the diaphragm does not need to be adjusted, and the electrode sheet and the diaphragm can be wound and formed using conventional industry methods.

[0025] Specifically, the turntable 7 is provided with a winding needle, and the positive electrode sheet, the separator and the negative electrode sheet after the partition stamping are introduced onto the winding needle for winding to form a Figure 3 The electrode assembly shown in ; Figure 3 The separator is not shown in the figure, and the separator should be located between the positive electrode sheet and the negative electrode sheet.

[0026] Exemplarily, the turntable 7 is provided with a first winding needle assembly 8 and a second winding needle assembly 9, and the negative electrode sheet, the separator and the positive electrode sheet after partition stamping can be introduced into the first winding needle assembly 8 or the second winding needle assembly 9 for winding; Figure 1 In the figure, the introduction of the first winding needle assembly 8 is taken as an example for demonstration, and the negative electrode circuit can be provided with a negative electrode unwinding shaft, an unwinding roller, and a guide roller. The negative electrode sheet is introduced from the negative electrode unwinding shaft through the unwinding roller and the guide roller in sequence and finally introduced into the first winding needle assembly 8. After the winding needle clamps the electrode sheet and the diaphragm, it can be wound into shape by the self-rotation of the winding needle or the rotation of the turntable 7.

[0027] In the present application, the positive electrode circuit includes a positive electrode unwinding shaft 1, an encoder roller 2, an embossing roller 5 and a control module, wherein an unembossed positive electrode sheet is wound on the positive electrode unwinding shaft 1 for releasing the positive electrode sheet; the encoder roller 2 is used to measure the length of the positive electrode sheet; the embossing roller 5 is used to emboss the positive electrode sheet to form an indentation 6 on the positive electrode sheet; the control module is used to drive the embossing roller 5 to emboss the positive electrode sheet in a partitioned manner according to the measured length of the encoder roller 2, and the embossing object is the large surface area of ​​the positive electrode sheet when it is wound.

[0028] When the positive electrode sheet is wound, there are a large surface area and an R-angle area, which appear alternately and orderly on the positive electrode sheet and are continuous; based on the measured length of the encoder roller 2, when the lengths of the large surface area and the R-angle area of ​​each fold of the positive electrode sheet when wound are known, the embossing roller can be driven to perform embossing operations on the large surface area of ​​the positive electrode sheet according to the lengths of the large surface area and the R-angle area.

[0029] Specifically, the measuring length is the cumulative length, the R corner area and the large surface area appear alternately and continuously, and the length of each area is known. Therefore, when the cumulative length falls in the R corner area, the stamping operation is not performed; when the cumulative length falls in the large surface area, the stamping operation is performed; thus, the partitioned stamping of the positive electrode sheet can be achieved.

[0030] The electrode and the diaphragm are circular after winding, and the circumference of each circle is calculated as πR, where R increases with the number of winding circles, and the increased size is the sum of the thickness of the positive electrode, negative electrode and diaphragm. Due to the existence of the diaphragm, when calculating the circumference of the first circle of the positive electrode, the radius should be the sum of the radius of the winding needle and the thickness of the diaphragm. The increase in radius caused by the thickness of the diaphragm in the first circle (diaphragm thickness c) can be ignored, or it can be defaulted to be increased above the radius of the winding needle. Therefore, the length of the R corner area of ​​the first circle can be recorded as 0.

[0031] After hot pressing, the Figure 3 In the structural form shown in , each circle has a bend on both sides, where the first circle is the first and second folds, the second circle is the third and fourth folds, and so on. It should be clear that after hot pressing, the upper and lower layers of the first circle and the pole piece are bonded together. Figure 3 In order to show the structural characteristics of the subsequent circles, they are not shown strictly.

[0032] In the first circle, the positive plates on the upper and lower sides are basically attached together, and the R angle lengths at both ends can be recorded as 2c or 0. In this application, it is recorded as 0 for calculation. At this time, the first circle only contains two large surfaces, and the perimeter of the first circle is the length of the two large surfaces, that is, the R angle length corresponding to the first fold is 0, and the length of the large surface is half of the perimeter of the first circle; the R angle length corresponding to the second fold is 0, and the length of the large surface is half of the perimeter of the first circle; The second circle includes two large faces and two R corners. The lengths of the two large faces remain unchanged, and the lengths of the two R corners are the same. You only need to calculate the difference between the circumference of the second circle and the circumference of the first circle to get the sum of the two R corner lengths of the second circle, that is, the R corner length corresponding to the second fold is half of the difference, and the length of the large face is half of the circumference of the first circle; the R corner length corresponding to the third fold is half of the difference, and the length of the large face is half of the circumference of the first circle.

[0033] By analogy, the R angle length and large surface length corresponding to each fold can be calculated.

[0034] For example, the radius R of the winding needle can be inferred from the circumference L of the winding needle. At the same time, the basic parameters of the product can be obtained, such as the thickness a of the positive electrode before winding, the thickness b of the negative electrode before winding, and the thickness c of the separator after hot pressing. The circumference of the first circle is calculated to be 2πR, which is divided into the first and second folds after folding, and the length of the large surface is πR, and the length of the R corner area is 0; the circumference of the second circle pole piece is L2=2π(R+a+b+2c), which is divided into the third and fourth folds after folding, and the length of the large surface is still πR, and the length of the R corners on the left and right sides are (L2-L) / 2=π(a+b+2c); the circumference of the third circle pole piece is L3=2π(R+2a+2b+4c), which is divided into the fifth and sixth folds after folding, and the length of the large surface is still πR, and the length of the R corners on the left and right sides are (L3-L) / 2=2π(a+b+2c). By analogy, Appendix 1 can be obtained, and this calculation method can be applied to pole pieces of different models.

[0035] Based on the calculation method in Appendix 1, the R angle length and large surface length of each fold can be obtained. Based on these data, the control module controls the embossing operation of the embossing roller 5 through the metering data of the positive electrode sheet by the encoder roller 2, so as to realize the partitioned embossing / segmented embossing of the positive electrode sheet, emboss the indentation 6 in the large surface area, obtain the desired positive electrode sheet, and wind it with the negative electrode sheet and the diaphragm, finally obtain the desired winding core, realize the formation of the electrode sheet expansion space and the lithium ion migration channel during the subsequent electrochemical reaction of the battery cell.

[0036] In the present application, the length of the positive electrode sheet is measured by the encoder roller 2 to realize the zoned imprinting of the positive electrode sheet. The imprinted indentations 6 appear alternately on the positive electrode sheet, and the alternating interval is the R angle area, such as Figure 2 As shown in; after winding is completed, the indentation 6 exists Figure 3 The large surface area shown in .

[0037] In the positive electrode circuit, a rubber roller 4 may be arranged directly below the embossing roller 5, and the positive electrode sheet passes between the rubber roller 4 and the embossing roller 5; based on this, when the embossing roller 5 is pressed down, the embossing roller 5 presses the positive electrode sheet tightly against the rubber roller 4 to perform the embossing operation; when the embossing roller 5 is lifted up, the embossing roller 5 is separated from the rubber roller 4 and cannot cause an embossing effect on the positive electrode sheet, that is, no embossing operation is performed.

[0038] The rubber roller 4 can be a follow-up type, and the rotation of the embossing roller 5 can be active and driven by a motor. When performing the embossing operation, the embossing roller 5 presses the positive electrode sheet against the rubber roller 4. When the embossing roller 5 rotates, it can drive the positive electrode sheet and the rubber roller 4 to rotate synchronously.

[0039] The embossing roller 5 needs to be pressed down and lifted up relative to the rubber roller 4. A telescopic structure, such as a fixed-stroke cylinder or a telescopic motor, can be configured on the embossing roller 5. When the telescopic length of the telescopic structure increases, the embossing roller 5 is lifted up; when the telescopic length decreases, the embossing roller 5 is pressed down. The telescopic stroke of the telescopic structure can be adjusted according to actual conditions to make the downward pressure and upward lifting distance between the embossing roller 5 and the rubber roller 4 reasonable.

[0040] Specifically, the control module is electrically connected to the telescopic structure. When the embossing operation is performed, the control module drives the telescopic structure to lower the embossing roller 5 and press the positive electrode sheet onto the rubber roller 4, thereby imprinting an indentation 6 on the positive electrode sheet. When the embossing operation is not performed, the control module drives the telescopic structure to raise the embossing roller 5 and separate it from the rubber roller 4. The separation distance is at least the thickness of the positive electrode sheet, and no effective contact is made with the positive electrode sheet.

[0041] In the positive electrode circuit, an auxiliary rubber roller 41 and an auxiliary embossing roller 51 may be provided. The auxiliary embossing roller 51 is located directly below the auxiliary rubber roller 41. The positive electrode sheet passes between the auxiliary rubber roller 41 and the auxiliary embossing roller 51. The auxiliary rubber roller 41 and the auxiliary embossing roller 51 may be located downstream of the rubber roller 4 and the embossing roller 5. Figure 1 Same as the main embossing roller group (rubber roller 4, embossing roller 5), the auxiliary embossing roller group (auxiliary rubber roller 41, auxiliary embossing roller 51) can perform the same function or cooperate with it to implement embossing.

[0042] Of course, the auxiliary embossing roller group can have the same driving structure as the main embossing roller group, and be controlled by the control module to achieve zoned embossing / segmented embossing of the positive electrode sheet.

[0043] In a specific embodiment, two groups of embossing rollers are independently embossed, and the main embossing roller group or the auxiliary embossing roller group can emboss the positive electrode sheet on one side, so that an indentation 6 exists on one side of the positive electrode sheet. At this time, the roller surface structure of the embossing roller 5 can be as follows: Figure 5 , Figure 6 As shown in , the auxiliary embossing roller 51 can be the same. According to the relative position relationship between the two sets of embossing rollers and the positive electrode sheet, the indentation 6 can exist on the front or back of the positive electrode sheet.

[0044] After winding, in a large area, the distances between the negative electrode sheets inside and outside the positive electrode sheet are different. A group of electrode sheets with a smaller distance can be selected as positive and negative electrodes, and corresponding electrode ears can be die-cut on the electrode sheets to make the migration channel of lithium ions shorter.

[0045] In another specific embodiment, two groups of embossing rollers can cooperate to implement embossing, the main embossing roller group embosses the positive side of the positive electrode sheet, so that there is an indentation 6 on the front side of the positive electrode sheet; the auxiliary embossing roller group embosses the back side of the positive electrode sheet, so that there is an indentation 6 on the back side of the positive electrode sheet, and the indentation 6 on the front side and the indentation 6 on the back side appear alternately. Correspondingly, the roller surface structure of the embossing roller 5 is embedded with the roller surface structure of the auxiliary embossing roller 51, for example, the size of the raised parts is the same, but the positions on the roller surface are staggered.

[0046] After winding, in the large area, the distance between the positive electrode sheet and the negative electrode sheet inside and outside the positive electrode sheet is basically the same. The positive and negative electrodes can be selected according to actual needs, and the corresponding pole ears can be die-cut on the electrode sheets.

[0047] In the positive electrode circuit, a metering roller 13 can be arranged directly above the encoder roller 2, and used in conjunction with the encoder roller 2, so that the encoder roller 2 and the positive electrode sheet are always in a tight state. Once the positive electrode sheet runs, it will drive the encoder roller 2 to rotate. The metering roller 13 is a follower type.

[0048] Exemplarily, the positive electrode sheet is located between the metering roller 13 and the encoder roller 2, and the encoder roller 2 presses the positive electrode sheet onto the metering roller 13, so that when the positive electrode sheet runs, it drives the encoder roller 2 to run synchronously, and the rotation of the encoder roller 2 is only affected by the positive electrode sheet. The control module measures the running length of the positive electrode sheet according to the number of rotations of the encoder roller 2, that is, the cumulative length.

[0049] In the present application, the control module performs zone stamping / segment stamping on the positive electrode sheet introduced between the embossing roller 5 and the rubber roller 4 according to the length of the large surface area and the R angle area of ​​the positive electrode sheet during winding, so that the indentation 6 exists on the large surface area. The positive electrode sheet after zone stamping / segment stamping is as follows: Figure 2 as shown in .

[0050] It can be understood that the purpose of zone stamping is to make the migration channel area of ​​lithium ions consistent. Therefore, zone stamping of the positive electrode sheet and zone stamping of the negative electrode sheet can achieve the same effect. Therefore, when the ductility of the material of the negative electrode sheet requires composite stamping, the negative electrode sheet can be zone stamped instead of the positive electrode sheet.

[0051] In the embodiment of the present application, the zonal embossing of the positive electrode sheet by the embossing roller 5 is achieved by lifting the roller body. Since the R-angle area and the large surface area are continuous, there may be less pressure or more pressure when performing the zonal embossing, causing the boundary between the two areas to migrate backwards. Therefore, a transition area can be designed between the two areas to eliminate the migration defect.

[0052] Specifically, a transition area may be set at the junction of the R corner area and the large surface area, and the transition area is implemented based on the R corner area or the large surface area at the junction, wherein: Figure 4(b) in FIG. 1 shows the effect of realizing the transition area in the R corner area. Figure 4 (a) in the figure shows the effect of partition imprinting under ideal conditions.

[0053] The smaller the size of the transition area, the better the effect of the zone stamping. After winding, the spacing between the pole pieces is more stable, and the migration channel of lithium ions tends to be the same at each fold. In order to achieve a better winding effect, the transition area can be designed to be smaller and used as a buffer time for implementing the zone stamping action, achieving a more precise zone stamping control effect.

[0054] In a feasible embodiment, the embossing depth of the embossing roller 5 in the large area is the same, and in the transition area, the embossing depth of the embossing roller 5 in the transition area gradually increases from the R angle area to the large area until the embossing depth reaches a maximum value in the large area.

[0055] The embossing depth can be adjusted by controlling the downward pressure of the embossing roller 5. The embossing force of the embossing roller 5 in the transition area gradually increases from the R angle area to the large surface area until the embossing force reaches the standard value in the large surface area. When the embossing force is the standard value, the embossing depth reaches the maximum value.

[0056] Specifically, when the telescopic structure drives the embossing roller 5 to press down, the pressing force of the telescopic structure can be adjusted based on the metering length. The size of the transition area is preset, and the length on the positive electrode sheet can be 0.5~2mm. The embossing depth (maximum value) can be 10%~30% of the substrate thickness (positive electrode sheet).

[0057] Of course, as an ideal case, the effect of partition imprinting is as follows Figure 4 As shown in (a); when it cannot be achieved Figure 4 In the ideal state shown in (a), the Figure 4 Partition imprinting is performed as shown in (b).

[0058] In the present application, the positive electrode circuit may also be provided with an unwinding roller 11, an unwinding roller 2 12, and a diaphragm roller 3. The unwinding roller 1 is located between the metering roller 13 and the positive electrode unwinding shaft 1. The unwinding roller 2 12 and the diaphragm roller 3 may be arranged in sequence between the metering roller 13 and the rubber roller 4. For specific forms, please refer to Figure 1 .

[0059] When the positive electrode line is connected to the turntable 7, a guide roller 1 71 and a guide roller 2 72 can be configured to guide the angle of the positive electrode sheet entering the turntable. For specific forms, please refer to Figure 1 ; The same applies when the negative line is connected to the turntable 7.

[0060] The present invention also provides a winding method for a wound battery cell, which is applicable to the winding device for a wound battery cell mentioned above, and the winding method comprises: Obtaining winding parameters, the winding parameters including: the radius of the winding needle configured on the turntable, the thickness of the positive electrode sheet before winding, the thickness of the negative electrode sheet, and the thickness of the separator after hot pressing; Calculating the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters, and outputting them as control parameters for zone stamping of the positive electrode sheet; Based on the control parameters, the embossing roller is driven to perform zone-embossing on the positive electrode sheet, so that the embossed indentations appear alternately on the positive electrode sheet, the alternating interval is the length of the R-angle area of ​​each fold, and the length of the indentations on the positive electrode sheet is the length of the large surface area of ​​each fold.

[0061] Among them, the winding parameters are all known data: The radius of the winding needle can be calculated from the circumference of the winding needle, or directly measured. When using winding needles of different models, just match the corresponding radius data; The thickness of the positive electrode sheet is the thickness before winding, which is a known data and can be obtained by measurement or based on product data; The thickness of the negative electrode sheet is the thickness before winding, which is a known data and can be obtained by measurement or based on product data; The thickness of the diaphragm is the thickness of the diaphragm after hot pressing, which is known data and can be obtained through measurement or based on product data.

[0062] In the present application, the calculation method in Appendix 1 can be referred to, and the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding can be calculated based on the winding parameters, so as to perform zone stamping on the positive electrode sheet, leaving an indentation 6 that conforms to the large surface size on the positive electrode sheet, and the interval size between the indentations 6 is the length of the corresponding folded R intersection area.

[0063] In the present application, after obtaining the length of the R angle area and the large surface area of ​​each fold, it can be output as a control parameter for partitioning the positive electrode sheet, so that the control module drives the embossing roller to perform partitioning embossing on the positive electrode sheet based on the metering length, specifically including: Calculate the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters; According to the winding order of the positive electrode sheet, the length of the R corner area and the length of the large surface area of ​​each fold are arranged in sequence to form a number axis; Each length interval belonging to the large surface area is marked on the number axis to form a marking interval, and is output as a control parameter for partitioning the positive electrode sheet.

[0064] In an embodiment of the present application, the measured length is a cumulative value, and the length of the R-angle area of ​​each fold and the length of the large surface area can be arranged in order, and the length interval of the large surface area can be marked, and the interval belonging to the large surface area is marked on the number axis, that is, the marked interval; the marked interval is the distribution interval of multiple large surface areas on the number axis.

[0065] In the present application, after obtaining the winding parameters, the control module can obtain the length of the R angle area and the large surface area of ​​each fold based on the calculation method in Appendix 1, and automatically output them as control parameters; in addition, the maximum number of winding turns can be set to limit it.

[0066] In this application, after obtaining the control parameters, the control module performs zone stamping on the positive electrode sheet according to the control parameters based on the metering length obtained in real time, specifically including: Obtaining the measured length of the positive electrode sheet based on the encoder roller; Determine whether the measured length falls within the marked interval: If yes, driving the embossing roller to emboss the positive electrode sheet; If not, the embossing roller does not respond and does not emboss the positive electrode sheet.

[0067] Exemplarily, the metering length is a cumulative value. When the cumulative value falls within the marked area, it indicates that this is a large surface area and embossing should be performed; when the cumulative value falls outside the marked area, it indicates that this is an R corner area and no embossing is performed.

[0068] After the winding of one battery cell is completed, the accumulated value should also be reset to facilitate the winding of the next battery cell.

[0069] In an embodiment of the present application, when judging whether the measured length falls within the marking interval, a standard unit of pre-operation size can be preset. The pre-operation size is the size of the transition area, such as 0.5~2mm. The area where the pre-operation size is located is the R angle area, which is located on both sides of the large surface area. There are transition areas on both sides of each independent marking interval; the expression on the number axis is: large surface area-transition area-R angle area-transition area-large surface area..., the size of the transition area can be fixed, or change with the size of the R angle area.

[0070] Therefore, the transition area can be marked as a response interval. The length of the response interval is a standard unit of pre-operation size. When the measured length falls within the response interval, the boundary attribute is determined: If the boundary attribute is from the R angle area to the large surface area, the embossing roller is driven to press down gradually; specifically: when the distance between the metering length and the starting boundary value of the marking interval corresponding to the large surface area reaches the pre-operation size, the embossing roller is driven to press down gradually; when the metering length reaches the starting boundary value, the pressing force of the embossing roller reaches the maximum value; A transition region may be formed on the right boundary of the R-corner region, and the height of the indentation in the transition region gradually increases from zero to a maximum value.

[0071] If the boundary attribute is from the large surface area to the R angle area, the embossing roller is driven to be gradually lifted up; specifically, when the metering length reaches the end boundary value of the marking area corresponding to the large surface area, the embossing roller is driven to be gradually lifted up, and when the metering length leaves the end boundary value by a pre-operation dimension, the lifting distance of the embossing roller reaches the maximum value; A transition region may be formed on the left boundary of the R-corner region, and the height of the indentation in the transition region gradually decreases from a maximum value to zero.

[0072] When the size of the R angle area changes, the size of the over-response interval can be adjusted according to the actual situation to reduce the proportion of the transition area in the R angle area, thereby achieving a better winding effect.

[0073] For the height of the indentation, the embossing depth can be adjusted by controlling the downward pressure of the embossing roller 5. The embossing force of the embossing roller 5 in the transition area gradually increases from the R angle area to the large surface area until the embossing force reaches the standard value in the large surface area. When the embossing force is the standard value, the height of the indentation reaches the maximum value.

[0074] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements.

[0075] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementation modes, and it cannot be determined that the specific embodiments of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A winding device for winding a battery cell, the winding device comprising a positive electrode circuit for conveying a positive electrode sheet, a negative electrode circuit for conveying a negative electrode sheet, and a turntable (7) for winding the positive electrode sheet, the negative electrode sheet and the separator, characterized in that: The positive electrode circuit comprises a positive electrode unwinding shaft (1), an encoder roller (2), an embossing roller (5) and a control module. The positive electrode sheet is guided from the positive electrode unwinding shaft (1) to the turntable (7) through the encoder roller (2) and the embossing roller (5) in sequence. The encoder roller (2) is used to measure the length of the positive electrode sheet. The control module is electrically connected to the encoder roller (2) and the embossing roller (5). The control module is used to drive the embossing roller (5) to perform an embossing operation on the large surface area of ​​the positive electrode sheet according to the length of the large surface area and the R angle area of ​​the positive electrode sheet when it is wound.

2. A winding device for winding a battery cell according to claim 1, characterized in that: The turntable (7) is provided with a winding needle, and the positive electrode sheet after the zone stamping is guided onto the winding needle.

3. A winding device for winding a battery cell according to claim 1, characterized in that: A rubber roller (4) is arranged directly below the embossing roller (5), and the positive electrode sheet passes between the rubber roller (4) and the embossing roller (5).

4. A winding device for winding a battery cell according to claim 3, characterized in that: The embossing roller (5) comprises a telescopic structure for driving the embossing roller (5) to rise and fall, the telescopic structure being electrically connected to the control module, the control module driving the telescopic structure to lower the embossing roller (5), pressing the positive electrode sheet onto the rubber roller (4), thereby imprinting an indentation (6) on the positive electrode sheet.

5. A winding device for winding a battery cell according to claim 4, characterized in that: A metering roller (13) is arranged directly above the encoder roller (2), and the positive electrode sheet is located between the metering roller (13) and the encoder roller (2). The encoder roller (2) presses the positive electrode sheet onto the metering roller (13), so that when the positive electrode sheet is running, it drives the encoder roller (2) to run synchronously, and the control module measures the running length of the positive electrode sheet according to the number of rotations of the encoder roller (2).

6. A winding device for winding a battery cell according to claim 5, characterized in that: The control module performs zoned embossing on the positive electrode sheet introduced between the embossing roller (5) and the rubber roller (4) according to the length of the large surface area and the R angle area of ​​the positive electrode sheet when it is wound, so that the indentation (6) exists in the large surface area.

7. A winding device for winding a battery cell according to claim 1, characterized in that: A transition area is provided at the junction of the R-angle area and the large surface area, and the embossing depth of the embossing roller (5) in the transition area gradually increases from the R-angle area to the large surface area until the embossing depth reaches a maximum value in the large surface area; the embossing depth of the embossing roller (5) in the large surface area is the same.

8. A winding method for a wound battery cell, characterized in that: A winding device for winding a battery cell according to any one of claims 1 to 7, wherein the winding method comprises: Obtaining winding parameters, the winding parameters including: the radius of the winding needle configured on the turntable, the thickness of the positive electrode sheet before winding, the thickness of the negative electrode sheet, and the thickness of the separator after hot pressing; Calculating the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters, and outputting them as control parameters for zone stamping of the positive electrode sheet; Based on the control parameters, the embossing roller is driven to perform zone-embossing on the positive electrode sheet, so that the embossed indentations appear alternately on the positive electrode sheet, the alternating interval is the length of the R-angle area of ​​each fold, and the length of the indentations on the positive electrode sheet is the length of the large surface area of ​​each fold.

9. A winding method for a wound battery cell according to claim 8, characterized in that: The length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding is calculated according to the winding parameters, and output as control parameters for partitioning and stamping the positive electrode sheet, specifically including: Calculate the length of the R corner area and the large surface area of ​​each fold of the positive electrode sheet after winding according to the winding parameters; According to the winding order of the positive electrode sheet, the length of the R corner area and the length of the large surface area of ​​each fold are arranged in sequence to form a number axis; Each length interval belonging to the large surface area is marked on the number axis to form a marking interval, and is output as a control parameter for partitioning the positive electrode sheet.

10. A winding method for a wound battery cell according to claim 9, characterized in that: Driving the embossing roller to emboss the positive electrode sheet in different areas based on the control parameters specifically includes: Obtaining the measured length of the positive electrode sheet based on the encoder roller; Determine whether the measured length falls within the marked interval: If yes, driving the embossing roller to emboss the positive electrode sheet; If not, the embossing roller does not respond and does not emboss the positive electrode sheet.

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