Soft package battery cell and battery pack

Abstract

The utility model provides a soft package battery cell and a battery pack, the soft package battery cell comprises a plurality of pole groups, and the plurality of pole groups are sequentially connected end to end along a first direction; the plurality of pole groups are arranged in the shell, accommodating positions are formed in the shell, and the accommodating positions and the pole groups are arranged in a one-to-one correspondence manner. According to the soft package battery cell, through the cooperation of the plurality of pole groups and the shell, a single relatively long battery cell of an original CTP battery cell is improved into a connection mode of connecting the plurality of pole groups in series, so that the rate capability of the battery cell can be effectively improved, the safety performance of the battery cell can be improved, the production is more convenient, and meanwhile, the ohmic polarization of the pole pieces is reduced.

Description

Technical Field

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

[0002] Lithium-ion batteries have the advantages of long cycle, low self-discharge, and high voltage platform. With the increase in the range of new energy electric vehicles and the requirement to shorten the charging time, the energy density and rate performance of power battery packs are becoming increasingly higher. In order to improve the energy density of the PACK, CTP technology (cell to pack, module-free power battery pack) is proposed to reduce the weight of the module structure in the PACK, such as the "blade battery" of the square battery cell and the soft-pack 590 battery cell.

[0003] The current CTP battery cell is realized by increasing the length of the battery cell and eliminating the structural parts of the module. The increase in the length of the battery cell increases the length of the battery cell's pole piece, resulting in obvious ohmic polarization of the battery cell pole piece, affecting the current density distribution of the pole piece, and causing the battery cell's charging rate performance to decrease. And the increase in the length of the pole piece also brings great difficulty to the manufacturing of the battery cell. Although square batteries have certain advantages in grouping, most square batteries use the method of parallel connection of pole groups into the shell during the assembly process, which makes it difficult to screen out bad batteries through K value screening when the single pole group self-discharges. In addition, in terms of safety, the current CTP battery cell adopts a long battery cell structure design, which is not conducive to the development of the application of ternary system in CTP. Due to the increase in the length of the battery cell, the capacity and energy density of the battery cell will also be higher than that of conventional batteries, thereby increasing the design difficulty of ternary system batteries.

[0004] Therefore, it is necessary to design a soft-pack battery cell to solve the above problems. Utility Model Content

[0005] In view of this, in order to overcome the defects of the prior art, the utility model provides a soft-pack battery cell and a battery pack, which effectively solves the problem that the length of the existing CTP battery cell increases, which increases the length of the battery cell electrode piece, resulting in obvious ohmic polarization of the battery cell electrode piece and difficulty in manufacturing, and the parallel connection of the electrode group into the shell cannot quickly screen out bad batteries.

[0006] According to the first aspect of the utility model, a soft-pack battery cell is provided, wherein the soft-pack battery cell includes a pole group, the number of the pole groups is multiple, and the multiple pole groups are connected in sequence end to end along a first direction; a shell, the multiple pole groups are arranged inside the shell, and the shell is formed with accommodating positions, and the accommodating positions are arranged one-to-one corresponding to the pole groups.

[0007] Preferably, the pole group includes a first pole piece, a second pole piece and a diaphragm, and the diaphragm is arranged between the first pole piece and the second pole piece.

[0008] Preferably, the second pole piece includes a first side and a second side arranged in the first direction, and at least one of the first side and the second side is located on the outside of the first pole piece in the first direction; the first pole piece includes a third side and a fourth side arranged in the first direction, and a first preset distance is set between the first side and the third side and between the second side and the fourth side; the first preset distance is greater than 1 mm.

[0009] Preferably, the second pole piece includes a first side edge and a second side edge arranged in the first direction, and the first side edge and the second side edge are both located on the outside of the first pole piece in the first direction; the first pole piece includes a third side edge and a fourth side edge arranged in the first direction, and a first preset distance is set between the first side edge and the third side edge and between the second side edge and the fourth side edge; the first preset distance is greater than 1 mm.

[0010] Preferably, the second pole piece includes a fifth side and a sixth side arranged in the second direction, and the fifth side and the sixth side are both located on the outside of the first pole piece; the first pole piece includes a seventh side and an eighth side arranged in the second direction, and a second preset distance is set between the fifth side and the seventh side and between the sixth side and the eighth side; the second preset distance is greater than 0.5 mm.

[0011] Preferably, the diaphragm includes a ninth side and a tenth side arranged in the first direction and an eleventh side and a twelfth side arranged in the second direction, the ninth side and the tenth side are both located on the outside of the second pole piece in the first direction, and the eleventh side and the twelfth side are both located on the outside of the second pole piece in the second direction; a third preset distance is set between the ninth side and the first side and between the tenth side and the second side, and the third preset distance is greater than 1.2 mm; a fourth preset distance is set between the eleventh side and the fifth side and between the twelfth side and the sixth side, and the fourth preset distance is greater than 0.2 mm.

[0012] Preferably, the number of the pole groups is 2-5.

[0013] Preferably, each of the pole groups comprises a first pole lug arranged at a first end in the first direction and a second pole lug arranged at a second end in the first direction; the size of the first pole lug and the second pole lug in the first direction is 5-10 mm.

[0014] Preferably, the second pole ear of one of the pole groups in the first direction is connected to the first pole ear of the adjacent pole group in the first direction through a connecting plate; each of the pole groups also includes an axis arranged in the first direction, and the distance between the axes of two adjacent pole groups in the second direction is less than 1 mm.

[0015] According to a second aspect of the present invention, a battery pack is provided, wherein the battery pack comprises the soft-pack battery cell as described above.

[0016] According to the soft-pack battery cell of the utility model, through the cooperation of multiple pole groups and shells, the single longer battery cell of the original CTP battery cell is improved into a connection mode of multiple pole groups connected in series, which can effectively improve the rate performance of the battery cell, improve the safety performance of the battery cell, make production more convenient, and reduce the ohmic polarization of the pole piece.

[0017] 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

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram showing the structure of a pole group according to an embodiment of the utility model is shown;

[0020] Figure 2 Another schematic structural diagram of a pole group according to an embodiment of the utility model is shown;

[0021] Figure 3 A schematic structural diagram of a housing according to an embodiment of the utility model is shown;

[0022] Figure 4 A schematic diagram showing the structure of a pole group after pre-welding according to an embodiment of the utility model is shown;

[0023] Figure 5 A schematic diagram showing the structure of the electrode group after the electrode lugs are cut according to an embodiment of the utility model;

[0024] Figure 6 A schematic diagram showing the structure of the pole groups after the pole groups according to the embodiment of the utility model are connected;

[0025] Figure 7 A schematic diagram showing the structure of a pole group after final welding according to an embodiment of the utility model;

[0026] Figure 8 A schematic structural diagram showing the assembly of a pole group according to an embodiment of the utility model;

[0027] Fig. 9 A schematic structural diagram showing the completed assembly of a pole group according to an embodiment of the utility model is shown.

[0028] Figure markings: 1-pole group; 2-shell; 201-accommodation position; 202-side sealing edge; 3-first pole piece; 301-third side; 302-fourth side; 303-seventh side; 304-eighth side; 305-first pole ear; 4-second pole piece; 401-first side; 402-second side; 403-fifth side; 404-sixth side; 405-second pole ear; 5-diaphragm; 501-ninth side; 502-tenth side; 503-eleventh side; 504-twelfth side; 6-connecting tape; 7-pre-welding position; 8-connecting piece; 9-pole handle; 10-protective tape; S1-first direction; S2-second direction; S3-axis. DETAILED DESCRIPTION

[0029] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0030] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0031] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] According to a first aspect of the present invention, a soft-pack battery cell is provided. Figures 1 to 9 As shown, the soft-pack battery cell is used for a power battery cell PACK using CTP technology, and the soft-pack battery cell includes an electrode group 1 and a shell 2.

[0034] In the following description, reference will be made to Figures 1 to 9 The detailed structure of the electrode group 1 and the shell 2 of the soft-pack battery cell is described in detail. Figure 1 , Figure 2 and Figure 6 As shown, in the embodiment, two directions are involved, namely a first direction S1 and a second direction S2. The first direction S1 can be understood as Figure 1 , Figure 2 and Figure 6 The second direction S2 can be understood as the direction from left to right in Figure 1 and Figure 2 In addition, the axis S3 of the pole group 1 is also involved, such as Figure 6 As shown in , the axis S3 is the axisymmetric line of the pole group 1 in the first direction S1.

[0035] like Figures 1 to 3As shown, in an embodiment, the soft-pack battery cell includes a plurality of pole groups 1, and the plurality of pole groups 1 are connected end to end in a first direction S1. Since the current CTP battery cell is realized by increasing the length of the battery cell and canceling the structural parts of the module, the difficulty of manufacturing the battery cell will increase after the length of the pole piece increases. By improving the pole piece with excessive length in the original structure into a structure in which a plurality of pole groups 1 are connected, the difficulty of manufacturing can be effectively reduced; in addition, although the square battery cell has certain advantages in grouping, most of the square battery cells are assembled by connecting the pole groups in parallel into the shell, which results in that when the single pole group self-discharges, it is difficult to screen out the bad battery cells by K value screening. Therefore, the multiple pole groups 1 are connected in series to avoid the problem of self-discharge and difficulty in troubleshooting the bad battery cells.

[0036] The soft-pack battery cell also includes a housing 2, and a plurality of electrode groups 1 are arranged inside the housing 2. The housing 2 is formed with accommodation positions 201, and the accommodation positions 201 are arranged one-to-one with the electrode groups 1. For example, in the embodiment, three electrode groups 1 are connected in series in the first direction S1, so the corresponding housing 2 needs to be provided with three accommodation positions 201. In addition, Figure 3 As shown, the axial symmetry line set in the length direction of the shell 2 is the fold of the shell 2, and the three accommodating positions 201 of the shell 2 on the upper part of the axial symmetry line and the three accommodating positions 201 on the lower part of the axial symmetry line are matched to form three complete accommodating positions 201 for assembling the pole group 1.

[0037] The soft-pack battery cell can overcome the problems of poor rate performance and high safety risk of existing CTP batteries. By producing multiple electrode groups 1 in series, the length of the overall electrode piece is reduced, making production more convenient, while reducing the ohmic polarization of the electrode piece and improving the charging rate performance of the battery cell. After changing from a single long electrode group to multiple short electrode groups 1, the safety performance of the battery cell is also greatly improved.

[0038] Preferably, if Figure 1 and Figure 2 As shown, the electrode group 1 includes a first electrode piece 3, a second electrode piece 4 and a diaphragm 5, and the diaphragm 5 is arranged between the first electrode piece 3 and the second electrode piece 4. The electrode group 1 can be formed by stacking the electrode pieces and the diaphragm 5.

[0039] Preferably, in the embodiment, the number of the first pole piece 3, the second pole piece 4 and the diaphragm 5 are all multiple, the multiple first pole pieces 3 and the multiple second pole pieces 4 are stacked in sequence, and a diaphragm 5 is provided between two adjacent pole pieces. The number of the first pole piece 3, the second pole piece 4 and the diaphragm 5 can be specifically selected as needed.

[0040] Preferably, if Figure 1 and Figure 2As shown, in the embodiment, the number of electrode groups 1 of the battery cell needs to be reasonably designed according to the overall size, capacity, energy density and charging rate requirements of the battery cell. Preferably, the number of electrode groups 1 is 2 to 5. When the use is satisfied, the length will not be too long, the manufacturing is simple, and the space utilization rate is improved. In addition, the size of the electrode group 1 can be specifically selected according to different usage scenarios.

[0041] Preferably, if Figure 1 and Figure 2 As shown, in the embodiment, considering the manufacturing capacity of each pole group 1, it is necessary to reasonably design the coating amounts of the first pole piece 3, the second pole piece 4 and the diaphragm 5.

[0042] Specifically, Figure 2 As shown, in the first embodiment, the second pole piece 4 includes a first side 401 and a second side 402 arranged in the first direction S1, and at least one of the first side 401 and the second side 402 is located on the outside of the first pole piece 3 in the first direction S1, that is, the second pole piece 4 at least partially covers the first pole piece 3.

[0043] The first pole piece 3 includes a third side 301 and a fourth side 302 arranged in the first direction S1, a first preset distance is set between the first side 401 and the third side 301, and a first preset distance is also set between the second side 402 and the fourth side 302. The first preset distance is greater than 1 mm.

[0044] like Figure 1 As shown, in the second embodiment, the second pole piece 4 includes a first side 401 and a second side 402 arranged in the first direction S1, and the first side 401 and the second side 402 are both located outside the first pole piece 3 in the first direction S1, that is, the second pole piece 4 completely covers the first pole piece 3.

[0045] The first pole piece 3 includes a third side 301 and a fourth side 302 arranged in the first direction S1, a first preset distance is set between the first side 401 and the third side 301, and a first preset distance is also set between the second side 402 and the fourth side 302. The first preset distance is greater than 1 mm.

[0046] In addition, whether in Figure 2 In the first embodiment shown, Figure 1 In the second embodiment shown, the second pole pieces 4 are all formed as the negative poles of the pole group 1 , and the first pole pieces 3 are all formed as the positive poles of the pole group 1 .

[0047] Preferably, if Figure 1 and Figure 2As shown, in the first embodiment or the second embodiment, the second pole piece 4 includes a fifth side 403 and a sixth side 404 arranged in the second direction S2, and the fifth side 403 and the sixth side 404 are both located on the outside of the first pole piece 3; that is, in the second direction S2, the second pole piece 4 completely covers the first pole piece 3.

[0048] The first pole piece 3 includes a seventh side 303 and an eighth side 304 arranged in the second direction S2, and a second preset distance is set between the fifth side 403 and the seventh side 303 and between the sixth side 404 and the eighth side 304; the second preset distance is greater than 0.5 mm.

[0049] Preferably, if Figure 1 and Figure 2 As shown, in the first embodiment or the second embodiment, the diaphragm 5 includes a ninth side 501 and a tenth side 502 arranged in the first direction S1, and an eleventh side 503 and a twelfth side 504 arranged in the second direction S2. The ninth side 501 and the tenth side 502 are both located outside the second pole piece 4 in the first direction S1, and the eleventh side 503 and the twelfth side 504 are both located outside the second pole piece 4 in the second direction S2, that is, the diaphragm 5 completely covers the second pole piece 4.

[0050] A third preset distance is set between the ninth side 501 and the first side 401, and between the tenth side 502 and the second side 402, and the third preset distance is greater than 1.2 mm. A fourth preset distance is set between the eleventh side 503 and the fifth side 403, and between the twelfth side 504 and the sixth side 404, and the fourth preset distance is greater than 0.2 mm.

[0051] The first pole piece 3 and the second pole piece 4 designed by the above-mentioned coating amount can be manufactured as follows: Figure 1 and Figure 2 The pole group 1 shown can effectively improve safety.

[0052] Preferably, if Figure 1 and Figure 2 As shown, in the embodiment, a plurality of connecting tapes 6 are provided on the peripheral side of the electrode group 1 , which can preliminarily fix the first electrode sheet 3 , the second electrode sheet 4 and the diaphragm 5 .

[0053] Preferably, if Figure 4 As shown, in the embodiment, the pole ears of the pole group 1 after lamination are pre-welded by ultrasonic wave, thereby forming pre-welding positions 7 for subsequent welding and series connection.

[0054] Preferably, if Figure 5As shown, in the embodiment, the pole lugs of the pre-welded pole group 1 need to be cut. Each pole group 1 may include a first pole lug 305 arranged at the first end in the first direction S1 and a second pole lug 405 arranged at the second end in the first direction S1. The size of the first pole lug 305 and the second pole lug 405 in the first direction S1 is 5-10 mm, which is convenient for subsequent connection and molding.

[0055] Preferably, if Figure 6 and Figure 7 As shown, in the embodiment, the second pole ear 405 of one pole group 1 in the first direction S1 is connected to the first pole ear 305 of the adjacent pole group 1 in the first direction S1 through a connecting piece 8. The connecting piece 8 can be, for example, a copper-to-aluminum sheet, and the pole ears of two adjacent pole groups 1 are welded by laser welding technology. Adjacent pole groups 1 are connected by copper-to-aluminum metal sheets. When an external short circuit occurs, the current exceeds the maximum load of the copper-to-aluminum metal sheet, resulting in a short circuit inside the battery cell, thereby protecting the battery cell from fire or explosion.

[0056] Preferably, if Figure 6 As shown, in the embodiment, each pole group 1 may further include an axis S3 arranged in the first direction S1, and the distance between the axes S3 of two adjacent pole groups 1 in the second direction S2 is less than 1 mm, that is, the misalignment size of the axis S3 of each pole group 1 is less than 1 mm, thereby ensuring the connection accuracy.

[0057] Preferably, if Figure 7 As shown, in the embodiment, two ends of the plurality of pole groups 1 connected in series in the first direction S1 are connected with pole handles 9, and the pole handles 9 are connected by laser welding. A protective tape 10 is pasted at the connection to prevent the welding marks from scratching the housing 2, and the protective tape 10 can be, for example, a high-temperature tape.

[0058] Preferably, if Figure 3 As shown, the shell 2 can be designed with a soft-package punching size according to the size of the pole group 1, so that the internal space after punching can accommodate the pole group 1 without space redundancy.

[0059] Preferably, if Figure 3 As shown, the housing 2 may be an aluminum-plastic film.

[0060] Preferably, in an embodiment, Figure 8 As shown in the assembly process of the shell 2 and the pole group 1, the corresponding number of pole groups 1 and the housing positions 201 of the shell 2 are aligned and assembled, and the shell 2 is bent at the fold, and the surrounding side of the shell 2 is sealed by a top side sealing machine to form a side sealing edge 202 to ensure sealing.

[0061] Preferably, if Figure 8As shown, in the embodiment, the space between the electrode groups 1 can be used as electrolyte storage space, which increases the storage space for the electrolyte, ensures a long cycle life of the battery cell, and solves the shortcomings of low liquid retention in soft-pack batteries and lower cycle life than square batteries.

[0062] Preferably, if Fig. 9 As shown, the soft-pack battery cell is formed. When the soft-pack battery cell is charged and discharged, the size of the electrode group 1 becomes shorter, which can reduce the influence of the ohmic polarization of the long battery cell and improve the battery cell rate performance. When the battery cell is punctured, a single electrode group 1 undergoes thermal runaway, and the heat generated and the intensity are lower than the existing CTP battery cell. It can also solve the problem that the existing square CTP battery cell is not suitable for the development of ternary system materials.

[0063] The soft-pack battery cell improves the original CTP battery cell's single long cell into a connection mode of multiple electrode groups in series through the cooperation of multiple electrode groups and shells, which can effectively improve the battery cell rate performance, enhance the battery cell safety performance, make production more convenient, and reduce the ohmic polarization of the electrode piece.

[0064] In addition, according to a second aspect of the present invention, a battery pack is provided, the battery pack comprising the soft-pack battery cell as described above.

[0065] 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 soft-pack battery cell, characterized in that: The soft-pack battery cell comprises: A pole group, wherein the number of the pole groups is multiple, and the multiple pole groups are connected end to end in sequence along a first direction; A shell, wherein the plurality of pole groups are arranged inside the shell, and the shell is formed with accommodation positions, and the accommodation positions are arranged in one-to-one correspondence with the pole groups; The electrode group includes a first electrode piece, a second electrode piece and a diaphragm, and the diaphragm is arranged between the first electrode piece and the second electrode piece; The second pole piece includes a first side and a second side arranged in the first direction, and at least one of the first side and the second side is located outside the first pole piece in the first direction; the first pole piece includes a third side and a fourth side arranged in the first direction, and a first preset distance is set between the first side and the third side and between the second side and the fourth side; the first preset distance is greater than 1 mm, or The second pole piece includes a first side and a second side arranged in the first direction, and the first side and the second side are both located on the outside of the first pole piece in the first direction; the first pole piece includes a third side and a fourth side arranged in the first direction, and a first preset distance is set between the first side and the third side and between the second side and the fourth side; the first preset distance is greater than 1 mm.

2. The soft-pack battery cell according to claim 1, characterized in that: The second pole piece includes a fifth side and a sixth side arranged in the second direction, and the fifth side and the sixth side are both located outside the first pole piece; The first pole piece includes a seventh side and an eighth side arranged in the second direction, and a second preset distance is set between the fifth side and the seventh side and between the sixth side and the eighth side; The second preset distance is greater than 0.5 mm.

3. The soft-pack battery cell according to claim 2, characterized in that: The diaphragm includes a ninth side and a tenth side arranged in the first direction, and an eleventh side and a twelfth side arranged in the second direction, the ninth side and the tenth side are both located outside the second pole piece in the first direction, and the eleventh side and the twelfth side are both located outside the second pole piece in the second direction; A third preset distance is set between the ninth side and the first side, and between the tenth side and the second side, and the third preset distance is greater than 1.2 mm; A fourth preset distance is set between the eleventh side and the fifth side and between the twelfth side and the sixth side, and the fourth preset distance is greater than 0.2 mm.

4. The soft-pack battery cell according to claim 1, characterized in that: The number of the pole groups is 2-5.

5. The soft-pack battery cell according to claim 1, characterized in that: Each of the pole groups includes a first pole lug disposed at a first end in the first direction and a second pole lug disposed at a second end in the first direction; The dimensions of the first pole tab and the second pole tab in the first direction are 5-10 mm.

6. The soft-pack battery cell according to claim 5, characterized in that: The second pole lug of one of the pole groups in the first direction is connected to the first pole lug of the adjacent pole group in the first direction via a connecting piece; Each of the pole groups further includes an axis arranged in the first direction, and a distance between the axes of two adjacent pole groups in the second direction is less than 1 mm.

7. A battery pack, characterized in that: The battery pack comprises the soft-pack battery cell according to any one of claims 1 to 6.

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