Method for correcting dislocation of tabs of wound battery cell and wound battery cell

Abstract

The invention discloses a winding cell tab dislocation correction method, which comprises the following steps of: obtaining a first position parameter of a cell tab in a cell winding direction, taking a first tab arranged in the cell winding direction as a reference tab, arranging tabs arranged behind the reference tab into a tab group according to an arrangement sequence, each tab group comprises two tabs, namely a 2n tab and a (2n + 1) tab; obtaining the dislocation interval between the reference tab and each (2n + 1) th tab, and calculating the tolerance of the dislocation interval; and based on the tolerance, adjusting the distance between the (2n + 1) th tab and the reference tab in the winding direction of the battery cell, and obtaining a second position parameter of the corrected tab. According to the method for correcting the dislocation of the tabs of the wound battery cell, die cutting parameters needing to be adjusted are calculated according to the dislocation interval between the tabs on an original battery cell, a new pole piece is obtained through die cutting by using the adjusted die cutting parameters, and the new pole piece can be used for winding a new battery cell with the tabs on the two sides aligned.

Description

Technical Field

[0001] The invention relates to the technical field of battery manufacturing, and in particular to a method for correcting misalignment of a pole ear of a wound battery cell and a wound battery cell. Background Art

[0002] New energy lithium batteries are committed to improving the rate charging and discharging performance, aiming to enhance battery efficiency and accelerate the charging process to cope with the growing high energy demand. However, in the process of pursuing this goal, the insufficient current capacity at the root of the pole ear has become a bottleneck problem that needs to be solved urgently. To this end, the industry has proposed the use of a single-turn bipolar ear winding method as a response strategy. The single-turn bipolar ear winding method requires that the pole ears of each layer be aligned as much as possible to facilitate subsequent pole ear welding. However, during the implementation process, it was found that the pole ear misalignment phenomenon was more serious in the single-turn bipolar ear winding method, that is, the pole ear areas of different layers deviated, resulting in difficulties in the subsequent pole ear welding steps. Summary of the invention

[0003] In order to overcome the defects in the prior art, the present invention provides a method for correcting the misalignment of the pole ears of a wound battery cell and a wound battery cell. The method for correcting the misalignment of the pole ears of a wound battery cell calculates the die-cutting parameters that need to be adjusted according to the misalignment interval between the pole ears on the original battery cell, and uses the adjusted die-cutting parameters to die-cut new pole pieces. The new pole pieces can be used to wind a new battery cell with the pole ears on both sides aligned.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a method for correcting the misalignment of the pole lug of a wound battery cell, comprising the following steps: Obtaining a first position parameter of the cell tab in the cell winding direction, taking the first tab arranged in the cell winding direction as a reference tab, and arranging the tabs arranged behind the reference tab into tab groups according to the arrangement order, each tab group including two tabs, namely the 2nth tab and the 2n+1th tab; Obtaining the misalignment interval between the reference pole lug and each 2n+1 pole lug, and calculating the tolerance of the misalignment interval; Based on the tolerance, the distance between the 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell is adjusted to obtain the second position parameter of the corrected pole tab.

[0005] Through the above scheme, the tolerance is calculated according to the misalignment interval between the tabs on the battery cell, and the positions of the tabs are uniformly adjusted according to the tolerance, so that the tabs on at least one side of the battery cell are aligned after the adjustment.

[0006] Further, obtaining the misalignment interval between the second pole lug and each 2n-th pole lug in the battery cell where the pole piece is at the second position parameter, and calculating the tolerance of the misalignment interval; Based on the tolerance, while ensuring that the distance between each 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell remains unchanged, the distance between the 2nth pole tab and the reference pole tab in the winding direction of the battery cell is adjusted to obtain the third position parameter of the corrected pole tab.

[0007] While adjusting the distance between the 2nth pole ear and the reference pole ear in the winding direction of the battery cell, it is necessary to ensure that the distance between the 2n+1th pole ear and the reference pole ear in the winding direction of the battery cell remains unchanged, that is, the position of the 2nth pole ear is adjusted between the 2n+1th pole ear and the 2n-1th pole ear, and after the adjustment, at least the pole ears on both sides of the battery cell are aligned.

[0008] Furthermore, the offset interval between the reference pole lug and the second pole lug in the battery cell with the pole piece in the third position parameter is obtained, and under the condition that the distance between each 2n+1 pole lug and each 2n pole lug in the battery cell winding direction and the reference pole lug remains unchanged, the offset interval between the reference pole lug and the second pole lug is subtracted from the distance between the second pole lug and the reference pole lug in the battery cell winding direction to obtain the third position parameter of the corrected pole lug. When adjusting the distance between the second pole lug and the reference pole lug in the battery cell winding direction, it is necessary to ensure that the distance between each 2n+1 pole lug and each 2n pole lug in the battery cell winding direction and the reference pole lug remains unchanged. After adjustment, the pole lugs on both sides of the battery cell are aligned.

[0009] Further, along the winding direction of the battery cell, the offset interval between the reference electrode and each 2n+1 electrode is positive, and against the winding direction of the battery cell, the offset interval between the reference electrode and each 2n+1 electrode is negative; Along the winding direction of the battery cell, the offset interval between the second pole tab and each 2n pole tab is positive, and against the winding direction of the battery cell, the offset interval between the second pole tab and each 2n pole tab is negative. The moving direction of the pole tab is adjusted by controlling the positive or negative offset interval to ensure the accuracy of the adjustment.

[0010] Furthermore, the offset interval is the distance between the same ends of the two tabs in the length direction of the battery cell.

[0011] Further, the steps of calculating the tolerance of the misalignment interval include: Obtain the offset intervals between the reference tab and each 2n+1th tab, which are S1, S2, S n , the calculation formula of the tolerance d of the misalignment interval is: d=2×(S n -n×S1) / (n×(n-1)).

[0012] Further, adjusting the distance between the 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell includes: Calculate the distance that needs to be adjusted for the 2n+1th tab in the winding direction of the battery cell, that is, the compensation value B of the 2n+1th tabn = the offset distance between the reference pole tab and the third pole tab + (n-1) d; The distance between the 2n+1th tab and the reference tab in the winding direction of the battery cell is subtracted from the compensation value B. n .

[0013] After adjusting the distances between the 2n pole tab and the 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell, the die-cutting parameters of the pole piece are corrected according to the final position parameters, so that the die-cut pole pieces can be wound into battery cells with fully aligned pole tabs.

[0014] Further, the step of obtaining the offset interval between the reference pole lug and each 2n+1 pole lug includes measuring the offset interval between the reference pole lug and each 2n+1 pole lug using a film ruler; The step of obtaining the offset interval between the second pole lug and each 2n pole lug includes measuring the offset interval between the second pole lug and each 2n pole lug using a film ruler.

[0015] A wound battery cell corrected using the above method comprises a stacked and wound positive electrode sheet, a separator and a negative electrode sheet, wherein the pole ears of the positive electrode sheet are distributed on both sides of the width direction of the wound battery cell, and the pole ears of the positive electrode sheet on both sides are aligned in the width direction of the wound battery cell, and the pole ears of the negative electrode sheet are distributed on both sides of the width direction of the wound battery cell, and the pole ears of the negative electrode sheet on both sides are aligned in the width direction of the wound battery cell.

[0016] Furthermore, the die-cutting parameters of the electrode sheet are adjusted according to the third position parameter, and both the positive electrode sheet and the negative electrode sheet are obtained by die-cutting using the adjusted die-cutting parameters.

[0017] By means of the above technical solution, the beneficial effects of the present invention are as follows: The present application calculates the die-cutting parameters that need to be adjusted based on the misaligned intervals between the pole ears on the original battery cell, and uses the adjusted die-cutting parameters to die-cut new pole pieces. The new pole pieces can be used to wind new battery cells with the pole ears on both sides aligned.

[0018] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a flow chart of a method for correcting misalignment of a winding battery cell tab in an embodiment of the present invention; Figure 2 is a schematic diagram of die-cutting parameters in an embodiment of the present invention; Figure 3 Schematic diagram of the winding structure of the original positive electrode sheet and the original negative electrode sheet in an embodiment of the present invention; Figure 4 Schematic diagram of the winding structure of the new positive electrode sheet and the new negative electrode sheet in the embodiment of the present invention.

[0021] The figure marks of the above drawings are: 1, first pole ear; 2, second pole ear; 3, third pole ear; 10, original positive electrode sheet; 11, first pole ear group; 12, second pole ear group; 20, original negative electrode sheet. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0024] Example: Combination Figure 1-4 As shown, this embodiment discloses a method for correcting misalignment of a winding battery cell tab, comprising the following steps: Obtain die-cutting parameters of an original pole piece, the original pole piece having a first end and a second end, a first pole lug being provided on the original pole piece and at a preset distance from the first end, the first pole lug being assumed to be a reference pole lug 1, and a first pole lug group 11, a second pole lug group 12, and an nth pole lug group being provided on the original pole piece along the reference pole lug 1 toward the second end, each of the pole lug groups comprising a 2nth pole lug and a 2n+1th pole lug. The die-cutting parameters include the spacing between the reference pole lug 1 and each 2n+1th pole lug, the spacing between adjacent pole lug groups, and the distance between the 2nth pole lug and the 2n+1th pole lug in each pole lug group.

[0025] The distance between adjacent pole lug groups is the distance between the 2n+1th pole lugs in each pole lug group, that is, the distance between two adjacent 2n+1th pole lugs.

[0026] Obtaining the offset interval between the reference pole tab and the 2n+1th pole tab in each pole tab group in the original battery cell formed by winding the original pole sheet; Calculate the tolerance d of the misalignment interval between the reference tab and the 2n+1th tab in each tab group; Compensation value B of the 2n+1th tab n = the offset distance between the reference pole tab and the third pole tab + (n-1) d; Adjust the die-cutting parameters, subtract the offset interval between the reference pole ear and the third pole ear 3 from the spacing between the reference pole ear and the third pole ear 3, and subtract the compensation value B of the 2n+1 pole ear from the spacing between the 2n+1 pole ear and the 2n-1 pole ear. n ; The first pole piece is cut out of the film according to the adjusted die-cutting parameters and wound up to obtain a first battery cell with at least one side of the pole ears aligned.

[0027] Obtaining a dislocation interval between a second electrode tab in a first battery cell and a 2nth electrode tab in each electrode tab group; Calculating the tolerance D of the misalignment interval between the second tab and the 2nth tab in each tab group; Compensation value E of the second tab in each tab group n = the offset distance between the second pole tab of the second pole tab group and the second pole tab of the third pole tab group + (n-1) D; Adjust the die-cutting parameters, and under the premise of ensuring that the spacing between adjacent tab groups remains unchanged, subtract the compensation value E of the second tab in the nth tab group from the distance between the second tab and the third tab in the nth tab group. n .

[0028] In a feasible embodiment, the original positive electrode sheet 10 is cut out using the original die-cutting parameter film, such as Figure 2 As shown, the original positive electrode sheet 10 has a first end and a second end, and the original positive electrode sheet 10 is provided with a reference electrode ear, a second electrode ear...ath electrode ear arranged at intervals from the first end to the second end, and the original die-cutting parameters include a1, a2...a c , and A1, A2…A j , where j = (c+1) / 2 (c is an odd number greater than 1). a1 and A1 both represent the distance between the reference pole ear and the first end of the original pole piece. c Represents the distance between two adjacent tabs, A j Represents the distance between two adjacent 2n+1 pole lugs; The original negative electrode sheet 20 is cut out of the film with the original die-cutting parameters, wherein the original negative electrode sheet 20 has a first end and a second end, and the original negative electrode sheet 20 is provided with a reference electrode ear, a second electrode ear, and a cth electrode ear arranged at intervals from the first end to the second end, and the original die-cutting parameters include g1, g2, and g c , and G1, G2…G j, where j = (c+1) / 2 (c is an odd number greater than 1), g1 and G1 both represent the distance between the reference pole ear and the first end of the original pole piece, g c Represents the distance between two adjacent tabs, G j Represents the distance between two adjacent 2n+1th pole lugs.

[0029] The original positive electrode sheet 10, the separator and the original negative electrode sheet 20 are stacked and wound into an original battery cell, such as Figure 3 As shown, in the original state of the battery cell, the misalignment interval between the reference pole ear and the 2n+1 pole ear in the original positive electrode sheet 10 is obtained. In a feasible embodiment, a film ruler is used to measure the misalignment interval between the second pole ear and the 2n+1 pole ear, which are S1, S2...S m , m = (c-1) / 2 (c is an odd number greater than or equal to 3); Obtain the offset interval between the reference tab and the 2n+1 tab in the original negative electrode sheet 20. In a feasible embodiment, a film ruler is used to measure the offset interval between the second tab and the 2n+1 tab, which are E1, E2, E3, E4, E5, E6, E7, E8, E9, E10, E111, E12, E13, E14, E15, E16, E17, E18, E19, E20, E21, E22, E3 m , m = (c-1) / 2 (c is an odd number greater than or equal to 3); Among them, the misalignment interval is the distance between the same ends of the two pole tabs in the length direction of the battery cell. Along the winding direction of the battery cell, the misalignment interval between the reference pole tab and the 2n+1 pole tab is positive, and against the winding direction of the battery cell, the misalignment interval between the reference pole tab and the 2n+1 pole tab is negative.

[0030] Calculate S1 to S m Tolerance d: d=2×(S m -m×S1) / (m×(m-1)); Calculate the misalignment compensation value of the 2n+1th tab in the positive electrode sheet: B c =S1+(m-1)d; Here, c is an odd number greater than or equal to 3.

[0031] Calculate E1 to E m Tolerance f: f=2×(E m -m×E1) / (m×(m-1)); Calculate the misalignment compensation value of the 2n-1th tab in the negative electrode sheet: H c =E1+(m-1)f; Here, c is an odd number greater than or equal to 3.

[0032] The adjusted first die-cutting parameters are as follows: In the first positive electrode sheet: keep the distance between the 2n+1th pole ear and the previous pole ear unchanged, adjust the distance between the 2nth pole ear and the previous pole ear, so that the distance between the two adjacent 2n+1th pole ears in the first die-cutting parameter satisfies A j '=A j +B c (c is an odd number greater than or equal to 3); In the first negative electrode sheet: keep the distance between the 2n+1th pole ear and the previous pole ear unchanged, adjust the distance between the 2nth pole ear and the previous pole ear, so that the distance between the two adjacent 2n+1th pole ears in the first die-cutting parameter satisfies G j '=G j +H c (c is an odd number greater than or equal to 3); The positive and negative electrodes cut from the film using the first die-cutting parameter are wound into the first battery cell: Obtain the offset intervals between the second pole tab and the 2n pole tab of the positive electrode sheet in the first battery cell, which are P1, P2, ...P k ; k = (c-2) / 2, (c is an odd number greater than or equal to 4); Get the offset intervals between the second pole tab and the 2n pole tab of the negative electrode sheet in the first battery cell, which are Q1, Q2, ... Q k , k = (c-2) / 2, (c is an odd number greater than or equal to 4).

[0033] Among them, along the winding direction of the battery cell, the offset interval between the second pole tab and the 2n pole tab is positive, and against the winding direction of the battery cell, the offset interval between the second pole tab and the 2n pole tab is negative.

[0034] Calculate P1 to P k Tolerance D: D = 2 × (P k -k×P1) / (k×(k-1)); Calculate the misalignment compensation value of the 2nth tab in the positive electrode sheet: B c =P1+(k-1)D; Wherein, c is an even number greater than or equal to 4; Calculate Q1 to Q k Tolerance F: F=2×(Q k -k×Q1) / (k×(k-1)); Calculate the misalignment compensation value of the 2nth tab in the negative electrode sheet: H c =Q1+(k-1)F; Here, c is an even number greater than or equal to 4.

[0035] The adjusted second die-cutting parameters are as follows: In the positive electrode sheet, the distance between the two adjacent 2n+1 pole tabs is kept unchanged, and the distance between the 2n pole tab and the previous pole tab is adjusted to satisfy the distance a between the 2n pole tab and the previous pole tab. c '=a c +B c (c is an even number greater than or equal to 4), the distance between the first odd-numbered pole lug and the previous pole lug is equal to the distance between two adjacent odd-numbered pole lugs minus the distance between the previous odd-numbered pole lug and the even-numbered pole lug between the two odd-numbered pole lugs.

[0036] In the negative electrode sheet, keep the distance between two adjacent odd-numbered tabs unchanged, and adjust the distance between the 2nth tab and the previous tab to satisfy the distance a between the 2nth tab and the previous tab. c '=a c +H c (c is an even number greater than or equal to 4), the distance between the first odd-numbered pole lug and the previous pole lug is equal to the distance between two adjacent odd-numbered pole lugs minus the distance between the previous odd-numbered pole lug and the even-numbered pole lug between the two odd-numbered pole lugs.

[0037] The positive and negative electrodes cut from the film using the second die-cutting parameter are wound into the second battery cell: Obtain the offset interval C between the second pole ear and the first pole ear of the positive electrode sheet in the second battery cell, adjust the die-cutting parameter a2'=a2+C of the second pole ear in the positive electrode sheet, keep other die-cutting parameters unchanged, and cut out a new positive electrode sheet; Obtain the offset interval c between the second pole tab and the first pole tab of the negative electrode sheet in the second battery cell, adjust the die-cutting parameter g2'=g2+c of the second pole tab in the negative electrode sheet, keep other die-cutting parameters unchanged, and cut out a new negative electrode sheet.

[0038] By winding a new positive electrode sheet, a separator and a new negative electrode sheet, a Figure 4 A new cell is shown with both tabs aligned.

[0039] Embodiment 2 discloses a wound battery cell obtained after correction using the above method, comprising a stacked and wound positive electrode sheet, a separator and a negative electrode sheet, wherein the electrode ears of the positive electrode sheet are distributed on both sides of the width direction of the wound battery cell, and the electrode ears of the positive electrode sheet on both sides are aligned in the width direction of the wound battery cell, and the electrode ears of the negative electrode sheet are distributed on both sides of the width direction of the wound battery cell, and the electrode ears of the negative electrode sheet on both sides are aligned in the width direction of the wound battery cell.

[0040] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for correcting the misalignment of a winding battery cell tab, characterized in that: The following steps are involved: Obtaining a first position parameter of the cell tab in the cell winding direction, taking the first tab arranged in the cell winding direction as a reference tab, and arranging the tabs arranged behind the reference tab into tab groups according to the arrangement order, each tab group including two tabs, namely the 2nth tab and the 2n+1th tab; Obtaining the misalignment interval between the reference pole lug and each 2n+1 pole lug, and calculating the tolerance of the misalignment interval; Based on the tolerance, the distance between the 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell is adjusted to obtain the second position parameter of the corrected pole tab.

2. The method for correcting misalignment of a winding battery cell tab according to claim 1, characterized in that: Also includes Obtaining the misalignment interval between the second pole lug and each 2n-th pole lug in the battery cell where the pole piece is at the second position parameter, and calculating the tolerance of the misalignment interval; Based on the tolerance, while ensuring that the distance between each 2n+1th pole tab and the reference pole tab in the winding direction of the battery cell remains unchanged, the distance between the 2nth pole tab and the reference pole tab in the winding direction of the battery cell is adjusted to obtain the third position parameter of the corrected pole tab.

3. The method for correcting misalignment of a winding battery cell tab according to claim 2, characterized in that: Also includes Obtain the offset interval between the reference pole lug and the second pole lug in the battery cell with the pole piece in the third position parameter; under the condition that the distance between each 2n+1 pole lug and each 2n pole lug and the reference pole lug in the battery cell winding direction remains unchanged, subtract the offset interval between the reference pole lug and the second pole lug from the distance between the second pole lug and the reference pole lug in the battery cell winding direction to obtain the corrected third position parameter of the pole lug.

4. The method for correcting misalignment of a winding battery cell tab according to claim 3, characterized in that: Along the winding direction of the battery cell, the offset interval between the reference electrode tab and each 2n+1 electrode tab is positive, and against the winding direction of the battery cell, the offset interval between the reference electrode tab and each 2n+1 electrode tab is negative; Along the winding direction of the battery cell, the offset interval between the second pole tab and each 2n pole tab is positive, and against the winding direction of the battery cell, the offset interval between the second pole tab and each 2n pole tab is negative.

5. The method for correcting misalignment of a winding battery tab according to any one of claims 1 to 3, characterized in that: The offset interval is the distance between the same ends of the two tabs in the length direction of the battery cell.

6. The method for correcting misalignment of a winding battery cell tab according to claim 4, characterized in that: The steps to calculate the tolerance of the misalignment interval include: Obtain the offset intervals between the reference tab and each 2n+1th tab, which are S1, S2, S n , the calculation formula of the tolerance d of the misalignment interval is: d=2×(S n -n×S1) / (n×(n-1))。 7. The method for correcting misalignment of a winding battery cell tab according to claim 6, characterized in that: The steps of adjusting the distance between the 2n+1th tab and the reference tab in the winding direction of the battery cell based on the tolerance include: Calculate the distance that needs to be adjusted for the 2n+1th tab in the winding direction of the battery cell, that is, the compensation value B of the 2n+1th tab n = the offset distance between the reference pole tab and the third pole tab + (n-1) d; The distance between the 2n+1th tab and the reference tab in the winding direction of the battery cell is subtracted from the compensation value B. n .

8. The method for correcting misalignment of a winding battery cell tab according to claim 7, characterized in that: The step of obtaining the offset interval between the reference pole lug and each 2n+1th pole lug comprises measuring the offset interval between the reference pole lug and each 2n+1th pole lug using a film ruler; The step of obtaining the offset interval between the second pole lug and each 2n pole lug includes measuring the offset interval between the second pole lug and each 2n pole lug using a film ruler.

9. A wound battery cell obtained by modification using any one of the methods of claims 3 to 8, characterized in that: It includes stacked and wound positive electrode sheets, separators and negative electrode sheets, wherein the tabs of the positive electrode sheets are distributed on both sides of the width direction of the wound battery cell, and the tabs of the positive electrode sheets on both sides are aligned in the width direction of the wound battery cell, and the tabs of the negative electrode sheets are distributed on both sides of the width direction of the wound battery cell, and the tabs of the negative electrode sheets on both sides are aligned in the width direction of the wound battery cell.

10. The wound battery cell according to claim 9, characterized in that: The die-cutting parameters of the electrode sheet are adjusted according to the third position parameter, and both the positive electrode sheet and the negative electrode sheet are obtained by die-cutting using the adjusted die-cutting parameters.

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