Extremely simple cover plate and battery cell

Abstract

An extremely simple cover plate and a battery cell, relating to the technical field of batteries. The extremely simple cover plate comprises: a pole assembly (10); and a top cover piece (20), welded and connected to the pole assembly (10), a welding track being formed between the top cover piece (20) and the pole assembly (10), the top cover piece (20) comprising a contraction region (21) and a non-contraction region (22), and the welding track being located in the contraction region (21). Before welding, the dimension of the contraction region (21) in a first direction (D1) is the sum of a preset dimension of the top cover piece (20) in the first direction (D1) and a first deformation allowance, and the dimension of the contraction region (21) in a second direction (D2) is the sum of a preset dimension of the top cover piece (20) in the second direction (D2) and a second deformation allowance. According to the extremely simple cover plate, it can be ensured that after the pole assembly (10) and the top cover piece (20) are welded and connected, the actual dimensions of the top cover piece (20) in the first direction (D1) and the second direction (D2) are respectively the same as the preset dimensions, so as to avoid an excessively large gap between the contraction region (21) of the extremely simple cover plate and the periphery of a casing of a battery cell, so that the risk of poor welding is reduced, and the quality of the battery cell is guaranteed.

Description

Minimalist cover and battery cell

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410109959.2, filed with the China Patent Office on January 26, 2024, entitled “Minimal Cover and Battery Cell,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a minimalist cover and battery cell. Background Art

[0004] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields. Therefore, the requirements for the performance and safety of lithium-ion batteries are increasing.

[0005] The lithium battery cover is a key component in lithium-ion batteries. Its function is to weld with the shell to form a sealed cavity, lead out the positive and negative electrodes of the electrode group, and serve as an assembly carrier. The battery cover consists of a plain aluminum sheet and a pole welded to the plain aluminum sheet. Because the center of the pole is close to the edge of the cover, the length and width of the plain aluminum sheet shrink after the pole and the plain aluminum sheet are welded and fixed due to the influence of welding heat. As a result, after the cover and the shell are matched, the local gap around the shrinkage area is too large, which poses a risk of poor welding, which can easily cause battery leakage and affect the battery yield.

[0006] Application Contents

[0007] In view of this, the purpose of this application includes providing a minimalist cover plate and battery cell, so as to solve to a certain extent the technical problem that the poles and bare aluminum sheets welded together on the cover plate in the prior art are affected by the welding heat, and the length and width of the bare aluminum sheet are locally shrunk after the poles and the bare aluminum sheet are welded and fixed, resulting in excessive local gaps around the shrinkage area after the cover plate and the shell are assembled, and there is a risk of poor welding.

[0008] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0009] This application provides a minimalist cover, including:

[0010] Pole assembly;

[0011] A top cover sheet is welded to the pole assembly, a welding track is formed between the top cover sheet and the pole assembly, the top cover sheet includes a shrinkage area and a non-shrinkage area, and the welding track is located in the shrinkage area;

[0012] Before welding, the size of the shrinkage zone in the first direction is the sum of the preset size of the top cover sheet in the first direction and the first deformation allowance, the first deformation allowance is 1 / [(12~18)t1], t1 is the distance from the pole assembly to the edge of the top cover sheet in the first direction; the size of the shrinkage zone in the second direction is the sum of the preset size of the top cover sheet in the second direction and the second deformation allowance, the second deformation allowance is 1 / [(12~18)t2], t2 is the distance from the pole assembly to the edge of the top cover sheet in the second direction.

[0013] In the above technical solution, further, the top cover sheet is formed into a rectangular structure.

[0014] In any of the above technical solutions, further, the first direction is the length direction of the rectangular structure, and the second direction is the width direction of the rectangular structure.

[0015] In any of the above technical solutions, further, the length dimension of the top cover piece is (40+B)±(0.03-0.08) mm, wherein B≥0.

[0016] In any of the above technical solutions, further, the width dimension of the top cover sheet is (11+A)±(0.03-0.08) mm, wherein A≥0.

[0017] In any of the above technical solutions, further, the second deformation margin is not less than the first deformation margin.

[0018] In any of the above technical solutions, further, the axis of the welding track is located in the middle of the contraction zone, and the axis extends along the third direction.

[0019] In any of the above technical solutions, further, the shrinkage area and the non-shrinkage area are spaced apart; and the top cover sheet further comprises:

[0020] A transition zone is arranged between the contraction zone and the non-contraction zone.

[0021] In any of the above technical solutions, further, different parts of the shrinkage zone have different sizes, and the size of the shrinkage zone increases as the welding track approaches the edge of the top cover sheet.

[0022] In any of the above technical solutions, further, t1 is 2mm to 15mm

[0023] In any of the above technical solutions, further, t2 is 2 mm to 25 mm.

[0024] In any of the above technical solutions, further, at least one pole assembly is provided; when multiple pole assemblies are provided, the multiple pole assemblies are arranged at intervals along the first direction, the welding tracks are arranged in a one-to-one correspondence with the pole assemblies, and the non-shrinkage area is provided between adjacent welding tracks.

[0025] In any of the above technical solutions, further, along the first direction, the size of the non-contracted area is not smaller than the size of the contracted area adjacent to it.

[0026] In any of the above technical solutions, further, the pole assembly includes:

[0027] pole;

[0028] A support member is formed into an annular structure and is sleeved on the side of the pole body, and the support member is welded to the top cover sheet;

[0029] An insulating member is arranged between the supporting member and the top cover sheet.

[0030] The present application also provides a battery cell formed by assembling a minimalist cover plate including any of the above technical solutions.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] The minimalist cover provided in this application includes:

[0033] Pole assembly;

[0034] A top cover sheet is welded to the pole assembly, a welding track is formed between the top cover sheet and the pole assembly, the top cover sheet includes a shrinkage area and a non-shrinkage area, and the welding track is located in the shrinkage area;

[0035] Before welding, the size of the shrinkage zone in the first direction is the sum of the preset size of the top cover sheet in the first direction and the first deformation allowance, the first deformation allowance is 1 / [(12~18)t1], t1 is the distance from the pole assembly to the edge of the top cover sheet in the first direction; the size of the shrinkage zone in the second direction is the sum of the preset size of the top cover sheet in the second direction and the second deformation allowance, the second deformation allowance is 1 / [(12~18)t2], t2 is the distance from the pole assembly to the edge of the top cover sheet in the second direction.

[0036] The minimalist cover provided by the present application divides the top cover into a shrinkage area and a non-shrinkage area and leaves a deformation margin in the shrinkage area to ensure that after the pole assembly is welded to the top cover, the actual dimensions of the top cover in the first direction and the second direction are the same as the preset dimensions. In this way, it is ensured that the minimalist cover and the battery cell shell can be assembled tightly, and the consistency and yield of the minimalist cover size are guaranteed, thereby reducing the risk of poor welding, ensuring welding quality, and avoiding the problem of battery cell leakage, effectively improving the battery yield, and effectively improving production efficiency and saving costs during mass production of battery cells.

[0037] The battery cell provided in the present application includes the above-mentioned minimalist cover plate, and therefore has all the beneficial effects of the above-mentioned minimalist cover plate, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] FIG1 is an exploded view of the structure of a minimalist cover plate provided in an embodiment of the present application;

[0040] FIG2 is a schematic structural diagram of a welding track in a minimalist cover plate provided in an embodiment of the present application;

[0041] FIG3 is a schematic diagram of the distribution structure of the contraction area, non-contraction area and transition area of ​​the top cover sheet of the minimalist cover provided by an embodiment of the present application in the first direction;

[0042] FIG4 is a schematic diagram of the distribution structure of the contraction area, the non-contraction area, and the transition area of ​​the top cover sheet in the second direction of the minimalist cover provided by an embodiment of the present application;

[0043] FIG5 is a schematic diagram showing the positions of t1 and t2 on the top cover sheet of the minimalist cover plate provided in an embodiment of the present application;

[0044] FIG6 is an exploded view of the structure of the pole assembly in the minimalist cover provided in an embodiment of the present application;

[0045] FIG7 is a cross-sectional view of the structure of a minimalist cover plate provided in an embodiment of the present application;

[0046] FIG8 is a schematic diagram of the assembly structure of the pole and the support member in the minimalist cover provided in an embodiment of the present application;

[0047] FIG9 is a schematic structural diagram of a first top cover sheet in another structure of a minimalist cover plate provided in an embodiment of the present application;

[0048] FIG10 is a schematic structural diagram of the second top cover sheet in another structure of the minimalist cover plate provided in an embodiment of the present application.

[0049] Figure markings: 10-pole assembly; 11-pole; 101-positive pole; 102-negative pole; 111-positioning groove; 12-support member; 121-positioning part; 122-slot; 13-insulating member; 131-block; 20-top cover piece; 201-first top cover piece; 202-second top cover piece; 21-contraction area; 22-non-contraction area; 23-transition area; 30-welding track; 40-liquid injection hole; 50-pressure relief member; 60-lower plastic; 70-sealing member; D1-first direction; D2-second direction; D3-third direction. DETAILED DESCRIPTION

[0050] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0051] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present application.

[0052] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0053] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0055] The minimalist cover and battery cell according to the embodiments of the present application are described below with reference to FIG. 1 to FIG. 10 .

[0056] The pole assembly 10 includes an assembled pole 11, a support 12, and an insulating member 13. The pole 11 is connected to the lug extending from the cell pole group. The support 12 is formed into an annular structure and is sleeved on the circumferential side of the body of the pole 11. The support 12 is welded to the top cover 20 to ensure that the pole 11 is fixedly connected to the top cover 20. The insulating member 13 is arranged between the support 12 and the top cover 20. The insulating member 13 is also formed into an annular structure to ensure full coverage. In this embodiment, the insulating member 13 is formed by injection molding.

[0057] Specifically, a recessed positioning groove 111 is provided on the circumference of the pole 11, and a protruding positioning portion 121 is provided on the inner wall of the support member 12 to extend into the positioning groove 111. This ensures that after the pole 11 and the support member 12 are assembled, the cooperation between the positioning portion 121 and the positioning groove 111 can prevent the pole 11 and the support member 12 from rotating. The positioning portion 121 and the positioning groove 111 are provided in a one-to-one correspondence, and the positioning portion 121 and the positioning groove 111 form a group of positioning structures. The positioning structures can be provided in one or more groups. When the positioning structures are provided in multiple groups, the positioning grooves 111 are provided at equal intervals around the circumference of the pole 11, and the positioning portions 121 are provided at equal intervals around the inner wall of the support member 12. This ensures uniform force and reliable anti-rotation.

[0058] More specifically, a recessed slot 122 is formed on the outer wall of the support member 12, and a protruding block 131 is formed on the inner wall of the insulating member 13. When the support member 12 and the insulating member 13 are assembled, the block 131 can extend into the slot 122 to prevent the insulating member 13 and the support member 12 from rotating relative to each other. The blocks 131 and the slots 122 are arranged in a one-to-one correspondence, forming a set of locking structures. The locking structures can be provided as one or more sets. When multiple sets of locking structures are provided, the blocks 131 are arranged at equal intervals around the circumference of the insulating member 13, and the slots 122 are arranged at equal intervals around the outer wall of the support member 12, thereby ensuring reliable anti-rotation.

[0059] Preferably, the slot 122 can be arranged corresponding to the positioning portion 121, so that when the slot 122 is stamped on the outer wall of the support member 12, the inner wall of the support member 12 can simultaneously form a protruding positioning portion 121, thereby saving manufacturing cost and time.

[0060] The top cover sheet 20 is welded to the pole assembly 10. Specifically, an opening is formed in the top cover sheet 20, the pole assembly 10 is assembled into the opening, and the support member 12 is welded to the top cover sheet 20. In this embodiment, as shown in FIG2 , a welding track 30 is formed between the top cover sheet 20 and the pole assembly 10. The welding track 30 is adapted to the shape of the pole assembly 10. For example, when the pole 11 is circular, the welding track 30 is also formed into a circular and closed linear structure. However, the shape of the welding track 30 is not limited to this, and can also be formed into a square, runway, or other shape, as long as it can ensure a firm and reliable connection between the pole assembly 10 and the top cover sheet 20.

[0061] Due to the influence of welding heat during the welding process of the pole assembly 10 and the top cover sheet 20, the area on the top cover sheet 20 shrinks after the pole assembly 10 and the top cover sheet 20 are welded, and the size of the area changes, thereby affecting the consistency and yield of the minimalist cover plate size.

[0062] Optionally, the positive electrode column and the negative electrode column are arranged on the same top cover sheet 20. Optionally, two top cover sheets are provided, namely a first top cover sheet 201 and a second top cover sheet 202, wherein the first top cover sheet 201 is installed on the positive side of the battery cell, and the second top cover sheet 202 is installed on the negative side of the battery cell, the positive electrode column 101 is welded to the first top cover sheet 201, and the negative electrode column 102 is installed on the second top cover sheet 202. In addition, the liquid injection hole 40 described below is provided on the second top cover sheet 202, and the pressure relief member 50 described below is provided on the first top cover sheet 201.

[0063] In order to solve the above problems, preferably, the top cover sheet 20 includes a shrinkage area 21 and a non-shrinkage area 22, and the welding track 30 is located in the shrinkage area 21; before welding, the dimension X of the shrinkage area 21 in the first direction D1 is the sum of the preset dimension X0 of the top cover sheet 20 in the first direction D1 and the first deformation allowance L1, the first deformation allowance L1 is 1 / [(12~18)t1], t1 is the distance from the pole assembly 10 to the edge of the top cover sheet 20 in the first direction D1, that is, X=X0+L1=X0+1 / [(12~18)t1], the dimension Y of the shrinkage area 21 in the second direction D2 is the sum of the preset dimension Y0 of the top cover sheet 20 in the second direction D2 and the second deformation allowance L2, the second deformation allowance L2 is 1 / [(12~18)t1], t1 is the distance from the pole assembly 10 to the edge of the top cover sheet 20 in the first direction D1, that is, X=X0+L1=X0+1 / [(12~18)t1], the dimension Y of the shrinkage area 21 in the second direction D2 is the sum of the preset dimension Y0 of the top cover sheet 20 in the second direction D2 and the second deformation allowance L2, The margin L2 is 1 / [(12~18)t2], where t2 is the distance from the pole assembly 10 to the edge of the top cover sheet 20 in the second direction D2, that is, Y=Y0+L2=Y0+1 / [(12~18)t2]; the units of L1, L2, X0, Y0, X and Y are all mm; in this way, the dimensions of the shrinkage area 21 and the non-shrinkage area 22 on the top cover sheet 20 after welding in the first direction D1 and the second direction D2 are consistent and meet the preset size requirements, thereby improving the yield of the minimalist cover plate, and then ensuring the reliable assembly of the minimalist cover plate and the battery cell shell, avoiding the local gap around the shrinkage area 21 of the top cover plate 20 and the battery cell shell being too large, thereby reducing the risk of poor welding and ensuring the quality of the battery cell.

[0064] Preferably, t1 is 2 mm to 15 mm; and / or t2 is 2 mm to 25 mm. When t1 and / or t2 are within the above-defined ranges, the parameters calculated using the limiting conditions of X = X0 + 1 / [(12-18)t1] mm and / or Y = Y0 + 1 / [(12-18)t2] mm can ensure that the shape accuracy and dimensional accuracy of the welded minimalist cover meet the design requirements.

[0065] It should be noted that the contraction area 21 and non-contraction area 22 on the top cover sheet 20 are not divided by area, but rather by whether there is a dimensional change compared to a preset dimension when measured only along the first direction D1 or along the second direction D2. Specifically, the dimension X of the contraction area 21 in the first direction D1 is shown in Figure 4, where the contraction area 21 and non-contraction area 22 are spaced apart along the second direction D2. The dimension Y of the contraction area 21 in the second direction D2 is shown in Figure 3, where the contraction area 21 and non-contraction area 22 are spaced apart along the first direction D1.

[0066] It should be further explained that the preset size X0 and the preset size Y0 are basic sizes (ie, sizes given in the design) that meet the assembly requirements of the top cover piece 20 and the battery cell housing.

[0067] Preferably, as shown in Figures 1 to 5, the top cover sheet 20 is formed into a rectangular structure, with the first direction D1 being the length direction of the rectangular structure and the second direction D2 being the width direction of the rectangular structure; preferably, the length dimension of the top cover sheet 20 is (40+B)±(0.03-0.08) mm, where B≥0; the width dimension of the top cover sheet 20 is (11+A)±(0.03-0.08) mm, where A≥0, thereby limiting the size range of the top cover sheet 20, thereby improving the reliability of the parameter definition of the first deformation allowance L1 and the second deformation allowance L2, and further ensuring that the dimensions of the shrinkage area 21 and the non-shrinkage area 22 on the welded top cover sheet 20 in the first direction D1 and the second direction D2 are consistent and meet the preset size requirements. It should be noted that the length dimension of the top cover sheet 20 is the above-mentioned preset size X0; the width dimension of the top cover sheet 20 is the above-mentioned preset size Y0.

[0068] Since the dimension in the width direction is smaller than that in the length direction, and the relatively smaller part is easy to deform, preferably, the second deformation allowance L2 is not less than the first deformation allowance L1, thereby ensuring that the dimensions of the top cover sheet 20 in the length direction and the width direction meet the preset size requirements, so that there will be no excessive gap between the four sides of the minimalist cover and the battery cell shell.

[0069] Preferably, as shown in Figure 3 or Figure 4, the axis of the welding track 30 is located in the middle position of the contraction area 21, thereby improving the uniformity of the deformation of the circumferential top cover sheet 20 located at the welding track 30 during the welding process, thereby effectively controlling the shape and size of the top cover sheet 20 after welding to be consistent with the design requirements.

[0070] It should be noted that the axis of the welding track 30 extends along the third direction D3, that is, when the welding track 30 is circular, the axis of the welding track 30 passes through the center of the circle.

[0071] It should be further explained that the first direction D1 , the second direction D2 , and the third direction D3 are perpendicular to each other.

[0072] Since the top cover sheet 20 and the pole assembly 10 are affected by the welding process during the welding connection, when there are slight changes in parameters such as welding speed, welding current, welding angle and / or welding time, the limited area range of the shrinkage zone 21 and the non-shrinkage zone 22 of different top cover sheets 20 in the same batch may change accordingly, for this reason, the shrinkage zone 21 and the non-shrinkage zone 22 are arranged at intervals; the top cover sheet 20 also includes a transition zone 23 arranged between the shrinkage zone 21 and the non-shrinkage zone 22, and the transition zone 23 is respectively connected to the shrinkage zone 21 and the non-shrinkage zone 22, and the size of the transition zone 23 close to the shrinkage zone 21 is the maximum limit size of the preset size, thereby avoiding the influence of the welding process on the size of the non-shrinkage zone 22.

[0073] Preferably, the dimensions of the contraction zone 21 vary across different locations. Specifically, the parameters of the contraction zone 21 in the first direction D1 or the second direction D2 are not constant. Instead, the dimensions of the contraction zone 21 increase as the weld track 30 approaches the edge of the top cover sheet 20 (i.e., the closer the weld track 30 is to the edge of the top cover sheet 20, the larger the corresponding dimensions of the contraction zone 21). It should be noted that when the dimensions of the contraction zone 21 vary across different locations, the X or Y parameters can be determined by weighing the different locations multiple times and taking the average of the values.

[0074] Preferably, in the second direction D2, the pole assembly 10 is arranged in the middle position of the top cover sheet 20, so that the distances from both ends of the top cover sheet 20 to the pole assembly 10 in the second direction D2 are equal, to ensure uniform deformation of the top cover sheet 20 in the second direction D2.

[0075] Preferably, the welding trajectory 30 includes straight segments and / or curved segments; the end shape of the contraction zone 21 in the first direction D1 or the second direction D2 is the same as the shape of the portion of the welding trajectory 30 opposite thereto, that is, the shape of the edge of the contraction zone 21 located at the top cover sheet 20 is adapted to the shape of the corresponding welding trajectory 30, so that the distance between any end point of the contraction zone 21 in the first direction D1 or the second direction D2 and the welding trajectory 30 is the same, that is, for example, when the welding trajectory 30 is formed into a circle, the edge of the contraction zone 21 is in an arc shape, thereby ensuring uniform welding deformation.

[0076] At least one pole assembly 10 is provided in the minimalist cover plate; when multiple pole assemblies 10 are provided, the multiple pole assemblies 10 are arranged at intervals along the first direction D1, the welding tracks 30 are arranged in a one-to-one correspondence with the pole assemblies 10, and a non-contraction area 22 is provided between adjacent welding tracks 30, so as to avoid mutual influence between two adjacent pole assemblies 10 when welded to the top cover sheet 20, resulting in unreliable assembly of the pole assembly 10, or causing the limited range of L1=1 / [(12~18)t1] and / or L2=1 / [(12~18)t2] to be inaccurate.

[0077] In order to improve the reliability of two adjacent pole assemblies 10 not affecting each other when welded to the top cover plate 20, preferably, along the first direction D1, the size of the non-shrinkage area 22 is not less than the size of the shrinkage area 21 adjacent to it, so as to ensure that there is a safe distance between the adjacent shrinkage areas 21 that are not affected by welding with each other, thereby ensuring the reliable assembly of the minimalist cover and improving the yield of the minimalist cover.

[0078] Preferably, as shown in Figures 1, 9 and 10, the minimalist cover also includes a liquid injection hole 40, a pressure relief piece 50, a lower plastic 60 and a sealing piece 70. The liquid injection hole 40 is formed as a through-hole structure and is opened on the top cover piece 20, and liquid is injected into the battery cell shell through the liquid injection hole 40; the pressure relief piece 50 is an explosion-proof valve or an explosion-proof mark, and the pressure relief piece 50 opens when the battery cell fails and generates gas to avoid explosion of the battery cell; the lower plastic 60 is installed on the side of the minimalist cover facing the battery cell pole group; the sealing piece 70 is formed as an annular sealing ring structure to be sleeved on a part of the side wall of the pole 11.

[0079] This application divides the top cover sheet 20 into a shrinkage area 21 and a non-shrinkage area 22, and increases the deformation margin of the shrinkage area 21 based on the preset size to ensure that after the pole assembly 10 is welded to the top cover sheet 20, the actual size of each part of the top cover sheet 20 in the first direction D1 and the second direction D2 meets the preset size requirements. Specific experimental verification is as follows:

[0080] Experiment 1: As shown in FIG3 , the parameter of the preset dimension Y0 of the top cover sheet 20 in the second direction D2 is 28±0.05mm, which is within the parameter limit range of (11+A)±(0.03~0.08)mm and A≥0. Two pole assemblies 10 are provided on the top cover sheet 20, and two shrinkage areas 21 are provided correspondingly; along the first direction D1, the non-shrinkage area 22 is provided between the two shrinkage areas 21, and the shrinkage area 21 on the left side of the top cover sheet 20 in the second direction D2 is set to Y1, and the shrinkage area 21 on the right side is set to Y2 in the second direction D2, and the size of the non-shrinkage area 22 in the second direction D2 is Y3, in Experiment 1, t2 is 2 mm, 3 mm, and 4.5 mm, respectively, and the corresponding second deformation allowance L2=1 / [(12-18)t2] has a value range of 0.028-0.042 mm, 0.019-0.028 mm, and 0.012-0.019 mm, respectively; the parameters Y1, Y2, and Y3 before and after welding the pole assembly 10 and the top cover sheet 20 are measured, and compared with the examples of the prior art in which the width of the cover sheet is abnormal due to welding the pole to the bare aluminum sheet. The comparison results are shown in Tables 1 to 3:

[0081] Table 1 Dimensional parameters of Y1, Y2 and Y3 in the second direction D2 before and after welding when t2 = 2 mm

[0082] Table 2 Dimensional parameters of Y1, Y2 and Y3 in the second direction D2 before and after welding when t2 = 3 mm

[0083] Table 3 Dimensional parameters of Y1, Y2 and Y3 in the second direction D2 before and after welding when t2 = 4.5 mm

[0084] Note: The parameters of Y1, Y2 and Y3 in Comparative Examples 1 and 2 are the same as the measurement positions and / or measurement methods of Y1, Y2 and Y3 in Experiment 1.

[0085] Referring to Tables 1 to 3, it can be seen that in Experiment 1: the sizes of Y1 and Y2 before welding are increased by deformation allowances in the range of 0.028~0.042mm, 0.019~0.028mm, and 0.012~0.019mm respectively on the basis of Y0, so that the sizes of Y1 and Y2 before welding are larger than the size of Y3, and the size of the shrinkage zone 21 after welding changes, so that the sizes of Y1 and Y2 after welding are smaller than the sizes of Y1 and Y2 before welding, and the sizes of Y1 and Y2 after welding are similar to the sizes of Y3 before or after welding, respectively. This proves that the limitation of the second deformation allowance L2 to 1 / [(12~18)t2] can ensure that the width size consistency of the top cover sheet 20 at various locations in the length direction (i.e., the first direction D1) after welding is high, thereby meeting the welding requirements of the minimalist cover plate and the battery cell shell.

[0086] In Comparative Example 1 or Comparative Example 2, the sizes of Y1, Y2 and Y3 are similar before welding, while the sizes of Y1 and Y2 after welding are reduced compared to the sizes of Y1 and Y2 before welding, and the sizes of Y1 and Y2 after welding are smaller than the size of Y3, which affects the dimensional accuracy and shape accuracy, resulting in the problem of excessive local gap between the cover plate of Comparative Example 1 or Comparative Example 2 and the battery cell shell when assembled, resulting in a higher risk of poor welding.

[0087] Experiment 2: As shown in FIG4 , the parameter of the preset dimension X0 of the top cover sheet 20 in the first direction D1 is 160±0.05 mm, which is within the parameter limit range of (40+B)±(0.03-0.08) mm and B≥0; along the second direction D2, the pole assembly 10 is arranged in the middle position of the top cover sheet 20, and the corresponding shrinkage area 21 is located in the middle position of the top cover sheet 20 in the second direction D2, and the non-shrinkage area 22 is provided at two locations and is respectively located on both sides of the shrinkage area 21 in the second direction D2; wherein the dimension of the shrinkage area 21 in the first direction D1 is X1, and the non-shrinkage area 22 located above the shrinkage area 21 in the first direction from the perspective of FIG4 is X1. The dimension on D1 is X2, and the dimension of the contraction zone 21 located below in the first direction D1 is X3. In Experiment 2, t1 is 2.5 mm, 3.5 mm, and 4.5 mm, respectively, and the corresponding first deformation margin L1=1 / [(12-18)t1] has a value range of 0.022-0.033 mm, 0.016-0.024 mm, and 0.012-0.018 mm, respectively. The parameters X1, X2, and X3 before and after welding the pole assembly 10 and the top cover sheet 20 are measured, and compared with examples of the prior art in which the length of the cover plate is abnormal due to welding the pole to the bare aluminum sheet. The comparison results are shown in Tables 4 to 6:

[0088] Table 4 Dimensional parameters of X1, X2 and X3 in the first direction D1 before and after welding when t1 = 2.5 mm

[0089] Table 5 Dimensional parameters of X1, X2 and X3 in the first direction D1 before and after welding when t1 = 3.5 mm

[0090] Table 6 Dimensional parameters of X1, X2 and X3 in the first direction D1 before and after welding when t1 = 4.5 mm

[0091] Note: The parameters of X1, X2 and X3 in Comparative Examples 3 and 4 are the same as the measurement positions and / or measurement methods of X1, X2 and X3 in Experiment 2.

[0092] As shown in Table 2, in Experiment 2, the size of X1 before welding is increased by deformation allowances in the range of 0.022-0.033 mm, 0.016-0.024 mm, and 0.012-0.018 mm on the basis of X0, so that the size of X1 before welding is larger than the size of X2 or X3 before welding, and the size X1 of the shrinkage zone 21 after welding changes, so that the size of X1 after welding is smaller than the size of X1 before welding, and the size of X1 after welding is similar to the size of X2 or X3 before or after welding. This further proves that the limitation of the first deformation allowance L1 to 1 / [(12-18)t1] can ensure that the length dimension of the top cover sheet 20 after welding is highly consistent at various locations in the width direction (i.e., the second direction D2), thereby meeting the welding requirements of the minimalist cover plate and the battery cell shell.

[0093] In Comparative Example 3 or Comparative Example 4, the sizes of X1, X2 and X3 are similar before welding, but the size of X1 after welding is reduced compared to the size of X1 before welding, and the size of X1 after welding is smaller than the size of X2 or X3, which affects both the dimensional accuracy and the shape accuracy, resulting in a higher risk of poor welding of the cover plate and the battery cell shell in Comparative Example 3 or Comparative Example 4.

[0094] It should be noted that in Experiment 1 and Experiment 2, there are differences in the measured parameters of the non-contraction zone 22 before and after welding. This is due to measurement errors and is unavoidable.

[0095] According to a minimalist cover plate provided by the present application, by dividing the top cover plate into a shrinkage area and a non-shrinkage area and leaving a deformation margin in the shrinkage area, it is ensured that after the pole assembly is welded to the top cover plate, the actual size of the top cover plate in the first direction and the second direction is the same as the preset size. In this way, it is ensured that the minimalist cover plate and the battery cell shell can be assembled tightly, avoiding excessive local gaps around the shrinkage area, ensuring the consistency and yield of the minimalist cover plate size, thereby reducing the risk of poor welding between the minimalist cover plate and the battery cell shell and ensuring the welding quality.

[0096] According to a battery cell provided in the present application, there will not be excessive local gaps around the shrinkage area between the battery cell shell and the minimalist cover before welding, thereby ensuring reliable welding between the shell and the minimalist cover, avoiding leakage of the battery cell due to poor welding, thereby effectively improving the battery yield, and effectively improving production efficiency and saving costs when the battery cells are mass-produced.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application. Industrial Applicability

[0098] The minimalist cover plate and battery cell provided in the present application can ensure that after the pole assembly is welded to the top cover plate, the actual dimensions of the top cover plate in the first direction and the second direction are the same as the preset dimensions. This avoids excessive gaps between the shrinkage area of ​​the minimalist cover plate and the local gaps around the battery cell shell, thereby reducing the risk of poor welding and ensuring the quality of the battery cell.

Claims

1. A minimalist cover plate, characterized in that, The minimalist cover plate includes: A pole column assembly; A top cover sheet, which is welded to the pole column assembly. A welding track is formed between the top cover sheet and the pole column assembly. The top cover sheet includes a shrinkage zone and a non-shrinkage zone, and the welding track is located in the shrinkage zone; Before welding, the dimension of the shrinkage zone in the first direction is the sum of the preset dimension of the top cover sheet in the first direction and the first deformation allowance. The first deformation allowance is 1 / [(12 - 18)t1], where t1 is the distance from the pole column assembly to the edge of the top cover sheet in the first direction; the dimension of the shrinkage zone in the second direction is the sum of the preset dimension of the top cover sheet in the second direction and the second deformation allowance. The second deformation allowance is 1 / [(12 - 18)t2], where t2 is the distance from the pole column assembly to the edge of the top cover sheet in the second direction.

2. The minimalist cover plate according to claim 1, characterized in that, The top cover sheet is formed into a rectangular structure.

3. The minimalist cover plate according to claim 1 or 2, characterized in that The first direction is the length direction of the rectangular structure, and the second direction is the width direction of the rectangular structure.

4. The minimalist cover plate according to any one of claims 1 to 3, characterized in that ,, The length dimension of the top cover sheet is (40 + B) ± (0.03 - 0.08) mm, where B ≥ 0.

5. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, The width dimension of the top cover sheet is (11 + A) ± (0.03 - 0.08) mm, where A ≥ 0.

6. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, The second deformation allowance is not less than the first deformation allowance.

7. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, The axis of the welding track is located at the middle position of the shrinkage zone, and the axis extends along the third direction.

8. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, The shrinkage zone and the non-shrinkage zone are arranged at intervals; The top cover sheet further includes: A transition zone, which is arranged between the shrinkage zone and the non-shrinkage zone.

9. The minimalist cover plate according to any one of claims 1 to 3, characterized in that The dimensions of different parts of the shrinkage zone are different, and the dimension of the shrinkage zone increases as the welding track approaches the edge of the top cover sheet.

10. The minimalist cover plate according to any one of claims 1 to 3, characterized in that t1 is 2 mm to 15 mm.

11. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, t2 is 2 mm to 25 mm.

12. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, At least one pole column assembly is provided; when multiple pole column assemblies are provided, the multiple pole column assemblies are arranged at intervals along the first direction, the welding tracks are arranged in one-to-one correspondence with the pole column assemblies, and the non-shrinkage zone is arranged between adjacent welding tracks.

13. The minimalist cover plate according to claim 12, wherein Along the first direction, the dimension of the non-shrinkage zone is not less than the dimension of the adjacent shrinkage zone.

14. The minimalist cover plate according to any one of claims 1 to 3, characterized in that, The pole column assembly includes: A pole column; A support member, which is formed into an annular structure and sleeved on the side of the pole column body. The support member is welded to the top cover sheet; An insulating member, which is arranged between the support member and the top cover sheet.

15. A battery cell, characterized in that, Including the minimalist cover plate according to any one of claims 1 to 14.

Images