Battery cell and battery

Abstract

A battery cell and a battery. The battery cell (10) comprises a battery cell main body; the battery cell main body comprises a main body part (100) and a plurality of tab structures (200); each tab structure (200) comprises a plurality of tabs (210) arranged on the same side of the main body part (100) in a first direction of the battery cell (10), each tab (210) being connected to the main body part (100); in each tab structure (200), some of the tabs (210) form a first tab group (201), while the other tabs (210) form a second tab group (202), and the first tab group (201) and the second tab group (202) are bent towards each other respectively at a first bending area (210a) and a second bending area (210b), and are stacked and connected to each other, the first bending area (210a) and the second bending area (210b) being spaced apart from each other in a second direction perpendicular to the first direction. Lower bending stresses are put on all of the first tab groups (201) and the second tab groups (202), such that the tab structures (200) occupy small spaces, helping to improve the energy density of batteries. The first tab groups (201) and the second tab groups (202) are more stable, effectively reducing the occurrence of abnormal situations, such as damage and breakage, of tabs (210) at joints of the first tab groups (201) and the second tab groups (202).

Description

A battery cell and a battery Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell and a battery. Background Art

[0002] With the growing demand for thinner and lighter electronic devices, controlling battery size and increasing battery energy density have become key research and development areas within the industry. Controlling the size of battery cells and reducing the proportion of space they occupy within the battery casing helps increase battery energy density, placing higher demands on the structural design of battery cells. Summary of the Invention

[0003] The embodiments of the present application provide a battery cell and a battery that can solve the problem of how to improve the battery cell structure and increase the battery energy density.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising a battery cell body, the battery cell body comprising: a main body portion and a tab structure; the tab structure comprising a plurality of tabs disposed on the same side of the main body portion along a first direction of the battery cell, each tab being connected to the main body portion;

[0005] Part of the tabs of the tab structure form a first tab group, and another part of the tabs form a second tab group. At least part of the tabs of the first tab group and at least part of the tabs of the second tab group extend from the main body toward directions away from each other, and all the tabs of the first tab group are bent toward each other at the first bending area and all the tabs of the second tab group are bent toward each other at the second bending area and stacked together. The first bending area and the second bending area are spaced apart in a second direction perpendicular to the first direction.

[0006] Based on the embodiments of the present application, the number of the first pole lug group and the number of the second pole lug group are smaller than the number of pole lugs bent in the entire pole lug structure in the prior art, so that the bending stress of the first pole lug group and the second pole lug group is smaller, which helps to reduce the rebound degree of the first pole lug group and the second pole lug group and reduce the space occupied by the pole lug structure.

[0007] In some exemplary embodiments, the tab includes a first section connected to the main body and a second section connected to the first section; one of the tabs in the first tab group is the first tab, and the connection between the first section and the second section of the first tab is located in the first bending region, and the other tabs in the first tab group extend to the first bending region and then bend toward the second tab group;

[0008] One of the pole tabs in the second pole tab group is the second pole tab, and at least one pole tab is provided between the second pole tab and the first pole tab. The connection between the first section and the second section of the second pole tab is located in the second bending area, and the other pole tabs in the second pole tab group extend to the second bending area and then bend toward the first pole tab group; the second section of the pole tab of the first pole tab group and the second section of the pole tab of the second pole tab group are stacked and connected in the first direction of the battery cell.

[0009] Based on the above embodiment, the tabs of both the first tab group and the second tab group are bent in appropriate areas, and the spacing between the two bending areas is set to prevent the bent tabs from being too wide and exceeding the main body in the second direction of the battery cell, thereby preventing the bent tabs from colliding with other structures.

[0010] In some exemplary embodiments, two adjacent tabs of the tab structure at least partially overlap in the second direction of the battery cell; along the second direction, the tab structure includes a middle tab, the middle tab and a plurality of tabs located on one side of the middle tab in the second direction form a first tab group, and a plurality of tabs located on the other side of the middle tab in the second direction form a second tab group.

[0011] Based on the above embodiment, the above bending method is adopted to enable two adjacent tabs to interact with each other after bending, thereby improving the orderliness of the tabs after bending, preventing the large bending stress of some tabs from rebounding and causing part of the tabs to protrude, thereby improving the regularity of the appearance of the tab structure and effectively improving the stability of the tab structure.

[0012] In some exemplary embodiments, in the second direction of the battery cell, the tab farthest from the middle tab in the first tab group forms the first tab; and / or, in the second direction of the battery cell, the tab farthest from the middle tab in the second tab group forms the second tab.

[0013] Based on the above embodiments, more tabs can be bent, so that the interaction force between the tabs of each tab structure is greater, the degree of freedom of the tab structure is reduced, and the stacking area of ​​the first tab group and the second tab group after being bent toward each other is larger, thereby providing a larger area for mutual connection.

[0014] In some exemplary embodiments, in the first direction, the second segment of the second tab group is stacked and connected with the second segment of the first tab group on the side away from the main body; or, all the second segments of the second tab group are inserted between the second segments of two adjacent tabs of the first tab group; or, all the second segments of the first tab group are inserted between the second segments of two adjacent tabs of the second tab group; or, a second segment of the first tab group is inserted between the second segments of two adjacent tabs of the second tab group.

[0015] Based on the above embodiment, the interaction force between the tabs of the first tab group and the tabs of the second tab group is increased, so that the connection between the stacked portions of the first tab group and the second tab group is more stable.

[0016] In some exemplary embodiments, the length of the main body in the second direction of the battery cell is A; the connection between the second segment and the first segment of the tab has a first boundary, and the end of the second segment away from the first segment has a second boundary;

[0017] In the second direction, the second edges of all tabs in the first tab group are spaced from the first edges of the tabs in the second tab group by a spacing of L1, where L1 satisfies the following: 0.1 mm ≤ L1 ≤ A / 2. When L1 is less than 0.1 mm, the ends of the second segments of the tabs in the first tab group may protrude excessively, causing the first tab group to contact other structures outside the battery cell. When L1 is greater than A / 2, the weld area of ​​the second segments of the two tab groups is small, affecting weld strength.

[0018] In the second direction, the second boundaries of all the tabs of the second tab group are spaced apart from the first boundaries of the tabs of the first tab group, and the spacing is L2, and L2 satisfies: 0.1 mm≤L2≤A / 2.

[0019] Based on the above embodiment, the second segment of the first tab group contacts the second tab group, thereby puncturing the second tab group and preventing the ends of the second segments of the tabs of the second tab group from protruding too much, thereby preventing the second tab group from contacting other structures outside the battery cell. When L2 is less than 0.1mm, the ends of the second segments of the tabs of the second tab group may protrude too much, causing the second tab group to contact other structures outside the battery cell. When L2 is greater than A / 2, the welding area of ​​the second segments of the two tab groups is small, affecting the welding strength.

[0020] In some exemplary embodiments, in the second direction, the spacing between the second boundaries of two adjacent tabs of the first tab group is x1, and x1 satisfies: 0mm≤x1≤0.5mm; and / or, in the second direction, the spacing between the second boundaries of two adjacent tabs of the second tab group is x2, and x2 satisfies: 0mm≤x2≤0.5mm.

[0021] Based on the above embodiment, the end of the second section of the first tab group and the end of the second section of the second tab group are made flush or nearly flush, so as to reduce the space occupied by the tab structure.

[0022] In some exemplary embodiments, the second segment of the first tab group has a first connection area, the second segment of the second tab group has a second connection area, and the second connection area is stacked with the first connection area in a first direction; the battery core also includes a solder layer, the solder layer covers the first connection area and the second connection area to electrically connect the first tab group and the second tab group.

[0023] Based on the above embodiment, welding is adopted to effectively connect the tabs of the first tab group and the tabs of the second tab group, and the connection stability is good.

[0024] In some exemplary embodiments, the tab has an inner surface, and the tab is bent toward the side where the inner surface is located; the inner surface of the tab includes a first surface, a portion of the surface of the first section forms the first surface, and the first surface is connected to the main body; the angle between the first surface of the middle tab and the second direction of the battery cell is β, and β satisfies: 5°≤β≤45°.

[0025] Based on the above embodiment, regarding the angle β between the first surface of the middle tab and the second direction of the battery cell, the angle β of the middle tab is the smallest relative to the angles β of other tabs. By controlling the angle β of the middle tab within the above range, it is convenient to reduce the size of the tab structure in the length direction of the battery cell.

[0026] In some exemplary embodiments, the inner surface of the tab includes a second surface, and a portion of the surface of the second section forms the second surface; the inner surface of a portion of the tab of the tab structure also includes a connecting transition surface connected between the first surface and the second surface; the connecting transition surface is an arc surface; or, at least a portion of the connecting transition surface is a plane, and the angle between the plane portion of the connecting transition surface of the middle tab and the second surface is α, and α satisfies: 90°≤α≤150°.

[0027] Based on the above embodiment, by controlling the bending angles between the segments of the tab to meet the above range, it helps to reduce the volume of the tab structure on the one hand, and prevents the tab from breaking due to excessive bending angles on the other hand.

[0028] In some exemplary embodiments, the number of the tabs in the first tab group is n1, and the number of the tabs in the second tab group is n2, wherein n1:n2=1:(1-5). Preferably, n1 and n2 satisfy: n1:n2=1:(1-1.2).

[0029] Based on the above embodiment, within the above ratio range, the number of tabs in the first tab group and the number of tabs in the second tab group are appropriately distributed, and the bending stress of the tab structure formed after bending is small.

[0030] In some exemplary embodiments, the battery cell includes two groups of tab structures, one group of tab structures is a positive tab structure and the other group of tab structures is a negative tab structure; the positive tab structure and the negative tab structure are arranged on the same side of the main body.

[0031] In a second aspect, an embodiment of the present application provides a battery, comprising a housing and the battery cell as described above, wherein the battery cell is disposed in an internal space of the housing.

[0032] Based on the battery cell and battery of the embodiment of the present application, by dividing the multiple tabs of the tab structure into two groups of tabs, a first tab group and a second tab group, and bending them toward each other and then stacking and connecting them, the number of the first tab group and the second tab group is less than the number of tabs bent in the entire tab structure in the prior art, so that the bending stress of each of the first tab group and the second tab group is smaller, which helps to reduce the rebound degree of the first tab group and the second tab group and reduce the space occupied by the tab structure, thereby improving the energy density of the battery when the battery cell is used in the battery. After the bending stress of both the first tab group and the second tab group is reduced, the stress at the connection between the first tab group and the second tab group is also reduced, and the connection between the two is more stable, effectively reducing abnormal conditions such as damage and breakage of the tabs at the connection between the first tab group and the second tab group. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0034] FIG1 is a schematic diagram of the three-dimensional structure of a battery cell according to an embodiment of the present application;

[0035] FIG2 is a partial cross-sectional schematic diagram of a battery cell according to an embodiment of the present application;

[0036] FIG3 is a schematic diagram of the front view of the unfolded pole piece according to an embodiment of the present application;

[0037] FIG4 is a partial cross-sectional schematic diagram of a battery cell according to another embodiment of the present application;

[0038] FIG5 is a partial cross-sectional schematic diagram of a battery cell according to an embodiment of the present application, with dimensions marked;

[0039] FIG6 is a partial cross-sectional view of a battery cell in the related art when multiple tabs are bent at one point;

[0040] FIG7 is a partial cross-sectional schematic diagram of a second tab group plugged into a first tab group according to an embodiment of the present application;

[0041] FIG8 is a partial cross-sectional schematic diagram of the second tab group and the first tab group being plugged into each other according to an embodiment of the present application;

[0042] FIG9 is a side view schematic diagram of a tab structure according to an embodiment of the present application.

[0043] Figure numerals: 10, battery cell; 100, main body; 200, tab structure; 201, first tab group; 202, second tab group; 210, tab; 211, first section; 212, second section; 2101, first boundary; 2102, second boundary; 2111, first connection area; 2112, second connection area; 203, intermediate tab; 204, first tab; 205, second tab; 210a, first bending area; 210b, second bending area; 2011, connection transition surface; 2013, first surface; 2014, second surface; X, first direction; Y, second direction; Z, third direction; 220, isolation membrane; 230, solder layer; 240, pole piece; 241, first part; 242, second part; 410, positive tab structure; 420, negative tab structure. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0045] The inventors have found that bending and stacking the tabs at the head of the battery cell can improve the orderliness of the tabs, which can improve space utilization and reduce the space occupied by the battery cell inside the battery. However, the tabs will rebound due to the bending stress, making it difficult to achieve a good effect on reducing the volume of the battery cell. In addition, it is difficult to insert the battery cell into the outer shell of the battery. In addition, after the multi-layer tabs are bent, they are connected by welding or other methods. The welding part will also take up space. Together with the bent multi-layer tabs, the size of the battery cell head is larger and limits the further reduction of the size of the battery cell head. The inventors also found that the stress at the edge and near the welding part of the bent tabs is greater, which makes it easy for the tabs to break near the welding part. Based on this, the embodiments of the present application provide a battery cell and a battery.

[0046] As shown in FIG1 , a schematic diagram of the structure of a battery cell 10 according to an embodiment of the present application is shown. The battery cell 10 includes a battery cell body, which includes a main body portion 100 and multiple sets of tab structures 200. As shown in FIG2 , the battery cell 10 includes multiple pole pieces 240 and a separator 220. The main body portion 100 is formed by at least a portion of the separator 220 and the pole pieces 240, and the tab structures 200 are provided on the pole pieces 240 or formed by a portion of the pole pieces 240.

[0047] Specifically, as shown in FIG3 , a schematic diagram of the structure of a pole piece 240 in an embodiment of the present application in an unfolded state is shown. When the pole piece 240 is in the unfolded state, it has a length direction, a width direction, and a thickness direction that are perpendicular to each other. Each pole piece 240 has a first portion 241 and a second portion 242. The first portion 241 is formed by a portion of the current collector and an active material layer provided on the surface of the current collector in the thickness direction of the pole piece 240. The second portion 242 is formed by another portion of the current collector and is located at the edge region of the pole piece 240 in the width direction of the pole piece 240. The current collector of the second portion 242 is integrally provided with the current collector of the first portion 241. The isolation membrane 220 is provided between the two pole pieces 240 of opposite polarity in the thickness direction of the pole piece 240 to separate the two pole pieces 240 of opposite polarity. The two pole pieces 240 and the separator 220 disposed between the two pole pieces 240 can be wound multiple times along the length direction of the pole piece 240 to form a wound battery cell body, or the pole pieces 240 and the separator 220 can be alternately stacked along the thickness direction of the pole piece 240 to form a laminated battery cell body. The pole piece 240 and the separator 220 form the main body 100, and the tab structure 200 is mounted on the second portion 242 of the pole piece 240. Alternatively, the first portion 241 of the pole piece 240 and the separator 220 form the main body 100, and the second portion 242 of the pole piece 240 forms the tab structure 200.

[0048] When the cell body is a wound cell body, each electrode 240 of the cell body is approximately racetrack-shaped. Specifically, each electrode 240 includes two oppositely disposed straight portions and two oppositely disposed corner portions, with the two corner portions connected to opposite ends of the two straight portions. The tab structure 200 is disposed on the electrode 240 corresponding to the straight portion.

[0049] Each tab structure 200 includes a plurality of tabs 210 arranged on the same side of the main body 100 in the first direction X of the battery cell 10. Each tab 210 is connected to the main body 100. Specifically, each tab 210 is installed on the main body 100, or each tab 210 is integrally arranged with the main body 100.

[0050] In the embodiment of the present application, the tabs 210 are bent to reduce the head size of the battery cell 10. It is understandable that each tab 210 is subjected to bending stress after being bent, which makes the tabs 210 prone to rebound. When the number of tabs 210 increases, after the multiple tabs 210 are bent, the bending stresses between the tabs 210 interact with each other, resulting in a more significant rebound stress in the entire group of tabs after being bent. In particular, in addition to the rebound of the outer tabs 210 themselves, the inner tabs 210 will also act on the outer tabs 210 due to the rebound stress, which will further aggravate the rebound of the outer tabs 210. In this way, not only will the tabs 210 of the tab group occupy a large space after being bent, but the bending stress will also easily cause stress at the connection between the tabs 210 and the tabs 210, resulting in unstable connection. In severe cases, it is also easy to cause abnormal conditions such as damage or breakage at the connection between the tabs 210 and the tabs 210, affecting the safety of the battery cell 10. In addition, due to the bending stress, the two adjacent tabs 210 may be unstable after being bent, making it difficult to align and connect multiple tabs 210 .

[0051] As shown in Figure 2, the present application sets a tab structure 200 in which a portion of the tabs 210 form a first tab group 201, and another portion of the tabs 210 form a second tab group 202. At least a portion of the tabs 210 of the first tab group 201 and at least a portion of the tabs 210 of the second tab group 202 extend from the main body 100 in directions away from each other, and all the tabs 210 of the first tab group 201 are bent toward each other at the first bending region 210a, and all the tabs 210 of the second tab group 202 are bent toward each other at the second bending region 210b and stacked together. The first bending region 210a and the second bending region 210b are spaced apart in a second direction Y perpendicular to the first direction X.

[0052] The embodiment of the present application can electrically connect the first tab group 201 and the second tab group 202 at their stacking position, resulting in a large stacking area, which helps to stabilize the electrical connection between the first tab group 201 and the second tab group 202. Specifically, by dividing the plurality of tabs 210 of the tab structure 200 into two groups of tabs, the first tab group 201 and the second tab group 202, and bending them toward each other and then stacking and connecting them, the number of the first tab group 201 and the number of the second tab group 202 are relatively small relative to the number of tabs 210 in the entire tab structure 200, resulting in smaller bending stress in each of the first tab group 201 and the second tab group 202, which helps to reduce the degree of rebound of the first tab group 201 and the second tab group 202, and reduce the space occupied by the tab structure 200, thereby improving the energy density of the battery when the battery cell 10 is used in the battery. After the bending stress of the first tab group 201 and the second tab group 202 is reduced, the stress at the connection between the first tab group 201 and the second tab group 202 also becomes smaller, and the connection between the two is more stable, effectively reducing abnormal situations such as damage and breakage of the tab 210 at the connection between the first tab group 201 and the second tab group 202.

[0053] Each tab 210 includes an integrally formed first section 211 and a second section 212. The first section 211 is connected to the main body 100, and the second section 212 is connected to the end of the first section 211 away from the main body 100. Each tab 210 is bent at the connection between the first section 211 and the second section 212. That is, the connection between the first section 211 and the second section 212 of the first tab group 201 is located in the first bending region 210a, and the connection between the first section 211 and the second section 212 of the second tab group 202 is located in the second bending region 210b. The second sections 212 of the tabs 210 of the first tab group 201 and the second sections 212 of the tabs 210 of the second tab group 202 are stacked and connected in the first direction X of the battery cell 20.

[0054] As shown in FIG2 , one of the tabs 210 in the first tab group 201 is the first tab 204. The connection between the first segment 211 and the second segment 212 of the first tab 204 is located in the first bending region 210a. The second segment 212 of the first tab 204 is bent toward the side where the second tab group 202 is located at the first bending region 210a. The other tabs 210 in the first tab group 201 extend to the first bending region 210a and then bend toward the second tab group 202. The first bending region 210a is the connection between the first segment 211 and the second segment 212 of the first tab 204 and the area near the connection. All the tabs 210 in the first tab group 201 are concentrated in the first bending region 210a for bending, and two adjacent tabs 210 in the first bending region 210a are arranged in close contact.

[0055] One of the tabs 210 in the second tab group 202 is the second tab 205. The connection between the first segment 211 and the second segment 212 of the second tab 205 is located in the second bending region 210b. The second segment 212 of the second tab 205 bends at the second bending region 210b toward the side where the first bending region 210a is located. The other tabs 210 in the second tab group 202 extend to the second bending region 210b and then bend toward the first tab group 201. Similarly, the second bending region 210b is the connection between the first segment 211 and the second segment 212 of the second tab 205 and the area near the connection. All the tabs 210 in the second tab group 202 are concentrated in the second bending region 210b and bend, and two adjacent tabs 210 in the second bending region 210b are arranged in a close relationship.

[0056] Optionally, the first section 211 of the first pole tab 204 extends along the first direction X of the battery cell 10, and the second section 212 extends along the second direction Y of the battery cell 10 toward the side where the second pole tab group 202 is located. The first section 211 of the second pole tab 205 extends along the first direction X of the battery cell 10, and the second section 212 extends along the second direction Y of the battery cell 10 toward the side where the first pole tab group 201 is located. At least one pole tab 210 is provided between the second pole tab 205 and the first pole tab 204. In this way, it is convenient to select a suitable bending position, so that the spacing between the first bending area 210a and the second bending area 210b in the second direction Y of the battery cell 10 is appropriate, and thus the area of ​​the second section 212 of the pole tab 210 of the first pole tab group 201 and the second section 212 of the pole tab 210 of the second pole tab group 202 in the first direction X of the battery cell 10 is appropriate, thereby improving the connection stability.

[0057] Optionally, two adjacent tabs 210 of the tab structure 200 at least partially overlap in the second direction Y of the battery cell 10. After the tabs 210 are bent, the electrical connection between the two adjacent tabs 210 can be made more stable. Preferably, the widths of the two adjacent tabs 210 of the tab structure 200 in the third direction Z of the battery cell 10 are equal, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. After the tabs 210 are bent, the two adjacent tabs 210 of the tab structure 200 overlap in the second direction Y of the battery cell 10, which helps to further improve the electrical connection stability of the two adjacent tabs 210 of the tab structure 200, and reduces the space occupied by each tab structure 200 in the third direction Z of the battery cell 10. The spacing between two adjacent groups of tab structures 200 is large, preventing the two adjacent groups of tabs 210 from contacting each other.

[0058] The tab structure 200 includes a middle tab 203. The middle tab 203 and a plurality of tabs 210 located on one side of the middle tab 203 in the second direction Y form a first tab group 201. The plurality of tabs 210 located on the other side of the middle tab 203 in the second direction Y form a second tab group 202. In this way, it is convenient to group the plurality of tabs 210 of the tab structure 200 in an orderly manner, reduce the interaction force between the tabs 210, and thereby reduce the rebound stress of the tab structure 200.

[0059] As shown in Figures 2 and 4, one of the pole tabs 210 in the first pole tab group 201 located on the side of the middle pole tab 203 away from the second pole tab group 202 forms the first pole tab 204. For example, in the second direction Y of the battery cell 10, the pole tab 210 of the first pole tab group 201 farthest from the middle pole tab 203 forms the first pole tab 204, or the penultimate pole tab 210 of the first pole tab group 201 away from the middle pole tab 203 forms the first pole tab 204.

[0060] One of the pole tabs 210 in the second pole tab group 202 that is located on the side of the middle pole tab 203 away from the first pole tab group 201 forms the second pole tab 205. For example, in the second direction Y of the battery cell 10, the pole tab 210 of the second pole tab group 202 that is farthest from the middle pole tab 203 forms the second pole tab 205, or the second to last pole tab 210 of the second pole tab group 202 that is farthest from the middle pole tab 203 forms the second pole tab 205.

[0061] The tabs 210 have inner surfaces, and each tab 210 is bent toward the side where its inner surface is located. As shown in Figure 5, the inner surface of the tab 210 includes a first surface 2013 and a second surface 2014. A portion of the surface of the first section 211 forms the first surface 2013, and the first surface 2013 is connected to the main body. The angle β between the first surface 2013 of the intermediate tab 203 and the second direction Y of the battery cell 10 is β. Specifically, at least a portion of the first surface 2013 of the intermediate tab 203 is planar, and the angle β is the angle between the planar portion of the first surface 2013 of the intermediate tab 203 and the second direction Y of the battery cell 10. β satisfies the following: 5°≤β≤45°. It can be understood that, with respect to the angle between the first surface 2013 and the second surface 2014 of each pole tab 210 in the pole tab structure 200, the angle β of the middle pole tab 203 is the smallest relative to the angles of the other pole tabs 210. By controlling the angle β of the middle pole tab 203 within the above range, it is convenient to reduce the size of the pole tab structure 200 in the first direction X of the battery cell 10.

[0062] The inner surface of the tab 210 further includes a second surface 2014, and a portion of the surface of the second section 212 forms the second surface 2014. The inner surface of a portion of the tab 210 of the tab structure 200 further includes a connecting transition surface 2011 connecting the first surface 2013 and the second surface 2014, and a portion of the surface of the first section 211 forms the connecting transition surface 2011. The first surface 2013 and the second surface 2014 of another portion of the tab 210 of the tab structure 200 are directly connected.

[0063] Optionally, the connection transition surface 2011 is an arcuate surface. In this case, the thickness of the tab structure 200 in the first direction X of the battery cell 10 is affected by the angle β of the intermediate tab 203. The smaller the angle β, the smaller the thickness of the tab structure 200 in the first direction X of the battery cell 10. Optionally, at least a portion of the connection transition surface 2011 is planar. In this case, the spacing between the first surface 2013 and the second surface 2014 of the intermediate tab 203 in the first direction X of the battery cell 10 can be easily adjusted to coordinate with other structural components and meet the installation requirements of other structural components. The angle between the planar portion of the connection transition surface 2011 of the intermediate tab 203 and the second surface 2014 is α. Specifically, at least a portion of the second surface 2014 of the intermediate tab 203 is planar, and the angle α is the angle between the planar portion of the second surface 2014 of the intermediate tab 203 and the planar portion of the connection transition surface 2011. Here, α satisfies: 90°≤α≤150°. It is understood that the greater the number of bent tabs 210 in a single tab 210 group, the greater the degree of rebound of the tab 210 due to bending stress. Therefore, controlling the angle α within a smaller range improves the effectiveness of the tab structure 200 in resisting rebound stress. Preferably, α satisfies: 90°≤α≤110°, making the tab structure 200 more compact and reducing the degree of freedom of the tab structure 200. More preferably, α is 90°, in which case the planar portion of the connection transition surface 2011 of the middle tab 203 is parallel to the first direction X of the battery cell 10.

[0064] The above is an introduction to the middle tab 203 in the tab structure 200. The angles between the first surfaces 2013 of the other tabs 210 of each tab structure 200 and the second direction Y of the battery cell 10 are all greater than β. Furthermore, some of the other tabs 210 of each tab structure 200 may or may not have a connection transition surface 2011. For example, as shown in Figure 4, if the angle between the first surface 2013 and the second surface 2014 of the outermost tab 210 of the tab structure 200 is greater than 90, then the first surface 2013 of the tab 210 is directly connected to the second surface 2014; if the angle between the first surface 2013 and the second surface 2014 of the tab 210 adjacent to the middle tab 203 is less than 90, then the first surface 2013 of the tab 210 is connected to the second surface 2014 through the connecting transition surface 2011, and the angle between the planar portion of the connecting transition surface 2011 and the second surface 2014 is greater than or equal to α.

[0065] The battery cell 10 further includes a solder layer 230 . The solder layer 230 is disposed at the stacking position of the second section 212 of the first tab group 201 and the second section 212 of the second tab group 202 , and solders the two together.

[0066] As shown in FIG5 , the thickness of the tab structure 200 in the first direction X of the battery cell 10 is equal to the first thickness m1 plus the second thickness m2. The first thickness m1 is the thickness of the portion where the tab 210 connects to the main body 100 (i.e., the first section 211 of the tab 210). The second thickness m2 is the thickness of the portion where the tabs 210 are connected to the main body 100 (i.e., the second section 212 of the tab 210) plus the thickness of the solder layer 230. It can be understood that the solution of the present application and the solution shown in FIG6 , in which all the tabs 210 are bent in the same area before being welded, are equal in terms of the second thickness m2. The difference between the solution of the present application and the solution in which all the tabs 210 are bent in the same area before being welded is that the first thickness m1 is different, and the first thickness m1 of the present application is thinner.

[0067] Specifically, taking the thickness of a single tab 210 as g, the number of tabs in the first tab group 201 as n1, and the number of tabs in the second tab group 202 as n2, the total number of tabs 210 in the tab structure 200 is n1 + n2. In the solution where all the tabs 210 are concentrated in the same area, bent and then welded, the second thickness m2 of the tab structure 200 is (n1 + n2)g; in the embodiment of the present application, the thickness of the stacked tabs 210 in the first tab group 201 is n1*g, and the thickness of the stacked tabs 210 in the second tab group 202 is n2*g. Since the first segments 211 of the tabs 210 in the first tab group 201 and the first segments 211 of the tabs 210 in the second tab group 202 are separated, and when the tab 210 farthest from the middle tab 203 in the first tab group 201 forms the first tab 204 and the tab 210 farthest from the middle tab 203 in the second tab group 202 forms the second tab 205, the second thickness m2 of the tab structure 200 in the present application is the larger of the two values of n1*g and n2*g. If n1 < n2, the second thickness m2 of the tab structure 200 in the present application is n2*g. It can be seen that compared with the solution where all the tabs 210 are concentrated in the same area, bent and then welded, the thickness reduction of the tab structure 200 in the solution of the present application is W, and W = (n1 + n2)g - n2*g = n1*g. When selecting the tabs 210 closer to the middle tab 203 as the first tab 204 and the second tab 205, the thickness reduction of the tab structure 200 in the embodiment of the present application can be smaller than n1*g. Therefore, the present application divides the multiple tabs 210 of the tab structure 200 into the first tab group 201 and the second tab group 202, which can not only reduce the size of the tab structure 200 by reducing the bending stress, but also reduce the thickness of the tabs 210 from the stacked thickness of the multiple tabs 210, truly optimizing the tab structure 200 to improve the energy density of the battery when the battery cell 10 is applied to the battery.

[0068] Optionally, the number n1 of the tabs 210 in the first tab group 201 and the number n2 of the tabs 210 in the second tab group 202 satisfy: n1:n2 = 1:(1 - 5). Distributing the number of tabs 210 in the first tab group 201 and the second tab group 202 according to this ratio makes the structures of the first tab group 201 and the second tab group 202 compact after bending, preventing the number of tabs 210 in the first tab group 201 or the second tab group 202 from being too large and causing excessive bending stress and rebound. Preferably, n1:n2 = 1:(1 - 1.2).

[0069] The number of the pole tabs 210 in the second pole tab group 202 is greater than the number of the pole tabs 210 in the first pole tab group 201. Optionally, as shown in FIG2 , in the first direction X, the second section 212 of the second pole tab group 202 is stacked and connected with the second section 212 of the first pole tab group 201 on the side away from the main body 100. Selecting the second pole tab group 202 with a larger number of pole tabs 210 to be located in the outer layer of the first pole tab group 201 helps to make full use of the space between the main body 100 and the outermost pole tabs 210, making the structure of the pole tab structure 200 more compact.

[0070] Alternatively, as shown in FIG7 , all second segments 212 of the second tab group 202 are inserted between the second segments 212 of two adjacent tabs 210 of the first tab group 201; or, all second segments 212 of the first tab group 201 are inserted between the second segments 212 of two adjacent tabs 210 of the second tab group 202; or, as shown in FIG8 , one second segment 212 of the first tab group 201 is inserted between the second segments 212 of two adjacent tabs 210 of the second tab group 202. The above-described plug-in connection method helps increase the contact area between the tabs 210 of the first tab group 201 and the second tab group 202, improves the stability of the connection between the first tab group 201 and the second tab group 202, and the plugged-in tabs 210 can interact with each other to prevent the individual tabs 240 from being damaged due to bending stress.

[0071] As shown in Figure 9, the second section 212 of the first tab group 201 has a first connection area 2111, and the second section 212 of the second tab group 202 has a second connection area 2112. The second connection area 2112 overlaps with the first connection area 2111 in the first direction X of the battery cell 10 and is electrically connected, wherein the projection of the solder layer 230 in the first direction X of the battery cell 10 can also cover the second connection area 2112 and the first connection area 2111.

[0072] Optionally, the first connection region 2111 of the first tab group 201 is located at an end of the second segment 212 away from the first segment 211, or the first connection region 2111 of the first tab group 201 is located in the middle region of the second segment 212; the second connection region 2112 of the second tab group 202 is located at an end of the second segment 212 away from the first segment 211, or the second connection region 2112 of the second tab group 202 is located in the middle region of the second segment 212. The above is merely an exemplary introduction. The embodiment of the present application does not limit the position of the electrical connection between the second segment 212 of the first tab group 201 and the second segment 212 of the second tab group 202, and the specific position can be selected according to actual needs.

[0073] Referring again to Figure 5 , the connection between the second segment 212 of the tab 210 and the first segment 211 defines a first boundary 2101, and the end of the second segment 212 away from the first segment 211 defines a second boundary 2102. The first boundary 2101 of each tab 210 is where the tab 210 bends. In a direction away from the main body 100, the second segment 212 of the first tab group 201 has a first inner surface facing the main body 100 and a first outer surface facing away from the main body 100. The second segment 212 of the second tab group 202 is stacked and connected to the first outer surface. Furthermore, the second segments 212 of each tab 210 of the first tab group 201 are stacked and connected, and the second segments 212 of each tab 210 of the second tab group 202 are also stacked and connected.

[0074] As shown in FIG5 , in the second direction Y of the battery cell 10 , the second boundaries 2102 of all the tabs 210 of the first tab group 201 are spaced apart from the first boundaries 2101 of the tabs 210 of the second tab group 202 by a spacing of L1. The length of the main body 100 in the second direction Y of the battery cell 10 is A, and L1 satisfies the following: 0.1 mm ≤ L1 ≤ A / 2. This ensures an appropriate spacing between the second boundaries 2102 of the first tab group 201 and the bend of the second tab group 202, preventing the second segments 212 of the first tab group 201 from squeezing the tabs 210 of the second tab group 202 in the event of an abnormality such as a drop or squeezing. When L1 is less than 0.1 mm, the ends of the second segments of the tabs of the first tab group may protrude excessively, causing the first tab group to contact other structures outside the battery cell. When L1 is greater than A / 2, the weld area between the second segments of the two tab groups is small, affecting weld strength.

[0075] In the second direction Y of the battery cell 10, the second boundaries 2102 of all the tabs 210 of the second tab group 202 are spaced apart from the first boundaries 2101 of the tabs 210 of the first tab group 201, and the spacing is L2. L2 satisfies the following: 0.1mm≤L2≤A / 2. This ensures that the second segments 212 of the tabs 210 of the second tab group 202 are of appropriate length, preventing the second segments 212 of the tabs 210 of the second tab group 202 from contacting other structures such as the battery packaging bag in the event of an abnormality such as falling or squeezing, and preventing the tabs 210 of the second tab group 202 from being squeezed, deformed, or broken. When L2 is less than 0.1mm, the ends of the second segments of the tabs of the second tab group may protrude too much, causing the second tab group to contact other structures outside the battery cell. When L2 is greater than A / 2, the welding area of ​​the second segments of the two tab groups is small, affecting the welding strength.

[0076] In addition, L1 satisfies the following conditions: 0.1 mm ≤ L1 ≤ A / 2, and L2 satisfies the following conditions: 0.1 mm ≤ L2 ≤ A / 2. This also facilitates ensuring that the second segment 212 of the first tab group 201 and the second segment 212 of the second tab group 202 have an appropriate area for stacking and connecting, and provides good connection stability. Furthermore, the first connection region 2111 and the second connection region 2112 have the same size in the second direction Y of the battery cell 10, and are C, where C satisfies the following conditions: 2 mm ≤ C ≤ A / 2.

[0077] In the embodiment of the present application, the second boundary 2102 of the second segment 212 of the tab 210 of the first tab group 201 is set to be flush or nearly flush, and the second boundary 2102 of the second segment 212 of the tab 210 of the second tab group 202 is set to be flush or nearly flush, to prevent the end of some tabs 210 from protruding and colliding with other structures. Optionally, in the second direction Y of the battery cell 10, the spacing between the second boundaries 2102 of two adjacent tabs 210 of the first tab group 201 is x1, and x1 satisfies: 0mm≤x1≤0.5mm. In the second direction Y of the battery cell 10, the spacing between the second boundaries 2102 of two adjacent tabs 210 of the second tab group 202 is x2, and x2 satisfies: 0mm≤x2≤0.5mm.

[0078] The battery cell 10 of the present embodiment includes two types of tab structures 200 with opposite polarities, one type of tab structure 200 being a positive tab structure 410 and the other type of tab structure 200 being a negative tab structure 420. There is at least one positive tab structure 410 and at least one negative tab structure 420. Multiple sets of tab structures 200, located on the same side of the main body 100, are arranged side by side and spaced apart in the third direction Z of the battery cell 10.

[0079] In the first direction X of the battery cell 10, the positive electrode tab structure 410 and the negative electrode tab structure 420 can be arranged on the same side of the main body 100; alternatively, the positive electrode tab structure 410 is arranged on one side of the main body 100, and the negative electrode tab structure 420 is arranged on the other side of the main body 100. Optionally, when there are multiple positive electrode tab structures 410 and multiple negative electrode tab structures 420, the multiple positive electrode tab structures 410 and the multiple negative electrode tab structures 420 can all be arranged on the same side of the main body 100 and arranged side by side and spaced apart along the third direction Z of the battery cell 10.

[0080] The present application also provides a battery comprising a housing and the battery cell 10 described above, wherein the housing has a receiving space, and the battery cell 10 is received in the receiving space of the housing. The battery also comprises an electrolyte, which fills the receiving space of the housing and infiltrates the battery cell.

[0081] The outer shell also has an electrode opening connected to the accommodating space. The battery may also include an electrode lead and a pole. One end of the electrode lead is electrically connected to one of the tab structures 200 and the other end is connected to the pole. The pole is arranged in the electrode opening and fixed to the outer shell. The pole at least partially extends out of the outer shell and is used to be electrically connected to an external circuit.

[0082] The embodiments of the present application do not limit the types of the housing, electrode leads, poles, electrolyte, pole piece 240 and isolation membrane 220. All the above-mentioned materials suitable for batteries in this field are applicable to the present application, and the specific selection can be made according to actual needs.

[0083] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. This is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0084] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: The battery cell comprises a battery cell body, and the battery cell body comprises: the main body; and A tab structure, the tab structure comprising a plurality of tabs arranged on the same side of the main body along a first direction of the battery cell, each of the tabs being connected to the main body; Among them, a part of the pole lugs form a first pole lug group, and another part of the pole lugs form a second pole lug group; at least part of the pole lugs of the first pole lug group and at least part of the pole lugs of the second pole lug group are respectively extended from the main body in directions away from each other, and all the pole lugs of the first pole lug group are bent toward each other at the first bending area and all the pole lugs of the second pole lug group are bent toward each other at the second bending area and connected in a stacked manner, and the first bending area and the second bending area are spaced apart in a second direction perpendicular to the first direction.

2. The battery cell according to claim 1, characterized in that: The tab includes a first section connected to the main body and a second section connected to the first section; One of the pole lugs of the first pole lug group is a first pole lug, a connection between the first section and the second section of the first pole lug is located in the first bending region, and the other pole lugs of the first pole lug group extend to the first bending region and then bend toward the second pole lug group; One of the pole lugs of the second pole lug group is the second pole lug, at least one pole lug is provided between the second pole lug and the first pole lug, the connection between the first section and the second section of the second pole lug is located in the second bending area, the other pole lugs of the second pole lug group extend to the connection between the first section and the second section of the second pole lug and then bend toward the first pole lug group; the second section of the first pole lug group and the second section of the second pole lug group are stacked and connected in the first direction of the battery cell.

3. The battery cell according to claim 2, characterized in that: Two adjacent pole tabs of the pole tab structure at least partially overlap in the second direction of the battery core; Along the second direction of the battery cell, the pole ear structure includes a middle pole ear, the middle pole ear and a plurality of pole ears located on one side of the middle pole ear in the second direction form the first pole ear group, and the plurality of pole ears located on the other side of the middle pole ear in the second direction form the second pole ear group.

4. The battery cell according to claim 3, characterized in that: In the second direction of the battery cell, the pole ear of the first pole ear group farthest from the middle pole ear forms the first pole ear; and / or, In the second direction of the battery cell, the pole ear of the second pole ear group farthest from the middle pole ear forms the second pole ear.

5. The battery cell according to claim 2, characterized in that: In the first direction, the second section of the second tab group is stacked and connected with the second section of the first tab group at a side away from the main body; or, All the second sections of the second tab group are inserted between the second sections of two adjacent tabs of the first tab group; or, All the second sections of the first tab group are inserted between the second sections of two adjacent tabs of the second tab group; or, The second section of the first pole tab group is inserted between the second sections of two adjacent pole tabs of the second pole tab group.

6. The battery cell according to claim 2, characterized in that: The length of the main body in the second direction of the battery core is A; the connection between the second section of the tab and the first section has a first boundary, and the end of the second section away from the first section has a second boundary; In the second direction, the second boundaries of all the pole tabs of the first pole tab group are spaced from the first boundaries of the pole tabs of the second pole tab group, and the spacing is L1, and L1 satisfies: 0.1 mm≤L1≤A / 2; In the second direction, the second boundaries of all the pole tabs of the second pole tab group are spaced apart from the first boundaries of the pole tabs of the first pole tab group, and the spacing is L2, and L2 satisfies: 0.1 mm≤L2≤A / 2.

7. The battery cell according to claim 6, characterized in that: In the second direction, the distance between the second boundaries of two adjacent tabs of the first tab group is x1, and x1 satisfies: 0mm≤x1≤0.5mm; and / or, In the second direction, a distance between the second boundaries of two adjacent pole tabs of the second pole tab group is x2, and x2 satisfies: 0 mm ≤ x2 ≤ 0.5 mm.

8. The battery cell according to claim 2, characterized in that: The second segment of the first pole tab group has a first connection area, and the second segment of the second pole tab group has a second connection area, and the second connection area is stacked with the first connection area in the first direction of the battery cell; the battery cell also includes a solder layer, and the solder layer covers the first connection area and the second connection area to electrically connect the first pole tab group and the second pole tab group.

9. The battery cell according to claim 3, characterized in that: The pole lug has an inner surface, and the pole lug is bent toward a side where the inner surface is located; the inner surface of the pole lug includes a first surface, a portion of the surface of the first section forms the first surface, and the first surface is connected to the main body; An angle β is formed between the first surface of the middle electrode and the second direction of the battery cell, and β satisfies: 5°≤β≤45°.

10. The battery cell according to claim 9, characterized in that: The inner surface of the pole lug includes a second surface, and a portion of the surface of the second section forms the second surface; the inner surface of a portion of the pole lug of the pole lug structure also includes a connecting transition surface connected between the first surface and the second surface; The connecting transition surface is a curved surface; or, At least part of the connection transition surface is planar, and an angle α is formed between the planar part of the connection transition surface of the middle pole tab and the second surface, and α satisfies: 90°≤α≤150°.

11. The battery cell according to claim 1, characterized in that: The number of the electrode tabs in the first electrode tab group is n1, and the number of the electrode tabs in the second electrode tab group is n2, wherein n1:n2=1:(1-5).

12. The battery cell according to claim 11, characterized in that: n1 and n2 satisfy: n1:n2=1:(1~1.2).

13. The battery cell according to claim 1, characterized in that: The battery cell includes two groups of tab structures, one group of tab structures is a positive tab structure, and the other group of tab structures is a negative tab structure; the positive tab structure and the negative tab structure are arranged on the same side of the main body.

14. A battery, characterized in that: include: shell; and, The battery cell according to any one of claims 1 to 13, wherein the battery cell is arranged in the inner space of the shell.

Images