Battery cell, battery, and electric device

Abstract

A battery cell (6), a battery (2), and an electric device. The battery cell (6) includes an electrode assembly (10), a case (20), a positive electrode terminal (30), and a negative electrode terminal (40). The case (20) includes a first wall portion (20a). The electrode assembly (10) is housed in the case (20), and includes a positive electrode tab (12) and a negative electrode tab (13). The positive electrode terminal (30) is provided to the first wall portion (20a) and is electrically connected to the positive electrode tab (12), and includes a first positive electrode terminal portion (31) located outside the first wall portion (20a). The negative electrode terminal (40) is provided to the case (20) and is electrically connected to the negative electrode tab (13), and includes a first negative electrode terminal portion (41) located outside the case (20). A projected area of the first positive electrode terminal portion (31) in a thickness direction thereof is larger than a projected area of the first negative electrode terminal portion (41) in a thickness direction thereof.

Description

Battery cells, batteries and electrical devices Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery, and an electrical device. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery technology, improving the cycle performance of individual battery cells is a key research direction.

[0004] Summary of the Invention

[0005] This application provides a battery cell, a battery, and an electrical device that can improve cycle performance.

[0006] In a first aspect, embodiments of this application provide a battery cell, which includes an electrode assembly, a housing, a positive terminal, and a negative terminal. The housing includes a first wall. The electrode assembly is housed within the housing and includes a positive electrode tab and a negative electrode tab. The positive terminal is disposed on the first wall and electrically connected to the positive electrode tab, and the positive terminal includes a first positive terminal portion located outside the first wall. The negative terminal is disposed on the housing and electrically connected to the negative electrode tab, and the negative terminal includes a first negative terminal portion located outside the housing. The projected area of ​​the first positive terminal portion along its thickness direction is larger than the projected area of ​​the first negative terminal portion along its thickness direction.

[0007] During the cycling process of a single battery cell, the positive and negative electrode tabs generate heat when current flows through them. Some of the heat from the positive electrode tab can be dissipated outwards via the first positive terminal, and some of the heat from the negative electrode tab can be dissipated outwards via the first negative terminal, thereby reducing the temperature rise of both the positive and negative electrode tabs. In this embodiment, the projected area of ​​the first positive terminal along its thickness direction is larger than that of the first negative terminal along its thickness direction. This allows the first positive terminal to have a larger exposed area, thereby improving the efficiency of heat dissipation from the first positive terminal, reducing the heat accumulated on the positive electrode tab, reducing the temperature difference between the positive and negative electrode tabs, and improving the cycle performance and cycle life of the single battery cell.

[0008] In some embodiments, the first positive terminal is used to connect to the first busbar of the battery and exchange heat with the heat exchanger of the battery. The first positive terminal can exchange heat with the heat exchanger, thereby further reducing the temperature rise of the positive electrode tab, reducing the temperature difference between the positive and negative electrode tabs, improving the heat dissipation capacity of the battery cell, improving the cycle performance and cycle life of the battery cell, and reducing the risk of thermal runaway during fast charging. In some embodiments, the first positive terminal includes a first part and a second part, the first part being used to connect to the first busbar, and the second part being used to exchange heat with the heat exchanger. The first busbar and the heat exchanger act on different parts of the first positive terminal, thus reducing the risk of interference between the first busbar and the heat exchanger.

[0009] In some embodiments, the first portion is configured to at least partially overlap and connect with the first busbar in the thickness direction of the first wall, and the second portion is configured to at least partially overlap with the heat exchanger in the thickness direction of the first wall. The first portion and the first busbar being arranged along the thickness direction can increase the connection strength and flow area between them, reducing heat generation. The second portion and the heat exchanger being arranged along the thickness direction can increase the heat exchange area between them, improving heat exchange efficiency. The first busbar and the heat exchanger can share space in the thickness direction, thereby improving space utilization in the thickness direction and increasing the battery's energy density.

[0010] In some embodiments, the thickness of the first portion is greater than the thickness of the second portion. The larger thickness of the first portion compared to the second portion makes it less prone to melting during welding to the first busbar component, thereby improving the reliability of the battery cell. The second portion does not need to be welded to the first busbar component and can have a smaller thickness, thereby reducing the volume and weight of the positive terminal and increasing the energy density of the battery cell.

[0011] In some embodiments, the first portion extends beyond the second portion in a direction away from the first wall. In the thickness direction of the first wall, the surface of the second portion away from the first wall is closer to the first wall than the surface of the second portion away from the first wall, thereby reserving more space on the side of the second portion away from the first wall to facilitate the arrangement of heat exchange components and improve space utilization.

[0012] In some embodiments, the first positive terminal portion has a first recess on the side away from the first wall portion, and the second portion is the bottom wall of the first recess. By providing the first recess, the volume and weight of the first positive terminal portion can be reduced, and the exposed area of ​​the first positive terminal portion can be increased, thereby improving the heat dissipation capacity of the first positive terminal portion. By providing the first recess, space can also be provided for the heat exchanger, improving the space utilization rate in the thickness direction of the first wall portion.

[0013] In some embodiments, the depth of the first recess is 0.1 mm to 2 mm in the thickness direction of the first wall portion. Limiting the depth of the first recess to greater than or equal to 0.1 mm provides more space for other components (e.g., heat exchangers), improving space utilization. Limiting the depth of the first recess to less than or equal to 2 mm can reduce the loss of thermal conductivity caused by the thinning of the second portion, thus balancing the heat exchange efficiency of the second portion and the heat exchanger to some extent.

[0014] In some embodiments, the first portion and the second portion are disposed along a first direction, and the dimension of the first portion along the second direction is smaller than the dimension of the second portion along the second direction. The thickness direction of the first wall, the first direction, and the second direction are all perpendicular to each other. The second portion has a larger dimension in the second direction, which increases the heat dissipation area of ​​the second portion, reduces the temperature rise of the positive terminal and the positive electrode tab, and improves the cycle performance of the battery cell. The thickness of the second portion is smaller, so increasing the dimension of the second portion along the second direction has a smaller impact on the energy density of the battery cell compared to increasing the dimension of the first portion along the second direction.

[0015] In some embodiments, the first portion and the second portion are spaced apart along a first direction, which is perpendicular to the thickness direction of the first wall portion. The first portion and the second portion can be formed independently, which is beneficial for the processing and forming of the part, and can also overcome the size limitations caused by manufacturing capacity constraints, providing a second portion with a larger area, thereby improving the heat dissipation effect.

[0016] In some embodiments, the first portion and the second portion are disposed along a first direction, which is perpendicular to the thickness direction of the first wall portion. In this first direction, the size of the second portion is larger than the size of the first portion. Having a larger size in the first direction increases the heat exchange area between the second portion and the heat exchanger, improving heat exchange efficiency, reducing the internal temperature rise of the battery cell, and improving the cycle performance of the battery cell. The second portion also has a smaller thickness, so increasing the size of the second portion has a smaller impact on the weight of the battery cell compared to increasing the size of the first portion.

[0017] In some embodiments, the surface of the first positive terminal portion away from the first wall portion is configured to connect with the heat exchanger.

[0018] In some embodiments, the surface of the first positive terminal portion away from the first wall portion includes a first region and a second region. The first region is configured to overlap and connect with the first busbar component in the thickness direction of the first wall portion, and the second region is configured to overlap with the heat exchanger in the thickness direction of the first wall portion. The first busbar component and the heat exchanger act on the first region and the second region respectively, which can reduce the risk of interference between the first busbar component and the heat exchanger, reduce the superposition of the first busbar component and the heat exchanger in the thickness direction, and improve space utilization.

[0019] In some embodiments, the first region and the second region are spaced apart to reduce the risk of interference between the first busbar and the heat exchanger due to assembly errors.

[0020] In some embodiments, the area of ​​the second region is larger than the area of ​​the first region. A larger area in the second region can improve the heat exchange efficiency between the heat exchanger and the first positive terminal, reduce the temperature rise of the first positive terminal, and improve the cycle performance and reliability of the battery cell.

[0021] In some embodiments, the ratio of the area of ​​the first region to the projected area of ​​the first positive terminal portion along the thickness direction of the first wall portion is greater than or equal to 1.5%, thereby providing a larger connection area and higher connection strength between the first positive terminal portion and the first busbar component, improving the flow capacity between the first positive terminal portion and the first busbar component, reducing heat generation, and lowering the temperature rise.

[0022] In some embodiments, the ratio of the area of ​​the second region to the projected area of ​​the first positive terminal portion along the thickness direction of the first wall portion is greater than or equal to 10%, thereby providing a larger heat exchange area between the first positive terminal portion and the heat exchanger, improving the heat exchange efficiency between the first positive terminal portion and the heat exchanger, reducing the temperature rise of the first positive terminal portion and the temperature rise of the electrode assembly, and improving the cycle performance of the battery cell.

[0023] In some embodiments, the first wall portion is provided with a positive electrode lead-out hole. The positive terminal also includes a second positive terminal portion and a third positive terminal portion. The second positive terminal portion is located inside the first wall portion and electrically connected to the positive electrode tab. At least a portion of the third positive terminal portion is accommodated in the positive electrode lead-out hole, and the third positive terminal portion connects the second positive terminal portion and the first positive terminal portion. In the thickness direction of the first wall portion, a portion of the first wall portion is located between the first positive terminal portion and the second positive terminal portion.

[0024] In some embodiments, the second positive terminal and the third positive terminal are integrally formed, which can improve the connection strength between the second positive terminal and the third positive terminal, reduce resistance, and improve overcurrent capability.

[0025] In some embodiments, the first positive terminal portion is provided with a first through hole, which extends through the first positive terminal portion along the thickness direction of the first wall portion. A portion of the third positive terminal portion is accommodated in the first through hole and connected to the first positive terminal portion.

[0026] In some embodiments, in the thickness direction of the first wall portion, the end of the third positive terminal portion away from the second positive terminal portion does not extend beyond the first through hole, thereby reducing the risk of the third positive terminal portion interfering with the connection between the first positive terminal portion and other components.

[0027] In some embodiments, the first positive terminal is configured such that it at least partially overlaps with the heat exchanger of the battery in the thickness direction of the first wall. The third positive terminal is configured such that it does not overlap with the heat exchanger in the thickness direction of the first wall. By avoiding direct contact between the third positive terminal and the heat exchanger, the risk of interference between them can be reduced, and the flatness of the heat exchange interface between the first positive terminal and the heat exchanger can be improved.

[0028] In some embodiments, the first positive terminal portion includes a first edge and a second edge disposed opposite to each other along a first direction, the first direction being parallel to the length direction of the first wall portion. In the first direction, the minimum distance between the axis of the first through hole and the first edge is equal to the minimum distance between the axis of the first through hole and the second edge. Centrally positioning the first through hole and the third positive terminal portion can improve the structural strength of the positive terminal and reduce the risk of deformation of the first positive terminal portion.

[0029] In some embodiments, in a first direction, the minimum distance between the axis of the first through-hole and the first edge is less than the minimum distance between the axis of the first through-hole and the second edge. The portion of the first positive terminal located between the first edge and the first through-hole is used to connect with the first busbar component of the battery, and the portion of the first positive terminal located between the second edge and the first through-hole is used for heat exchange with the heat exchange component of the battery. The eccentric design of the first through-hole allows for a larger area to exchange heat with the heat exchange component, thereby improving heat exchange efficiency. Embodiments of this application can also reduce the distance between the third positive terminal and the first busbar component, shortening the conductive path, reducing resistance, and reducing heat generation.

[0030] In some embodiments, the positive terminal includes a plurality of third positive terminal portions spaced apart. By providing a plurality of third positive terminal portions, the flow capacity can be improved, heat generation can be reduced, the structural strength of the positive terminal can be increased, and the stability of the connection between the positive terminal and the first wall portion can be enhanced.

[0031] In some embodiments, the first positive terminal portion includes a first portion and a second portion spaced apart along a first direction, the first direction being perpendicular to the thickness direction of the first wall portion. The first portion is connected to the second positive terminal portion via at least one third positive terminal portion, and the second portion is connected to the second positive terminal portion via at least one third positive terminal portion. The two third positive terminal portions can respectively fix the first portion and the second portion to the first wall portion to maintain a fixed relative position between the first portion and the second portion.

[0032] In some embodiments, the first positive terminal portion includes a first edge and a second edge disposed opposite to each other along a first direction, the first direction being parallel to the length direction of the first wall portion. The first positive terminal portion has two first through holes spaced apart along the first direction, and two third positive terminal portions respectively pass through the two first through holes and are connected to the first positive terminal portion. In the first direction, the distance between the first edge and the axis of the first through hole near the first edge is D1, the distance between the second edge and the axis of the first through hole near the second edge is D2, and the distance between the axes of the two first through holes is D3. D1 / D2 is 0.9-1.1, and (D1+D2) / D3 is 0.9-1.1.

[0033] Viewed from the thickness direction, the two third positive terminal parts are approximately symmetrically arranged, which can improve the stability of the first positive terminal part and increase the structural strength of the positive terminal.

[0034] In some embodiments, the cross-section of the third positive terminal portion perpendicular to the thickness direction of the first wall portion is circular, elliptical, or racetrack-shaped.

[0035] In some embodiments, the positive electrode tab is soldered to the second positive terminal portion and forms a first solder mark. Directly soldering the positive electrode tab to the second positive terminal portion can shorten the conductive path between the positive electrode tab and the second positive terminal portion, reduce resistance, and reduce heat generation of the positive electrode tab and the second positive terminal portion.

[0036] In some embodiments, the first solder mark is configured to at least partially overlap with the heat exchange element of the battery in the thickness direction of the first wall portion. The first solder mark generates heat when current passes through it. Embodiments of this application can reduce the distance between the first solder mark and the heat exchange element, thereby improving the heat dissipation efficiency of the first solder mark and reducing its temperature rise.

[0037] In some embodiments, in the thickness direction of the first wall portion, the projected area of ​​the first positive terminal is larger than the projected area of ​​the second positive terminal. Compared to the second positive terminal, the first positive terminal can have a larger area, which can improve the heat dissipation efficiency of the first positive terminal; provided that the overcurrent area meets the requirements, the second positive terminal can have a smaller area than the first positive terminal, thereby saving internal space of the casing and increasing the energy density of the battery cell.

[0038] In some embodiments, in the thickness direction of the first wall portion, the projected area of ​​the second positive terminal is 0.2-0.5 times the projected area of ​​the first wall portion. When the ratio of the projected area of ​​the second positive terminal to the projected area of ​​the first wall portion is greater than or equal to 0.2, the second positive terminal and the positive electrode tab can have a larger connection area and current-carrying area, thereby reducing resistance, heat generation in the second positive terminal and the positive electrode tab, and lowering the temperature rise of the battery cell. When the ratio of the projected area of ​​the second positive terminal to the projected area of ​​the first wall portion is less than or equal to 0.5, installation space can be reserved for other components inside the casing, reducing the risk of interference or short circuit between the second positive terminal and other components, and improving the reliability of the battery cell.

[0039] In some embodiments, in the thickness direction of the first wall portion, the projected area of ​​the first positive terminal is 0.2-0.5 times the projected area of ​​the first wall portion. When the ratio of the projected area of ​​the first positive terminal to the projected area of ​​the first wall portion is greater than or equal to 0.2, the first positive terminal can have a larger exposed area for heat dissipation, thereby reducing the temperature rise of the first positive terminal and the positive electrode tab, and improving the cycle performance and reliability of the battery cell. When the ratio of the projected area of ​​the first positive terminal to the projected area of ​​the first wall portion is less than or equal to 0.5, installation space can be reserved for other components of the battery cell.

[0040] In some embodiments, the first negative terminal is used to connect to the second busbar of the battery and exchange heat with the battery's heat exchange component. During battery cycling, both the first positive terminal and the first negative terminal can exchange heat with the heat exchange component, thereby further improving the heat dissipation capacity of the battery cell, reducing the temperature rise of the battery cell, improving the cycle performance and cycle life of the battery cell, and reducing the risk of thermal runaway of the battery cell during fast charging. The negative terminal is connected to the negative electrode tab, and the heat from the negative electrode tab can also be conducted to the heat exchange component through the first negative terminal, thereby reducing the temperature rise of the electrode assembly and improving the cycle performance and cycle life of the battery cell. The first negative terminal can simultaneously serve the functions of heat dissipation and current transmission, which helps to shorten the heat transfer path between the heat source and the heat exchange component and improve heat dissipation efficiency.

[0041] In some embodiments, the negative terminal is disposed on the first wall portion. The surface of the first positive terminal portion away from the first wall portion includes a first region and a second region, the first region being configured to overlap and connect with the first busbar of the battery in the thickness direction of the first wall portion. The surface of the first negative terminal portion away from the first wall portion includes a third region and a fourth region, the third region being configured to overlap and connect with the second busbar in the thickness direction of the first wall portion. The second and fourth regions are configured to overlap with the heat exchanger in the thickness direction of the first wall portion.

[0042] In some embodiments, the first region, the second region, the fourth region, and the third region are arranged sequentially at intervals along a first direction. The first direction is perpendicular to the thickness direction of the first wall. The second region and the fourth region are arranged adjacent to each other along the first direction, and the same heat exchanger can exchange heat with both the second region and the fourth region simultaneously, thereby simplifying the battery structure.

[0043] In some embodiments, the second region, the first region, the third region, and the fourth region are arranged sequentially at intervals along the first direction. When multiple battery cells are arranged along the first direction, the second region of one battery cell is adjacent to the fourth region (or second region) of another battery cell, and the same heat exchanger can exchange heat with two battery cells simultaneously, thereby simplifying the battery structure.

[0044] In some embodiments, the housing is provided with a positive lead-out hole and a negative lead-out hole. The positive terminal also includes a second positive terminal portion and a third positive terminal portion. The second positive terminal portion is located inside the first wall portion and electrically connected to the positive electrode tab. At least a portion of the third positive terminal portion is accommodated in the positive lead-out hole, and the third positive terminal portion connects the second positive terminal portion and the first positive terminal portion. The negative terminal also includes a second negative terminal portion and a third negative terminal portion. The second negative terminal portion is located inside the housing and electrically connected to the negative electrode tab. At least a portion of the third negative terminal portion is accommodated in the negative lead-out hole, and the third negative terminal portion connects the second negative terminal portion and the first negative terminal portion.

[0045] In some embodiments, the projected area of ​​the second positive terminal portion along its own thickness direction is larger than the projected area of ​​the second negative terminal portion along its own thickness direction. Compared to the second negative terminal portion, the second positive terminal portion can have a larger flow area, thereby reducing heat generation in the second positive terminal portion and the positive electrode tab, reducing the temperature difference between the positive and negative electrode tabs, and improving the cycle performance of the battery cell.

[0046] In some embodiments, the projected area of ​​the first positive terminal part along its own thickness direction is 1.2-5 times the projected area of ​​the first negative terminal part along its own thickness direction. Optionally, the projected area of ​​the first positive terminal part along its own thickness direction is 2-3 times the projected area of ​​the first negative terminal part along its own thickness direction.

[0047] The embodiments of this application can make the first positive terminal portion have a larger exposed area and limit the difference between the heat dissipation area of ​​the first positive terminal portion and the heat dissipation area of ​​the first negative terminal portion, so as to improve the efficiency of heat dissipation of the first positive terminal portion and reduce the temperature difference between the positive electrode tab and the negative electrode tab.

[0048] In some embodiments, both the positive and negative terminals are disposed on the first wall portion. In the thickness direction of the first wall portion, the projected area of ​​the first positive terminal is S1, the projected area of ​​the first negative terminal is S2, and the projected area of ​​the first wall portion is S3. S1, S2, and S3 satisfy: 0.2 ≤ (S1 + S2) / S3 ≤ 0.8; optionally, 0.3 ≤ (S1 + S2) / S3 ≤ 0.5.

[0049] Setting (S1+S2) / S3 to be greater than or equal to 0.2 allows the first positive terminal and the first negative terminal to have larger areas, thereby improving the heat dissipation and current carrying capacity of both the positive and negative terminals, and improving the cycle performance of the battery cell. Setting (S1+S2) / S3 to be less than or equal to 0.8 allows for the provision of installation space for other components and maintains the distance between the first and second positive terminals, reducing the risk of short circuits.

[0050] In some embodiments, the housing includes a second wall portion, and a negative terminal is disposed on the second wall portion. In the thickness direction of the first wall portion, the projected area of ​​the first positive terminal is S1, and the projected area of ​​the first wall portion is S3. S1 and S3 satisfy: 0.2 ≤ S1 / S3 ≤ 0.8; optionally, 0.3 ≤ S1 / S3 ≤ 0.5.

[0051] Setting S1 / S3 to a value greater than or equal to 0.3 allows the first positive terminal to have a larger area, thereby improving its heat dissipation and current carrying capacity, and enhancing the cycle performance of the battery cell. Setting S1 / S3 to a value less than or equal to 0.8 allows for the provision of installation space for other components, reducing the impact of increasing the size of the first positive terminal on the energy density of the battery cell.

[0052] In some embodiments, the positive electrode tab is made of aluminum, and the negative electrode tab is made of copper. The positive terminal is made of aluminum or an aluminum alloy, and at least a portion of the negative terminal is made of copper or a copper alloy.

[0053] Compared to copper, aluminum has higher electrical and thermal resistance, making the positive electrode tab more prone to temperature rise than the negative electrode tab. This application's embodiments employ differentiated designs for the first positive and first negative electrode portions to increase the heat dissipation area and capacity of the first positive electrode portion, thereby reducing the temperature difference between the positive and negative electrode tabs and improving the cycle performance and cycle life of the battery cell.

[0054] In some embodiments, the negative terminal is disposed on the first wall portion. In the thickness direction of the first wall portion, the first positive terminal portion overlaps with the heat exchange component of the battery, while the first negative terminal portion does not overlap with the heat exchange component.

[0055] Compared to the first negative terminal, the first positive terminal is closer to the heat exchanger. This further improves the efficiency of heat dissipation from the first positive terminal, reduces heat accumulation on the positive electrode tab, lowers the temperature difference between the positive and negative electrode tabs, and improves the cycle performance and cycle life of the battery cell. Furthermore, if the heat exchange efficiency between the heat exchanger and the first positive terminal meets the requirements, the heat exchanger may not need to exchange heat with the first negative terminal. This reduces the size of the heat exchanger, simplifies its installation, and increases the battery's energy density.

[0056] In some embodiments, the housing includes a second wall, and the battery cell includes a pressure relief mechanism disposed on the second wall. By disposing the pressure relief mechanism on the second wall, more space can be reserved on the first wall for installing the positive terminal, allowing the first positive terminal to have a larger exposed area, improving the heat dissipation capacity of the first positive terminal, reducing the temperature rise of the first positive terminal and the positive electrode tab, and improving the cycle performance and cycle life of the battery cell.

[0057] In some embodiments, the first wall portion is provided with an electrolyte injection port. During the production process of the battery cell, electrolyte can be injected into the casing through the electrolyte injection port.

[0058] In some embodiments, the housing includes a shell and an end cap, the shell having an opening, and the end cap being connected to the shell and covering the opening. The end cap is a first wall portion. Compared to the shell, the end cap typically has a larger thickness; placing the positive terminal on the end cap can improve the connection strength between the positive terminal and the end cap, enhance the stability of the positive terminal, and reduce the risk of positive terminal misalignment.

[0059] Secondly, embodiments of this application provide a battery, including a battery cell, a first busbar, and a heat exchanger as provided in any of the embodiments of the first aspect. The first busbar is connected to a first positive terminal. At least a portion of the heat exchanger is located on the side of the first wall facing away from the electrode assembly and exchanges heat with the first positive terminal.

[0060] In some embodiments, a portion of the first positive terminal portion is located between the heat exchanger and the first wall portion in the thickness direction of the first wall portion. The heat exchanger is capable of exchanging heat with the first positive terminal portion, thereby improving the heat dissipation efficiency of the battery cell and improving the cycle performance of the battery cell.

[0061] In some embodiments, the battery further includes a housing. The battery cells and the first busbar are housed within the housing. A heat exchanger is disposed outside the housing, saving internal space and improving space utilization.

[0062] Thirdly, embodiments of this application provide an electrical device that includes a battery provided in any of the embodiments of the second aspect, the battery being used to provide electrical energy. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0064] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0065] Figure 2 is a schematic diagram of a battery provided in some embodiments of this application;

[0066] Figure 3 is a schematic diagram of a partial structure of a battery provided in some embodiments of this application;

[0067] Figure 4 is a partial cross-sectional schematic diagram of a battery provided in some embodiments of this application;

[0068] Figure 5 is a schematic diagram of the battery structure provided in some embodiments of this application;

[0069] Figure 6 is a schematic diagram of the explosion of the battery cell shown in Figure 5;

[0070] Figure 7 is an enlarged view of Figure 4 at box A;

[0071] Figure 8 is an enlarged view of the area in box B of Figure 4;

[0072] Figure 9 is a schematic diagram of the end cap assembly of a battery cell provided in some embodiments of this application;

[0073] Figure 10 is a top view of the end cap assembly shown in Figure 9;

[0074] Figure 11 is a bottom view of the end cap assembly shown in Figure 9;

[0075] Figure 12 is a structural schematic diagram of the end cap assembly provided in some other embodiments of this application;

[0076] Figure 13 is a top view of the end cap assembly shown in Figure 12;

[0077] Figure 14 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0078] Figure 15 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0079] Figure 16 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0080] Figure 17 is a cross-sectional schematic diagram of the end cap assembly shown in Figure 16;

[0081] Figure 18 is a top view of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0082] Figure 19 is a schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0083] Figure 20 is a schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application;

[0084] Figure 21 is a simplified schematic diagram of a battery cell provided in some other embodiments of this application;

[0085] Figure 22 is a cross-sectional schematic diagram of a battery provided in some embodiments of this application.

[0086] The accompanying drawings are not drawn to scale.

[0087] Explanation of reference numerals in the attached figures:

[0088] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 5a. First housing section; 5b. Second housing section; 6. Battery cell; 7. Busbar assembly; 7a. First busbar assembly; 7b. Second busbar assembly; 8. Heat exchange plate; 9. Heat exchange component; 9a. Thermal conductive adhesive;

[0089] 10. Electrode assembly; 11. Electrode body; 12. Positive electrode tab; 13. Negative electrode tab;

[0090] 20. Outer shell; 20a. First wall portion; 20b. Second wall portion; 21. Shell; 22. End cap; 221. Positive electrode lead-out port; 222. Negative electrode lead-out port; 223. Electrolyte injection port;

[0091] 30. Positive terminal; 31. First positive terminal portion; 311. First part; 312. Second part; 313. First recess; 314. First through hole; 31a. First region; 31b. Second region; 31c. First edge; 31d. Second edge; 32. Second positive terminal portion; 33. Third positive terminal portion;

[0092] 40. Negative end piece; 41. First negative end piece; 411. Third part; 412. Fourth part; 413. Second recess; 414. Second through hole; 41a. Third region; 41b. Fourth region; 41c. Third edge; 41d. Fourth edge; 41e. First plate; 41f. Second plate; 42. Second negative end piece; 43. Third negative end piece;

[0093] 50. End cap assembly;

[0094] 60. Pressure relief mechanism;

[0095] 70. Sealing sheet; 80a. First weld mark; 80b. Second weld mark;

[0096] X, first direction; Y, second direction; Z, thickness direction. Detailed Implementation

[0097] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0098] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0099] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0100] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0101] In this application, the term "and / or" 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. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0102] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0103] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, it is also expected that ranges of 60 to 110 and 80 to 120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise stated, the numerical range "a to b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 and 5" have been listed in this article; "0 to 5" is just a shortened representation of these numerical combinations. In addition, when a parameter is stated as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0104] In this application, "multiple" means two or more (including two).

[0105] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0106] A battery typically refers to a single physical module comprising multiple individual cells to provide higher voltage and capacity. A single cell can be the smallest unit that makes up a battery.

[0107] A battery cell includes an electrode assembly, which is the component within the cell where electrochemical reactions occur. The electrode assembly includes a positive electrode tab and a negative electrode tab, which transfer current during the cell's cycling process. When current flows through the positive and negative electrode tabs, they generate heat. Due to differences in materials, current-carrying area, or other factors, the temperature of the positive electrode tab may be higher than that of the negative electrode tab. This affects the temperature uniformity of the electrode assembly, causing localized overheating and impacting the cell's cycle performance and cycle life.

[0108] In view of this, this application provides a technical solution that differentiates the exposed area of ​​the positive terminal connected to the positive electrode tab and the exposed area of ​​the negative terminal connected to the negative electrode tab, thereby reducing the temperature difference between the positive and negative electrode tabs and improving the cycle performance and cycle life of the battery cell.

[0109] The batteries described in this application are applicable to electrical devices that use batteries. Electrical devices can be equipment that uses batteries as a power source or various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0110] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0111] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0112] As shown in Figure 1, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0113] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0114] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0115] Figure 2 is a schematic diagram of a battery provided in some embodiments of this application.

[0116] Referring to FIG2, in some embodiments, the battery 2 includes a housing 5 and a plurality of battery cells 6 housed within the housing 5.

[0117] The battery cell 6 can be a secondary battery cell, which refers to the battery cell 6 that can be recharged to activate the active materials and continue to be used after the battery cell 6 has been discharged.

[0118] For example, the battery cell 6 can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0119] As an example, the battery cell 6 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include square battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0120] Multiple battery cells 6 can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 6 are connected in both series and parallel. Multiple battery cells 6 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 6 is housed in the housing 5. Alternatively, multiple battery cells 6 can first be connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole assembly, which is then housed in the housing 5.

[0121] In some embodiments, the housing 5 is used to house the battery cell 6, and the housing 5 can have various structures.

[0122] In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a receiving space for accommodating the battery cell 6. The second housing portion 5b may be a hollow structure with one open end, and the first housing portion 5a may be a plate-like structure, covering the open side of the second housing portion 5b to form a housing 5 with a receiving space; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one open side, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with a receiving space. Of course, the first housing portion 5a and the second housing portion 5b may be of various shapes, such as cylinders, cuboids, etc.

[0123] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0124] In some embodiments, the housing 5 may be part of the vehicle's chassis structure. For example, a portion of the housing 5 may be at least a portion of the vehicle's floor, or a portion of the housing 5 may be at least a portion of the vehicle's crossbeams and longitudinal beams.

[0125] In some embodiments, battery 2 can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0126] Figure 3 is a schematic diagram of a partial structure of a battery provided in some embodiments of this application.

[0127] Referring to FIG3, in some embodiments, the battery 2 includes a plurality of battery cells 6 and a plurality of busbars 7, the plurality of busbars 7 electrically connecting the plurality of battery cells 6.

[0128] Multiple busbar components 7 connect multiple battery cells 6 in series, parallel, or mixed connections.

[0129] Multiple busbar components 7 can adopt the same structure or different structures.

[0130] The busbar component 7 can be a single-layer structure or a multi-layer structure.

[0131] In some embodiments, a battery cell 6 includes a positive terminal 30 and a negative terminal 40. As an example, a busbar 7 is connected to the positive terminal 30 of one battery cell 6 and the negative terminal 40 of another battery cell 6 to connect the two battery cells 6 in series. Alternatively, the busbar 7 is connected to the positive terminals 30 of both battery cells 6 to connect the two battery cells 6 in parallel.

[0132] In some embodiments, the busbar 7 is welded to the positive terminal 30 or the negative terminal 40.

[0133] In some embodiments, the busbar component 7 has a multi-layer structure. Exemplarily, the busbar component 7 has a multi-layer structure in its thickness direction, for example, the busbar component 7 is formed into a two-layer structure or a three-layer structure by bending.

[0134] Each layer of the busbar component 7 can transmit current. By setting the busbar component 7 as a multi-layer structure, the current-carrying area of ​​the busbar component 7 can be increased, the heat generated when the busbar component 7 is overcurrent can be reduced, the temperature rise of the battery cell 6 can be reduced, and the fast charging capability of the battery cell 6 can be improved.

[0135] Provided the flow area meets the requirements, configuring the busbar component 7 as a multi-layer structure can reduce the thickness of each layer. During cycling, the battery cell 6 expands, stretching the layer of the busbar component 7 connected to the battery cell 6. A single layer of the busbar component 7 with a small thickness is easily deformable to accommodate the expansion and deformation of the battery cell 6, thereby reducing the risk of tearing at the connection between the battery cell 6 and the busbar component 7 and improving the reliability of the battery 2.

[0136] In some embodiments, the battery 2 further includes a heat exchange plate 8 for exchanging heat with the casing of the battery cell 6.

[0137] The heat exchange plate 8 can exchange heat with the battery cell 6 during the cycle, thereby keeping the battery cell 6 within a suitable temperature range, improving the cycle performance and cycle life of the battery cell 6, and reducing the risk of thermal runaway.

[0138] In some embodiments, the housing has two large surfaces disposed opposite each other in the thickness direction of the battery cell 6. Along the thickness direction of the battery cell 6, a heat exchange plate 8 is disposed on at least one side of the battery cell 6 and exchanges heat with the large surface of the battery cell 6.

[0139] The large surface is the largest surface on the outer surface of the casing. By exchanging heat with the heat exchange plate 8, the heat exchange efficiency is improved, thereby reducing the temperature rise of the battery cell 6 during fast charging, improving the cycle performance and cycle life of the battery cell 6, reducing the risk of thermal runaway, and improving reliability.

[0140] In some embodiments, heat exchange plates 8 are provided on both sides of the battery cell 6, that is, the two large surfaces of the battery cell 6 exchange heat with the two heat exchange plates 8 respectively.

[0141] In some embodiments, the battery 2 includes a plurality of heat exchange plates 8, which are arranged along the thickness direction of the battery cell 6. Battery cells 6 are disposed between adjacent heat exchange plates 8.

[0142] In some embodiments, the battery 2 further includes a heat exchanger 9.

[0143] In some examples, heat exchanger 9 is used to exchange heat with the positive terminal 30. In other examples, heat exchanger 9 is used to exchange heat with the negative terminal 40. In some examples, heat exchanger 9 exchanges heat with both the positive terminal 30 and the negative terminal 40 simultaneously.

[0144] As an example, the positive terminal 30 and the negative terminal 40 of the same battery cell 6 can both exchange heat with the heat exchanger 9, or only the positive terminal 30 or only the negative terminal 40 can exchange heat with the heat exchanger 9.

[0145] As an example, for two adjacent battery cells 6, the heat exchanger 9 can exchange heat with the positive terminals 30 of both battery cells 6 at the same time, or with the negative terminals 40 of both battery cells 6 at the same time, or with the positive terminal 30 of one battery cell 6 and the negative terminal 40 of the other battery cell 6, or with the positive terminals 30 and the negative terminals 40 of both battery cells 6 at the same time.

[0146] As an example, the heat exchanger 9 can directly contact the electrode terminals (e.g., the positive terminal or / or the negative terminal) for heat exchange, or it can indirectly exchange heat with the electrode terminals through other heat-conducting components.

[0147] As an example, the heat exchanger 9 can be located inside or outside the housing 5. Optionally, the heat exchanger 9 can be located outside the housing 5 and exchange heat with the electrode terminals through the housing 5.

[0148] In some embodiments, the heat exchanger 9 includes a heat exchange tube. Exemplarily, the heat exchange tube is a flat tube.

[0149] In some embodiments, the heat exchanger 9 has a flow channel inside; when the heat exchange medium flows through the flow channel, it exchanges heat with the electrode terminals through the heat exchanger 9.

[0150] Figure 4 is a partial cross-sectional view of a battery provided in some embodiments of this application; Figure 5 is a structural schematic diagram of a battery provided in some embodiments of this application; Figure 6 is an exploded view of the battery cell shown in Figure 5; Figure 7 is an enlarged view of Figure 4 at box A; Figure 8 is an enlarged view of Figure 4 at box B; Figure 9 is a structural schematic diagram of the end cap assembly of the battery cell provided in some embodiments of this application; Figure 10 is a top view of the end cap assembly shown in Figure 9; Figure 11 is a bottom view of the end cap assembly shown in Figure 9.

[0151] Referring to Figures 4 to 11, in some embodiments, the battery cell 6 includes a housing 20 and an electrode assembly 10, at least a portion of which is housed within the housing 20.

[0152] The outer shell 20 is a hollow structure, forming an internal space for accommodating the electrode assembly 10 and the electrolyte. The shape of the outer shell 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cuboid structure, a cuboid outer shell can be used.

[0153] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening, and the end cap 22 being connected to the housing 21 and covering the opening;

[0154] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the battery cell 6. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0155] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 6.

[0156] The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not impose any special limitations on this.

[0157] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the battery cell 6 can have higher structural strength and improve reliability.

[0158] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0159] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0160] Electrode assembly 10 is a component in the battery cell 6 where electrochemical reactions occur. The housing 21 may contain one or more electrode assemblies 10.

[0161] In some embodiments, the electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 6, active ions (e.g., lithium ions) are inserted and extracted back and forth between the positive and negative electrode.

[0162] In some embodiments, the electrode assembly 10 further includes a separator membrane disposed between the positive electrode and the negative electrode, which can prevent short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0163] In some embodiments, the positive electrode sheet may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector. Exemplarily, the portion of the positive current collector without the positive electrode film layer may serve as a positive electrode tab.

[0164] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0165] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector. Exemplarily, the portion of the negative electrode current collector without the negative electrode film layer may serve as a negative electrode tab.

[0166] In some embodiments, the electrode assembly 10 includes an electrode body 11, a positive electrode tab 12, and a negative electrode tab 13, which extend from the electrode body 11.

[0167] As an example, the positive electrode sheet has a portion coated with a positive electrode film layer for the positive current collector, a portion coated with a negative electrode film layer for the negative current collector, a positive electrode film layer, a negative electrode film layer, and a separator film constituting an electrode body 11. The positive electrode tab 12 and the negative electrode tab 13 can be led out from the same end of the electrode body 11, or they can be led out from the two ends of the electrode body 11 respectively.

[0168] In some embodiments, the electrode assembly 10 is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0169] In some embodiments, the electrode assembly 10 has a stacked structure.

[0170] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0171] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0172] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0173] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0174] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0175] In some embodiments, the battery cell 6 includes a positive terminal 30 and a negative terminal 40 that are insulated from each other, with the positive terminal 30 electrically connected to the positive electrode tab 12 and the negative terminal 40 electrically connected to the negative electrode tab 13.

[0176] The positive terminal 30 and the negative terminal 40 are used for electrical connection with an external circuit to enable charging or discharging of the battery cell 6.

[0177] As an example, the positive terminal 30 may be a separately molded component that is mounted on the housing 20. Alternatively, the positive terminal 30 may also be part of the housing 20.

[0178] As an example, the negative terminal 40 may be a separately molded component that is mounted on the housing 20. Alternatively, the negative terminal 40 may also be part of the housing 20.

[0179] In some embodiments, both the positive terminal 30 and the negative terminal 40 are disposed on the end cap 22. As an example, the end cap 22, the positive terminal 30, and the negative terminal 40 can be pre-assembled together and then assembled with the electrode assembly 10 and the housing 21.

[0180] For example, the battery cell 6 includes an end cap assembly 50, which includes an end cap 22, a positive terminal 30, and a negative terminal 40. Optionally, both the positive terminal 30 and the negative terminal 40 are insulated from the end cap 22. Optionally, the positive terminal 30 is riveted to the end cap 22, and the negative terminal 40 is riveted to the end cap 22.

[0181] In some embodiments, the battery cell 6 further includes a pressure relief mechanism 60. The pressure relief mechanism 60 has a significant impact on the reliability of the battery cell 6. For example, when a short circuit or overcharging occurs, thermal runaway may occur inside the battery cell 6, causing a sudden increase in pressure. In this case, the pressure relief mechanism 60 can be activated to release the internal pressure to the outside, thereby reducing the risk of the battery cell 6 exploding or catching fire.

[0182] For example, the pressure relief mechanism 60 refers to a component or part that is actuated to release internal gas when the internal pressure or temperature of the battery cell 6 reaches a predetermined threshold. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 6.

[0183] The pressure relief mechanism 60 can take the form of an explosion-proof valve, a gas valve, a pressure relief valve, or a safety valve, and can specifically employ a pressure-sensitive element or structure. That is, when the internal pressure of the battery cell 6 reaches a predetermined threshold, the pressure relief mechanism 60 actuates or a weak area provided in the pressure relief mechanism 60 ruptures, thereby forming an opening or channel for internal pressure release. Alternatively, the pressure relief mechanism 60 can also employ a temperature-sensitive element or structure, that is, when the internal temperature of the battery cell 6 reaches a predetermined threshold, the pressure relief mechanism 60 actuates, thereby forming an opening or channel for internal pressure release.

[0184] When battery cell 6 experiences thermal runaway, the emissions from battery cell 6 include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0185] In some embodiments, the pressure relief mechanism 60 is disposed on the housing 20. Exemplarily, the pressure relief mechanism 60 may be disposed on the housing 21 or on the end cap 22.

[0186] In some embodiments, this application provides a battery cell 6, which includes an electrode assembly 10, a housing 20, a positive terminal 30, and a negative terminal 40. The housing 20 includes a first wall portion 20a. The electrode assembly 10 is housed within the housing 20 and includes a positive electrode tab 12 and a negative electrode tab 13. The positive terminal 30 is disposed on the first wall portion 20a and electrically connected to the positive electrode tab 12. The positive terminal 30 includes a first positive terminal portion 31 located outside the first wall portion 20a. The negative terminal 40 is disposed on the housing 20 and electrically connected to the negative electrode tab 13. The negative terminal 40 includes a first negative terminal portion 41 located outside the housing 20. The projected area of ​​the first positive terminal portion 31 along its own thickness direction is larger than the projected area of ​​the first negative terminal portion 41 along its own thickness direction.

[0187] The first wall portion 20a can be an end cap 22 or a wall of the housing 21. The negative terminal 40 can be disposed on the first wall portion 20a or on other walls of the housing 20 (second wall portion 20b).

[0188] The positive terminal 30 can be directly connected to the positive electrode tab 12, or indirectly connected through other conductive structures. The negative terminal 40 can be directly connected to the positive electrode tab 13, or indirectly connected through other conductive structures.

[0189] There can be one or more positive extremes (30). There can be one or more negative extremes (40).

[0190] As an example, in the thickness direction Z of the first wall portion 20a, the first positive terminal portion 31 is located on the side of the end cap 22 away from the electrode body 11.

[0191] As an example, the thickness direction of the first positive terminal portion 31 may be parallel to the thickness direction Z of the first wall portion 20a.

[0192] The thickness direction of the first negative terminal portion 41 is related to the position of the negative terminal 40. For example, the first negative terminal portion 41 is disposed on the first wall portion 20a, and the thickness direction of the first negative terminal portion 41 may be parallel to the thickness direction Z of the first wall portion 20a. For example, the first negative terminal portion 41 is disposed on the second wall portion 20b, and the thickness direction of the first negative terminal portion 41 may be parallel to the thickness direction of the second wall portion 20b.

[0193] The material of the first negative terminal 41 can be the same as or different from the material of the first positive terminal 31.

[0194] During the cycling process of the battery cell 6, the positive electrode tab 12 and the negative electrode tab 13 generate heat when current flows through them. Part of the heat from the positive electrode tab 12 can be dissipated outwards via the first positive terminal portion 31, and part of the heat from the negative electrode tab 13 can be dissipated outwards via the first negative terminal portion 41, thereby reducing the temperature rise of both the positive and negative electrode tabs. In this embodiment, the projected area of ​​the first positive terminal portion 31 along its thickness direction is larger than the projected area of ​​the first negative terminal portion 41 along its thickness direction. This allows the first positive terminal portion 31 to have a larger exposed area, thereby improving the efficiency of heat dissipation from the first positive terminal portion 31, reducing the heat accumulated on the positive electrode tab 12, reducing the temperature difference between the positive and negative electrode tabs 12, and improving the cycle performance and cycle life of the battery cell 6.

[0195] In some embodiments, the first positive terminal 31 is used to connect to the first busbar component 7a of the battery and exchange heat with the heat exchanger 9 of the battery.

[0196] The first positive terminal 31 can exchange heat with the heat exchanger 9, thereby further reducing the temperature rise of the positive electrode tab 12, reducing the temperature difference between the positive electrode tab 12 and the negative electrode tab 13, improving the heat dissipation capacity of the battery cell 6, improving the cycle performance and cycle life of the battery cell 6, and reducing the risk of thermal runaway of the battery cell 6 during fast charging.

[0197] During the cycling process of battery 2, current flows through the first busbar 7a and the first positive terminal 31, causing heat to be generated in the first positive terminal 31 and the first busbar 7a. Exchanging heat between the first positive terminal 31 and the heat exchanger 9 helps to shorten the heat transfer path between the heat source and the heat exchanger 9, thereby improving heat dissipation efficiency.

[0198] In some embodiments, in the thickness direction Z of the first wall portion 20a, the distance between the heat exchanger 9 and the positive terminal 30 is less than the distance between the heat exchange plate 8 and the positive terminal 30.

[0199] In some embodiments, the heat exchange plate 8 does not overlap with the positive terminal 30 in the thickness direction Z of the first wall portion 20a.

[0200] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening, and the end cap 22 being connected to the housing 21 and covering the opening. The end cap 22 is a first wall portion 20a.

[0201] Compared to the housing 21, the end cap 22 usually has a larger thickness; placing the positive terminal 30 on the end cap 22 can improve the connection strength between the positive terminal 30 and the end cap 22, enhance the stability of the positive terminal 30, and reduce the risk of the positive terminal 30 shifting.

[0202] During the production of battery cell 6, the positive terminal 30 and end cap 22 can be pre-assembled and then assembled with components such as housing 21 and electrode assembly 10. The positive terminal 30 and end cap 22 are supplied as a single piece, which simplifies the assembly process.

[0203] In some embodiments, the first wall portion 20a is provided with an electrolyte injection hole 223. During the production process of the battery cell 6, electrolyte can be injected into the casing 20 through the electrolyte injection hole 223.

[0204] After the process related to the electrolyte injection port 223 is completed, a sealing plate 70 can be installed on the first wall portion 20a to seal the electrolyte injection port 223.

[0205] In some embodiments, the positive terminal 30 is directly connected to the positive electrode tab 12. Alternatively, the positive terminal 30 is soldered to the positive electrode tab 12.

[0206] Connecting the positive terminal 30 directly to the positive electrode tab 12 saves on traditional adapter pieces, shortens the conductive path, reduces resistance, and decreases heat generation. Furthermore, directly connecting the positive terminal 30 to the positive electrode tab 12 also shortens the heat transfer path between the positive electrode tab 12 and the heat exchanger 9, improving heat dissipation and reducing the temperature rise of the positive electrode tab 12.

[0207] In some embodiments, the negative terminal 40 is directly connected to the negative electrode tab 13. Optionally, the negative terminal 40 is soldered to the negative electrode tab 13. Directly connecting the negative terminal 40 to the negative electrode tab 13 can save on traditional adapter pieces, shorten the conductive and heat transfer paths between the negative electrode tab 13 and the first negative terminal portion 41, reduce resistance, reduce heat generation, and lower the temperature rise of the negative electrode tab 13.

[0208] In some embodiments, the negative terminal 40 may or may not exchange heat with the heat exchanger 9.

[0209] In some embodiments, the negative terminal 40 can be used to connect the second busbar component 7b of the battery.

[0210] The positive terminal 30 and negative terminal 40 of the battery cell 6 are generally connected to two current collectors 7 respectively. The current collector 7 connected to the positive terminal 30 is the first current collector 7a, and the current collector 7 connected to the negative terminal 40 is the second current collector 7b.

[0211] As an example, two adjacent battery cells 6 are connected in series by a busbar 7, which is connected to the positive terminal 30 of one battery cell 6 and the negative terminal 40 of the other battery cell 6; correspondingly, the busbar 7 is the first busbar 7a for one battery cell 6 and the second busbar 7b for the other battery cell 6.

[0212] In some embodiments, the housing 20 includes a second wall portion 20b, and the battery cell 6 includes a pressure relief mechanism 60 disposed on the second wall portion 20b.

[0213] The second wall portion 20b can be a wall portion disposed opposite to the first wall portion 20a, or it can be a wall portion directly connected to the first wall portion 20a.

[0214] By placing the pressure relief mechanism 60 on the second wall portion 20b, more space can be reserved on the first wall portion 20a to install the positive terminal 30, allowing the first positive terminal portion 31 to have a larger exposed area, improving the heat dissipation capacity of the first positive terminal portion 31, reducing the temperature rise of the first positive terminal portion 31 and the temperature rise of the positive electrode tab 12, and improving the cycle performance and cycle life of the battery cell 6.

[0215] In some embodiments, along the thickness direction Z of the first wall portion 20a, the first wall portion 20a and the second wall portion 20b are located on both sides of the electrode body 11.

[0216] As an example, the second wall portion 20b is the bottom wall of the housing 21.

[0217] In some embodiments, the positive electrode tab 12 is made of aluminum, and the negative electrode tab 13 is made of copper. The positive terminal 30 is made of aluminum or an aluminum alloy, and at least a portion of the negative terminal 40 is made of copper or a copper alloy.

[0218] Compared to copper, aluminum has higher electrical and thermal resistance, making the positive electrode tab 12 more prone to temperature rise than the negative electrode tab 13. This application embodiment employs a differentiated design for the first positive terminal portion 31 and the first negative terminal portion 41 to increase the heat dissipation area and capacity of the first positive terminal portion 31, thereby reducing the temperature difference between the positive electrode tab 12 and the negative electrode tab 13 and improving the cycle performance and cycle life of the battery cell 6.

[0219] In addition, by exchanging heat between the heat exchanger 9 and the first positive terminal 31, the efficiency of heat dissipation from the positive electrode tab 12 can be further improved, and the temperature difference between the positive electrode tab 12 and the negative electrode tab 13 can be reduced.

[0220] In some embodiments, the projection of the first positive end portion 31 along the thickness direction Z is generally rectangular.

[0221] In some embodiments, the first positive terminal sub-part 31 includes a first portion 311 and a second portion 312, the first portion 311 being used to connect to the first busbar 7a, and the second portion 312 being used to exchange heat with the heat exchanger 9.

[0222] The thickness of the first part 311 and the thickness of the second part 312 can be the same or different.

[0223] In the first direction X, the dimensions of the first part 311 and the second part 312 may be the same or different; in the second direction Y, the dimensions of the first part 311 and the second part 312 may be the same or different.

[0224] As an example, the first direction X, the second direction Y, and the thickness direction Z of the first wall portion 20a are perpendicular to each other.

[0225] As an example, the first direction X is parallel to the length direction of the first wall portion 20a, and the second direction Y is parallel to the width direction of the first wall portion 20a.

[0226] The first part 311 and the second part 312 can be connected or separated. Optionally, the first part 311 and the second part 312 can be directly connected.

[0227] In this embodiment, the first busbar component 7a and the heat exchanger 9 act on different parts of the first positive terminal 31, which can reduce the risk of interference between the first busbar component 7a and the heat exchanger 9.

[0228] In some embodiments, the first portion 311 is configured to at least partially overlap and connect with the first busbar 7a in the thickness direction Z of the first wall portion 20a, and the second portion 312 is configured to at least partially overlap with the heat exchanger 9 in the thickness direction Z of the first wall portion 20a.

[0229] The first part 311 and the first busbar 7a are arranged along the thickness direction Z, which increases the connection strength and flow area between them and reduces heat generation. The second part 312 and the heat exchanger 9 are arranged along the thickness direction Z, which increases the heat exchange area between them and improves heat exchange efficiency. The first busbar 7a and the heat exchanger 9 can share space in the thickness direction Z, thereby improving space utilization in the thickness direction Z and increasing the energy density of the battery 2.

[0230] In some embodiments, the first busbar component 7a is disposed on the side of the first portion 311 away from the first wall portion 20a and connected to the first portion 311.

[0231] In some embodiments, the heat exchanger 9 is disposed on the side of the second portion 312 away from the first wall portion 20a.

[0232] In some embodiments, the thickness t1 of the first portion 311 is greater than the thickness t2 of the second portion 312.

[0233] For example, in the thickness direction Z of the first wall portion 20a, the surface of the first portion 311 away from the first wall portion 20a and the surface of the second portion 312 away from the first wall portion 20a may or may not be flush.

[0234] The first part 311 has a greater thickness than the second part 312. The first part 311 is less likely to be melted through when welded to the first busbar component 7a, thereby improving the reliability of the battery cell 6. The second part 312 does not need to be welded to the first busbar component 7a, and it can have a smaller thickness, thereby reducing the volume and weight of the positive terminal 30 and increasing the energy density of the battery cell 6.

[0235] In some embodiments, the thickness of the first portion 311 is greater than or equal to 3 mm.

[0236] In some embodiments, the thickness ratio of the first portion 311 to the second portion 312 is 1.2-3. Optionally, t1 / t2 is 1.2, 1.5, 2, 2.5 or 3.

[0237] In some embodiments, the first portion 311 extends beyond the second portion 312 in a direction away from the first wall portion 20a.

[0238] In the thickness direction Z of the first wall portion 20a, the surface of the second portion 312 away from the first wall portion 20a is closer to the first wall portion 20a than the surface of the second portion 312 away from the first wall portion 20a, thereby reserving more space on the side of the second portion 312 away from the first wall portion 20a to facilitate the arrangement of the heat exchanger 9 and improve space utilization.

[0239] In some embodiments, the first positive terminal portion 31 has a first recess 313 on the side away from the first wall portion 20a, and the second portion 312 is the bottom wall of the first recess 313.

[0240] By providing the first recess 313, the volume and weight of the first positive terminal portion 31 can be reduced, and the exposed area of ​​the first positive terminal portion 31 can be increased, thereby improving the heat dissipation capacity of the first positive terminal portion 31. By providing the first recess 313, space can also be provided for the heat exchanger 9, thereby improving the space utilization rate in the thickness direction Z of the first wall portion 20a.

[0241] In some embodiments, the first busbar 7a is laser welded to the first portion 311.

[0242] In some embodiments, the first recess 313 is located on one side of the first portion 311 along the first direction X. The end of the first recess 313 away from the first portion 311 along the first direction X may extend to the edge of the first positive terminal portion 31; alternatively, the end of the first recess 313 away from the first portion 311 along the first direction X may not extend to the edge of the first positive terminal portion 31, that is, the first positive terminal portion 31 may also include a third portion (not shown), the thickness of the third portion being greater than the thickness of the second portion 312, the second portion 312 connecting the first portion 311 and the third portion, and the first recess 313 located between the first portion 311 and the third portion in the first direction X.

[0243] In some embodiments, the first recess 313 extends through the first positive terminal portion 31 along the second direction Y.

[0244] In some embodiments, in the thickness direction Z of the first wall portion 20a, the depth h of the first recess 313 is 0.1 mm to 2 mm.

[0245] For example, h is 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, 1.6mm, 1.8mm or 2.0mm.

[0246] Limiting the depth of the first recess 313 to greater than or equal to 0.1 mm provides more space for other components (such as heat exchanger 9), improving space utilization. Limiting the depth of the first recess 313 to less than or equal to 2 mm can reduce the loss of thermal conductivity caused by the thinning of the second part 312, and to a certain extent, balance the heat exchange efficiency of the second part 312 and the heat exchanger 9.

[0247] In some embodiments, when viewed from the thickness direction Z, the area of ​​the second portion 312 is larger than the area of ​​the first portion 311, which allows for a larger heat exchange area between the first positive terminal portion 31 and the heat exchanger 9.

[0248] In some embodiments, the first portion 311 and the second portion 312 are disposed along a first direction X, which is perpendicular to the thickness direction Z of the first wall portion 20a. In the first direction X, the dimension L22 of the second portion 312 is larger than the dimension L21 of the first portion 311.

[0249] The second part 312 has a larger size than the first part 311 in the first direction X, which can increase the heat exchange area between the second part 312 and the heat exchanger 9, improve the heat exchange efficiency, reduce the temperature rise inside the battery cell 6, and improve the cycle performance of the battery cell 6.

[0250] The second part 312 has a smaller thickness, and increasing the size of the second part 312 L22 has a smaller impact on the weight of the battery cell compared to increasing the size of the first part 311 L21.

[0251] In some embodiments, the surface of the first positive terminal portion 31 away from the first wall portion 20a is configured to be connected to the heat exchanger 9.

[0252] As an example, the surface of the first positive terminal portion 31 away from the first wall portion 20a can be a plane or a stepped surface.

[0253] The surface of the first positive terminal 31 away from the first wall 20a can be in contact with the heat exchanger 9, or it can be indirectly connected to the heat exchanger 9 through other components. For example, the surface of the first positive terminal 31 away from the first wall 20a can be bonded to the heat exchanger 9 with thermally conductive adhesive.

[0254] In some embodiments, the surface of the first positive terminal portion 31 away from the first wall portion 20a includes a first region 31a and a second region 31b. The first region 31a is configured to overlap and connect with the first busbar 7a in the thickness direction Z of the first wall portion 20a, and the second region 31b is configured to overlap with the heat exchanger 9 in the thickness direction Z of the first wall portion 20a.

[0255] As an example, the first region 31a is fitted to the first busbar component 7a.

[0256] As an example, in the thickness direction Z, the projection of the second region 31b lies within the projection of the heat exchanger 9.

[0257] The first region 31a and the second region 31b can be flush, or they can be misaligned in the thickness direction Z of the first wall portion 20a.

[0258] As an example, in Figure 10, the first region 31a and the second region 31b are shown by diagonal lines.

[0259] The first region 31a and the second region 31b can be directly connected or set at intervals.

[0260] The first busbar component 7a and the heat exchanger 9 act on the first region 31a and the second region 31b respectively, which can reduce the risk of interference between the first busbar component 7a and the heat exchanger 9, and reduce the superposition of the first busbar component 7a and the heat exchanger 9 in the thickness direction Z, thereby improving space utilization.

[0261] In some embodiments, the first region 31a and the second region 31b are spaced apart to reduce the risk of interference between the first busbar component 7a and the heat exchanger 9 due to assembly errors.

[0262] In some embodiments, the area of ​​the second region 31b is larger than the area of ​​the first region 31a. The larger area of ​​the second region 31b can improve the heat exchange efficiency between the heat exchanger 9 and the first positive terminal 31, reduce the temperature rise of the first positive terminal 31, and improve the cycle performance and reliability of the battery cell 6.

[0263] In some embodiments, the ratio of the area of ​​the first region 31a to the projected area of ​​the first positive terminal 31 along the thickness direction Z of the first wall portion 20a is greater than or equal to 1.5%, thereby providing a larger connection area and higher connection strength between the first positive terminal 31 and the first busbar component 7a, improving the flow capacity between the first positive terminal 31 and the first busbar component 7a, reducing heat generation, and lowering the temperature rise.

[0264] As an example, the ratio of the area of ​​the first region 31a to the projected area of ​​the first positive end portion 31 along the thickness direction Z is 1.5%, 2%, 3%, 5%, 8%, 10%, 15%, 20%, 25%, or 30%.

[0265] In some embodiments, the area of ​​the first region 31a is greater than or equal to 20 mm². 2 Optionally, the area of ​​the first region 31a is 20 mm². 2 25mm 2 30mm 2 35mm 2 40mm 2 45mm 2 50mm 2 60mm 2 80mm 2 Or 100mm 2 The first positive terminal 31 and the first busbar component 7a have a large connection area and high connection strength, which improves the flow capacity between the first positive terminal 31 and the first busbar component 7a, reduces heat generation, and lowers the temperature rise.

[0266] In some embodiments, the ratio of the area of ​​the second region 31b to the projected area of ​​the first positive terminal portion 31 along the thickness direction Z of the first wall portion 20a is greater than or equal to 10%, thereby providing a larger heat exchange area between the first positive terminal portion 31 and the heat exchanger 9, improving the heat exchange efficiency between the first positive terminal portion 31 and the heat exchanger 9, reducing the temperature rise of the first positive terminal portion 31 and the temperature rise of the electrode assembly 10, and improving the cycle performance of the battery cell 6.

[0267] As an example, the ratio of the area of ​​the second region 31b to the projected area of ​​the first positive end portion 31 along the thickness direction Z is 10%, 12%, 14%, 15%, 18%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0268] In some embodiments, the ratio of the area of ​​the first region 31a to the projected area of ​​the first positive end portion 31 along the thickness direction Z is less than or equal to 70%, and optionally less than or equal to 40%.

[0269] In some embodiments, the first portion 311 includes a first region 31a, and the second portion 312 includes a second region 31b.

[0270] In some embodiments, the first wall portion 20a is provided with a positive lead-out hole 221.

[0271] As an example, the positive lead-out hole 221 penetrates the first wall portion 20a along the thickness direction Z of the first wall portion 20a.

[0272] There can be one or more positive lead-out holes 221.

[0273] The positive electrode lead-out hole 221 can be a round hole, a rectangular hole, an elliptical hole, a racetrack-shaped hole, or other shapes.

[0274] By providing a positive lead-out hole 221, an electrical connection can be made between the first positive terminal 31 and the positive terminal tab 12.

[0275] In some embodiments, the positive terminal 30 further includes a second positive terminal portion 32 and a third positive terminal portion 33. The second positive terminal portion 32 is located inside the first wall portion 20a and electrically connected to the positive electrode tab 12. At least a portion of the third positive terminal portion 33 is accommodated in the positive electrode lead-out hole 221, and the third positive terminal portion 33 connects the second positive terminal portion 32 and the first positive terminal portion 31. In the thickness direction Z, a portion of the first wall portion 20a is located between the first positive terminal portion 31 and the second positive terminal portion 32.

[0276] The third positive terminal 33 and the first positive terminal 31 can be integrally formed. Alternatively, the third positive terminal 33 and the first positive terminal 31 can also be formed independently and fixedly connected by welding, snap-fitting, bonding or other methods.

[0277] The third positive terminal 33 and the second positive terminal 32 can be integrally formed. Alternatively, the third positive terminal 33 and the second positive terminal 32 can be formed independently and fixedly connected by welding, snap-fitting, bonding or other methods.

[0278] The third positive terminal part 33 can be one or more.

[0279] The third positive terminal 33 and the first positive terminal 31 may be made of the same material or different materials.

[0280] The second positive terminal 32 can be directly connected to the positive electrode tab 12, for example, the second positive terminal 32 can be soldered to the positive electrode tab 12. Alternatively, the second positive terminal 32 can also be connected to the positive electrode tab 12 through other conductive structures (e.g., adapter pieces).

[0281] The first wall portion 20a can limit the third positive terminal portion 33 in the radial direction of the positive lead-out hole 221. The first positive terminal portion 31 and the second positive terminal portion 32 can clamp the first wall portion 20a from both sides, thereby achieving fixation in the thickness direction Z.

[0282] In some embodiments, the second positive terminal 32 and the third positive terminal 33 are integrally formed, which can improve the connection strength between the second positive terminal 32 and the third positive terminal 33, reduce resistance, and improve overcurrent capability.

[0283] For example, the third positive terminal portion 33 protrudes from the surface of the second positive terminal portion 32 facing the first wall portion 20a.

[0284] In some embodiments, the first positive terminal portion 31 is provided with a first through hole 314, which extends through the first positive terminal portion 31 along the thickness direction Z of the first wall portion 20a. A portion of the third positive terminal portion 33 is accommodated in the first through hole 314 and connected to the first positive terminal portion 31.

[0285] For example, the first through hole 314 may be a constant diameter hole or a variable diameter hole. For instance, the first through hole 314 may be a stepped hole.

[0286] In the thickness direction Z, the end of the third positive terminal 33 that is away from the second positive terminal 32 may extend beyond the first through hole 314 or may not extend beyond the first through hole 314.

[0287] In the thickness direction Z, the end of the third positive terminal 33 that is away from the second positive terminal 32 may overlap with the first busbar 7a or may not overlap with the first busbar 7a.

[0288] In the thickness direction Z, the end of the third positive terminal 33 that is away from the second positive terminal 32 may overlap with the heat exchanger 9 or may not overlap with the heat exchanger 9.

[0289] During assembly, the third positive terminal 33 can be passed through the positive lead-out hole 221 and the first through hole 314 first, and then the third positive terminal 33 can be connected to the first positive terminal 31. By providing the first through hole 314, the assembly process can be simplified.

[0290] In some embodiments, the first positive terminal 31 and the second positive terminal 32 are both flat plates. The third positive terminal 33 is columnar.

[0291] In some embodiments, the third positive terminal portion 33 is riveted to the first positive terminal portion 31.

[0292] In some embodiments, in the thickness direction Z of the first wall portion 20a, the end of the third positive terminal portion 33 away from the second positive terminal portion 32 does not extend beyond the first through hole 314, so as to reduce the risk that the third positive terminal portion 33 interferes with the connection between the first positive terminal portion 31 and other components (such as the first busbar component 7a or the heat exchanger 9).

[0293] In some embodiments, the positive terminal 30 includes a plurality of third positive terminal portions 33 spaced apart. By providing a plurality of third positive terminal portions 33, the current carrying capacity can be improved, heat generation can be reduced, the structural strength of the positive terminal 30 can be improved, and the stability of the connection between the positive terminal 30 and the first wall portion 20a can be enhanced.

[0294] In some embodiments, there are multiple positive lead-out holes 221, and the multiple positive lead-out holes 221 are configured to correspond one-to-one with multiple third positive terminal portions 33.

[0295] In some embodiments, the first portion 311 is connected to the second positive terminal portion 32 via at least one third positive terminal portion 33, and the second portion 312 is connected to the second positive terminal portion 32 via at least one third positive terminal portion 33.

[0296] Connecting the first portion 311 to the third positive terminal portion 33 improves the stability of the first portion 311. When the battery cell 6 is subjected to external impact, the third positive terminal portion 33 can limit the deformation of the first portion 311, thereby reducing the risk of connection failure between the first portion 311 and the first busbar component 7a. In addition, connecting the first portion 311 to the third positive terminal portion 33 can also shorten the conductive path between the first busbar component 7a and the positive electrode tab 12, reducing resistance.

[0297] By connecting the second part 312 to the third positive terminal 33, the third positive terminal 33 can limit the deformation of the second part 312 when the battery cell 6 is subjected to external impact, thereby reducing the stability of the heat exchange interface between the second part 312 and the heat exchanger 9. In addition, connecting the second part 312 to the third positive terminal 33 can also shorten the heat transfer path between the heat exchanger 9 and the positive electrode tab 12, reducing resistance.

[0298] In some embodiments, the first positive terminal portion 31 includes a first edge 31c and a second edge 31d disposed opposite to each other along a first direction X, the first direction X being parallel to the length direction of the first wall portion 20a. The first positive terminal portion 31 is provided with two first through holes 314 spaced apart along the first direction X, and two third positive terminal portions 33 respectively pass through the two first through holes 314 and are connected to the first positive terminal portion 31. In the first direction X, the distance between the first edge 31c and the axis of the first through hole 314 near the first edge 31c is D1, the distance between the second edge 31d and the axis of the first through hole 314 near the second edge 31d is D2, and the distance between the axes of the two first through holes 314 is D3. D1 / D2 is 0.9-1.1, and (D1+D2) / D3 is 0.9-1.1.

[0299] As an example, D1 / D2 is 0.9, 0.95, 1, 1.05, or 1.1.

[0300] As an example, (D1+D2) / D3 is 0.9, 0.95, 1, 1.05, or 1.1.

[0301] Viewed from the thickness direction Z, the two third positive terminal parts 33 are approximately symmetrically arranged, which can improve the stability of the first positive terminal part 31 and increase the structural strength of the positive terminal 30.

[0302] In some embodiments, D1 = D2, and optionally, D3 = 2 × D1.

[0303] In some embodiments, the cross section of the third positive end portion 33 in the thickness direction Z perpendicular to the first wall portion 20a is circular, elliptical, or racetrack-shaped.

[0304] In some examples, the cross-section of the third positive terminal 33 is circular, and correspondingly, the positive lead-out hole 221 is a circular hole. The circular third positive terminal 33 is easy to process and form; the positive lead-out hole 221 can be sealed by a circular sealing ring, and the deformation of the circular sealing ring is uniform, resulting in a good sealing effect.

[0305] In other examples, the cross-section of the third positive terminal 33 is racetrack-shaped, and correspondingly, the positive lead-out hole 221 is racetrack-shaped. The racetrack-shaped third positive terminal 33 can have a larger cross-sectional area than a circular third positive terminal 33, thereby improving its current-carrying capacity. Of course, the circular third positive terminal 33 is easier to manufacture than the racetrack-shaped one.

[0306] In some other examples, the cross-section of the third positive terminal 33 is elliptical.

[0307] In some embodiments, the positive electrode tab 12 is soldered to the second positive electrode portion 32 to form a first solder mark 80a.

[0308] By directly welding the positive electrode tab 12 to the second positive terminal portion 32, the conductive path between the positive electrode tab 12 and the second positive terminal portion 32 can be shortened, the resistance can be reduced, and the heat generation of the positive electrode tab 12 and the second positive terminal portion 32 can be reduced.

[0309] In some embodiments, the positive electrode tab 12 is connected to the second positive electrode portion 32 by laser welding or ultrasonic welding.

[0310] In some embodiments, the first solder mark 80a is configured to at least partially overlap with the heat exchanger 9 of the battery in the thickness direction Z of the first wall portion 20a.

[0311] When current passes through the first solder mark 80a, the first solder mark 80a generates heat. The embodiments of this application can reduce the distance between the first solder mark 80a and the heat exchanger 9, thereby improving the heat dissipation efficiency of the first solder mark 80a and reducing the temperature rise of the first solder mark 80a.

[0312] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the first positive terminal portion 31 is greater than the projected area of ​​the second positive terminal portion 32.

[0313] Compared to the second positive terminal 32, the first positive terminal 31 can have a larger area, which can improve the heat dissipation efficiency of the first positive terminal 31; provided that the overcurrent area meets the requirements, the second positive terminal 32 can have a smaller area than the first positive terminal 31, thereby saving internal space of the casing 20 and increasing the energy density of the battery cell 6.

[0314] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area S1 of the first positive end portion 31 is 0.2-0.5 times the projected area S3 of the first wall portion 20a.

[0315] Optionally, S1 / S3 can be 0.2, 0.3, 0.4 or 0.5.

[0316] The ratio of the projected area of ​​the first positive terminal 31 to the projected area of ​​the first wall portion 20a is greater than or equal to 0.2. This allows the first positive terminal 31 to have a larger exposed area for heat dissipation, thereby reducing the temperature rise of the first positive terminal 30 and the positive electrode tab 12, and improving the cycle performance and reliability of the battery cell 6. The ratio of the projected area of ​​the first positive terminal 31 to the projected area of ​​the first wall portion 20a is less than or equal to 0.5, which allows for the provision of installation space for other components of the battery cell 6.

[0317] Limiting S1 / S3 to 0.2-0.5 allows the first positive terminal 31 to reserve a larger area for heat exchange with the heat exchanger 9, thereby improving heat exchange efficiency.

[0318] In some embodiments, viewed from the thickness direction Z, both the first wall portion 20a and the first positive terminal portion 31 are rectangular. The length of the first wall portion 20a is L1, and the width of the first wall portion 20a is W1. The length of the first positive terminal portion 31 is L2, and the width of the first positive terminal portion 31 is W2. (L2×W2) / (L1×W1) is 0.2-0.5.

[0319] It should be noted that the rectangle does not have to be a perfect rectangle; for example, the four corners of the rectangle can be rounded.

[0320] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the second positive end portion 32 is 0.2-0.5 times the projected area of ​​the first wall portion 20a.

[0321] The ratio of the projected area of ​​the second positive terminal 32 to the projected area of ​​the first wall portion 20a is greater than or equal to 0.2. This allows for a larger connection area and current-carrying area between the second positive terminal 32 and the positive electrode tab 12, thereby reducing resistance, heat generation in both the second positive terminal 32 and the positive electrode tab 12, and lowering the temperature rise of the battery cell 6. The ratio of the projected area of ​​the second positive terminal 32 to the projected area of ​​the first wall portion 20a is less than or equal to 0.5, which allows for the provision of installation space for other components inside the housing 20, reducing the risk of interference or short circuits between the second positive terminal 32 and other components, and improving the reliability of the battery cell 6.

[0322] In some embodiments, the first negative terminal sub-part 41 can be used to connect to the second bus component 7b.

[0323] For example, the first negative terminal portion 41 may be disposed close to the heat exchanger 9 to exchange heat with the heat exchanger 9; alternatively, the first negative terminal portion 41 may also be disposed away from the heat exchanger 9 to reduce its heat exchange with the heat exchanger 9.

[0324] In some embodiments, the projected area of ​​the first positive terminal 31 along its own thickness direction is 1.2-5 times the projected area of ​​the first negative terminal 41 along its own thickness direction. Optionally, the projected area of ​​the first positive terminal 31 along its own thickness direction is 2-3 times the projected area of ​​the first negative terminal 41 along its own thickness direction.

[0325] As an example, the projected area of ​​the first positive terminal 31 along its own thickness direction is equal to S1; the projected area of ​​the first negative terminal 41 along its own thickness direction is equal to S2. Optionally, S1 / S2 is 1.2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5.

[0326] Setting S1 / S2 to be greater than or equal to 1.2 allows the first positive terminal 31 to have a larger exposed area, thereby improving the efficiency of heat dissipation from the first positive terminal 31, reducing the heat accumulated on the positive electrode tab 12, and lowering the temperature difference between the positive electrode tab 12 and the negative electrode tab 13. Setting S1 / S2 to be less than or equal to 5 also limits the difference between the heat dissipation area of ​​the first positive terminal 31 and the heat dissipation area of ​​the first negative terminal 41, further reducing the temperature difference between the positive electrode tab 12 and the negative electrode tab 13.

[0327] In addition, limiting S1 / S2 to 1.2-5 can also take into account the current-carrying capacity of the first positive terminal sub-section 31 and the first negative terminal sub-section 41 to a certain extent.

[0328] In some embodiments, the first negative terminal sub-part 41 is generally rectangular, with a length of L3 and a width of W3.

[0329] Optionally, (L2×W2) / (L3×W3) is 1.2-5, or optionally 2-3.

[0330] In some embodiments, both the positive terminal 30 and the negative terminal 40 are disposed on the first wall portion 20a. Along the thickness direction Z of the first wall portion 20a, the projected area of ​​the first positive terminal portion 31 is S1, the projected area of ​​the first negative terminal portion 41 is S2, and the projected area of ​​the first wall portion 20a is S3. S1, S2, and S3 satisfy: 0.2 ≤ (S1 + S2) / S3 ≤ 0.8.

[0331] Setting (S1+S2) / S3 to be greater than or equal to 0.2 allows the first positive terminal 31 and the first negative terminal 41 to have larger areas, thereby improving the heat dissipation and overcurrent capacity of the positive terminal 30 and the negative terminal 40, and improving the cycle performance of the battery cell 6. Setting (S1+S2) / S3 to be less than or equal to 0.8 allows for the provision of installation space for other components and maintains the distance between the first positive terminal 31 and the second positive terminal 32, reducing the risk of short circuits.

[0332] Optionally, (S1+S2) / S3 can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8.

[0333] Optionally, 0.3≤(S1+S2) / S3≤0.5.

[0334] Optionally, S1 / S2 can be 1.5-3, or optionally 2-3.

[0335] In some embodiments, the negative terminal 40 is disposed on the first wall portion 20a. In the thickness direction Z of the first wall portion 20a, the first positive terminal portion 31 overlaps with the heat exchanger 9 of the battery, while the first negative terminal portion 41 does not overlap with the heat exchanger 9.

[0336] Compared to the first negative terminal 41, the first positive terminal 31 is closer to the heat exchanger 9. This can further improve the efficiency of heat dissipation from the first positive terminal 31, reduce the heat accumulated on the positive electrode tab 12, reduce the temperature difference between the positive electrode tab 12 and the negative electrode tab 13, and improve the cycle performance and cycle life of the battery cell 6.

[0337] In addition, if the heat exchange efficiency between the heat exchanger 9 and the first positive terminal 31 meets the requirements, the heat exchanger 9 may not need to exchange heat with the first negative terminal 41. This can reduce the volume of the heat exchanger 9, reduce the difficulty of its installation, and increase the energy density of the battery 2.

[0338] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the second portion 312 is greater than the projected area of ​​the first negative terminal portion 41. Optionally, the projected area of ​​the second portion 312 is 1.5 to 3 times the projected area of ​​the first negative terminal portion 41.

[0339] In some embodiments, the housing 20 is provided with a negative electrode lead-out hole 222.

[0340] The negative electrode lead-out hole 222 can be provided in the first wall portion 20a, the second wall portion 20b, or other wall portions of the housing 20. As an example, the negative electrode lead-out hole 222 is provided in the first wall portion 20a and extends through the first wall portion 20a in the thickness direction Z.

[0341] There can be one or more negative electrode lead-out holes 222.

[0342] The negative electrode lead-out hole 222 can be a round hole, a rectangular hole, an elliptical hole, a racetrack-shaped hole, or other shapes.

[0343] By providing a negative lead-out hole 222, an electrical connection can be made between the first negative terminal 41 and the negative terminal tab 13.

[0344] In some embodiments, the negative terminal 40 further includes a first negative terminal portion 41, a second negative terminal portion 42, and a third negative terminal portion 43. The first negative terminal portion 41 is located on the outside of the housing 20, the second negative terminal portion 42 is located on the inside of the housing 20 and is electrically connected to the negative electrode tab 13, and at least a portion of the third negative terminal portion 43 is accommodated in the negative electrode lead-out hole 222, and the third negative terminal portion 43 connects the second negative terminal portion 42 and the first negative terminal portion 41.

[0345] The third negative terminal 43 and the first negative terminal 41 can be integrally formed. Alternatively, the third negative terminal 43 and the first negative terminal 41 can also be formed independently and fixedly connected by welding, snap-fitting, bonding or other methods.

[0346] The third negative terminal 43 and the second negative terminal 42 can be integrally formed. Alternatively, the third negative terminal 43 and the second negative terminal 42 can be formed independently and fixedly connected by welding, snap-fitting, bonding or other methods.

[0347] The third negative extreme sub-part 43 can be one or more.

[0348] The third negative terminal 43 and the first negative terminal 41 may be made of the same material or different materials.

[0349] The second negative terminal 42 can be directly connected to the negative electrode tab 13, for example, the second negative terminal 42 is soldered to the negative electrode tab 13 and forms a second solder mark 80b. Alternatively, the second negative terminal 42 can also be connected to the negative electrode tab 13 through other conductive structures (e.g., adapter tabs).

[0350] In some embodiments, the third negative terminal 43 and the second negative terminal 42 are integrally formed, which can improve the connection strength between the third negative terminal 43 and the second negative terminal 42, reduce resistance, and improve overcurrent capability.

[0351] In some embodiments, the first negative terminal 41 is provided with a second through hole 414, which extends through the first negative terminal 41. A portion of the third negative terminal 43 is accommodated in the second through hole 414 and connected to the first negative terminal 41.

[0352] For example, the second through hole 414 may be a constant diameter hole or a variable diameter hole. For instance, the second through hole 414 may be a stepped hole.

[0353] The end of the third negative terminal 43 that is away from the second positive terminal 32 may extend beyond the second through hole 414 or may not extend beyond the second through hole 414.

[0354] During assembly, the third negative terminal 43 can be passed through the negative lead-out hole 222 and the second through hole 414 first, and then the third negative terminal 43 can be connected to the first negative terminal 41. The assembly process can be simplified by providing the second through hole 414.

[0355] In some embodiments, the first negative terminal 41 and the second negative terminal 42 are both flat. The third negative terminal 43 is columnar.

[0356] In some embodiments, the third negative terminal portion 43 is riveted to the first negative terminal portion 41.

[0357] In some embodiments, in the axial direction of the negative lead-out hole 222, the end of the third negative terminal 43 away from the second negative terminal 42 does not extend beyond the second through hole 414, so as to reduce the risk of the third negative terminal 43 interfering with the connection between the first negative terminal 41 and other components (e.g., the second busbar component 7b).

[0358] Optionally, the negative terminal 40 is disposed on the first wall portion 20a, and the axial direction of the negative terminal lead-out hole 222 is parallel to the thickness direction Z of the first wall portion 20a.

[0359] In some embodiments, the negative terminal 40 includes a third negative terminal portion 43. The first negative terminal portion 41 and the second negative terminal portion 42 may have a small area. Therefore, using a third negative terminal portion 43 can stably connect the first negative terminal portion 41 and the second negative terminal portion 42, thereby simplifying the structure of the negative terminal 40 and reducing the volume of the negative terminal 40.

[0360] The first positive terminal 31, the second positive terminal 32, and the third positive terminal 33 all include the same base metal. The base metal is the metal with the highest content in the composition. For example, the base metal of the first positive terminal 31, the second positive terminal 32, and the third positive terminal 33 is aluminum. For instance, the first positive terminal 31 is made of aluminum or an aluminum alloy, the second positive terminal 32 is made of aluminum or an aluminum alloy, and the third positive terminal 33 is made of aluminum or an aluminum alloy.

[0361] The base metal of the second positive terminal 32 is the same as the base metal of the positive electrode tab 12.

[0362] The second negative terminal portion 42 and the third negative terminal portion 43 include the same base metal. For example, the base metal of the second negative terminal portion 42 and the third negative terminal portion 43 is copper. For example, the material of the second negative terminal portion 42 is copper or a copper alloy, and the material of the third negative terminal portion 43 is copper or a copper alloy.

[0363] The base metal of the third negative electrode part 43 is the same as the base metal of the negative electrode tab 13.

[0364] The first negative terminal portion 41 may include a first plate 41e and a second plate 41f. The second plate 41f is fixed to the first plate 41e, and a second through hole 414 passes through the second plate 41f and the first plate 41e. As an example, the first plate 41e is provided with a groove, and the second plate 41f is accommodated in the groove.

[0365] The base metal of the first plate 41e is different from the base metal of the second plate 41f. The base metal of the second plate 41f is the same as the base metal of the third negative terminal 43. Optionally, the first negative terminal 41 is a copper-aluminum composite plate.

[0366] The base metal of the first plate 41e is the same as the base metal of the second busbar component 7b, which facilitates soldering. The base metal of the first positive terminal 31 is the same as the base metal of the first busbar component 7a, which facilitates soldering. The first busbar component 7a and the second busbar component 7b are made of the same material.

[0367] Optionally, in the first direction X, the length of the positive electrode tab 12 is greater than the length of the negative electrode tab 13. By increasing the length of the positive electrode tab 12, the current-carrying area of ​​the positive electrode tab 12 can be increased, the resistance of the positive electrode tab 12 can be reduced, the heat generation of the aluminum positive electrode tab 12 can be reduced, and the temperature difference between the positive electrode tab 12 and the negative electrode tab 13 can be reduced.

[0368] Optionally, in the first direction X, the ratio of the length of the positive electrode tab 12 to the length of the first wall portion 20a is 0.3-0.5.

[0369] Optionally, the area of ​​the first solder mark 80a is larger than the area of ​​the second solder mark 80b.

[0370] Optionally, the length of the first solder mark 80a is greater than the length of the second solder mark 80b.

[0371] In some embodiments, the projected area of ​​the second positive terminal portion 32 along its own thickness direction is greater than the projected area of ​​the second negative terminal portion 42 along its own thickness direction.

[0372] Compared to the second negative terminal 42, the second positive terminal 32 can have a larger flow area, thereby reducing the heat generation of the second positive terminal 32 and the positive electrode tab 12, reducing the temperature difference between the positive electrode tab 12 and the negative electrode tab 13, and improving the cycle performance of the battery cell.

[0373] Furthermore, the first positive terminal portion 31 has a large area to facilitate heat exchange with the heat exchanger 9. Setting the second positive terminal portion 32 to have a large area reduces the strength difference between the first positive terminal portion 31 and the second positive terminal portion 32, decreases the deformation of the second positive terminal portion 32 when the battery cell 6 is subjected to external impact, and improves the stability of fixing the positive terminal 30 to the first wall portion 20a.

[0374] As an example, the base metal of the second positive terminal 32 is aluminum, and the base metal of the second negative terminal 42 is copper. By increasing the area of ​​the second positive terminal 32, the difference in current-carrying capacity between the second positive terminal 32 and the second negative terminal 42 can be reduced.

[0375] In some embodiments, the projected area of ​​the second positive terminal 32 along its own thickness direction is 1.2 to 5 times the projected area of ​​the second negative terminal 42 along its own thickness direction.

[0376] Optionally, the projected area of ​​the second positive terminal 32 along its own thickness direction is 1.2 times, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, or 5 times the projected area of ​​the second negative terminal 42 along its own thickness direction.

[0377] Optionally, the projected area of ​​the second positive terminal 32 along its own thickness direction is 2-3 times the projected area of ​​the second negative terminal 42 along its own thickness direction.

[0378] The embodiments of this application can, to a certain extent, balance the overcurrent capacity of the positive terminal 30 and the overcurrent capacity of the negative terminal 40, thereby improving the cycle performance of the battery cell 6.

[0379] In some embodiments, the battery cell 6 can be charged at a charging rate of 2C-6C.

[0380] In some embodiments, under room temperature conditions, the charging time for a single battery cell 6 to charge from 10% SOC to 80% SOC is less than or equal to 10.5 minutes.

[0381] As an example, room temperature can be an ambient temperature of 30°C.

[0382] SOC refers to the state of charge of a single battery cell.

[0383] For example, 100% SOC and 0% SOC are defined as follows: charging battery cell 6 at a constant current charging rate of 0.33C to the upper limit voltage of the battery charging, and then charging it at a constant voltage rate of 0.05C, corresponds to the state of 100% SOC of the battery cell; discharging battery cell 6 at a constant current discharging rate of 0.33C to the cutoff voltage corresponds to the state of 0% SOC of the battery cell. For example, the upper limit voltage of the battery charging and the cutoff voltage are marked on the packaging film of the battery cell.

[0384] For example, the charging time of battery cell 6 from 10% SOC to 80% SOC is 10.5 min, 10 min, 9.5 min, 9 min, 8.5 min, 8 min, 7.5 min, 7 min, 6.5 min, 6 min, 5.5 min, 5 min, or any combination of two of the above values.

[0385] In this embodiment, the battery cell 6 has fast charging capability, which can save charging time and improve user experience. During the fast charging process of the battery cell 6, the first positive terminal can exchange heat with the heat exchanger, thereby reducing the temperature rise of the battery cell 6 and reducing the risk of thermal runaway of the battery cell.

[0386] Figure 12 is a structural schematic diagram of an end cap assembly provided in some other embodiments of this application; Figure 13 is a top view schematic diagram of the end cap assembly shown in Figure 12. As an example, in Figure 13, the first region and the second region are shown by diagonal lines.

[0387] Referring to Figures 12 and 13, in some embodiments, the first region 31a and the second region 31b are flush. Embodiments of this application can reduce the molding difficulty of the first positive terminal portion 31 and improve the flatness of the first positive terminal portion 31.

[0388] In some embodiments, the surface of the first positive terminal portion 31 away from the first wall portion 20a may be a plane.

[0389] In some embodiments, the first positive end portion 31 is a rectangular flat plate structure.

[0390] In some embodiments, the area of ​​the second region 31b is larger than the area of ​​the first region 31a.

[0391] In some embodiments, the positive terminal 30 includes two third positive terminal portions 33.

[0392] In some embodiments, the first positive terminal portion 31 is symmetrical about a plane perpendicular to the first direction X.

[0393] In some embodiments, the first negative end portion 41 does not overlap with the heat exchanger in the thickness direction Z.

[0394] In some embodiments, the projected area of ​​the first positive terminal 31 along its own thickness direction is 2 to 4 times the projected area of ​​the first negative terminal 41 along its own thickness direction.

[0395] In some embodiments, W2 equals W3.

[0396] In some embodiments, L2 / L3 is 2-5, and optionally 3-4.

[0397] Figure 14 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application.

[0398] Referring to FIG14, in some embodiments, the first portion 311 and the second portion 312 are disposed along the first direction X, the dimension W21 of the first portion 311 along the second direction Y is smaller than the dimension W22 of the second portion 312 along the second direction Y, and the thickness direction Z, the first direction X and the second direction Y of the first wall portion 20a are perpendicular to each other.

[0399] The thickness of the first part 311 may be greater than, equal to or less than the thickness of the second part 312.

[0400] In the first direction X, the size of the first part 311 can be greater than, equal to or less than the size of the second part 312.

[0401] The second portion 312 has a larger dimension in the second direction Y, which increases the heat dissipation area of ​​the second portion 312, reduces the temperature rise of the positive terminal 30 and the positive electrode tab 12, and improves the cycle performance of the battery cell 6. The thickness of the second portion 312 is small, so increasing the dimension of the second portion 312 in the second direction Y has a smaller impact on the energy density of the battery cell compared to increasing the dimension of the first portion 311 in the second direction Y.

[0402] In addition, the second part 312 has a larger dimension in the second direction Y, which can increase the heat exchange area between the second part 312 and the heat exchange element, further improving the heat exchange efficiency.

[0403] In some embodiments, the thickness of the second portion 312 is less than the thickness of the first portion 311. Optionally, the first positive terminal portion 31 is provided with a first recess 313, which is recessed relative to the surface of the first portion 311 away from the first wall portion 20a.

[0404] In some embodiments, the dimension L22 of the second portion 312 along the first direction X may be larger than the dimension L21 of the first portion 311 along the first direction X, so as to further increase the heat exchange area.

[0405] In some embodiments, the dimension W22 of the second portion 312 in the second direction Y is greater than the width W3 of the first negative terminal portion 41.

[0406] Optionally, the dimension W21 of the first part 311 in the second direction Y is equal to the width W3 of the first negative end part 41.

[0407] Figure 15 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application.

[0408] Referring to FIG15, in some embodiments, the first portion 311 and the second portion 312 are spaced apart along a first direction X, which is perpendicular to the thickness direction Z of the first wall portion 20a.

[0409] The first part 311 and the second part 312 can be molded independently, which is beneficial for the processing and molding of the parts. It can also get rid of the size limitations caused by manufacturing capacity limitations, and provide a larger area for the second part 312, thereby improving the heat dissipation effect.

[0410] In some embodiments, the first portion 311 is connected to the second positive terminal portion via at least one third positive terminal portion 33, and the second portion 312 is connected to the second positive terminal portion via at least one third positive terminal portion 33.

[0411] The two third positive terminal portions 33 can respectively fix the first portion 311 and the second portion 312 to the first wall portion 20a to keep the relative positions of the first portion 311 and the second portion 312 fixed.

[0412] In some embodiments, the thickness of the second portion 312 may be less than the thickness of the first portion 311.

[0413] Optionally, the surface of the first portion 311 facing the first wall portion 20a is flush with the surface of the second portion 312 facing the first wall portion 20a.

[0414] In some embodiments, the first part 311 and the second part 312 have the same shape and size. The first part 311 and the second part 312 are the same component, which can save costs and reduce assembly difficulty.

[0415] In some embodiments, the area of ​​the second portion 312 is larger than the area of ​​the first negative terminal portion 41.

[0416] Figure 16 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application; Figure 17 is a cross-sectional schematic diagram of the end cap assembly shown in Figure 16.

[0417] Referring to FIG16, in some embodiments, the first positive terminal portion 31 is configured such that it at least partially overlaps with the heat exchanger of the battery in the thickness direction Z of the first wall portion. The third positive terminal portion 33 is configured such that it does not overlap with the heat exchanger 9 in the thickness direction Z.

[0418] By avoiding the arrangement of the third positive terminal 33 and the heat exchanger, the risk of interference between the third positive terminal 33 and the heat exchanger can be reduced, and the flatness of the heat exchange interface between the first positive terminal 31 and the heat exchanger can be improved.

[0419] In some embodiments, there is one first through hole 314.

[0420] In some embodiments, the first region 31a and the second region 31b are located on both sides of the first through hole 314 along the first direction X.

[0421] In some embodiments, the first positive terminal portion 31 includes a first edge 31c and a second edge 31d disposed opposite to each other along a first direction X, the first direction X being parallel to the length direction of the first wall portion 20a. In the first direction X, the minimum distance D4 between the axis of the first through hole 314 and the first edge 31c is equal to the minimum distance D5 between the axis of the first through hole 314 and the second edge 31d.

[0422] In this embodiment, the first through hole 314 and the third positive terminal 33 are centrally located, which can improve the structural strength of the positive terminal 30 and reduce the risk of deformation of the first positive terminal 31.

[0423] In some embodiments, the first negative terminal 41 is used to connect the second busbar component 7b of the battery and exchange heat with the heat exchanger 9 of the battery.

[0424] During the cycling process of battery 2, both the first positive terminal 31 and the first negative terminal 41 can exchange heat with the heat exchanger, thereby further improving the heat dissipation capacity of the battery cell 6, reducing the temperature rise of the battery cell 6, improving the cycle performance and cycle life of the battery cell 6, and reducing the risk of thermal runaway of the battery cell 6 during fast charging. The negative terminal 40 is connected to the negative electrode tab, and the heat from the negative electrode tab can also be conducted to the heat exchanger through the first negative terminal 41, thereby reducing the temperature rise of the electrode assembly and improving the cycle performance and cycle life of the battery cell 6. The first negative terminal 41 can simultaneously serve the functions of heat dissipation and current transmission, which helps to shorten the heat transfer path between the heat source and the heat exchanger, and improve heat dissipation efficiency.

[0425] In some embodiments, the surface of the first negative terminal portion 41 away from the housing 20 is configured to connect with the heat exchanger. As an example, the surface of the first negative terminal portion 41 away from the housing 20 can be a flat surface or a stepped surface.

[0426] In some embodiments, the negative terminal 40 is disposed on the first wall portion 20a. The second solder mark 80b is configured to at least partially overlap with the heat exchanger in the thickness direction Z of the first wall portion 20a.

[0427] In some embodiments, the negative terminal 40 is disposed on the first wall portion 20a. The surface of the first negative terminal portion 41 away from the first wall portion 20a includes a third region 41a and a fourth region 41b. The third region 41a is configured to overlap and connect with the second busbar 7b in the thickness direction Z. The fourth region 41b is configured to overlap with the heat exchanger 9 in the thickness direction Z.

[0428] As an example, the third region 41a is fitted to the second busbar component.

[0429] As an example, in the thickness direction Z, the projection of the fourth region 41b lies within the projection of the heat exchanger.

[0430] The third region 41a and the fourth region 41b can be flush or misaligned in the thickness direction Z of the first wall 20a.

[0431] The third region 41a and the fourth region 41b can be directly connected or set at intervals.

[0432] In some embodiments, the area of ​​the fourth region 41b is larger than the area of ​​the third region 41a. The larger area of ​​the fourth region 41b can improve the heat exchange efficiency between the heat exchanger and the first negative terminal 41, reduce the temperature rise of the first negative terminal 41, and improve the cycle performance and reliability of the battery cell 6.

[0433] In some embodiments, the third region 41a and the fourth region 41b are located on both sides of the second through hole 414 along the first direction X.

[0434] In some embodiments, the first negative terminal portion 41 has a third edge 41c and a fourth edge 41d at both ends along the first direction X, and in the second direction Y, the minimum distance between the axis of the second through hole 414 and the third edge 41c is equal to the minimum distance between the axis of the second through hole 414 and the fourth edge 41d.

[0435] In some embodiments, the area of ​​the second region 31b is larger than the area of ​​the fourth region 41b. Both the positive electrode tab and the positive terminal 30 are made of copper, while the negative electrode tab and a portion of the negative terminal 40 are made of copper. The positive electrode tab and the positive terminal 30 generate more heat. Setting the second region 31b to be larger than the fourth region 41b can improve the heat exchange efficiency between the positive terminal 30 and the heat exchange element, and reduce the temperature difference between the positive and negative electrode tabs.

[0436] In some embodiments, (L2×W2) / (L3×W3) is 1.2-5, and can be 2-3.

[0437] In some embodiments, the first region 31a, the second region 31b, the fourth region 41b, and the third region 41a are arranged at intervals along the first direction X, which is perpendicular to the thickness direction Z.

[0438] The second region 31b and the fourth region 41b are arranged adjacent to each other along the first direction X. The same heat exchanger can exchange heat with both the second region 31b and the fourth region 41b at the same time, thereby simplifying the structure of the battery.

[0439] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the first negative end portion 41 is 0.2-0.5 times the projected area of ​​the first wall portion 20a.

[0440] Figure 18 is a top view of the end cap assembly of a battery cell provided in some other embodiments of this application.

[0441] Referring to FIG18, in some embodiments, the second region 31b, the first region 31a, the third region 41a and the fourth region 41b are arranged sequentially at intervals along the first direction X, and the first direction X is perpendicular to the thickness direction Z.

[0442] When multiple battery cells 6 are arranged along the first direction X, the second region 31b of one battery cell 6 is adjacent to the fourth region 41b (or the second region 31b) of another battery cell 6. The same heat exchanger can exchange heat with two battery cells 6 at the same time, thereby simplifying the structure of the battery 2.

[0443] In some embodiments, in the first direction X, the minimum distance D5 between the axis of the first through hole 314 and the first edge 31c is less than the minimum distance D4 between the axis of the first through hole 314 and the second edge 31d. The portion of the first positive terminal portion 31 located between the first edge 31c and the first through hole 314 is used to connect with the first busbar component 7a of the battery, and the portion of the first positive terminal portion 31 located between the second edge 31d and the first through hole 314 is used to exchange heat with the heat exchanger 9 of the battery.

[0444] For example, at least a portion of the first region 31a is located between the first edge 31c and the first through hole 314, and at least a portion of the second region 31b is located between the second edge 31d and the first through hole 314.

[0445] In this embodiment, the first through-hole 314 is designed eccentrically, which allows for a larger area to exchange heat with the heat exchanger, thereby improving heat exchange efficiency. This embodiment also reduces the distance between the third positive terminal 33 and the first busbar component, shortening the conductive path, reducing resistance, and decreasing heat generation.

[0446] In some embodiments, in the first direction X, the minimum distance between the axis of the second through hole 414 and the third edge 41c is less than the minimum distance between the axis of the second through hole 414 and the fourth edge 41d. The portion of the first negative terminal portion 41 located between the third edge 41c and the second through hole 414 is used to connect with the second busbar component 7b of the battery, and the portion of the first negative terminal portion 41 located between the fourth edge 41d and the second through hole 414 is used to exchange heat with the heat exchanger 9 of the battery.

[0447] Figure 19 is a schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application.

[0448] Referring to FIG19, in some embodiments, the negative terminal 40 includes a plurality of third negative terminal portions 43 spaced apart. By providing a plurality of third negative terminal portions 43, the current carrying capacity can be improved, heat generation can be reduced, the structural strength of the negative terminal 40 can be improved, and the stability of the connection between the negative terminal 40 and the housing 20 can be enhanced.

[0449] In some embodiments, there are multiple negative electrode leads, and each of the multiple negative electrode leads is provided in a one-to-one correspondence with a multiple third negative electrode portion 43.

[0450] In some embodiments, the first negative terminal sub-section 41 includes a third portion 411 and a fourth portion 412, wherein the third portion 411 is used to connect to the second busbar component and the fourth portion 412 is used to exchange heat with the heat exchanger.

[0451] The thickness of the third part 411 and the thickness of the fourth part 412 can be the same or different.

[0452] In the first direction X, the dimensions of the third part 411 and the fourth part 412 may be the same or different; in the second direction Y, the dimensions of the third part 411 and the fourth part 412 may be the same or different.

[0453] Part 3, 411, and Part 4, 412 can be connected or set separately.

[0454] In some embodiments, the third portion 411 is connected to the second negative terminal portion 42 via at least one third negative terminal portion 43, and the fourth portion 412 is connected to the second negative terminal portion 42 via at least one third negative terminal portion 43.

[0455] In some embodiments, the third portion 411 is configured to at least partially overlap and connect with the second busbar in the thickness direction Z of the first wall portion 20a, and the fourth portion 412 is configured to at least partially overlap with the heat exchanger in the thickness direction Z.

[0456] In some embodiments, the second busbar is disposed on the side of the third portion 411 away from the first wall portion 20a and connected to the third portion 411.

[0457] In some embodiments, the heat exchanger is disposed on the side of the fourth portion 412 away from the first wall portion 20a.

[0458] In some embodiments, the third portion 411 includes a third region 41a. The fourth portion 412 includes a fourth region 41b.

[0459] In some embodiments, the thickness of the third portion 411 is greater than or equal to the thickness of the fourth portion 412. Optionally, the thickness of the third portion 411 is greater than the thickness of the fourth portion 412.

[0460] In some embodiments, the thickness of the third portion 411 is greater than or equal to 3 mm.

[0461] In some embodiments, the thickness of the third portion 411 is equal to the thickness of the first portion 311, and the thickness of the fourth portion 412 is equal to the thickness of the second portion 312.

[0462] In some embodiments, the thickness ratio of the third portion 411 to the fourth portion 412 is 1.2-3, and can be selected as 1.2, 1.5, 2, 2.5 or 3.

[0463] In some embodiments, the third portion 411 extends beyond the fourth portion 412 in a direction away from the first wall portion 20a.

[0464] In some embodiments, the first negative terminal portion 41 has a second recess 413 on the side away from the first wall portion 20a, and the fourth portion 412 is the bottom wall of the second recess 413.

[0465] In some embodiments, the second busbar component is laser-welded to the third portion 411.

[0466] In some embodiments, the second recess 413 is located on one side of the third portion 411 along the first direction X. The end of the second recess 413 away from the third portion 411 along the first direction X may extend to the edge of the first negative terminal portion 41.

[0467] In some embodiments, the second recess 413 extends through the first negative terminal portion 41 along the second direction Y.

[0468] In some embodiments, the depth of the second recess 413 is 0.1 mm to 2 mm in the thickness direction Z of the first wall portion 20a.

[0469] In some embodiments, the depth of the second recess 413 is equal to the depth of the first recess 313.

[0470] In some embodiments, when viewed from the thickness direction Z, the area of ​​the fourth portion 412 is larger than the area of ​​the third portion 411, which allows for a larger heat exchange area between the first negative terminal portion 41 and the heat exchanger.

[0471] In some embodiments, the third portion 411 and the fourth portion 412 are disposed along a first direction X, and the dimension of the third portion 411 along the second direction Y is less than or equal to the dimension of the fourth portion 412 along the second direction Y. Optionally, the dimension of the third portion 411 along the second direction Y is less than the dimension of the fourth portion 412 along the second direction Y.

[0472] In some embodiments, the dimension of the third portion 411 along the second direction Y is equal to the dimension of the first portion 311 along the second direction Y. The dimension of the fourth portion 412 along the second direction Y is equal to the dimension of the second portion 312 along the second direction Y.

[0473] In some embodiments, the third portion 411 and the fourth portion 412 may be arranged continuously along the first direction X, or they may be arranged at intervals along the first direction X.

[0474] In some embodiments, the dimension of the third portion 411 along the first direction X is less than or equal to the dimension of the fourth portion 412 along the second direction Y. Optionally, the dimension of the third portion 411 along the first direction X is less than the dimension of the fourth portion 412 along the first direction X.

[0475] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the second portion 312 is greater than or equal to the projected area of ​​the fourth portion 412, and the projected area of ​​the first portion 311 is greater than or equal to the projected area of ​​the third portion 411.

[0476] Optionally, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the second portion 312 is greater than the projected area of ​​the fourth portion 412, and the projected area of ​​the first portion 311 is greater than the projected area of ​​the third portion 411.

[0477] In some embodiments, in the first direction X, the size of the second portion 312 is larger than the size of the fourth portion 412.

[0478] In some embodiments, a first portion 311, a second portion 312, a fourth portion 412, and a third portion 411 are sequentially arranged in the first direction X. The second portion 312 and the fourth portion 412 are arranged adjacent to each other along the first direction X.

[0479] The first part 311 and the third part 411 are respectively disposed at both ends of the first wall portion 20 along the first direction X, so as to facilitate the arrangement of multiple battery cells into groups.

[0480] The same heat exchanger can exchange heat with both the second part 312 and the fourth part 412 simultaneously, thus simplifying the battery structure.

[0481] Figure 20 is a structural schematic diagram of the end cap assembly of a battery cell provided in some other embodiments of this application.

[0482] Referring to FIG20, in some embodiments, the third portion 411 and the fourth portion 412 may be spaced apart along the first direction X.

[0483] Optionally, the third part 411 is connected to the second negative terminal part 42 via a third negative terminal part 43, and the fourth part 412 is connected to the second negative terminal part 42 via a third negative terminal part 43.

[0484] Optionally, both Part 3 411 and Part 4 412 are copper-aluminum composite panels.

[0485] In some embodiments, in the first direction X, the second portion 312, the first portion 311, the third portion 411, and the fourth portion 412 are arranged sequentially. The first portion 311 and the third portion 411 are arranged opposite to each other along the first direction X, which facilitates the arrangement of multiple battery cells into a group.

[0486] When multiple battery cells 6 are arranged along the first direction X, the second part 312 of one battery cell 6 is adjacent to the fourth part 412 (or the second part 312) of another battery cell 6. The same heat exchanger can exchange heat with two battery cells 6 at the same time, thereby simplifying the battery structure.

[0487] In some embodiments, the thickness of the fourth portion 412 is less than the thickness of the third portion 411.

[0488] Figure 21 is a simplified schematic diagram of a battery cell provided in some other embodiments of this application.

[0489] Referring to FIG21, in some embodiments, the housing 20 includes a second wall portion 20b, and the negative terminal 40 is disposed on the second wall portion 20b.

[0490] By placing the positive terminal 30 and the negative terminal 40 on the first wall portion 20a and the second wall portion 20b respectively, the first positive terminal portion 31 and the first negative terminal portion 41 can have a larger area, thereby improving heat dissipation efficiency and overcurrent capacity, and improving the cycle performance of the battery cell 6.

[0491] Placing the positive terminal 30 and the negative terminal 40 at opposite ends of the housing 20 can also reduce the risk of short circuits.

[0492] In some embodiments, the positive terminal 30 includes a first portion 311 and a second portion 312, which are spaced apart along a first direction X.

[0493] In some embodiments, the negative terminal 40 includes a third portion 411 and a fourth portion 412, which are spaced apart along a first direction X.

[0494] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the first positive terminal portion 31 is S1, and the projected area of ​​the first wall portion 20a is S3. S1 and S3 satisfy: 0.2≤S1 / S3≤0.8; optionally, 0.3≤S1 / S3≤0.5.

[0495] Setting S1 / S3 to greater than or equal to 0.3 allows the first positive terminal 31 to have a larger area, thereby improving the heat dissipation and current carrying capacity of the positive terminal 30 and improving the cycle performance of the battery cell 6. Setting S1 / S3 to less than or equal to 0.8 allows for the provision of installation space for other components and reduces the impact of increasing the size of the first positive terminal 31 on the energy density of the battery cell 6.

[0496] In some embodiments, in the thickness direction Z of the first wall portion 20a, the projected area of ​​the first negative terminal portion 41 is S2, and the projected area of ​​the first wall portion 20a is S3. S2 and S3 satisfy: 0.2≤S2 / S3≤0.8; optionally, 0.3≤S2 / S3≤0.5. S2 is less than S1.

[0497] Setting S2 / S3 to greater than or equal to 0.3 allows the first negative terminal 41 to have a larger area, thereby improving the heat dissipation and overcurrent capacity of the negative terminal 40 and enhancing the cycle performance of the battery cell 6. Setting S2 / S3 to less than or equal to 0.8 allows for the provision of installation space for other components and reduces the impact of increasing the size of the first negative terminal 41 on the energy density of the battery cell 6.

[0498] In some embodiments, heat exchangers can be provided on both sides of the battery cell 6. The heat exchanger on one side of the battery cell 6 exchanges heat with the positive terminal 30, and the heat exchanger on the other side of the battery cell 6 exchanges heat with the negative terminal 40.

[0499] Figure 22 is a cross-sectional schematic diagram of a battery provided in some embodiments of this application.

[0500] Referring to FIG22, in some embodiments, the battery 2 includes a battery cell 6, a first busbar 7a, and a heat exchanger 9. The first busbar 7a is connected to a first positive terminal 31. At least a portion of the heat exchanger 9 is located on the side of the first wall 20a opposite to the electrode assembly 10 and exchanges heat with the first positive terminal 31.

[0501] In some embodiments, the battery 2 further includes a second busbar 7b, which is connected to the first negative terminal 41.

[0502] In some embodiments, a portion of the first positive terminal portion 31 is located between the heat exchanger 9 and the first wall portion 20a in the thickness direction Z of the first wall portion 20a.

[0503] The heat exchanger 9 can exchange heat with the first positive terminal 31, thereby improving the heat dissipation efficiency of the battery cell 6 and improving the cycle performance of the battery cell 6.

[0504] In some embodiments, a portion of the first negative end portion 41 is located between the heat exchanger 9 and the first wall portion 20a in the thickness direction Z of the first wall portion 20a.

[0505] The heat exchanger 9 can exchange heat with the first negative terminal 41, thereby improving the heat dissipation efficiency of the battery cell 6 and improving the cycle performance of the battery cell 6.

[0506] In some embodiments, the battery 2 includes a housing 5, a battery cell 6, and a first busbar component 7a housed within the housing 5.

[0507] In some embodiments, a plurality of battery cells 6 are housed within a housing 5.

[0508] In some embodiments, the heat exchanger 9 is disposed outside the housing 5, which can save internal space of the housing 5 and improve space utilization.

[0509] In some embodiments, the heat exchanger 9 exchanges heat with the positive terminal 30 and the negative terminal 40 through the box wall of the box 5.

[0510] In some embodiments, the casing wall is bonded to the first positive terminal portion 31 of the positive terminal 30 by an insulating and thermally conductive adhesive 9a.

[0511] In some embodiments, the casing wall is bonded to the first negative terminal portion 41 of the negative terminal 40 by an insulating and thermally conductive adhesive 9a.

[0512] In some embodiments, a plurality of battery cells 6 are arranged along a first direction X.

[0513] In some embodiments, the heat exchanger 9 is a heat exchange tube extending along the second direction Y.

[0514] For example, in the thickness direction Z of the first wall portion 20a, a heat exchange tube at least partially overlaps with the second portion 312 of a battery cell 6, and the fourth portion 412 of another battery cell 6 at least partially overlaps with it.

[0515] According to some embodiments of this application, this application also provides an electrical device including a battery from any of the above embodiments, the battery being used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize batteries.

[0516] Referring to Figures 3-8 and 19, an embodiment of this application provides a battery cell 6, which includes a housing 20, an electrode assembly 10, a positive terminal 30, and a negative terminal 40.

[0517] The electrode assembly 10 is housed within the housing 20 and includes a positive electrode tab 12 and a negative electrode tab 13.

[0518] The outer casing 20 includes a first wall portion 20a, which is provided with a positive lead-out hole 221 and a negative lead-out hole 222.

[0519] The positive terminal 30 includes a first positive terminal portion 31, a second positive terminal portion 32, and a third positive terminal portion 33. The first positive terminal portion 31 is located outside the first wall portion 20a, the second positive terminal portion 32 is located inside the first wall portion 20a and connected to the positive electrode tab 12, and at least a portion of the third positive terminal portion 33 is accommodated in the positive electrode lead-out hole 221, and the third positive terminal portion 33 connects the second positive terminal portion 32 and the first positive terminal portion 31. In the thickness direction Z of the first wall portion 20a, a portion of the first wall portion 20a is located between the first positive terminal portion 31 and the second positive terminal portion 32.

[0520] The negative terminal 40 includes a first negative terminal portion 41, a second negative terminal portion 42, and a third negative terminal portion 43. The first negative terminal portion 41 is located outside the first wall portion 20a, the second negative terminal portion 42 is located inside the first wall portion 20a and connected to the negative electrode tab 13, and at least a portion of the third negative terminal portion 43 is accommodated in the negative electrode lead-out hole 222, and the third negative terminal portion 43 connects the second negative terminal portion 42 and the first negative terminal portion 41. In the thickness direction Z of the first wall portion 20a, a portion of the first wall portion 20a is located between the first negative terminal portion 41 and the second negative terminal portion 42.

[0521] The first positive terminal portion 31 includes a first portion 311 and a second portion 312 disposed along a first direction X, wherein the thickness of the first portion 311 is greater than the thickness of the second portion 312. The first positive terminal portion 31 has a first recess 313 on the side away from the first wall portion 20a, and the second portion 312 is the bottom wall of the first recess 313. There are two third positive terminal portions 33, which are respectively connected to the first portion 311 and the second portion 312.

[0522] The first negative terminal portion 41 includes a third portion 411 and a fourth portion 412 disposed along a first direction X, wherein the thickness of the third portion 411 is greater than the thickness of the fourth portion 412. The first negative terminal portion 41 has a second recess 413 on the side away from the first wall portion 20a, and the fourth portion 412 is the bottom wall of the second recess 413. There are two third negative terminal portions 43, which are respectively connected to the third portion 411 and the fourth portion 412.

[0523] The first part 311, the second part 312, the fourth part 412 and the third part 411 are set along the first direction X.

[0524] The first part 311 is used to connect to the first busbar 7a of the battery 2, and the third part 411 is used to connect to the second busbar 7b of the battery 2. The second part 312 and the fourth part 412 are used for heat exchange with the heat exchanger 9.

[0525] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0526] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, comprising: a housing including a first wall portion; an electrode assembly accommodated in the housing, the electrode assembly including a positive electrode tab and a negative electrode tab; a positive electrode terminal disposed at the first wall portion and electrically connected to the positive electrode tab, the positive electrode terminal including a first positive electrode terminal portion located outside the first wall portion; and a negative electrode terminal disposed at the housing and electrically connected to the negative electrode tab, the negative electrode terminal including a first negative electrode terminal portion located outside the housing, a projection area of the first positive electrode terminal portion in a thickness direction of the first wall portion being greater than a projection area of the first negative electrode terminal portion in a thickness direction of the housing. The first positive electrode terminal portion is configured to connect to a first busbar of a battery and exchange heat with a heat exchange member of the battery.

2. The battery cell of claim 1, wherein, The first positive electrode terminal portion includes a first portion configured to connect to the first busbar and a second portion configured to exchange heat with the heat exchange member.

3. The battery cell of claim 2, wherein, The first portion is configured to at least partially overlap and connect to the first busbar in the thickness direction of the first wall portion, and the second portion is configured to at least partially overlap the heat exchange member in the thickness direction of the first wall portion.

4. The battery cell of claim 3, wherein, The thickness of the first portion is greater than the thickness of the second portion.

5. The battery cell of claim 3 or 4, wherein, The first portion extends beyond the second portion in a direction away from the first wall portion.

6. The battery cell of any one of claims 3-5, wherein, The first positive electrode terminal portion has a first recess on a side thereof away from the first wall portion, and the second portion is a bottom wall of the first recess.

7. The battery cell of any one of claims 3-6, wherein, In the thickness direction of the first wall portion, the first recess has a depth of 0.1 mm to 2 mm.

8. The battery cell of claim 7, wherein, The first portion and the second portion are disposed in a first direction, a dimension of the first portion in a second direction is less than a dimension of the second portion in the second direction, and the thickness direction of the first wall portion, the first direction, and the second direction are perpendicular to each other.

9. The battery cell of any one of claims 3-8, wherein, The first portion and the second portion are disposed in a first direction, and the first direction is perpendicular to the thickness direction of the first wall portion.

10. The battery cell of any one of claims 3-9, wherein, The first portion and the second portion are disposed in a first direction, and the first direction is perpendicular to the thickness direction of the first wall portion.

11. The battery cell of any one of claims 3-10, wherein, In the first direction, the second portion has a greater dimension than the first portion. A surface of the first positive electrode terminal portion away from the first wall portion is configured to connect to the heat exchange member.

12. The battery cell of any one of claims 2-11, wherein, The surface of the first positive electrode terminal portion away from the first wall portion includes a first area configured to overlap and connect to the first busbar in the thickness direction of the first wall portion and a second area configured to overlap the heat exchange member in the thickness direction of the first wall portion.

13. The battery cell of any one of claims 2-12, wherein, The first area and the second area are spaced apart.

14. The battery cell of claim 13, wherein, The second area has a greater area than the first area.

15. The battery cell of claim 13 or 14, wherein, A ratio of the area of the first area to a projection area of the first positive electrode terminal portion in the thickness direction of the first wall portion is greater than or equal to 1.5%.

16. The battery cell of any one of claims 13-15, wherein, A ratio of the area of the second area to a projection area of the first positive electrode terminal portion in the thickness direction of the first wall portion is greater than or equal to 10%.

17. The battery cell of any one of claims 13-16, wherein, The first wall portion is provided with a positive electrode lead-out hole; 18. The battery cell of any one of claims 1-17, wherein, ​ The positive electrode terminal further includes a second positive electrode terminal portion and a third positive electrode terminal portion, the second positive electrode terminal portion is located inside the first wall portion and is electrically connected to the positive electrode tab, at least a part of the third positive electrode terminal portion is accommodated in the positive electrode lead-out hole, and the third positive electrode terminal portion connects the second positive electrode terminal portion and the first positive electrode terminal portion. In the thickness direction of the first wall portion, a part of the first wall portion is located between the first positive electrode terminal portion and the second positive electrode terminal portion.

19. The battery cell of claim 18, wherein, The second positive electrode terminal portion and the third positive electrode terminal portion are integrally formed.

20. The battery cell of claim 18 or 19, wherein, The first positive electrode terminal portion is provided with a first through hole, the first through hole penetrates the first positive electrode terminal portion in the thickness direction of the first wall portion; A part of the third positive electrode terminal portion is accommodated in the first through hole and connected to the first positive electrode terminal portion.

21. The battery cell of claim 20, wherein, In the thickness direction of the first wall portion, an end of the third positive electrode terminal portion away from the second positive electrode terminal portion does not exceed the first through hole.

22. The battery cell according to claim 20 or 21, wherein The first positive electrode terminal portion is configured to at least partially overlap with a heat exchange member of the battery in the thickness direction of the first wall portion; The third positive electrode terminal portion is configured to not overlap with the heat exchange member in the thickness direction of the first wall portion.

23. The battery cell of any one of claims 20-22, wherein, The first positive electrode terminal portion includes a first edge and a second edge oppositely arranged in a first direction, the first direction being parallel to a length direction of the first wall portion; In the first direction, a minimum distance between an axis of the first through hole and the first edge is equal to a minimum distance between the axis of the first through hole and the second edge; or, in the first direction, a minimum distance between the axis of the first through hole and the first edge is smaller than a minimum distance between the axis of the first through hole and the second edge, the first positive electrode terminal portion being located between the first edge and the first through hole. A part of the first positive electrode terminal portion for connecting with a first bus member of the battery is located between the second edge and the first through hole.

24. The battery cell of any one of claims 18-23, wherein, The positive electrode terminal includes a plurality of third positive electrode terminal portions arranged at intervals.

25. The battery cell of claim 24, wherein, The first positive electrode terminal portion includes a first part and a second part arranged at intervals in a first direction, the first direction being perpendicular to a thickness direction of the first wall portion; The first part is connected to the second positive electrode terminal portion through at least one of the third positive electrode terminal portions, and the second part is connected to the second positive electrode terminal portion through at least one of the third positive electrode terminal portions.

26. The battery cell of claim 24, wherein, The first positive electrode terminal portion includes a first edge and a second edge oppositely arranged in a first direction, the first direction being parallel to a length direction of the first wall portion; The first positive electrode terminal portion is provided with two first through holes arranged at intervals in the first direction, and two third positive electrode terminal portions are respectively arranged in the two first through holes and connected to the first positive electrode terminal portion; In the first direction, the distance between the first edge and the axis of the first through hole near the first edge is D1, the distance between the second edge and the axis of the first through hole near the second edge is D2, and the distance between the axes of the two first through holes is D3; D1 / D2 is 0.9-1.1, and (D1+D2) / D3 is 0.9-1.

1.

27. The battery cell of any one of claims 18-26, wherein, The cross section of the third positive terminal portion perpendicular to the thickness direction of the first wall portion is circular, elliptical or racetrack-shaped.

28. The battery cell of any one of claims 18-27, wherein, The positive tab is welded to the second positive terminal portion and forms a first weld.

29. The battery cell of claim 28, wherein, The first weld is configured to at least partially overlap with a heat exchange member of the battery in the thickness direction of the first wall portion.

30. The battery cell of any one of claims 18-29, wherein, In the thickness direction of the first wall portion, the projected area of the first positive terminal portion is greater than the projected area of the second positive terminal portion.

31. The battery cell of any one of claims 18-30, wherein, In the thickness direction of the first wall portion, the projected area of the second positive terminal portion is 0.2-0.5 times the projected area of the first wall portion.

32. The battery cell of any one of claims 1-31, wherein, In the thickness direction of the first wall portion, the projected area of the first positive terminal portion is 0.2-0.5 times the projected area of the first wall portion.

33. The battery cell of any one of claims 1-32, wherein, The first negative terminal portion is configured to connect a second bus member of the battery and exchange heat with a heat exchange member of the battery.

34. The battery cell of claim 33, wherein, The negative terminal is arranged on the first wall portion. The surface of the first positive terminal portion away from the first wall portion comprises a first region and a second region, and the first region is configured to overlap and connect with a first bus member of the battery in the thickness direction of the first wall portion. The surface of the first negative terminal portion away from the first wall portion comprises a third region and a fourth region, and the third region is configured to overlap and connect with the second bus member in the thickness direction of the first wall portion. The second region and the fourth region are configured to overlap with the heat exchange member in the thickness direction of the first wall portion. The second region, the first region, the third region and the fourth region are arranged in sequence in a first direction. Alternatively, the first region, the second region, the fourth region and the third region are arranged in sequence in the first direction. The first direction is perpendicular to the thickness direction of the first wall portion.

35. The battery cell of any one of claims 1-34, wherein, The shell is provided with a positive lead-out hole and a negative lead-out hole. The positive terminal further comprises a second positive terminal portion and a third positive terminal portion, the second positive terminal portion is located inside the first wall portion and is electrically connected to the positive tab, at least part of the third positive terminal portion is accommodated in the positive lead-out hole, and the third positive terminal portion connects the second positive terminal portion and the first positive terminal portion. The negative terminal further comprises a second negative terminal portion and a third negative terminal portion, the second negative terminal portion is located inside the shell and is electrically connected to the negative tab, at least part of the third negative terminal portion is accommodated in the negative lead-out hole, and the third negative terminal portion connects the second negative terminal portion and the first negative terminal portion. The second positive terminal portion has a projection area along a thickness direction thereof that is greater than a projection area along a thickness direction of the second negative terminal portion.

36. The battery cell of any one of claims 1-35, wherein, The first positive terminal portion has a projection area along a thickness direction thereof that is 1.2-5 times a projection area along a thickness direction of the first negative terminal portion, and optionally, the first positive terminal portion has a projection area along a thickness direction thereof that is 2-3 times a projection area along a thickness direction of the first negative terminal portion.

37. The battery cell of any one of claims 1-36, wherein, The positive terminal and the negative terminal are both arranged on the first wall portion; In a thickness direction of the first wall portion, the first positive terminal portion has a projection area S1, the first negative terminal portion has a projection area S2, and the first wall portion has a projection area S3; S1, S2, and S3 satisfy 0.2≤(S1+S2) / S3≤0.8, and optionally, 0.3≤(S1+S2) / S3≤0.

5.

38. The battery cell of claim 1, wherein, The housing comprises a second wall portion, and the negative terminal is arranged on the second wall portion; In a thickness direction of the first wall portion, the first positive terminal portion has a projection area S1, and the first wall portion has a projection area S3; S1 and S3 satisfy 0.2≤S1 / S3≤0.8, and optionally, 0.3≤S1 / S3≤0.

5.

39. The battery cell of any one of claims 1-38, wherein, The positive tab is made of aluminum, and the negative tab is made of copper. The positive terminal is made of aluminum or an aluminum alloy, and at least a portion of the negative terminal is made of copper or a copper alloy.

40. The battery cell of claim 1, wherein, The negative terminal is arranged on the first wall portion; In a thickness direction of the first wall portion, the first positive terminal portion overlaps with a heat exchange member of the battery, and the first negative terminal portion does not overlap with the heat exchange member.

41. The battery cell of any one of claims 1-40, wherein, The housing comprises a second wall portion, and the battery cell comprises a pressure relief mechanism arranged on the second wall portion.

42. The battery cell of any one of claims 1-41, wherein, The first wall portion is provided with an electrolyte injection hole.

43. The battery cell of any one of claims 1-42, wherein, The housing comprises a housing body and an end cover, the housing body has an opening, and the end cover is connected to the housing body and covers the opening; The end cover is the first wall portion.

44. A battery, comprising: The battery cell according to any one of claims 1-43; a first busbar component connected to the first positive terminal portion; and a heat exchange member, at least a portion of the heat exchange member is located on a side of the first wall portion away from the electrode assembly and exchanges heat with the first positive terminal portion. In a thickness direction of the first wall portion, a portion of the first positive terminal portion is located between the heat exchange member and the first wall portion.

45. The battery of claim 44, wherein, 46. The battery according to claim 44 or 45, further comprising a box body; The battery cell and the first busbar component are accommodated in the box body, and the heat exchange member is arranged outside the box body.

47. An electric device, comprising the battery according to any one of claims 44-46, wherein the battery is used to provide electric energy. ​

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