Battery Cells and Battery Packs

Abstract

The present invention relates to the field of battery technology, and in particular to a battery cell and a battery pack. The battery cell includes: a cover plate assembly including a cover plate body and a pole arranged on the cover plate body; a plurality of protruding single-piece pole ears are formed on the side of the pole group and are arranged at intervals along the thickness direction of the pole group, and the plurality of single-piece pole ears are gathered in a direction close to each other to form a pole ear, and the end of the pole ear close to the pole group is formed as a gathering part, and the single-piece pole ears of the gathering part are arranged at intervals; the end of the pole ear away from the pole group is formed as a mounting part, and the single-piece pole ears of the mounting part are fitted with each other; the mounting part and the pole column not connected to the cover plate body are welded to form a weld mark, and then the pole ear is bent so that the gathering part and the weld mark are arranged at an angle. The present invention can effectively shorten the length of the pole ear, reduce costs, facilitate processing, and at the same time reduce the space for folding the pole ear, thereby saving space inside the battery cell, which can be used to increase the capacity of the battery cell.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell and a battery pack. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, power batteries are widely used as new types of batteries in electric vehicles and energy storage fields, and the performance and safety requirements of power batteries are increasing.

[0003] Lithium-ion power batteries generally include an internal battery structure and an external battery structure. The internal battery structure mainly includes a battery cell pole group, and the external battery structure mainly includes a battery cell cover and a battery cell shell. The battery cell shell provides a space for accommodating the battery cell pole group, and the battery cell cover and the battery cell shell are welded together to fix the pole group in the internal space.

[0004] In the current traditional battery structure, such as Figures 1 to 3 As shown, the pole group pole ear 2 is first welded to the connecting piece 1 to form the first welding area 4, and then the connecting piece 1 is welded to the pole column on the cover plate 3 to form the second welding area 5. After the pole ear 2 is welded to the connecting piece, the pole group needs to be kept flat on both sides of the cover plate 3, and the core is closed after the cover plate 3 is connected to the connecting piece 1, so as to facilitate the assembly of the connecting piece 1 and the cover plate 3. In order to avoid interference between the pole group and the cover plate 3, the pole group pole ear 2 needs to be designed to be longer, which is difficult to process and wastes material costs. After the pole group core is put into the shell, the space for folding the pole ear needs to reserve a certain distance according to the length of the pole group pole ear 2 to prevent the pole group pole ear 2 from being inserted upside down or inverted, and to prevent the pole group pole ear 2 from being torn or short-circuited. However, the longer the pole group pole ear 2 is designed, the larger the reserved spacing is required. The increase in the reserved spacing will sacrifice the internal space of the battery cell, thereby affecting the battery cell capacity. In addition, the installation position of the electrode group tab 2 should be careful not to block the injection port 302 and the exhaust port 301 opened on the cover plate 3, so as to meet the injection and vacuum requirements in the battery cell production process and ensure that the gas inside the battery cell can be discharged in time when the battery cell loses control. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a battery cell and a battery pack to solve the problem that the pole ears in the existing battery cells provided with connecting plates are long, difficult to process, waste materials, and a large space is reserved for the folded pole ears, which occupies the space inside the battery cell and affects the capacity of the battery cell.

[0006] A first aspect of the present invention provides a battery cell, wherein the battery cell comprises:

[0007] A cover plate assembly, comprising a cover plate body and a pole arranged on the cover plate body;

[0008] A pole group, wherein a plurality of protruding single-piece pole ears are formed on its side and are spaced apart along the thickness direction of the pole group, wherein the plurality of single-piece pole ears are gathered in a direction close to each other to form a pole ear, wherein one end of the pole ear close to the pole group is formed as a gathering portion, wherein the single-piece pole ears of the gathering portion are spaced apart from each other; and one end of the pole ear away from the pole group is formed as a mounting portion, wherein the single-piece pole ears of the mounting portion are fitted together;

[0009] The mounting portion is welded to the pole that is not connected to the cover plate body to form a weld mark, and then the pole ear is bent so that the folded portion and the weld mark are arranged at an angle.

[0010] Preferably, a boss portion protruding outward is formed on the side wall of the pole, and the mounting portion is arranged on a side of the boss portion facing the interior of the battery cell.

[0011] Preferably, the outer wall of the pole is formed with a flange portion protruding along the axial direction of the pole, and the flange portion is bent to change the protruding direction so as to be folded outward, so that the pole is riveted and fixed.

[0012] Preferably, after the flange portion is bent, a dimension of the flange portion in the first direction is f, where f≥1 mm, and a thickness dimension of the flange portion in the second direction is g, where g≥0.5 mm.

[0013] Preferably, 1 mm ≤ f / g ≤ 3 mm.

[0014] Preferably, the thickness dimension of the boss portion in the second direction is t, and t≥0.5 mm.

[0015] Preferably, a mounting hole is provided on the cover plate body, and the pole is arranged in the mounting hole;

[0016] After the flange portion is bent, a distance between an end of the flange portion away from the pole body and a hole wall of the mounting hole in the first direction is k, and k≥0.5 mm.

[0017] Preferably, the cover plate assembly further comprises:

[0018] A first insulating member is sandwiched between the flange portion and the cover plate body in the second direction, and a thickness dimension of the first insulating member in the second direction is c, c ≥ 0.5 mm, and / or 0.3 mm ≤ c ≤ 2 mm;

[0019] And / or, a thickness dimension of a portion of the cover plate body abutting against the first insulating member in the second direction is h, and h≥0.5 mm.

[0020] Preferably, there are two pole groups, and in the first direction, the pole ears on the two pole groups are symmetrically arranged on both sides of the pole column, and the distance between the ends of the two weld marks facing each other in the first direction is Z;

[0021] The mounting portion is disposed in the middle of the electrode group in the thickness direction, and in the thickness direction of the electrode group, a distance between one end of the electrode group in the thickness direction and the mounting portion is p, 2×p≥(Z+1) mm.

[0022] A second aspect of the present invention provides a battery pack, comprising the battery cell described in any of the above technical solutions.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In the battery cell of the present invention, the pole ear on the pole group includes a folding portion and an installation portion, and the installation portion is welded to the pole column that has not yet been connected to the cover plate body to form a weld mark, so that the length of the pole ear can be shortened, the cost can be reduced, and the processing is convenient. At the same time, the space for folding the pole ear is reduced, so that the space inside the battery cell is saved, which can be used to increase the capacity of the battery cell, so that the capacity of the battery pack meets the user's high endurance demand for electric vehicles; in addition, the pole ear is first welded to the pole column and then the pole column and the cover plate body are assembled, so that the setting position of the pole ear can avoid the injection port and the exhaust port on the cover plate body, and the injection port and the exhaust port are unobstructed, which is convenient for the operation of vacuuming and injecting liquid inside the battery cell in the battery cell production process, and at the same time ensures that when the battery cell is out of control, the internal gas can be discharged from the exhaust port in time, thereby ensuring the safety of the battery cell and improving the safety of the battery pack.

[0025] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a structural schematic diagram of welding the pole lug and the connecting piece of the electrode group in the prior art;

[0028] Figure 2 It is a structural schematic diagram of the electrode group tab and the cover plate being welded to the connecting piece respectively in the prior art;

[0029] Figure 3It is a schematic diagram of the structure in which the pole lug and the cover plate of the electrode group are respectively welded to the connecting piece in another viewing angle in the prior art;

[0030] Figure 4 for Figure 3 Schematic diagram of the enlarged structure at D in the middle;

[0031] Figure 5 A schematic diagram of the assembly structure of the electrode group and the electrode column in the battery cell before the battery cell is assembled according to an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of the assembly structure of the electrode group and the electrode column in the battery cell provided by an embodiment of the present invention before the battery cell is assembled from another perspective;

[0033] Figure 7 for Figure 6 Schematic diagram of the enlarged structure at E in the middle;

[0034] Figure 8 A schematic diagram of the assembly structure of the electrode group and the electrode column in the battery cell after the battery cell is assembled according to an embodiment of the present invention;

[0035] Fig. 9 A schematic diagram of the exploded structure of a battery cell provided in an embodiment of the present invention;

[0036] Fig.10 A schematic diagram of the assembly structure of the cover plate assembly and the electrode group in the battery cell provided by an embodiment of the present invention;

[0037] Fig.11 For along Fig.10 The cross-section taken at AA in the middle;

[0038] Fig.12 for Fig.11 Schematic diagram of the enlarged structure at C in the middle;

[0039] Fig.13 A schematic diagram of the structure of a flanged portion on a pole in a battery cell provided by an embodiment of the present invention before being bent;

[0040] Fig.14 A schematic diagram of the structure of a flange portion on a pole in a battery cell during a bending process provided by an embodiment of the present invention;

[0041] Fig.15 A schematic diagram of the structure of the flanged portion on the pole in the battery cell after being bent provided by an embodiment of the present invention;

[0042] Fig.16 This is a schematic diagram of the structure of the assembled battery cell provided by an embodiment of the present invention.

[0043] Icons: 10-pole group; 11-pole ear; 111-single-piece pole ear; 101-folding portion; 102-installing portion; 1021-weld mark; 20-cover assembly; 21-cover body; 211-installing hole; 22-pole; 221-boss portion; 222-flanged portion; 23-seal; 241-first insulating member; 242-second insulating member; 30-housing; D1-first direction; D2-second direction; 1-connecting piece; 2-pole group pole ear; 3-cover; 301-exhaust port; 302-liquid injection port; 4-first welding area; 5-second welding area. DETAILED DESCRIPTION

[0044] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0045] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0046] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0047] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0048] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0049] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0050] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0051] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0052] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0053] According to a first aspect of the present invention, a battery cell is provided, which specifically includes a pole group 10 and a cap plate assembly 20 .

[0054] Hereinafter, a specific structure of the battery cell according to this embodiment will be described.

[0055] In this embodiment, if Fig. 9 and Fig.10 As shown, the cover assembly 20 includes a cover body 21 and a pole 22 arranged on the cover body 21. The cover body 21 can form a plate-like structure in a rectangular or circular shape. The cover body 21 is provided with a through hole penetrating the body for installing the pole 22.

[0056] It should be noted that, in this embodiment, the pole 22 and the cover plate body 21 are assembled after the pole group 10 is assembled.

[0057] In this embodiment, if Figures 5 to 7 As shown, the electrode group 10 is formed by winding a electrode sheet or by stacking a plurality of electrode sheets, a plurality of protruding single-piece pole ears 111 are formed on the side of the electrode group 10, and the plurality of single-piece pole ears 111 are arranged at intervals along the thickness direction of the electrode group 10, and the plurality of single-piece pole ears 111 are gathered and compacted in a direction close to each other, so that they are at least partially stacked together to form the electrode ear 11, and one end of the electrode ear 11 close to the main body of the electrode group 10 is formed as a gathering portion 101, and the single-piece pole ears 111 located in the gathering portion 101 are arranged at intervals from each other, that is, there is a gap between the single-piece pole ears 111 located in the gathering portion 101; one end of the electrode ear 11 away from the electrode group 10 is formed as a mounting portion 102, and the single-piece pole ears 111 located in the mounting portion 102 are in contact with each other.

[0058] like Figures 6 to 8 As shown, before the electrode group 10 is assembled, the mounting portion 102 and the pole 22 that has not yet been connected to the cover body 21 are welded to form a weld mark 1021. Specifically, the mounting portion 102 is welded to the side of the pole 22 facing the inside of the battery cell to form a weld mark 1021, and then the pole ear 11 is bent to assemble the electrode group 10 so that the folding portion 101 and the weld mark 1021 are set at an angle, thereby completing the assembly of the electrode group 10 before the pole 22 and the cover body 21 are assembled. This effectively shortens the length of the pole ear 11, reduces costs, and facilitates processing. At the same time, the space H of the folded pole ear 11 is reduced, thereby saving space inside the battery cell, which can be used to increase the capacity of the battery cell.

[0059] Preferably, in this embodiment, the mounting portion 102 is disposed in the middle of the electrode group 10 in the thickness direction, so that the length of the electrode tab 11 can be the shortest.

[0060] In addition, this application is relative to Figures 1 to 3The structure shown omits the connecting sheet 1, and instead first welds the pole ear 11 to the pole column 22 and then assembles the pole column 22 with the cover body 21, so that the pole ear 11 can be directly arranged below the pole column 22, ensuring that the setting position of the pole ear 11 can effectively avoid the injection port and the exhaust port on the cover body 21, and even when the cover body 21 is small in size, the pole ear 11 will not block the injection port and the exhaust port, thereby facilitating the vacuuming and liquid injection operations inside the battery cell during the battery cell production process, and at the same time ensuring that when the battery cell is out of control, the internal gas can be discharged from the exhaust port in time to ensure the safety of the battery cell.

[0061] It should be noted that the lengths of all the single-piece pole tabs 111 on the pole group 10 are the same. In order to facilitate welding of the pole tabs 11 , the single-piece pole tabs 111 are gathered and compacted so as to be stacked together.

[0062] Compared with this application Figure 7 and the prior art Figure 4 The structure, such as Figure 7 As shown, the dimension of the electrode group 10 in the thickness direction is T; in the thickness direction of the electrode group 10, the distance between one end of the electrode group 10 in the thickness direction and the mounting portion 102 is P. It should be noted that, since the pole 22 is first connected to the electrode group 10 in the present application, and the pole 22 is connected to the cover plate body 21 after the electrode group 10 is cored, the mounting portion 102 can be set in the middle position in the thickness direction of the electrode group 10, thereby reducing the length of the pole ear 11, so that the distance from both ends of the electrode group 10 in the thickness direction to the mounting portion 102 is P; the length of the retracted portion 101 on the outermost single-piece pole ear 111 in the thickness direction of the electrode group 10 The dimension is a. It should be noted that, as described above, since the mounting portion 102 is located in the middle position in the thickness direction of the electrode group 10, the length dimension of the gathered portion 101 on the outermost single-piece pole ears 111 at both ends in the thickness direction of the electrode group 10 is a, and the length dimension of the mounting portion 102 is b. The shortest dimension of b needs to ensure the setting area range of the weld stamp 1021. The length dimension of the single-piece pole ear 111 is a+b. In the height direction of the electrode group 10, the dimension of the gathered portion 101 is e; when P>T / 2, the dimension a of the outermost single-piece pole ear 111 in the thickness direction of the electrode group 10 is the longest, and the dimension b is the shortest, a= Therefore, the sizes of P and e will affect the length of the single-piece electrode tab 111, thereby affecting the length of the electrode tab 11.

[0063] like Figure 4 As shown, the position marked a1 corresponds to the position marked a in this application, the position marked b1 corresponds to the position marked b in this application, and the position marked P1 corresponds to the position marked P in this application. Figure 4The portion corresponding to the mounting portion 102 of the present application (i.e., the size P1) is obviously eccentrically arranged relative to the thickness of the electrode group 10. This is because in the prior art, the flat electrode group tab 2 needs to be welded to the connecting piece 1 first, and then the connecting piece 1 needs to be welded to the pole 22 already installed on the cover plate 3, and finally the electrode group core is assembled. Therefore, the distance G1 between the electrode group and the cover plate 3 needs to be considered, so that Figure 4 The dimension marked as e1 is larger than the dimension e of the folding portion 101 of the present application, thereby increasing the size of the pole ear 11, and also increasing the space required for folding the pole ear 11. In the present application, since the pole 22 has not been assembled with the cover body 21 when the pole ear 11 is bent, the mounting portion 102 can be set in the middle of the thickness direction of the pole group 10, and assembled with other components in the cover assembly 20 after the pole ear 11 is bent. In this way, there is no need to consider the distance between the pole group 10 and the cover body 21 when welding the pole ear 11, thereby effectively shortening the length of the pole ear 11, reducing costs, facilitating processing, and reducing the space H of the folded pole ear 11, thereby saving space inside the battery cell, which can be used to increase the capacity of the battery cell.

[0064] It should be noted that Figures 1 to 16 The unit of marked dimensions is mm.

[0065] Furthermore, in this embodiment, if Figures 6 to 15 As shown, the side wall of the pole 22 is formed with a boss portion 221 protruding outward, and the mounting portion 102 is arranged on the side of the boss portion 221 facing the inside of the battery cell, so as to facilitate the connection between the pole lug 11 and the pole 22. Preferably, the boss portion 221 is formed as a plate-like structure arranged perpendicular to the second direction D2, and the boss portion 221 is arranged on the side of the cover body 21 facing the inside of the battery cell.

[0066] Furthermore, in this embodiment, if Figures 11 to 15 As shown, before the pole 22 is assembled with the cover body 21, the outer wall of the pole 22 is formed with a flange portion 222 protruding along the axial direction of the pole 22, and the flange portion 222 is bent to change the protruding direction so that it is folded outward along the radial direction of the pole 22, so that the pole 22 is riveted and fixed relative to the cover body 21. The flange portion 222 is preferably formed into a closed annular structure to ensure that the pole 22 is firmly and reliably riveted and fixed.

[0067] In a preferred embodiment, Fig.12 As shown, after the flange portion 222 is bent, the dimension of the flange portion 222 in the first direction D1 is f, f≥1mm, and the thickness dimension of the flange portion 222 in the second direction D2 is g, g≥0.5mm, so as to ensure that the flange portion 222 has sufficient structural strength and ensure that the pole 22 is riveted and fixed firmly and reliably.

[0068] Furthermore, preferably, 1 mm ≤ f / g ≤ 3 mm, so that the flanging portion 222 can be easily bent while ensuring the structural strength of the flanging portion 222 , thereby improving the assembly efficiency of the battery cell.

[0069] In this embodiment, if Figures 9 to 12 As shown, the cover assembly 20 also includes a seal 23. The seal 23 can be an annular and elastic sealing ring to play an insulating and sealing role. The seal 23 can be formed into a stepped structure, so that the seal 23 is arranged between the pole 22 and the cover body 21 in the first direction D1; the seal 23 is clamped between the boss portion 221 and the cover body 21 in the second direction D2.

[0070] In this embodiment, if Fig.12 As shown, the thickness dimension of the boss portion 221 in the second direction D2 is t, t≥0.5mm, so as to prevent the boss portion 221 from deforming, causing the seal 23 to be compressed and loosened to cause sealing leakage. Figures 1 to 4 In the traditional solution shown, since the pole 22 needs to be connected to the cover plate first and then welded to the connecting plate 1, the thickness of the bottom plate of the pole 22 is usually ≥1.3 mm to avoid the high temperature of welding burning the sealing ring and causing sealing failure. Therefore, the boss portion 221 of the present application can be designed to be thinner than the bottom plate of the pole 22 in the traditional solution, thereby further reducing the occupancy of the internal space of the battery cell, thereby increasing the battery cell capacity.

[0071] In this embodiment, a mounting hole 211 is opened on the cover body 21, and the pole 22 is arranged in the mounting hole 211; Fig.12 As shown, after the flange portion 222 is bent, the distance between the end of the flange portion 222 away from the pole 22 body and the hole wall of the mounting hole 211 in the first direction D1 is k, k≥0.5mm, thereby improving the reliability of riveting using the flange portion 222.

[0072] In this embodiment, if Figures 5 to 12 As shown, two pole groups 10 are provided. In the first direction D1, the pole ears 11 on the two pole groups 10 are symmetrically arranged on both sides of the pole column 22, and the distance between the ends of the two weld marks 1021 facing each other in the first direction D1 is Z; in the thickness direction of the pole group 10, the distance between the pole group 10 and the mounting portion 102 is P, 2×P≥(Z+1) mm, so as to ensure that the pole ears 11 can be bent smoothly and that the two pole groups 10 can be fitted after the pole ears 11 are bent to achieve core closing.

[0073] In this embodiment, if Figures 9 to 12As shown, the cover assembly 20 also includes a first insulating member 241 and a second insulating member 242, wherein the first insulating member 241 is clamped between the flange portion 222 and the cover body 21 in the second direction D2, and the thickness dimension of the first insulating member 241 in the second direction D2 is c, c≥0.5g, thereby ensuring that the first insulating member 241 has sufficient supporting strength for the flange portion 222 after the flange portion 222 is bent; preferably, 0.3mm≤c≤2mm, thereby ensuring the insulation effect and avoiding the excessive size of c that causes a large creep deformation and causes sealing failure.

[0074] The thickness dimension of the portion where the cover body 21 abuts against the first insulating member 241 in the second direction D2 is h, and h≥0.5mm, so as to ensure that the cover body 21 has sufficient support strength for the flange portion 222 after the flange portion 222 is bent. The second insulating member 242 is arranged on the side of the cover body 21 facing the inside of the battery cell, and the first insulating member 241 and the second insulating member 242 can both be made of insulating plastic materials to form insulation protection for the cover body 21 to avoid short circuit.

[0075] In addition, in this embodiment, if Fig.16 As shown, the battery cell also includes a shell 30, and a space is formed inside the shell 30 for accommodating the electrode group 10 after the electrode group 10 is assembled. After the electrode group 10 is assembled, the second insulating member 242, the sealing member 23, the cover body 21, and the first insulating member 241 are sequentially inserted into the pole 22 to complete the assembly of the cover assembly 20, thereby realizing the assembly of the cover assembly 20 and the electrode group 10, and then the assembled electrode group 10 is installed in the shell 30, and finally the cover body 21 and the shell 30 are welded to close the shell 30.

[0076] It should be noted that in this embodiment, the first direction D1 is perpendicular to the second direction D2. For example, when the cover body 21 is formed into a rectangular sheet structure, the first direction D1 can be the width direction of the cover body 21, and the second direction D2 can be the thickness direction of the cover body 21.

[0077] In order to verify whether the cell structure of the present invention has good fixing and sealing effects after assembly, the following pole force test and insulation withstand voltage test are carried out on cells with different parameters of c, f, g, t, k and h. The test results are shown in the following table:

[0078]

[0079] The failure mode " / " in the table indicates that the battery cell has no abnormal failure. Referring to the parameters in the above table, it can be seen that in Examples 1 to 8, the parameters of c, f, g, t, k and h are all within the specified range, and the pole force test and insulation withstand voltage test test results are all qualified. Different failure situations occurred in Comparative Examples 1 to 7. Specifically, the insulation failure in Comparative Example 1 was mainly caused by the small size of c; the insulation failure in Comparative Example 2 was mainly caused by c being less than 0.5g; the helium leakage failure in Comparative Example 3 was mainly caused by the small size of f; the helium leakage failure in Comparative Example 4 was mainly caused by the small size of g; the helium leakage failure in Comparative Example 5 was mainly caused by the small size of t; the helium leakage failure in Comparative Example 6 was mainly caused by the small size of k; the helium leakage failure in Comparative Example 7 was mainly caused by the small size of h.

[0080] According to a battery cell provided by the present invention, the pole ear on the pole group includes a folding portion and an installation portion, and the installation portion is welded to the pole column that has not yet been connected to the cover plate body to form a weld mark, thereby shortening the length of the pole ear, reducing the cost, and facilitating processing, while reducing the folding space of the pole ear, thereby saving space inside the battery cell, which can be used to increase the capacity of the battery cell; in addition, the pole ear is first welded to the pole column and then the pole column and the cover plate body are assembled, so that the setting position of the pole ear can avoid the injection port and the exhaust port on the cover plate body, and the injection port and the exhaust port are unobstructed, which facilitates the operation of vacuuming and injecting liquid inside the battery cell in the battery cell production process, and at the same time ensures that when the battery cell is out of control, the internal gas can be discharged from the exhaust port in time to ensure the safety of the battery cell.

[0081] A battery pack provided according to the present invention includes the battery cell as described above, wherein at least one battery cell is provided. When a plurality of battery cells are provided, at least some of the battery cells are connected in series and / or in parallel, the safety of the battery pack is effectively improved, and the capacity of the battery pack meets the user's high endurance requirements for electric vehicles.

[0082] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: A cover plate assembly, comprising a cover plate body and a pole arranged on the cover plate body; A pole group, a plurality of protruding single-piece pole ears are formed on its side and are arranged at intervals along the thickness direction of the pole group, and the plurality of single-piece pole ears are gathered in a direction close to each other to form a pole ear, and one end of the pole ear close to the pole group is formed as a gathering part, and the single-piece pole ears of the gathering part are arranged at intervals; one end of the pole ear away from the pole group is formed as a mounting part, and the single-piece pole ears of the mounting part are attached to each other; two pole groups are provided, and the mounting part on each pole group is arranged in the middle of the thickness direction of the pole group; The mounting portion is welded to the pole that is not connected to the cover plate body to form a weld mark, and then the pole ear is bent so that the folded portion and the weld mark are arranged at an angle, so that the two bent pole groups are attached to achieve core closure, and after the core closure, the pole is connected to the cover plate body; In the first direction, the pole ears on the two pole groups are symmetrically arranged on both sides of the pole, and the distance between the ends of the two weld marks facing away from each other in the first direction is Z; In the thickness direction of the electrode group, a distance between one end of the electrode group in the thickness direction and the mounting portion is p, and 2×p≥(Z+1) mm.

2. The battery cell according to claim 1, characterized in that: The side wall of the pole is formed with a boss portion protruding outward, and the mounting portion is arranged on a side of the boss portion facing the inside of the battery cell.

3. The battery cell according to claim 2, characterized in that: The outer wall of the pole is formed with a flange portion protruding along the axial direction of the pole, and the flange portion is bent to change the protruding direction so as to be folded outward, so that the pole is riveted and fixed.

4. The battery cell according to claim 3, characterized in that: After the flange portion is bent, a dimension of the flange portion in the first direction is f, where f≥1 mm, and a thickness dimension of the flange portion in the second direction is g, where g≥0.5 mm.

5. The battery cell according to claim 4, characterized in that: 1mm≤f / g≤3mm.

6. The battery cell according to claim 2, characterized in that: The thickness dimension of the boss portion in the second direction is t, and t≥0.5 mm.

7. The battery cell according to claim 3, characterized in that: The cover plate body is provided with a mounting hole, and the pole is arranged in the mounting hole; After the flange portion is bent, a distance between an end of the flange portion away from the pole body and a hole wall of the mounting hole in the first direction is k, and k≥0.5 mm.

8. The battery cell according to claim 4, characterized in that: The cover plate assembly also includes: A first insulating member is sandwiched between the flange portion and the cover plate body in the second direction, and a thickness dimension of the first insulating member in the second direction is c, c ≥ 0.5 mm, and / or 0.3 mm ≤ c ≤ 2 mm; And / or, a thickness dimension of a portion of the cover plate body abutting against the first insulating member in the second direction is h, and h≥0.5 mm.

9. A battery pack, characterized in that: A battery cell comprising the battery cell described in any one of claims 1 to 8.

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