Single battery and battery pack

Abstract

The utility model relates to the technical field of power batteries, in particular to a single battery and a battery pack. Wherein the single battery comprises a shell, a pole arranged on the shell and a battery cell accommodated in the shell, and the battery cell comprises a battery cell body and a tab group connected to one end of the battery cell body. The connecting piece comprises a connecting part, a mounting part, a protecting part and a first bending part, the mounting part is connected to one side of the connecting part, the protecting part is connected to one side, far away from the connecting part, of the mounting part, the mounting part and the protecting part are respectively arranged on two opposite sides in the thickness direction of the tab group, and the tab group is arranged between the mounting part and the protecting part in the thickness direction of the tab group; the mounting part and the protection part are electrically connected with the tab group, and the connecting part is electrically connected with the pole; wherein the first bending part is positioned on the outer side of the tab group, and the first bending part is connected between the mounting part and the protection part. According to the invention, the problem of high difficulty in process folding and welding of the long tab can be solved, and the yield of the single battery is improved.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a single cell and a battery pack. Background Technology

[0002] In the current aluminum-cased battery cell manufacturing process, the increased thickness of the cell presents a challenge in welding the tabs. The welding capabilities of conventional ultrasonic welding and laser welding have, to some extent, limited further increases in cell thickness. Simultaneously, increased cell thickness means increased tab connection length, but the folding problem caused by long tabs in traditional winding and folding methods remains unresolved. Furthermore, the tabs of traditional cells are prone to contact with the welding head during welding, leading to damage and affecting cell yield. Utility Model Content

[0003] This application provides a single-cell battery and a battery pack to solve the technical problem of increased tab connection length in existing single-cell batteries.

[0004] On one hand, this application provides a single-cell battery, including: a casing, terminals, a cell, and a connector, wherein the terminals are disposed in the casing; the cell is housed in the casing, and the cell includes a cell body and a tab assembly connected to one end of the cell body; the connector includes a connecting portion, a mounting portion, a protective portion, and a first bending portion; the mounting portion is connected to one side of the connecting portion; the protective portion is connected to the side of the mounting portion away from the connecting portion, the mounting portion and the protective portion are respectively disposed on opposite sides in the thickness direction of the tab assembly, and the tab assembly is disposed between the mounting portion and the protective portion in the thickness direction of the tab assembly; both the mounting portion and the protective portion are electrically connected to the tab assembly, and the connecting portion is electrically connected to the terminals; the first bending portion is located on the outside of the tab assembly, and the first bending portion is connected between the mounting portion and the protective portion.

[0005] As one optional embodiment of this solution, the single battery cell has a first direction, a second direction, and a third direction that intersect each other in pairs; the tab assembly is connected to the end of the cell body in the first direction; the cell includes a first cell and a second cell distributed along the third direction, and the tab assemblies of the first cell and the second cell are distributed along the second direction; the mounting part includes a first mounting part and a second mounting part, which are respectively connected to the two ends of the connecting part along the second direction; the protection part includes a first protection part and a second protection part, and along the thickness direction of the tab assembly, the tab assembly of the first cell is disposed between the first protection part and the first mounting part, and the tab assembly of the second cell is disposed between the second protection part and the second mounting part.

[0006] As one of the optional embodiments of this solution, the battery cell further includes a third battery cell and a fourth battery cell distributed along a third direction. The first battery cell and the second battery cell constitute a first battery cell group, and the third battery cell and the fourth battery cell constitute a second battery cell group. The first battery cell group and the second battery cell group are distributed along a third direction, and the tab group of the third battery cell and the tab group of the fourth battery cell are respectively distributed along a second direction.

[0007] As one of the optional embodiments of this solution, the mounting part further includes a third mounting part and a fourth mounting part, the first mounting part and the second mounting part are connected to the same side of the connecting part, and the third mounting part and the fourth mounting part are connected to the same side of the connecting part away from the first mounting part and the second mounting part.

[0008] The protection section includes a third protection section and a fourth protection section. The third protection section is connected to the third mounting section, and the fourth protection section is connected to the fourth mounting section. The third mounting section and the third protection section cooperate to clamp the tab assembly of the third battery cell, and the fourth mounting section and the fourth protection section cooperate to clamp the tab assembly of the fourth battery cell.

[0009] As one of the optional embodiments of this solution, the connector further includes a second bend, one end of which is connected to the mounting portion and the other end of which is connected to the connecting portion.

[0010] As one of the optional embodiments of this solution, the surface of the tab assembly facing the mounting part is the connecting surface, the mounting part is connected to the connecting surface, the mounting part is electrically connected to the tab assembly, and the orthographic projection of the mounting part falls within the area enclosed by the connecting surface.

[0011] As one of the optional embodiments of this solution, the tab assembly has a first solder mark, and in the flattened state of the connector, the surface of the mounting part facing away from the tab assembly and / or the surface of the protective part facing away from the tab assembly has a second solder mark.

[0012] Along the thickness direction of the tab assembly, the second solder mark at least partially overlaps with the first solder mark.

[0013] As one of the optional embodiments of this solution, the end of the battery cell facing the mounting part has a first surface, and the edge of the second solder mark near the first surface has a bending gap D mm between it and the first surface, satisfying: 6.5mm≤D≤10mm.

[0014] As one optional embodiment of this solution, a single cell has a first direction and a second direction that intersect each other, and a third direction;

[0015] The tab assembly has a dimension H1 mm in the first direction and a dimension L1 mm in the second direction. There is a tab misalignment k mm between each tab in the tab assembly. The cell body has a dimension H mm in the third direction. The second solder mark has a dimension W1 mm ​​in the first direction satisfying: 3≤W1≤H1-HD. The second solder mark has a dimension L2 mm in the second direction satisfying: 10≤L2≤L1-2k.

[0016] As one of the optional embodiments of this solution, the single cell has a first direction. In the flattened state of the connector, the dimension of the mounting part in the first direction is a mm, and the dimension of the protective part in the first direction is h mm, satisfying: 3≤h≤a.

[0017] As one of the optional embodiments of this solution, the single cell has a second direction. In the folded state of the first bend, there is a distance S mm between the mounting part and the protective part. In the flattened state, the first bend has a dimension C1 mm in the second direction, satisfying: 2S≤C1≤5.

[0018] On the other hand, this application provides a battery pack including any of the single cells mentioned above.

[0019] One of the above technical solutions has the following advantages or beneficial effects:

[0020] The battery pack provided in this application incorporates a connector. The connecting portion of the connector is electrically connected to the terminal post, while the mounting portion and protective portion of the connector are electrically connected to the tab assembly. When the tab assembly is short or its length variation is small, the connector reduces the difficulty of connecting the tab assembly to the terminal post, improving the yield of electrical connections between the tab assembly and the terminal post in a single cell. By incorporating the connector, bending it during the connection of the terminal post and the tab assembly reduces the folding rate of the tab assembly and lowers the welding difficulty of thick tabs, effectively addressing the challenge of manufacturing thick cells. Furthermore, by including the protective portion, which, together with the mounting portion, clamps the tab assembly, direct contact between the welding head and the tab assembly is avoided during welding, thus protecting the tab assembly during welding. Attached Figure Description

[0021] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the overall structure of a single battery cell provided in Embodiment 1 of this application;

[0023] Figure 2 This is a schematic diagram of the battery cell structure provided in Embodiment 1 of this application;

[0024] Figure 3 This is a schematic diagram of the structure of the first solder mark in Embodiment 1 of this application;

[0025] Figure 4 This is a schematic diagram showing the connection relationship between the connector and the first electrode provided in Embodiment 1 of this application;

[0026] Figure 5 This is a schematic diagram of the connector provided in Embodiment 1 of this application;

[0027] Figure 6 This is a schematic diagram showing the positional relationship between the mounting part, the protection part, and the electrode assembly provided in Embodiment 1 of this application;

[0028] Figure 7 This is a schematic diagram of the structure of a single battery cell provided in Embodiment 2 of this application;

[0029] Figure 8 This is a flattened view of a single cell provided in Embodiment 2 of this application;

[0030] Figure 9 This is a schematic diagram of the connector provided in Embodiment 2 of this application.

[0031] Reference numerals: 1. Outer shell; 10. Battery cell; 11. Battery cell body; 12. Electrode assembly; 121. Connecting surface; 122. First solder mark; 13. First battery cell; 14. Second battery cell; 15. Third battery cell; 16. Fourth battery cell; 17. Outer surface; 18. Housing; 19. Housing cover; 2. Terminal post; 20. Connector; 21. Connecting part; 22. Mounting part; 221. First mounting part; 222. Second mounting part; 223. Third mounting part; 224. Fourth mounting part; 23. Protective part; 231. First protective part; 232. Second protective part; 233. Third protective part; 234. Fourth protective part; 24. Second bending part; 25. First bending part; 30. Second solder mark; 31. First surface; X, First direction; Y, Second direction; Z, Third direction. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0034] See Figures 1 to 6 This application provides a single battery cell and a battery pack. The single battery cell provided by this application includes a casing 1, a terminal post 2, and a battery cell 10. The terminal post 2 is disposed on the casing 1, that is, the terminal post 2 passes through the casing 1, with one end extending into the casing 1 and the other end extending into the outside of the casing 1. The battery cell 10 is housed in the casing 1 and includes a battery cell body 11 and a tab assembly 12 connected to one end of the battery cell body 11. The single battery cell also includes a connector 20, which includes a connecting portion 21, a mounting portion 22, a protective portion 23, and a first bending portion 25. The mounting portion 22 is connected to one side of the connecting portion 21; the protective portion 23 is connected to the side of the mounting portion 22 away from the connecting portion 21. The mounting portion 22 and the protective portion 23 are respectively disposed on opposite sides of the tab assembly 12 in the thickness direction. Along the thickness direction of the tab assembly 12, the tab assembly 12 is disposed between the mounting portion 22 and the protective portion 23. Both the mounting portion 22 and the protective portion 23 are electrically connected to the tab assembly 12, and the connecting portion 21 is electrically connected to the terminal post 2. The first bending portion 25 is located on the outside of the tab assembly 12 and is connected between the mounting portion 22 and the protective portion 23.

[0035] It should be noted that the mounting part 22 and the protective part 23 are arranged on opposite sides of the tab assembly 12, that is, the mounting part 22 and the protective part 23 are pressed against the tab assembly 12 in the thickness direction.

[0036] See Figure 2 It is understood that in this embodiment, the electrode assembly 12 is formed by stacking and welding multiple electrodes. The connector 20 is specifically a connector piece in this embodiment. The connector 20 is integrally formed with the connector 21, the protective part 23, the mounting part 22, and the first bending part 25. The protective part 23 and the mounting part 22 are fixed to the electrode assembly 12 by welding. The welding method can be ultrasonic welding, laser welding, or other welding methods, which are not limited here.

[0037] By providing a connector 20, the connecting portion 21 of the connector 20 is electrically connected to the terminal post 2, and the mounting portion 22 and the protective portion 23 of the connector 20 are electrically connected to the tab assembly 12. When the length of the tab assembly 12 is short, or the length dimension of the tab assembly 12 does not change significantly, the connector 20 can reduce the connection difficulty between the tab assembly 12 and the terminal post 2, and improve the yield of the electrical connection between the tab assembly 12 and the terminal post 2 in a single cell. In addition, by providing a first bending portion 25, the first bending portion 25 can be bent and cause the protective portion 23 to flip to the side of the tab assembly 12 away from the mounting portion 22. The protective portion 23 and the mounting portion 22 together clamp the tab assembly 12. When welding and fixing the protective portion 23, the mounting portion 22 and the tab assembly 12, the welding head can be prevented from directly contacting the tab assembly 12, thereby protecting the tab assembly 12 during welding.

[0038] Next Figures 1 to 5 The technical solution will be further explained using the illustrative embodiments shown in the figure as examples. Figure 1 The first direction X, the second direction Y, and the third direction Z shown in the diagram are intersecting. Preferably, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. It is understood that the first direction X, the second direction Y, and the third direction Z are not absolutely perpendicular, but can form a certain angle, which can be between 85° and 95°, and is not limited here. The battery cell 10 is a square battery cell. In this embodiment, the thickness direction of the battery cell 10 or the tab group 12 is the third direction Z, the length direction of the battery cell 10 is the second direction Y, and the height direction of the battery cell 10 is the first direction X.

[0039] It is understood that the electrode group 12 of the battery cell 10 includes a positive electrode group and a negative electrode group. The positive electrode group and the negative electrode group can be arranged on both sides of the battery cell 10 body along the first direction X, that is, a battery cell with electrode tabs on both sides; or they can be arranged on the same side of the battery cell 10 body along the first direction X, that is, a battery cell with electrode tabs on one side. The following is an example of the positive electrode group and the negative electrode group being arranged on both sides of the battery cell 10 body along the first direction X.

[0040] In this embodiment, the tab assembly 12 is connected to the end of the battery cell 10 body in the first direction X. The battery cell 10 includes a first battery cell 13 and a second battery cell 14 distributed along the third direction Z. The tab assemblies 12 of the first battery cell 13 and the second battery cell 14 are distributed along the second direction Y. In the second direction Y, the distance between the tab assemblies 12 of the first battery cell 13 and the second battery cell 14 is 2mm to 20mm, thereby minimizing overlap and interference between the tabs and affecting subsequent welding and assembly processes. The mounting part 22 has a size of 10mm to 30mm in the first direction X to ensure the normal overcurrent requirements of the battery cell. The mounting part 22 has a size of 30mm to 80mm in the second direction Y, thereby minimizing overlap and interference between the tabs and affecting subsequent welding and assembly processes.

[0041] Mounting part 22 includes a first mounting part 221 and a second mounting part 222. In the second direction Y, the first mounting part 221 and the second mounting part 222 are respectively connected to the two ends of the connecting part 21. The protective part 23 has a size of 15mm to 30mm in the second direction Y, thereby effectively protecting the tab assembly 12 during the welding process. The protective part 23 includes a first protective part 231 and a second protective part 232. Along the thickness direction of the tab assembly 12, the tab assembly 12 of the first battery cell 13 is disposed between the first protective part 231 and the first mounting part 221. The first protective part 231 and the first mounting part 221 cooperate to clamp the tab assembly 12 of the first battery cell 13. The tab assembly 12 of the second battery cell 14 is disposed between the second protective part 232 and the second mounting part 222. The second protective part 232 and the second mounting part 222 cooperate to clamp the tab assembly 12 of the second battery cell 14. There is a gap of i mm between the first mounting part 221 and the second mounting part 222, satisfying 0≤i≤20.

[0042] See Figure 2 and Figure 3 It is understood that the positive electrode tabs of the first battery cell 13 and the second battery cell 14 are both arranged on the same side along the first direction X, and the negative electrode tabs of the first battery cell 13 and the second battery cell 14 are both arranged on the side opposite to the positive electrode tabs along the first direction X. Two or more connectors 20 are provided, each connector 20 being used to connect the electrode tabs 12 of the same polarity on the first battery cell 13 and the second battery cell 14. In this embodiment, two connectors 20 are provided, one for connecting the positive electrode tabs of the first battery cell 13 and the second battery cell 14, and the other for connecting the negative electrode tabs of the first battery cell 13 and the second battery cell 14.

[0043] By setting a first cell 13 and a second cell 14 distributed along the third direction Z, the overall thickness design of the cell 10 can be improved, thereby increasing the capacity of the cell 10. By setting a connector 20 to connect the cell 10 and the pole post 2, one tab group 12 can be split into two when the thickness of the cell 10 is increased, and the two tab groups 12 of the same polarity are connected to the pole post 2 through the connector 20, which facilitates the bending of the tab group 12 and reduces the difficulty of a single welding. The first protection part 231 and the second protection part 232 can protect the tab group 12 of the same polarity, and minimize the damage to the tab group 12 during the welding process, so as to achieve a better connection effect.

[0044] See Figures 7 to 9 The following explanation will be based on the example where both the positive and negative tabs are located on the same side of the cell body 11 along the first direction.

[0045] In addition to the first battery cell 13 and the second battery cell 14, the battery cell 10 also includes a third battery cell 15 and a fourth battery cell 16 distributed along the third direction Z. The first battery cell 13, the second battery cell 14, the third battery cell 15, and the fourth battery cell 16 are all stacked along the third direction Z. The first battery cell 13 and the second battery cell 14 constitute a first battery cell group, and the third battery cell 15 and the fourth battery cell 16 constitute a second battery cell group. The first battery cell group and the second battery cell group are distributed along the third direction Z. The tab group 12 of the third battery cell 15 and the tab group 12 of the fourth battery cell 16 are respectively distributed along the second direction Y. That is, the positive tab group and the negative tab group of the third battery cell 15 are distributed at intervals along the second direction Y on the same side of the third battery cell 15, and the positive tab group and the negative tab group 12 of the fourth battery cell 16 are distributed at intervals along the second direction Y on the same side of the fourth battery cell 16. There are two connectors 20, one of which is used to connect the positive tabs of the first battery cell 13, the second battery cell 14, the third battery cell 15 and the fourth battery cell 16, and the other is used to connect the negative tabs of the first battery cell 13, the second battery cell 14, the third battery cell 15 and the fourth battery cell 16.

[0046] Specifically, the mounting part 22 also includes a third mounting part 223 and a fourth mounting part 224. The first mounting part 221 and the second mounting part 222 are connected to the same side of the connecting part 21. The third mounting part 223 and the fourth mounting part 224 are connected to the same side of the connecting part 21 away from the first mounting part 221 and the second mounting part 222. The protection part 23 includes a third protection part 233 and a fourth protection part 234. The third mounting part 223 and the third protection part 233 cooperate to clamp the tab group 12 of the third battery cell 15. The fourth mounting part 224 and the fourth protection part 234 cooperate to clamp the tab group 12 of the fourth battery cell 16.

[0047] By setting the third cell 15 and the fourth cell 16 on the connector 20, the stacking and connection of four sets of cells 10 can be realized, thereby further increasing the capacity of a single battery. By setting the third mounting part 223, the fourth mounting part 224, the third protection part 233, and the fourth protection part 234, the length of the tab group 12 can be increased without increasing the thickness and capacity of the cell 10, making it easier to bend the tab group 12 and electrically connect it to the terminal post 2.

[0048] Furthermore, the connectors 20 used in both types of battery cells 10 include a second bend 24. One end of the second bend 24 is connected to the mounting portion 22, and the other end is connected to the connecting portion 21. Multiple second bends 24 are provided. In some embodiments, two second bends 24 may be provided, one connected to the first mounting portion 221 and the other to the second mounting portion 222. In another embodiment, four second bends 24 may be provided, with one second bend 24 connected between the connecting portion 21 and the first mounting portion 221, between the connecting portion 21 and the second mounting portion 222, between the connecting portion 21 and the third mounting portion 223, and between the connecting portion 21 and the fourth mounting portion 224. The number of second bends 24 is related to the pairs of mounting portions 22 and connecting portions 23, with one second bend 24 corresponding to a pair of mounting portions 22 and connecting portions 23.

[0049] By providing the second bending portion 24, it is easy to bend between the mounting portion 22 and the connecting portion 21, thereby enabling the connector 20 to make full use of the space inside the housing 1 and to connect the pole post 2 and the tab assembly 12 without increasing the height of the housing 1.

[0050] See Figure 5 In the flattened state of the connector 20, the dimension c mm of the second bent portion 24 in the first direction X satisfies: 2 ≤ c ≤ 5; the dimension e mm of the second bent portion 24 in the second direction Y satisfies:

[0051] 10≤e≤30. It can be understood that when the dimensions c mm and e mm simultaneously satisfy 2≤c≤5 and 10≤e≤30, the connector 20 and the tab group 12 have a good connection bending effect and the individual battery has a good overcurrent effect.

[0052] See Figure 5 One end of the first bending portion 25 is connected to the mounting portion 22, and the other end is connected to the protection portion 23. Multiple first bending portions 25 are provided. In some embodiments, such as a scheme where two battery cells 10 overlap, two first bending portions 25 may be provided, one connected between the first mounting portion 221 and the first protection portion 231, and the other connected between the second mounting portion 222 and the second protection portion 232.

[0053] See Figure 9In another embodiment, such as a scheme where four battery cells 10 are stacked, four first bending portions 25 can be provided, namely, one first bending portion 25 is provided between the first mounting portion 221 and the first protective portion 231, between the second mounting portion 222 and the second protective portion 232, between the third mounting portion 223 and the third protective portion 233, and between the fourth mounting portion 224 and the fourth protective portion 234. By providing the first bending portions 25, the protective portion 23 can be flipped relative to the mounting portion 22, and the protective portion 23 and the mounting portion 22 can be stacked to clamp the tab assembly 12, which helps to protect the tab assembly 12.

[0054] It is understandable that the connection method between the first battery cell 13 and the second battery cell 14 and the connector 20 is the same as the connection method between the third battery cell 15 and the fourth battery cell 16 and the connector 20. The following explanation uses one of these methods as an example. (See reference...) Figure 4 The surface of the tab assembly 12 facing the mounting portion 22 is a connecting surface 121. The mounting portion 22 is connected to the connecting surface 121 and is electrically connected to the tab assembly 12. The orthographic projection of the mounting portion 22 falls within the area enclosed by the connecting surface 121. In other words, the tab assembly 12 covers the corresponding mounting portion 22. This prevents any excess portion of the mounting portion 22 from extending beyond the tab assembly 12, minimizing wrinkles or stacking of excess portion 22 within the housing 1, which could interfere with the bending of the connecting portion 21 and thus ensure the bending effect of the connector 20. In this embodiment, the mounting portion 22 has a dimension a mm in the first direction X, satisfying 5 ≤ a ≤ 10, and a dimension b mm in the second direction Y, satisfying 15 ≤ b ≤ 30. Under these dimensional constraints, the dimensions of the mounting portion 22 meet the current requirements for the soldering area of ​​most battery cells, thus fulfilling the current requirements of the battery cell.

[0055] See Figure 3 and Figure 4 The tab assembly 12 has a first weld mark 122, and the tabs of the tab assembly 12 are connected by welding. During the welding process, the first weld mark 122 is formed on the surface of the tab assembly 12. The connector 20 has a second weld mark 30. In the flattened state, the connector 20 is fixed to the tab assembly 12 by welding, and the second weld mark 30 is formed on the surface of the connector 20. Specifically, the second weld mark 30 can exist on the surface of the mounting part 22 opposite to the tab assembly 12, or it can exist on the surface of the protective part 23 opposite to the tab assembly 12. The second weld mark 30 can also exist on both the surface of the mounting part 22 opposite to the tab assembly 12 and the surface of the protective part 23 opposite to the tab assembly 12.

[0056] Along the thickness direction of the tab assembly 12, the second solder mark 30 is at least partially overlapped with the first solder mark 122.

[0057] Multiple electrodes are welded into an electrode assembly 12, and a first weld mark 122 is formed on the surface of the electrode assembly 12. The connector 20 is then connected to the electrode assembly 12 by welding, and a second weld mark 30 is formed on the connector 20. Furthermore, since the first weld mark 122 and the second weld mark 30 at least partially overlap, the welding between the electrodes is strengthened when welding the connector 20 to the electrode assembly 12, contributing to a better welding effect.

[0058] See Figure 4 The battery cell 10 has a first surface 31 on the side facing the mounting portion 22. The edge of the second solder mark 30 near the first surface 31 has a bending gap D mm: 6.5 ≤ D ≤ 10. By setting the bending gap, after the connector 20 is welded to the tab assembly 12, it is convenient to bend the welded connector 20 and tab assembly 12 to facilitate the connection between the tab assembly 12 and the pole post 2.

[0059] Please see Figures 1 to 5 ,by Figures 1 to 5Taking the provided single-cell battery as an example, the outer casing 1 includes a housing 18 and a cover 19. The cover 19 is fixedly installed at both ends of the housing 18. The terminal post 2 passes through the cover 19, with one end of the terminal post 2 extending into the housing 18 and the other end exposed outside the housing 18. Furthermore, the tab group 12 of the first cell 13 is referred to as the first tab group, and the tab group 12 of the second cell 14 is referred to as the second tab group. During the assembly process of the single-cell battery, the tabs of the first cell 13 are welded to form the first tab group, and the tabs of the second cell 14 are welded to form the second tab group. Next, align the first mounting part 221 of a connector 20 with the first electrode lug, and align the second mounting part 222 with the second electrode lug. Then, fold the first bending part 25 so that the first bending part 25 between the first protective part 231 and the first mounting part 221 bends, and the first protective part 231 flips to the side of the first electrode lug 12 away from the first mounting part 221. The first protective part 231 and the first mounting part 221 together clamp the first electrode lug. Then, weld and fix the first mounting part 221, the first electrode lug, and the first protective part 231. The first bend 25 between the second protective part 232 and the second mounting part 222 is folded over, causing the second protective part 232 to flip to the side of the second electrode assembly away from the second mounting part 222. The second protective part 232 and the second mounting part 222 together clamp the second electrode assembly. Then, the second mounting part 222, the second electrode assembly, and the second protective part 232 are welded and fixed. Then, the connecting part 21 is welded and fixed to the pole post 2, so that the first battery cell 13 and the second battery cell 14 are electrically connected to the pole post 2. Then, the cover 19 is fixed to the housing 18 by welding. During the welding and fixing process of the cover 19, the second bend 24 is bent, so that the extension direction of the connecting part 21 changes relative to the mounting part 22. This reduces the connection difficulty between the pole post 2 and the electrode assembly 12 when the length of the electrode assembly 12 is short or the increase in length is not significant, and realizes the electrical connection between the electrode assembly 12 and the pole post 2.

[0060] The performance of the parameters provided in the embodiments of this application will be evaluated below with reference to specific examples.

[0061] Examples 1 to 5 are provided, each example being used to statistically analyze 1000 individual cells. In Examples 1 to 5, the bending gap D is a variable, while other parameters are constants. For example, the second solder mark 30 has a dimension W1 = 5 mm in the first direction X and a dimension L2 = 15 mm in the second direction Y. The protective part 23 has a dimension h = 8 mm in the first direction X, and the first bending part 25 has a dimension C1 = 3 mm in the second direction Y. Examples 1 to 3 satisfy 6.5 ≤ D ≤ 10, while Examples 4 and 5 do not satisfy 6.5 ≤ D ≤ 10. Specific parameters and test results are detailed in Table 1.

[0062] Table 1

[0063] project D mm Electrode group cracking rate % Electron group morphology Example 1 6.5 0.30 good Example 2 8 0.20 better Example 3 10 0.10 generally Example 4 5 0.50 very good Example 5 12 0.05 Difference

[0064] In this application, the evaluation criteria for the morphology of the tab assembly are defined as follows: After the assembly and welding are completed, the individual cells are subjected to CT scanning or cross-sectional observation. If: the curve of the tab assembly 12 is smooth and there are no wrinkles, it is considered very good; the curve of the tab assembly 12 is smooth and there are almost no wrinkles, it is considered good; the curve of the tab assembly 12 is smooth and there are few wrinkles, it is considered good; the curve of the tab assembly 12 is smooth and there are many wrinkles, it is considered average; and the curve of the tab assembly 12 is not smooth and there are many wrinkles, it is considered poor. The tab assembly cracking rate (%) = (number of cracked tab assemblies) / (individual cell * number of tab assemblies in individual cell) * 100%. Therefore, in the above embodiments 1-5, when D satisfies 6.5 ≤ D ≤ 10, the tab assembly 12 has a low cracking rate and a good morphology to ensure the folding effect of the tab assembly 12. When D is not 6.5 ≤ D ≤ 10, the morphology deteriorates to varying degrees.

[0065] The tab assembly 12 has a dimension H1 mm in the first direction X and a dimension L1 mm in the second direction Y. There is a tab misalignment k mm between the tabs in the tab assembly 12. The cell body 10 has a dimension H mm in the third direction Z. The second solder mark 30 has a dimension W1 mm ​​in the first direction X satisfying: 3 ≤ W1 ≤ H1 - HD. The second solder mark 30 has a dimension L2 mm in the second direction Y satisfying: 10 ≤ L2 ≤ L1 - 2k. Specifically, in this embodiment, W1 mm ​​satisfies: 3 ≤ W1 ≤ 7, and L2 mm satisfies: 10 ≤ L2 ≤ 20. It is understood that the tab misalignment k varies depending on the manufacturing process capability and tab thickness. The tab misalignment can be measured manually or by a CCD camera. The calculation of the tab misalignment k is prior art and will not be elaborated here. The following section evaluates the performance of the parameters provided in the embodiments of this application in conjunction with specific examples.

[0066] Examples 6 to 10 are provided, each example for statistical analysis of 1000 individual battery cells. In examples 6 to 10, the dimensions W1 of the second solder mark 30 in the first direction X and L2 of the second solder mark 30 in the second direction Y are variables, while other parameters are constants. For example, the bending gap D between the edge of the second solder mark 30 near the first surface 31 and the first surface 31 is 8mm, the dimension h of the protective part 23 in the first direction X is 8mm, the cell body 11 has a dimension H = 10mm in the third direction Z, the dimension C1 of the first bent part 25 in the second direction Y is 3mm, and the tab misalignment k = 1mm. Based on 3≤W1≤H1-HD and 10≤L2≤L1-2k, the above parameters have the following corresponding relationships. Examples 6 to 8 satisfy 10≤L2≤20 and 3≤W1≤7, while examples 9 and 10 do not satisfy 10≤L2≤20 and 3≤W1≤7. Specific parameters and test results are detailed in Table 2.

[0067] Table 2

[0068]

[0069] It is understandable that the welding difficulty is inversely proportional to the value of W1*L2, that is, the larger the area of ​​the second weld mark 30, the greater the welding difficulty. Therefore, in embodiments 6 to 10 above, when W1 mm ​​satisfies: 3≤W1≤7 and L2 mm satisfies: 10≤L2≤20, the second weld mark 30 has a smaller internal resistance and is less difficult to weld, resulting in a good connection between the tab assembly 12 and the mounting portion 22 of the connector 20; however, outside these ranges, the welding difficulty increases.

[0070] When the connector 20 is in its flattened state, the mounting part 22 has a dimension of a mm in the first direction X, and the protective part 23 has a dimension of h mm in the first direction X, satisfying: 3 ≤ h ≤ a. Specifically, the dimension h mm of the protective part 23 in the first direction X satisfies: 5 ≤ h ≤ 10.

[0071] It should be noted that the size of 'a' also needs to be considered. For example, when the side of the mounting part 22 near the cover 19 is flush with the side of the tab assembly 12 near the cover 19, 'a' should be smaller than the size H1 of the tab in the first direction X, so as to prevent the connector 20 from coming into contact with the cell body 11, which could lead to ineffective welding or short circuits. It should also be considered that the size of 'a' should not be too large, so that the connector 20 is not convenient to be placed inside the outer casing 1.

[0072] When the first bent portion 25 is in the folded state, there is a distance S mm between the mounting portion 22 and the protective portion 23. When the connector 20 is in the flattened state, the first bent portion 25 has a dimension C1 mm in the second direction Y, which satisfies: 2S≤C1≤5. Specifically, in this embodiment, the dimension C1 mm of the first bent portion 25 in the second direction Y satisfies: 2≤C1≤5.

[0073] Examples 11 to 15 are provided, each example being used to statistically analyze 1000 individual cells. In examples 11 to 15, the dimensions of the protective part 23 in the first direction X (h) and the dimensions of the first bent part 25 in the second direction Y (C1) are variables, while other parameters are constants. For example, the bending gap D between the edge of the second solder mark 30 near the first surface 31 and the first surface 31 is 8mm, the dimensions of the second solder mark 30 in the first direction X (W1) are 5mm, and the dimensions in the second direction Y (L2) are 15mm. Examples 11 to 13 satisfy 5≤h≤10 and 2≤C1≤5, while examples 14 and 15 do not satisfy 5≤h≤10 and 2≤C1≤5. Specific parameters and test results are detailed in Table 3.

[0074] Table 3

[0075] project h mm <![CDATA[C1mm]]> Electrode group cracking rate % Bending effect Example 11 5 2 0.20 Poor Example 12 8 3 0.10 generally Example 13 10 5 0.50 better Example 14 3 1 0.30 Difference Example 15 12 7 0.05 good

[0076] It is understandable that the tab assembly cracking rate (%) = (number of cracked tab assemblies) / (single cell * number of tab assemblies in a single cell) * 100%. The bending effect is positively correlated with the value of C1. The larger C1 is, the better the bending effect, and the smaller the deformation of the protective part 23 at the bending point. The larger the deformation at the bending point, the more difficult the bending becomes. Therefore, in the above embodiments 11 to 15, when h satisfies: 5 ≤ h ≤ 10 and C1 satisfies: 2 ≤ C1 ≤ 5, the tab assembly 12 has a low cracking rate, and the protective part 23 has a good bending effect, thus achieving a good protective effect on the tab assembly 12; if it is outside the above range, the bending effect deteriorates, and it cannot effectively protect the tab assembly 12.

[0077] Furthermore, this application also provides a battery pack, which includes the aforementioned single battery cell. The battery pack provided by this application, by providing a connector 20, wherein the connecting portion 21 of the connector 20 is electrically connected to the terminal post 2, and the mounting portion 22 and the protection portion 23 of the connector 20 are electrically connected to the tab assembly 12, can reduce the connection difficulty between the tab assembly 12 and the terminal post 2 when the length of the tab assembly 12 is short or the length variation of the tab assembly 12 is not significant, thereby improving the yield of the electrical connection between the tab assembly 12 and the terminal post 2 in the single battery cell. By providing the connector 20, bending the connector 20 when connecting the terminal post 2 and the tab assembly 12 can reduce the folding rate of the tab assembly 12, solving the problem of high welding difficulty for thick tabs. Furthermore, by providing a protective part 23, which together with the mounting part 22 clamps the tab assembly 12, the welding head can be prevented from directly contacting the tab assembly 12 when welding and fixing the protective part 23, the mounting part 22 and the tab assembly 12, thereby protecting the tab assembly 12 during welding.

[0078] The above description is only a partial implementation of the embodiments of this application and is not intended to limit the application in any way. The protection scope of the embodiments of this application is not limited thereto. Any simple modifications, equivalent changes and alterations that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A single-cell battery, characterized in that, include: Outer shell (1); The pole post (2) is disposed on the outer casing (1); A battery cell (10) is housed in the outer casing (1). The battery cell (10) includes a battery cell body (11) and a tab assembly (12) connected to one end of the battery cell body (11). The connector (20) includes a connecting part (21), a mounting part (22), a protective part (23), and a first bending part (25); the mounting part (22) is connected to one side of the connecting part (21); the protective part (23) is connected to the side of the mounting part (22) away from the connecting part (21); the mounting part (22) and the protective part (23) are respectively disposed on opposite sides of the electrode assembly (12) in the thickness direction; along the thickness direction of the electrode assembly (12), the electrode assembly (12) is disposed between the mounting part (22) and the protective part (23); both the mounting part (22) and the protective part (23) are electrically connected to the electrode assembly (12); and the connecting part (21) is electrically connected to the pole post (2). The first bending portion (25) is located on the outside of the tab assembly (12), and the first bending portion (25) is connected between the mounting portion (22) and the protective portion (23).

2. The single-cell battery according to claim 1, characterized in that, The individual battery cell has a first direction (X), a second direction (Y), and a third direction (Z) that intersect each other in pairs; The tab group (12) is connected to the end of the cell body (11) in the first direction (X); the cell (10) includes a first cell (13) and a second cell (14) distributed along the third direction (Z), and the tab group (12) of the first cell (13) and the tab group (12) of the second cell (14) are distributed along the second direction (Y); The mounting part (22) includes a first mounting part (221) and a second mounting part (222). Along the second direction (Y), the first mounting part (221) and the second mounting part (222) are respectively connected to both ends of the connecting part (21). The protection part (23) includes a first protection part (231) and a second protection part (232). Along the thickness direction of the tab group (12), the tab group (12) of the first cell (13) is disposed between the first protection part (231) and the first mounting part (221), and the tab group (12) of the second cell (14) is disposed between the second protection part (232) and the second mounting part (222).

3. The single-cell battery according to claim 2, characterized in that, The battery cell (10) further includes a third battery cell (15) and a fourth battery cell (16) distributed along a third direction (Z). The first battery cell (13) and the second battery cell (14) constitute a first battery cell group, and the third battery cell (15) and the fourth battery cell (16) constitute a second battery cell group. The first battery cell group and the second battery cell group are distributed along the third direction (Z). The tab group (12) of the third battery cell (15) and the tab group (12) of the fourth battery cell (16) are respectively distributed along the second direction (Y). The mounting portion (22) further includes a third mounting portion (223) and a fourth mounting portion (224), wherein the first mounting portion (221) and the second mounting portion (222) are connected to the same side of the connecting portion (21), and the third mounting portion (223) and the fourth mounting portion (224) are connected to the same side of the connecting portion (21) away from the first mounting portion (221) and the second mounting portion (222); The protection part (23) includes a third protection part (233) and a fourth protection part (234). The third protection part (233) is connected to the third mounting part (223), and the fourth protection part (234) is connected to the fourth mounting part (224). The third mounting part (223) and the third protection part (233) cooperate to clamp the tab group (12) of the third battery cell (15), and the fourth mounting part (224) and the fourth protection part (234) cooperate to clamp the tab group (12) of the fourth battery cell (16).

4. The single-cell battery as described in claim 1, characterized in that, The connector (20) further includes a second bend (24), one end of which is connected to the mounting part (22) and the other end is connected to the connecting part (21).

5. The single-cell battery as described in claim 1, characterized in that, The surface of the tab assembly (12) facing the mounting part (22) is a connecting surface (121). The mounting part (22) is connected to the connecting surface (121). The mounting part (22) is electrically connected to the tab assembly (12). The orthographic projection of the mounting part (22) falls within the area enclosed by the connecting surface (121).

6. The single-cell battery as described in claim 1, characterized in that, The tab assembly (12) has a first solder mark (122), and in the flattened state of the connector (20), the mounting part (22) has a second solder mark (30) on the surface opposite to the tab assembly (12) and / or the protective part (23) has a second solder mark (30) on the surface opposite to the tab assembly (12). Along the thickness direction of the tab assembly (12), at least a portion of the second solder mark (30) overlaps with the first solder mark (122).

7. The single-cell battery as described in claim 6, characterized in that, The battery cell (10) has a first surface (31) at one end facing the mounting part (22), and the second solder mark (30) has a bending gap D mm between the edge of the second solder mark (31) and the first surface (31), satisfying: 6.5mm≤D≤10mm.

8. The single-cell battery as described in claim 7, characterized in that, The individual battery cell has a first direction (X), a second direction (Y), and a third direction (Z) that intersect each other in pairs; The tab group (12) has a dimension H1 mm in the first direction (X) and a dimension L1 mm in the second direction (Y). There is a tab misalignment k mm between each tab in the tab group (12). The cell body (11) has a dimension H mm in the third direction (Z). The second solder mark (30) has a dimension W1 mm ​​in the first direction (X) satisfying: 3≤W1≤H1-HD. The second solder mark (30) has a dimension L2 mm in the second direction (Y) satisfying: 10≤L2≤L1-2k.

9. The single-cell battery as described in claim 1, characterized in that, The single cell has a first direction (X). In the flattened state of the connector (20), the size of the mounting part (22) in the first direction (X) is a mm, and the size of the protective part (23) in the first direction (X) is h mm, satisfying: 3≤h≤a.

10. The single-cell battery as described in claim 1, characterized in that, The single cell has a second direction (Y). In the folded state of the first bending portion (25), there is a distance S mm between the mounting portion (22) and the protective portion (23). In the flattened state of the connector (20), the first bending portion (25) has a dimension C1 mm in the second direction (Y) that satisfies: 2S≤C1≤5.

11. A battery pack, characterized in that, Includes the single-cell battery as described in any one of claims 1-10.

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