Tab die cutting method and battery
By calculating the width and height of the electrode tabs of each ring of the battery cell, and using a die-cut method with gradient enlargement trend, the problem of unevenness of the ear tap is solved, and the coverage of the ear tip and battery performance of the battery end face are improved.
Patent Information
- Application Number
- CN202411965811.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-18
AI Technical Summary
In battery production, the problem of folding outward or uneven flattening is prone to occur during the horizontal process of the extreme ear, which leads to the inner ring of the battery end surface without the pole ear covering, increasing the risk of welding short circuit, and affecting battery performance and yield.
By calculating the width and height of the electrode tabs of each ring of the battery cell to be processed, the electrode ears are processed using a die-cut method of gradient enlargement to ensure the coverage of the electrode ears on the end surface of the battery cell.
It effectively improves the coverage after the polar ear pad is flat, avoids welding short circuits, and improves battery performance and production yield.
Smart Images
Figure CN119839958A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of battery manufacturing, and in particular to a tab die-cutting method and a battery. Background Art
[0002] In battery production, tab forming technology is one of the key steps to ensure battery performance and safety, and its technological progress directly affects the overall performance of the battery.
[0003] In the related technology, the battery tab forming mainly includes two stages: laser die cutting and flattening. After the tab is cut into the designed size and shape by laser die cutting equipment, the tab flattening equipment uses mechanical force to fold the tab inward and flatten it onto the end face of the battery cell for subsequent welding.
[0004] However, during the flattening process, the tabs may fold outward or be flattened unevenly, resulting in the inner circle of the battery end face not being covered by the tabs. In this way, when the tabs are subsequently welded, it is easy to weld through the diaphragm of the inner circle of the battery cell and cause a short circuit, thereby affecting the performance of the battery and reducing the yield rate. Summary of the invention
[0005] In view of this, the present application provides a tab die-cutting method and a battery, which can increase the coverage of the tab on the end face of the battery, improve battery performance, and increase the yield rate of battery production.
[0006] This application specifically adopts the following technical solutions:
[0007] On the one hand, the present application provides a tab die cutting method, the method comprising:
[0008] According to the cell parameters of the cell to be processed, the width and height of the pole tabs of each circle of the pole piece in the cell to be processed are calculated, wherein the cell parameters include the cell diameter, the pole piece thickness, the diaphragm thickness and the total number of pole tabs, wherein the width and height of the pole tabs of each circle of the pole piece in the cell to be processed respectively increase in a gradient from the inner circle to the outer circle of the cell to be processed;
[0009] The tabs of the battery cell to be processed are die-cut according to the calculated tab widths and tab heights of the pole pieces of each circle.
[0010] Optionally, the calculating, according to the cell parameters of the cell to be processed, the tab width and tab height of each electrode ring in the cell to be processed comprises:
[0011] According to the battery cell parameters, determine the radius R of the i-th circle electrode i And the number of tabs N i , 1≤i≤t, where t is the total number of windings of the electrode sheet in the battery cell to be processed, t≥2, and the electrode sheet of the tth winding is located at the outermost winding of the battery cell to be processed;
[0012] According to the radius R of the i-th pole piece i And the number of tabs N i , the electrode thickness and the diaphragm thickness, calculate the ear width W of the i-th circle electrode i and the tab height H i .
[0013] Optionally, the radius R of the pole piece of the i-th circle i And the number of tabs N i , the electrode thickness and the diaphragm thickness, calculate the ear width W of the i-th circle electrode i and the tab height H i ,include:
[0014] According to the radius R of the i-th pole piece i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ;
[0015] According to the radius R of the i-th pole piece i , at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i .
[0016] Optionally, the cell diameter includes the diameter of the central hole of the cell to be processed, and the diaphragm thickness includes the thickness of the pre-rolled diaphragm;
[0017] When i=1, the radius R of the pole piece of the i-th circle i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include:
[0018] Determine the radius R1 of the first circle of pole pieces according to the diameter of the central hole of the battery cell to be processed, the thickness of the pre-rolled diaphragm and the thickness of the pole piece;
[0019] Calculate the circumference C1 of the first circle of pole pieces according to the radius R1 of the first circle of pole pieces;
[0020] The width W1 of the pole lugs of the first circle of pole pieces is determined according to the circumference C1 of the first circle of pole pieces and the number N1 of the pole lugs of the first circle of pole pieces.
[0021] Optionally, the width W1 of the pole piece of the first circle is calculated using the following formula:
[0022]
[0023] Among them, R1 is the radius of the first circle of pole pieces; d is the diameter of the center hole of the battery cell to be processed; T0 is the thickness of the pole piece; T1 is the thickness of the pre-rolled diaphragm; C1 is the circumference of the first circle of pole pieces; N1 is the number of pole ears of the first circle of pole pieces.
[0024] Optionally, the diaphragm thickness comprises a single-layer diaphragm thickness;
[0025] When i>1, the radius R of the pole piece of the i-th circle i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include:
[0026] According to the radius R of the i-1th pole piece i-1 , the thickness of the single-layer diaphragm and the thickness of the pole piece, determine the radius R of the pole piece of the i-th circle i ;
[0027] According to the radius R of the i-th pole piece i , calculate the circumference C of the i-th pole piece i ;
[0028] According to the circumference C of the i-th pole piece i and the number of pole lugs N of the pole piece of the i-th circle i , determine the width W of the pole ear of the i-th pole piece i .
[0029] Optionally, the diaphragm thickness comprises a pre-rolled diaphragm thickness;
[0030] When i=1, the radius R of the pole piece of the i-th circle i , at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i ,include:
[0031] The tab height H1 of the first circle of pole pieces is calculated according to the thickness of the pre-rolled diaphragm and the thickness of the pole piece.
[0032] Optionally, the pole lug height H1 of the first circle of pole pieces is calculated using the following formula:
[0033] H1=T0+T1
[0034] Among them, T0 is the thickness of the pole piece; T1 is the thickness of the pre-rolled diaphragm.
[0035] Optionally, the diaphragm thickness comprises a single-layer diaphragm thickness;
[0036] When i>1, the radius R of the pole piece of the i-th circle i, at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i ,include:
[0037] According to the radius R of the i-th pole piece i , and the height H of the pole ear of the i-1th pole piece i-1 , calculate the pole ear height H of the i-th pole piece i ;
[0038] Among them, the radius R of the i-th circle pole piece i The calculation is performed using the following formula:
[0039]
[0040] Wherein, d is the diameter of the center hole of the battery cell to be processed; T0 is the thickness of the electrode; T1 is the thickness of the pre-rolled diaphragm.
[0041] Optionally, when i>1, the pole ear height H of the i-th pole piece is i The calculation is performed using the following formula:
[0042] H i =2T0+2T1+μH i-1
[0043] Wherein, μ is the overlap coefficient, 0<μ≤1 / 2.
[0044] Another aspect of the present application provides a battery, wherein the battery comprises a battery cell, and the tabs of the battery cell are processed by the tab die-cutting method described in the previous aspect.
[0045] The lug die-cutting method and battery provided in the embodiment of the present application calculate the lug width and lug height of each circle of pole pieces in the battery cell to be processed according to the battery cell diameter, pole piece width, diaphragm thickness and total number of lugs, so that the lug width and lug height of each circle of pole pieces in the battery cell to be processed, respectively, show a gradient increasing trend from the inner circle to the outer circle of the battery cell to be processed. By die-cutting such lugs with a gradient width and height, the situation where the lugs fold outward after being flattened can be effectively improved, so that the entire end face of the battery cell is covered with lugs, so that when the lugs are subsequently welded, it is not easy to weld through the diaphragm of the inner circle of the battery cell to cause a short circuit. Therefore, the lug die-cutting method and battery provided in the embodiment of the present application improve the performance of the battery and improve the yield rate of battery production. BRIEF DESCRIPTION OF THE DRAWINGS
[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0047] Figure 1 It is a flow chart of a tab die cutting method provided in an embodiment of the present application;
[0048] Figure 2 is a flow chart of another tab die cutting method provided in an embodiment of the present application;
[0049] Figure 3 is a flow chart for calculating the width of the pole lugs on the pole pieces of the first circle provided in an embodiment of the present application;
[0050] Figure 4 is a flow chart for calculating the width of the pole lug on the pole piece of the i-th circle provided in an embodiment of the present application, where i>1;
[0051] Figure 5 It is a schematic diagram of a die-cutting route for a pole ear on a pole piece by a cutting knife provided in an embodiment of the present application.
[0052] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0054] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0055] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.
[0056] The present application embodiment provides a tab die cutting method, which is generally applied to batteries with tabs. Figure 1 As shown, the tab die cutting method comprises:
[0057] Step 110: Calculate the tab width and tab height of each electrode circle in the battery cell to be processed according to the battery cell parameters of the battery cell to be processed.
[0058] Among them, the battery cell parameters include battery cell diameter, pole piece thickness, diaphragm thickness and the total number of pole tabs; from the inner circle to the outer circle of the battery cell to be processed, the pole tab width and pole tab height of each circle of pole pieces show a gradient increasing trend.
[0059] Step 120: Die-cut the tabs of the battery cell to be processed according to the calculated tab widths and tab heights of the pole pieces of each circle.
[0060] The tab die-cutting method provided in the embodiment of the present application can effectively improve the situation where the tab folds outward after being flattened by die-cutting the tab with a gradually changing width and height, so that the entire end surface of the battery cell is covered with the tab, so that when the tab is subsequently welded, it is not easy to weld through the diaphragm of the inner circle of the battery cell to cause a short circuit. Therefore, the tab die-cutting method and battery provided in the embodiment of the present application improve the performance of the battery and increase the yield rate of battery production.
[0061] Figure 2 : is a flow chart of a tab die cutting method provided in an embodiment of the present application, such as Figure 2 As shown, the tab die-cutting method is generally applied to batteries with tabs, and includes the following steps:
[0062] Step 210: Obtain battery cell parameters.
[0063] In this embodiment, the battery cell parameters include the battery cell diameter, the electrode piece thickness, the diaphragm thickness and the total number of electrode tabs.
[0064] Among them, the cell diameter includes the outer diameter and the inner diameter of the cell. The outer diameter of the cell can be determined according to the specifications of the cell to be processed; the inner diameter of the cell refers to the diameter of the center hole of the cell to be processed, and the diameter of the center hole is generally equal to the diameter of the core shaft used to wind the cell on the battery winding machine.
[0065] The electrode sheet thickness refers to the thickness of the electrode sheet where the electrode tab to be die-cut is located. Generally speaking, the battery cell has a positive electrode sheet and a negative electrode sheet, the thickness of the positive electrode sheet and the negative electrode sheet are equal, and the positive electrode sheet has a positive electrode tab, and the negative electrode sheet has a negative electrode tab.
[0066] The thickness of the diaphragm includes the thickness of the pre-rolled diaphragm and the thickness of the single-layer diaphragm. The pre-rolled diaphragm refers to the diaphragm that is pre-wound on the mandrel during the winding process of the lithium battery. The pre-rolled diaphragm is used to ensure that the diaphragm will not be offset or misplaced during the subsequent winding process. Generally speaking, without considering the deformation of the pre-rolled diaphragm, the thickness of the pre-rolled diaphragm is equal to the product of the thickness of the single-layer diaphragm and the number of pre-rolled turns. However, in the actual pre-rolling process, the pre-rolled diaphragm may be deformed due to stretching, resulting in a reduction in the thickness of the single-layer diaphragm. Therefore, in this embodiment, the thickness of the pre-rolled diaphragm is taken as a separate parameter.
[0067] Step 220: Determine the radius R of the ith electrode according to the cell parameters. i And the number of tabs N i .
[0068] Wherein, 1≤i≤t. t is the total number of windings of the electrode sheet in the battery cell to be processed, and t≥2. In the embodiment of the present application, for the convenience of the following description, it is considered that the first electrode sheet is the innermost electrode sheet of the battery cell to be processed, and the tth electrode sheet is the outermost electrode sheet of the battery cell to be processed.
[0069] Based on the obtained battery cell parameters, the radius R of each circle of pole piece can be calculated separately i , and the number of pole ears N on each pole piece i Among them, the radius R of each circle of pole piece i The number of tabs N on each circle of pole pieces can be determined based on the inner diameter of the battery cell, the thickness of the pole piece and the thickness of the diaphragm. i It can be determined based on the cell outer diameter and the total number of tabs in the cell parameters.
[0070] Optionally, on each circle of pole pieces of the battery cell to be processed, the number of pole lugs on the outer circle of pole pieces is greater than the number of pole lugs on the inner circle of pole pieces, and the difference in the number of pole lugs between two adjacent circles of pole pieces is a preset number. Exemplarily, the preset number is 2 to 3.
[0071] Therefore, according to the outer diameter of the battery cell, the thickness of the pole lugs and the thickness of the diaphragm, the total number of windings of the pole piece in the battery cell to be processed can be calculated; according to the total number of windings of the pole piece and the relationship between the number of pole lugs between two adjacent pole pieces mentioned above, the number of pole lugs N on each pole piece can be determined. i For example, the number of pole tabs N on each pole piece can be i It is regarded as an arithmetic progression, and then the number of pole ears N on each pole piece is calculated according to the total number of pole ears and the total number of windings of the pole piece. i ; Alternatively, the number of pole lugs on the first circle of pole pieces can be determined based on the total number of pole lugs and the total number of winding turns, and then the number of pole lugs on the other circles of pole pieces can be determined in turn based on the number of pole lugs N1 on the first circle of pole pieces, and the number of pole lugs on each circle of pole pieces can be adaptively adjusted according to actual needs.
[0072] Step 230: according to the radius R of the pole piece of the i-th circle i And the number of tabs N i , pole piece thickness and diaphragm thickness, calculate the pole ear width W of the i-th pole piece i and the tab height H i .
[0073] Among them, the width of the pole ear of the i-th circle pole piece is W i , according to the radius R of the i-th pole piece i And the number of tabs N i The corresponding calculation is carried out to obtain the height H of the pole ear of the pole piece of the i-th circle. i , according to the radius R of the i-th pole piece i , at least one of the electrode thickness and the diaphragm thickness, is obtained by performing corresponding calculations.
[0074] Next, the embodiment of the present application will analyze the width W of the pole ear of the pole piece of the i-th circle for the two cases of i=1 and i>1. i The calculation methods are explained in detail.
[0075] like Figure 3 As shown, when i = 1, according to the radius R of the pole piece of the i-th circle i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include:
[0076] Step 310: Determine the radius R1 of the first circle of pole pieces according to the diameter of the center hole of the battery cell to be processed, the thickness of the pre-rolled diaphragm, and the thickness of the pole piece.
[0077] The first circle pole piece is the innermost circle pole piece, and its radius R1 can be calculated using the following formula:
[0078]
[0079] Among them, d is the diameter of the center hole of the battery cell to be processed, that is, the inner diameter of the battery cell; T0 is the thickness of the electrode; T1 is the thickness of the pre-rolled diaphragm.
[0080] Step 320: Calculate the circumference C1 of the first circle of pole pieces according to the radius R1 of the first circle of pole pieces.
[0081] Specifically, the circumference C1 of the first circle of pole pieces can be calculated using the following formula:
[0082] C1=2πR1
[0083] Step 330 : Determine the width W1 of the lugs of the first circle of pole pieces according to the circumference C1 of the first circle of pole pieces and the number N1 of the lugs of the first circle of pole pieces.
[0084] Generally speaking, the multiple pole ears on each circle of pole pieces are evenly distributed circumferentially on the circle of pole pieces, and the two are separated by a cutting (die-cutting) process, which can reduce the unevenness of current density and avoid the risk of local overheating and short circuit, while also helping to improve the charging and discharging efficiency and life of the battery.
[0085] Therefore, the following calculation formula can be used to calculate the ear width W1 of the first circle of pole pieces:
[0086] W1=C1 / N1
[0087] Among them, C1 is the circumference of the first circle of pole pieces; N1 is the number of pole ears of the first circle of pole pieces.
[0088] like Figure 4 As shown, when i>1, according to the radius R of the i-th pole piece i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include:
[0089] Step 410: according to the radius R of the i-1th pole piece i-1 , the thickness of the single-layer diaphragm and the thickness of the pole piece, determine the radius R of the pole piece of the i-th circle i .
[0090] It should be noted that between the ith electrode and the i-1th electrode, two layers of electrodes (one positive electrode and one negative electrode) and two layers of separators are usually provided. Accordingly, the radius R of the ith electrode can be calculated by the following formula: i :
[0091]
[0092] Wherein, d is the diameter of the center hole of the battery cell to be processed; T0 is the thickness of the electrode; T1 is the thickness of the pre-rolled diaphragm.
[0093] Step 420: according to the radius R of the pole piece of the i-th circle i , calculate the circumference C of the i-th pole piece i .
[0094] The circumference of the pole piece of the i-th circle is C i The calculation method of is similar to step 320, and can be calculated using the following formula:
[0095] C i =2πR i
[0096] Step 430: According to the circumference C of the i-th pole piece i and the number of pole tabs N of the i-th pole piece i , determine the width W of the pole ear of the i-th pole piecei .
[0097] As mentioned above, the multiple tabs on each circle of pole pieces are usually evenly distributed circumferentially on the circle of pole pieces. Therefore, the tab width W of the i-th circle of pole pieces is i The following calculation formula can be used for calculation:
[0098] W i =C i / N i
[0099] Among them, C i is the circumference of the pole piece of the ith circle; N i is the number of pole lugs of the ith circle of pole pieces.
[0100] In summary, according to Figure 3 and Figure 4 The method flow shown can be based on the calculated width of each pole ear on each circle of pole pieces, so that the cutter of the laser die-cutting equipment can achieve die-cutting positioning in the length direction of the pole piece.
[0101] Next, the embodiment of the present application will focus on the two cases of i=1 and i>1, and calculate the height H of the pole ear of the pole piece of the i-th circle. i The calculation methods are explained in detail.
[0102] When i=1, according to the radius R of the pole piece of the i-th circle i , at least one of the pole piece thickness and the diaphragm thickness, calculate the pole ear height H of the i-th pole piece i , including: calculating the ear height H1 of the first circle of pole pieces according to the pre-rolled diaphragm thickness and the pole piece thickness.
[0103] The first circle of pole pieces is the innermost circle of pole pieces. The ear height H1 of the ear on the first circle of pole pieces can be calculated using the following calculation formula:
[0104] H1=T0+T1
[0105] Among them, T0 is the thickness of the pole piece; T1 is the thickness of the pre-rolled diaphragm.
[0106] Based on the above-mentioned tab height H1, the tabs on the first circle of pole pieces can cover the center hole of the battery cell to be processed after being folded inward and flattened, thereby ensuring the coverage of the tabs on the inner circle of the battery cell end face, and avoiding a series of defects caused by the lack of tab coverage on the inner circle of the battery cell end face, which is conducive to achieving full coverage of the tabs on the battery end face, as well as improving battery performance and increasing the yield rate of battery production.
[0107] When i>1, according to the radius R of the pole piece of the i-th circle i , at least one of the pole piece thickness and the diaphragm thickness, calculate the pole ear height H of the i-th pole piece i, including: according to the radius R of the pole piece of the i-th circle i , and the height H of the pole ear of the i-1th pole piece i-1 , calculate the height H of the pole lug of the i-th pole piece i .
[0108] Among them, the radius of the i-th pole piece is R i It can be determined based on the inner diameter of the battery cell, the thickness of the electrode and the thickness of the pre-rolled diaphragm. The specific calculation method has been explained above and will not be repeated here.
[0109] When calculating the height of the tab on the outer ring pole piece, by considering the radius of the pole piece and the height of the tab on the previous ring pole piece, it is ensured that the outer ring pole piece can at least overlap the tab of the previous ring pole piece after being folded inward, so that the entire end face of the battery cell can be covered with the tab, thereby avoiding the problem of welding through the diaphragm and causing short circuit and cold welding due to the lack of tabs in the inner ring, and avoiding the problem of black marks on the end face due to the lack of tabs overlapping and draining between the innermost pole piece and the outermost pole piece after the tab is formed, thereby improving the yield rate of battery production and manufacturing and improving the safety performance of the battery. Moreover, since the entire end face of the battery cell is covered by the tabs, and the tabs overlap and drain each other, it can also shorten the electron transmission path, significantly reduce the internal resistance and heat generation of the battery, and further improve the safety and thermal stability of the battery.
[0110] In one example, the height of the pole lug of the ith pole piece can be made equal to the radius R of the ith pole piece. i In this way, the pole ears on each circle of pole pieces are folded inward and flattened to cover the center hole of the battery cell to be processed, thereby ensuring that the pole ears fully cover the end face of the battery cell.
[0111] However, the above-mentioned example solution will cause the inner circle of the end face of the battery cell (near the center hole) to have obvious protrusions due to the stacking of multiple layers of tabs, which may cause welding problems such as insufficient welding strength and reduced welding area, affecting the battery's current capacity and safety, and may even cause risks such as short circuit and thermal runaway. In addition, uneven tab stacking may also affect battery performance and the structural stability of the battery. Therefore, in some embodiments of the present application, it is necessary to control the stacking of the tabs on the end face of the battery cell, and the tab height H of the i-th circle of pole pieces is 1 / 4 of the i-th circle of pole pieces. i The following calculation formula can be used for calculation:
[0112] HH i =2T0+2T1+μH i-1
[0113] Wherein, μ is the overlap coefficient, 0<μ≤1 / 2.
[0114] By adopting the above scheme, it can be ensured that the outer circle of pole ears can overlap with the inner circle of pole ears after being folded inward and flattened, and the overlapping area is small; moreover, there is only a small overlapping area or no overlapping between the outer circle of pole ears and the inner circle of pole ears in the axial direction of the battery cell to be processed, thereby avoiding excessive protrusion on the end face of the battery cell due to overlapping of the pole ears, thereby ensuring the welding strength and welding area of the pole ears on the end face of the battery cell, and avoiding the influence on the battery performance and structural stability of the battery.
[0115] In the embodiment of the present application, after testing, when 0<μ≤1 / 2, it can be ensured that the stacking of the tabs on the end face of the battery can meet the battery performance, structural stability and tab welding requirements. Among them, the overlap coefficient μ can be determined according to the width of the pole piece and the axial specification size of the battery cell to be processed. Generally speaking, in the range of 0<μ≤1 / 2, when the pole piece width differs greatly from the axial specification size of the battery cell to be processed, the overlap coefficient μ can be set to be relatively large, so that the battery cell to be processed meets the axial size specification requirements; when the pole piece width differs slightly from the axial specification size of the battery cell to be processed, the overlap coefficient μ can be set to be relatively small to avoid the tabs on the end face from being too protruding and exceeding the axial specification size requirements of the battery cell to be processed. Optionally, 1 / 4≤μ≤1 / 3.
[0116] In summary, according to the above method flow, the height of each pole ear on each circle of pole pieces can be calculated, so that the cutter of the laser die-cutting equipment can achieve die-cutting positioning in the width direction of the pole piece.
[0117] In some embodiments of the present application, according to the calculated lug width and lug height of each circle of pole pieces, die-cutting is performed on the lugs of the battery cell to be processed, including:
[0118] When die-cutting the lugs according to the calculated lug width and lug height of each circle of pole pieces, the cutter enters from the lug cutting position of the innermost circle of pole pieces and cuts out from the lug cutting position of the outermost circle of pole pieces; or, the cutter enters from the lug cutting position of the outermost circle of pole pieces and cuts out from the lug cutting position of the innermost circle of pole pieces.
[0119] like Figure 5 As shown, since the width and height of the pole lug cut by the pole lug die-cutting method provided in the embodiment of the present application vary gradually, when the cutter enters from the pole lug cutting part of the innermost circle pole piece and cuts out from the pole lug cutting part of the outermost circle pole piece, or the cutter enters from the pole lug cutting part of the outermost circle pole piece and cuts out from the pole lug cutting part of the innermost circle pole piece, the pole lug can be die-cut and formed in one step, and the waste generated is a whole piece, rather than scattered pieces, which is convenient for subsequent waste collection and processing.
[0120] Therefore, the tab die-cutting method provided in the embodiment of the present application is adopted to cut the tab into a shape whose width and height increase gradually from the inner circle to the outer circle. In this way, in the subsequent tab flattening process, the flattening mold will be more likely to fold the tab inward and flatten it, thereby increasing the coverage of the tab on the end face of the battery cell, which is conducive to achieving full coverage of the end face and improving the performance and production yield of the battery cell.
[0121] An embodiment of the present application further provides a battery having a battery cell, wherein the tabs of the battery cell are processed by the tab die-cutting method described in the above embodiment.
[0122] The battery provided in the embodiment of the present application has a high coverage rate of the tabs on the end faces of the battery cell, good battery performance, and a high yield rate in battery production, because the tabs of the battery cell are processed by the tab die-cutting method described in the above embodiment.
[0123] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the present application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only.
[0124] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.
Claims
1. A method for die-cutting a tab, characterized in that: The method comprises: According to the cell parameters of the cell to be processed, the width and height of the pole tabs of each circle of the pole piece in the cell to be processed are calculated, wherein the cell parameters include the cell diameter, the pole piece thickness, the diaphragm thickness and the total number of pole tabs, wherein the width and height of the pole tabs of each circle of the pole piece in the cell to be processed respectively increase in a gradient from the inner circle to the outer circle of the cell to be processed; The tabs of the battery cell to be processed are die-cut according to the calculated tab widths and tab heights of the pole pieces of each circle.
2. The method for die-cutting the tab according to claim 1, characterized in that: The step of calculating the width and height of the pole tabs of each pole piece in the to-be-processed battery cell according to the battery cell parameters of the to-be-processed battery cell comprises: According to the battery cell parameters, determine the radius R of the i-th circle electrode i And the number of tabs N i , 1≤i≤t, where t is the total number of windings of the electrode sheet in the battery cell to be processed, t≥2, and the electrode sheet of the tth winding is located at the outermost winding of the battery cell to be processed; According to the radius R of the i-th pole piece i And the number of tabs N i , the electrode thickness and the diaphragm thickness, calculate the width W of the pole ear of the i-th circle electrode i and the tab height H i .
3. The method for die-cutting the tab according to claim 2, characterized in that: The radius R of the pole piece of the i-th circle i And the number of tabs N i , the electrode thickness and the diaphragm thickness, calculate the width W of the pole ear of the i-th circle electrode i and the tab height H i ,include: According to the radius R of the i-th pole piece i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ; According to the radius R of the i-th pole piece i , at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i .
4. The tab die cutting method according to claim 3, characterized in that: The cell diameter includes the diameter of the central hole of the cell to be processed, and the diaphragm thickness includes the thickness of the pre-rolled diaphragm; When i=1, the radius R of the pole piece of the i-th circle i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include: Determine the radius R1 of the first circle of pole pieces according to the diameter of the central hole of the battery cell to be processed, the thickness of the pre-rolled diaphragm and the thickness of the pole piece; Calculate the circumference C1 of the first circle of pole pieces according to the radius R1 of the first circle of pole pieces; The width W1 of the pole lugs of the first circle of pole pieces is determined according to the circumference C1 of the first circle of pole pieces and the number N1 of the pole lugs of the first circle of pole pieces.
5. The tab die cutting method according to claim 4, characterized in that: The width W1 of the pole piece of the first circle is calculated using the following formula: Among them, R1 is the radius of the first circle of pole pieces; d is the diameter of the center hole of the battery cell to be processed; T0 is the thickness of the pole piece; T1 is the thickness of the pre-rolled diaphragm; C1 is the circumference of the first circle of pole pieces; N1 is the number of pole ears of the first circle of pole pieces.
6. The tab die cutting method according to any one of claims 3 to 5, characterized in that: The diaphragm thickness includes the thickness of a single-layer diaphragm; When i>1, the radius R of the pole piece of the i-th circle i And the number of tabs N i , calculate the width W of the pole ear of the i-th pole piece i ,include: According to the radius R of the i-1th pole piece i-1 , the thickness of the single-layer diaphragm and the thickness of the pole piece, determine the radius R of the pole piece of the i-th circle i ; According to the radius R of the i-th pole piece i , calculate the circumference C of the i-th pole piece i ; According to the circumference C of the i-th pole piece i and the number of pole lugs N of the pole piece of the i-th circle i , determine the width W of the pole ear of the i-th pole piece i .
7. The tab die cutting method according to claim 3, characterized in that: The diaphragm thickness includes the pre-rolled diaphragm thickness; When i=1, the radius R of the pole piece of the i-th circle i , at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i ,include: The tab height H1 of the first circle of pole pieces is calculated according to the thickness of the pre-rolled diaphragm and the thickness of the pole piece.
8. The tab die cutting method according to claim 7, characterized in that: The pole ear height H1 of the first circle pole piece is calculated using the following formula: H1=T0+T1 Among them, T0 is the thickness of the pole piece; T1 is the thickness of the pre-rolled diaphragm.
9. The method for die-cutting the tab according to claim 7 or 8, characterized in that: The diaphragm thickness includes the thickness of a single-layer diaphragm; When i>1, the radius R of the pole piece of the i-th circle i , at least one of the thickness of the pole piece and the thickness of the diaphragm, calculate the height H of the pole lug of the i-th pole piece i ,include: According to the radius R of the i-th pole piece i , and the pole ear height H of the i-1th pole piece i-1 , calculate the pole ear height H of the i-th pole piece i ; Among them, the radius R of the i-th circle pole piece i The calculation is performed using the following formula: Wherein, d is the diameter of the center hole of the battery cell to be processed; T0 is the thickness of the electrode; T1 is the thickness of the pre-rolled diaphragm.
10. The tab die cutting method according to claim 9, characterized in that: When i>1, the pole ear height H of the i-th pole piece i The calculation is performed using the following formula: H i =2T0+2T1+μH i-1 Wherein, μ is the overlap coefficient, 0<μ≤1 / 2.
11. A battery, characterized in that: The battery comprises a battery cell, and the tabs of the battery cell are processed by the tab die-cutting method according to any one of claims 1 to 10.