A negative electrode sheet for wide-width silicon-based battery cell and a method for preparing a wide-width silicon-based battery cell

Abstract

The present application provides a method for preparing a negative electrode sheet for a wide-width silicon-based battery cell and a wide-width silicon-based battery cell. The method for preparing a negative electrode sheet for a wide-width silicon-based battery cell comprises the following steps: S1, providing a current collector, on which a reserved tab area is set; S2, coating the surface of the current collector on both sides of the reserved tab area with a slurry and drying it, to obtain a pole roll having a first coating area and a second coating area; S3, cutting the pole roll to obtain the negative electrode sheet. The method of the embodiment of the present invention forms a pole roll having a first coating area and a second coating area by coating on both sides of the reserved tab area of ​​the current collector, so that the two ends of the pole roll after baking have the same degree of deformation, and then in the process, the first coating area and the second coating area on both sides of the reserved tab area can maintain the tension balance at both ends of the pole roll, thereby reducing the breakage of the roller, the folding and wrinkling of the tab in the process, and improving the yield and the pass rate.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a negative electrode sheet for a wide-width silicon-based battery cell and a method for preparing the wide-width silicon-based battery cell. Background Art

[0002] In recent years, wide-width power batteries have become a research hotspot due to their high energy density. Silicon-based negative electrodes, due to their high specific capacity, have become a sought-after target for high-energy-density batteries. Currently, wide-width battery cell electrodes are often coated in a one-out-one manner due to their wide width. This leads to widespread cracking, edge wrinkling, and tape breakage during the coating-roller separation-laser cutting / die-cutting-lamination process. Furthermore, negative electrodes with wrinkled tabs are prone to burrs and short circuits caused by metal wire during laser cutting, resulting in very low process throughput and production efficiency. Summary of the Invention

[0003] In view of this, the present invention provides a method for preparing a large-width negative electrode sheet for silicon-based battery cells, which can solve the problems of large-width negative electrode sheets for silicon-based batteries being prone to cracking, edge wrinkling and tape breakage during the manufacturing process.

[0004] The present invention also provides a method for preparing a large-width silicon-based battery cell.

[0005] The method for preparing a negative electrode sheet for a large-width silicon-based battery cell according to the first embodiment of the present invention comprises the following steps:

[0006] S1, providing a current collector, wherein a reserved tab area is set on the current collector;

[0007] S2, coating the slurry on the surface of the current collector on both sides of the reserved tab area and drying the slurry to obtain a pole coil having a first coating area and a second coating area;

[0008] S3, cutting the electrode coil to obtain the negative electrode sheet.

[0009] Furthermore, in step S2, the slurry is coated on both sides of the reserved tab area on the front and back sides of the current collector.

[0010] Furthermore, in step S2, the coating speed is 2 m / min to 60 m / min.

[0011] Furthermore, the width of the blank area at the edge of the pole roll is 2mm-4mm.

[0012] Furthermore, step S3 includes:

[0013] S31, rolling the pole coil;

[0014] S32, performing laser cutting on the electrode coil after rolling in the reserved electrode tab area to form a plurality of electrode tabs in the reserved electrode tab area;

[0015] S33 , die-cutting the electrode roll formed with the plurality of electrode tabs along the length direction to divide the electrode roll into a plurality of negative electrode sheets, wherein each negative electrode sheet includes a first coating area, an electrode tab, and a second coating area.

[0016] Furthermore, in the step S31, the pole coil is cut into pieces after rolling to remove the blank area.

[0017] Furthermore, the reserved tab area is close to one side edge of the current collector, and the first coating area is located at the one side edge of the current collector.

[0018] According to the second embodiment of the present invention, a method for preparing a large-width silicon-based battery cell includes the following steps:

[0019] S100, providing a positive electrode sheet, a separator, and a negative electrode sheet, wherein the negative electrode sheet is prepared according to the method according to any one of claims 1 to 8;

[0020] S200, stacking the positive electrode sheet, the separator, and the negative electrode sheet in sequence to obtain a laminate, wherein the tabs on the negative electrode sheet are located outside the separator and the positive electrode sheet in a vertical direction;

[0021] S300 , cutting the stacked body, removing the outer portion of the tab, and obtaining a battery cell.

[0022] Furthermore, the reserved tab area is located in the middle of the current collector, and the width of the reserved tab area after step S31 is equivalent to the width of two tabs.

[0023] Wherein, in the step S200, the corresponding areas in the vertical direction of the first coating area and the second coating area are overlapped,

[0024] In the step S300 , cutting is performed from the middle of the reserved tab area to obtain two battery cells.

[0025] Furthermore, the reserved tab area is close to one side edge of the current collector, and the first coating area is located at the one side edge of the current collector.

[0026] Wherein, in the step S200, corresponding areas are overlapped in the vertical direction of the second coating area,

[0027] In the step S300 , cutting is performed at the boundary between the first coating area and the reserved tab area to remove the first coating area to obtain the battery cell.

[0028] The above technical solution of the present invention has at least one of the following beneficial effects:

[0029] According to the method for preparing a negative electrode sheet for a wide-width silicon-based battery cell according to an embodiment of the present invention, a reserved tab area is first set on the current collector, and then the slurry is coated on the current collector surface on both sides of the reserved tab area and dried to obtain a pole roll having a first coating area and a second coating area. Finally, the pole roll is cut and processed to obtain a negative electrode sheet. In other words, a pole roll having a first coating area and a second coating area is formed by coating on both sides of the reserved tab area of ​​the current collector, so that the two ends of the pole roll have the same degree of deformation after baking. Then, during the manufacturing process, the first coating area and the second coating area on both sides of the reserved tab area can maintain the tension balance at both ends of the pole roll, thereby reducing the roller breakage, the folding and wrinkling of the tab during the manufacturing process, and improving the yield and the pass rate.

[0030] Moreover, in the preparation method of large-width silicon-based battery cells, the second coating area is retained during the rolling, laser cutting, die-cutting and lamination processes, and the outer part of the tab is cut off after the positive electrode sheet, diaphragm and negative electrode sheet are laminated, thereby avoiding the breakage of the tape during the roller, the folding and wrinkling of the tab during the process, and greatly reducing the burrs caused by the wrinkles of the tab during laser cutting, thereby reducing the short circuit rate and improving the process capability.

[0031] In addition, corresponding areas are overlapped in the vertical direction of the second coating area, and at the same time, cutting is performed from the junction of the first coating area and the reserved tab area to remove the first coating area, thereby forming a wide silicon-based battery cell, which improves the process pass rate, has high efficiency, a simple method, and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a pole coil after coating according to an embodiment of the present invention;

[0033] Figure 2 This is a schematic structural diagram of a slit pole coil according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic structural diagram of a pole coil after laser cutting according to an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of the structure of the negative electrode sheet after die-cutting according to one embodiment of the present invention

[0036] Figure 5 This is a schematic top view of the structure of a laminated body after lamination according to one embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the main structure of a laminated body after lamination according to one embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the structure of a battery cell after laser cutting and separation according to an embodiment of the present invention;

[0039] Figure 8 This is a flow chart of the preparation process of a large-width silicon-based battery cell according to an embodiment of the present invention.

[0040] Figure numerals: 100. Negative electrode sheet; 110. Reserved tab area; 111. Tab; 121. First coating area; 122. Second coating area; 130. Blank area; 200. Positive electrode sheet; 300. Separator. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the described embodiments of the present invention, all other embodiments derived by persons of ordinary skill in the art are within the scope of protection of the present invention.

[0042] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0043] The following combination Figure 1-4 The following describes a method for preparing a negative electrode sheet for a wide silicon-based battery cell according to an embodiment of the present invention.

[0044] The method for preparing a negative electrode sheet for a large-width silicon-based battery cell according to the first embodiment of the present invention comprises the following steps:

[0045] S1, providing a current collector, wherein a reserved tab area 110 is set on the current collector;

[0046] S2, coating the slurry on the current collector surfaces on both sides of the reserved tab area 110 and drying the slurry to obtain a pole coil having a first coating area 121 and a second coating area 122;

[0047] S3 , cutting the electrode coil to obtain the negative electrode sheet 100 .

[0048] That is, firstly, a reserved tab area 110 is set on the current collector, and then the slurry is coated on the current collector surface on both sides of the reserved tab area 110 and dried to obtain a pole coil having a first coating area 121 and a second coating area 122. Finally, the pole coil is cut to obtain the negative electrode sheet 100. In other words, as Figure 1 As shown, by the reserved tab area 110 on both sides of the current collector (corresponding to Figure 1 The left and right sides of the pole coil are coated to form a pole coil having a first coating area 121 and a second coating area 122, so that the two ends of the pole coil have the same degree of deformation after baking. In the process, the first coating area 121 and the second coating area 122 located on both sides of the reserved pole ear area 110 can maintain the tension balance at both ends of the pole coil, thereby reducing the breakage of the roller during the process, the folding and wrinkling of the pole ear 111, and improving the yield and pass rate.

[0049] The preparation method of the negative electrode sheet for a large-width silicon-based battery cell in an embodiment of the present invention forms a pole roll having a first coating area 121 and a second coating area 122 by coating on both sides of the reserved pole tab area 110 of the current collector, thereby ensuring that the two ends of the pole roll have the same degree of deformation after baking. Furthermore, during the process, the first coating area 121 and the second coating area 122 on both sides of the reserved pole tab area 110 can maintain the tension balance at both ends of the pole roll, reduce the breakage of the strip during the roller, the folding and wrinkling of the pole tab 111, and improve the yield and pass rate.

[0050] The above S1-S3 are described in detail below.

[0051] First, step S1 is described, namely providing a current collector.

[0052] The current collector can be, for example, at least one of copper foil and carbon-coated copper foil. That is, based on a comprehensive consideration of material performance and cost, copper foil or carbon-coated copper foil can be selected as the current collector, and a reserved tab region 110 is provided on the current collector, and the reserved tab region 110 is provided along the length of the current collector.

[0053] Next, step S2, namely, preparing the pole coil, will be described.

[0054] In some embodiments, the slurry is applied on both sides of the reserved tab area 110 on both the front and back sides of the current collector. That is, the reserved tab area 110 is provided on both the front and back sides of the current collector, and the slurry is applied on both sides of the two reserved tab areas 110, respectively, thereby forming a first coating area 121 and a second coating area 122 on both sides of the reserved tab area 110 on the front and back sides of the pole coil. This can further maintain the tension balance at both ends of the pole coil, greatly reduce the phenomenon of roller breakage, folding and wrinkling of the tab 111 during the process, and further improve the yield rate and first pass rate.

[0055] Furthermore, the coating speed is 2m / min to 60m / min. That is, the coating speed can be, for example, 2m / min, 10m / min, 20m / min, 30m / min, 40m / min, 50m / min, or 60m / min. By controlling the coating speed, the electrical performance and reliability of the negative electrode sheet for wide-width silicon-based battery cells can be improved. When the coating speed is less than 2m / min, the coating speed is low and the production efficiency is low. When the coating speed is greater than 60m / min, the coating speed is high, which is not conducive to forming a uniformly thick coating area and is prone to forming defects such as holes in the coating area.

[0056] Furthermore, the width of the blank area 130 at the edge of the pole roll is 2mm-4mm. Figure 1 As shown, during coating, for example, 2mm, 3mm, and 4mm margins 130 can be provided on both sides of the pole coil, respectively. By reducing the margins 130, the tension at both ends of the pole coil can be further balanced, further reducing roller breakage, folding, and wrinkling of the pole tabs 111. The width of the margins 130 should not be too large. Excessively wide margins 130 can affect the electrical performance and reliability of wide-width silicon-based battery cells and hinder the maintenance of balanced tension at both ends of the pole coil.

[0057] Next, step S3 , ie, preparing the negative electrode sheet 100 , will be described.

[0058] In some embodiments, step S3 includes:

[0059] S31, rolling the pole coil;

[0060] S32, performing laser cutting on the electrode coil after rolling in the reserved electrode tab area 110 to form a plurality of electrode tabs 111 in the reserved electrode tab area 110;

[0061] S33 , die-cutting the electrode roll with the plurality of electrode tabs 111 along the length direction to divide the electrode roll into a plurality of negative electrode sheets 100 , wherein each negative electrode sheet 100 includes a first coating area 121 , an electrode tab 111 , and a second coating area 122 .

[0062] That is, firstly, the performance of the pole coil is further improved by rolling; then, the reserved pole lug area 110 of the rolled pole coil is laser cut, such as Figure 3 As shown, after laser cutting, multiple tabs 111 can be formed in the reserved tab area 110; finally, the pole roll with multiple tabs 111 is die-cut along the length direction to form multiple negative electrode sheets 100. The number of negative electrode sheets 100 should be consistent with the number of tabs 111, as shown in FIG. Figure 4As shown, each negative electrode sheet 100 includes a first coating area 121, a tab 111, and a second coating area 122. Since the first coating area 121 and the second coating area 122 are formed on the electrode coil, the tension at both ends of the electrode coil can be balanced during the process of preparing the negative electrode sheet 100 through rolling, laser cutting, and die cutting. This reduces the risk of tape breakage during rolling and the folding and wrinkling of the tab 111, further improving the yield and first pass rate.

[0063] Furthermore, in step S31, the pole coil is cut after rolling to remove the blank area 130. Figure 2 As shown, the blank area 130 on the electrode roll is removed by slitting to obtain the negative electrode sheet 100 of theoretical width.

[0064] As one embodiment of the present invention, the reserved tab area 110 can be located in the middle of the current collector, and the width of the reserved tab area 110 after step S31 is equivalent to the width of the two tabs 111, and the first coating area 121 is equivalent to the width of the second coating area 122. In other words, the reserved tab area 110 is set in the middle of the current collector, and the reserved tab area 110 is designed to be twice as wide, thereby forming a first coating area 121 and a second coating area 122 of equivalent width. Then, after die-cutting, two negative electrode sheets 100 with the same coating area and tabs 111 are formed, thereby achieving a one-out-two coating method and improving production efficiency.

[0065] As another embodiment of the present invention, the reserved tab area 110 is close to one side edge of the current collector, and the first coating area 121 is located at one side edge of the current collector. Figure 1 As shown, the reserved tab area 110 and the first coating area 121 are set at the edge of the current collector (corresponding to Figure 1 On the left side of the current collector), after coating, a second coating area 122 with a larger width and a first coating area 121 with a smaller width can be obtained, so that a large-width negative electrode sheet 100 and a small-width negative electrode sheet 100 can be formed after die-cutting. By arranging a small-sized first coating area 121 on one side edge of the current collector, the yield and the pass rate of the large-width negative electrode sheet 100 in the process can be improved.

[0066] The following combination Figure 5-8 The method for preparing a large and wide silicon-based battery cell according to an embodiment of the present invention is described. The method for preparing a large and wide silicon-based battery cell according to an embodiment of the second aspect of the present invention comprises the following steps:

[0067] S100, providing a positive electrode sheet 200, a separator 300, and a negative electrode sheet 100, wherein the negative electrode sheet 100 is obtained according to the method for preparing a negative electrode sheet for a wide-width silicon-based battery cell according to the first embodiment;

[0068] S200 , stacking the positive electrode sheet 200 , the separator 300 , and the negative electrode sheet 100 in sequence to obtain a laminate, wherein the tab 111 on the negative electrode sheet 100 is located outside the separator 300 and the positive electrode sheet 200 in the vertical direction;

[0069] S300 , cutting the laminate, removing the outer portion of the tab 111 , and obtaining a battery cell.

[0070] That is to say, if Figure 8 As shown, in step S100, a negative electrode sheet 100 is prepared by the method for preparing a negative electrode sheet for a wide-width silicon-based battery cell according to the first embodiment of the above-mentioned embodiment, and the prepared negative electrode sheet 100 is applied to the method for preparing a wide-width silicon-based battery cell, which can reduce the breakage of the roller during the manufacturing process and improve the yield and the pass rate of the wide-width silicon-based battery cell in the manufacturing process; in step S200, the positive electrode sheet 200, the diaphragm 300, and the negative electrode sheet 100 are stacked in sequence to obtain a stack, and the tab 111 on the negative electrode sheet 100 and the outer part of the tab 111 are stacked on the outside; in step S300, the outer part of the tab 111 of the stack is cut off to obtain a battery cell, that is, after obtaining the stack, the first coating area 121 or the second coating area 122 is separated and cut off, which can avoid the folding and wrinkling of the tab 111 during the manufacturing process and greatly reduce the burrs caused by the wrinkling of the tab 111 during laser cutting. Here, it should be noted that there is no special limitation on the positive electrode sheet 200 and the separator 300 , and they can be prepared using conventional methods.

[0071] As an embodiment of the present invention, the reserved tab area 110 is located in the middle of the current collector, and the width of the reserved tab area 110 after step S31 is equivalent to the width of the two tabs 111, and the width of the first coating area 121 is equivalent to the width of the second coating area 122. In step S200, the corresponding areas in the vertical direction of the first coating area 121 and the second coating area 122 are overlapped, and in step S300, the reserved tab area 110 is cut from the middle to obtain two battery cells. That is to say, the reserved tab area 110 is set in the middle of the current collector, and the width of the reserved tab area 110 is set to the width of the two tabs 111, and the width of the first coating area 121 is equivalent to the width of the second coating area 122, so that two negative electrode sheets 100 with the same coating area and tabs 111 can be formed after die-cutting; then in step S200, the positive electrode sheet 200, the diaphragm 300 and the negative electrode sheet 100 with the first coating area 121, and the positive electrode sheet 200, the diaphragm 300 and the negative electrode sheet 100 with the second coating area 122 are stacked in sequence in the vertical direction of the first coating area 121 and the second coating area 122, so as to obtain two identical stacks; finally, in step S300, cutting is performed from the middle of the reserved tab area 110 to separate the two stacks, thereby obtaining two battery cells. That is to say, by forming a first coating area 121 and a second coating area 122 with consistent width on both sides of the reserved tab area 110, and performing laser cutting after lamination to separate the stacked body with the first coating area 121 and the stacked body with the second coating area 122, it is possible to reduce the folding and wrinkling of the tab 111 of the negative electrode sheet 100 during the manufacturing process, as well as the burrs caused by the wrinkles of the tab 111 during laser cutting, and realize a one-out-two coating method to improve production efficiency.

[0072] As another embodiment of the present invention, the reserved tab area 110 is close to one side edge of the current collector, and the first coating area 121 is located at one side edge of the current collector, wherein, in step S200, the corresponding areas are overlapped in the vertical direction of the second coating area 122, and in step S300, cutting is performed from the intersection of the first coating area 121 and the reserved tab area 110 to remove the first coating area 121 and obtain a battery cell. That is to say, the reserved tab area 110 is set at the edge of the current collector, and then after coating, a larger width second coating area 122 and a smaller width first coating area 121 can be obtained, so that a large width negative electrode sheet 100 and a small width negative electrode sheet 100 can be formed after die-cutting; then in step S200, as Figure 5 、 Figure 6 As shown, the positive electrode sheet 200, the separator 300 and the negative electrode sheet 100 having the second coating area 122 are sequentially stacked in the vertical direction of the first coating area 121 and the second coating area 122, thereby obtaining a laminate; finally, in step S300, as shown Figure 7As shown, cutting is performed from the boundary between the first coating area 121 and the reserved tab area 110 to remove the first coating area 121 and obtain a wide battery cell. In other words, by setting the first coating area 121 and the reserved tab area 110 on one side edge of the current collector, a wide negative electrode sheet 100 with a second coating area 122 is obtained as much as possible, and then laser cutting is performed after lamination to remove the first coating area 121. This not only reduces the folding and wrinkling of the tab 111 of the negative electrode sheet 100 during the manufacturing process, as well as the burrs caused by the wrinkles of the tab 111 during laser cutting, but also obtains a wide battery cell and improves the yield and pass rate when manufacturing the wide battery cell.

[0073] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0074] The following first describes in detail the silicon negative electrode components, coating area width, blank area width, tab width, coating speed, and laser cutting speed of Examples 1-2 and Comparative Example 1, and tests the coating pass rate of the negative electrode sheet and the pass rate after core stacking under the above parameter conditions. The results are shown in Table 1.

[0075] Table 1 Process parameters of wide-width silicon-based battery cells and the pass rate of negative electrode coating and the pass rate after core stacking

[0076]

[0077] As can be seen from Table 1, compared with Comparative Example 1, by coating the pole rolls having the first coating area 121 and the second coating area 122 on both sides of the reserved pole lug area of ​​the current collector, the coating pass rate and the core stacking pass rate of Example 1 and Example 2 are much higher than those of Comparative Example 1. This is because by forming the pole rolls having the first coating area 121 and the second coating area 122, the two ends of the pole rolls after baking can have the same degree of deformation, and then in the process, the first coating area 121 and the second coating area 122 located on both sides of the reserved pole lug area 110 can maintain the tension balance at both ends of the pole roll, thereby reducing the breakage of the roller, the folding and wrinkling of the pole lugs in the process, thereby improving the coating pass rate and the core stacking pass rate. As can be seen from Table 1, the coating speed and laser cutting speed corresponding to the high first pass rate of Examples 1 and 2 are also much greater than the coating speed and laser cutting speed of Comparative Example 1. This shows that the method for preparing a negative electrode sheet for a wide silicon-based battery cell according to Examples 1-2 of the present invention can achieve a high first pass rate at a high coating speed and a high laser cutting speed. In other words, the method for preparing a negative electrode sheet for a wide silicon-based battery cell according to the embodiment of the present invention also has the advantage of high production efficiency.

[0078] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a wide silicon-based battery cell for a laminated battery cell, characterized in that: The steps include: S1, providing a current collector, wherein a reserved tab area is set on the current collector; S2, coating the slurry on the surface of the current collector on both sides of the reserved tab area and drying the slurry to obtain a pole roll having a first coating area and a second coating area, wherein the reserved tab area is close to one side edge of the current collector, the first coating area is located at the one side edge of the current collector, and the first coating area and the second coating area are asymmetrically distributed; S3, cutting the electrode coil to obtain a negative electrode sheet; S100, providing a positive electrode sheet, a separator, and the negative electrode sheet; S200, stacking the positive electrode sheet, the separator, and the negative electrode sheet in sequence to obtain a laminate, wherein the tabs on the negative electrode sheet are located outside the separator and the positive electrode sheet in a vertical direction; S300 , cutting the stacked body, removing the outer portion of the tab, and obtaining a battery cell.

2. The method according to claim 1, characterized in that In the step S2, the slurry is coated on both sides of the reserved tab area on the front and back sides of the current collector.

3. The method according to claim 2, characterized in that In step S2, the coating speed is 2 m / min to 60 m / min.

4. The method according to claim 2, characterized in that The width of the blank area at the edge of the pole roll is 2mm-4mm.

5. The method according to claim 4, characterized in that The step S3 comprises: S31, rolling the pole coil; S32, performing laser cutting on the electrode coil after rolling in the reserved electrode tab area to form a plurality of electrode tabs in the reserved electrode tab area; S33 , die-cutting the electrode roll formed with the plurality of electrode tabs along the length direction to divide the electrode roll into a plurality of negative electrode sheets, wherein each negative electrode sheet includes a first coating area, an electrode tab, and a second coating area.

6. The method according to claim 5, characterized in that In the step S31 , the pole coil is cut into pieces after rolling to remove the blank area.

7. The method according to claim 1, characterized in that The reserved tab area is located in the middle of the current collector, and the width of the reserved tab area after step S31 is equivalent to the width of two tabs. Wherein, in the step S200, the corresponding areas in the vertical direction of the first coating area and the second coating area are overlapped, In the step S300 , cutting is performed from the middle of the reserved tab area to obtain two battery cells.

8. The method according to claim 7, characterized in that The reserved tab area is close to one side edge of the current collector, and the first coating area is located at the one side edge of the current collector. Wherein, in the step S200, corresponding areas are overlapped in the vertical direction of the second coating area, In the step S300 , cutting is performed at the boundary between the first coating area and the reserved tab area to remove the first coating area to obtain the battery cell.

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