Battery

Abstract

Battery, comprising: two single cells (100), each of the single cells (100) having a first positive tab piece (110), a second positive tab piece (120), a first negative tab piece (130) and a second negative tab piece (140) which are spaced apart from one another, the terminal ends of the first positive tab piece (110) and the first negative tab piece (130) being arranged with an electrode near the outer edge of the single cell (100) and the terminal ends of the second positive tab piece (120) and the second negative tab piece (140) being arranged with the electrode near the center of the single cell (100); a cover plate assembly (200) provided with a positive welding surface (210) and a negative welding surface (220); wherein the first positive tab piece (110) and the second positive tab piece (120) of each of the individual cells (100) are welded to the positive welding surface (210) to form two spaced positive welding marks (101), and the first negative tab piece (130) and the second negative tab piece (140) of each of the individual cells (100) are welded to the negative welding surface (220) to form two spaced negative welding marks (102).

Description

FIELD OF TECHNOLOGY

[0001] The present utility model relates to the technical field of batteries, in particular a battery. BACKGROUND

[0002] With the continuous improvement of the energy density of lithium-ion batteries and the accelerated development of battery pack systems, the requirements for fast-charging capability of batteries are becoming increasingly stringent. At the same time, the internal overcurrent capacity of the battery must also be improved. However, with the higher overcurrent requirements, the number of layers of battery tabs also increases. For the production process, this undoubtedly means increased manufacturing complexity and reduced manufacturing efficiency.

[0003] Therefore, an urgent technical challenge is to ensure the operational suitability of the process while simultaneously increasing the overcurrent capacity. SUMMARY OF THE UTILITY MODEL

[0004] The object of the present utility model is to provide a battery with a simple structure, easy assembly and high overcurrent capacity.

[0005] To achieve the above task, the present utility model provides the following technical solutions: The present utility model discloses a battery comprising: two single cells, each of the single cells having a first positive tab piece, a second positive tab piece, a first negative tab piece, and a second negative tab piece spaced apart from each other, wherein the terminal ends of the first positive tab piece and the first negative tab piece are arranged with an electrode near the outer edge of the single cell, and the terminal ends of the second positive tab piece and the second negative tab piece are arranged with the electrode near the center of the single cell; a cover plate assembly provided with a positive welding surface and a negative welding surface;wherein the first positive tab piece and the second positive tab piece of each of the individual cells are welded to the positive welding surface to form two spaced positive welding marks, and the first negative tab piece and the second negative tab piece of each of the individual cells are welded to the negative welding surface to form two spaced negative welding marks;

[0006] Advantageous effects of the battery of the present utility model: In the actual manufacturing process, the positive electrode is stacked with the first positive tab piece and the second positive tab piece, and the insulating membrane and the negative electrode are stacked with the first negative tab piece and the second negative tab piece, and then a single cell is manufactured through winding and a series of processes. The structure of such a single cell is simple and the manufacturing is relatively easy. In the assembly process, after the two single cells are stacked, the first two positive tab pieces, the second two positive tab pieces, the first two negative tab pieces, and the second two negative tab pieces are welded to the positive welding surface and the negative welding surface of the cover plate assembly, respectively, to form four positive welding marks and four negative welding marks.This can not only improve the connection strength between the single cell and the cover plate assembly, but also increase the welding area with the cover plate assembly, thereby increasing the overcurrent capacity.

[0007] Further aspects and advantages of the present utility model are partly set out in the following description and partly apparent from the following description or result from the practical application of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of the structure of two single cells according to the first embodiment of the present utility model; Fig. 2 is a schematic diagram of the welding of the two single cells and the cover plate according to the first embodiment of the present utility model; Fig. 3 is a schematic diagram of the deployed structure of one of the two single cells according to the first embodiment of the present utility model; Fig. 4 is a schematic diagram of the unfolded structure of the other of the two single cells according to the first embodiment of the present utility model; Fig. 5 is a schematic diagram of the structure of two single cells according to the second embodiment of the present utility model; Fig. 6 is a schematic diagram of the welding of the two single cells and the cover plate according to the second embodiment of the present utility model; Fig. 7 is a schematic diagram of the deployed structure of two single cells according to the second embodiment of the present utility model; Reference symbols of the figures:

[0008] 100, Single cell; 110, First positive tab piece; 120, Second positive tab piece; 130, First negative tab piece; 140, Second negative tab piece; 101, Positive weld mark; 102, Negative weld mark; 200, Cover plate assembly; 210, Positive weld surface; 220, Negative weld surface. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0009] The present utility model is described in more detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are provided only to illustrate the present utility model and not to limit the present utility model. Furthermore, it should be noted that, for the sake of simplicity of description, the accompanying drawings depict only a portion of the structure related to the present utility model, not the entire structure.

[0010] In the description of the present utility model, the terms "interconnected," "connected," and "attached" are to be understood in a broad sense, unless clearly stated and limited otherwise. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection via an intermediate medium; it may be the internal connection of two elements or the interaction relationship between two elements. The average person skilled in the art will be able to recognize the specific meanings of the above terms in the present utility model according to the specific circumstances.

[0011] In the description of the present embodiment, the terms "top," "bottom," "left," "right," "front," "rear," and other directions or positional relationships are based on the directions or positional relationships depicted in the accompanying drawings. These directions or positional relationships are intended solely for convenience of description and operational convenience. They do not indicate or imply that the designated device or element must have a particular direction or be constructed and operated in a particular direction, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used in the description for differentiation purposes only and have no particular meaning.

[0012] The present utility model discloses a battery. As described in the Fig. 2 and Fig. 6, the battery comprises two individual cells 100 and a cover plate assembly 200. Referring to the Fig. 1 and Fig. 5, each of the individual cells 100 has a first positive tab piece 110, a second positive tab piece 120, a first negative tab piece 130, and a second negative tab piece 140, which are spaced apart from one another. The terminal ends of the first positive tab piece 110 and the first negative tab piece 130 with the electrode are arranged near the outer edge of the individual cell 100, and the terminal ends of the second positive tab piece 120 and the second negative tab piece 140 with the electrode are arranged near the center of the individual cell 100. The cover plate assembly 200 is provided with a positive welding surface 210 and a negative welding surface 220. The first positive tab piece 110 and the second positive tab piece 120 of each of the individual cells 100 are welded to the positive welding surface 210 to form two spaced positive welding marks 101.The first negative tab piece 130 and the second negative tab piece 140 of each of the single cells 100 are welded to the negative welding surface 220 to form two spaced-apart negative welding marks 102. It should be understood that in the actual manufacturing process, the positive electrode is stacked with the first positive tab piece 110 and the second positive tab piece 120, the insulating membrane and the negative electrode are stacked with the first negative tab piece 130 and the second negative tab piece 140, and then the single cell 100 is manufactured through winding and a series of processes. Such a single cell 100 has a simple structure and can be manufactured relatively easily.During the assembly process, after stacking the two single cells 100, the two first positive tab pieces 110, the two second positive tab pieces 120, the two first negative tab pieces 130, and the two second negative tab pieces 140 are welded to the positive welding surface 210 and the negative welding surface 220 of the cover plate assembly 200, respectively, to form four positive welding marks 101 and four negative welding marks 102. This can not only improve the connection strength between the single cell 100 and the cover plate assembly 200, but also increase the welding area with the cover plate assembly 200, thereby increasing the overcurrent capacity.

[0013] It should be noted that in the present utility model, the positive welding surface 210 and the negative welding surface 220 may consist of a positive adapter and a negative adapter on the cover assembly 200, or may consist of a positive terminal pin and a negative terminal pin. The positive welding surface 210 and the negative welding surface 220 formed on the cover assembly 200 are prior art, and the positive welding surface 210 and the negative welding surface 220 are not described in detail here.

[0014] It should be noted that a single cell 100 typically includes a plurality of stacked electrode structures. The first positive tab piece 110 described above refers to the first positive tab piece 110 of the entire single cell 100 after stacking the first positive tab pieces of the plurality of electrodes; that is, the first positive tab piece 110 has a multi-layer structure. The second positive tab piece 120, the first negative tab piece 130, and the second negative tab piece 140 are also multi-layer structures.

[0015] In addition, the single cells 100 of the present embodiment may be a wound cell or a stacked cell, and the specific type may be selected depending on the actual need.

[0016] In the embodiment of the present utility model, the arrangement of the first positive tab piece 110, the second positive tab piece 120, the first negative tab piece 130 and the second negative tab piece 140 of the two single cells 100 can be adjusted as needed, and two specific arrangements will be described below. First embodiment:

[0017] The distance between the first positive tab piece 110 and the first negative tab piece 130 of one of the individual cells 100 (in Fig. 3) is greater than the distance between the second positive tab piece 120 and the second negative tab piece 140, and the distance between the first positive tab piece 110 and the first negative tab piece 130 of the other of the individual cells 100 (in Fig. 4) is smaller than the distance between the second positive tab piece 120 and the second negative tab piece 140. As shown in Fig. 2, the first positive tab piece 110 of one of the individual cells 100 is arranged correspondingly to the second positive tab piece 120 of the other of the individual cells 100, and the first negative tab piece 130 of one of the individual cells 100 is arranged correspondingly to the second negative tab piece 140 of the other of the individual cells 100. It can be seen that in the actual welding process, the longer first positive tab piece 110 of one of the individual cells 100 is welded correspondingly to the shorter second positive tab piece 120 of the other of the individual cells 100, and the longer first negative tab piece 130 of the other of the individual cells 100 is welded correspondingly to the shorter second negative tab piece 140 of the other of the individual cells 100, which is convenient for operation and conducive to improving assembly efficiency.At the same time, the staggered distribution is used to reduce the thickness of the tab weld and improve the process yield.

[0018] Optionally, an end of the first positive tab piece 110 of one of the individual cells 100 facing away from the outer edge of the individual cell 100 is spaced from an end of the second positive tab piece 120 of the other of the individual cells 100 facing away from the center of the individual cell 100. It can be seen that the first positive tab piece 110 of one of the individual cells 100 is spaced from the second positive tab piece 120 of the other of the individual cells 100 in order to avoid overlap of the first positive tab piece 110 and the second positive tab piece 120 during welding, which has an adverse effect on the performance of the battery.It should be noted that the gap dimension between the first positive tab piece 110 and the second positive tab piece 120 can be determined according to the dimension of the first positive tab piece 110 and the second positive tab piece 120 and the corresponding welding requirements, and the gap dimension is not particularly limited here.

[0019] Optionally, an end of the first negative tab piece 130 of one of the individual cells 100 facing away from the outer edge of the individual cell 100 is spaced from an end of the second negative tab piece 140 of the other of the individual cells 100 facing away from the center of the individual cell 100. It will be understood that the first negative tab piece 130 of one of the individual cells 100 is spaced from the second negative tab piece 140 of the other of the individual cells 100 to avoid overlap of the first negative tab piece 130 and the second negative tab piece 140 during welding, thereby preventing adverse effects on the performance of the battery.It should be noted that the gap dimension between the first negative tab piece 130 and the second negative tab piece 140 can be determined according to the dimension of the first negative tab piece 130 and the second negative tab piece 140 and the corresponding welding requirements, and the gap dimension is not particularly limited here.

[0020] Optionally, the dimensional range of the first positive tab piece 110 along the first direction can be 22 mm - 32 mm, and the dimensional range along the second direction can be 14 mm - 24 mm. Note that the first direction is the width direction of the electrode of the single cell 100, and the second direction is the length direction of the electrode of the single cell 100. Specifically, the dimension of the first positive tab piece 110 along the first direction can be 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm; The dimension of the first positive tab piece 110 along the second direction can be 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm. Of course, the dimension of the first positive tab piece 110 along the first direction and the second direction can take other values ​​within the above range and is not limited to the above examples.It is understood that if the dimension of the first positive tab piece 110 is too large, the manufacturing cost of the single cell 100 will increase and the dimension of the single cell 100 will increase, which is not conducive to improving the energy density of the battery. If the dimension of the first positive tab piece 110 is too small, this will result in insufficient overcurrent capacity of the battery. In the present embodiment, the dimension of the first positive tab piece 110 along the first direction is controlled within a range of 22mm-32mm, and the dimension along the second direction is controlled within a range of 14mm-24mm, thereby controlling the dimension of the single cell 100, which is conducive to ensuring the energy density of the battery, and ensuring that the battery has a high overcurrent capacity, which is conducive to improving the performance of the battery.

[0021] Optionally, the dimensional range of the second positive tab piece 120 along the first direction can be 10 mm - 20 mm, and the dimensional range along the second direction can be 14 mm - 24 mm. Specifically, the dimension of the second positive tab piece 120 along the first direction can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm; the dimension of the second positive tab piece 120 along the second direction can be 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm. Of course, the dimension of the second positive tab piece 120 along the first direction and the second direction may take other values ​​within the above ranges and is not limited to the above examples.It should be understood that if the dimension of the second positive tab piece 120 is too large, the manufacturing cost of the single cell 100 will increase and the dimension of the single cell 100 will increase, which is not conducive to improving the energy density of the battery. If the dimension of the second positive tab piece 120 is too small, this will result in insufficient overcurrent capacity of the battery. In the present embodiment, the dimension of the second positive tab piece 120 along the first direction is controlled within a range of 22mm-32mm, and the dimension along the second direction is controlled within a range of 14mm-24mm, thereby controlling the dimension of the single cell 100, which is conducive to ensuring the energy density of the battery, and ensuring that the battery has a high overcurrent capacity, which is conducive to improving the performance of the battery.

[0022] Furthermore, the dimension of the first positive tab piece 110 along the second direction is optionally equal to the dimension of the second positive tab piece 120 along the second direction.

[0023] Optionally, the dimensional range of the first negative tab piece 130 along the first direction can be 22 mm - 32 mm, and the dimensional range along the second direction can be 10 mm - 20 mm. Specifically, the dimension of the first negative tab piece 130 along the first direction can be 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm; the dimension of the first negative tab piece 130 along the second direction can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm. Of course, the dimension of the first negative tab piece 130 along the first direction and the second direction may take other values ​​within the above ranges and is not limited to the above examples.It should be understood that if the dimension of the first negative tab piece 130 is too large, the manufacturing cost of the single cell 100 will increase and the dimension of the single cell 100 will increase, which is not conducive to improving the energy density of the battery. If the dimension of the first negative tab piece 130 is too small, this will result in insufficient overcurrent capacity of the battery. In the present embodiment, the dimension of the first negative tab piece 130 along the first direction is controlled within a range of 22mm-32mm, and the dimension along the second direction is controlled within a range of 14mm-24mm, thereby controlling the dimension of the single cell 100, which is conducive to ensuring the energy density of the battery, and ensuring that the battery has a high overcurrent capacity, which is conducive to improving the performance of the battery.

[0024] Optionally, the dimension of the second negative tab piece 140 along the first direction ranges can be 10 mm to 20 mm, and the dimension along the second direction ranges can be 10 mm to 20 mm. The dimension of the second negative tab piece 140 along the first direction can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm. The dimension of the second negative tab piece 140 along the second direction can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm. Of course, the dimension of the second negative tab piece 140 along the first direction and the second direction is selected from other values ​​within the above range and is not limited to the above examples.It is understood that if the dimension of the second negative tab piece 140 is too large, the manufacturing cost of the single cell 100 will increase, and increasing the dimension of the single cell 100 is not conducive to improving the energy density of the battery. If the dimension of the second negative tab piece 140 is too small, the battery will have insufficient overcurrent capacity. In the present embodiment, the dimension of the second negative tab piece 140 along the first direction is controlled within a range of 22mm-32mm, and the dimension along the second direction is controlled within a range of 14mm-24mm. This allows the dimension of the single cell 100 to be controlled, which is conducive to ensuring the energy density of the battery, and ensuring that the battery has a high overcurrent capacity, which is conducive to improving the battery's performance.

[0025] Optionally, the dimension of the positive weld mark 101 along the first direction ranges from 3 mm to 13 mm, and the dimension along the second direction ranges from 9 mm to 19 mm. Specifically, the dimension of the positive weld mark 101 along the first direction may be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm; the dimension along the second direction may be 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm. Of course, the dimension of the positive weld mark 101 along the first direction and the second direction selects other values ​​within the above ranges and is not limited to the above examples.It is understood that if the positive welding mark 101 is too small, the overcurrent capacity of the battery will be reduced, and if the positive welding mark 101 is too large, it will easily lead to internal short circuits and increase the probability of battery failure. In the present embodiment, the dimensions of the positive welding mark 101 along the first direction and the second direction are controlled to be 3mm-13mm and 9mm-19mm, respectively. This ensures that there is sufficient welding area between the single cell 100 and the cover plate assembly 200, which is conducive to ensuring the overcurrent capacity of the battery, and reduces the probability of internal short circuits, which is conducive to improving the working safety of the battery.

[0026] Optionally, the dimension range of the negative weld mark 102 along the first direction can be 6mm-16mm, and the dimension range along the second direction can be 8mm-18mm. Specifically, the dimension of the negative weld mark 102 along the first direction can be 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm; the dimension along the second direction can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm. Of course, the dimension of the negative weld mark 102 along the first direction and the second direction can be selected from other values ​​within the above ranges and is not limited to the above examples.It is understood that if the negative welding mark 102 is too small, the overcurrent capacity of the battery will be reduced, and if the negative welding mark 102 is too large, internal short circuits are likely to occur, increasing the likelihood of battery failure. In the present embodiment, the dimensions of the negative welding mark 102 along the first direction and the second direction are controlled to be 6mm-16mm and 8mm-18mm, respectively. This ensures that there is sufficient welding area between the single cell 100 and the cover plate assembly 200, which is conducive to ensuring the overcurrent capacity of the battery, and reduces the likelihood of internal short circuits, thus improving the operational safety of the battery.

[0027] Optionally, the two positive welding marks 101 formed in the positive welding surface 210 of a single cell 100 have the same shape, and the area ratio of the first positive tab piece 110 to the second positive tab piece 120 is 1.5:1-2:1; the area ratio of the second positive tab piece 120 to the positive welding mark 101 is 2:1-3:1. It is understood that the positive welding marks 101 formed in the positive welding surface 210 of the first positive tab piece 110 and the second positive tab piece 120 have the same shape, which, on the one hand, promotes welding and, on the other hand, ensures that the first positive tab piece 110 and the second positive tab piece 120 have the same overcurrent capacity.

[0028] The area ratio of the first positive tab piece 110 to the second positive tab piece 120 can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2:1, or other values ​​within the above range, without limitation to the examples. The area ratio of the second positive tab piece 120 to the positive weld mark 101 can be 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, or 3:1, or other values ​​within the above range, without limitation to the examples.

[0029] Optionally, the two negative weld marks 102 formed in the negative welding surface 220 of a single cell 100 have the same shape, and the area ratio of the first negative tab piece 130 to the second negative tab piece 140 is 1.5:1-2:1; and / or the area ratio of the second negative tab piece 140 to the negative weld mark 102 is 1.2:1-1.8:1. It is understood that the shape of the positive weld mark 101 formed in the positive welding surface 210 by the first negative tab piece 130 and the second negative tab piece 140 is identical, which is favorable for welding, while the first positive tab piece 110 and the second positive tab piece 120 have the same overcurrent capacity.The area ratio of the first negative tab piece 130 to the second negative tab piece 140 can optionally be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2:1, or can assume other values ​​within the above range, without limitation to the examples. The area ratio of the second negative tab piece 140 to the negative weld mark 102 is 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, or 1.8:1, and can also assume other values ​​within the above range, without limitation to the examples.

[0030] In a particular example, the first positive tab piece 110, the second positive tab piece 120, the first negative tab piece 130, the second negative tab piece 140, the positive weld mark 101 and the negative weld mark 102 are all rectangular, the dimension of the first positive tab piece 110 is 27mm*19mm, the dimension of the second positive tab piece 120 is 15mm*19mm, the dimension of the positive weld mark 101 is 14mm*8mm, the dimension of the first negative tab piece 130 is 27mm*15mm, the dimension of the second negative tab piece 140 is 15mm*15mm, and the dimension of the second negative weld mark 102 is 13mm*11mm. Second embodiment:

[0031] With reference to the Fig.5-7, the ranges of the parameters of the first positive tab piece 110, the second positive tab piece 120, the first negative tab piece 130, the second negative tab piece 140, the positive weld mark 101, and the negative weld mark 102 of the present embodiment are the same as those of the first embodiment, except that in the present embodiment, the two first positive tab pieces 110 are correspondingly arranged, and the ends of the two first positive tab pieces 110 are spaced apart from each other; the two first negative tab pieces 130 are correspondingly arranged, and the ends of the two first negative tab pieces 130 are spaced apart from each other.

[0032] In a particular example, the battery's fast charging capacity reaches 5C (i.e., the maximum overcurrent requirement is 835A). Then, the positive overcurrent area must be 208.75mm 2distributed between the two first positive tab pieces 110 and the two second positive tab pieces 120, so that the area of ​​each positive welding mark 101 is guaranteed to be greater than 52.1875mm 2 Likewise, the area of ​​the positive welding mark 101 is guaranteed to be larger than 41.75mm 2 .

[0033] In this specification, the use of the terms "some embodiments," "other embodiments," etc., means that the particular features, structures, materials, or properties described in connection with the embodiment or example are included in at least one embodiment or at least one example of the present utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the described particular features, structures, materials, or properties may be combined as appropriate in one or more embodiments or examples.

[0034] The above embodiments of the present utility model are obviously only examples to illustrate the present utility model and do not constitute limitations on the implementation methods of the present utility model. For an average person skilled in the art, obvious modifications, adaptations, and substitutions can be made without departing from the scope of the present utility model. Enumerating all implementation methods is unnecessary and impossible here. Modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model are intended to be included within the scope of the claims of the present utility model.

Claims

[1] Battery comprising: two single cells (100), each of the single cells (100) having a first positive tab piece (110), a second positive tab piece (120), a first negative tab piece (130) and a second negative tab piece (140) which are spaced apart from one another, the terminal ends of the first positive tab piece (110) and the first negative tab piece (130) being arranged with an electrode near the outer edge of the single cell (100) and the terminal ends of the second positive tab piece (120) and the second negative tab piece (140) being arranged with the electrode near the center of the single cell (100); a cover plate assembly (200) provided with a positive welding surface (210) and a negative welding surface (220); wherein the first positive tab piece (110) and the second positive tab piece (120) of each of the individual cells (100) are welded to the positive welding surface (210) to form two spaced positive welding marks (101), and the first negative tab piece (130) and the second negative tab piece (140) of each of the individual cells (100) are welded to the negative welding surface (220) to form two spaced negative welding marks (102). [2] Battery according to claim 1, characterized in that the two first positive tab pieces (110) are arranged correspondingly and the ends of the two first positive tab pieces (110) are spaced apart from each other; the two first negative tab pieces (130) are arranged correspondingly and the ends of the two first negative tab pieces (130) are spaced apart from each other. [3] Battery according to claim 1 or 2, characterized in that the distance between the first positive tab piece (110) and the first negative tab piece (130) of one of the individual cells (100) is greater than the distance between the second positive tab piece (120) and the second negative tab piece (140), and the distance between the first positive tab piece (110) and the first negative tab piece (130) of the other of the individual cells (100) is smaller than the distance between the second positive tab piece (120) and the second negative tab piece (140); wherein the first positive tab piece (110) of one of the individual cells (100) and the second positive tab piece (120) of the other of the individual cells (100) are arranged correspondingly, and the first negative tab piece (130) of one of the individual cells (100) and the second negative tab piece (140) of the other of the individual cells (100) are arranged correspondingly. [4] Battery according to claim 3, characterized in that an end of the first positive tab piece (110) of one of the individual cells (100) facing away from the outer edge of the individual cell (100) is spaced from an end of the second positive tab piece (120) of the other of the individual cells (100) facing away from the center of the individual cell (100); an end of the first negative tab piece (130) of one of the individual cells (100) facing away from the outer edge of the individual cell (100) is spaced from an end of the second negative tab piece (140) of the other of the individual cells (100) facing away from the center of the individual cell (100). [5] Battery according to claim 3, characterized in that the dimensional range of the first positive tab piece (110) along the first direction is 22mm-32mm and the dimensional range along the second direction is 14mm-24mm; the dimensional range of the second positive tab piece (120) along the first direction is 10mm-20mm and the dimensional range along the second direction is 14mm-24mm. [6] Battery according to claim 3, characterized in that the dimensional range of the first negative tab piece (130) along the first direction is 22mm-32mm and the dimensional range along the second direction is 10mm-20mm; the dimensional range of the second negative tab piece (140) along the first direction is 10mm-20mm and the dimensional range along the second direction is 10mm-20mm. [7] Battery according to claim 3, characterized in that the dimensional range of the positive welding mark (101) along the first direction is 3mm-13mm and the dimensional range along the second direction is 9mm-19mm. [8] Battery according to claim 3, characterized in that the dimensional range of the negative welding mark (102) along the first direction is 6mm-16mm and the dimensional range along the second direction is 8mm-18mm. [9] Battery according to claim 3, characterized in that the two positive welding marks (101) formed on the positive welding surface (210) of one of the individual cells 100 are uniform and the area ratio of the first positive tab piece (110) to the second positive tab piece (120) is 1.5:1-2:1; and / or the area ratio of the second positive tab piece (120) to the positive welding mark (101) is 2:1-3:

1. [10] Battery according to claim 3, characterized in that the two negative welding marks (102) formed on the negative welding surface (220) of one of the individual cells (100) are uniform and the area ratio of the first negative tab piece (130) to the second negative tab piece (140) is 1.5:1-2:1; and / or the area ratio of the second negative tab piece (140) to the negative welding mark (102) is 1.2:1-1.8:

1. [11] Battery according to one of claims 1 to 10, characterized in that the individual cells (100) are a wound cell.

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