Battery cell, battery device, and electric device

Abstract

Provided are a battery cell, a battery device and an electric device. The battery cell comprises a housing, an electrode assembly and a pressure-relief component. The housing has a first wall provided with a through hole. The pressure-relief component is connected to the first wall to form a connecting portion, and the pressure-relief component comprises a main portion and a limiting portion. The limiting portion is connected to the main portion and surrounds the outer periphery of the main portion. The main portion is disposed opposite the through hole and has a weakened portion. In the direction of thickness of the first wall, the limiting portion abuts against the first wall. In a projection plane perpendicular to the direction of thickness of the first wall, at least part of an orthographic projection of the limiting portion is located outside an orthographic projection of the connecting portion. Thus, the pressure-relief component can be stressed on two sides of the connecting portion in a radial direction of the through hole, thereby enabling balanced stress on the two sides of the connecting portion and reducing the risk of failure of the connecting portion caused by unbalanced stress in the radial direction of the through hole, and thus improving the reliability of the battery cell and extending the service life of the battery cell.

Description

Battery cells, battery packs and electrical devices 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 device. Background Technology

[0002] Batteries are widely used in new energy vehicles, electronic devices, and other fields. As the demand for batteries increases, higher requirements are being placed on their reliability. Summary of the Invention

[0003] This application provides a battery cell, a battery device, and an electrical device, which can improve the reliability of the battery cell.

[0004] In a first aspect, embodiments of this application provide a battery cell, including a housing, an electrode assembly, and a pressure relief component; the housing has a first wall portion with a through hole; the electrode assembly is housed within the housing; the pressure relief component is connected to the first wall portion to form a connecting portion, the pressure relief component includes a main body portion and a limiting portion, the limiting portion being connected to the main body portion and surrounding at least a portion of the outer periphery of the main body portion, the main body portion being disposed opposite to the through hole, the main body portion having a weak portion, the weak portion being configured to be broken to release pressure inside the battery cell; wherein, along the thickness direction of the first wall portion, the limiting portion abuts against the first wall portion, and in a projection plane perpendicular to the thickness direction of the first wall portion, at least a portion of the orthographic projection of the limiting portion is located outside the orthographic projection of the connecting portion.

[0005] In the above technical solution, by abutting the first wall portion along its thickness direction, the limiting portion abuts against the first wall portion, thus limiting the first wall portion and the pressure relief component. This facilitates the installation of the pressure relief component on the first wall portion and improves the load-bearing capacity of the area where the pressure relief component and the first wall portion abut. Since at least a portion of the orthographic projection of the limiting portion is located outside the orthographic projection of the connection formed by the pressure relief component and the first wall portion in the projection plane perpendicular to the thickness direction of the first wall portion, the pressure relief component can be subjected to force on both sides of the connection portion along the radial direction of the through hole. For example, the pressure relief component may be subjected to internal pressure from the battery cell on both sides of the connection portion along the radial direction of the through hole, or it may be subjected to external loads from the battery cell on both sides of the connection portion along the radial direction of the through hole. This balances the forces on both sides of the connection portion, reducing the risk of failure due to unbalanced radial forces in the through hole, thereby improving the reliability of the battery cell and extending its service life.

[0006] In some embodiments of the first aspect of this application, the main body portion is connected to the first wall portion to form the connecting portion.

[0007] In the above technical solution, the connection between the main body and the first wall portion forms a connecting portion, which improves the connection stability between the pressure relief component and the first wall portion. By connecting the main body and the first wall portion to form a connecting portion, the area outside the connecting portion where the orthogonal projection of the limiting portion in the projection plane perpendicular to the thickness direction of the first wall portion is located is larger. This increases the force-bearing area of ​​the pressure relief component on the outside of the connecting portion, thereby reducing the difference in force-bearing area between the inner and outer sides of the connecting portion. This further reduces the force difference between the inner and outer sides of the connecting portion, making the force on both sides of the connecting portion more balanced. This further reduces the risk of failure of the connecting portion due to unbalanced forces on both sides, thereby improving the reliability of the battery cell and extending its service life.

[0008] In some embodiments of the first aspect of this application, the main body includes a first part and a second part, the first part extending at least partially into the through hole, the limiting part and the second part being respectively connected to both ends of the first part, and the weak part being disposed in the second part; the first part and the first wall part are connected to form the connecting part.

[0009] In the above technical solution, by extending the first part of the main body into the through hole, the first part can be positioned and fitted with the through hole, facilitating the connection between the pressure relief component and the first wall. After extending into the through hole, the first part is closer to the first wall, and the connection between the first part and the first wall forms a connecting part, making the connection between the pressure relief component and the first wall easier. The limiting part and the second part are respectively connected to the two ends of the first part, and the weak part is set in the second part. This helps to form a buffer zone between the limiting part and the second part through the first part, thereby reducing the impact of the force on the second part on the connecting part, further reducing the risk of the connecting part failing due to the imbalance of forces on both sides, improving the reliability of the battery cell and extending the service life of the battery cell.

[0010] In some embodiments of the first aspect of this application, the thickness of the first portion is E, and the thickness of the portion of the first wall that abuts against the limiting portion along the thickness direction of the first wall is D, where D / 5≤E≤5D; optionally, 2D / 3≤E≤3D.

[0011] In the above technical solution, since the first part is connected to the first wall, E≥D / 5 ensures that the first part has sufficient thickness to connect with the first wall, which is beneficial for the connection part to have sufficient connection area, improving the connection stability between the first part and the first wall, thereby improving the reliability of the battery cell. When the connection between the first wall and the first part is achieved by welding, E≥D / 5 can reduce the risk of the first part being welded through while ensuring a large molten pool depth, improving the connection stability between the first wall and the first part. By E≤5D, the thickness of the first part is controlled within a reasonable range, reducing the area occupied by the first part in the through hole, reducing the risk that the first part will affect the pressure relief inside the battery cell through the through hole, and improving the reliability of the battery cell. Therefore, by D / 5≤E≤5D, the connection between the pressure relief component and the first wall can be made more stable, and the impact of the first part on the pressure relief of the through hole can also be reduced. Furthermore, by ensuring E ≥ 2D / 3, the connecting portion has a larger connection area, further improving the connection stability between the first part and the first wall, thereby further improving the reliability of the battery cell. By ensuring E ≤ 3D, the thickness of the first part is controlled within a smaller range, further reducing the area occupied by the first part in the through hole, thereby further reducing the risk of the first part affecting the pressure relief inside the battery cell through the through hole, and improving the reliability of the battery cell. Therefore, by ensuring 2D / 3 ≤ E ≤ 3D, the connection between the pressure relief component and the first wall is more stable, and the impact of the first part on the pressure relief of the through hole is further reduced.

[0012] In some embodiments of the first aspect of this application, along the radial direction of the through hole, there is a first distance K between the connecting portion and the surface of the first portion facing away from the hole wall of the through hole, and the thickness of the limiting portion is d, d / 10≤K≤4d; optionally, d / 5≤K≤3d / 2.

[0013] In the above technical solution, by maintaining a first distance K between the connecting part and the surface of the first part away from the hole wall along the radial direction of the through hole, the connecting part does not extend to the surface of the first part away from the hole wall along the radial direction of the through hole, reducing the impact of the connecting part on the strength of the first part. Especially when the first wall and the pressure relief component are welded to form a connecting part, the first distance between the connecting part and the surface of the first part away from the hole wall along the radial direction of the through hole prevents the first part from being welded through, making the connection between the first wall and the pressure relief component more stable, and improving the overall strength of the structure formed by the pressure relief component and the first wall. By having K ≥ d / 10, the first part still has good strength after being connected to the first wall, which is beneficial to improving the pressure relief component's ability to resist external forces. By having K ≤ 4d, the thickness of the first part can be controlled within a reasonable range, reducing the area occupied by the first part in the through hole, reducing the risk of the first part affecting the pressure relief inside the battery cell from the through hole, and improving the reliability of the battery cell. Therefore, d / 10 ≤ K ≤ 4d ensures that the first part maintains good strength after connecting to the first wall, while also reducing the area occupied by the first part in the through hole. This reduces the risk of the first part affecting the internal pressure release of the battery cell through the through hole, thus improving the reliability of the battery cell. Furthermore, by setting d / 5 ≤ K ≤ 3d / 2, the first part maintains even better strength after connecting to the first wall, while further reducing the area occupied by the first part in the through hole. This further reduces the risk of the first part affecting the internal pressure release of the battery cell through the through hole, further improving the reliability of the battery cell.

[0014] In some embodiments of the first aspect of this application, the connecting portion extends from the surface of the first wall portion away from the limiting portion toward the limiting portion along the thickness direction of the first wall portion.

[0015] In the above technical solution, by extending the connecting part from the surface of the first wall away from the limiting part toward the limiting part, the first wall and the pressure relief component can be connected from the side of the first wall away from the limiting part, making the connection more convenient.

[0016] In some embodiments of the first aspect of this application, there is a second distance H between the connecting portion and the surface of the limiting portion away from the first wall portion, and the thickness of the limiting portion is d, where d / 10≤H≤2d; optionally, d / 5≤H≤d.

[0017] In the above technical solution, by maintaining a second distance H between the connecting portion and the surface of the limiting portion away from the first wall, the connecting portion does not extend to the surface of the limiting portion away from the first wall, reducing the impact of the connecting portion on the strength of the limiting portion. Especially when the first wall and the pressure relief component are welded together to form a connecting portion, the second distance H between the connecting portion and the surface of the limiting portion away from the first wall prevents the limiting portion from being welded through, resulting in a more stable connection between the first wall and the pressure relief component, and better overall strength of the structure formed by the pressure relief component and the first wall. By ensuring H ≥ d / 10, the limiting portion maintains good strength after the pressure relief component is connected to the first wall, which helps improve the pressure relief component's ability to resist external forces. By ensuring H ≤ 2d, the distance between the surface of the limiting portion away from the first wall and the connecting portion is avoided from being too large, which would result in a smaller connecting portion size and consequently lower connection stability between the pressure relief component and the first wall, thus improving the reliability of the battery cell. Therefore, d / 10 ≤ H ≤ 2d ensures that the limiting part maintains good strength after the pressure relief component connects to the first wall, while also providing sufficient connection area for the connecting part, improving the connection stability between the first wall and the pressure relief component, and thus enhancing the reliability of the battery cell. H ≥ d / 5 ensures that the limiting part maintains even better strength after the pressure relief component connects to the first wall, further improving the pressure relief component's resistance to external forces. H ≤ d prevents the distance between the limiting part and the connecting part from being too large, which would result in a smaller connecting part and lower connection stability between the pressure relief component and the first wall, thus improving the reliability of the battery cell. Therefore, d / 5 ≤ H ≤ d ensures that the limiting part maintains better strength after the pressure relief component connects to the first wall, while also providing sufficient connection area for the connecting part, improving the connection stability between the first wall and the pressure relief component, and thus enhancing the reliability of the battery cell.

[0018] In some embodiments of the first aspect of this application, the main body portion is at least partially disposed within the through hole.

[0019] In the above technical solution, by having at least a portion of the main body disposed within the through hole, the main body can be positioned and engaged with the through hole, facilitating the connection between the pressure relief component and the first wall portion.

[0020] In some embodiments of the first aspect of this application, a first groove is provided on one side of the pressure relief component along the thickness direction of the first wall portion, the weak portion is provided on the bottom wall of the first groove, and at least a portion of the first groove is provided on the main body portion; the battery cell further includes a protective member, the protective member is connected to the pressure relief component, the protective member is provided on the side of the bottom wall of the first groove away from the electrode assembly, and has a gap with the bottom wall of the first groove along the thickness direction of the first wall portion.

[0021] In the above technical solution, a first groove is provided on one side of the pressure relief component along the thickness direction of the first wall portion. The weak part is located on the bottom wall of the first groove, thus creating a distance between the weak part and the side facing the groove opening of the first groove. This increases the distance between the weak part and the groove opening, reducing the risk of damage due to structural contact between the weak part and the groove opening side, and improving the reliability of the battery cell. A protective component is located on the side of the bottom wall of the first groove away from the electrode assembly, facilitating its installation. The protective component and the bottom wall of the first groove have a gap along the thickness direction of the first wall portion. This not only protects the weak part but also provides space for the pressure relief component to release the internal pressure of the battery cell, preventing the protective component from interfering with the pressure release of the battery cell and ensuring timely pressure relief of the battery cell, thereby improving its reliability.

[0022] In some embodiments of the first aspect of this application, the main body includes a first body and a first protrusion. Along the thickness direction of the first wall, the first body has a first surface, the first protrusion protrudes from the first surface, the first surface is provided with a first groove, the first groove includes the first groove, and the weak part is provided on the bottom wall of the first groove; the protective member is connected to the end of the first protrusion away from the first surface.

[0023] In the above technical solution, the first protrusion protrudes from the first surface, the first surface is provided with a first groove, and the weak part is provided on the bottom wall of the first groove. The protective member is connected to the end of the first protrusion away from the first surface, so that the gap between the protective member and the weak part is larger along the thickness direction of the first wall. The protective member can not only protect the weak part, but also provide more space for the pressure relief component to release the internal pressure of the battery cell, avoiding the protective member from affecting the pressure relief of the weak part of the battery cell, so that the battery cell can be depressurized in time, and further improving the reliability of the battery cell.

[0024] In some embodiments of the first aspect of this application, the first protrusion surrounds the outer periphery of the opening of the first groove, the first protrusion and the first surface form the second groove, the first groove is disposed on the bottom wall of the second groove, and the first groove includes the second groove or the inner peripheral surface of the first protrusion is flush with the side wall surface of the first groove.

[0025] In the above technical solution, by having the first protrusion surround the outer periphery of the opening of the first groove, the surface of the first protrusion facing away from the first surface is an annular surface surrounding the axis of the through hole. This increases the connection area between the protective component and the first protrusion, improving the stability of the connection between them. If the first protrusion and the first surface form a second groove, and the first groove includes the second groove, then the first and second grooves together form a stepped first groove, which helps improve the thickness uniformity of each part of the pressure relief component. If the inner peripheral surface of the first protrusion is flush with the side wall surface of the first groove, the structure of the pressure relief component is simpler, making it easier to manufacture.

[0026] In some embodiments of the first aspect of this application, the limiting portion includes a second body and a second protrusion. Along the thickness direction of the first wall portion, the body portion has a first surface, the first surface is provided with a first groove, the first groove includes the first groove, the weak portion is provided on the bottom wall of the first groove, the second body has a second surface, the first surface and the second surface are coplanar and connected, the second protrusion protrudes from the second surface, and the protective member is connected to the end of the second protrusion away from the second surface.

[0027] In the above technical solution, the protective component is connected to the end of the second protrusion of the limiting part that is away from the second surface. The first surface of the main body is provided with a first groove that is coplanar with and connected to the second surface. This makes the gap between the protective component and the weak part larger along the thickness direction of the first wall. The protective component can not only protect the weak part, but also provide more space for the pressure relief component to release the internal pressure of the battery cell. This avoids the protective component affecting the pressure relief of the weak part from the internal pressure of the battery cell, so that the battery cell can be depressurized in time, further improving the reliability of the battery cell.

[0028] In some embodiments of the first aspect of this application, the second protrusion surrounds the outer periphery of the opening of the first groove, the second protrusion, the first surface and the second surface form the second groove, the first groove is disposed on the bottom wall of the second groove, and the first groove includes the second groove.

[0029] In the above technical solution, by having the second protrusion surround the outer periphery of the opening of the first groove, the surface of the second protrusion facing away from the first surface is an annular surface surrounding the axis of the through hole. This increases the connection area between the protective component and the second protrusion, improving the stability of the connection between the protective component and the second protrusion. The second protrusion, the first surface, and the second surface form the second groove. The first groove includes the second groove, and the first groove includes the second groove. Thus, the first groove and the second groove together form a stepped first groove, which is beneficial for improving the thickness uniformity of each part of the pressure relief component.

[0030] In some embodiments of the first aspect of this application, the protective member covers the first groove.

[0031] In the above technical solution, by covering the first groove with a protective component, the protective component can better protect the vulnerable part.

[0032] In some embodiments of the first aspect of this application, along the thickness direction of the first wall portion, a second groove is provided on the side of the main body portion opposite to the first groove, and along the width direction of the second groove, the limiting portion and the weak portion are respectively located on both sides of the width direction of the second groove.

[0033] In the above technical solution, by providing a second groove on the side of the main body away from the first groove, and the limiting part and the weak part being located on both sides of the width direction of the second groove, the second groove can form a buffer zone between the limiting part and the weak part, thereby reducing the impact of the force on the main body on the connecting part, further reducing the risk of the connecting part being affected by the unbalanced force on both sides, improving the reliability of the battery cell and extending the service life of the battery cell.

[0034] In some embodiments of the first aspect of this application, the limiting portion abuts against the inner side of the first wall portion along the thickness direction of the first wall portion.

[0035] In the above technical solution, by having the limiting part abut against the inner side of the first wall, i.e., the limiting part is located inside the first wall, the limiting part is housed within the outer casing. This helps to reduce the volume of the battery cell and increase its energy density. By having the limiting part abut against the inner side of the first wall, when the limiting part is subjected to pressure inside the battery cell, the first wall can limit its movement. This improves the pressure relief component's ability to resist internal pressure within the battery cell and enhances its stability under such pressure.

[0036] In some embodiments of the first aspect of this application, at least a portion of the main body is disposed within the through hole, and along the thickness direction of the first wall portion, the main body has a first surface facing away from the electrode assembly, the first wall portion has a third surface facing away from the electrode assembly, the first surface and the third surface are flush, and the second surface and the third surface are connected through the outer surface of the connecting portion.

[0037] In the above technical solution, the first surface of the main body away from the electrode assembly and the third surface of the first wall away from the electrode assembly are flush, which facilitates the connection between the first wall and the pressure relief component at the junction of the first and third surfaces to form a connecting part.

[0038] In some embodiments of the first aspect of this application, the main body includes a first body and a first protrusion. Along the thickness direction of the first wall, the first surface is the surface of the first body facing away from the electrode assembly, and the first protrusion protrudes from the first surface. The battery cell further includes a protective member connected to the end of the first protrusion facing away from the first surface and forming a gap with the weak portion.

[0039] In the above technical solution, by protruding the first protrusion onto the first surface of the first body away from the electrode assembly, and connecting the protective member to the end of the first protrusion away from the first surface, forming a gap with the weak part, the protective member not only protects the weak part but also provides more space for the pressure relief component to release the internal pressure of the battery cell. This prevents the protective member from affecting the pressure relief of the battery cell, allowing the battery cell to release pressure in a timely manner and further improving the reliability of the battery cell. By protruding the first protrusion onto the first surface of the first body away from the electrode assembly, and connecting the protective member to the end of the first protrusion away from the first surface, the first protrusion and the protective member do not occupy space inside the casing, which is beneficial to improving the energy density of the battery cell. The protective member also reduces the risk of the external structure of the battery cell damaging the weak part, thus improving the reliability of the battery cell.

[0040] In some embodiments of the first aspect of this application, a first receiving groove is provided on the side of the first wall portion away from the electrode assembly. The first receiving groove communicates with the through hole. Along the direction from the electrode assembly to the first wall portion, the main body portion does not extend beyond the bottom surface of the first receiving groove.

[0041] In the above technical solution, by ensuring that the main body does not extend beyond the bottom surface of the first receiving tank, the space occupied by the pressure relief component outside the battery cell is reduced, which helps to reduce the volume of the battery cell and increase its energy density. Furthermore, ensuring that the main body does not extend beyond the bottom surface of the first receiving tank also reduces the risk of interference between the pressure relief component and external equipment, thereby reducing the risk of the pressure relief component being subjected to external impacts and ultimately improving the reliability of the battery cell.

[0042] In some embodiments of the first aspect of this application, the bottom surface of the first receiving groove is flush with the surface of the main body furthest from the electrode assembly.

[0043] In the above technical solution, by making the bottom surface of the first receiving groove flush with the surface of the main body furthest from the electrode assembly, a distance is created between the main body and the surface of the first wall portion away from the electrode assembly. This reduces the risk of damage to weak points in the external structure and improves the reliability of the battery cell. The flushness of the bottom surface of the first receiving groove with the surface of the main body furthest from the electrode assembly also reduces the external space occupied by the pressure relief components, which helps to reduce the volume of the battery cell.

[0044] In some embodiments of the first aspect of this application, a second receiving groove is provided on one side of the first wall portion along the thickness direction of the first wall portion. The second receiving groove communicates with the through hole. The limiting part is accommodated in the second receiving groove. Along the thickness direction of the first wall portion, the limiting part abuts against the bottom wall of the second receiving groove.

[0045] In the above technical solution, a second receiving groove is provided on one side of the first wall in the thickness direction, and the limiting part is accommodated in the second receiving groove, which is beneficial to reduce the volume of the battery cell.

[0046] In some embodiments of the first aspect of this application, along the thickness direction of the first wall portion, the first wall portion has a fourth surface closest to the electrode assembly, the second receiving groove is disposed on the fourth surface, and along the direction of the first wall portion pointing towards the electrode assembly, the limiting portion does not extend beyond the fourth surface.

[0047] In the above technical solution, a second receiving groove is provided on the fourth surface of the first wall closest to the electrode assembly in its thickness direction. The limiting part, after being accommodated in the second receiving groove, does not extend beyond the fourth surface. Therefore, the limiting part does not occupy the internal space of the casing, which is beneficial for improving the energy density of the battery cell. Furthermore, the fact that the limiting part does not extend beyond the fourth surface after being accommodated in the second receiving groove also results in a larger distance between the limiting part and the electrode assembly, reducing the risk of damage to the electrode assembly when the first wall and the pressure relief component are connected.

[0048] In some embodiments of the first aspect of this application, the limiting portion abuts against the outer side of the first wall portion along the thickness direction of the first wall portion.

[0049] In the above technical solution, by abutting the limiting part against the outer side of the first wall part, it is convenient to assemble the pressure relief component onto the first wall part.

[0050] In some embodiments of the first aspect of this application, the first wall portion has a fourth surface closest to the electrode assembly along the thickness direction of the first wall portion; the weak portion does not extend beyond the fourth surface.

[0051] In the above technical solution, by ensuring that the weak part does not extend beyond the fourth surface of the first wall closest to the electrode assembly, the space occupied by the pressure relief component inside the casing is reduced or avoided, which is beneficial to improving the energy density of the battery cell. Furthermore, ensuring the weak part does not extend beyond the fourth surface also reduces the risk of interference between the weak part and the electrode assembly, thus improving the reliability of the battery cell.

[0052] In some embodiments of the first aspect of this application, along the thickness direction of the first wall portion, the main body portion does not extend beyond the surface of the limiting portion away from the first wall portion.

[0053] In the above technical solution, by ensuring that the main body does not extend beyond the surface of the limiting part away from the first wall part, it is beneficial to reduce the volume of the battery cell.

[0054] In some embodiments of the first aspect of this application, the limiting portion and the first wall portion are connected to form the connecting portion, and the connecting portion is located inside the outer peripheral surface of the limiting portion.

[0055] In the above technical solution, the connection part is formed by connecting the limiting part and the first wall part, which makes the connection more convenient. The connection part is located on the inner side of the outer peripheral surface of the limiting part, so the pressure relief component can be subjected to the internal pressure of the battery cell on both sides of the connection part along the radial direction of the through hole. This makes the force on both sides of the connection part balanced, reduces the risk of failure of the connection part due to unbalanced force, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0056] In some embodiments of the first aspect of this application, along the thickness direction of the first wall portion, the thickness of the portion of the first wall portion that abuts against the limiting portion is D, and the thickness of the limiting portion is d, where D / 5≤d≤5D; optionally, D / 3≤d≤2D.

[0057] In the above technical solution, by ensuring d ≥ D / 5, the limiting part has sufficient thickness to connect with the first wall, resulting in a larger connection area for the connection formed by the limiting part and the first wall, which is beneficial to improving the connection stability between the pressure relief component and the first wall. When the connection between the first wall and the limiting part is achieved through welding, d ≥ D / 5 can reduce the risk of the limiting part being welded through while ensuring a large molten pool depth, thus improving the connection stability between the first wall and the limiting part, as well as the strength of the laminated area between the limiting part and the first wall. By ensuring d ≤ 5D, the space occupied by the limiting part can be reduced. If the limiting part is located inside the first wall, it can reduce the space occupied by the limiting part inside the casing, increasing the energy density of the battery cell. If the limiting part is located outside the first wall, it can reduce the space occupied by the limiting part outside the battery cell, which is beneficial to reducing the volume of the battery cell. Therefore, D / 5 ≤ d ≤ 5D ensures both good connection stability between the pressure relief component and the first wall and reduces the space occupied by the limiting part. By ensuring d ≥ D / 3, the limiting part has sufficient thickness to connect with the first wall, resulting in a larger connection area and improving the connection stability between the pressure relief component and the first wall. When the connection between the first wall and the limiting part is achieved through welding, d ≥ D / 3 reduces the risk of the limiting part being welded through while ensuring a greater molten pool depth, further improving the connection stability and the strength of the laminated area between the limiting part and the first wall. By ensuring d ≤ 2D, the space occupied by the limiting part can be further reduced. If the limiting part is located inside the first wall, it further reduces the space occupied inside the casing, increasing the energy density of the battery cell. If the limiting part is located outside the first wall, it further reduces the space occupied outside the battery cell, reducing the battery cell volume. Therefore, D / 3 ≤ d ≤ 2D not only improves the connection stability between the pressure relief component and the first wall but also further reduces the space occupied by the limiting part.

[0058] In some embodiments of the first aspect of this application, the housing includes a shell and an end cap, the shell having an opening, the end cap closing the opening, and the end cap being the first wall portion.

[0059] In the above technical solution, the end cap is the first wall portion. By installing the pressure relief component on the end cap, the end cap can be located on the top of the battery cell, which can reduce the risk of electrolyte corrosion of the pressure relief component, improve the working stability of the pressure relief component, and reduce electrolyte seepage into the pressure relief component, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0060] In some embodiments of the first aspect of this application, the housing includes a shell and an end cap, the shell having an opening, the end cap closing the opening, and the shell including the first wall portion.

[0061] In the above technical solution, the housing includes a first wall portion, and the pressure relief component is disposed on the wall portion of the housing, which is beneficial to improving the energy density of the battery cell.

[0062] In some embodiments of the first aspect of this application, the housing includes a bottom wall and a side wall surrounding the bottom wall, the bottom wall being connected to one end of the side wall and the other end of the side wall forming the opening; the bottom wall is the first wall portion.

[0063] In the above technical solution, the bottom wall is the first wall. By setting the pressure relief component on the bottom wall, the risk of the heat released by the pressure relief component damaging other internal structures of the battery cell and causing other problems such as fire and explosion can be reduced, thereby improving the reliability of the battery cell.

[0064] In some embodiments of the first aspect of this application, the housing includes a bottom wall and a side wall surrounding the bottom wall, the bottom wall being connected to one end of the side wall and the other end of the side wall forming the opening; the side wall includes the first wall portion.

[0065] In the above technical solution, the sidewall includes a first wall portion. By setting the pressure relief component on the sidewall, it is beneficial to improve the energy density of the battery cell.

[0066] In some embodiments of the first aspect of this application, the sidewall includes a first sidewall and a second sidewall disposed adjacent to each other, wherein the area of ​​the outer surface of the first sidewall is greater than the area of ​​the outer surface of the second sidewall; and the second sidewall is the first wall portion.

[0067] In the above technical solution, the area of ​​the outer surface of the first sidewall is larger than the area of ​​the outer surface of the second sidewall; the second sidewall is the first wall portion. By setting the pressure relief component on the second sidewall with a smaller outer surface area, when multiple battery cells are stacked, adjacent battery cells will not interfere with each other to relieve pressure, which is beneficial to improving the reliability of the battery cells and the reliability of the battery device including multiple battery cells.

[0068] Secondly, embodiments of this application provide a battery device, including a single battery cell provided in any one of the embodiments of the first aspect.

[0069] In the above technical solution, the battery cell provided in the first aspect embodiment has good reliability, which makes the battery device having the battery cell more reliable.

[0070] Thirdly, embodiments of this application provide an electrical device, including a battery cell provided in any embodiment of the first aspect or a battery device provided in an embodiment of the second aspect.

[0071] In the above technical solutions, the single cell provided in the first aspect embodiment and the battery device provided in the second aspect embodiment both have good reliability, which is beneficial to improving the power reliability of electrical equipment powered by the single cell or the battery device. Attached Figure Description

[0072] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0074] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0075] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0076] Figure 4 is an isometric view of a battery cell provided in some embodiments of this application;

[0077] Figure 5 is a schematic diagram of the first wall portion and the pressure relief component connected according to some embodiments of this application;

[0078] Figure 6 is a cross-sectional view along the P1-P1 direction in Figure 5;

[0079] Figure 7 is a view of the housing provided in some embodiments of this application from another perspective;

[0080] Figure 8 is a cross-sectional view along line P2-P2 in Figure 7;

[0081] Figure 9 is an enlarged view of section A1 in Figure 8;

[0082] Figure 10 is a schematic diagram of the cooperation between pressure relief components and protective components provided in some embodiments of this application;

[0083] Figure 11 is a partial cross-sectional view of a pressure relief component provided in some embodiments of this application;

[0084] Figure 12 is an isometric view of the housing provided in some embodiments of this application;

[0085] Figure 13 is a schematic diagram of the housing provided in some embodiments of this application from another perspective;

[0086] Figure 14 is a cross-sectional view along P3-P3 in Figure 13;

[0087] Figure 15 is an enlarged view of point A2 in Figure 14;

[0088] Figure 16 is a schematic diagram of the cooperation between pressure relief components and protective components provided in some other embodiments of this application;

[0089] Figure 17 is a partial cross-sectional view of a pressure relief component provided in some other embodiments of this application;

[0090] Figure 18 is an isometric view of the housing provided in some embodiments of this application;

[0091] Figure 19 is a schematic diagram of the housing provided in some embodiments of this application from another perspective;

[0092] Figure 20 is a cross-sectional view along P4-P4 in Figure 19;

[0093] Figure 21 is an enlarged view of section A3 in Figure 20;

[0094] Figure 22 is a schematic diagram of the pressure relief component and protective component after being assembled in some embodiments of this application.

[0095] Figure 23 is a partial cross-sectional view of a pressure relief component provided in some other embodiments of this application;

[0096] Figure 24 is an isometric view of the housing provided in some other embodiments of this application;

[0097] Figure 25 is a schematic diagram of the housing provided in some other embodiments of this application from another perspective;

[0098] Figure 26 is a cross-sectional view along P5-P5 in Figure 24;

[0099] Figure 27 is an enlarged view of section A4 in Figure 26;

[0100] Figure 28 is a schematic diagram of the pressure relief component and protective component after being assembled according to some embodiments of this application;

[0101] Figure 29 is a partial cross-sectional view of a pressure relief component provided in some embodiments of this application.

[0102] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing; 12 - Second housing; 20 - Battery cell; 21 - Outer casing; 211 - Housing; 2111 - Opening; 2112 - Side wall; 21121 - First side wall; 21122 - Second side wall; 2113 - Bottom wall; 212 - End cap; 213 - First wall portion; 2131 - Through hole; 2132 - First receiving groove; 21321 - Bottom surface of the first receiving groove; 2133 - Third surface; 2134 - Second receiving groove; 2135 - Fourth surface; 22 - Electrode assembly; 23 - Electrode terminal; 24 - Current collector; 25 - Pressure relief component; 251 - Connection part; 252 - Main body; 2521 - Weak part; 2522 - First part; 2523 - Second part; 25231 - Second region; 25232 - Third region; 2524 - First body; 25241 - First surface; 2525 - First protrusion; 25251 - Inner peripheral surface of the first protrusion; 253 - Limiting part; 2531 - Second body; 25311 - Second surface; 2532 - Second protrusion; 25321 - Inner peripheral surface of the second protrusion; 254 - First groove; 2541 - First slot; 25411 - Side wall of the first slot; 2542 - Second slot; 25421 - Side wall of the second slot; 255 - Second groove; 26 - Protective component; 200 - Controller; 300 - Motor; X - Thickness direction of the first wall. Detailed Implementation

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] In this application, "multiple" means two or more (including two).

[0110] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0111] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0112] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0113] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material 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 active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0115] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, 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 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 positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may 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 oxide may 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 / 3 O2 (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 0.2O2 (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) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0117] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0118] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0119] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, 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 current collector and a negative active material disposed on at least one surface of the negative 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 active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0122] As an example, 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 positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0124] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0125] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0126] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0127] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0128] In some embodiments, the electrolyte salt may include 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.

[0129] In some embodiments, the solvent may include at least one selected from 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 selected from 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.

[0130] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0131] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0132] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0133] As an example, inorganic solid electrolytes may include 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 phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0134] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0135] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0136] In some implementations, the electrode assembly is a stacked structure.

[0137] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0138] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0139] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0140] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0141] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0142] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0143] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0144] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0145] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0146] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0147] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0148] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0149] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cells housed within the housing.

[0150] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0151] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0152] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0153] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0154] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0155] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0156] To improve the reliability of individual battery cells, the outer casing of the battery cell is equipped with a pressure relief component. The outer casing has a through hole, and the pressure relief component covers the through hole. The outer casing and the pressure relief component are connected to form a connection part, which extends to the outer peripheral surface of the pressure relief component. This results in the pressure relief component being subjected to the pressure from inside the battery cell only on the inner side of the connection part (the side closest to the axis of the through hole). This causes an imbalance of forces on both sides of the connection part. One side of the connection part is repeatedly subjected to the internal pressure of the battery cell, which easily leads to connection failure and reduces the reliability of the battery cell.

[0157] In view of this, in order to improve the reliability of the battery cell, this application provides a battery cell including a housing, an electrode assembly, and a pressure relief component; the housing has a first wall portion with a through hole; the electrode assembly is housed within the housing; the pressure relief component is connected to the first wall portion to form a connecting portion, the pressure relief component including a main body portion and a limiting portion, the limiting portion being connected to the main body portion and surrounding at least a portion of the outer periphery of the main body portion, the main body portion being disposed opposite to the through hole, the main body portion having a weak portion, the weak portion being configured to be broken to release the pressure inside the battery cell; along the thickness direction of the first wall portion, the limiting portion abuts against the first wall portion, and in a projection plane perpendicular to the thickness direction of the first wall portion, at least a portion of the orthographic projection of the limiting portion is located outside the orthographic projection of the connecting portion.

[0158] By having the limiting part abut against the first wall in the thickness direction of the first wall, the first wall and the pressure relief component are limited, which facilitates the installation of the pressure relief component on the first wall and improves the force-bearing capacity of the area where the pressure relief component and the first wall abut.

[0159] By placing at least a portion of the orthographic projection of the limiting part in the projection plane perpendicular to the thickness direction of the first wall portion outside the orthographic projection of the connection portion formed by the pressure relief component and the first wall portion, the pressure relief component can be subjected to force on both sides of the connection portion along the radial direction of the through hole. For example, the pressure relief component may be subjected to the internal pressure of the battery cell on both sides of the connection portion along the radial direction of the through hole, or the pressure relief component may be subjected to the external load of the battery cell on both sides of the connection portion along the radial direction of the through hole. This balances the forces on both sides of the connection portion, reduces the risk of failure of the connection portion due to the unbalanced radial forces in the through hole, thereby improving the reliability of the battery cell and extending the service life of the battery cell.

[0160] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0161] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0162] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0163] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0164] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0165] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and a battery cell 20, with the housing 10 used to house the battery cell 20.

[0166] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing 11 and a second housing 12, which are interlocked. The first housing 11 and the second housing 12 can have various shapes, such as cuboids or cylinders. The first housing 11 can be a hollow structure open on one side, and the second housing 12 can also be a hollow structure open on one side. The open side of the second housing 12 interlocks with the open side of the first housing 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing 11 can be a hollow structure open on one side, and the second housing 12 can be a plate-like structure, with the second housing 12 interlocked with the open side of the first housing 11, thus forming a housing 10 with an accommodating space.

[0167] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0168] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0169] Please refer to Figures 3 and 4. Figure 3 is an exploded view of a battery cell 20 provided in some embodiments of this application, and Figure 4 is an isometric view of a battery cell 20 provided in some embodiments of this application. The battery cell 20 may include a housing 21 and an electrode assembly 22, with the electrode assembly 22 housed within the housing 21.

[0170] In some embodiments, the housing 21 may include a housing 211 and an end cap 212, the housing 211 having an opening 2111, and the end cap 212 closing the opening 2111 of the housing 211. Here, "closed" means to cover or shut, and can be either sealed or unsealed.

[0171] The housing 211 is a component used to house the electrode assembly 22. The housing 211 can be a hollow structure with an opening 2111 at one end, or it can be a hollow structure with openings 2111 at both opposite ends. The housing 211 can have various shapes, such as cylindrical or cuboid. The housing 211 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The electrode assembly 22 can be partially or completely located within the housing 211.

[0172] End cap 212 and housing 211 together define a receiving space for accommodating electrode assembly 22 and other components. End cap 212 can be connected to housing 211 by welding, roll sealing, or other methods to close opening 2111 of housing 211. The shape of end cap 212 can be adapted to the shape of housing 211. For example, if housing 211 is a cuboid structure, end cap 212 can be a rectangular plate structure adapted to housing 211; or if housing 211 is a cylindrical structure, end cap 212 can be a circular plate structure adapted to housing 211. The material of end cap 212 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The materials of end cap 212 and housing 211 can be the same or different.

[0173] In an embodiment where the housing 211 has an opening 2111 at one end, one end cap 212 may be provided accordingly. In an embodiment where the housing 211 has openings 2111 at both opposite ends, two end caps 212 may be provided accordingly. The two end caps 212 respectively close the two openings 2111 of the housing 211, and the two end caps 212 and the housing 211 together define the receiving space.

[0174] In some embodiments, the battery cell 20 may further include electrode terminals 23, which are disposed on the housing 21 and are used for electrical connection with the tabs of the electrode assembly 22 to input or output electrical energy of the battery cell 20. The electrode terminals 23 may be disposed on the housing 211 of the housing 21 or on the end cap 212 of the housing 21. The electrode terminals 23 and the tabs may be directly connected, for example, by welding the electrode terminals 23 to the tabs. Alternatively, the electrode terminals 23 and the tabs may be indirectly connected, for example, through a current collector 24. The current collector 24 may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0175] As an example, as shown in Figure 3, one end of the housing 211 forms an opening 2111, and there is one end cap 212 in the housing 21, which closes one opening 2111 of the housing 211. Two electrode terminals 23 are provided on the end cap 212, which are a positive electrode terminal and a negative electrode terminal, respectively. The end of the electrode assembly 22 facing the end cap 212 has a positive electrode tab and a negative electrode tab. The positive electrode terminal is electrically connected to the positive electrode tab, and the negative electrode terminal is electrically connected to the negative electrode tab.

[0176] Referring to Figures 5 and 6, this embodiment of the application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a pressure relief component 25. The housing 21 has a first wall portion 213, and the first wall portion 213 is provided with a through hole 2131. The electrode assembly 22 is accommodated within the housing 21. The pressure relief component 25 is connected to the first wall portion 213 to form a connecting portion 251. The pressure relief component 25 includes a main body portion 252 and a limiting portion 253, which is connected to and surrounds the main body portion 252. At least a portion of the outer periphery of the main body 252 is disposed opposite to the through hole 2131. The main body 252 has a weak portion 2521, which is configured to be broken to release the pressure inside the battery cell 20. Along the thickness direction X of the first wall, the limiting portion 253 abuts against the first wall 213. In the projection plane perpendicular to the thickness direction X of the first wall, at least a portion of the orthographic projection of the limiting portion 253 is located outside the orthographic projection of the connecting portion 251.

[0177] The first wall portion 213 can be any wall portion of the outer shell 21. For example, the first wall portion 213 can be the side wall 2112 or the bottom wall 2113 of the outer shell 211, and the first wall portion 213 can be an end cap 212.

[0178] The through hole 2131 extends through both sides of the thickness direction X of the first wall portion, enabling communication between the interior and exterior of the outer casing 21. The axial direction of the through hole 2131 can be parallel to the thickness direction X of the first wall portion or at an angle to it. The through hole 2131 can have various shapes, such as circular, elliptical, or square.

[0179] The pressure relief component 25 is connected to the first wall portion 213 and covers the through hole 2131 to separate the interior and exterior of the housing 21. The pressure relief component 25 can be broken, thereby allowing the through hole 2131 to connect the interior and exterior of the housing 21.

[0180] Viewed along the thickness direction X of the first wall portion, the projection of the main body portion 252 is located within the through hole 2131. The limiting portion 253 is connected to the surface of the main body portion 252 closest to the hole wall surface of the through hole 2131. The limiting portion 253 can be an annular structure surrounding the main body portion 252, meaning the limiting portion 253 surrounds the outer periphery of the main body portion 252 360°, or the limiting portion 253 surrounds the entire outer periphery of the main body portion 252. Alternatively, the limiting portion 253 can be located within a portion of the main body portion 252 along its circumference, meaning the limiting portion 253 surrounds the outer periphery of the main body portion 252 less than 360°, or the limiting portion 253 surrounds only a portion of the outer periphery of the main body portion 252.

[0181] The main body 252 and the limiting part 253 can be integrally formed, for example, by stamping, casting or other methods to form the pressure relief component 25.

[0182] The main body 252 and the limiting part 253 can also be separate parts connected as one unit, and the main body 252 and the limiting part 253 can be connected by welding, bonding or other methods.

[0183] The weakest part 2521 is the area where the pressure relief component 25 is weakest. The weakest part 2521 is located in the main body 252. Since the main body 252 is positioned opposite to the through hole 2131, the main body 252 can directly bear the pressure inside the battery cell 20. When the pressure or temperature inside the battery cell 20 reaches a threshold, the weakest part 2521 is damaged by the pressure of the battery cell 20. For example, the weakest part 2521 is torn, thereby opening the through hole 2131 in the pressure relief component 25 and releasing the pressure inside the battery cell 20.

[0184] There are several ways to form the weak part 2521. For example, the weak part 2521 can be formed by setting a groove in the main body 252 of the pressure relief component 25, and the bottom wall 2113 of the groove forms the weak part 2521; another example is that the weak part 2521 can also be formed by setting a weaker material in the main body 252.

[0185] Viewed along the thickness direction X of the first wall portion, at least a portion of the limiting portion 253 overlaps with at least a portion of the first wall portion 213. The limiting portion 253 can be located on the side of the first wall portion 213 facing the electrode assembly 22, or it can be located on the side of the first wall portion 213 away from the electrode assembly 22. Figure 9 shows the case where the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, and Figures 27 and 28 show the case where the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22.

[0186] There are various ways to connect the pressure relief component 25 and the first wall portion 213, such as bonding or welding. In the embodiment where the pressure relief component 25 and the first wall portion 213 are welded together, the connecting portion 251 is a solder mark. The connecting portion 251 can be a closed annular structure along the circumference of the through hole 2131, or it can be a non-closed structure extending circumferentially along the through hole 2131.

[0187] In the projection plane perpendicular to the thickness direction X of the first wall portion, the outer side of the orthographic projection of the connecting portion 251 refers to the side of the connecting portion 251 that is away from the axis of the through hole 2131 in the radial direction of the through hole 2131; the inner side of the orthographic projection of the connecting portion 251 refers to the side of the connecting portion 251 that faces the axis of the through hole 2131 in the radial direction of the through hole 2131.

[0188] In the projection plane perpendicular to the thickness direction X of the first wall portion, at least a portion of the orthographic projection of the limiting portion 253 is located outside the orthographic projection of the connecting portion 251. Therefore, along the radial direction of the through hole 2131, there is a distance between the edge of the limiting portion 253 away from the main body portion 252 and the connecting portion 251. Along the radial direction of the through hole 2131, at least a portion of the limiting portion 253 and at least a portion of the main body portion 252 are located on opposite sides of the connecting portion 251. The portion of the limiting portion 253 located on the side of the connecting portion 251 away from the main body portion 252 and the portion of the main body portion 252 located on the side of the connecting portion 251 away from the limiting portion 253 can both be directly or indirectly subjected to the pressure inside the battery cell 20.

[0189] By having the limiting part 253 abut against the first wall part 213 in the thickness direction X of the first wall part, the first wall part 213 and the pressure relief component 25 are limited, which facilitates the installation of the pressure relief component 25 on the first wall part 213 and improves the force-bearing capacity of the area where the pressure relief component 25 and the first wall part 213 abut. By placing at least a portion of the orthographic projection of the limiting part 253 in the projection plane perpendicular to the thickness direction X of the first wall portion outside the orthographic projection of the connecting part 251 formed by the pressure relief member 25 and the first wall portion 213, the pressure relief member 25 can be subjected to force on both sides of the connecting part 251 radially along the through hole 2131. For example, the pressure relief member 25 can be subjected to the internal pressure of the battery cell 20 on both sides of the connecting part 251 radially along the through hole 2131, or the pressure relief member 25 can be subjected to the external load of the battery cell 20 on both sides of the connecting part 251 radially along the through hole 2131. This balances the forces on both sides of the connecting part 251, reducing the risk of failure of the connecting part 251 due to the unbalanced radial forces in the through hole 2131, thereby improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0190] As shown in Figures 5-9, the main body 252 is connected to the first wall 213 to form a connecting part 251.

[0191] The connection methods between the main body 252 and the first wall 213 include, but are not limited to, adhesive connection and welding connection.

[0192] When the main body 252 and the first wall 213 are connected to form a connecting part 251, the connecting part 251 can also be formed by connecting the first wall 213 and the limiting part 253 in the overlapping area. In this case, the pressure relief member 25 and the first wall 213 can form at least two connecting parts 251.

[0193] In some embodiments, the connecting portion 251 formed by the connection of the main body portion 252 and the first wall portion 213 may be at least partially located within the through hole 2131. As shown in Figures 5 and 6, the pressure relief component 25 has a plate-like structure and is located on one side of the thickness direction X of the first wall portion. The main body portion 252 and the first wall portion 213 are connected, and the connecting portion 251 is located within the through hole 2131, connecting the hole wall surface of the through hole 2131 and the surface of the main body portion 252 facing the through hole 2131.

[0194] In other embodiments, the connecting portion 251 formed by the connection of the main body portion 252 and the first wall portion 213 may be at least partially located outside the through hole 2131. For example, as shown in FIG9, the main body portion 252 is inserted into the through hole 2131, and the portion of the main body portion 252 inserted into the through hole is connected to the first wall portion 213 to form the connecting portion 251, at least a portion of which is located within the through hole 2131.

[0195] The connection portion 251 is formed by connecting the main body portion 252 and the first wall portion 213, which improves the connection stability between the pressure relief component 25 and the first wall portion 213. The connection portion 251 also increases the area of ​​the orthographic projection of the limiting portion 253 in the projection plane perpendicular to the thickness direction X of the first wall portion, located outside the connection portion 251. This increases the force-bearing area of ​​the pressure relief component 25 on the outside of the connection portion 251, thereby reducing the difference in force-bearing area between the inner and outer sides of the connection portion 251. This further reduces the force difference between the inner and outer sides of the connection portion 251, making the force on both sides of the connection portion 251 more balanced. This further reduces the risk of failure of the connection portion 251 due to unbalanced forces on both sides, thereby improving the reliability of the battery cell 20 and extending its service life.

[0196] The pressure relief component 25 can also be other structures. For example, as shown in Figures 7-11, in some embodiments, the main body 252 includes a first part 2522 and a second part 2523. The first part 2522 extends at least partially into the through hole 2131. The limiting part 253 and the second part 2523 are respectively connected to the two ends of the first part 2522. The weak part 2521 is disposed in the second part 2523. The first part 2522 and the first wall part 213 are connected to form a connecting part 251.

[0197] In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, as shown in FIG9, the first portion 2522 is inserted from the limiting portion 253 into the through hole 2131 in the direction from the electrode assembly 22 toward the first wall portion 213.

[0198] In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22, the first portion 2522 is inserted into the through hole 2131 from the limiting portion 253 along the direction of the first wall portion 213 toward the electrode assembly 22 (as shown in FIG26).

[0199] The limiting part 253 and the second part 2523 are respectively connected to the two ends of the first part 2522 along the thickness direction of the first wall part 213. The weak part 2521 is provided in the second part 2523.

[0200] The first part 2522 can be a circumferentially closed cylindrical structure along the through hole 2131. Of course, the first part 2522 can also be other structures.

[0201] Part 2523 can be a plate-like structure or a structure formed by bending plates.

[0202] The main body 252 can be an integrally formed structure, that is, the first part 2522 and the second part 2523 are integrally formed. For example, the main body 252 can be formed by stamping, casting, bending and other integral forming methods.

[0203] The first part 2522 and the second part 2523 can also be set up separately and connected. The first part 2522 and the second part 2523 can be welded together, bonded together, etc.

[0204] By extending the first portion 2522 of the main body 252 into the through hole 2131, the first portion 2522 can be positioned and engaged with the through hole 2131, facilitating the connection between the pressure relief component 25 and the first wall portion 213. After extending into the through hole 2131, the first portion 2522 is closer to the first wall portion 213, and the connection between the first portion 2522 and the first wall portion 213 forms the connecting portion 251, making the connection between the pressure relief component 25 and the first wall portion 213 easier. The limiting portion 253 and the second portion 2523 are respectively connected to the two ends of the first portion 2522, and the weak portion 2521 is provided in the second portion 2523. This helps to form a buffer zone between the limiting portion 253 and the second portion 2523 through the first portion 2522, thereby reducing the impact of the force on the second portion 2523 on the connecting portion 251, further reducing the risk of the connecting portion 251 collapsing due to the imbalance of forces on both sides, improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0205] As shown in Figure 9, in some embodiments, the thickness of the first portion 2522 is E, and the thickness of the portion of the first wall portion 213 that abuts against the limiting portion 253 along the thickness direction X of the first wall portion is D, where D / 5≤E≤5D.

[0206] The thickness of the first part 2522 is the wall thickness of the first part 2522 along the radial direction of the through hole 2131.

[0207] Along the thickness direction X of the first wall portion, the portion where the first wall portion 213 overlaps with the limiting portion 253 is the first region, and D is the thickness of the first region.

[0208] For example, E can be D / 5, 0.5D, D, 1.5D, 2D, 2.5D, 3D, 3.5D, 4D, 4.5D, 5D, etc.

[0209] Since the first part 2522 is connected to the first wall 213, E≥D / 5 ensures that the first part 2522 has sufficient thickness to connect with the first wall 213. This facilitates a sufficient connection area for the connecting part 251, improving the connection stability between the first part 2522 and the first wall 213, thereby enhancing the reliability of the battery cell 20. When the connection between the first wall 213 and the first part 2522 is achieved through welding, E≥D / 5 can reduce the risk of the first part 2522 being welded through while ensuring a large molten pool depth, thus improving the connection stability between the first wall 213 and the first part 2522. By E≤5D, the thickness of the first part 2522 is controlled within a reasonable range, reducing the area occupied by the first part 2522 in the through hole 2131. This reduces the risk that the first part 2522 will affect the pressure release from the through hole 2131 inside the battery cell 20, thereby improving the reliability of the battery cell 20. Therefore, by ensuring that D / 5≤E≤5D, the connection between the pressure relief component 25 and the first wall portion 213 can be made more stable, and the impact of the first portion 2522 on the pressure relief of the through hole 2131 can also be reduced.

[0210] In some embodiments, 2D / 3≤E≤3D.

[0211] For example, E can be 2D / 3, 1.1D, 1.2D, 1.3D, 1.4D, 1.6D, 1.7D, 1.8D, 1.9D, 2.1D, 2.2D, 2.3D, 2.4D, 2.6D, 2.7D, 2.8D, 2.9D, 3D, etc.

[0212] By ensuring E ≥ 2D / 3, the connecting portion 251 has a larger connection area, further improving the connection stability between the first part 2522 and the first wall portion 213, thereby further improving the reliability of the battery cell 20. By ensuring E ≤ 3D, the thickness of the first part 2522 is controlled within a smaller range, further reducing the area occupied by the first part 2522 in the through hole 2131, thereby further reducing the risk of the first part 2522 affecting the pressure relief inside the battery cell 20 through the through hole 2131, and improving the reliability of the battery cell 20. Therefore, by ensuring 2D / 3 ≤ E ≤ 3D, the connection between the pressure relief component 25 and the first wall portion 213 is more stable, and the impact of the first part 2522 on the pressure relief of the through hole 2131 is further reduced.

[0213] Please refer to Figure 9. In some embodiments, along the radial direction of the through hole 2131, there is a first distance K between the connecting portion 251 and the surface of the first portion 2522 facing away from the hole wall of the through hole 2131, and the thickness of the limiting portion 253 is d, where d / 10≤K≤4d.

[0214] Along the radial direction of the through hole 2131, the surface of the first portion 2522 facing away from the hole wall of the through hole 2131 is the first inner surface, and the first distance K is the distance between the first inner surface and the connecting portion 251 along the radial direction of the through hole 2131. In some embodiments, the first inner surface may be a part of the groove wall of the second groove 255 described later.

[0215] The thickness d of the limiting part 253 is the dimension of the limiting part 253 along the thickness direction X of the first wall.

[0216] For example, K can be d / 10, d / 5, 0.5d, d, 1.5d, 2d, 2.5d, 3d, 3.5d, 4d, etc.

[0217] By establishing a first distance K between the connecting portion 251 and the surface of the first part 2522 facing away from the hole wall of the through hole 2131 along the radial direction of the through hole 2131, the connecting portion 251 does not extend to the surface of the first part 2522 facing away from the hole wall along the radial direction of the through hole 2131, thus reducing the influence of the connecting portion 251 on the strength of the first part 2522. In particular, when the connecting portion 251 is formed by welding the first wall portion 213 and the pressure relief component 25, the first part 2522 is not welded through, making the connection between the first wall portion 213 and the pressure relief component 25 more stable, and improving the overall strength of the structure formed by the pressure relief component 25 and the first wall portion 213. By ensuring K ≥ d / 10, the first part 2522 maintains good strength after being connected to the first wall 213, which is beneficial for the pressure relief component 25 to have better resistance to external forces. By ensuring K ≤ 4d, the thickness of the first part 2522 is controlled within a reasonable range, reducing the area occupied by the first part 2522 in the through hole 2131, reducing the risk that the first part 2522 will affect the pressure relief inside the battery cell 20 through the through hole 2131, and improving the reliability of the battery cell 20. Therefore, d / 10 ≤ K ≤ 4d ensures that the first part 2522 maintains good strength after being connected to the first wall 213, while also reducing the area occupied by the first part 2522 in the through hole 2131, reducing the risk that the first part 2522 will affect the pressure relief inside the battery cell 20 through the through hole 2131, and improving the reliability of the battery cell 20.

[0218] In some embodiments, d / 5≤K≤3d / 2.

[0219] For example, K can be d / 5, 0.3d, 0.4d, 0.6d, 0.7d, 0.8d, 0.9d, 1.1d, 1.2d, 3d / 2, etc.

[0220] By ensuring that d / 5≤K≤3d / 2, the first part 2522 maintains better strength after being connected to the first wall 213, while also reducing the area occupied by the first part 2522 in the through hole 2131. This further reduces the risk of the first part 2522 affecting the pressure release from the through hole 2131 inside the battery cell 20, thereby improving the reliability of the battery cell 20.

[0221] As shown in FIG9, in some embodiments, the connecting portion 251 extends from the surface of the first wall portion 213 away from the limiting portion 253 toward the limiting portion 253 along the thickness direction X of the first wall portion.

[0222] In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22, the connecting portion 251 extends from the surface of the first wall portion 213 facing the electrode assembly 22 toward the limiting portion 253.

[0223] In an embodiment where the limiting portion 253 is provided on the side of the first wall portion 213 facing the electrode assembly 22, the connecting portion 251 extends from the surface of the first wall portion 213 away from the electrode assembly 22 toward the limiting portion 253.

[0224] The connecting portion 251 may or may not extend to the limiting portion 253. For example, in an embodiment where the first wall portion 213 and the main body portion 252 are connected to form the connecting portion 251, the limiting portion 253 may not extend to the limiting portion 253 along the thickness direction X of the first wall portion. In an embodiment where the first wall portion 213 and the limiting portion 253 are connected to form the connecting portion 251, the limiting portion 253 may extend from the side of the first wall portion 213 away from the limiting portion 253 to the limiting portion 253 along the thickness direction X of the first wall portion, thereby achieving the connection between the first wall portion 213 and the limiting portion 253.

[0225] In an embodiment where the main body 252 includes a first part 2522 and a second part 2523, and the limiting part 253 and the second part 2523 are respectively connected to the two ends of the first part 2522, the connecting part 251 extends from the surface of the first wall 213 away from the limiting part 253 toward the limiting part 253. This facilitates the existence of a distance between the connecting part 251 and the second part 2523 in the thickness direction X of the first wall, thereby reducing damage to the weak part 2521 provided in the second part 2523 during the formation of the connecting part 251.

[0226] By extending the connecting portion 251 from the surface of the first wall portion 213 away from the limiting portion 253 toward the limiting portion 253, the first wall portion 213 and the pressure relief component 25 can be connected from the side of the first wall portion 213 away from the limiting portion 253, making the connection more convenient.

[0227] As shown in Figure 9, in some embodiments, there is a second distance H between the connecting part 251 and the limiting part 253 on the surface away from the first wall part 213, and the thickness of the limiting part 253 is d, where d / 10≤H≤2d.

[0228] For example, H can be d / 10, d / 5, 0.5d, 0.7d, 0.8d, 0.9d, d, 1.1d, 1.2d, 1.3d, 1.4d, 1.5d, 1.6d, 1.7d, 1.8d, 1.9d, 2d, etc.

[0229] Because a second distance H exists between the connecting portion 251 and the surface of the limiting portion 253 facing away from the first wall portion 213, the connecting portion 251 does not extend to the surface of the limiting portion 253 facing away from the first wall portion 213, reducing the impact of the connecting portion 251 on the strength of the limiting portion 253. Especially when the first wall portion 213 and the pressure relief component 25 are welded to form the connecting portion 251, the second distance H between the connecting portion 251 and the surface of the limiting portion 253 facing away from the first wall portion 213 prevents the limiting portion 253 from being welded through. This allows for a more stable connection between the first wall portion 213 and the pressure relief component 25, and improves the overall strength of the structure formed by the pressure relief component 25 and the first wall portion 213. With H ≥ d / 10, the limiting portion 253 maintains good strength after the pressure relief component 25 is connected to the first wall portion 213, which helps improve the pressure relief component 25's ability to resist external forces. By ensuring H ≤ 2d, the distance between the surface of the limiting part 253 away from the first wall part 213 and the connecting part 251 is prevented from being too large, which would result in a small size of the connecting part 251 and consequently, lower connection stability between the pressure relief component 25 and the first wall part 213, thus improving the reliability of the battery cell 20. Therefore, d / 10 ≤ H ≤ 2d ensures that the limiting part 253 maintains good strength after the pressure relief component 25 is connected to the first wall part 213, while also providing sufficient connection area for the connecting part 251, thereby improving the connection stability between the first wall part 213 and the pressure relief component 25 and ultimately enhancing the reliability of the battery cell 20.

[0230] In some embodiments, d / 5 ≤ H ≤ d.

[0231] For example, H can be d / 5, 0.3d, 0.4d, 0.45d, 0.55d, 0.65d, 0.75d, 0.85d, 0.95d, d, etc.

[0232] By ensuring H ≥ d / 5, the limiting part 253 maintains better strength after the pressure relief component 25 is connected to the first wall part 213, which further enhances the pressure relief component 25's ability to resist external forces. By ensuring H ≤ d, the excessive distance between the limiting part 253 and the connecting part 251 is avoided, which would result in a smaller size of the connecting part 251 and lower connection stability between the pressure relief component 25 and the first wall part 213, thus improving the reliability of the battery cell 20. Therefore, d / 5 ≤ H ≤ d ensures that the limiting part 253 has better strength after the pressure relief component 25 is connected to the first wall part 213, while also providing sufficient connection area for the connecting part 251, improving the connection stability between the first wall part 213 and the pressure relief component 25, and consequently improving the reliability of the battery cell 20.

[0233] As shown in FIG9, in some embodiments, the main body 252 is at least partially disposed within the through hole 2131.

[0234] The main body 252 may be partially or entirely located within the through hole 2131. The main body 252 extends from the limiting part 253 into the through hole 2131.

[0235] In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, the main body portion 252 extends into the through hole 2131 in the direction of the electrode assembly 22 pointing towards the first wall portion 213.

[0236] In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22, the main body portion 252 extends into the through hole 2131 along the direction of the first wall portion 213 pointing toward the electrode assembly 22.

[0237] In an embodiment where the main body 252 includes a first portion 2522 and a second portion 2523, along the thickness direction X of the first wall portion, the first portion 2522 may be entirely located within the through hole 2131, or it may be partially located within the through hole 2131; similarly, the second portion 2523 may be entirely located within the through hole 2131, or it may be partially located within the through hole 2131. As shown in FIG9, along the thickness direction X of the first wall portion, the first portion 2522 is entirely located within the through hole 2131, and a portion of the second portion 2523 is located within the through hole 2131.

[0238] Along the thickness direction X of the first wall portion, the end of the main body portion 252 opposite to the limiting portion 253 can extend into a through hole 2131, or it can be located within the through hole 2131. As shown in Figure 9, along the thickness direction X of the first wall portion, the end of the main body portion 252 opposite to the limiting portion 253 extends into a through hole 2131. As shown in Figures 21 and 22, along the thickness direction X of the first wall portion, the end of the main body portion 252 opposite to the limiting portion 253 does not extend into a through hole 2131.

[0239] By having the main body 252 at least partially disposed within the through hole 2131, the main body 252 can be positioned and engaged with the through hole 2131, facilitating the connection between the pressure relief component 25 and the first wall portion 213.

[0240] As shown in Figures 9-11, in some embodiments, a first groove 254 is provided on one side of the pressure relief component 25 along the thickness direction X of the first wall portion, a weak portion 2521 is provided on the bottom wall 2113 of the first groove 254, and at least a portion of the first groove 254 is provided on the main body portion 252; the battery cell 20 also includes a protective member 26, which is connected to the pressure relief component 25. The protective member 26 is provided on the side of the bottom wall 2113 of the first groove 254 away from the electrode assembly 22, and has a gap with the bottom wall 2113 of the first groove 254 along the thickness direction X of the first wall portion.

[0241] The first groove 254 can be disposed on the side of the pressure relief component 25 away from the electrode assembly 22. In other words, the first groove 254 can be recessed from the surface of the pressure relief component 25 away from the electrode assembly 22 toward the direction closer to the electrode assembly 22, and the groove opening of the first groove 254 faces the outside of the battery cell 20.

[0242] The first groove 254 can be provided on the side of the pressure relief component 25 facing the electrode assembly 22. In other words, the first groove 254 can be recessed from the surface of the pressure relief component 25 facing the electrode assembly 22 in the direction away from the electrode assembly 22, and the opening of the first groove 254 faces the interior of the battery cell 20.

[0243] The first groove 254 may be entirely located in the main body portion 252 (as shown in Figures 9-11). Alternatively, the first groove 254 may be partially located in the main body portion 252, with another portion of the first groove 254 located in the limiting portion 253 (as shown in Figures 26-28).

[0244] There are various ways to connect the protective component 26 and the pressure relief component 25, such as the protective component 26 being bonded to the pressure relief component 25 or the protective component 26 being welded to the pressure relief component 25.

[0245] The protective component 26 can be made of a waterproof material, such as a waterproof membrane, to reduce the risk of leakage of the battery cell 20 at the pressure relief component 25. The protective component 26 can also have good air permeability to reduce the risk of it obstructing the pressure relief component 25 from releasing the internal pressure of the battery cell 20.

[0246] The protective component 26 is made of materials including but not limited to polyethylene, polypropylene, and other composite materials.

[0247] A first groove 254 is provided on one side of the pressure relief component 25 along the thickness direction X of the first wall portion. A weak portion 2521 is provided on the bottom wall 2113 of the first groove 254. This creates a distance between the weak portion 2521 and the side facing the opening of the first groove 254, increasing the distance between them and reducing the risk of damage due to structural contact. This improves the reliability of the battery cell 20. A protective component 26 is provided on the side of the bottom wall 2113 of the first groove 254 away from the electrode assembly 22, facilitating its installation. The protective component 26 has a gap with the bottom wall 2113 of the first groove 254 along the thickness direction X of the first wall. This not only protects the weak part 2521, but also provides space for the pressure relief component 25 to release the internal pressure of the battery cell 20. This prevents the protective component 26 from affecting the pressure relief of the weak part 2521, thus enabling the battery cell 20 to release pressure in a timely manner and improving the reliability of the battery cell 20.

[0248] As shown in Figures 10 and 11, in some embodiments, the main body 252 includes a first body 2524 and a first protrusion 2525. Along the thickness direction X of the first wall, the first body 2524 has a first surface 25241, the first protrusion 2525 protrudes from the first surface 25241, the first surface 25241 is provided with a first groove 2541, the first groove 254 includes the first groove 2541, and the weak part 2521 is provided on the bottom wall 2113 of the first groove 2541; the protective member 26 is connected to the end of the first protrusion 2525 that is away from the first surface 25241.

[0249] The first surface 25241 can be the surface of the first body 2524 facing away from the electrode assembly 22. The first protrusion 2525 protrudes from the first surface 25241. Then, along the thickness direction X of the first wall portion, the surface of the first protrusion 2525 facing away from the first surface 25241 can be the surface of the pressure relief component 25 furthest from the electrode assembly 22.

[0250] The first protrusion 2525 can be a protrusion that protrudes from the first surface 25241. The first protrusion 2525 can also be a closed-loop structure that protrudes from the first surface 25241 and is closed along the circumference of the through hole 2131.

[0251] The first protrusion 2525 protrudes from the first surface 25241, and the first surface 25241 is provided with a first groove 2541. The weak part 2521 is provided at the bottom wall 2113 of the groove 2541. The protective member 26 is connected to the end of the first protrusion 2525 away from the first surface 25241, so that the gap between the protective member 26 and the weak part 2521 is larger along the thickness direction X of the first wall. The protective member 26 can not only protect the weak part 2521, but also provide more space for the pressure relief component 25 to release the internal pressure of the battery cell 20. This avoids the protective member 26 affecting the pressure relief of the weak part 2521, so that the battery cell 20 can be depressurized in time, and further improves the reliability of the battery cell 20.

[0252] As shown in Figures 12-17, the first protrusion 2525 surrounds the outer periphery of the opening of the first groove 2541, the first protrusion 2525 and the first surface 25241 form the second groove 2542, the first groove 2541 is disposed on the bottom wall 2113 of the second groove 2542, and the first groove 254 includes the second groove 2542.

[0253] The first surface 25241 is the bottom surface of the second groove 2542, and the first groove 2541 is recessed from the bottom surface of the second groove 2542. The sidewalls 25411 and 25421 of the first groove are connected through the first surface 25241. The first groove 2541 and the second groove 2542 together form a stepped first groove 254. The bottom wall 2113 of the first groove 2541 is also the bottom wall 2113 of the first groove 254.

[0254] The first protrusion 2525 surrounds the outer periphery of the opening of the first groove 2541. The surface of the first protrusion 2525 facing away from the first surface 25241 forms an annular surface surrounding the axis of the through hole 2131. This increases the connection area between the protective member 26 and the first protrusion 2525, improving the stability of the connection. The first protrusion 2525 and the first surface 25241 form the second groove 2542. The first groove 254 includes the second groove 2542. The first groove 2541 and the second groove 2542 together form a stepped first groove 254, which helps improve the thickness uniformity of each part of the pressure relief component 25.

[0255] As shown in Figures 9-11, in some other embodiments, the first protrusion 2525 surrounds the outer periphery of the opening of the first groove 2541, and the inner peripheral surface 25251 of the first protrusion is flush with the side wall surface 25411 of the first groove.

[0256] The inner circumferential surface 25251 of the first protrusion refers to the surface of the first protrusion 2525 close to the axis of the through hole 2131 in the radial direction of the through hole 2131. The inner circumferential surface 25251 of the first protrusion is flush with the side wall surface 25411 of the first groove, which can also be understood as the inner circumferential surface 25251 of the first protrusion and the side wall surface 25411 of the first groove being coplanar.

[0257] In the embodiments shown in Figures 9 and 10, the first wall portion 213 and the main body portion 252 are connected to form a connecting portion 251. Alternatively, the first wall portion 213 and the limiting portion 253 can be connected to form the connecting portion 251. The inner peripheral surface 25251 of the first protrusion is flush with the side wall surface 25411 of the first groove portion, and the first surface 25241 protrudes from the outer peripheral surface of the first protrusion 2525.

[0258] The inner circumferential surface 25251 of the first protrusion is flush with the side wall surface 25411 of the first groove, which makes the structure of the pressure relief component 25 simpler and facilitates the manufacturing and molding of the pressure relief component 25.

[0259] As shown in Figure 29, in some embodiments, the limiting part 253 includes a second body 2531 and a second protrusion 2532. Along the thickness direction X of the first wall, the body part 252 has a first surface 25241, the first surface 25241 is provided with a first groove 2541, the first groove 254 includes the first groove 2541, the weak part 2521 is provided on the bottom wall 2113 of the first groove 2541, the second body 2531 has a second surface 25311, the first surface 25241 and the second surface 25311 are coplanar and connected, and the second protrusion 2532 protrudes from the second surface 25311; the protective member 26 is connected to the end of the second protrusion 2532 that is away from the second surface 25311.

[0260] The first surface 25241 may be the surface of the main body 252 away from the electrode assembly 22, wherein the first surface 25241 may also be the surface of the main body 252 furthest from the electrode assembly 22.

[0261] The second surface 25311 can be the surface of the second body 2531 that is away from the first wall portion 213. In an embodiment where the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22, the second surface 25311 is the surface of the second body 2531 that is away from the electrode assembly 22, and the second protrusion 2532 protrudes from the second surface 25311. Then, along the thickness direction X of the first wall portion, the surface of the second protrusion 2532 that is away from the first surface 25241 can be the surface of the pressure relief member 25 that is furthest from the electrode assembly 22.

[0262] The second protrusion 2532 can be a protrusion that protrudes from the first surface 25241. The second protrusion 2532 can also be a closed-loop structure that protrudes from the first surface 25241 and is closed along the circumference of the through hole 2131.

[0263] The outer peripheral surface of the second protrusion 2532 can be flush with the outer peripheral surface of the second body 2531. The second surface 25311 protrudes from the inner peripheral surface of the second protrusion 2532. The first surface 25241 and the second surface 25311 protrude from the inner peripheral surface 25321 of the second protrusion. In the embodiments of FIG. 27 and FIG. 28, the non-overlapping part of the second body 2531 and the second protrusion 2532 can be connected (welded) to the first wall part 213 to form a connecting part 251.

[0264] The protective member 26 is connected to the end of the second protrusion 2532 of the limiting part 253 that is away from the second surface 25311. The first surface 25241 of the main body part 252 is provided with a first groove 2541 that is coplanar with and connected to the second surface 25311. This makes the gap between the protective member 26 and the weak part 2521 larger along the thickness direction X of the first wall. The protective member 26 can not only protect the weak part 2521, but also provide more space for the pressure relief component 25 to release the internal pressure of the battery cell 20. This avoids the protective member 26 affecting the pressure relief of the weak part 2521, so that the battery cell 20 can be depressurized in time, which further improves the reliability of the battery cell 20.

[0265] In some embodiments, the second protrusion 2532 surrounds the outer periphery of the opening of the first groove 2541, and the second protrusion 2532, the first surface 25241 and the second surface 25311 form the second groove 2542. The first groove 2541 is disposed on the bottom wall 2113 of the second groove 2542, and the first groove 254 includes the second groove 2542.

[0266] The first surface 25241 and the second surface 25311 together form the bottom surface of the second groove 2542. The first groove 2541 is recessed from the bottom surface of the second groove 2542, and the side wall surfaces 25411 and 25421 of the first groove are connected by the first surface 25241 and the second surface 25311. The first groove 2541 and the second groove 2542 together form a stepped first groove 254. The bottom wall 2113 of the first groove 2541 is also the bottom wall 2113 of the first groove 254. The inner peripheral surface 25321 of the second protrusion is the side wall surface 25421 of the second groove.

[0267] The second protrusion 2532 surrounds the outer periphery of the opening of the first groove 2541. The surface of the second protrusion 2532 facing away from the first surface 25241 is an annular surface surrounding the axis of the through hole 2131. This increases the connection area between the protective member 26 and the second protrusion 2532, improving the stability of the connection between the protective member 26 and the second protrusion 2532. The second protrusion 2532, the first surface 25241, and the second surface 25311 form the second groove 2542. The first groove 254 includes the second groove 2542. Thus, the first groove 2541 and the second groove 2542 together form a stepped first groove 254, which helps improve the thickness uniformity of each part of the pressure relief component 25.

[0268] In some embodiments, the protective element 26 covers the first groove 254.

[0269] The protective component 26 is set with the slot corresponding to the first groove 254, and the protective component 26 completely covers the first groove 254.

[0270] By covering the first groove 254 with the protective component 26, the protective component 26 can better protect the vulnerable part 2521.

[0271] As shown in Figures 9-11, in some embodiments, along the thickness direction X of the first wall portion, a second groove 255 is provided on the side of the main body portion 252 opposite to the first groove 254, and along the width direction of the second groove 255, the limiting portion 253 and the weak portion 2521 are respectively located on both sides of the width direction of the second groove 255.

[0272] The first portion 2522 forms one sidewall 2112 of the second groove 255. Along the radial direction of the through hole 2131, the second portion 2523 has a second region 25231 disposed opposite to the first portion 2522, and the second region 25231 forms another sidewall 2112 of the second groove 255. Along the thickness direction X of the first wall portion, the second portion 2523 has a third region 25232 connected to the first portion 2522, and the third region 25232 forms the bottom wall 2113 of the second groove 255.

[0273] By providing a second groove 255 on the side of the main body 252 away from the first groove 254, and with the limiting part 253 and the weak part 2521 located on both sides of the width direction of the second groove 255, the second groove 255 can form a buffer zone between the limiting part 253 and the weak part 2521, thereby reducing the impact of the force on the main body 252 on the connecting part 251, further reducing the risk of the connecting part 251 being damaged due to the imbalance of forces on both sides, improving the reliability of the battery cell 20 and extending the service life of the battery cell 20.

[0274] As shown in Figures 7-10, 12-16, and 18-22, in some embodiments, the limiting portion 253 abuts against the inner side of the first wall portion 213 along the thickness direction X of the first wall portion.

[0275] The limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22. The limiting portion 253 can contact the surface of the first wall portion 213 facing the electrode assembly 22. The surface of the first wall portion 213 that contacts the limiting portion 253 can be the surface of the first wall portion 213 closest to the electrode assembly 22, or it can be a surface of the first wall portion 213 that is not closest to the electrode assembly 22.

[0276] By having the limiting part 253 abut against the inner side of the first wall part 213, i.e., the limiting part 253 is located inside the first wall part 213, the limiting part 253 is housed within the outer casing 21. This helps to reduce the volume of the battery cell 20 and increase its energy density. By having the limiting part 253 abut against the inner side of the first wall part 213, when the limiting part 253 is subjected to pressure inside the battery cell 20, the first wall part 213 can limit the limiting part 253, which helps to improve the ability of the pressure relief component 25 to resist the internal pressure of the battery cell 20, and also improves the stability of the pressure relief component 25 under the action of internal pressure in the battery cell 20.

[0277] In the embodiment where the limiting part 253 abuts against the inner side of the first wall part 213, at least a portion of the main body part 252 is disposed in the through hole 2131. Along the thickness direction X of the first wall part, the main body part 252 has a first surface 25241 facing away from the electrode assembly 22, and the first wall part 213 has a third surface 2133 facing away from the electrode assembly 22. The first surface 25241 and the third surface 2133 are flush, and the second surface 25311 and the third surface 2133 are connected through the outer surface of the connecting part 251.

[0278] The first surface 25241 may or may not be the surface of the main body 252 furthest from the electrode assembly 22. The third surface 2133 may or may not be the surface of the first wall portion 213 furthest from the electrode assembly 22. As shown in FIG21, the first surface 25241 is the surface of the first body 2524 of the main body 252 furthest from the electrode assembly 22, and the third surface 2133 is the surface of the first wall portion 213 furthest from the electrode assembly 22. Therefore, the first wall portion 213 and the main body 252 can be welded together from the outside of the first wall portion 213 at the junction of the first surface 25241 and the third surface 2133 to form a connecting portion 251 (weld mark). The outer surface of the connecting portion 251 (the surface of the connecting portion 251 facing away from the electrode assembly 22) connects the first surface 25241 and the third surface 2133.

[0279] The first surface 25241 of the main body 252 facing away from the electrode assembly 22 and the third surface 2133 of the first wall portion 213 facing away from the electrode assembly 22 are flush, which facilitates the connection of the first wall portion 213 and the pressure relief component 25 at the junction of the first surface 25241 and the third surface 2133 to form a connecting portion 251.

[0280] As shown in Figures 7-22, in some embodiments, the main body 252 includes a first body 2524 and a first protrusion 2525. Along the thickness direction X of the first wall, the first surface 25241 is the surface of the first body 2524 that is away from the electrode assembly 22, and the first protrusion 2525 protrudes from the first surface 25241. The battery cell 20 also includes a protective member 26, which is connected to one end of the first protrusion 2525 that is away from the first surface 25241 and forms a gap with the weak part 2521.

[0281] Along the thickness direction X of the first wall portion, the first surface 25241 is the surface of the first body 2524 furthest from the electrode assembly 22. A first protrusion 2525 protrudes from the first surface 25241, and along the radial direction of the through hole 2131, the first surface 25241 extends beyond the outer peripheral surface and inner peripheral surface 25251 of the first protrusion 2525. The portion of the first surface 25241 protruding from the outer peripheral surface of the first protrusion 2525 is connected to the third surface 2133 via the outer surface of the connecting portion 251.

[0282] The protective member 26 is connected to the end of the first protrusion 2525 that is away from the first surface 25241. The protective member 26 is located on the outside of the battery cell 20, which facilitates the installation of the protective member 26 and prevents the protective member 26 from occupying the space inside the outer casing 21, which is beneficial to improving the energy density of the battery cell 20.

[0283] By protruding the first protrusion 2525 onto the first surface 25241 of the first body 2524 away from the electrode assembly 22, and connecting the protective member 26 to the end of the first protrusion 2525 away from the first surface 25241 and forming a gap with the weak part 2521, the protective member 26 can not only protect the weak part 2521, but also provide more space for the pressure relief component 25 to release the internal pressure of the battery cell 20, thus avoiding the protective member 26 affecting the pressure relief of the weak part 2521, so that the battery cell 20 can be depressurized in time, further improving the reliability of the battery cell 20. By protruding the first protrusion 2525 onto the first surface 25241 of the first body 2524 away from the electrode assembly 22, and connecting the protective member 26 to the end of the first protrusion 2525 away from the first surface 25241, the first protrusion 2525 and the protective member 26 do not occupy the space inside the housing 21, which is beneficial to improving the energy density of the battery cell 20. The protective member 26 can also reduce the risk of damage to the weak part 2521 of the external structure of the battery cell 20, thereby improving the reliability of the battery cell 20.

[0284] In the embodiment where the limiting part 253 abuts against the inner side of the first wall part 213, as shown in Figures 18-22, the first wall part 213 is provided with a first receiving groove 2132 on the side away from the electrode assembly 22. The first receiving groove 2132 communicates with the through hole 2131. Along the direction from the electrode assembly 22 to the first wall part 213, the main body part 252 does not exceed the bottom surface 21321 of the first receiving groove.

[0285] Along the thickness direction X of the first wall portion, the first wall portion 213 has a third surface 2133 facing away from the electrode assembly 22, and a first receiving groove 2132 is recessed from the third surface 2133 toward the electrode assembly 22. The third surface 2133 may be the surface of the first wall portion 213 furthest from the electrode assembly 22, or it may not be the surface of the first wall portion 213 furthest from the electrode assembly 22.

[0286] Along the direction from the electrode assembly 22 to the first wall portion 213, the surface of the main body portion 252 furthest from the electrode assembly 22 may be closer to the electrode assembly 22 than the third surface 2133, or the surface of the main body portion 252 furthest from the electrode assembly 22 may be flush with the third surface 2133, so that the main body portion 252 does not exceed the bottom surface 21321 of the first receiving groove.

[0287] By ensuring that the main body 252 does not extend beyond the bottom surface 21321 of the first receiving groove, the space occupied by the pressure relief component 25 outside the battery cell 20 is reduced, which helps to reduce the volume of the battery cell 20 and increase its energy density. Furthermore, the fact that the main body 252 does not extend beyond the bottom surface 21321 of the first receiving groove also reduces the risk of interference between the pressure relief component 25 and external equipment, thereby reducing the risk of the pressure relief component 25 being subjected to external impacts and ultimately improving the reliability of the battery cell 20.

[0288] As shown in Figures 21 and 22, in some embodiments, the bottom surface 21321 of the first receiving groove is flush with the surface of the main body 252 furthest from the electrode assembly 22.

[0289] The connecting portion 251 can be formed by welding at the junction of the bottom surface 21321 of the first receiving groove and the surface of the main body 252 away from the electrode assembly 22. Alternatively, the limiting portion 253 can be welded to the bottom wall 2113 of the first receiving groove 2132 to form the connecting portion 251.

[0290] By aligning the bottom surface 21321 of the first receiving groove with the surface of the main body 252 furthest from the electrode assembly 22, a distance is created between the main body 252 and the surface of the first wall 213 facing away from the electrode assembly 22. This reduces the risk of external structural damage to the weak point 2521 and improves the reliability of the battery cell 20. The alignment of the bottom surface 21321 of the first receiving groove with the surface of the main body 252 furthest from the electrode assembly 22 also reduces the space occupied by the pressure relief component 25 in the outer casing 21, thus helping to reduce the volume of the battery cell 20.

[0291] In the embodiment where the limiting part 253 abuts against the inner side of the first wall part 213, as shown in Figures 18-22, a second receiving groove 2134 is provided on one side of the first wall part 213 along the thickness direction X of the first wall part. The second receiving groove 2134 communicates with the through hole 2131. The limiting part 253 is accommodated in the second receiving groove 2134. Along the thickness direction X of the first wall part, the limiting part 253 abuts against the bottom wall 2113 of the second receiving groove 2134.

[0292] Along the thickness direction X of the first wall portion, the first wall portion 213 has a fourth surface 2135 facing the electrode assembly 22, and a second receiving groove 2134 is recessed from the fourth surface 2135 in a direction away from the electrode assembly 22. The fourth surface 2135 may be the surface of the first wall portion 213 closest to the electrode assembly 22, or it may not be the surface of the first wall portion 213 closest to the electrode assembly 22.

[0293] The first wall portion 213 has a second receiving groove 2134 on one side in the thickness direction, and the limiting portion 253 is accommodated in the second receiving groove 2134, which helps to reduce the volume of the battery cell 20.

[0294] As shown in Figures 9 and 10, in some embodiments, along the thickness direction of the first wall portion 213, the first wall portion 213 has a fourth surface 2135 that is closest to the electrode assembly 22, and the second receiving groove 2134 is disposed on the fourth surface 2135. Along the direction of the first wall portion 213 pointing to the electrode assembly 22, the limiting portion 253 does not extend beyond the fourth surface 2135.

[0295] Along the direction from the first wall portion 213 to the electrode assembly 22, the surface of the limiting portion 253 closest to the electrode assembly 22 is further away from the electrode assembly 22 relative to the fourth surface 2135, or the surface of the limiting portion 253 closest to the electrode assembly 22 is flush with the fourth surface 2135, so that the limiting portion 253 does not extend beyond the fourth surface 2135 of the second receiving groove 2134 in the direction from the first wall portion 213 to the electrode assembly 22.

[0296] A second receiving groove 2134 is provided on the fourth surface 2135 of the first wall portion 213, which is closest to the electrode assembly 22 in the thickness direction. The limiting portion 253, after being accommodated in the second receiving groove 2134, does not extend beyond the fourth surface 2135. Therefore, the limiting portion 253 does not occupy the internal space of the outer casing 21, which is beneficial for improving the energy density of the battery cell 20. Furthermore, the limiting portion 253, after being accommodated in the second receiving groove 2134, does not extend beyond the fourth surface 2135, and the distance between the limiting portion 253 and the electrode assembly 22 is relatively large, reducing the risk of damage to the electrode assembly 22 when the first wall portion 213 and the pressure relief component 25 are connected.

[0297] As shown in Figures 24-28, in some other embodiments, the limiting portion 253 abuts against the outer side of the first wall portion 213 along the thickness direction X of the first wall portion.

[0298] The limiting portion 253 is located on the side of the first wall portion 213 that is away from the electrode assembly 22. The limiting portion 253 can contact the surface of the first wall portion 213 that is away from the electrode assembly 22. The surface of the first wall portion 213 that contacts the limiting portion 253 can be the surface of the first wall portion 213 that is furthest from the electrode assembly 22, or it can be a surface of the first wall portion 213 that is furthest from the electrode assembly 22.

[0299] By abutting the limiting part 253 against the outer side of the first wall part 213, it is convenient to assemble the pressure relief part 25 onto the first wall part 213.

[0300] As shown in Figures 27 and 28, in some embodiments, the first wall portion 213 has a fourth surface 2135 closest to the electrode assembly 22 along the thickness direction of the first wall portion 213; the weak portion 2521 does not extend beyond the fourth surface 2135.

[0301] In the thickness direction of the first wall portion 213, the surface of the weak portion 2521 closest to the electrode assembly 22 is further away from the electrode assembly 22 relative to the fourth surface 2135, or the surface of the weak portion 2521 closest to the electrode assembly 22 is flush with the fourth surface 2135, so that the weak portion 2521 does not extend beyond the fourth surface 2135.

[0302] By ensuring that the weak portion 2521 does not extend beyond the fourth surface 2135 of the first wall portion 213, which is closest to the electrode assembly 22, the space occupied by the pressure relief component 25 inside the housing 21 is reduced or avoided, which is beneficial to improving the energy density of the battery cell 20. Furthermore, the fact that the weak portion 2521 does not extend beyond the fourth surface 2135 also reduces the risk of interference between the weak portion 2521 and the electrode assembly 22, thus improving the reliability of the battery cell 20.

[0303] As shown in Figures 9-10, 15-16, 21-22, and 27-28, in some embodiments, along the thickness direction X of the first wall portion, the main body portion 252 does not extend beyond the limiting portion 253 away from the surface of the first wall portion 213.

[0304] By ensuring that the main body 252 does not extend beyond the surface of the limiting part 253 away from the first wall part 213, it is beneficial to reduce the volume of the battery cell 20.

[0305] In some embodiments, the limiting portion 253 and the first wall portion 213 are connected to form a connecting portion 251, and the connecting portion 251 is located inside the outer peripheral surface of the limiting portion 253.

[0306] The limiting part 253 and the first wall part 213 are connected in their overlapping area to form a connecting part 251. The limiting part 253 and the first wall part 213 can be bonded together, welded together, etc.

[0307] The connection portion 251 is formed by connecting the limiting portion 253 and the first wall portion 213, making the connection more convenient. Since the connection portion 251 is located inside the outer peripheral surface of the limiting portion 253, the pressure relief component 25 can be subjected to the internal pressure of the battery cell 20 on both sides of the connection portion 251 along the radial direction of the through hole 2131. This ensures that the forces on both sides of the connection portion 251 are balanced, reducing the risk of failure due to unbalanced forces, thereby improving the reliability of the battery cell 20 and extending its service life.

[0308] In some embodiments, along the thickness direction X of the first wall portion, the thickness of the portion of the first wall portion 213 that abuts against the limiting portion 253 is D, and the thickness of the limiting portion 253 is d, where D / 5≤d≤5D;

[0309] For example, d can be D / 5, 0.5D, D, 1.5D, 2D, 2.5D, 3D, 3.5D, 4D, 4.5D, 5D, etc.

[0310] By ensuring that d ≥ D / 5, the limiting part 253 has sufficient thickness to connect with the first wall part 213, resulting in a larger connection area for the connecting part 251 formed by the connection of the limiting part 253 and the first wall part 213. This improves the connection stability between the pressure relief component 25 and the first wall part 213. When the connection between the first wall part 213 and the limiting part 253 is achieved through welding, d ≥ D / 5 reduces the risk of the limiting part 253 being welded through while ensuring a large molten pool depth, thus improving the connection stability between the first wall part 213 and the limiting part 253, as well as the strength of the laminated area between the limiting part 253 and the first wall part 213. By ensuring that d ≤ 5D, the space occupied by the limiting part 253 can be reduced. If the limiting part 253 is located inside the first wall part 213, the space occupied by the limiting part 253 inside the outer casing 21 can be reduced, thereby increasing the energy density of the battery cell 20. If the limiting part 253 is located outside the first wall part 213, the space occupied by the limiting part 253 outside the battery cell 20 can be reduced, which is beneficial to reducing the volume of the battery cell 20. Therefore, D / 5 ≤ d ≤ 5D can not only ensure good connection stability between the pressure relief component 25 and the first wall part 213, but also reduce the space occupied by the limiting part 253.

[0311] In some embodiments, D / 3≤d≤2D.

[0312] For example, d can be D / 3, 0.4D, 0.6D, 0.7D, 0.8D, 0.9D, 1.1D, 1.2D, 1.3D, 1.4D, 1.6D, 1.7D, 1.8D, 1.9D, 2D, etc.

[0313] By ensuring that d ≥ D / 3, the limiting portion 253 has sufficient thickness to connect with the first wall portion 213, resulting in a larger connection area for the connecting portion 251 formed by the connection of the limiting portion 253 and the first wall portion 213. This improves the connection stability between the pressure relief component 25 and the first wall portion 213. When the connection between the first wall portion 213 and the limiting portion 253 is achieved through welding, d ≥ D / 3 reduces the risk of the limiting portion 253 being welded through while ensuring a greater depth of the molten pool, further improving the connection stability between the first wall portion 213 and the limiting portion 253, as well as the strength of the laminated area between the limiting portion 253 and the first wall portion 213. By ensuring that d ≤ 2D, the space occupied by the limiting part 253 can be further reduced. If the limiting part 253 is located inside the first wall part 213, the space occupied by the limiting part 253 inside the outer casing 21 can be further reduced, thereby increasing the energy density of the battery cell 20. If the limiting part 253 is located outside the first wall part 213, the space occupied by the limiting part 253 outside the battery cell 20 can be further reduced, which is beneficial for reducing the volume of the battery cell 20. Therefore, D / 3 ≤ d ≤ 2D not only improves the connection stability between the pressure relief component 25 and the first wall part 213, but also further reduces the space occupied by the limiting part 253.

[0314] As shown in Figures 7-10, in some embodiments, the outer casing 21 includes a housing 211 and an end cap 212. The housing 211 has an opening 2111, and the end cap 212 closes the opening 2111. The end cap 212 is a first wall portion 213.

[0315] If the end cap 212 is the first wall portion 213, then the pressure relief component 25 is disposed on the end cap 212. The end cap 212 and the pressure relief component 25 are separately disposed and connected.

[0316] End cap 212 is the first wall portion 213. By installing pressure relief component 25 on end cap 212, end cap 212 can be located on top of battery cell 20, which can reduce the risk of electrolyte corrosion of pressure relief component 25, improve the working stability of pressure relief component 25, and reduce electrolyte seepage into pressure relief component 25, thereby improving the reliability of battery cell 20 and extending the service life of battery cell 20.

[0317] As shown in Figures 12-16, 18-22, and 24-28, in some embodiments, the housing 21 includes a housing 211 and an end cap 212. The housing 211 has an opening 2111, and the end cap 212 closes the opening 2111. The housing 211 includes a first wall portion 213.

[0318] The first wall portion 213 is part of the wall portion of the housing 211. The first wall portion 213 can be any wall portion other than the end cap 212 of the housing 21.

[0319] The housing 211 includes a first wall portion 213, and the pressure relief component 25 is disposed on the wall portion of the housing 211, which is beneficial to improving the energy density of the battery cell 20.

[0320] As shown in Figures 19-22, in some embodiments, the housing 211 includes a bottom wall 2113 and a side wall 2112 surrounding the bottom wall 2113. The bottom wall 2113 is connected to one end of the side wall 2112, and the other end of the side wall 2112 forms an opening 2111. The bottom wall 2113 is a first wall portion 213.

[0321] The bottom wall 2113 supports the electrode assembly 22 and bears the weight of the electrode assembly 22. The bottom wall 2113 is the first wall portion 213, and the pressure relief component 25 is disposed on the bottom wall 2113. The bottom wall 2113 and the pressure relief component 25 are separately disposed but connected. The side wall 2112 surrounds the outer periphery of the electrode assembly 22.

[0322] By placing the pressure relief component 25 on the bottom wall 2113, the risk of heat released by the pressure relief component 25 damaging other internal structures of the battery cell 20 and causing other problems such as fire and explosion can be reduced, thereby improving the reliability of the battery cell 20.

[0323] As shown in Figures 12-16 and 24-28, in some other embodiments, the housing 211 includes a bottom wall 2113 and a side wall 2112 surrounding the bottom wall 2113. The bottom wall 2113 is connected to one end of the side wall 2112, and the other end of the side wall 2112 forms an opening 2111. The side wall 2112 includes a first wall portion 213.

[0324] Sidewall 2112 surrounds the outer periphery of electrode assembly 22. First wall portion 213 is part of sidewall 2112.

[0325] The side wall 2112 includes a first wall portion 213. By providing the pressure relief component 25 to the side wall 2112, it is beneficial to improve the energy density of the battery cell 20.

[0326] As shown in Figures 12-16 and 24-28, in some embodiments, the sidewall 2112 includes a first sidewall 21121 and a second sidewall 21122 disposed adjacently, the area of ​​the outer surface of the first sidewall 21121 is larger than the area of ​​the outer surface of the second sidewall 21122; the second sidewall 21122 is a first wall portion 213.

[0327] In embodiments where the battery cell 20 is a prismatic battery, the sidewall 2112 includes two first sidewalls 21121 arranged opposite each other along the thickness direction of the battery cell 20 and two second sidewalls 21122 arranged opposite each other along the length direction of the battery cell 20. The outer surface of the first sidewall 21121 refers to the surface of the first sidewall 21121 that faces away from the electrode assembly 22 in the thickness direction of the battery cell 20. The outer surface of the second sidewall 21122 refers to the surface of the second sidewall 21122 that faces away from the electrode assembly 22 in the length direction of the battery cell 20. If the area of ​​the outer surface of the first sidewall 21121 is larger than the area of ​​the outer surface of the second sidewall 21122, then the first sidewall 21121 forms the large surface of the battery cell 20. When multiple battery cells 20 are electrically connected to form a battery module, the multiple battery cells 20 can be stacked along the thickness direction of the battery cell 20, so that the large surfaces of adjacent battery cells 20 are close to each other. With the pressure relief component 25 located on the second side wall 21122, the risk of mutual interference between the pressure relief components 25 of adjacent battery cells 20 is low.

[0328] The area of ​​the outer surface of the first sidewall 21121 is larger than the area of ​​the outer surface of the second sidewall 21122; the second sidewall 21122 is the first wall portion 213. By setting the pressure relief component 25 on the second sidewall 21122 with a smaller outer surface area, when multiple battery cells 20 are stacked, adjacent battery cells 20 will not interfere with each other to relieve pressure of the pressure relief component 25, which is beneficial to improving the reliability of the battery cells 20 and the reliability of the battery device 100 including multiple battery cells 20.

[0329] This application also provides a battery device 100, which includes the battery cell 20 provided in any of the above embodiments.

[0330] The battery device 100 may include multiple battery cells 20, which may be connected in series, parallel, or in a mixed configuration. A mixed configuration refers to a configuration that includes both series and parallel connections.

[0331] The battery cell 20 provided in any of the above embodiments has good reliability, which makes the battery device 100 having the battery cell 20 reliable.

[0332] This application also provides an electrical device, which includes the battery cell 20 or battery device 100 provided in any of the above embodiments.

[0333] The battery cell 20 or battery device 100 is used to provide electrical energy to electrical equipment.

[0334] The individual cell and battery device 100 provided in any of the above embodiments have good reliability, which is beneficial to improving the power reliability of electrical equipment powered by the individual cell 20 or battery device 100.

[0335] This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a pressure relief component 25. The electrode assembly 22 is housed within the housing 21, and a first wall portion 213 of the housing 21 and the pressure relief component 25 are welded together to form a connection portion 251.

[0336] The pressure relief component 25 includes a limiting portion 253 and a main body portion 252. The limiting portion 253 is connected to the outer peripheral surface of the main body portion 252 and has a circumferentially closed structure along the through hole 2131. The main body portion 252 is disposed opposite to the through hole 2131 of the first wall portion 213. The main body portion 252 has a weak portion 2521, which is configured to be broken to release the pressure inside the battery cell 20. A portion of the main body portion 252 is inserted into the through hole 2131.

[0337] The first wall portion 213 is either the end cap 212 of the outer casing 21, or the bottom wall 2113 or the side wall 2112 of the casing 211. The main body portion 252 is inserted into the through hole 2131. Along the thickness direction X of the first wall portion, a first groove 254 is provided on the side of the main body portion 252 away from the electrode assembly 22. Along the thickness direction X of the first wall portion, a protective member 26 is connected to the surface of the pressure relief member 25 furthest from the electrode assembly 22, and the protective member 26 covers the first groove 254.

[0338] Along the thickness direction X of the first wall portion, the first wall portion 213 has a fourth surface 2135 closest to the electrode assembly 22. The fourth surface 2135 is provided with a second receiving groove 2134, and the limiting portion 253 is received within the second receiving groove 2134. Along the thickness direction X of the first wall portion, the limiting portion 253, the main body portion 252, and the weak portion 2521 do not extend beyond the fourth surface 2135.

[0339] The main body 252 and the first wall 213 are welded from the side of the first wall 213 away from the electrode assembly 22 to form a connecting portion 251 (solder mark) and / or the first wall 213 and the limiting portion 253 are welded to form a connecting portion 251 (solder mark). Each connecting portion 251 is located inside the limiting portion 253, that is, in the projection plane perpendicular to the thickness direction X of the first wall, at least a portion of the orthographic projection of the limiting portion 253 is located outside the orthographic projection of each connecting portion 251.

[0340] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

Claims

1. A single battery cell, comprising: The outer casing has a first wall portion, and the first wall portion is provided with a through hole; Electrode assembly, housed within the housing; A pressure relief component is connected to the first wall portion to form a connection portion. The pressure relief component includes a main body portion and a limiting portion. The limiting portion is connected to the main body portion and surrounds at least a portion of the outer periphery of the main body portion. The main body portion is disposed opposite to the through hole. The main body portion has a weak portion. The weak portion is configured to be broken to release the pressure inside the battery cell. Wherein, along the thickness direction of the first wall portion, the limiting portion abuts against the first wall portion, and in the projection plane perpendicular to the thickness direction of the first wall portion, at least a portion of the orthographic projection of the limiting portion is located outside the orthographic projection of the connecting portion.

2. The battery cell as described in claim 1, wherein, The main body portion is connected to the first wall portion to form the connecting portion.

3. The battery cell as described in claim 2, wherein, The main body includes a first part and a second part, the first part extending at least partially into the through hole, the limiting part and the second part being respectively connected to both ends of the first part, and the weak part being disposed in the second part; The first part and the first wall portion are connected to form the connecting portion.

4. The battery cell as described in claim 3, wherein, The thickness of the first part is E, and the thickness of the part of the first wall that abuts against the limiting part along the thickness direction of the first wall is D, where D / 5≤E≤5D; optionally, 2D / 3≤E≤3D.

5. The battery cell as described in claim 3 or 4, wherein, Along the radial direction of the through hole, there is a first distance K between the connecting portion and the surface of the first portion facing away from the hole wall of the through hole, and the thickness of the limiting portion is d, where d / 10≤K≤4d; optionally, d / 5≤K≤3d / 2.

6. The battery cell according to any one of claims 1-5, wherein, Along the thickness direction of the first wall portion, the connecting portion extends from the surface of the first wall portion away from the limiting portion toward the limiting portion.

7. The battery cell as described in claim 6, wherein, There is a second distance H between the connecting part and the surface of the limiting part that is away from the first wall part, and the thickness of the limiting part is d, where d / 10≤H≤2d; optionally, d / 5≤H≤d.

8. The battery cell according to any one of claims 1-7, wherein, The main body is at least partially disposed within the through hole.

9. The battery cell according to any one of claims 1-8, wherein, Along the thickness direction of the first wall portion, a first groove is provided on one side of the pressure relief component, the weak portion is provided on the bottom wall of the first groove, and at least a portion of the first groove is provided on the main body portion; The battery cell also includes a protective component connected to the pressure relief component. The protective component is disposed on the side of the bottom wall of the first groove away from the electrode assembly and has a gap with the bottom wall of the first groove along the thickness direction of the first wall portion.

10. The battery cell as described in claim 9, wherein, The main body includes a first body and a first protrusion. Along the thickness direction of the first wall, the first body has a first surface, the first protrusion protrudes from the first surface, the first surface is provided with a first groove, the first groove includes the first groove, and the thin wall is provided on the bottom wall of the first groove. The protective component is connected to the end of the first protrusion that is away from the first surface.

11. The battery cell as claimed in claim 10, wherein, The first protrusion surrounds the outer periphery of the opening of the first groove, the first protrusion and the first surface form the second groove, the first groove is disposed on the bottom wall of the second groove, and the first groove includes the second groove or the inner peripheral surface of the first protrusion is flush with the side wall surface of the first groove.

12. The battery cell as described in claim 9, wherein, The limiting part includes a second body and a second protrusion. Along the thickness direction of the first wall, the main body has a first surface, the first surface is provided with a first groove, the first groove includes the first groove, and the weak part is provided on the bottom wall of the first groove. The second body has a second surface, the first surface and the second surface are coplanar and connected, and the second protrusion protrudes from the second surface. The protective component is connected to the end of the second protrusion that is away from the second surface.

13. The battery cell as described in claim 12, wherein, The second protrusion surrounds the outer periphery of the opening of the first groove, the second protrusion, the first surface and the second surface form the second groove, the first groove is disposed on the bottom wall of the second groove, and the first groove includes the second groove.

14. The battery cell according to any one of claims 9-13, wherein, The protective component covers the first groove.

15. The battery cell according to any one of claims 9-14, wherein along the thickness direction of the first wall portion, a second groove is provided on the side of the main body portion opposite to the first groove, and along the width direction of the second groove, the limiting portion and the weak portion are respectively located on both sides of the width direction of the second groove.

16. The battery cell according to any one of claims 1-15, wherein, Along the thickness direction of the first wall portion, the limiting portion abuts against the inner side of the first wall portion.

17. The battery cell as claimed in claim 16, wherein, At least a portion of the main body is disposed within the through hole. Along the thickness direction of the first wall portion, the main body has a first surface facing away from the electrode assembly, and the first wall portion has a third surface facing away from the electrode assembly. The first surface and the third surface are flush, and the second surface and the third surface are connected through the outer surface of the connecting portion.

18. The battery cell as claimed in claim 17, wherein, The main body includes a first body and a first protrusion. Along the thickness direction of the first wall, the first surface is the surface of the first body that is away from the electrode assembly, and the first protrusion protrudes from the first surface. The battery cell also includes a protective component, which is connected to the end of the first protrusion that is away from the first surface and forms a gap with the weak part.

19. The battery cell as claimed in claim 16, wherein, A first receiving groove is provided on the side of the first wall portion away from the electrode assembly. The first receiving groove communicates with the through hole. Along the direction from the electrode assembly to the first wall portion, the main body portion does not extend beyond the bottom surface of the first receiving groove.

20. The battery cell as claimed in claim 19, wherein, The bottom surface of the first receiving groove is flush with the surface of the main body furthest from the electrode assembly.

21. The battery cell according to any one of claims 1-20, wherein, Along the thickness direction of the first wall portion, a second receiving groove is provided on one side of the first wall portion. The second receiving groove communicates with the through hole. The limiting part is accommodated in the second receiving groove. Along the thickness direction of the first wall portion, the limiting part abuts against the bottom wall of the second receiving groove.

22. The battery cell as claimed in claim 21, wherein, Along the thickness direction of the first wall portion, the first wall portion has a fourth surface closest to the electrode assembly, and the second receiving groove is disposed on the fourth surface. Along the direction of the first wall portion pointing towards the electrode assembly, the limiting portion does not extend beyond the fourth surface.

23. The battery cell according to any one of claims 1-15, wherein, Along the thickness direction of the first wall portion, the limiting portion abuts against the outer side of the first wall portion.

24. The battery cell according to any one of claims 1-23, wherein, Along the thickness direction of the first wall portion, the first wall portion has a fourth surface that is closest to the electrode assembly; The weak portion does not extend beyond the fourth surface.

25. The battery cell according to any one of claims 1-24, wherein, Along the thickness direction of the first wall portion, the main body portion does not extend beyond the limiting portion away from the surface of the first wall portion.

26. The battery cell as claimed in claim 1, wherein, The limiting part and the first wall part are connected to form the connecting part, and the connecting part is located inside the outer peripheral surface of the limiting part.

27. The battery cell according to any one of claims 1-26, wherein, Along the thickness direction of the first wall portion, the thickness of the portion of the first wall portion that abuts against the limiting portion is D, and the thickness of the limiting portion is d, where D / 5≤d≤5D; optionally, D / 3≤d≤2D.

28. The battery cell according to any one of claims 1-27, wherein, The outer casing includes a housing and an end cap, the housing having an opening, the end cap closing the opening, and the end cap being the first wall portion.

29. The battery cell according to any one of claims 1-28, wherein, The housing includes a shell and an end cap, the shell having an opening, the end cap closing the opening, and the shell including the first wall portion.

30. The battery cell as described in claim 29, wherein, The housing includes a bottom wall and a side wall surrounding the bottom wall, the bottom wall being connected to one end of the side wall and the other end of the side wall forming the opening; The bottom wall is the first wall portion.

31. The battery cell as described in claim 30, wherein, The housing includes a bottom wall and a side wall surrounding the bottom wall, the bottom wall being connected to one end of the side wall and the other end of the side wall forming the opening; The sidewall includes the first wall portion.

32. The battery cell as described in claim 31, wherein, The sidewall includes a first sidewall and a second sidewall arranged adjacent to each other, wherein the area of ​​the outer surface of the first sidewall is greater than the area of ​​the outer surface of the second sidewall. The second sidewall is the first wall portion.

33. A battery device comprising a battery cell as described in any one of claims 1-32.

34. An electrical device comprising a battery cell as described in any one of claims 1-32 or a battery device as described in claim 33.

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