Gradient laser die-cutting tab forming method, tab, and battery assembly intermediate product

Abstract

The application provides a gradient laser die-cutting tab forming method, a tab and a battery assembly intermediate product, and relates to the technical field of tab forming. The gradient laser die-cuting tab forming method comprises the following steps: classifying the to-be-processed battery cell, determining whether the to-be-processed battery cell is one of a half-tab battery cell, a full-tab battery cell or a laminated battery cell; calculating the tab height corresponding to each layer of tabs in the half-tab battery cell, the full-tab battery cell or the laminated battery cell according to the thickness of the battery cell, the distance between the cover plate and the end face of the battery cell head, the distance between the tab end face and the battery cell and the number of layers of the tab; and performing laser die-cutting on each layer of tabs based on the calculated tab height of each layer of tabs, and finally completing the processing of the tab. The application can accurately calculate the height value of each layer of tabs, thereby avoiding the short circuit risk caused by the redundant tab insertion core.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tab forming, and particularly relates to a gradient laser die-cut tab forming method, a tab, and a battery assembly intermediate product. BACKGROUND

[0002] At present, the tab height of a square cell is often designed to be a uniform height, which may cause tab redundancy after cell combination. The redundant part of the tab is accumulated at the end of the cell, which may cause the tab to be inserted into the cell and further cause the risk of short circuit.

[0003] The inventor found that the prior art includes a utility model patent with the publication number CN 217656038U and the name of a gradient tab and a battery assembly intermediate product, which specifically discloses that the gradient tab is provided with a plurality of tabs arranged side by side along the thickness direction, and the height of the free end of the tab increases from front to back along the thickness direction. From the thickness direction, the free end of the tab is trapezoidal. The height increment of the free end of the tab is 0.1mm-0.3mm, and the specific value of the increment is related to the thickness of the pole piece in the winding core. The thicker the pole piece, the greater the incremental height. Conversely, the thinner the pole piece, the smaller the incremental height. The advantage of this design is that when the winding core is finally turned over to bend the tab, the tab has no redundancy and wrinkles.

[0004] The inventor found that the above technical solution gives a value of the height increment of the free end of the tab, and discloses that the value is related to the thickness of the pole piece. However, in specific implementation, it is still difficult to grasp the specific value of the incremental height, and it is impossible to accurately measure the relationship between the height of the tab and the external parameter (the thickness of the pole piece in the winding core). SUMMARY

[0005] To overcome the shortcomings of the prior art, the present application provides a gradient laser die-cut tab forming method, a tab, and a battery assembly intermediate product, which can accurately calculate the height value of each layer of tab for a half-tab cell, a full-tab cell, or a laminated cell, thereby avoiding the generation of tab redundancy and the short circuit risk caused by redundant tab insertion.

[0006] To achieve the above-mentioned purpose, one or more embodiments of the present application provide the following technical solutions:

[0007] The present application provides a gradient laser die-cut tab forming method in the first aspect.

[0008] A gradient laser die-cut tab forming method, comprising the following steps:

[0009] The types of the to-be-processed cell are divided, and it is determined whether the to-be-processed cell is one of a half-tab cell, a full-tab cell, or a laminated cell;

[0010] According to the thickness of the battery cell, the distance between the cover plate and the head end surface of the battery cell, the distance between the tab end surface and the battery cell, and the number of layers of the tab, the height of each layer of the half-tab battery cell, the full-tab battery cell or the laminated battery cell is calculated respectively.

[0011] Based on the calculated height of each layer of the tab, laser die cutting is performed on each layer of the tab, and the processing of the tab is finally completed.

[0012] As an alternative technical solution, when the battery cell to be processed is a half-tab battery cell, the specific calculation method of the height of each layer of the tab is:

[0013] The number of tabs is set to n, the nth tab of the winding is denoted as N n , and the height of N n is H n ; the thickness of the winding after hot pressing is T, the distance between the cover plate and the head end surface of the battery cell after cell combination is D, and the distance between the tab end surface and the battery cell after welding is L; then:

[0014]

[0015] As an alternative technical solution, when the battery cell to be processed is a full-tab battery cell, the specific calculation method of the height of each layer of the tab is:

[0016] After winding, the tabs from one side of the winding to the other side are denoted as N n , N n-1 ,..., N2, N1, N ’ 1, N ’ 2, N ’ 3,..., N ’ n , and the corresponding heights are denoted as H n , H n-1 ,..., H2, H1, H ’ 1H ’ 2... H ’ n , the thickness of the winding after hot pressing is T, the distance between the cover plate and the head end surface of the battery cell after cell combination is D, and the distance between the tab end surface and the battery cell after welding is L, then:

[0017]

[0018] As an alternative technical solution, when the battery cell to be processed is a laminated battery cell, the specific calculation method of the height of each layer of the tab is:

[0019] The total number of layers of the tab of the laminated battery cell is set to N, and the tab heights are H n H n-1 ... H1, H ’ 1, H’ 2…H ’ n , the thickness of the roll core after hot pressing and compaction is T, the distance between the cover plate after the core and the end surface of the battery core head is D, and the distance between the end surface of the tab after welding and the battery core is L.

[0020]

[0021] As an alternative technical solution, the tab is processed, specifically including:

[0022] Determine the cutting direction of the laser, and set the laser cutting parameters.

[0023] According to the tab root size, the tab cutting angle, the tab spacing, and the calculated tab height of each layer of tabs, the processing of the tabs is completed.

[0024] As an alternative technical solution, the tab is processed into an isosceles trapezoidal shape, and based on the tab root size, the tab cutting angle, and the calculated tab height of each layer of tabs, the tab top size is determined.

[0025] As an alternative technical solution, when laser die cutting each layer of tabs, the influence of the tolerance value also needs to be considered.

[0026] The second aspect of the application provides a tab.

[0027] A tab is prepared by using the gradient laser die cutting tab forming method based on the first aspect.

[0028] The third aspect of the application provides a battery assembly intermediate product.

[0029] A battery assembly intermediate product includes a roll core, and the roll core is provided with a tab as described in the second aspect.

[0030] As an alternative technical solution, the roll core is a lithium ion battery roll core, and the roll core is placed in a square aluminum shell.

[0031] The above one or more technical solutions have the following beneficial effects:

[0032] The application provides a gradient laser die-cutting tab forming method, a tab and a battery assembly intermediate product, based on the thickness of the battery cell, the distance between the cover plate and the head end surface of the battery cell, the distance between the tab end surface and the battery cell and the number of layers of the tab, the height of each layer of the tab corresponding to the half-tab battery cell, the full-tab battery cell or the laminated battery cell is accurately calculated, and then the laser die-cutting is performed on each layer of the tab based on the calculated height of each layer of the tab, so that the processing of the tab is completed. Compared with the prior art, the height of each layer of the tab can be accurately calculated, the accurate height value is obtained, the height of each layer of the tab is accurately controlled, and the short circuit risk caused by the redundant tab insertion is fundamentally avoided.

[0033] In the application, the influences of the thickness of the battery cell, the distance between the cover plate and the head end surface of the battery cell, the distance between the tab end surface and the battery cell and the number of layers of the tab are comprehensively considered in the process of calculating the height of each layer of the tab, the correlation between the tab height and the four factors is found out, and compared with the prior art which only considers the correlation between the tab height and the thickness of the winding core tab, the tab height value obtained by the application is more accurate.

[0034] In the application, the tab is processed into an isosceles trapezoidal shape, the tab top size is determined based on the tab root size, the tab cutting angle and the calculated height of each layer of the tab, and the laser die-cutting processing is facilitated.

[0035] The gradient cutting tab method provided by the application can also avoid the problem that the laser cutting tab edge cannot be detached. Because the cutting residue size needs to be greater than or equal to 4mm when the tab is cut by laser, and the cutting residue size that is too short will cause the cut part to be difficult to fall off. The gradient cutting tab method can increase the falling size of the rear tab, and can solve the problem of not falling off during tab cutting to a certain extent.

[0036] The advantages of the additional aspects of the application will be partially given in the following description, partially will become obvious from the following description, or will be known by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0037] The drawings accompanying the specification of the application form part of the application and serve to provide further understanding of the application. The schematic embodiments of the application and the description thereof serve to explain the application and do not constitute an improper limitation of the application.

[0038] Figure 1 A schematic diagram for the short circuit risk caused by the tab insertion in the prior art.

[0039] Figure 2 A side view of the half-tab battery cell in the first embodiment.

[0040] Figure 3 A parameter schematic diagram in the tab forming method of the half-tab battery cell in the first embodiment.

[0041] Figure 4 Figure 1 is a side view of a full tab cell according to the first embodiment.

[0042] Figure 5 Figure 2 is a schematic diagram of parameters in the tab forming method of the full tab cell according to the first embodiment.

[0043] Figure 6 Figure 3 is a side view of a tab cell according to the first embodiment.

[0044] Figure 7 Figure 4 is a diagram of the connection position of the positive electrode tab and the tab of the tab cell.

[0045] Figure 8 Figure 5 is a diagram of the connection position of the negative electrode tab and the tab of the tab cell.

[0046] Figure 9 Figure 6 is a schematic diagram of die cutting each layer of tabs.

[0047] In the drawings, the components represented by the reference numbers are listed as follows:

[0048] 1 cell, 2 redundant tab, 3 welding mark, 4 cover plate, 5 tab, 6 winding core, 7 each layer of tabs, 8 tab cell, 9 tab, 10 cut-out part, 11 falling vertical part. DETAILED DESCRIPTION

[0049] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0050] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit the exemplary embodiments according to the present application.

[0051] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0052] Embodiment One

[0053] The tab is a component of a lithium ion polymer battery product. The battery is divided into positive and negative electrodes, and the tab is a metal conductor that leads out the positive and negative electrodes from the cell. In simple terms, the ears of the positive and negative electrodes of the battery are the contact points during charging and discharging. This contact point is not the copper sheet on the outside of the battery that we see, but a kind of connection inside the battery. The tab, as a link for current transmission during charging and discharging, its heat and electrical conductivity performance will also affect the performance of the battery.

[0054] The battery structure includes positive and negative electrodes, electrolyte, separator and shell. When the positive electrode, separator and negative electrode inside the battery are processed, a conductive medium needs to be welded to connect the cell and the shell. The tab is a metal conductive medium that leads the positive and negative electrodes out of the cell 1.

[0055] The half-tab in the present embodiment refers to one tab per circle (two layers of tabs), and the full-tab refers to one tab per layer of tabs.

[0056] As shown in Figure 1 , since the current square cell 1 tab height is uniform, after cell combination, the tab may have redundancy, and the redundant tab 2 is stacked at the end of the cell 1, which may cause the tab to be inserted into the cell 1, resulting in a short circuit risk. The gradient laser die cutting tab forming method provided in the present embodiment aims to solve the problem of internal redundancy of the tab and avoid the safety risk of short circuit from the root cause.

[0057] Based on the content disclosed in the foregoing background art, the prior art discloses a technical solution in which the height of the free end of the tab increases by 0.1mm-0.3mm, and the specific value of the increment is related to the thickness of the tab 9 in the winding core 6. The thicker the tab 9, the greater the incremental height; on the contrary, the thinner the tab 9, the smaller the incremental height. The advantage of this design is that when the winding core 6 is finally turned over to bend the tab, the tab has no redundancy and wrinkles. However, in specific implementation, it is still difficult to determine the specific value of the incremental height, and it is impossible to accurately measure the relationship between the height of the tab and the external parameters (the thickness of the tab 9 in the winding core 6).

[0058] The present embodiment aims to accurately calculate and control the height of each layer of tabs, and thus to avoid the short circuit risk caused by the insertion of redundant tabs 2. The present embodiment discloses a gradient laser die cutting tab forming method, which can specifically include the following steps:

[0059] Classify the types of the cell to be processed, and determine whether the cell to be processed is one of a half-tab cell, a full-tab cell or a laminated cell;

[0060] According to the thickness of the cell, the distance between the cover plate and the end surface of the cell head, the distance between the tab end surface and the cell, and the number of layers of the tab, the height of each layer of tabs 7 corresponding to the half-tab cell, the full-tab cell or the laminated cell is calculated respectively;

[0061] Based on the calculated height of each layer of tabs 7, laser die cutting is performed on each layer of tabs 7 respectively, and finally the processing of the tabs is completed.

[0062] In order to accurately calculate the height of each layer of tabs 7, the present embodiment provides three specific calculation methods for the height of the tab, which specifically include:

[0063] (1) AsFigure 2 and Figure 3 As shown, when the cell to be processed 1 is a half-tab cell, the specific calculation method for the tab height corresponding to each tab layer 7 is as follows:

[0064] Let n be the number of laser-cut tabs in a half-tab battery cell. The first tab (the first one on the inner ring) is denoted as N1, and its height is H1. The second tab is denoted as N2, and its height is H2, and so on, with the nth tab denoted as N... n N n The height is H n ,like Figure 3 As shown.

[0065] like Figure 2 As shown, the thickness of the core 6 after hot pressing is T; the tab 5 is connected to one side of the core 6 using a half-tab method. Figure 1 As shown, the distance between the back cover plate 4 and the head end face of the battery cell 1 is D, and the distance between the end face of the electrode tab solder mark 3 and the battery cell 1 after welding is L. The calculation method for the electrode tab height die-cutting dimension during laser die-cutting is as follows:

[0066]

[0067] In other words, for half-pole cells:

[0068]

[0069] Figure 3 In the diagram, the direction of the arrow indicates the laser cutting direction. Set the laser cutting parameters, where the root dimension of the electrode is W, the electrode cutting angle is φ, and the electrode spacing is M1, M2, M3…M n The heights of the electrodes are H1, H2, H3…H n Among them, H1, H2, H3…H n The height value of each layer of tab 7 is calculated according to the above method.

[0070] (2) Figure 4 and Figure 5 As shown, when the cell to be processed is a full-tab cell, the specific calculation method for the tab height corresponding to each tab layer 7 is as follows:

[0071] like Figure 4 As shown, the thickness of the core 6 after hot pressing is T; the tab 5 is connected to one side of the core 6 using a full tab method.

[0072] like Figure 5 As shown, for a full-tab cell, counting by half a turn, the first tab (the first one on the inner turn) is denoted as N. 1， The numbers are N2, N3, ... N, going outwards in sequence. n The heights are H1 H2…Hn ;

[0073] With Figure 4 the dashed line as the center of symmetry, the tab is from the inner ring with this dashed line as the symmetry axis, from the symmetric position, the height of each layer of tab 7 is N ’ 1, N ’ 2, N ’ 3, N ’ n , the height is H ’ 1H ’ 2…H ’ n .

[0074] For easy understanding, the positional relationship of N n , N n-1 , N2, N1, N ’ 1, N ’ 2, N ’ 3, N ’ n is shown in Figure 4 , as shown in Figure 4 , set after winding, the tab from one side of the winding core to the other side is respectively recorded as N n , N n-1 , N2, N1, N ’ 1, N ’ 2, N ’ 3, N ’ n , the corresponding height is respectively recorded as H n , H n-1 , H2, H1, H ’ 1H ’ 2…H ’ n .

[0075] Then, the tab height die cutting size is as follows:

[0076]

[0077] That is, for the symmetrical area on one side of the full tab cell, the first tab wound (the first inner ring) is recorded as N 1， , and the outer ring is N2, N3, N n , and the height is H1 H2…H n :

[0078]

[0079] And:

[0080]

[0081]

[0082] That is, for the symmetrical region on the other side of the full tab cell, the height of each layer of tab is N ’ 1, N ’ 2, N ’ 3, … N ’ n , the height of each layer of tab is H ’ 1H ’ 2…H ’ n Then:

[0083]

[0084] (3) As shown in Figure 6 , Figure 7 and Figure 8 , when the to-be-processed cell is a laminated cell 8, the thickness of the laminated cell 8 after hot pressing and compaction is T; the tab 5 is connected to one side of the laminated cell 8. The specific calculation method of the tab height corresponding to each layer of tab 7 is as follows:

[0085] Set the total number of tabs of the laminated cell 8 as n, and the tab height from bottom to top is H n H n-1 …H1, H ’ 1, H ’ 2…H ’ n When cutting the tab 9 and the tab, the size is as follows:

[0086]

[0087] That is:

[0088]

[0089] And:

[0090]

[0091] That is:

[0092]

[0093] After the height of each layer of tab 7 in the half-tab cell, the full-tab cell or the laminated cell is accurately calculated according to the above three methods, the tab needs to be processed next, which specifically includes:

[0094] Determine the cutting direction of the laser, and set the laser cutting parameters;

[0095] According to the lug root size, the lug cutting angle, the lug spacing, and the calculated lug height of each layer of lug 7, the processing of the lug is completed. Among them, the lug root size, the lug cutting angle and the lug spacing are preset parameter values.

[0096] Further, the lug is processed into an isosceles trapezoidal shape, and the lug top size is determined based on the lug root size, the lug cutting angle, and the calculated lug height of each layer of lug 7.

[0097] When laser die cutting is performed on each layer of lug 7, the influence of the tolerance value also needs to be considered. In this embodiment, the tolerance value is set to 5%.

[0098] The above method of this embodiment is a new type of die-cut lug method, which aims to solve the short circuit risk of the lug plug caused by the same lug height. The lug cutting method can well improve the lug redundancy problem, and further perfectly solve the short circuit risk caused by the insertion of the lug redundancy into the roll core 6.

[0099] In addition, as Figure 9 indicated, the gradient cutting lug method provided in this embodiment can also avoid the problem that the laser-cut lug edge cannot be detached. Because when laser cutting the lug, the cutting excess size needs to be ≥4mm, and too short excess size will cause the cut part to be difficult to fall off; and by using the gradient cutting lug method of this embodiment, the falling size of the rear lug can be increased, which can solve the problem of not falling off when cutting the lug to a certain extent.

[0100] That is, in Figure 9 , the black area is the area of each layer of lug 7, and the white area in the dashed box is the cut part 10, wherein the gradient die-cut lug method can increase Figure 9 the height of the falling vertical part 11 in , which can avoid the problem that the laser-cut lug edge cannot be detached to a certain extent.

[0101] Embodiment Two

[0102] The embodiment discloses a lug.

[0103] A lug is prepared by using the gradient laser die-cut lug forming method described in embodiment one.

[0104] Embodiment Three

[0105] The embodiment discloses a battery assembly intermediate product.

[0106] A battery assembly intermediate product includes a roll core 6, wherein the roll core 6 is provided with the lug described in embodiment two; the roll core 6 is a lithium ion battery roll core, and the roll core 6 is placed in a square aluminum shell.

[0107] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A gradient laser die-cutting method for forming tabs, characterized in that, Includes the following steps: Classify the cells to be processed to determine whether they are one of the following: half-tab cells, full-tab cells, or laminated cells. Based on the cell thickness, the distance between the cover plate and the cell head end face, the distance between the tab end face and the cell, and the number of tab layers, calculate the tab height corresponding to each layer of tabs in half-tab cells, full-tab cells, or laminated cells respectively. Based on the calculated tab height of each layer, each tab is laser-divided to complete the tab processing.

2. The gradient laser die-cutting tab forming method as described in claim 1, characterized in that, When the battery cell to be processed is a half-tab battery cell, the specific calculation method for the tab height corresponding to each tab layer is as follows: Let the number of tabs be n, and let N be the nth tab wound on the coil. n N n The height is H n The thickness of the core after hot pressing is T; the distance between the cover plate and the end face of the cell head after core assembly is D; the distance between the end face of the electrode tab and the cell after welding is L; then:

3. The gradient laser die-cutting tab forming method as described in claim 1, characterized in that, When the battery cell to be processed is a full-tab battery cell, the specific calculation method for the tab height corresponding to each tab layer is as follows: After the winding is completed, the tabs from one side of the core to the other are denoted as N. n N n-1 ...N2, N1, N ’ 1. N ’ 2. N ’ 3、···N ’ n The corresponding heights are denoted as H. n H n-1 H2, H1, H ’ 1H ’ 2…H ’ n The thickness of the core after hot pressing is T, the distance between the cover plate and the end face of the cell head after core assembly is D, and the distance between the end face of the electrode tab and the cell after welding is L. Then:

4. The gradient laser die-cutting tab forming method as described in claim 1, characterized in that, When the battery cell to be processed is a laminated battery cell, the specific calculation method for the tab height corresponding to each layer of tabs is as follows: Let N be the total number of layers of tabs in the laminated battery cell, and let H be the height of the tabs from bottom to top. n H n-1 …H1、H ’ 1. H ’ 2…H ’ n The thickness of the core after hot pressing is T, the distance between the cover plate and the end face of the cell head after core assembly is D, and the distance between the end face of the electrode tab and the cell after welding is L. Then:

5. The gradient laser die-cutting tab forming method as described in claim 1, characterized in that, The processing of the electrode tabs specifically includes: Determine the laser cutting direction and set the laser cutting parameters; The electrode processing is completed based on the electrode root size, electrode cutting angle, electrode spacing, and the calculated electrode height of each layer of electrodes.

6. The gradient laser die-cutting tab forming method as described in claim 5, characterized in that, The tabs are processed into isosceles trapezoidal shapes. Based on the dimensions of the tab root, the tab cutting angle, and the calculated tab height of each layer, the dimensions of the top of the tab are determined.

7. The gradient laser die-cutting tab forming method as described in claim 1, characterized in that, When performing laser die-cutting on each layer of tabs, the influence of tolerance values ​​also needs to be considered.

8. A type of electrode, characterized in that, It is prepared using the gradient laser die-cutting tab forming method according to any one of claims 1-7.

9. A battery assembly intermediate, characterized in that, It includes a winding core, on which the electrode tabs as described in claim 8 are provided.

10. The battery assembly intermediate as described in claim 9, characterized in that, The core is a lithium-ion battery core, and the core is placed inside a square aluminum shell.

Images