Battery cell top cover structure and battery cell

Abstract

The utility model provides a battery cell top cover structure and a battery cell. The battery cell top cover structure comprises a cover plate assembly, the electrode terminal is arranged on the cover plate assembly; the electrode terminal comprises a column body penetrating through the cover plate assembly and a pole bottom plate connected to one end of the column body; the at least two groups of tabs oppositely extend in a direction parallel to the pole bottom plate, and are at least partially overlapped to form an overlapped region; the at least two groups of tabs are welded on the pole bottom plate through welding marks, and the welding marks are at least partially positioned in the overlapping area; the at least two groups of tabs are partially overlapped to form the overlapped region, and the overlapped region is welded to the second connecting part through the welding print, so that the overall area of the welding print is increased, the welding strength for connecting the tabs and the second connecting part is improved, the probability of cracking or failure of the battery cell under the working condition of impact or vibration is reduced, and the quality of the battery cell is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery cell, in particular to a battery cell top cover structure and a battery cell. BACKGROUND

[0002] As a basic unit of energy storage system, the square shell battery cell has a complex internal structure and a relatively complicated assembly process. In the battery cell, the tab of the electrode assembly is connected to the pole post bottom plate of the electrode terminal in a welding form, and an electrical connection relationship is established between the pole post extending to the outside of the battery cell and the electrical equipment. In the battery cell, the tabs of the electrode assembly are usually connected to the pole post bottom plate in a grouped form, that is, each group of tabs forms a welding mark and realizes welding between the tabs and the pole post bottom plate. However, due to the dispersed connection between the tabs and the pole post bottom plate, the welding mark formed between the tabs and the pole post bottom plate has a small size and low mechanical strength, and the probability of cracking or failure under the condition of impact is relatively high, which affects the overall performance and quality of the battery cell. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the present application aims to provide a battery cell top cover structure and a battery cell to solve the above-mentioned technical problems.

[0004] In order to achieve the above purpose, the present application provides a battery cell top cover structure, which comprises:

[0005] a cover plate assembly;

[0006] an electrode terminal arranged in the cover plate assembly, the electrode terminal comprising a pole post extending through the cover plate assembly and a pole post bottom plate connected to one end of the pole post;

[0007] at least two groups of tabs, the at least two groups of tabs extending in opposite directions parallel to the pole post bottom plate and at least partially overlapping to form an overlapping area, the at least two groups of tabs being welded to the pole post bottom plate by a welding mark, and the welding mark being at least partially located in the overlapping area.

[0008] Based on the same inventive concept, the present application also provides a battery cell comprising the battery cell top cover structure as described above.

[0009] As can be seen from the above, the battery cell top cover structure and the battery cell provided by the present application can make the at least two groups of tabs form an overlapping area by overlapping and extending in opposite directions, increase the contact area between the overlapping area and the pole post bottom plate, increase the welding mark area of the overlapping area and the pole post bottom plate, improve the firmness and mechanical strength of the tabs and the pole post bottom plate after welding, and reduce the probability of cracking or failure of the welding mark, which is beneficial to improve the quality of the battery cell and prolong its service life. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0011] Figure 1 A schematic diagram of the connection between the pole plate and the tab in the related art;

[0012] Figure 2 A schematic diagram of the top cover structure of the battery cell in the present application;

[0013] Figure 3 A schematic diagram of the connection between the pole plate and the tab in one case in the present application;

[0014] Figure 4 A schematic diagram of the connection between the pole plate and the tab in another case in the present application;

[0015] Figure 5 A schematic diagram of the thinning area in the pole plate in the present application.

[0016] Explanation of reference signs:

[0017] 100, cover plate assembly;

[0018] 200, electrode terminal; 210, column body; 220, pole plate; 221, first connecting part; 222, second connecting part; 2221, thinning area; 223, welding mark; 2231, sub welding mark;

[0019] 300, tab;

[0020] 400, protective sheet;

[0021] 500, shell. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the specific embodiments and the accompanying drawings.

[0023] It should be noted that the technical terms or scientific terms used in the embodiments of the present application should be understood as the general meaning understood by those skilled in the art to which the present application belongs, unless otherwise defined. The terms "first", "second", and the like used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and the like mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] In the field of energy storage, especially for the design and manufacture of can-type battery cells, the reasonable assembly and reliable electrical connection of electrode assemblies are crucial to the overall performance and life of the battery cell; generally, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet and the negative electrode sheet are connected by welding technology to connect the respective corresponding tab 300 (i.e. the lead-out wire) and the pole column bottom plate 220 of the electrode terminal 200 provided by the cover plate assembly 100, to establish an electrical connection path from the electrode assembly to the pole column bottom plate 220 to the pole column 210 of the cover plate assembly 100; as shown in Figure 1 Figure 1 is a schematic view of the connection between the pole column bottom plate 220 and the tab 300 in the related art. In view of the fact that the battery cell often contains multiple electrode assemblies, the multiple electrode assemblies are usually connected by welding according to a specific grouping mode, and each group of tabs 300 will form a corresponding welding area on the side of the pole column bottom plate 220 away from the cover plate assembly 100, as the current collector for the connection between the tab 300 and the gasket plate of the pole column 210.

[0025] Although the welding technology is used to connect the tab 300 and the pole column bottom plate 220, it will reduce the connection difficulty between the two, but still has obvious disadvantages; specifically, since the corresponding tabs 300 of multiple electrode assemblies are distributed relatively dispersedly, the welding mark 223 formed after the connection of the tab 300 and the pole column bottom plate 220 has a relatively small area, and the small area of the welding mark 223 not only limits the mechanical strength, but also increases the risk of cracking or failure of the connection area when subjected to external impact or vibration, affecting the stability and service life of the battery cell.

[0026] ​To improve the strength of the weld formed between the tab 300 and the pole plate 220, a protective sheet 400 can be added on the side of the tab 300 away from the cover plate assembly 100 when welding the tab 300 and the pole plate 220, so as to increase the strength of the weld 223 through the protective sheet 400 and provide additional physical protection; although the stability of the weld 223 is increased by adding the protective sheet 400, new problems are introduced in actual application; specifically as shown in Figure 1 When the tabs 300 of the plurality of electrode assemblies and the pole plates 220 are welded and assembled into the battery cell housing 500, the part of the tab 300 between the electrode assembly and the pole plate 220 will switch from a flat state to a bent state, the distance between the weld 223 for connecting the tab 300 to the pole plate 220 and the inner side wall of the housing 500 is small, and the edge area of the protective sheet 400 is easy to abut against the surface of the tab 300. Since the protective sheet 400 is formed of copper or aluminum or other metal materials and has a relatively thin thickness, the part acting on the surface of the tab 300 can cause scratches or cuts on the tab 300, and in severe cases, the tab 300 can be cut off by the protective sheet 400, thereby affecting the yield and product quality of the battery cell.

[0027] In summary, how to effectively solve the problems of insufficient welding strength between the tab 300 and the pole plate 220 and damage to the tab 300 by the protective sheet 400 has become a key factor to improve the performance and reliability of the battery cell.

[0028] Therefore, the present application provides a battery cell top cover structure, which comprises a cover plate assembly 100, an electrode terminal 200, and at least two groups of tabs 300; the electrode terminal 200 is arranged on the cover plate assembly 100; the electrode terminal 200 comprises a column 210 penetrating through the cover plate assembly 100 and a pole plate 220 connected to one end of the column 210; the at least two groups of tabs 300 extend in parallel to the pole plate 220 and at least partially overlap to form an overlapping area; the at least two groups of tabs 300 are welded to the pole plate 220 by a weld 223, and the weld 223 is at least partially located in the overlapping area.

[0029] Therefore, specifically, please refer to Figure 2 and Figure 3 , Figure 2 is a schematic view of the battery cell top cover structure in the present application, Figure 3 is a schematic view of the connection between the pole plate 220 and the tab 300 in one case in the present application, Figure 4 is a schematic view of the connection between the pole plate 220 and the tab 300 in another case in the present application.

[0030] The present application provides a battery cell top cover structure with high reliability, which is applied to a battery cell; as Figure 2 and Figure 3As shown, the pole plate 220 includes a cover plate assembly 100, for the battery cell, the cover plate assembly 100 is embedded at the opening of the shell 500 of the battery cell, the electrode assembly is located in the shell 500 and immersed in the electrolyte; the cover plate assembly 100 is located above the electrode assembly, which can seal and protect the shell 500, and prevent the electrolyte from leaking; in addition, the cover plate assembly 100 is also provided with a safety valve and an electrode terminal 200, the electrode terminal 200 includes a column 210 penetrating the cover plate assembly 100 and a pole plate 220 connected to one end of the column 210, the safety valve can be used for safe pressure relief when the battery cell is abnormal, and the column 210 and the pole plate 220 connected to each other can be electrically connected with the positive or negative tab 300 of the electrode assembly, thereby establishing an electrical connection relationship with the external device.

[0031] For the tab 300, the tab 300 is the leading part of the positive and negative electrode sheet, and the battery cell of the multi-electrode assembly includes a plurality of corresponding tabs 300; wherein the battery cell top cover structure can divide the same type of multiple tabs 300 (i.e. positive or negative tabs) into at least two groups, and at least one tab unit is arranged in each group; when the tab 300 is welded on the surface of the pole plate 220, at least two groups of tabs 300 can be bent towards opposite directions, and the extension directions of at least two groups of tabs 300 are opposite to each other, so that at least two groups of tabs 300 at least partially overlap and form an overlapping area; during the welding process, the overlapping area formed by the at least two groups of tabs 300 is placed on the side of the pole plate 220 away from the cover plate assembly 100, so that the overlapping area has sufficient contact area with the corresponding pole plate 220.

[0032] In addition, when the welding mark 223 is formed, at least part of the welding mark 223 can be located in the overlapping area, so that the welding mark 223 formed between the overlapping area and the pole plate 220 has a larger size; as the welding area of the welding mark 223 increases, the connection strength between the tab 300 and the pole plate 220 also increases; compared with the distributed welding of the tab 300 in the related art, since at least two groups of tabs 300 are stacked and distributed in the present application, the welding mark area formed between the overlapping area and the pole plate 220 is relatively large, so that the connection between the pole plate 220 and the tab 300 is greatly enhanced, the probability of cracking or failure of the welding seam when subjected to external impact or vibration is reduced, the overall quality of the battery cell is improved, and the service life is prolonged.

[0033] In some embodiments, the pole plate 220 includes a first connecting portion 221 and a second connecting portion 222; at least part of the first connecting portion 221 is connected with the column 210; the second connecting portion 222 extends towards the middle area of the cover plate assembly 100 relative to the first connecting portion 221; the overlapping area is welded to the second connecting portion 222 by the welding mark 223.

[0034] The top cover structure of the battery cell further comprises a pole post bottom plate 220, as shown in Figure 2 and Figure 3 For the pole post bottom plate 220, the pole post bottom plate 220 can comprise a first connecting part 221 and a second connecting part 222 connected to each other, wherein the first connecting part 221 can be integrally formed with the pole body 210 of the electrode terminal 200 or connected by welding, so that at least part of the first connecting part 221 is connected with the pole body 210 and an electrical connection relationship is established between the pole body 210 and external equipment through the pole body 210; the second connecting part 222 is arranged to extend towards the central area of the cover plate assembly 100, so that the pole post bottom plate 220 forms a "convex" type structure, and the second connecting part 222 provides a connecting area for the overlapping area formed by the at least two groups of tabs 300, thereby enabling the at least two groups of tabs 300 to be concentratedly welded.

[0035] In addition, compared with the pole post bottom plate 220 in the related art, the pole post bottom plate 220 formed by the first connecting part 221 and the second connecting part 222 has a "convex" type structure, which can reduce the volume of the pole post bottom plate 220 and reduce the material usage and cost investment for forming the pole post bottom plate 220, thereby facilitating the lightweight design of the pole post bottom plate 220.

[0036] In combination with the above embodiments, the tabs 300 are further described as follows. When the tabs 300 are provided in two groups, each group of tabs 300 can comprise a plurality of tab monomers, and the two groups of tabs 300 can be sequentially stacked in whole or can be spacedly stacked, so as to reduce the stacking difficulty of the two groups of tabs 300 and to enable the two groups of tabs 300 after welding to have a higher connection strength, which will not be described herein again.

[0037] In some embodiments, along a direction perpendicular to the extension direction of the tabs 300, the width of the second connecting part 222 is smaller than the width of the first connecting part 221.

[0038] For the pole post bottom plate 220, the pole post bottom plate 220 comprises the first connecting part 221 connected to the pole body 210 and the second connecting part 222 extending away from the first connecting part 221, as shown in Figure 3 The second connecting part 222 extends away from the first connecting part 221, so as to provide a connecting position for the overlapping area; along the extension direction of the tabs 300, the width of the second connecting part 222 is set to be smaller than the width of the first connecting part 221, so that the two groups of tabs 300 after stacking are connected to the second connecting part 222 through at least part of the welding marks 223, so as to establish an electrical connection relationship between the electrode assembly and the pole body 210; at the same time, this design also reduces the material usage of the pole post bottom plate 220, that is, while ensuring a good connection effect between the pole post bottom plate 220 and the tabs 300, the cost of the pole post bottom plate 220 is also reduced.

[0039] Further, after the welding of the pole lug bottom plate 220 and the tab 300 is completed, the electrode assembly needs to be assembled in the shell 500, and the cover plate assembly 100 can be assembled in the opening of the shell 500 at the same time. Since the first connecting part 221 and the second connecting part 222 form a "convex" structure, after the electrode assembly is assembled into the shell 500, the distance between the welding mark 223 and the inner wall of the shell 500 is increased, which can reduce the bending degree of the tab 300 between the welding mark 223 and the electrode assembly, and provide a larger redundant movement space for part of the tab 300, thereby preventing the end of the tab 300 from being inserted.

[0040] Further, if the top cover structure of the battery cell also has the protection sheet 400, since the width of the second connecting part 222 is set to be smaller than the width of the first connecting part 221, and the second connecting part 222 and the first connecting part 221 form a "convex" structure, at this time, the distance between the welding mark 223 arranged in the second connecting part 222 and the inner wall of the shell 500 is relatively large, and the bending degree of the tab 300 is relatively large. Therefore, the edge region of the protection sheet 400 and the surface of the tab 300 are far away from each other, thereby effectively reducing the probability that the tab 300 is cut or damaged by the protection sheet 400.

[0041] In some embodiments, the overlapping region at least partially overlaps the projection of the pole lug bottom plate 220 and the projection of the pole 210 on the pole lug bottom plate 220.

[0042] For the electrode terminal 200, the pole 210 in the electrode terminal 200 is connected with the tab 300 through the pole lug bottom plate 220, so as to form an electrical connection between the battery cell and an external device. By making the overlapping region at least partially overlap the projection of the pole lug bottom plate 220 and the projection of the pole 210 on the pole lug bottom plate 220, the overall size of the pole lug bottom plate 220 can be further controlled, the cost and volume of the pole lug bottom plate 220 can be reduced, and the pole lug bottom plate 220 has sufficient area to form a reliable connection relationship between the pole 210 and the tab 300, respectively.

[0043] In some embodiments, the welding mark 223 includes at least one sub-welding mark 2231, and the overlapping region is at least one sub-welding mark 2231 welded on the side of the second connecting part 222 away from the cover plate assembly 100 by laser welding.

[0044] Specifically, please refer to Figure 4 , Figure 4 is a schematic view of the connection between the pole lug bottom plate 220 and the tab 300 in another case in the present application.

[0045] For the welding mark 223, since the two groups of the tab 300 have a large contact area with the same second connecting part 222, the overlapping area can be welded to the second connecting part 222 by the welding mark 223, and the size of the welding mark 223 used to connect the two is relatively large, so the connection strength is also relatively high; as Figure 4 shown, the welding mark 223 provided on the second connecting part 222 can include at least one sub-welding mark 2231, and the overlapping area is welded to the side of the second connecting part 222 away from the cover plate assembly 100 by the at least one sub-welding mark 2231. The sub-welding mark 2231 can be provided one or more than two; wherein by dividing the welding mark 223 into multiple sub-welding marks 2231, the welding stress of the welding mark 223 can be dispersed, the uniformity of the connection between the tab 300 and the second connecting part 222 can be improved, and the firmness and stability of the welding between the overlapping area and the second connecting part 222 can be improved; in addition, since each sub-welding mark 2231 has good independence, when one of the sub-welding marks 2231 cracks or fails, the interference degree on other sub-welding marks 2231 can be reduced, so as to prevent the normal use of the battery cell affected by the local failure of the welding mark 223.

[0046] In addition, when the overlapping area is welded to the side of the second connecting part 222 away from the cover plate assembly 100 by the at least one sub-welding mark 2231, laser welding technology can be used to weld the overlapping area and the second connecting part 222, such as laser spot welding; since laser welding technology has the advantages of high precision and high energy density, it can be suitable for welding small size parts, and suitable for local heating of parts, and can form a small and firm weld after welding, which is beneficial to improve the welding quality and efficiency, reduce the heat affected zone of the weld, reduce the deformation degree of the material, and improve the production yield and overall performance of the battery cell.

[0047] In some embodiments, the sub-welding mark 2231 is long strip-shaped, the extension direction of the sub-welding mark 2231 is the same as the extension direction of the second connecting part 222, and is perpendicular to the extension direction of the two groups of the tab 300.

[0048] For the welding mark 223, by dividing the welding mark 223 into multiple sub-welding marks 2231, the welding quality between the two groups of the tab 300 and the second connecting part 222 of the pole plate 220 can be improved; as Figure 4As shown, for the sub-welding mark 2231, by setting the sub-welding mark 2231 in a strip shape, the welding difficulty can be reduced so as to be welded by laser; at the same time, by making the extension direction of the sub-welding mark 2231 the same as the extension direction of the second connecting part 222 and perpendicular to the extension direction of the two groups of tabs 300, the plurality of sub-welding marks 2231 can be arranged in sequence along the extension direction of the tab 300, the area ratio of the sub-welding mark 2231 in the welding mark 223 in the overlapping area is improved, and problems such as local insufficient or uneven welding between the overlapping area and the second connecting part 222 are avoided.

[0049] In some embodiments, the ratio of the length of the welding mark 223 to the length of the second connecting part 222 along the extension direction of the second connecting part 222 is 1:1.3-1:1.5; and / or the ratio of the width of the welding mark 223 to the width of the second connecting part 222 along the direction perpendicular to the extension direction of the second connecting part 222 is 1:2.7-1:3.5.

[0050] For the second connecting part 222, the welding mark 223 is arranged in the second connecting part 222, and when the overlapping area and the second connecting part 222 are welded, the two can be connected through the welding mark 223; for example, in order to ensure that the overlapping area and the second connecting part 222 have sufficient contact area and the welding mark 223 has sufficient welding area, along the extension direction of the second connecting part 222, the ratio of the length of the welding mark 223 to the length of the second connecting part 222 can be set to 1:1.3-1:1.5, for example, when the minimum length of the welding mark 223 is 10 cm, the minimum length of the second connecting part 222 can be 13 cm, and the maximum length can be 15 cm; similarly, along the direction perpendicular to the extension direction of the second connecting part 222, the ratio of the width of the welding mark 223 to the width of the second connecting part 222 can be set to 1:2.7-1:3.5, for example: when the minimum width of the welding mark 223 is 6 cm, the minimum width of the second connecting part 222 can be 16.2 cm, and the maximum width can be 21 cm, which will not be described here.

[0051] In some embodiments, the second connecting part 222 is provided with a thinning area 2221 away from one side of the cover plate assembly 100, and the welding mark 223 is arranged in the thinning area 2221; the projection area of the overlapping area on the thinning area 2221 is less than or equal to the area of the thinning area 2221.

[0052] Specifically, please refer to Figure 5 , Figure 5 for the schematic view of the thinning area 2221 of the pole bottom plate 220 in this application.

[0053] For the second connecting portion 222, the second connecting portion 222 is provided with a welding mark 223, and the overlapping area is welded to the second connecting portion 222 through the welding mark 223 to increase the welding area therebetween; as shown in Figure 1 and Figure 5 By providing a thinning area 2221 on the side of the second connecting portion 222 away from the cover plate assembly 100 and arranging the welding mark 223 in the thinning area 2221, the heat input during welding of the second connecting portion 222 and the overlapping area can be reduced, the formation area of the heat affected zone and the degree of deformation of the material can be reduced, and the welding quality and consistency can be improved; in the thinning area 2221, by making the orthogonal projection area of the overlapping area on the thinning area 2221 less than or equal to the area of the thinning area 2221, it can be ensured that the end portions of at least two groups of the tabs 300 overlap in the thinning area 2221, it can be ensured that the overlapping area can be in full contact with the thinning area 2221 and fully welded, and it can be avoided that the tabs 300 are excessively extended at the end portions and the tabs 300 are inserted; since the thinning area 2221 is arranged on the second connecting portion 222, the overall quality of the second connecting portion 222 can be reduced, and the material consumption for forming the pole plate 220 can be further reduced, which is beneficial to realize the lightweight design of the battery cell and reduce the cost investment of the pole plate 220.

[0054] In addition, for the pole plate 220, the pole plate 220 is connected with the tabs 300 and the pole body 210 respectively, and is used to build an electrical connection relationship with external equipment; as shown in Figure 2 and Figure 5 Since the first connecting portion 221 and the second connecting portion 222 of the pole plate 220 both have internal resistance, along the direction perpendicular to the extension direction of the second connecting portion 222, the width of the second connecting portion 222 is smaller than the width of the first connecting portion 221 and has a “convex” structure, so that the internal resistance of the second connecting portion 222 is smaller than the internal resistance of the first connecting portion 221; on this basis, by arranging the thinning area 2221 on the second connecting portion 222, the size of the second connecting portion 222 can be further reduced, and the internal resistance of the second connecting portion 222 can be increased; when the battery cell is short-circuited, the current through the second connecting portion 222 increases instantaneously and the temperature of the second connecting portion 222 rises rapidly; since the second connecting portion 222 is relatively thin, when the temperature of the pole plate 220 is too high, the second connecting portion 222 with the thinning area 2221 is easy to be melted by high temperature, so that the battery cell stops supplying power or charging, which is beneficial to reduce the damage degree of the battery cell and improve the safety of the battery cell to prevent the risk of thermal runaway of the battery cell.

[0055] In some embodiments, along the thickness direction of the second connecting portion 222, the distance difference between the surface of the thinning area 2221 and the side of the first connecting portion 221 away from the cover plate assembly 100 is 0.2mm-0.5mm.

[0056] For the thinning area 2221, by setting the thinning area 2221 on the second connecting part 222, the consumables of the second connecting part 222 can be reduced, the welding effect can be optimized, and the overall performance and reliability of the battery cell can be improved; for example, as shown in Figure 5 the distance difference between the surface of the thinning area 2221 and the side of the first connecting part 221 away from the cover plate assembly 100 along the thickness direction of the second connecting part 222 is 0.2mm-0.5mm, that is, even if the thickness of the second connecting part 222 is smaller than that of the first connecting part 221, the second connecting part 222 still has good electrical conductivity and use strength, and the tab 300 and the second connecting part 222 can be fully connected during welding; when the battery cell is short-circuited, the temperature of the pole post bottom plate 220 rises sharply, and because the second connecting part 222 is thin, the pole post bottom plate 220 can be melted in time at high temperature, so that the battery cell has reliable safety.

[0057] In some embodiments, the battery cell top cover structure further comprises a protective sheet 400, which is welded to the side of the overlapping area away from the cover plate assembly 100, and the projection of the welding mark 223 on the pole post bottom plate 220 is located within the projection of the protective sheet 400 on the pole post bottom plate 220.

[0058] For the battery cell top cover structure, as shown in Figure 2 and Figure 3 by setting the protective sheet 400 on the side of the overlapping area away from the cover plate assembly 100, and making the projection of the welding mark 223 on the pole post bottom plate 220 located within the projection of the protective sheet 400 on the pole post bottom plate 220, the protective sheet 400 can cover and protect the weld between the tab 300 and the pole post bottom plate 220, which is beneficial to improve the mechanical strength of the weld, prevent the weld from cracking when subjected to external impact or vibration, and reduce the surface scratches of the tab 300 caused by bending during assembly, which is beneficial to ensure the overall performance and reliability of the battery cell.

[0059] The protective sheet 400 and the pole post bottom plate 220 are further described in combination with the above embodiments; the material of the protective sheet 400 can be selected according to the material of the tab 300 to meet the protection requirements of the weld and the normal use of the battery cell; for example, for the positive tab 300, the pole post bottom plate 220 connected to the positive tab 300, and the protective sheet 400 covering the positive tab 300, because the positive tab 300 is usually formed of aluminum material, the pole post bottom plate 220 and the protective sheet 400 can be formed of the same material as the positive tab 300, that is, formed of aluminum material, to ensure that they have similar thermal expansion coefficients and melting points, and avoid cracks or virtual welding problems caused by material property differences during welding.

[0060] Similarly, for the negative tab 300, the pole bottom plate 220 connected with the negative tab 300, and the protective sheet 400 covering the negative tab 300, since the negative tab 300 is usually formed of copper material, the pole bottom plate 220 and the protective sheet 400 can be formed of the same material as the positive tab 300, i.e., formed of copper material, which is conducive to ensuring the welding quality of the two, and the welding between the same materials is easier to achieve, and the strength of the welding seam formed is also higher.

[0061] Based on the same inventive concept, the application also provides an electric core, which comprises the electric core top cover structure described in any one of the above embodiments. Since the electric core comprises the electric core top cover structure described in any one of the above embodiments, the electric core has all the advantages and beneficial effects of the electric core top cover structure. For example, the electric core can be applied to lithium ion batteries, lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and sodium ion batteries, and the like, and will not be described here.

[0062] It should be noted that some embodiments of the application have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve desirable results. In certain implementations, multitasking and parallel processing can be advantageous.

[0063] Each of the embodiments in the present application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to.

[0064] The description of the present application is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the application to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Embodiments are chosen and described in order to best explain the principles of the application and its practical application, and to enable others skilled in the art to understand the application for various embodiments with various modifications as are suited to the particular use contemplated.

[0065] Those of ordinary skill in the art will understand that the discussion of any embodiment above is merely exemplary and is not intended to suggest that the scope of the application (including the claims) is limited to these examples; the embodiments or technical features among different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the aspects of the embodiments of the application as described above, which are not provided in detail for the sake of brevity.

[0066] While the present application has been described in connection with specific embodiments thereof, it will be understood that many modifications, substitutions, and changes will be apparent to those of ordinary skill in the art from the foregoing description.

[0067] Embodiments of the present application are intended to embrace all such alterations, modifications, and variations that fall within the scope of the appended claims. Accordingly, the application is intended to be governed by the scope of the claims and their equivalents.

Claims

1. An electrode top cap structure, characterized by, The application relates to a cover plate assembly and an electrode terminal. The electrode terminal comprises a column body penetrating through the cover plate assembly and a pole column bottom plate connected to one end of the column body. At least two groups of the pole ears oppositely extend in a direction parallel to the pole column bottom plate and at least partially overlap and form an overlapping area. The at least two groups of the pole ears are welded to the pole column bottom plate through a welding mark, and the welding mark is at least partially located in the overlapping area. The pole column bottom plate comprises a first connecting part and a second connecting part.

2. The cell top cover structure of claim 1, wherein, The first connecting part is at least partially connected to the column body.

3. The cell top cover structure of claim 2, wherein, The second connecting part extends towards a middle area of the cover plate assembly relative to the first connecting part.

4. The top cover structure of the battery cell according to claim 1, wherein The width of the second connecting part is smaller than the width of the first connecting part along the extension direction of the pole ears.

5. The cell top cover structure of claim 2, wherein, The overlapping area is at least partially overlapped with the pole column bottom plate and the column body in the pole column bottom plate.

6. The cell top cover structure of claim 5, wherein, The welding mark comprises at least one sub-welding mark.

7. The top cover structure of the battery cell according to claim 2, wherein The overlapping area is welded to the second connecting part away from the cover plate assembly through laser welding in at least one sub-welding mark. The sub-welding mark is in a strip shape.

8. The top cover structure of the battery cell according to claim 2, wherein The extension direction of the sub-welding mark is the same as the extension direction of the second connecting part and is perpendicular to the extension direction of the at least two groups of the pole ears.

9. The cell top cover structure of claim 8, wherein, The length ratio of the welding mark to the second connecting part is 1:1.3-1:1.5 along the extension direction of the second connecting part; and / or 10. An electric cell characterized by The width ratio of the welding mark to the second connecting part is 1:2.7-1:3.5 along the direction perpendicular to the extension direction of the second connecting part. The second connecting part away from the cover plate assembly is provided with a thinning area, and the welding mark is arranged in the thinning area. The overlapping area in the projection area of the thinning area is smaller than or equal to the area of the thinning area. The distance difference between the surface of the thinning area and the first connecting part away from the cover plate assembly is 0.2mm-0.5mm along the thickness direction of the second connecting part. The application further relates to a battery cell top cover structure comprising the electrode terminal.

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