Battery cell, battery device, and electric device

Abstract

The application provides a battery cell, a battery device and an electric device. The battery cell comprises a shell, an electrode assembly and a first terminal assembly. The shell comprises a wall part provided with a first electrode lead-out hole. The electrode assembly is accommodated in the shell and comprises a first tab. The first terminal assembly is electrically connected to the first tab. The first terminal assembly comprises a first electrode terminal and a first connecting plate. The first electrode terminal comprises a first terminal part, a second terminal part and a third terminal part. The first connecting plate and the first terminal part are located on two sides of the wall part respectively. The second terminal part is located on a side of the first terminal part facing the first connecting plate, and at least part of the second terminal part is accommodated in the first electrode lead-out hole. A surface of the second terminal part away from the first terminal part abuts against the first connecting plate. The third terminal part protrudes from a surface of the second terminal part abutting against the first connecting plate and is connected to the first connecting plate.

Description

Battery cells, battery devices and electrical equipment Technical Field

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

[0004] Summary of the Invention

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

[0006] In a first aspect, embodiments of this application provide a battery cell, which includes a housing, an electrode assembly, and a first terminal assembly. The housing includes a wall portion, and the wall portion has a first electrode lead-out hole. The electrode assembly is housed within the housing and includes a first electrode tab. The first terminal assembly is electrically connected to the first electrode tab. The first terminal assembly includes a first electrode terminal and a first connecting plate. The first electrode terminal includes a first terminal portion, a second terminal portion, and a third terminal portion. The first connecting plate and the first terminal portion are respectively located on opposite sides of the wall portion along the thickness direction of the wall portion; the second terminal portion is located on the side of the first terminal portion facing the first connecting plate, and at least a portion of the second terminal portion is housed in the first electrode lead-out hole. The surface of the second terminal portion away from the first terminal portion abuts against the first connecting plate; the third terminal portion protrudes from the surface of the second terminal portion that abuts against the first connecting plate and is connected to the first connecting plate.

[0007] During the cycling process of a battery cell, current can be conducted between the first electrode terminal and the first connecting plate through the connection between the third terminal portion and the first connecting plate, or through the contact surface between the second terminal portion and the first connecting plate. In this embodiment, by providing a second terminal portion and a third terminal portion protruding from the second terminal portion, the contact area between the first electrode terminal and the first connecting plate can be increased, the resistance of the first terminal assembly can be reduced, the temperature rise during overcurrent can be decreased, the overcurrent capacity can be improved, the cycle performance and cycle life of the battery cell can be improved, and the risk of thermal runaway during fast charging can be reduced.

[0008] In some embodiments, the surface of the second terminal portion that abuts against the first connecting plate surrounds the third terminal portion, which can increase the contact area between the second terminal portion and the first connecting plate, improve the current carrying capacity, and thereby reduce the temperature rise of the first terminal assembly during the cycling process of the battery cell.

[0009] In some embodiments, the first connecting plate is provided with a first through hole; at least a portion of the third terminal portion is accommodated in the first through hole and connected to the first connecting plate. By providing the first through hole, it is convenient to connect the third terminal portion to the first connecting plate from the side opposite to the second terminal portion.

[0010] In some embodiments, the third terminal portion is riveted to the first connecting plate. The riveting method is easy to implement and can provide high connection strength.

[0011] In some embodiments, the third terminal portion does not extend beyond the surface of the first connecting plate away from the wall portion in the direction from the second terminal portion to the third terminal portion. This can save the space occupied by the third terminal portion, reduce the risk of interference between the third terminal portion and other components, and improve the reliability of the battery cell.

[0012] In some embodiments, the area of ​​the minimum cross-section of the second terminal portion perpendicular to the thickness direction of the wall portion is S1, and the area of ​​the minimum cross-section of the third terminal portion perpendicular to the thickness direction is S2. 1.5≤S1 / S2≤25; optionally, 2≤S1 / S2≤10.

[0013] Setting S1 / S2 to greater than or equal to 1.5 increases the contact area between the second terminal and the first connecting plate, improving the current-carrying capacity between them and reducing the temperature rise of the first terminal assembly during battery cell cycling. The third terminal can constrain the first connecting plate, improving the stability of the contact between the second terminal and the first connecting plate. Setting S1 / S2 to less than or equal to 25 reduces the maximum dimensional difference between the second and third terminal portions, allowing the first connecting plate to maintain stable contact with the second terminal portion under the constraint of the third terminal, thereby improving the current-carrying capacity and reducing the risk of connection failure between the first electrode terminal and the first connecting plate.

[0014] In some embodiments, the first connecting plate is located on the side of the wall away from the electrode assembly. The first connecting plate has a first through hole, and at least a portion of the third terminal portion is accommodated in the first through hole and connected to the first connecting plate. By disposing the first connecting plate on the outside of the wall, the connection between the third terminal portion and the first connecting plate can be achieved from the outside of the wall, reducing impurities sputtered to the inside of the wall during the connection process, reducing the risk of impurities falling onto the electrode assembly, and improving the reliability of the battery cell.

[0015] In some embodiments, the first connecting plate and the third terminal portion constitute a lead-out portion, and the area of ​​the lead-out portion projected along the thickness direction of the wall portion is S3; the area of ​​the wall portion projected along the thickness direction is S4. 0.03≤S3 / S4≤0.5; optionally, 0.05≤S3 / S4≤0.2.

[0016] Setting S3 / S4 to greater than or equal to 0.03 allows for a larger lead-out area, thereby improving the lead-out's current-carrying capacity and heat dissipation area, reducing the temperature rise of the first terminal assembly during battery cell cycling, and improving the battery cell's cycle performance. Setting S3 / S4 to less than or equal to 0.5 allows for more space to be reserved for other components, reducing the impact of increasing the lead-out size on the battery cell's energy density.

[0017] In some embodiments, the area of ​​the minimum cross-section of the second terminal portion perpendicular to the thickness direction of the wall portion is S1. The first connecting plate and the third terminal portion constitute a lead-out portion, and the area of ​​the minimum cross-section of the lead-out portion perpendicular to the thickness direction of the wall portion is S5. 0.2≤S1 / S5≤0.8; optionally, 0.3≤S1 / S5≤0.7.

[0018] Setting S1 / S5 to greater than or equal to 0.2 reduces the difference between the current-carrying area of ​​the second terminal and the current-carrying area of ​​the lead-out portion, thereby improving the current-carrying capacity. Setting S1 / S5 to less than or equal to 0.8 allows for a larger overlap area between the lead-out portion and the wall portion, improving the connection strength between the first terminal assembly and the wall portion, reducing the risk of deformation and failure of the lead-out portion when the battery cell is subjected to impact, and improving the reliability of the battery cell.

[0019] In some embodiments, the electrode assembly further includes a second tab, the first tab having the opposite polarity to the second tab. The battery cell also includes a second terminal assembly disposed on the wall portion, the second terminal assembly being electrically connected to the second tab. The wall portion includes a second electrode lead-out hole. The second terminal assembly includes a second electrode terminal and a second connecting plate. The second electrode terminal includes a fourth terminal portion, a fifth terminal portion, and a sixth terminal portion. The second connecting plate and the fourth terminal portion are respectively located on opposite sides of the wall portion. The fifth terminal portion is located on the side of the fourth terminal portion facing the second connecting plate, and at least a portion of the fifth terminal portion is accommodated in the second electrode lead-out hole. The surface of the fifth terminal portion away from the fourth terminal portion abuts against the second connecting plate. The sixth terminal portion protrudes from the surface of the fifth terminal portion abutting against the second connecting plate and is connected to the second connecting plate.

[0020] During the cycling process of a battery cell, current can be conducted between the second electrode terminal and the second connecting plate through the connection between the sixth terminal and the second connecting plate, or through the contact surface between the fifth terminal and the second connecting plate. In this embodiment, by providing a fifth terminal and a sixth terminal protruding from the fifth terminal, the contact area between the second electrode terminal and the second connecting plate can be increased, the resistance of the second terminal assembly can be reduced, the temperature rise during overcurrent can be decreased, the overcurrent capacity can be improved, the cycle performance and cycle life of the battery cell can be improved, and the risk of thermal runaway during fast charging can be reduced.

[0021] In some embodiments, a first connecting plate is located on the side of the wall portion away from the electrode assembly. The first connecting plate includes a first plate portion and a second plate portion connected to the first plate portion. The base metal of the first plate portion is different from the base metal of the second plate portion, and the base metal of the second plate portion is the same as the base metal of the first electrode terminal. A third terminal portion is connected to the second plate portion. In a first direction, at least one end of the second terminal portion protrudes beyond the second plate portion. The portion of the second terminal portion protruding beyond the second plate portion in the first direction abuts against the first plate portion. The first direction is perpendicular to the thickness direction of the wall portion.

[0022] When the materials of the first electrode terminal and the busbar are different, the first connecting plate can act as a connector to improve the connection strength between the first connecting plate and the busbar, and between the first connecting plate and the first electrode terminal, thereby enhancing the current carrying capacity. The base metal of the third terminal portion is the same as the base metal of the second plate portion. Connecting the third terminal portion to the second plate portion reduces the contact resistance between them, improving the current carrying capacity. The second terminal portion protrudes from the second plate portion in the first direction, increasing the current carrying area of ​​the second terminal portion and the contact area between the second terminal portion and the first plate portion. This reduces the resistance of the first terminal assembly, lowers the temperature rise during current carrying, improves the current carrying capacity, and enhances the cycle performance and cycle life of the battery cell.

[0023] In some embodiments, at least a portion of the first plate is disposed between the second terminal portion and the second plate portion in the thickness direction, and abuts against both the second terminal portion and the second plate portion. Embodiments of this application can increase the contact area between the first plate portion and the second plate portion, as well as the contact area between the first plate portion and the second terminal portion, thereby reducing the resistance of the first terminal assembly, reducing the temperature rise during overcurrent, improving overcurrent capability, and enhancing the cycle performance and cycle life of the battery cell.

[0024] In some embodiments, the first tab is soldered to the first terminal portion to form a tab solder portion. In the thickness direction of the wall portion, the tab solder portion at least partially overlaps with the second terminal portion to reduce the conductive path between the tab solder portion and the second terminal portion, reduce resistance, reduce the temperature rise generated during overcurrent, and improve the overcurrent capacity.

[0025] In some embodiments, the maximum dimension of the second terminal portion along the first direction is greater than the maximum dimension of the second terminal portion along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other. Embodiments of this application can increase the dimension of the second terminal portion in the first direction to improve the current-carrying capacity of the second terminal portion.

[0026] In some embodiments, the first direction is parallel to the length direction of the wall portion, and the second direction is parallel to the width direction of the wall portion. This embodiment can effectively utilize the space along the length direction of the wall portion to increase the size of the second terminal portion along the first direction, thereby improving the current-carrying capacity of the second terminal portion.

[0027] In some embodiments, the cross-section of the second terminal portion perpendicular to the thickness direction is elliptical, rectangular, or racetrack-shaped.

[0028] Secondly, embodiments of this application provide a battery device including a plurality of battery cells provided in any of the embodiments of the first aspect.

[0029] In some embodiments, the battery device further includes a busbar component, which is welded to the first terminal assembly to form a welded portion. By providing the welded portion, the connection strength between the busbar component and the first terminal assembly can be improved, the resistance between the busbar component and the first terminal assembly can be reduced, the temperature rise of the first terminal assembly and the busbar component during overcurrent can be reduced, and the cycle performance can be improved.

[0030] In some embodiments, the first connecting plate is located on the side of the wall away from the electrode assembly. The busbar is welded to the first connecting plate and forms at least a portion of the welded portion.

[0031] In some embodiments, the projection of the weld portion and the projection of the second terminal portion at least partially overlap in the thickness direction of the wall portion. Embodiments of this application can shorten the conductive path between the second terminal portion and the weld portion, reduce resistance, lower the temperature rise of the first terminal assembly during overcurrent, improve the cycle performance of the battery cell, and reduce the risk of thermal runaway in the battery cell.

[0032] In some embodiments, the area of ​​the weld portion projected along the thickness direction is S6. The overlapping area between the projection of the weld portion along the thickness direction and the projection of the second terminal portion along the thickness direction is S7. 0.05≤S7 / S6≤1; optionally, 0.4≤S7 / S6≤1. Setting S6 / S7 to be greater than or equal to 0.05 can shorten the conductive path between the second terminal portion and the weld portion, reduce resistance, reduce the temperature rise of the first terminal assembly during overcurrent, improve the cycle performance of the battery cell, and reduce the risk of thermal runaway of the battery cell.

[0033] In some embodiments, the projection of the weld portion is located within the projection of the second terminal portion in the thickness direction of the wall portion. Embodiments of this application can further shorten the conductive path between the second terminal portion and the weld portion, reduce resistance, lower the temperature rise of the first terminal assembly during overcurrent, improve the cycle performance of the battery cell, and reduce the risk of thermal runaway in the battery cell. When welding the first connecting plate and the busbar component, even if the first connecting plate is welded through, the second terminal portion can still prevent the molten pool from melting, reducing the risk of other components of the battery cell being melted through and improving the reliability of the battery cell.

[0034] In some embodiments, the portion of the welded portion that overlaps with the second terminal portion along the thickness direction surrounds the third terminal portion. The portion of the welded portion that overlaps with the second terminal portion along the thickness direction is continuously disposed along the outer periphery of the third terminal portion, which can reduce the conductive path, increase the current-carrying area, and improve the consistency of current flow.

[0035] In some embodiments, the maximum dimension of the second terminal portion along the first direction is greater than the maximum dimension of the second terminal portion along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other. The welding portion includes a first welding portion and a second welding portion spaced apart along the first direction. In the thickness direction, the first welding portion overlaps with one end of the second terminal portion along the first direction, and the second welding portion overlaps with the other end of the second terminal portion along the first direction. The second terminal portion has a larger dimension in the first direction, which increases the current-carrying area of ​​the second terminal portion and reduces the conductive path between the second terminal portion and the first welding portion, as well as between the second terminal portion and the second welding portion, thereby improving the current-carrying capacity.

[0036] In some embodiments, a portion of the weld is formed on the second terminal portion. A portion of the current in the second terminal portion can be conducted to the busbar through the weld, further reducing resistance, lowering the temperature rise of the first terminal assembly during overcurrent, improving the cycle performance of the battery cell, and reducing the risk of thermal runaway in the battery cell. The weld can also improve the connection strength between the first electrode terminal and the first connecting plate, enhance the stability of the contact between the second terminal portion and the first connecting plate, reduce contact resistance, and improve overcurrent capacity.

[0037] In some embodiments, the first connecting plate includes a first portion and a second portion connected to each other, the first portion surrounding and contacting the third terminal portion, and the thickness of the second portion being less than the thickness of the first portion. A busbar abuts against the surface of the second portion away from the second terminal portion, and the busbar, the second portion, and the second terminal portion are welded to form a welded portion.

[0038] Compared to the first part, the second part has a smaller thickness. Connecting the second part to the busbar component reduces welding power, heat generation during welding, and the risk of insulation failure near the first terminal assembly, thus improving the reliability of the battery cell. Compared to the second part, the first part is closer to the third terminal and has a greater thickness. This increases the connection strength between the third terminal and the first connecting plate, reduces deformation of the first connecting plate when connected to the third terminal, and improves reliability.

[0039] Thirdly, embodiments of this application provide an electrical device including a battery device provided in any of the embodiments of the second aspect, the battery device being used to provide electrical energy. Attached Figure Description

[0040] 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.

[0041] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0042] Figure 2 is a schematic diagram of a battery device provided in some embodiments of this application;

[0043] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0044] Figure 4 is a cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0045] Figure 5 is an enlarged view of the area at box A in Figure 4;

[0046] Figure 6 is an enlarged view of the area in box B of Figure 4;

[0047] Figure 7 is an exploded view of the end cap assembly of a battery cell provided in some embodiments of this application;

[0048] Figure 8 is an exploded view of the first terminal assembly of a battery cell provided in some embodiments of this application;

[0049] Figure 9 is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application;

[0050] Figure 10 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of this application;

[0051] Figure 11 is an exploded view of the first terminal assembly of a battery cell provided in some other embodiments of this application;

[0052] Figure 12 is an exploded view of the first terminal assembly of a battery cell provided in some other embodiments of this application;

[0053] Figure 13 is a simplified schematic diagram of a battery device provided in some embodiments of this application;

[0054] Figure 14 is a partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application;

[0055] Figure 15 is a partial cross-sectional schematic diagram of a battery device provided in some other embodiments of this application;

[0056] Figure 16 is a partial cross-sectional schematic diagram of a battery device provided in some other embodiments of this application.

[0057] The annotations in the attached figures are explained as follows:

[0058] 1. Vehicle; 2. Battery unit; 3. Controller; 4. Motor; 5. Housing; 5a. First housing; 5b. Second housing; 6. Battery cell; 7. Busbar assembly;

[0059] 10. Electrode assembly; 11. Electrode body; 12. First electrode tab; 13. Second electrode tab;

[0060] 20. Outer shell; 20a. Wall portion; 21. Housing; 22. End cap; 221. First electrode lead-out hole; 222. Second electrode lead-out hole;

[0061] 30. First terminal assembly; 31. First electrode terminal; 311. First terminal portion; 312. Second terminal portion; 313. Third terminal portion; 32. First connecting plate; 321. First plate portion; 322. Second plate portion; 323. First part; 324. Second part; 325. Third part; 326. Recess; 32a. First through hole; 32b. Second groove; 33. Lead-out portion;

[0062] 40. Second terminal assembly; 41. Second electrode terminal; 42. Second connecting plate; 421. Fourth terminal section; 422. Fifth terminal section; 423. Sixth terminal section; 42a. Second through hole;

[0063] 50. End cap assembly; 60. Insulating component; 70. Pressure relief mechanism;

[0064] W1, electrode tab welding section; W2, welding section; W21, first welding section; W22, second welding section;

[0065] X, first direction; Y, second direction; Z, thickness direction. Detailed Implementation

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] In this application, "multiple" means two or more (including two).

[0073] 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.

[0074] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0075] A battery cell typically includes a casing, an electrode assembly housed within the casing, and a terminal assembly disposed within the casing. The electrode assembly is electrically connected to the terminal assembly, which is used for electrical connection to an external circuit to enable charging or discharging of the battery cell.

[0076] With the development of battery technology, especially its widespread use in daily life, users expect battery devices to charge faster to meet the demands of fast-paced modern life. However, during fast charging, the heat generated by the terminal components increases, causing localized temperature increases in individual battery cells. This affects the cycle performance and cycle life of the battery cells and exacerbates the risk of thermal runaway.

[0077] In view of this, embodiments of this application provide a battery cell that reduces the risk of thermal runaway during fast charging by improving the overcurrent capacity of the terminal assembly, thereby reducing the temperature rise of the battery cell and improving its cycle performance and cycle life.

[0078] The battery cells described in this application are applicable to battery devices and electrical equipment using battery devices. Electrical equipment can be devices that use battery devices as a power source or various energy storage systems that use battery devices as energy storage elements. Electrical equipment can be, but is 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.

[0079] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0080] Figure 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of this application.

[0081] As shown in Figure 1, a battery device 2 is installed inside the vehicle 1. The battery device 2 can be located at the bottom, front, or rear of the vehicle 1. The battery device 2 can be used to power the vehicle 1; for example, the battery device 2 can serve as the operating power source for the vehicle 1.

[0082] The vehicle 1 may also include a controller 3 and a motor 4. The controller 3 is used to control the battery device 2 to supply power to the motor 4, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0083] In some embodiments of this application, the battery device 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.

[0084] Figure 2 is a schematic diagram of a battery device provided in some embodiments of this application.

[0085] Referring to FIG2, in some embodiments, the battery device 2 may include one or more battery cell assemblies for providing voltage and capacity.

[0086] A battery cell assembly may include multiple battery cells 6, which are connected in series, parallel, or mixed connection via a busbar. Mixed connection means that multiple battery cells 6 are connected in both series and parallel.

[0087] Battery cell 6 can be a secondary battery cell. A secondary battery cell refers to a battery cell that can be recharged after being discharged, allowing the active materials to be activated and continue to be used.

[0088] As an 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.

[0089] As an example, the battery cell 6 can be 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.

[0090] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells 6; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells 6 into a single module. As an example, a battery module can be formed by bundling multiple battery cells 6 together with cable ties.

[0091] In some embodiments, the battery device 2 may be a battery pack, which includes a housing 5 and one or more battery cell assemblies housed within the housing 5. As an example, the battery cell assembly may be a battery module, which can be housed within the housing by fixing the battery module to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly fixing multiple battery cells 6 to the housing.

[0092] In some embodiments, the housing 5 is used to house the battery cell 6, and the housing 5 can have various structures.

[0093] In some embodiments, the housing 5 may include a first housing 5a and a second housing 5b. The first housing 5a and the second housing 5b are fastened together to form a closed space inside the housing 5 to house the battery cell assembly. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first housing may be a top cover or a bottom plate.

[0094] In some embodiments, the housing 5 may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the housing to accommodate individual battery cells. As an example, the frame may include multiple side beams.

[0095] 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.

[0096] In some embodiments, the battery device 2 may be an energy storage device.

[0097] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0098] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0099] Figure 3 is a structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 4 is a cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 is an enlarged schematic diagram of Figure 4 at box A; Figure 6 is an enlarged schematic diagram of Figure 4 at box B; Figure 7 is an exploded schematic diagram of the end cap assembly of a battery cell provided in some embodiments of this application; Figure 8 is an exploded schematic diagram of the first terminal assembly of a battery cell provided in some embodiments of this application.

[0100] Referring to Figures 3 to 8, in some embodiments, the battery cell 6 includes a housing 20 and an electrode assembly 10 housed within the housing 20.

[0101] In some embodiments, the outer casing 20 may be a steel casing, an aluminum casing, a plastic casing (such as a polypropylene casing), or a composite metal casing (such as a copper-aluminum composite casing), etc.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0107] 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.

[0108] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0109] 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.

[0110] 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.

[0111] The electrode assembly 10 includes a first electrode, a second electrode, and a separator. The first electrode and the second electrode have opposite polarities, and the separator separates the first electrode and the second electrode.

[0112] One of the first and second electrodes is the positive electrode, and the other is the negative electrode. At least a portion of the separator is located between the positive and negative electrodes. During the charging and discharging of a single battery cell, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0113] The positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector.

[0114] 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.

[0115] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0116] As an example, the positive electrode film layer includes a positive electrode active material; the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0117] In some embodiments, the positive electrode includes a positive tab. Exemplarily, at least a portion of the positive tab is not provided with a positive electrode film layer.

[0118] In some embodiments, the negative electrode may include a negative current collector.

[0119] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] As an example, 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.

[0121] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0122] As an example, the negative electrode film layer includes a negative electrode active material; the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0123] In some embodiments, the negative electrode sheet includes a negative electrode tab; exemplaryly, at least a portion of the negative electrode tab is not provided with a negative electrode film layer.

[0124] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0125] In some embodiments, the separator is a separator membrane. The separator membrane in this application can be any known porous structure separator membrane with good chemical and mechanical stability.

[0126] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component located between the positive and negative electrode plates, or it can be attached to the surface of the positive or negative electrode plate. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0127] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0128] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0129] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0130] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0131] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0132] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0133] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0134] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0135] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0136] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0137] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0138] In some embodiments, the electrode assembly 10 includes an electrode body 11, a first tab 12, and a second tab 13, which extend from the electrode body 11. The first tab 12 and the second tab 13 have opposite polarities; in other words, one of the first tab 12 and the second tab 13 is a positive tab, and the other is a negative tab.

[0139] As an example, the portion of the positive current collector coated with a positive electrode film, the portion of the negative current collector coated with a negative electrode film, the positive electrode film, the negative electrode film, and the separator constitute the electrode body 11. The portion of the positive current collector not coated with a positive electrode film constitutes the positive tab, and the portion of the negative current collector not coated with a negative electrode film constitutes the negative tab. The positive and negative tabs can be led out from the same end of the electrode body 11, or they can be led out from opposite ends of the electrode body 11.

[0140] In some embodiments, the electrode assembly 10 is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0141] In some embodiments, the electrode assembly 10 has a stacked structure.

[0142] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0143] 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.

[0144] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0145] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0146] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0147] In some embodiments, the battery cell 6 includes a first terminal assembly 30 disposed on the housing 20, the first terminal assembly 30 being electrically connected to the first tab 12.

[0148] In some embodiments, the battery cell 6 includes a second terminal assembly 40 disposed on the housing 20, the second terminal assembly 40 being electrically connected to the second tab 13.

[0149] The first terminal assembly 30 and the second terminal assembly 40 are used for electrical connection with an external circuit to enable charging or discharging of the battery cell 6.

[0150] In some embodiments, the first terminal assembly 30 and the second terminal assembly 40 are both disposed on the end cap 22. As an example, the end cap 22, the first terminal assembly 30 and the second terminal assembly 40 can be pre-assembled together and then assembled with the electrode assembly 10 and the housing 21.

[0151] For example, the battery cell 6 includes an end cap assembly 50, which includes an end cap 22, a first terminal assembly 30, and a second terminal assembly 40. Optionally, both the first terminal assembly 30 and the second terminal assembly 40 are insulated from the end cap 22. Optionally, the first terminal assembly 30 is riveted to the end cap 22, and the second terminal assembly 40 is riveted to the end cap 22.

[0152] In some embodiments, the end cap assembly 50 further includes a plurality of insulating members 60 that insulate the first terminal assembly 30 from the end cap 22 and the second terminal assembly 40 from the end cap 22.

[0153] In some embodiments, the battery cell 6 further includes a pressure relief mechanism 70. The pressure relief mechanism 70 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, causing a sudden increase in pressure. In this case, the pressure relief mechanism can be activated to release the internal pressure to the outside, thereby reducing the risk of battery cell explosion and fire.

[0154] For example, a pressure relief mechanism is a component or part that is actuated to release internal gases when the internal pressure or temperature of a battery cell 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.

[0155] The pressure relief mechanism 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 a battery cell reaches a predetermined threshold, the pressure relief mechanism actuates or a weak point in the pressure relief mechanism ruptures, thereby creating an opening or channel for internal pressure release. Alternatively, the pressure relief mechanism can also employ a temperature-sensitive element or structure, that is, when the internal temperature of a battery cell reaches a predetermined threshold, the pressure relief mechanism actuates, thereby creating an opening or channel for internal pressure release.

[0156] When a battery cell experiences thermal runaway, the emissions from the battery cell 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.

[0157] In some embodiments, the pressure relief mechanism 70 is disposed on the housing 20. Exemplarily, the pressure relief mechanism 70 may be disposed on the housing 21 or on the end cap 22.

[0158] In some embodiments, this application provides a battery cell 6, which includes a housing 20, an electrode assembly 10, and a first terminal assembly 30. The housing 20 includes a wall portion 20a, and the wall portion 20a has a first electrode lead-out hole 221. The electrode assembly 10 is housed within the housing 20, and the electrode assembly 10 includes a first tab 12. The first terminal assembly 30 is electrically connected to the first tab 12.

[0159] The first terminal assembly 30 includes a first electrode terminal 31 and a first connecting plate 32. The first electrode terminal 31 includes a first terminal portion 311, a second terminal portion 312, and a third terminal portion 313. The first connecting plate 32 and the first terminal portion 311 are located on opposite sides of the wall portion 20a along the thickness direction Z of the wall portion 20a. The second terminal portion 312 is located on the side of the first terminal portion 311 facing the first connecting plate 32, and at least a portion of the second terminal portion 312 is accommodated in the first electrode lead-out hole 221. The surface of the second terminal portion 312 away from the first terminal portion 311 abuts against the first connecting plate 32. The third terminal portion 313 protrudes from the surface of the second terminal portion 312 that abuts against the first connecting plate 32 and is connected to the first connecting plate 32.

[0160] The wall portion 20a can be an end cap 22 or a wall of the housing 21.

[0161] The first electrode lead-out hole 221 penetrates the wall portion 20a. For example, the first electrode lead-out hole 221 penetrates the wall portion 20a along the thickness direction Z of the wall portion 20a.

[0162] The first electrode lead-out hole 221 can be one or more.

[0163] The first electrode lead-out hole 221 can be a round hole, a rectangular hole, an elliptical hole, a racetrack-shaped hole, or a hole of other shapes.

[0164] The first electrode 12 can be either a positive electrode or a negative electrode. The polarity of the first terminal assembly 30 corresponds to the polarity of the first electrode 12.

[0165] The first terminal assembly 30 and the first tab 12 can be directly connected, or they can be indirectly connected through other conductive structures.

[0166] The first terminal assembly 30 can be one or more.

[0167] In some examples, the first connecting plate 32 may be located on the side of the wall portion 20a facing away from the electrode assembly 10, and the first terminal portion 311 may be located on the side of the wall portion 20a facing the electrode assembly 10; in other words, the first connecting plate 32 may be located on the outer side of the wall portion 20a, and the first terminal portion 311 may be located on the inner side of the wall portion 20a. In other examples, the first connecting plate 32 may be located on the side of the wall portion 20a facing the electrode assembly 10, and the first terminal portion 311 may be located on the side of the wall portion 20a facing away from the electrode assembly 10; in other words, the first connecting plate 32 may be located on the inner side of the wall portion 20a, and the first terminal portion 311 may be located on the outer side of the wall portion 20a.

[0168] The second terminal portion 312 can be entirely accommodated in the first electrode lead-out hole 221, or only a portion of it can be accommodated in the first electrode lead-out hole 221.

[0169] As an example, the shape of the second terminal portion 312 is adapted to the shape of the first electrode lead-out hole 221. For example, if the first electrode lead-out hole 221 is a circular hole, the second terminal portion 312 can be a cylindrical structure; for example, if the first electrode lead-out hole 221 is a square hole, the second terminal portion 312 can be a prism structure; for example, if the first electrode lead-out hole 221 is a racetrack-shaped hole, the second terminal portion 312 can be racetrack-shaped.

[0170] The number of second terminal portions 312 may correspond to the number of first electrode lead-out holes 221. In some examples, there are multiple second terminal portions 312 and multiple first electrode lead-out holes 221, with each of the multiple first electrode lead-out holes 221 corresponding to a single second terminal portion 312; alternatively, there may be only one second terminal portion 312 and one first electrode lead-out hole 221.

[0171] The second terminal portion 312 and the third terminal portion 313 are provided in a one-to-one correspondence. Optionally, there is only one second terminal portion 312 and one third terminal portion 313.

[0172] The third terminal 313 can be connected to the first connecting plate 32 by bonding, welding, riveting or other means.

[0173] During the cycling process of battery cell 6, current can be conducted between the first electrode terminal 31 and the first connecting plate 32 through the connection between the third terminal portion 313 and the first connecting plate 32, or through the contact surface between the second terminal portion 312 and the first connecting plate 32. In this embodiment, by providing the second terminal portion 312 and the third terminal portion 313 protruding from the second terminal portion 312, the contact area between the first electrode terminal 31 and the first connecting plate 32 can be increased, the resistance of the first terminal assembly 30 can be reduced, the temperature rise during overcurrent can be decreased, the overcurrent capacity can be improved, the cycle performance and cycle life of battery cell 6 can be improved, and the risk of thermal runaway of battery cell 6 during fast charging can be reduced.

[0174] In some embodiments, the projection of the third terminal portion 313 is located within the projection of the second terminal portion 312 in the thickness direction Z of the wall portion 20a. The projected area of ​​the third terminal portion 313 in the thickness direction Z is smaller than the projected area of ​​the second terminal portion 312 in the thickness direction Z.

[0175] In some embodiments, when assembling the end cap 22 and the first terminal assembly 30, the third terminal portion 313 can be passed through the first electrode lead-out hole 221 from one side of the end cap 22, and then the first connecting plate 32 can be connected to the third terminal portion 313 from the other side of the end cap 22.

[0176] In some embodiments, the surface of the second terminal portion 312 that abuts against the first connecting plate 32 surrounds the third terminal portion 313.

[0177] As an example, the second terminal portion 312 protrudes from the outer peripheral surface of the third terminal portion 313; viewed along the thickness direction Z, the portion of the second terminal portion 312 that protrudes from the outer peripheral surface of the third terminal portion 313 surrounds the third terminal portion 313.

[0178] The embodiments of this application can increase the contact area between the second terminal portion 312 and the first connecting plate 32, improve the current carrying capacity, and thereby reduce the temperature rise of the first terminal assembly 30 during the cycling process of the battery cell 6.

[0179] In some embodiments, the second terminal portion 312 is cylindrical, and the surface of the second terminal portion 312 that abuts against the first connecting plate 32 is an annular surface.

[0180] In other embodiments, the second terminal portion 312 is racetrack shaped, that is, the cross section of the second terminal portion 312 perpendicular to the thickness direction Z is racetrack shaped; optionally, the surface of the second terminal portion 312 that abuts against the first connecting plate 32 is annular.

[0181] In some embodiments, the first connecting plate 32 is provided with a first through hole 32a; at least a portion of the third terminal portion 313 is accommodated in the first through hole 32a and connected to the first connecting plate 32.

[0182] The third terminal 313 can be connected to the first connecting plate 32 by riveting or welding.

[0183] By providing the first through hole 32a, it is easy to connect the third terminal 313 to the first connecting plate 32 from the side of the first connecting plate 32 facing away from the second terminal 312.

[0184] In some alternative embodiments, the first connecting plate 32 may not have the first through hole 32a.

[0185] In some examples, the first connecting plate 32 has a first groove on the side facing the second terminal portion 312, and the third terminal portion 313 can be accommodated in the first groove. For example, conductive adhesive can be filled into the first groove to achieve the connection between the third terminal portion 313 and the first connecting plate 32; for example, a laser can be irradiated on the side of the bottom wall of the first groove facing away from the third terminal portion 313 to laser weld the bottom wall of the first groove to the third terminal portion 313.

[0186] In other examples, the first connecting plate 32 and the third terminal portion 313 are arranged side by side, and their junction can be connected by welding.

[0187] In some embodiments, at least a portion of the third terminal portion 313 is accommodated in the first through hole 32a, and the third terminal portion 313 is riveted to the first connecting plate 32. The riveting method is easy to implement and can provide high connection strength.

[0188] In some embodiments, the first through hole 32a is a stepped hole. The larger end of the stepped hole is located on the side of the smaller end of the stepped hole away from the second terminal portion 312.

[0189] For example, after the third terminal portion 313 is inserted into the first through hole 32a, the end of the third terminal portion 313 away from the second terminal portion 312 is squeezed to form a flange structure, thereby realizing the riveting of the first electrode terminal 31 to the first connecting plate 32.

[0190] In some embodiments, the third terminal portion 313 does not extend beyond the surface of the first connecting plate 32 away from the wall portion 20a in the direction from the second terminal portion 312 to the third terminal portion 313.

[0191] As an example, the direction in which the second terminal portion 312 points to the third terminal portion 313 is parallel to the thickness direction Z of the wall portion 20a.

[0192] The embodiments of this application can save the space occupied by the third terminal portion 313, reduce the risk of interference between the third terminal portion 313 and other components, and improve the reliability of the battery cell 6.

[0193] In some embodiments, the area of ​​the minimum cross-section of the second terminal portion 312 perpendicular to the thickness direction Z of the wall portion 20a is S1, and the area of ​​the minimum cross-section of the third terminal portion 313 perpendicular to the thickness direction Z is S2. 1.5≤S1 / S2≤25.

[0194] As an example, S1 / S2 can be 1.5, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 21, 22, 23, 24 or 25.

[0195] In this embodiment, setting S1 / S2 to greater than or equal to 1.5 increases the contact area between the second terminal portion 312 and the first connecting plate 32, improves the current-carrying capacity between the second terminal portion 312 and the first connecting plate 32, and reduces the temperature rise of the first terminal assembly 30 during the cycling process of the battery cell 6. The third terminal portion 313 can constrain the first connecting plate 32 to improve the stability of the contact between the second terminal portion 312 and the first connecting plate 32. Setting S1 / S2 to less than or equal to 25 reduces the maximum size difference between the second terminal portion 312 and the third terminal portion 313, allowing the first connecting plate 32 to maintain stable contact with the second terminal portion 312 under the constraint of the third terminal portion 313, thereby improving the current-carrying capacity and reducing the risk of connection failure between the first electrode terminal 31 and the first connecting plate 32.

[0196] In some embodiments, 2≤S1 / S2≤10 can further enhance the overcurrent capacity between the first electrode terminal 31 and the first connecting plate 32, and reduce the temperature rise of the first terminal assembly 30 during the cycling process of the battery cell 6.

[0197] In some embodiments, the first electrode terminal 31 is riveted to the first connecting plate 32. Setting S1 / S2 in the range of 1.5-25 can balance the riveting strength and the current carrying capacity.

[0198] In some embodiments, the surface of the second terminal portion 312 that abuts against the first connecting plate 32 is an annular shape, and the outer diameter of the surface of the second terminal portion 312 that abuts against the first connecting plate 32 is D1; ​​the diameter of the end of the third terminal portion 313 that is connected to the second terminal portion 312 is D2; D1 is greater than D2.

[0199] In some embodiments, 1.2 ≤ D1 / D2 ≤ 5. Alternatively, 2 ≤ D1 / D2 ≤ 4.

[0200] In some embodiments, the first connecting plate 32 is located on the side of the wall portion 20a away from the electrode assembly 10. The first connecting plate 32 is provided with a first through hole 32a, and at least a portion of the third terminal portion 313 is accommodated in the first through hole 32a and connected to the first connecting plate 32.

[0201] By placing the first connecting plate 32 on the outside of the wall portion 20a, the third terminal portion 313 and the first connecting plate 32 can be connected from the outside of the wall portion 20a. During the connection process, impurities sputtered to the inside of the wall portion 20a are reduced, the risk of impurities falling into the electrode assembly 10 is reduced, and the reliability of the battery cell 6 is improved.

[0202] In some embodiments, the first connecting plate 32 and the third terminal portion 313 constitute a lead-out portion 33, and the area of ​​the lead-out portion 33 projected along the thickness direction Z of the wall portion 20a is S3. The area of ​​the wall portion 20a projected along the thickness direction Z is S4. 0.03≤S3 / S4≤0.5.

[0203] As an example, S3 / S4 can be 0.03, 0.05, 0.08, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45 or 0.5.

[0204] As an example, S4 can be the area enclosed by the outer periphery of the projection of the wall portion 20a along the thickness direction Z. For example, if the wall portion 20a is rectangular, S4 can be equal to the length of the wall portion 20a multiplied by the width of the wall portion 20a. As an example, S3 can be the area enclosed by the outer periphery of the projection of the first connecting plate 32 along the thickness direction Z.

[0205] Setting S3 / S4 to greater than or equal to 0.03 allows the lead-out portion 33 to have a larger area, thereby improving its current-carrying capacity and heat dissipation area, reducing the temperature rise of the first terminal assembly 30 during the cycling process of the battery cell 6, and improving the cycle performance of the battery cell 6. Setting S3 / S4 to less than or equal to 0.5 allows for the provision of installation space for other components and reduces the impact of increasing the lead-out portion 33 on the energy density of the battery cell 6.

[0206] In some embodiments, 0.05 ≤ S3 / S4 ≤ 0.2, in order to balance the current carrying capacity of the lead-out portion 33 and the space occupied by the lead-out portion 33.

[0207] In some embodiments, the area of ​​the minimum cross-section of the second terminal portion 312 perpendicular to the thickness direction Z of the wall portion 20a is S1. The first connecting plate 32 and the third terminal portion 313 constitute the lead-out portion 33, and the area of ​​the minimum cross-section of the lead-out portion 33 perpendicular to the thickness direction Z of the wall portion 20a is S5. 0.2≤S1 / S5≤0.8.

[0208] As an example, S1 / S5 is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8.

[0209] Setting S1 / S5 to be greater than or equal to 0.2 reduces the difference between the current-carrying area of ​​the second terminal portion 312 and the current-carrying area of ​​the lead-out portion 33, thereby improving the current-carrying capacity. Setting S1 / S5 to be less than or equal to 0.8 allows for a larger overlap area between the lead-out portion 33 and the wall portion 20a, increasing the connection strength between the first terminal assembly 30 and the wall portion 20a, reducing the risk of deformation and failure of the lead-out portion 33 when the battery cell 6 is subjected to impact, and improving the reliability of the battery cell 6.

[0210] In some embodiments, 0.3 ≤ S1 / S5 ≤ 0.7 can further balance the overcurrent capacity and reliability of the battery cell 6.

[0211] In some embodiments, S5 ≤ S3.

[0212] In some embodiments, the area of ​​the minimum cross-section of the first connecting plate 32 in the thickness direction Z perpendicular to the wall portion 20a is greater than the area of ​​the minimum cross-section of the second terminal portion 312 in the thickness direction Z perpendicular to the wall portion 20a.

[0213] In some embodiments, the first tab 12 is directly connected to the first terminal portion 311.

[0214] In some embodiments, the first tab 12 is welded to the first terminal portion 311 to form the tab welding portion W1.

[0215] In some embodiments, the tab welding portion W1 and the second terminal portion 312 at least partially overlap in the thickness direction Z of the wall portion 20a. This embodiment can reduce the conductive path between the tab welding portion W1 and the second terminal portion 312, reduce resistance, lower the temperature rise during overcurrent, and improve overcurrent capability.

[0216] In some embodiments, the projection of the tab welding portion W1 is located within the projection of the second terminal portion 312 in the thickness direction Z of the wall portion 20a.

[0217] In some embodiments, the electrode assembly 10 further includes a second tab 13, the first tab 12 and the second tab 13 having opposite polarities. The battery cell 6 also includes a second terminal assembly 40 disposed on the housing 20, the second terminal assembly 40 being electrically connected to the second tab 13.

[0218] The first terminal assembly 30 and the second terminal assembly 40 can be disposed on the same wall of the housing 20, or they can be disposed on two separate walls of the housing 20.

[0219] In some embodiments, the second terminal assembly 40 and the first electrode terminal 31 are disposed on the wall portion 20a.

[0220] In some embodiments, the wall portion 20a includes a second electrode lead-out hole 222. The second terminal assembly 40 includes a second electrode terminal 41 and a second connecting plate 42. The second electrode terminal 41 includes a fourth terminal portion 421, a fifth terminal portion 422, and a sixth terminal portion 423. The second connecting plate 42 and the fourth terminal portion 421 are located on opposite sides of the wall portion 20a. The fifth terminal portion 422 is located on the side of the fourth terminal portion 421 facing the second connecting plate 42, and at least a portion of the fifth terminal portion 422 is accommodated in the second electrode lead-out hole 222. The surface of the fifth terminal portion 422 away from the fourth terminal portion 421 abuts against the second connecting plate 42. The sixth terminal portion 423 protrudes from the surface of the fifth terminal portion 422 that abuts against the second connecting plate 42 and is connected to the second connecting plate 42.

[0221] The second electrode lead-out hole 222 penetrates the wall portion 20a. For example, the second electrode lead-out hole 222 penetrates the wall portion 20a along the thickness direction Z of the wall portion 20a.

[0222] The second electrode lead-out hole 222 can be one or more.

[0223] The second electrode lead-out hole 222 can be a round hole, a rectangular hole, an elliptical hole, a racetrack-shaped hole, or other shapes.

[0224] The second electrode 13 can be either a positive or negative electrode. The polarity of the second terminal assembly 40 corresponds to the polarity of the second electrode 13.

[0225] The second terminal assembly 40 and the second tab 13 can be directly connected, or they can be indirectly connected through other conductive structures.

[0226] The second terminal assembly 40 can be one or more.

[0227] In some examples, the second connecting plate 42 may be located on the side of the wall portion 20a facing away from the electrode assembly 10, and the fourth terminal portion 421 may be located on the side of the wall portion 20a facing the electrode assembly 10; in other words, the second connecting plate 42 may be located on the outer side of the wall portion 20a, and the fourth terminal portion 421 may be located on the inner side of the wall portion 20a. In other examples, the second connecting plate 42 may be located on the side of the wall portion 20a facing the electrode assembly 10, and the fourth terminal portion 421 may be located on the side of the wall portion 20a facing away from the electrode assembly 10; in other words, the second connecting plate 42 may be located on the inner side of the wall portion 20a, and the fourth terminal portion 421 may be located on the outer side of the wall portion 20a.

[0228] The fifth terminal portion 422 can be entirely accommodated in the second electrode lead-out hole 222, or only a portion of it can be accommodated in the second electrode lead-out hole 222.

[0229] As an example, the shape of the fifth terminal portion 422 is adapted to the shape of the second electrode lead-out hole 222. For example, if the second electrode lead-out hole 222 is a round hole, the fifth terminal portion 422 can be a cylindrical structure; for example, if the second electrode lead-out hole 222 is a square hole, the fifth terminal portion 422 can be a prism structure.

[0230] The number of fifth terminal portions 422 may correspond to the number of second electrode lead-out holes 222. In some examples, there are multiple fifth terminal portions 422 and multiple second electrode lead-out holes 222, with each of the multiple second electrode lead-out holes 222 corresponding to a single fifth terminal portion 422; alternatively, there may be only one fifth terminal portion 422 and one second electrode lead-out hole 222.

[0231] The fifth terminal portion 422 and the sixth terminal portion 423 are provided in a one-to-one correspondence. Optionally, there is only one fifth terminal portion 422 and one sixth terminal portion 423.

[0232] The sixth terminal 423 can be connected to the second connecting plate 42 by bonding, welding, riveting or other means.

[0233] During the cycling process of battery cell 6, current can be conducted between the second electrode terminal 41 and the second connecting plate 42 through the connection between the sixth terminal portion 423 and the second connecting plate 42, or through the contact surface between the fifth terminal portion 422 and the second connecting plate 42. In this embodiment, by providing the fifth terminal portion 422 and the sixth terminal portion 423 protruding from the fifth terminal portion 422, the contact area between the second electrode terminal 41 and the second connecting plate 42 can be increased, the resistance of the second terminal assembly 40 can be reduced, the temperature rise during overcurrent can be decreased, the overcurrent capacity can be improved, the cycle performance and cycle life of battery cell 6 can be improved, and the risk of thermal runaway of battery cell 6 during fast charging can be reduced.

[0234] In some embodiments, both the first connecting plate 32 and the second connecting plate 42 are located on the outside of the wall portion 20a.

[0235] In some embodiments, the ratio of the projected area of ​​the first connecting plate 32 along the thickness direction Z to the projected area of ​​the second connecting plate 42 along the thickness direction Z is 0.8-1.2. The flow area of ​​the first connecting plate 32 is close to that of the second connecting plate 42.

[0236] In some embodiments, the first electrode 12 is a positive electrode and the second electrode 13 is a negative electrode.

[0237] Figure 9 is a structural schematic diagram of a battery cell provided in some other embodiments of this application; Figure 10 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of this application; Figure 11 is an exploded schematic diagram of the first terminal assembly of a battery cell provided in some other embodiments of this application.

[0238] Referring to Figures 9 to 11, in some embodiments, the first connecting plate 32 is located on the side of the wall portion 20a away from the electrode assembly 10. The first connecting plate 32 includes a first plate portion 321 and a second plate portion 322 connected to the first plate portion 321. The base metal of the first plate portion 321 is different from the base metal of the second plate portion 322, and the base metal of the second plate portion 322 is the same as the base metal of the first electrode terminal 31. A third terminal portion 313 is connected to the second plate portion 322.

[0239] The second terminal portion 312 may or may not contact the second plate portion 322.

[0240] When the material of the first electrode terminal 31 is different from that of the busbar component, the first connecting plate 32 can act as a connector to improve the connection strength between the first connecting plate 32 and the busbar component, and between the first connecting plate 32 and the first electrode terminal 31, thereby enhancing the current carrying capacity. The base metal of the third terminal portion 313 is the same as the base metal of the second plate portion 322. By connecting the third terminal portion 313 and the second plate portion 322, the contact resistance between them can be reduced, thereby improving the current carrying capacity.

[0241] In some embodiments, the base metal of the first electrode terminal 31, the base metal of the first tab 12, and the base metal of the second plate portion 322 are all the same. For example, the first tab 12 is made of copper or a copper alloy, the first electrode terminal 31 is made of copper or a copper alloy, and the second plate portion 322 is made of copper or a copper alloy.

[0242] Copper has low resistivity and strong thermal conductivity. Using copper for the first electrode terminal 31 can improve the overcurrent capacity of the first electrode terminal 31, reduce the heat generated by the first electrode terminal 31 during overcurrent, improve the efficiency of heat dissipation, and reduce the internal temperature of the battery cell 6.

[0243] In some embodiments, the base metal of the first plate portion 321 is the same as the base metal of the busbar component. For example, the first plate portion 321 is made of aluminum or an aluminum alloy, and the busbar component is made of aluminum or an aluminum alloy.

[0244] In some embodiments, the first connecting plate 32 is a copper-aluminum composite plate.

[0245] In some embodiments, the first plate portion 321 has a second groove 32b on the side facing away from the wall portion 20a, and the second plate portion 322 can be accommodated in the second groove 32b.

[0246] In some embodiments, the first through hole 32a extends through the second plate portion 322 and the first plate portion 321.

[0247] In some embodiments, at least one end of the second terminal portion 312 protrudes from the second plate portion 322 in the first direction X; the portion of the second terminal portion 312 protruding from the second plate portion 322 in the first direction X abuts against the first plate portion 321, and the first direction X is perpendicular to the thickness direction Z of the wall portion 20a.

[0248] As an example, the first direction X can be a straight line direction perpendicular to the thickness direction Z. For example, the first direction X can be the length direction of the wall portion 20a or the width direction of the wall portion 20a.

[0249] The second terminal portion 312 protrudes from the second plate portion 322 in the first direction X, which can increase the current-carrying area of ​​the second terminal portion 312 and the contact area between the second terminal portion 312 and the first plate portion 321, thereby reducing the resistance of the first terminal assembly 30, reducing the temperature rise generated during current flow, improving the current-carrying capacity, and improving the cycle performance and cycle life of the battery cell 6.

[0250] In some embodiments, the first direction X may be parallel to the length direction of the wall portion 20a.

[0251] In some embodiments, the second groove 32b extends through the first plate portion 321 along the second direction Y; the second direction Y, the first direction X, and the thickness direction Z are perpendicular to each other.

[0252] The two ends of the second plate portion 322 along the second direction Y are flush with the two ends of the first plate portion 321 along the second direction Y.

[0253] In some embodiments, at least a portion of the first plate portion 321 is disposed between the second terminal portion 312 and the second plate portion 322 in the thickness direction Z, and abuts against both the second terminal portion 312 and the second plate portion 322.

[0254] The embodiments of this application can increase the contact area between the first plate portion 321 and the second plate portion 322, as well as the contact area between the first plate portion 321 and the second terminal portion 312, thereby reducing the resistance of the first terminal assembly 30, reducing the temperature rise during overcurrent, improving the overcurrent capacity, and improving the cycle performance and cycle life of the battery cell 6.

[0255] In some embodiments, the second plate portion 322 surrounds the third terminal portion 313. The outer peripheral surface of the third terminal portion 313 is in contact with the second plate portion 322.

[0256] In some embodiments, the third terminal portion 313 is riveted to the first plate portion 321.

[0257] In some embodiments, the first terminal assembly 30 is a negative terminal assembly and the second terminal assembly 40 is a positive terminal assembly.

[0258] In some embodiments, the material of the second connecting plate 42 is the same as that of the first connecting plate 32.

[0259] Figure 12 is an exploded view of the first terminal assembly of a battery cell provided in some other embodiments of this application.

[0260] Referring to FIG12, in some embodiments, the maximum dimension of the second terminal portion 312 along the first direction X is greater than the maximum dimension of the second terminal portion 312 along the second direction Y, and the first direction X, the second direction Y, and the thickness direction Z are perpendicular to each other. Embodiments of this application can increase the dimension of the second terminal portion 312 in the first direction X to improve the current-carrying capacity of the second terminal portion 312.

[0261] In some embodiments, the first direction X is parallel to the length direction of the wall portion 20a, and the second direction Y is parallel to the width direction of the wall portion 20a. This embodiment can effectively utilize the space along the length direction of the wall portion 20a to increase the size of the second terminal portion 312 along the first direction X, thereby improving the current-carrying capacity of the second terminal portion 312.

[0262] In some embodiments, the cross-section of the second terminal portion 312 perpendicular to the thickness direction Z is elliptical, rectangular, or racetrack-shaped. Optionally, the cross-section of the second terminal portion 312 perpendicular to the thickness direction Z is racetrack-shaped.

[0263] Figure 13 is a simplified schematic diagram of a battery device provided in some embodiments of this application; Figure 14 is a partial cross-sectional schematic diagram of a battery device provided in some embodiments of this application.

[0264] Referring to Figures 13 and 14, this application embodiment also provides a battery device 2, which includes a plurality of battery cells 6 provided in any of the foregoing embodiments.

[0265] In some embodiments, the battery device 2 further includes a busbar 7. Exemplarily, there are multiple busbars 7, which connect multiple battery cells 6 in series, parallel, or mixed connections.

[0266] Multiple busbar components 7 can adopt the same structure or different structures.

[0267] The busbar component 7 can be a single-layer structure or a multi-layer structure.

[0268] In some embodiments, the busbar 7 is connected to the first terminal assembly 30 of one battery cell 6 and the second terminal assembly 40 of another battery cell 6 to connect the two battery cells 6 in series. Alternatively, the busbar 7 is connected to the first terminal assemblies 30 of both battery cells 6 to connect the two battery cells 6 in parallel.

[0269] In some embodiments, the bus component 7 is welded to the first terminal assembly 30 to form a welded portion W2.

[0270] There can be one or more welded parts W2. The welded parts W2 can be straight, curved, ring-shaped, or other shapes.

[0271] In some examples, the first terminal portion 311 is located outside the wall portion 20a, and the bus component 7 is welded to the first terminal portion 311 to form a weld portion W2. In other examples, the first connecting plate 32 is located outside the wall portion 20a, and the bus component 7 is welded to the first connecting plate 32 to form a weld portion W2.

[0272] By providing the welding part W2, the connection strength between the bus component 7 and the first terminal assembly 30 can be improved, the resistance between the bus component 7 and the first terminal assembly 30 can be reduced, the temperature rise of the first terminal assembly 30 and the bus component 7 during overcurrent can be reduced, and the cycle performance can be improved.

[0273] In some embodiments, the first connecting plate 32 is located on the side of the wall 20a away from the electrode assembly 10. The busbar component 7 is welded to the first connecting plate 32 and forms at least a portion of the welded portion W2.

[0274] In some examples, the welded portion W2 may be formed entirely of the busbar 7 and the first connecting plate 32. For example, during welding, a portion of the busbar 7 and a portion of the first connecting plate 32 melt and form a molten pool, which solidifies to form the welded portion W2. In other examples, a portion of the welded portion W2 is formed by the busbar 7 and the first connecting plate 32.

[0275] In some embodiments, the busbar component 7 is laser welded to the first connecting plate 32.

[0276] In some embodiments, the projection of the weld portion W2 in the thickness direction Z of the wall portion 20a at least partially overlaps with the projection of the second terminal portion 312.

[0277] The embodiments of this application can shorten the conductive path between the second terminal portion 312 and the welding portion W2, reduce resistance, reduce the temperature rise of the first terminal assembly 30 during overcurrent, improve the cycle performance of the battery cell 6, and reduce the risk of thermal runaway of the battery cell 6.

[0278] In some embodiments, the portion of the welding portion W2 that overlaps with the second terminal portion 312 along the thickness direction Z is disposed along the outer periphery of the third terminal portion 313. Exemplarily, the portion of the welding portion W2 that overlaps with the second terminal portion 312 along the thickness direction Z can be disposed continuously or intermittently.

[0279] In some embodiments, the area of ​​the projection of the welded portion W2 along the thickness direction Z is S6. The overlapping area between the projection of the welded portion W2 along the thickness direction Z and the projection of the second terminal portion 312 along the thickness direction Z is S7. 0.05≤S7 / S6≤1.

[0280] As an example, S7 / S6 can be 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.0.

[0281] Setting S6 / S7 to greater than or equal to 0.05 can shorten the conductive path between the second terminal portion 312 and the welding portion W2, reduce resistance, reduce the temperature rise of the first terminal assembly 30 during overcurrent, improve the cycle performance of the battery cell 6, and reduce the risk of thermal runaway of the battery cell 6.

[0282] In some embodiments, the maximum dimension of the second terminal portion 312 along the first direction X is greater than the maximum dimension of the second terminal portion 312 along the second direction Y, and the first direction X, the second direction Y, and the thickness direction Z are perpendicular to each other. The welding portion W2 includes a first welding portion W21 and a second welding portion W22 spaced apart along the first direction X. In the thickness direction Z, the first welding portion W21 overlaps with one end of the second terminal portion 312 along the first direction X, and the second welding portion W22 overlaps with the other end of the second terminal portion 312 along the first direction X. The second terminal portion 312 has a larger dimension in the first direction X, which increases the current-carrying area of ​​the second terminal portion 312 and reduces the conductive paths between the second terminal portion 312 and the first welding portion W21, as well as between the second terminal portion 312 and the second welding portion W22, thereby improving the current-carrying capacity.

[0283] In some embodiments, the first welding portion W21 is linear and extends along the second direction Y, and the second welding portion W22 is linear and extends along the second direction Y.

[0284] Figure 15 is a partial cross-sectional schematic diagram of a battery device provided in some other embodiments of this application.

[0285] Referring to FIG15, in some embodiments, the projection of the weld portion W2 is located within the projection of the second terminal portion 312 in the thickness direction Z of the wall portion 20a.

[0286] For example, S7 / S6 = 1.

[0287] The embodiments of this application can further shorten the conductive path between the second terminal portion 312 and the welding portion W2, reduce resistance, reduce the temperature rise of the first terminal assembly 30 during overcurrent, improve the cycle performance of the battery cell 6, and reduce the risk of thermal runaway of the battery cell 6. When welding the first connecting plate 32 and the bus component 7, even if the first connecting plate 32 is welded through, the second terminal portion 312 can also stop the molten pool, reducing the risk of other components of the battery cell 6 being melted through and improving the reliability of the battery cell 6.

[0288] In some embodiments, a portion of the welding portion W2 is formed on the second terminal portion 312.

[0289] For example, during welding, a portion of the busbar 7, a portion of the first connecting plate 32, and a portion of the second terminal portion 312 melt and form a molten pool, and the second terminal portion 312 is formed after the molten pool solidifies.

[0290] Part of the current in the second terminal portion 312 can be conducted to the busbar 7 through the welding portion W2, which can further reduce resistance, reduce the temperature rise of the first terminal assembly 30 during overcurrent, improve the cycle performance of the battery cell 6, and reduce the risk of thermal runaway of the battery cell 6. The welding portion W2 can also improve the connection strength between the first electrode terminal 31 and the first connecting plate 32, enhance the stability of the contact between the second terminal portion 312 and the first connecting plate 32, reduce contact resistance, and improve overcurrent capacity.

[0291] In some embodiments, the welded portion W2 and the tab welded portion W1 at least partially overlap in the thickness direction Z of the wall portion 20a, which can shorten the conductive path between the first tab 12 and the busbar 7, reduce resistance, reduce the temperature rise of the first terminal assembly 30 during overcurrent, and improve the cycle performance of the battery cell 6.

[0292] In some embodiments, the welded portion W2 is annular.

[0293] In some embodiments, the portion of the welded portion W2 that overlaps with the second terminal portion 312 along the thickness direction Z surrounds the third terminal portion 313. The portion of the welded portion W2 that overlaps with the second terminal portion 312 along the thickness direction Z is continuously provided along the outer periphery of the third terminal portion 313, which can reduce the conductive path, increase the current flow area, and improve the consistency of current flow.

[0294] Figure 16 is a partial cross-sectional schematic diagram of a battery device provided in some other embodiments of this application.

[0295] Referring to FIG16, in some embodiments, the first connecting plate 32 includes a first portion 323 and a second portion 324 connected to each other. The first portion 323 surrounds and contacts the third terminal portion 313, and the thickness of the second portion 324 is less than the thickness of the first portion 323. The bus member 7 abuts against the surface of the second portion 324 away from the second terminal portion 312, and the bus member 7, the second portion 324, and the second terminal portion 312 are welded to form a welded portion W2.

[0296] Compared to the first portion 323, the second portion 324 has a smaller thickness. Connecting the second portion 324 to the busbar component 7 reduces welding power, decreases heat generation during welding, reduces the risk of failure of the insulating component 60 near the first terminal assembly 30, and improves the reliability of the battery cell 6. Compared to the second portion 324, the first portion 323 is closer to the third terminal portion 313 and has a larger thickness. This increases the connection strength between the third terminal portion 313 and the first connecting plate 32, reduces deformation of the first connecting plate 32 when connected to the third terminal portion 313, and improves reliability.

[0297] In some embodiments, the first connecting plate 32 further includes a third portion 325, the thickness of which is less than the thickness of the first portion 323, and the first portion 323 surrounds the third portion 325. In the thickness direction Z of the wall portion 20a, the third portion 325 is located between the flange structure of the third terminal portion 313 and the second terminal portion 312.

[0298] In some embodiments, the first connecting plate 32 has a recess 326 on the side away from the wall portion 20a, and the second portion 324 is the bottom wall of the recess 326.

[0299] In some embodiments, the first connecting plate 32 includes a first plate portion and a second plate portion; the first plate portion includes a second part.

[0300] 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.

[0301] Referring to Figures 3 to 8, an embodiment of this application provides a battery cell 6, which includes a housing 20, an electrode assembly 10, a first terminal assembly 30, and a second terminal assembly 40.

[0302] The housing 20 includes a housing 21 and an end cap 22. The housing 21 has an opening, and the end cap 22 is connected to the housing 21 and covers the opening. The end cap 22 is provided with a first electrode lead-out hole 221 and a second electrode lead-out hole 222.

[0303] The electrode assembly 10 includes an electrode body 11, a first electrode tab 12, and a second electrode tab 13, which extend from the electrode body 11. The first electrode tab 12 and the second electrode tab 13 have opposite polarities.

[0304] The first terminal assembly 30 and the second terminal assembly 40 are insulatedly mounted on the end cap 22. The first terminal assembly 30 is electrically connected to the first tab 12, and the second terminal assembly 40 is electrically connected to the second tab 13.

[0305] The first terminal assembly 30 includes a first electrode terminal 31 and a first connecting plate 32. The first electrode terminal 31 includes a first terminal portion 311, a second terminal portion 312, and a third terminal portion 313. The first connecting plate 32 is located outside the end cap 22, and the first terminal portion 311 is located inside the end cap 22. The second terminal portion 312 is located on the side of the first terminal portion 311 facing the first connecting plate 32, and at least a portion of the second terminal portion 312 is accommodated in the first electrode lead-out hole 221. The surface of the second terminal portion 312 away from the first terminal portion 311 abuts against the first connecting plate 32.

[0306] The first connecting plate 32 is provided with a first through hole 32a, and the third terminal portion 313 protrudes from the surface of the second terminal portion 312 that abuts against the first connecting plate 32. At least a portion of the third terminal portion 313 is accommodated in the first through hole 32a and connected to the first connecting plate 32.

[0307] The minimum diameter of the second terminal portion 312 is greater than the maximum diameter of the third terminal portion 313.

[0308] The second terminal assembly 40 includes a second electrode terminal 41 and a second connecting plate 42. The second electrode terminal 41 includes a fourth terminal portion 421, a fifth terminal portion 422, and a sixth terminal portion 423. The second connecting plate 42 is located outside the end cap 22, and the fourth terminal portion 421 is located inside the end cap 22. The fifth terminal portion 422 is located on the side of the fourth terminal portion 421 facing the second connecting plate 42, and at least a portion of the fifth terminal portion 422 is accommodated in the second electrode lead-out hole 222. The surface of the fifth terminal portion 422 away from the fourth terminal portion 421 abuts against the second connecting plate 42.

[0309] The second connecting plate 42 is provided with a second through hole 42a, and a sixth terminal portion 423 protrudes from the surface of the fifth terminal portion 422 that abuts against the second connecting plate 42. At least a portion of the sixth terminal portion 423 is accommodated in the second through hole 42a and connected to the second connecting plate 42.

[0310] The minimum diameter of the fifth terminal portion 422 is greater than the maximum diameter of the sixth terminal portion 423.

[0311] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0312] 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 they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for 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 single battery cell, comprising: The outer casing includes a wall portion, wherein the wall portion is provided with a first electrode lead-out hole; An electrode assembly, housed within the housing, the electrode assembly including a first tab; A first terminal assembly is electrically connected to the first electrode tab. The first terminal assembly includes a first electrode terminal and a first connecting plate. The first electrode terminal includes a first terminal portion, a second terminal portion and a third terminal portion. The first connecting plate and the first terminal portion are respectively located on both sides of the wall portion along the thickness direction of the wall portion. The second terminal portion is located on the side of the first terminal portion facing the first connecting plate, and at least a portion of the second terminal portion is accommodated in the first electrode lead-out hole. The second terminal portion has its surface away from the first terminal portion abutting against the first connecting plate, and the third terminal portion protrudes from the surface of the second terminal portion that abuts against the first connecting plate and is connected to the first connecting plate.

2. The battery cell according to claim 1, wherein, The surface of the second terminal portion that abuts against the first connecting plate surrounds the third terminal portion.

3. The battery cell according to claim 1 or 2, wherein, The first connecting plate is provided with a first through hole; at least a portion of the third terminal portion is accommodated in the first through hole and connected to the first connecting plate.

4. The battery cell according to claim 3, wherein, The third terminal is riveted to the first connecting plate.

5. The battery cell according to claim 3 or 4, wherein, Along the direction from the second terminal portion to the third terminal portion, the third terminal portion does not extend beyond the surface of the first connecting plate away from the wall portion.

6. The battery cell according to any one of claims 2-5, wherein, The area of ​​the smallest cross-section of the second terminal portion perpendicular to the thickness direction is S1, and the area of ​​the smallest cross-section of the third terminal portion perpendicular to the thickness direction is S2. 1.5≤S1 / S2≤25; optionally, 2≤S1 / S2≤10.

7. The battery cell according to any one of claims 1-6, wherein, The first connecting plate is located on the side of the wall away from the electrode assembly; The first connecting plate is provided with a first through hole, and at least a portion of the third terminal portion is accommodated in the first through hole and connected to the first connecting plate.

8. The battery cell according to claim 7, wherein, The first connecting plate and the third terminal portion constitute a lead-out portion, and the area of ​​the lead-out portion projected along the thickness direction is S3; The area of ​​the projection of the wall portion along the thickness direction is S4; 0.03≤S3 / S4≤0.5; optionally, 0.05≤S3 / S4≤0.

2.

9. The battery cell according to claim 7 or 8, wherein, The area of ​​the smallest cross-section of the second terminal portion perpendicular to the thickness direction is S1; The first connecting plate and the third terminal portion constitute a lead-out portion, and the area of ​​the minimum cross-section of the lead-out portion perpendicular to the thickness direction is S5; 0.2≤S1 / S5≤0.8; optionally, 0.3≤S1 / S5≤0.

7.

10. The battery cell according to any one of claims 1-9, wherein, The electrode assembly further includes a second electrode tab, wherein the polarity of the first electrode tab is opposite to that of the second electrode tab; The battery cell further includes a second terminal assembly disposed on the wall portion, the second terminal assembly being electrically connected to the second electrode tab; The wall portion includes a second electrode lead-out hole; The second terminal assembly includes a second electrode terminal and a second connecting plate. The second electrode terminal includes a fourth terminal portion, a fifth terminal portion, and a sixth terminal portion. The second connecting plate and the fourth terminal portion are respectively located on both sides of the wall portion. The fifth terminal portion is located on the side of the fourth terminal portion facing the second connecting plate, and at least a portion of the fifth terminal portion is accommodated in the second electrode lead-out hole. The surface of the fifth terminal portion away from the fourth terminal portion abuts against the second connecting plate. The sixth terminal portion protrudes from the surface of the fifth terminal portion that abuts against the second connecting plate and is connected to the second connecting plate.

11. The battery cell according to any one of claims 1-10, wherein, The first connecting plate is located on the side of the wall away from the electrode assembly; The first connecting plate includes a first plate portion and a second plate portion connected to the first plate portion. The base metal of the first plate portion is different from the base metal of the second plate portion, and the base metal of the second plate portion is the same as the base metal of the first electrode terminal. The third terminal portion is connected to the second plate portion; In the first direction, at least one end of the second terminal portion protrudes from the second plate portion; The portion of the second terminal portion that protrudes from the second plate portion in the first direction abuts against the first plate portion, and the first direction is perpendicular to the thickness direction.

12. The battery cell according to claim 11, wherein, In the thickness direction, at least a portion of the first plate portion is disposed between the second terminal portion and the second plate portion, and abuts against both the second terminal portion and the second plate portion.

13. The battery cell according to any one of claims 1-12, wherein, The first electrode tab is welded to the first terminal portion and forms an electrode tab welding portion; In the thickness direction, the electrode welding portion at least partially overlaps with the second terminal portion.

14. The battery cell according to any one of claims 1-13, wherein, The maximum dimension of the second terminal portion along the first direction is greater than the maximum dimension of the second terminal portion along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other.

15. The battery cell according to claim 14, wherein, The first direction is parallel to the length direction of the wall portion, and the second direction is parallel to the width direction of the wall portion.

16. The battery cell according to claim 14 or 15, wherein, The cross-section of the second terminal portion perpendicular to the thickness direction is elliptical, rectangular, or racetrack-shaped.

17. A battery device comprising a plurality of battery cells according to any one of claims 1-16.

18. The battery device of claim 17, further comprising a busbar component, the busbar component being welded to the first terminal assembly to form a welded portion.

19. The battery device according to claim 18, wherein, The first connecting plate is located on the side of the wall away from the electrode assembly; The busbar component is welded to the first connecting plate and forms at least a portion of the welded portion.

20. The battery device according to claim 19, wherein, In the thickness direction, the projection of the welded portion at least partially overlaps with the projection of the second terminal portion.

21. The battery device according to claim 20, wherein, The area of ​​the welded portion projected along the thickness direction is S6; The overlapping area between the projection of the welded portion along the thickness direction and the projection of the second terminal portion along the thickness direction is S7. 0.05≤S7 / S6≤1; optionally, 0.4≤S7 / S6≤1.

22. The battery device according to claim 20 or 21, wherein, In the thickness direction, the projection of the welded portion is located within the projection of the second terminal portion.

23. The battery device according to any one of claims 20-22, wherein, The portion of the welded part that overlaps with the second terminal part along the thickness direction surrounds the third terminal part.

24. The battery device according to any one of claims 20-23, wherein, The maximum dimension of the second terminal portion along the first direction is greater than the maximum dimension of the second terminal portion along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other; The welding portion includes a first welding portion and a second welding portion spaced apart along the first direction. In the thickness direction, the first welding portion overlaps with one end of the second terminal portion along the first direction, and the second welding portion overlaps with the other end of the second terminal portion along the first direction.

25. The battery device according to any one of claims 19-24, wherein, A portion of the welded portion is formed at the second terminal portion.

26. The battery device according to claim 25, wherein, The first connecting plate includes a first part and a second part connected to each other, the first part surrounding and contacting the third terminal portion, and the thickness of the second part being less than the thickness of the first part; The busbar component abuts against the surface of the second portion away from the second terminal portion, and the busbar component, the second portion, and the second terminal portion are welded together to form the welded portion.

27. An electrical appliance comprising a battery device according to any one of claims 17-26, the battery device being used to provide electrical energy.

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