Battery monomer, battery device and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly and a pressure relief component, the shell is provided with a first wall part, and the first wall part is provided with a through hole; the pressure relief component is connected with the first wall part to form a connecting part, the pressure relief component comprises a main body part and a limiting part, the limiting part is connected with the main body part and surrounds the periphery of the main body part, and the main body part is arranged opposite to the through hole and is provided with a weak part; in the thickness direction of the first wall part, the limiting part abuts against the first wall part, in the projection plane perpendicular to the thickness direction of the first wall part, at least part of the orthographic projection of the limiting part is located on the outer side of the orthographic projection of the connecting part, the pressure relief component can bear force on the two sides, in the radial direction of the through hole, of the connecting part, and therefore the stress on the two sides of the connecting part is balanced; and the risk of failure caused by unbalanced radial stress of the connecting part in the through hole is reduced, so that the reliability of the battery monomer is improved, and the service life of the battery monomer is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery device and a power utilization device. BACKGROUND

[0002] Batteries are widely used in new energy vehicles, electronic devices and other fields. As the demand for batteries is increasing, higher reliability of batteries is required. CONTENT OF THE INVENTION

[0003] The present application provides a battery monomer, a battery device and a power utilization device, which can improve the reliability of the battery monomer.

[0004] In a first aspect, the present application provides a battery monomer, comprising a shell, an electrode assembly and a pressure relief component; the shell has a first wall portion, and the first wall portion is provided with a through hole; the electrode assembly is contained in the shell; the pressure relief component is connected with the first wall portion to form a connecting portion, and the pressure relief component comprises a main body portion and a limiting portion, the limiting portion is connected with the main body portion and surrounds at least part of the outer periphery of the main body portion, the main body portion is arranged opposite to the through hole, and the main body portion has a weak portion configured to be damaged to release the pressure inside the battery monomer; 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 part 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 limiting portion against the first wall portion along the thickness direction of the first wall portion, the first wall portion and the pressure relief component form a limiting portion, which facilitates the installation of the pressure relief component on the first wall portion and improves the stress capacity of the abutting area of the pressure relief component and the first wall portion. By locating at least part of the orthographic projection of the limiting portion outside the orthographic projection of the connecting portion 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 stressed on both sides of the connecting portion along the radial direction of the through hole, such as the pressure relief component being stressed by the internal pressure of the battery monomer on both sides of the connecting portion along the radial direction of the through hole or the pressure relief component being stressed by the external load of the battery monomer on both sides of the connecting portion along the radial direction of the through hole. This balances the stress on both sides of the connecting portion, reduces the risk of failure of the connecting portion due to unbalanced stress in the radial direction of the through hole, and thus improves the reliability of the battery monomer and prolongs the service life of the battery monomer.

[0006] In some embodiments of the first aspect of the present application, the main body portion and the first wall portion form the connecting portion.

[0007] In the technical solution, the main body part and the first wall part are connected to form the connecting part, so that the connection stability of the pressure relief part and the first wall part is better. The main body part and the first wall part are connected to form the connecting part, so that the normal projection of the limiting part in the projection plane perpendicular to the thickness direction of the first wall part is located in the area outside the connecting part, thereby increasing the stress area of the pressure relief part outside the connecting part, reducing the stress area difference of the pressure relief part inside and outside the connecting part, further reducing the stress difference of the pressure relief part inside and outside the connecting part, so that the stress of the pressure relief part on both sides of the connecting part tends to be balanced, further reducing the risk of failure of the connecting part due to unbalanced stress on both sides, thereby improving the reliability of the battery monomer and prolonging the service life of the battery monomer.

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

[0009] In the technical solution, the first part of the main body part extends into the through hole, so that the first part can be positioned and matched with the through hole, facilitating the connection of the pressure relief part and the first wall part. After the first part extends into the through hole, the first part is closer to the first wall part, and the first part and the first wall part are connected to form the connecting part, so that the connection difficulty of the pressure relief part and the first wall part is smaller. The limiting part and the second part are respectively connected to two ends of the first part, and the weak part is arranged in the second part, which is conducive to forming a buffer zone between the limiting part and the second part through the first part, thereby reducing the influence of the stress of the second part on the connecting part, further reducing the risk of the connecting part due to unbalanced stress on both sides, improving the reliability of the battery monomer and prolonging the service life of the battery monomer.

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

[0011] In the technical solution, the first part is connected with the first wall portion, E is greater than or equal to D / 5, so that the first part has sufficient thickness to be connected with the first wall portion, which is conducive to the connection portion having sufficient connection area, improves the connection stability of the first part and the first wall portion, and thus improves the reliability of the battery cell. In the case of connecting the first wall portion and the first part by welding, E is greater than or equal to D / 5, which can reduce the risk of the first part being welded through while ensuring a large depth of the molten pool, and improve the connection stability of the first wall portion and the first part. E is less than or equal to 5D, which controls the thickness of the first part within a reasonable range, reduces the area of the through hole occupied by the first part, reduces the risk of the first part affecting the pressure relief of the battery cell from the through hole, and improves the reliability of the battery cell. Therefore, by D / 5≤E≤5D, the connection stability of the pressure relief component and the first wall portion can be improved, and the influence of the first part on the pressure relief of the through hole can be reduced. Further, E is greater than or equal to 2D / 3, which is conducive to the connection portion having a larger connection area, further improves the connection stability of the first part and the first wall portion, and thus further improves the reliability of the battery cell. E is less than or equal to 3D, which controls the thickness of the first part within a smaller range, further reduces the area of the through hole occupied by the first part, and thus further reduces the risk of the first part affecting the pressure relief of the battery cell from the through hole, and improves the reliability of the battery cell. Therefore, by 2D / 3≤E≤3D, the connection stability of the pressure relief component and the first wall portion can be further improved, and the influence of the first part on the pressure relief of the through hole can be further reduced.

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

[0013] In the technical solution, the first distance K is provided between the connecting portion and the surface of the first portion away from the hole wall surface of the through hole along the radial direction of the through hole, so that the connecting portion does not extend to the surface of the first portion away from the hole wall surface along the radial direction of the through hole, thereby reducing the influence of the connecting portion on the strength of the first portion. In particular, when the first wall portion and the pressure relief component are welded to form the connecting portion, the first distance K is provided between the connecting portion and the surface of the first portion away from the hole wall surface along the radial direction of the through hole, so that the first portion is not welded through, thereby making the connection between the first wall portion and the pressure relief component more stable and the strength of the overall structure formed by the pressure relief component and the first wall portion better. The first distance K is greater than or equal to d / 10, so that the first portion still has good strength after being connected to the first wall portion, thereby helping to improve the ability of the pressure relief component to resist external force. The first distance K is less than or equal to 4d, thereby helping to control the thickness of the first portion within a reasonable range, reducing the area of the first portion occupying the through hole, reducing the risk that the first portion affects the pressure relief of the battery monomer from the through hole, and improving the reliability of the battery monomer. Therefore, d / 10≤K≤4d, so that the first portion still has good strength after being connected to the first wall portion, and the area of the first portion occupying the through hole is reduced, the risk that the first portion affects the pressure relief of the battery monomer from the through hole is reduced, and the reliability of the battery monomer is improved. Further, d / 5≤K≤3d / 2, so that the first portion still has better strength after being connected to the first wall portion, and the area of the first portion occupying the through hole is further reduced, thereby further reducing the risk that the first portion affects the pressure relief of the battery monomer from the through hole, and improving the reliability of the battery monomer.

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

[0015] In the technical solution, the connecting portion extends from the surface of the first wall portion away from the limiting portion to the limiting portion, so that the first wall portion and the pressure relief component can be connected from the side of the first wall portion away from the limiting portion, thereby making the connection more convenient.

[0016] In some embodiments of the first aspect of the application, a second distance H is provided 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, d / 10≤H≤2d; optionally, d / 5≤H≤d.

[0017] In the technical solution, the second distance H exists between the connecting portion and the surface of the limiting portion away from the first wall portion, so that the connecting portion does not extend to the surface of the limiting portion away from the first wall portion, the influence of the connecting portion on the strength of the limiting portion is reduced, especially in the case that the first wall portion and the pressure relief component are welded to form the connecting portion, the second distance H exists between the connecting portion and the surface of the limiting portion away from the first wall portion, so that the limiting portion is not welded through, the connection between the first wall portion and the pressure relief component is more stable, and the strength of the overall structure formed by the pressure relief component and the first wall portion is better. By H≥d / 10, the limiting portion still has good strength after the pressure relief component is connected with the first wall portion, which is beneficial to improve the ability of the pressure relief component to resist external force. By H≤2d, the distance between the surface of the limiting portion away from the first wall portion and the connecting portion is not too large, so that the size of the connecting portion is small, which leads to low connection stability of the pressure relief component and the first wall portion, and is beneficial to improve the reliability of the battery monomer. Therefore, d / 10≤H≤2d, so that the limiting portion still has good strength after the pressure relief component is connected with the first wall portion, and the connecting portion has sufficient connection area, which improves the connection stability of the first wall portion and the pressure relief component, and further improves the reliability of the battery monomer. By H≥d / 5, the limiting portion still has better strength after the pressure relief component is connected with the first wall portion, which is beneficial to further improve the ability of the pressure relief component to resist external force. By H≤d, the distance between the limiting portion and the connecting portion is not too large, so that the size of the connecting portion is small, which leads to low connection stability of the pressure relief component and the first wall portion, and is beneficial to improve the reliability of the battery monomer. Therefore, d / 5≤H≤d, so that the limiting portion has better strength after the pressure relief component is connected with the first wall portion, and the connecting portion has sufficient connection area, which improves the connection stability of the first wall portion and the pressure relief component, and further improves the reliability of the battery monomer.

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

[0019] In the technical solution, the main body portion is at least partially arranged in the through hole, so that the main body portion can be positioned and matched with the through hole, which facilitates the connection of the pressure relief component and the first wall portion.

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

[0021] In the technical solution, the first groove is arranged on one side of the pressure relief component along the thickness direction of the first wall portion, and the weak portion is arranged on the groove bottom wall of the first groove. The weak portion has a distance from the side facing the slot opening of the first groove, the distance between the weak portion and the slot opening of the first groove is increased, the risk that the weak portion is damaged due to the structural contact of the weak portion with the slot opening of the first groove is reduced, and the reliability of the battery monomer is improved. The protective piece is arranged on the side of the groove bottom wall of the first groove away from the electrode assembly, and the protective piece is arranged conveniently. The protective piece has a gap with the groove bottom wall of the first groove along the thickness direction of the first wall portion, which can protect the weak portion and provide space for the pressure relief component to release the internal pressure of the battery monomer, avoids the influence of the protective piece on the weak portion to release the internal pressure of the battery monomer, and enables the battery monomer to release pressure in time, thereby improving the reliability of the battery monomer.

[0022] In some embodiments of the first aspect of the application, the main body portion includes a first body and a first protruding portion. Along the thickness direction of the first wall portion, the first body has a first surface, and the first protruding portion protrudes from the first surface. The first surface is provided with a first groove portion, the first groove includes the first groove portion, and the weak portion is arranged on the groove bottom wall of the first groove portion. The protective piece is connected to one end of the first protruding portion away from the first surface.

[0023] In the technical solution, the first protruding portion protrudes from the first surface, the first surface is provided with a first groove portion, the weak portion is arranged on the groove bottom wall of the first groove portion, and the protective piece is connected to one end of the first protruding portion away from the first surface. Along the thickness direction of the first wall portion, the gap between the protective piece and the weak portion is larger, the protective piece can protect the weak portion and provide more space for the pressure relief component to release the internal pressure of the battery monomer, the influence of the protective piece on the weak portion to release the internal pressure of the battery monomer is avoided, the battery monomer can release pressure in time, and the reliability of the battery monomer is further improved.

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

[0025] In the technical solution, the first protruding part is arranged around the outer periphery of the slot of the first slot part, the surface of the first protruding part away from the first surface is an annular surface arranged around the axis of the through hole, the connecting area of the protective part and the first protruding part is increased, and the stability of the connection between the protective part and the first protruding part is improved. If the first protruding part and the first surface form a second slot part, and the first groove includes the second slot part, the first slot part and the second slot part jointly form a first groove in a stepped shape, and the thickness uniformity of each part of the pressure relief component is improved.

[0026] In some embodiments of the first aspect of the application, the limiting part includes a second body and a second protruding part, the main body part has a first surface along the thickness direction of the first wall part, the first surface is provided with a first slot part, the first groove includes the first slot part, the weak part is arranged at the slot bottom wall of the first slot part, the second body has a second surface, the first surface and the second surface are coplanar and connected, and the second protruding part is protruding from the second surface; the protective part is connected to one end of the second protruding part away from the second surface.

[0027] In the technical solution, the protective part is connected to one end of the second protruding part of the limiting part away from the second surface, the first surface of the main body part is provided with a first slot part and is coplanar and connected with the second surface, so that the gap between the protective part and the weak part is larger along the thickness direction of the first wall part. The protective part 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, so as to avoid the influence of the protective part on the weak part releasing the internal pressure of the battery cell, so that the battery cell can be timely relieved, and the reliability of the battery cell is further improved.

[0028] In some embodiments of the first aspect of the application, the second protruding part is arranged around the outer periphery of the slot of the first slot part, the second protruding part, the first surface and the second surface form the second slot part, the first slot part is arranged at the slot bottom wall of the second slot part, and the first groove includes the second slot part.

[0029] In the technical solution, the second protruding part is arranged around the outer periphery of the slot of the first slot part, the surface of the second protruding part away from the first surface is an annular surface arranged around the axis of the through hole, the connecting area of the protective part and the second protruding part is increased, and the stability of the connection between the protective part and the second protruding part is improved. The second protruding part, the first surface and the second surface form the second slot part, the first groove includes the second slot part, the first groove includes the second slot part, the first slot part and the second slot part jointly form a first groove in a stepped shape, and the thickness uniformity of each part of the pressure relief component is improved.

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

[0031] In the above technical solution, the protective member covers the first groove, so that the protective member can better protect the weak part.

[0032] In some embodiments of the first aspect of the present application, along the thickness direction of the first wall part, the second groove is arranged on the side of the main part away from the first groove, and the limiting part and the weak part are respectively located on both sides of the width direction of the second groove.

[0033] In the above technical solution, by arranging the second groove on the side of the main part away from the first groove, and arranging the limiting part and the weak part 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 influence of the stress on the main part on the connecting part, further reducing the risk of the connecting part being unbalanced due to the stress on both sides, improving the reliability of the battery monomer, and prolonging the service life of the battery monomer.

[0034] In some embodiments of the first aspect of the present application, along the thickness direction of the first wall part, the limiting part is in contact with the inner side of the first wall part.

[0035] In the above technical solution, by arranging the limiting part in contact with the inner side of the first wall part, i.e. arranging the limiting part on the inner side of the first wall part, the limiting part is accommodated in the shell, which is beneficial to reducing the volume of the battery monomer and improving the energy density of the battery monomer. By arranging the limiting part in contact with the inner side of the first wall part, when the limiting part bears the internal pressure of the battery monomer, the first wall part can limit the limiting part, which is beneficial to improving the ability of the pressure relief component to resist the internal pressure of the battery monomer, and also improves the stability of the pressure relief component under the action of the internal pressure of the battery monomer.

[0036] In some embodiments of the first aspect of the present application, at least part of the main part is arranged in the through hole, along the thickness direction of the first wall part, the main part has a first surface away from the electrode assembly, the first wall part has a third surface 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 part.

[0037] In the above technical solution, by arranging the first surface of the main part away from the electrode assembly and the third surface of the first wall part away from the electrode assembly to be flush, the first wall part and the pressure relief component are connected to form the connecting part at the junction position of the first surface and the third surface.

[0038] In some embodiments of the first aspect of the present application, the main body part comprises a first body and a first protruding part, the first surface is a surface of the first body facing away from the electrode assembly along a thickness direction of the first wall part, and the first protruding part protrudes from the first surface; the battery monomer further comprises a protective piece connected to one end of the first protruding part away from the first surface and forming a gap with the weak part.

[0039] In the above technical solution, by protruding the first protruding part from the first surface of the first body facing away from the electrode assembly, and connecting the protective piece to one end of the first protruding part away from the first surface and forming a gap with the weak part, the protective piece can not only protect the weak part, but also provide more space for the pressure relief part to release the internal pressure of the battery monomer, so as to avoid the influence of the protective piece on the weak part releasing the internal pressure of the battery monomer, so that the battery monomer can be timely relieved, and the reliability of the battery monomer is further improved. By protruding the first protruding part from the first surface of the first body facing away from the electrode assembly, and connecting the protective piece to one end of the first protruding part away from the first surface, the first protruding part and the protective piece can not occupy the space inside the shell, which is conducive to improving the energy density of the battery monomer, and the protective piece can also reduce the risk of the external structure of the battery monomer damaging the weak part, thereby improving the reliability of the battery monomer.

[0040] In some embodiments of the first aspect of the present application, a first accommodating groove is arranged on a side of the first wall part facing away from the electrode assembly, the first accommodating groove is communicated with the through hole, and the main body part does not exceed the groove bottom surface of the first accommodating groove along a direction in which the electrode assembly points to the first wall part.

[0041] In the above technical solution, by making the main body part not exceed the groove bottom surface of the first accommodating groove, the space occupied by the pressure relief part outside the battery monomer is reduced, which is conducive to reducing the volume of the battery monomer and improving the energy density of the battery monomer. In addition, by making the main body part not exceed the groove bottom surface of the first accommodating groove, the risk of interference between the pressure relief part and the external equipment is reduced, thereby reducing the risk of external impact on the pressure relief part, and further improving the reliability of the battery monomer.

[0042] In some embodiments of the first aspect of the present application, the groove bottom surface of the first accommodating groove is flush with the surface of the main body part farthest away from the electrode assembly.

[0043] In the above technical solution, by making the groove bottom surface of the first accommodating groove flush with the surface of the main body part farthest away from the electrode assembly, the surface of the main body part and the first wall part away from the electrode assembly has a distance, thereby reducing the risk of the external structure damaging the weak part and improving the reliability of the battery monomer. In addition, by making the groove bottom surface of the first accommodating groove flush with the surface of the main body part farthest away from the electrode assembly, the external space occupied by the pressure relief part is reduced, which is conducive to reducing the volume of the battery monomer.

[0044] In some embodiments of the first aspect of the present application, along the thickness direction of the first wall portion, one side of the first wall portion is provided with a second accommodating groove, the second accommodating groove is in communication with the through hole, and the limiting portion is accommodated in the second accommodating groove, and along the thickness direction of the first wall portion, the limiting portion abuts against the groove bottom wall of the second accommodating groove.

[0045] In the above technical solution, the first wall portion is provided with the second accommodating groove on one side in the thickness direction thereof, and the limiting portion is accommodated in the second accommodating groove, which is beneficial to reducing the volume of the battery monomer.

[0046] In some embodiments of the first aspect of the present 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 accommodating groove is arranged on the fourth surface, and along the direction of the first wall portion pointing to the electrode assembly, the limiting portion does not exceed the fourth surface.

[0047] In the above technical solution, the first wall portion is provided with the second accommodating groove on the fourth surface closest to the electrode assembly in the thickness direction thereof, and after the limiting portion is accommodated in the second accommodating groove, the limiting portion does not exceed the fourth surface, so that the limiting portion does not occupy the internal space of the shell, which is beneficial to improving the energy density of the battery monomer. After the limiting portion is accommodated in the second accommodating groove, the limiting portion does not exceed the fourth surface, which also makes the distance between the limiting portion and the electrode assembly larger, thereby reducing the risk of damaging the electrode assembly when the first wall portion is connected with the pressure relief component.

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

[0049] In the above technical solution, by abutting the limiting portion against the outer side of the first wall portion, the pressure relief component is conveniently assembled on the first wall portion.

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

[0051] In the above technical solution, by making the weak portion not exceed the fourth surface of the first wall portion closest to the electrode assembly, the space occupied by the pressure relief component in the internal space of the shell is reduced or avoided, which is beneficial to improving the energy density of the battery monomer. By making the weak portion not exceed the fourth surface, the risk of interference between the weak portion and the electrode assembly is small, which is beneficial to improving the reliability of the battery monomer.

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

[0053] In the technical solution, the main body part does not exceed the surface of the limiting part away from the first wall part, which is beneficial to reduce the size of the battery monomer.

[0054] In some embodiments of the first aspect of the application, the limiting part and the first wall part are connected to form the connecting part, and the connecting part is located on the inner side of the outer circumferential surface of the limiting part.

[0055] In the technical solution, the connecting part is formed by connecting the limiting part and the first wall part, which is convenient for connection. The connecting part is located on the inner side of the outer circumferential surface of the limiting part, so that the pressure relief component can be affected by the internal pressure of the battery monomer on both sides of the connecting part along the radial direction of the through hole. This makes the force on both sides of the connecting part balanced, reduces the risk of failure of the connecting part due to unbalanced force, and improves the reliability and prolongs the service life of the battery monomer.

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

[0057] In the technical solution, d is greater than or equal to D / 5, so that the limiting portion has sufficient thickness to connect with the first wall portion, and the connecting portion formed by the connection of the limiting portion and the first wall portion has a large connecting area, which is beneficial to improve the connection stability of the pressure relief component and the first wall portion. In the case of connecting the first wall portion and the limiting portion by welding, d greater than or equal to D / 5 can reduce the risk of the limiting portion being welded through while ensuring a large depth of the molten pool, thereby improving the connection stability of the first wall portion and the limiting portion and the strength of the laminated area of the limiting portion and the first wall portion. d less than or equal to 5D can reduce the space occupied by the limiting portion. If the limiting portion is located on the inner side of the first wall portion, the space occupied by the limiting portion in the interior of the shell can be reduced, thereby improving the energy density of the battery monomer. If the limiting portion is located on the outer side of the first wall portion, the space occupied by the limiting portion in the exterior of the battery monomer can be reduced, which is beneficial to reduce the volume of the battery monomer. Therefore, D / 5≤d≤5D can not only improve the connection stability of the pressure relief component and the first wall portion, but also reduce the space occupied by the limiting portion. d is greater than or equal to D / 3, so that the limiting portion has sufficient thickness to connect with the first wall portion, and the connecting portion formed by the connection of the limiting portion and the first wall portion has a larger connecting area, which is beneficial to improve the connection stability of the pressure relief component and the first wall portion. In the case of connecting the first wall portion and the limiting portion by welding, d greater than or equal to D / 3 can reduce the risk of the limiting portion being welded through while ensuring a larger depth of the molten pool, thereby further improving the connection stability of the first wall portion and the limiting portion and the strength of the laminated area of the limiting portion and the first wall portion. d less than or equal to 2D can further reduce the space occupied by the limiting portion. If the limiting portion is located on the inner side of the first wall portion, the space occupied by the limiting portion in the interior of the shell can be further reduced, thereby improving the energy density of the battery monomer. If the limiting portion is located on the outer side of the first wall portion, the space occupied by the limiting portion in the exterior of the battery monomer can be further reduced, which is beneficial to reduce the volume of the battery monomer. Therefore, D / 3≤d≤2D can not only improve the connection stability of the pressure relief component and the first wall portion, but also further reduce the space occupied by the limiting portion.

[0058] In some embodiments of the first aspect of the present application, the shell comprises a shell body and an end cover, the shell body has an opening, and the end cover closes the opening. The end cover is the first wall portion.

[0059] In the technical solution, the end cover is the first wall portion. By installing the pressure relief component on the end cover, the end cover can be located on the top of the battery monomer, which can reduce the risk of electrolyte corroding the pressure relief component, improve the working stability of the pressure relief component, and reduce the infiltration of electrolyte into the pressure relief component, thereby improving the reliability of the battery monomer and prolonging the service life of the battery monomer.

[0060] In some embodiments of the first aspect of the present application, the shell comprises a shell body and an end cover, the shell body has an opening, and the end cover closes the opening. The shell comprises the first wall portion.

[0061] In the technical solution, the shell includes a first wall part, and the pressure relief component is arranged on the wall part of the shell, which is beneficial to improving the energy density of the battery monomer.

[0062] In some embodiments of the first aspect of the application, the shell includes a bottom wall and a side wall surrounding the bottom wall, one end of the side wall is connected to the bottom wall, and the other end of the side wall forms the opening; and the bottom wall is the first wall part.

[0063] In the technical solution, the bottom wall is the first wall part, and the pressure relief component is arranged on the bottom wall, which reduces the risk of damage to other structures inside the battery monomer caused by heat released by the pressure relief component, and reduces the risk of fire, explosion and other problems, thereby improving the reliability of the battery monomer.

[0064] In some embodiments of the first aspect of the application, the shell includes a bottom wall and a side wall surrounding the bottom wall, one end of the side wall is connected to the bottom wall, and the other end of the side wall forms the opening; and the side wall is the first wall part.

[0065] In the technical solution, the side wall includes the first wall part, and the pressure relief component is arranged on the side wall, which is beneficial to improving the energy density of the battery monomer.

[0066] In some embodiments of the first aspect of the application, the side wall includes a first side wall and a second side wall arranged adjacent to each other, the area of the outer surface of the first side wall is greater than the area of the outer surface of the second side wall, and the second side wall is the first wall part.

[0067] In the technical solution, the area of the outer surface of the first side wall is greater than the area of the outer surface of the second side wall, and the second side wall is the first wall part. By arranging the pressure relief component on the second side wall with a smaller outer surface area, the adjacent battery monomers do not interfere with the pressure relief of the pressure relief component when the plurality of battery monomers are stacked, which is beneficial to improving the reliability of the battery monomer and the reliability of the battery device including the plurality of battery monomers.

[0068] In the second aspect, the embodiments of the application provide a battery device including the battery monomer provided by any one of the embodiments of the first aspect.

[0069] In the technical solution, the battery monomer provided by the embodiments of the first aspect has good reliability, which improves the reliability of the battery device including the battery monomer.

[0070] In the third aspect, the embodiments of the application provide a power consumption device including the battery monomer provided by any one of the embodiments of the first aspect or the battery device provided by the embodiments of the second aspect.

[0071] In the technical solution, the single battery cell provided by the first aspect and the battery device provided by the second aspect both have good reliability, which is beneficial to improving the power supply reliability of the power consumption equipment powered by the battery cell or the battery device. BRIEF DESCRIPTION OF DRAWINGS

[0072] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0073] Figure 1 The structural schematic diagram of the vehicle provided by some embodiments of the present application;

[0074] Figure 2 The exploded view of the battery device provided by some embodiments of the present application;

[0075] Figure 3 The exploded view of the battery cell provided by some embodiments of the present application;

[0076] Figure 4 The isometric view of the battery cell provided by some embodiments of the present application;

[0077] Figure 5 The schematic diagram of the first wall part and the pressure relief component after being connected provided by some embodiments of the present application;

[0078] Figure 6 The Figure 5 The sectional view in the direction of P1-P1;

[0079] Figure 7 The view of the shell from another perspective provided by some embodiments of the present application;

[0080] Figure 8 The Figure 7 The sectional view in the direction of P2-P2;

[0081] Figure 9 The Figure 8 The enlarged view of A1;

[0082] Figure 10 The schematic diagram of the pressure relief component and the protection piece provided by some embodiments of the present application;

[0083] Figure 11 The partial sectional view of the pressure relief component provided by some embodiments of the present application;

[0084] Figure 12 The isometric view of the shell provided by some embodiments of the present application;

[0085] Figure 13 Schematic view of another perspective of the housing provided for some embodiments of the present application;

[0086] Figure 14 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 13 Schematic view of a section in the P3-P3 direction of the housing;

[0087] Figure 15 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 14 Schematic view of a section in the A2 direction of the housing;

[0088] Figure 16 Schematic view of the pressure relief member and the shield cooperating provided for some embodiments of the present application;

[0089] Figure 17 Schematic view of the pressure relief member provided for some embodiments of the present application;

[0090] Figure 18 Schematic view of another perspective of the housing provided for some embodiments of the present application;

[0091] Figure 19 Schematic view of another perspective of the housing provided for some embodiments of the present application;

[0092] Figure 20 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 19 Schematic view of a section in the P4-P4 direction of the housing;

[0093] Figure 21 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 20 Schematic view of a section in the A3 direction of the housing;

[0094] Figure 22 Schematic view of the pressure relief member and the shield cooperating provided for some embodiments of the present application.

[0095] Figure 23 Schematic view of the pressure relief member provided for some embodiments of the present application;

[0096] Figure 24 Schematic view of another perspective of the housing provided for some embodiments of the present application;

[0097] Figure 25 Schematic view of another perspective of the housing provided for some embodiments of the present application;

[0098] Figure 26 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 24 Schematic view of a section in the P5-P5 direction of the housing;

[0099] Figure 27 Schematic view of another perspective of the housing provided for some embodiments of the present application; Figure 26 Schematic view of a section in the A4 direction of the housing;

[0100] Figure 28A schematic view of the pressure relief member and the shield after being fitted together according to some embodiments of the present application.

[0101] Figure 29 A partial sectional view of the pressure relief member according to some embodiments of the present application.

[0102] Icon: 1000 - vehicle; 100 - battery device; 10 - case; 11 - first case; 12 - second case; 20 - battery cell; 21 - housing; 211 - shell; 2111 - opening; 2112 - side wall; 21121 - first side wall; 21122 - second side wall; 2113 - bottom wall; 212 - end cover; 213 - first wall portion; 2131 - through hole; 2132 - first receiving groove; 21321 - groove 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 collecting member; 25 - pressure relief member; 251 - connecting portion; 252 - main body portion; 2521 - weak portion; 2522 - first portion; 2523 - second portion; 25231 - second region; 25232 - third region; 2524 - first body; 25241 - first surface; 2525 - first protruding portion; 25251 - inner peripheral surface of the first protruding portion; 253 - limiting portion; 2531 - second body; 25311 - second surface; 2532 - second protruding portion; 25321 - inner peripheral surface of the second protruding portion; 254 - first recess; 2541 - first groove portion; 25411 - side wall surface of the first groove portion; 2542 - second groove portion; 25421 - side wall surface of the second groove portion; 255 - second recess; 26 - shield; 200 - controller; 300 - motor; X - thickness direction of the first wall portion. DETAILED DESCRIPTION

[0103] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0104] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the specification herein is for describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The articles 'a', 'an', and 'the' each followed by'some or more' or 'one or more' of an element are intended to include one or more articles of the described element and do not exclude other additional elements. The terms "comprises", "comprising", "includes", "including", "has", "having" and the like are inclusive and are used as equivalents of the term "consisting of".

[0105] Reference throughout this application to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of other embodiments.

[0106] In the description of the application, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection", "attaching" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0107] The term "and / or" in the application is only a description of the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the application generally represents that the front and rear associated objects have an "or" relationship.

[0108] In the embodiments of the application, the same reference signs represent the same parts, and for the sake of brevity, the detailed description of the same parts is omitted in different embodiments. It should be understood that the thickness, length and width of various components in the embodiments of the application shown in the drawings, and the overall thickness, length and width of the integrated device are only exemplary and should not constitute any limitation on the application.

[0109] "Multiple" appearing in the application means two or more (including two).

[0110] In the embodiments of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0111] The battery cell includes, but is not limited to, a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium-metal battery, a sodium-metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, and the like.

[0112] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During charging and discharging of the battery cell, active ions (e.g., lithium ions) are intercalated and deintercalated between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, and can serve to reduce the risk of short circuiting between the positive electrode and the negative electrode, while allowing the active ions to pass through.

[0113] In some embodiments, the positive electrode can be a positive electrode tab, which can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0114] By way of example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode active material is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0115] By way of example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, and the like can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, and the like) on a polymer material base material (e.g., a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, and the like).

[0116] By way of example, the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material of a battery cell can also be used. These positive electrode active materials can be used alone or in combination of two or more. Examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3Mn 1 / 3O2(also can be referred to as NCM 333 O2(also can be referred to as NCM 0.5 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 0.3 O2(also can be referred to as NCM 523 O2(also can be referred to as NCM 0.5 O2(also can be referred to as NCM 0.25 O2(also can be referred to as NCM 0.25 O2(also can be referred to as NCM 211 O2(also can be referred to as NCM 0.6 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 622 O2(also can be referred to as NCM 0.8 O2(also can be referred to as NCM 0.1 O2(also can be referred to as NCM 0.1 O2(also can be referred to as NCM 811 O2(also can be referred to as NCM 0.85 O2(also can be referred to as NCM 0.15 O2(also can be referred to as NCM 0.05 O2(also can be referred to as NCM

[0117] In some embodiments, the positive electrode can employ a foam metal. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, etc. When the foam metal is used as the positive electrode, the surface of the foam metal can not be provided with the positive electrode active material, or of course can be provided with the positive electrode active material. As an example, the foam metal can also be filled or / and deposited with a lithium source material, a potassium metal or a sodium metal, the lithium source material being a lithium metal and / or a lithium-rich material.

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

[0119] As an example, the negative electrode current collector can employ a metal foil, a foam metal or a composite current collector. For example, as the metal foil, an aluminum with a silver plating treatment on the surface, a stainless steel with a silver plating treatment on the surface, a stainless steel, a copper, an aluminum, a nickel, a carbon electrode, carbon, nickel or titanium, etc. can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, etc. The composite current collector can include a high polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a high polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0120] As an example, the negative electrode sheet can include the negative electrode current collector and the negative electrode active material provided on at least one surface of the negative electrode current collector.

[0121] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is provided on either one or both of the two surfaces of the negative electrode current collector.

[0122] As an example, the negative electrode active material can employ a negative electrode active material for a battery cell known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery cell can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0123] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0124] In some embodiments, the separator is a separator film. The separator film can be any porous structure separator film known in the art that has good chemical stability and mechanical stability.

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

[0126] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive and negative electrodes, and functions to transport ions and separate the positive and negative electrodes.

[0127] In some embodiments, the battery cell further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The electrolyte can be in a liquid state, a gel state, or a solid state. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0128] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethylsulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium boric oxalate, lithium difluorophosphoric oxalate, and lithium tetrafluorophosphoric oxalate.

[0129] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from ether solvents. The ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0130] In some embodiments, the gel-state electrolyte includes a polymer as a skeleton network of the electrolyte, and an ionic liquid-lithium salt.

[0131] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0132] As an example, the polymer solid-state electrolyte can be a polyether (polyethylene oxide), a polysiloxane, a polycarbonate, a polyacrylonitrile, a polyvinylidene fluoride, a polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, cellulose, or the like.

[0133] As an example, the inorganic solid-state electrolyte can include one or more of an oxide solid-state electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), a sulfide solid-state electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorous sulfide, argyrodite), amorphous sulfide), and a halide solid-state electrolyte, a nitride solid-state electrolyte, and a hydride solid-state electrolyte.

[0134] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

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

[0136] In some embodiments, the electrode assembly is in a stack structure.

[0137] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be alternately stacked.

[0138] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet is folded to form a plurality of folded segments that are stacked. One positive electrode sheet is clamped between adjacent folded segments.

[0139] As an example, the positive electrode sheet and the negative electrode sheet are both folded to form a plurality of folded segments that are stacked.

[0140] As an example, the separators can be provided in plurality, each provided between any adjacent positive electrode tab or negative electrode tab.

[0141] As an example, the separators can be provided in plurality, each provided between any adjacent positive electrode tab or negative electrode tab.

[0142] In some embodiments, the electrode assembly can have a shape of a cylinder, a flat, a polygonal prism, or the like.

[0143] In some embodiments, the electrode assembly can be provided with a tab, which can lead current out of the electrode assembly. The tab can include a positive electrode tab and a negative electrode tab.

[0144] In some embodiments, the battery cell can include a case. The case can be used to enclose components such as the electrode assembly and the electrolyte. The case can be a steel case, an aluminum case, a plastic case (e.g., polypropylene), a composite metal case (e.g., a copper-aluminum composite case), or an aluminum-plastic film, or the like.

[0145] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes, the prismatic battery cell including a square battery cell, a blade battery cell, a polygonal prism battery cell (e.g., a hexagonal prism battery cell), or the like.

[0146] A battery apparatus according to embodiments of the present application can include one or more battery cell assemblies to provide voltage and capacity. A battery cell assembly can include a plurality of battery cells connected in series, in parallel, or in a mixed connection through a busbar.

[0147] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells; as an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of battery cells into a single independent module.

[0148] As an example, the battery module can be formed by bundling a plurality of battery cells with a cable tie.

[0149] In some embodiments, the battery apparatus can be a battery pack, which can include a case and one or more battery cell assemblies, the battery cell assemblies housed in the case.

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

[0151] As an example, the battery cell assembly can also be housed in the box by directly fixing a plurality of battery cells to the box.

[0152] As an example, the box can include a first box and a second box. The first box and the second box are fastened so that an enclosed space is formed inside the box to accommodate the battery cell assembly. The enclosed here means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0153] As an example, the box can include a top cover, a frame and a bottom plate. The top cover and the bottom plate are connected with the frame, so that an enclosed space is formed inside the box to accommodate the battery cell assembly.

[0154] As an example, the box can be part of the chassis structure of the vehicle. For example, the top cover of the box can be at least part of the floor of the vehicle, or the frame of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0155] In some embodiments, the battery device refers to an energy storage device, which includes a box, at least one side of which is provided with a door. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0156] In order to improve the reliability of the battery cell, the shell of the battery cell is provided with a pressure relief component, the shell is provided with a through hole, the pressure relief component covers the through hole, and the shell and the pressure relief component are connected to form a connecting portion, the connecting portion extends to the outer peripheral surface of the pressure relief component, which causes the pressure relief component to be subjected to the pressure inside the battery cell only on the inner side of the connecting portion (the side close to the axis of the through hole), so that the force on both sides of the connecting portion is unbalanced, and the side of the connecting portion is repeatedly subjected to the pressure inside the battery cell, which is easy to cause the connecting portion to fail, thereby reducing the reliability of the battery cell.

[0157] In view of this, in order to improve the reliability of the battery cell, the battery cell provided by the embodiments of the present application includes a shell, an electrode assembly and a pressure relief component. The shell has a first wall portion provided with a through hole. The electrode assembly is accommodated in the shell. The pressure relief component is connected with 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 is connected with the main body portion and surrounds at least part of the outer periphery of the main body portion. The main body portion is arranged opposite to the through hole. The main body portion has a weak portion configured to be able to be damaged to release the pressure inside the battery cell. In the thickness direction of the first wall portion, the limiting portion abuts against the first wall portion. In the projection plane perpendicular to the thickness direction of the first wall portion, at least part of the orthographic projection of the limiting portion is located outside the orthographic projection of the connecting portion.

[0158] The limiting portion abuts against the first wall portion in the thickness direction of the first wall portion, so that the first wall portion and the pressure relief component form a limit, facilitating installation of the pressure relief component on the first wall portion, and improving the stress capacity of the abutting region of the pressure relief component and the first wall portion.

[0159] The at least part of the orthographic projection of the limiting portion is located outside the orthographic projection of the connecting portion 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, so that the pressure relief component can be stressed on both sides of the connecting portion along the radial direction of the through hole, such as the pressure relief component being stressed by the internal pressure of the battery monomer on both sides of the connecting portion along the radial direction of the through hole or the pressure relief component being stressed by the external load of the battery monomer on both sides of the connecting portion along the radial direction of the through hole, so that the stress on both sides of the connecting portion is balanced, reducing the risk of failure of the connecting portion due to unbalanced stress in the radial direction of the through hole, thereby improving the reliability of the battery monomer and prolonging the service life of the battery monomer.

[0160] The technical solutions described in the embodiments of the present application are applicable to various electric devices using battery monomers and battery devices, such as mobile phones, portable devices, notebook computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, etc., such as spacecraft including airplanes, rockets, space shuttles and spacecraft, etc.

[0161] The following embodiments are described for convenience of illustration, taking the electric device as a vehicle as an example.

[0162] Please refer to Figure 1 , Figure 1 The structural schematic diagram of the vehicle 1000 provided by some embodiments of the present application is shown. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, head or tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as the operating power supply of the vehicle 1000.

[0163] The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the working power demand of the vehicle 1000 during starting, navigation and driving.

[0164] In some embodiments of the present application, the battery device 100 can not only be used as the operating power supply of the vehicle 1000, but also be used as the driving power supply of 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 , Figure 2An exploded view of the battery device 100 provided for some embodiments of the present application can include a box 10 and a battery cell 20, the box 10 being used to accommodate the battery cell 20.

[0166] The box 10 has an enclosed space formed inside for accommodating the battery cell 20. The box 10 can adopt various structures. In some embodiments, the box 10 can include a first box 11 and a second box 12, the first box 11 and the second box 12 being buckled to each other. The first box 11 and the second box 12 can be various shapes, such as a cuboid, a cylinder, etc. The first box 11 can be a hollow structure with one side open, and the second box 12 can also be a hollow structure with one side open, the open side of the second box 12 being buckled to the open side of the first box 11, thus forming the box 10 with the enclosed space. Alternatively, the first box 11 can be a hollow structure with one side open, and the second box 12 can be a plate-shaped structure, the second box 12 being buckled to the open side of the first box 11, thus forming the box 10 with the enclosed space.

[0167] In the battery device 100, the battery cell 20 can be one or multiple. If the battery cell 20 is multiple, the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection, the mixed connection referring to that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection to form a battery module, and the multiple battery modules can be connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the box 10. Alternatively, all the battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and the whole formed by the battery cells 20 is accommodated in the box 10.

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

[0169] Please refer to Figure 3 and Figure 4 , Figure 3 An exploded view of the battery cell 20 provided for some embodiments of the present application, Figure 4 An isometric view of the battery cell 20 provided for some embodiments of the present application, the battery cell 20 can include a shell 21 and an electrode assembly 22, the electrode assembly 22 being accommodated in the shell 21.

[0170] In some embodiments, the shell 21 can include a shell body 211 and an end cover 212, the shell body 211 having an opening 2111, and the end cover 212 closing the opening 2111 of the shell body 211. Here, closing refers to covering or closing, which can be sealing or non-sealing.

[0171] The shell 211 is a component for accommodating the electrode assembly 22. The shell 211 can be a hollow structure with an opening 2111 formed at one end. The shell 211 can be a hollow structure with openings 2111 formed at opposite ends. The shell 211 can have various shapes, such as a cylindrical shape, a cuboid shape, etc. The shell 211 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The electrode assembly 22 can be partially located in the shell 211 or entirely located in the shell 211.

[0172] The end cap 212 cooperates with the shell 211 to define a receiving space for accommodating the electrode assembly 22 and other components. The end cap 212 can be connected to the shell 211 by welding, crimping, etc., to close the opening 2111 of the shell 211. The end cap 212 can have a shape that matches the shape of the shell 211, such as a rectangular plate structure that matches the cuboid structure of the shell 211, or a circular plate structure that matches the cylindrical structure of the shell 211. The end cap 212 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The end cap 212 and the shell 211 can be made of the same material or different materials.

[0173] In embodiments where the shell 211 has an opening 2111 at one end, one end cap 212 can be provided. In embodiments where the shell 211 has openings 2111 at opposite ends, two end caps 212 can be provided, which close the two openings 2111 of the shell 211, respectively. The two end caps 212 cooperates with the shell 211 to define the receiving space.

[0174] In some embodiments, the battery cell 20 can further include an electrode terminal 23 provided on the housing 21. The electrode terminal 23 is electrically connected to the tab of the electrode assembly 22 to input or output the electric energy of the battery cell 20. The electrode terminal 23 can be provided on the shell 211 of the housing 21 or on the end cap 212 of the housing 21. The electrode terminal 23 can be directly connected to the tab, such as by welding. The electrode terminal 23 can be indirectly connected to the tab, such as by a current collecting member 24. The current collecting member 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0175] As an example, as shown in FIG. 1, the electrode terminal 23 is provided on the end cap 212 of the housing 21. The electrode terminal 23 is directly connected to the tab of the electrode assembly 22 by welding. Figure 3As shown, the shell 211 forms an opening 2111 at one end, and the end cover 212 in the shell 21 is one, and one end cover 212 closes one opening 2111 of the shell 211. Two electrode terminals 23 are arranged on the end cover 212, and the two electrode terminals 23 are respectively a positive electrode terminal and a negative electrode terminal. The electrode assembly 22 forms a positive electrode tab and a negative electrode tab at one end facing the end cover 212, and 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] Please refer to Figure 5 、 Figure 6 The battery monomer 20 provided by the embodiment of the application includes a shell 21, an electrode assembly 22, and a pressure relief component 25. The shell 21 has a first wall portion 213 provided with a through hole 2131. The electrode assembly 22 is accommodated in the shell 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. The limiting portion 253 is connected to the main body portion 252 and surrounds at least part of the outer periphery of the main body portion 252. The main body portion 252 is arranged opposite to the through hole 2131. The main body portion 252 has a weak portion 2521 configured to be able to be damaged to release the pressure inside the battery monomer 20. In the thickness direction X of the first wall portion, the limiting portion 253 abuts against the first wall portion 213. In the projection plane perpendicular to the thickness direction X of the first wall portion, at least part 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 is any wall portion of the shell 21. For example, the first wall portion 213 is a side wall 2112 or a bottom wall 2113 of the shell 211, or the first wall portion 213 can be the end cover 212.

[0178] The through hole 2131 penetrates through both sides in the thickness direction X of the first wall portion, and the through hole 2131 can communicate the inside and the outside of the shell 21. The axial direction of the through hole 2131 can be parallel to the thickness direction X of the first wall portion, or can be arranged at an angle to the thickness direction X of the first wall portion. The shape of the through hole 2131 can be various, such as a circular shape, an elliptical shape, a square shape, etc.

[0179] The pressure relief component 25 is connected to the first wall portion 213 and covers the through hole 2131 to separate the inside and the outside of the shell 21. The pressure relief component 25 can be damaged, so that the through hole 2131 communicates the inside and the outside of the shell 21.

[0180] The projection of the main body portion 252 is located within the through hole 2131 when viewed in the thickness direction X of the first wall portion. 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, that is, the limiting portion 253 surrounds the entire outer periphery of the main body portion 252 by 360°. Alternatively, the limiting portion 253 can surround part of the outer periphery of the main body portion 252 in the circumferential direction, that is, the limiting portion 253 surrounds part of the outer periphery of the main body portion 252 by less than 360°.

[0181] The main body portion 252 and the limiting portion 253 can be integrally formed, for example, by stamping, casting, or the like.

[0182] Alternatively, the main body portion 252 and the limiting portion 253 can be separately provided and connected to form an integral structure. The main body portion 252 and the limiting portion 253 can be connected by welding, adhesion, or the like.

[0183] The weak portion 2521 is the weakest region of the pressure relief member 25. The weak portion 2521 is located in the main body portion 252. Since the main body portion 252 is arranged opposite the through hole 2131, the main body portion 252 can directly receive the pressure inside the battery cell 20. Therefore, when the pressure or temperature inside the battery cell 20 reaches a threshold value, the weak portion 2521 is broken by the pressure of the battery cell 20, for example, the weak portion 2521 is torn, so that the pressure relief member 25 opens the through hole 2131 to release the pressure inside the battery cell 20.

[0184] The weak portion 2521 can be formed in various ways. For example, the weak portion 2521 can be formed by providing a score groove in the main body portion 252 of the pressure relief member 25, and the groove bottom wall 2113 of the score groove forms the weak portion 2521. Alternatively, the weak portion 2521 can be formed by providing a material with relatively weak strength in the main body portion 252.

[0185] At least part of the limiting portion 253 overlaps at least part of the first wall portion 213 when viewed in the thickness direction X of the first wall portion. The limiting portion 253 can be located on the side of the first wall portion 213 facing the electrode assembly 22, or on the side of the first wall portion 213 facing away from the electrode assembly 22. Figure 9 Fig. 2 shows a case where the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, Figure 27 Figure 28 Fig. 3 shows a case where the limiting portion 253 is located on the side of the first wall portion 213 facing away from the electrode assembly 22.

[0186] ​The connection between the pressure relief component 25 and the first wall portion 213 can be achieved in various ways, such as by adhesive bonding, welding, etc. In an embodiment where the pressure relief component 25 and the first wall portion 213 are welded together, the connection portion 251 is a weld bead. The connection portion 251 can be a closed annular structure along the circumferential direction of the through hole 2131, or an open structure extending along the circumferential direction of 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 projection of the connection portion 251 refers to the side of the connection portion 251 facing away from the axis of the through hole 2131 in the radial direction of the through hole 2131; and the inner side of the projection of the connection portion 251 refers to the side of the connection portion 251 facing 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 part of the projection of the limiting portion 253 is located on the outer side of the projection of the connection portion 251, so that the edge of the limiting portion 253 facing away from the main body portion 252 has a distance from the connection portion 251 in the radial direction of the through hole 2131. At least part of the limiting portion 253 and at least part of the main body portion 252 are located on the two sides of the connection portion 251 in the radial direction of the through hole 2131, respectively. The part of the limiting portion 253 located on the side of the connection portion 251 facing away from the main body portion 252 and the part of the main body portion 252 located on the side of the connection portion 251 facing away from the limiting portion 253 can be directly or indirectly subjected to the pressure inside the battery cell 20.

[0189] By abutting the limiting portion 253 against the first wall portion 213 in the thickness direction X of the first wall portion, the first wall portion 213 and the pressure relief component 25 form a limit, facilitating the installation of the pressure relief component 25 on the first wall portion 213, and improving the stress capacity of the abutting region of the pressure relief component 25 and the first wall portion 213. By locating at least part of the projection of the limiting portion 253 on the outer side of the projection of the connection portion 251 formed by the pressure relief component 25 and the first wall portion 213 in the projection plane perpendicular to the thickness direction X of the first wall portion, the pressure relief component 25 can be subjected to stress on both sides of the connection portion 251 in the radial direction of the through hole 2131, such as being subjected to the pressure inside the battery cell 20 on both sides of the connection portion 251 in the radial direction of the through hole 2131 or being subjected to the load outside the battery cell 20 on both sides of the connection portion 251 in the radial direction of the through hole 2131, so that the stress on both sides of the connection portion 251 is balanced, reducing the risk of failure of the connection portion 251 due to unbalanced stress in the radial direction of the through hole 2131, thereby improving the reliability of the battery cell 20 and prolonging the service life of the battery cell 20.

[0190] As shown in FIG. 2, the main body portion 252 and the first wall portion 213 are connected to form the connection portion 251. Figures 5-9 As shown in FIG. 2, the main body portion 252 and the first wall portion 213 are connected to form the connection portion 251.

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

[0192] In the case where the main body 252 and the first wall 213 are connected to form the connection part 251, the connection part 251 can also be formed at the laminated area between the first wall 213 and the limiting part 253, and the limiting part 253 and the first wall 213 can form at least two connection parts 251.

[0193] In some embodiments, the connection part 251 formed by the connection between the main body 252 and the first wall 213 can be at least partially located inside the through hole 2131. As shown in Figure 5 Figure 6 The pressure relief part 25 is in a plate structure, and the pressure relief part 25 is located on one side of the thickness direction X of the first wall. The main body 252 and the first wall 213 are connected, the connection part 251 is located inside the through hole 2131, and the connection part 251 connects the hole wall surface of the through hole 2131 and the surface of the main body 252 facing the through hole 2131.

[0194] In other embodiments, the connection part 251 formed by the connection between the main body 252 and the first wall 213 can be at least partially located outside the through hole 2131. For example, as shown in Figure 9 The main body 252 is inserted into the through hole 2131, and the part of the main body 252 inserted into the through hole 2131 is connected to the first wall 213 to form the connection part 251, and at least part of the connection part 251 is located inside the through hole 2131.

[0195] The connection between the main body 252 and the first wall 213 forms the connection part 251, so that the connection between the pressure relief part 25 and the first wall 213 is more stable. The connection between the main body 252 and the first wall 213 forms the connection part 251, so that the orthographic projection of the limiting part 253 in the projection plane perpendicular to the thickness direction X of the first wall is located in the area outside the connection part 251, thereby increasing the stress area of the pressure relief part 25 outside the connection part 251, thereby reducing the stress area difference between the inside and outside of the connection part 251 of the pressure relief part 25, further reducing the stress difference between the inside and outside of the connection part 251 of the pressure relief part 25, so that the stress on both sides of the pressure relief part 25 at the connection part 251 tends to be balanced, further reducing the risk of failure of the connection part 251 due to unbalanced stress on both sides, thereby improving the reliability of the battery monomer 20 and prolonging the service life of the battery monomer 20.

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

[0197] In the embodiment in which the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, as shown in Figure 9 The first portion 2522 is inserted into the through hole 2131 from the limiting portion 253 in the direction in which the electrode assembly 22 points to the first wall portion 213.

[0198] In the embodiment in which the limiting portion 253 is located on the side of the first wall portion 213 facing the electrode assembly 22, as shown in Figure 26 The first portion 2522 is inserted into the through hole 2131 from the limiting portion 253 in the direction in which the electrode assembly 22 points to the first wall portion 213.

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

[0200] The first portion 2522 can be a cylindrical structure closed in the circumferential direction of the through hole 2131. Of course, the first portion 2522 can also be other structures.

[0201] The second portion 2523 can be a plate structure, or a structure formed by bending a plate material.

[0202] The main body 252 can be an integrally formed structure, that is, the first portion 2522 and the second portion 2523 are integrally formed, for example, the main body 252 can be formed by an integrally forming mode such as stamping, casting, bending, etc.

[0203] The first portion 2522 and the second portion 2523 can also be separately arranged and connected, and the first portion 2522 and the second portion 2523 can be connected by welding, bonding, etc.

[0204] The first portion 2522 extends into the through hole 2131, and the first portion 2522 can be positioned and matched with the through hole 2131, facilitating the connection between the pressure relief component 25 and the first wall portion 213. After the first portion 2522 extends into the through hole 2131, the first portion 2522 is closer to the first wall portion 213, and the first portion 2522 and the first wall portion 213 are connected to form the connecting portion 251, so that the connection between the pressure relief component 25 and the first wall portion 213 is less difficult. The limiting portion 253 and the second portion 2523 are respectively connected to two ends of the first portion 2522, and the weak portion 2521 is arranged on the second portion 2523. The limiting portion 253 and the second portion 2523 form a buffer zone through the first portion 2522, so as to reduce the influence of stress on the second portion 2523 on the connecting portion 251, further reduce the risk of the connecting portion 251 caused by unbalanced stress on both sides, improve the reliability of the battery monomer 20, and prolong the service life of the battery monomer 20.

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

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

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

[0208] Exemplarily, 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 portion 2522 is connected with the first wall portion 213, by E≥D / 5, the first portion 2522 has sufficient thickness to be connected with the first wall portion 213, which is conducive to the connection portion 251 having sufficient connection area, improving the connection stability of the first portion 2522 and the first wall portion 213, thereby improving the reliability of the battery monomer 20. In the case of realizing the connection of the first wall portion 213 and the first portion 2522 by welding, E≥D / 5 can reduce the risk of the first portion 2522 being welded through while ensuring a larger depth of the molten pool, thereby improving the connection stability of the first wall portion 213 and the first portion 2522; by E≤5D, the thickness of the first portion 2522 is controlled within a reasonable range, reducing the area of the first portion 2522 occupying the through hole 2131, reducing the risk of the first portion 2522 affecting the pressure relief of the inside of the battery monomer 20 from the through hole 2131, and improving the reliability of the battery monomer 20. Therefore, by D / 5≤E≤5D, both the connection stability of the pressure relief component 25 and the first wall portion 213 can be better, and the influence of the first portion 2522 on the pressure relief of the through hole 2131 can be reduced.

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

[0211] Exemplarily, 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 E≥2D / 3, the connection portion 251 has a larger connection area, further improving the connection stability of the first portion 2522 and the first wall portion 213, thereby further improving the reliability of the battery monomer 20; by E≤3D, the thickness of the first portion 2522 is controlled within a smaller range, further reducing the area of the first portion 2522 occupying the through hole 2131, thereby further reducing the risk of the first portion 2522 affecting the pressure relief of the inside of the battery monomer 20 from the through hole 2131, and improving the reliability of the battery monomer 20. Therefore, by 2D / 3≤E≤3D, both the connection stability of the pressure relief component 25 and the first wall portion 213 can be better, and the influence of the first portion 2522 on the pressure relief of the through hole 2131 can be further reduced.

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

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

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

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

[0217] By having the first distance K between the connecting portion 251 and the surface of the first portion 2522 away from the hole wall surface of the through hole 2131 in the radial direction of the through hole 2131, the connecting portion 251 does not extend to the surface of the first portion 2522 away from the hole wall surface in the radial direction of the through hole 2131, reducing the influence of the connecting portion 251 on the strength of the first portion 2522, especially in the case where the first wall portion 213 and the pressure relief component 25 are welded to form the connecting portion 251. By having the first distance between the connecting portion 251 and the surface of the first portion 2522 away from the hole wall surface of the through hole 2131 in the radial direction of the through hole 2131, the first portion 2522 is not welded through, which can make the connection between the first wall portion 213 and the pressure relief component 25 more stable, and the strength of the overall structure formed by the pressure relief component 25 and the first wall portion 213 better. By K≥d / 10, the first portion 2522 still has good strength after being connected to the first wall portion 213, which is conducive to improving the ability of the pressure relief component 25 to resist external forces. By K≤4d, it is conducive to controlling the thickness of the first portion 2522 within a reasonable range, reducing the area occupied by the first portion 2522 in the through hole 2131, reducing the risk of the first portion 2522 affecting the pressure relief from the through hole 2131 inside the battery monomer 20, and improving the reliability of the battery monomer 20. Therefore, d / 10≤K≤4d, which not only makes the first portion 2522 still have good strength after being connected to the first wall portion 213, but also reduces the area occupied by the first portion 2522 in the through hole 2131, reduces the risk of the first portion 2522 affecting the pressure relief from the through hole 2131 inside the battery monomer 20, and improves the reliability of the battery monomer 20.

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

[0219] Exemplarily, 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 d / 5≤K≤3d / 2, not only the first part 2522 has better strength after being connected with the first wall part 213, but also the area of the first part 2522 occupying the through hole 2131 is further reduced, thereby further reducing the risk of the first part 2522 affecting the pressure relief of the battery monomer 20 from the through hole 2131, and improving the reliability of the battery monomer 20.

[0221] As shown in some embodiments, along the thickness direction X of the first wall part, the connecting part 251 extends from the surface of the first wall part 213 away from the limiting part 253 to the limiting part 253. Figure 9

[0222] In the embodiment in which the limiting part 253 is arranged on the side of the first wall part 213 away from the electrode assembly 22, the connecting part 251 extends from the surface of the first wall part 213 facing the electrode assembly 22 to the direction close to the limiting part 253.

[0223] In the embodiment in which the limiting part 253 is arranged on the side of the first wall part 213 facing the electrode assembly 22, the connecting part 251 extends from the surface of the first wall part 213 away from the electrode assembly 22 to the direction close to the limiting part 253.

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

[0225] In the embodiment in which the main body part 252 includes the first part 2522 and the 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 part 213 away from the limiting part 253 to the limiting part 253, which is conducive to the distance between the connecting part 251 and the second part 2523 in the thickness direction X of the first wall part, thereby reducing the damage to the weak part 2521 arranged on the second part 2523 during the process of forming the connecting part 251.

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

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

[0228] Exemplarily, 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] By the second distance H existing between the connecting portion 251 and the surface of the limiting portion 253 away from the first wall portion 213, the connecting portion 251 does not extend to the surface of the limiting portion 253 away from the first wall portion 213, reducing the influence of the connecting portion 251 on the strength of the limiting portion 253. Especially in the case that the first wall portion 213 and the pressure relief component 25 are welded to form the connecting portion 251, the second distance H existing between the connecting portion 251 and the surface of the limiting portion 253 away from the first wall portion 213 means that the limiting portion 253 is not welded through, which can make the connection between the first wall portion 213 and the pressure relief component 25 more stable, and the strength of the overall structure formed by the pressure relief component 25 and the first wall portion 213 better. By H≥d / 10, the limiting portion 253 still has good strength after the pressure relief component 25 is connected with the first wall portion 213, which is conducive to improving the ability of the pressure relief component 25 to resist external force. By H≤2d, the distance between the surface of the limiting portion 253 away from the first wall portion 213 and the connecting portion 251 is not too large, which avoids the size of the connecting portion 251 being too small, thereby reducing the connection stability of the pressure relief component 25 and the first wall portion 213, and improving the reliability of the battery monomer 20. Therefore, d / 10≤H≤2d makes the limiting portion 253 still have good strength after the pressure relief component 25 is connected with the first wall portion 213, and also enables the connecting portion 251 to have sufficient connection area, thereby improving the connection stability of the first wall portion 213 and the pressure relief component 25, and further improving the reliability of the battery monomer 20.

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

[0231] Exemplarily, 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 H≥d / 5, the limiting portion 253 has better strength after being connected with the first wall portion 213, which is beneficial to further improve the ability of the pressure relief component 25 to resist external force. By H≤d, the distance between the limiting portion 253 and the connecting portion 251 is not too large, which avoids the situation that the size of the connecting portion 251 is small, and the connection stability of the pressure relief component 25 and the first wall portion 213 is low, which is beneficial to improve the reliability of the battery monomer 20. Therefore, d / 5≤H≤d, which makes the limiting portion 253 have better strength after being connected with the first wall portion 213, and the connecting portion 251 has sufficient connection area, which improves the connection stability of the first wall portion 213 and the pressure relief component 25, and further improves the reliability of the battery monomer 20.

[0233] As shown in FIG. 13, in some embodiments, the main body portion 252 is at least partially disposed in the through hole 2131. Figure 9

[0234] The main body portion 252 can be partially located in the through hole 2131, or can be entirely located in the through hole 2131. The main body portion 252 extends from the limiting portion 253 to the through hole 2131.

[0235] In the embodiment in which 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 to the through hole 2131 in the direction in which the electrode assembly 22 points to the first wall portion 213.

[0236] In the embodiment in which 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 to the through hole 2131 in the direction in which the first wall portion 213 points to the electrode assembly 22.

[0237] In the embodiment in which the main body portion 252 includes the first portion 2522 and the second portion 2523, along the thickness direction X of the first wall portion, the first portion 2522 can be entirely located in the through hole 2131, or can be partially located in the through hole 2131, and the second portion 2523 can be entirely located in the through hole 2131, or can be partially located in the through hole 2131. As shown in FIG. 14, along the thickness direction X of the first wall portion, the first portion 2522 is entirely located in the through hole 2131, and a part of the second portion 2523 is located in the through hole 2131. Figure 9

[0238] Along the thickness direction X of the first wall portion, the end of the main body portion 252 away from the limiting portion 253 can extend out of the through hole 2131, or can be located in the through hole 2131. As shown in FIG. 15, along the thickness direction X of the first wall portion, the end of the main body portion 252 away from the limiting portion 253 extends out of the through hole 2131. As shown in FIG. 16, Figure 9 Figure 21 , Figure 22 ​​​As shown, along the thickness direction X of the first wall portion, the end of the main body portion 252 away from the limiting portion 253 does not extend through the 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] like Figures 9-11 As shown, 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 can be entirely located in the main body 252. Figures 9-11 (As shown). The first groove 254 may be partially located in the main body 252, and another part of the first groove 254 may be located in the limiting part 253 (as shown). Figures 26-28 (As shown)

[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 material of the protection piece 26 includes, but is not limited to, polyethylene, polypropylene, and other composite materials.

[0247] The pressure relief component 25 is provided with a first groove 254 on one side along the thickness direction X of the first wall portion. The weakened portion 2521 is arranged on the groove bottom wall 2113 of the first groove 254. The weakened portion 2521 is away from the side on which the opening of the first groove 254 faces. The distance between the weakened portion 2521 and the opening of the first groove 254 is increased. The risk of the weakened portion 2521 being damaged due to the structural contact with the side of the opening of the first groove 254 is reduced. The reliability of the battery monomer 20 is improved. The protection piece 26 is arranged on the side of the groove bottom wall 2113 of the first groove 254 away from the electrode assembly 22. The arrangement of the protection piece 26 is facilitated. The protection piece 26 is spaced apart from the groove bottom wall 2113 of the first groove 254 along the thickness direction X of the first wall portion. The protection piece 26 can protect the weakened portion 2521. The space for the pressure relief component 25 to release the internal pressure of the battery monomer 20 is provided. The protection piece 26 does not affect the weakened portion 2521 to release the internal pressure of the battery monomer 20. The battery monomer 20 can be timely relieved of pressure. The reliability of the battery monomer 20 is improved.

[0248] As shown in Figure 10 , Figure 11 In some embodiments, the main body portion 252 includes a first body 2524 and a first protruding portion 2525. The first body 2524 has a first surface 25241 along the thickness direction X of the first wall portion. The first protruding portion 2525 is protruded from the first surface 25241. The first surface 25241 is provided with a first groove portion 2541. The first groove 254 includes the first groove portion 2541. The weakened portion 2521 is arranged on the groove bottom wall 2113 of the first groove portion 2541. The protection piece 26 is connected to the end of the first protruding portion 2525 away from the first surface 25241.

[0249] The first surface 25241 can be the surface of the side of the first body 2524 away from the electrode assembly 22. The first protruding portion 2525 is protruded from the first surface 25241. The surface of the first protruding portion 2525 away from the first surface 25241 can be the surface of the pressure relief component 25 farthest away from the electrode assembly 22 along the thickness direction X of the first wall portion.

[0250] The first protruding portion 2525 can be a protruding block protruded from the first surface 25241. The first protruding portion 2525 can also be a closed loop structure protruded from the first surface 25241 and closed along the circumference of the through hole 2131.

[0251] The first surface 25241 is provided with a first groove portion 2541, and the weakened portion 2521 is arranged on the groove bottom wall 2113 of the first groove portion 2541. The protector 26 is connected to one end of the first protruding portion 2525 away from the first surface 25241, so that the gap between the protector 26 and the weakened portion 2521 is larger along the thickness direction X of the first wall portion. The protector 26 can not only protect the weakened portion 2521, but also provide more space for the pressure relief component 25 to release the internal pressure of the battery monomer 20, so as to avoid the influence of the protector 26 on the weakened portion 2521 to release the internal pressure of the battery monomer 20, so that the battery monomer 20 can be timely relieved, and the reliability of the battery monomer 20 is further improved.

[0252] As shown in Figures 12-17 The first protruding portion 2525 is arranged around the outer periphery of the slot of the first groove portion 2541. The first protruding portion 2525 and the first surface 25241 form a second groove portion 2542. The first groove portion 2541 is arranged on the groove bottom wall 2113 of the second groove portion 2542. The first groove 254 includes the second groove portion 2542.

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

[0254] The first protruding portion 2525 is arranged around the outer periphery of the slot of the first groove portion 2541. The surface of the first protruding portion 2525 away from the first surface 25241 is an annular surface arranged around the outer periphery of the axis of the through hole 2131, which can increase the connection area of the protector 26 and the first protruding portion 2525, and improve the stability of the connection between the protector 26 and the first protruding portion 2525. The first protruding portion 2525 and the first surface 25241 form a second groove portion 2542. The first groove 254 includes the second groove portion 2542. The first groove portion 2541 and the second groove portion 2542 jointly form a stepped first groove 254, which is beneficial to 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 protruding portion 2525 is arranged around the outer periphery of the slot of the first groove portion 2541. The inner peripheral surface 25251 of the first protruding portion is flush with the side wall surface 25411 of the first groove portion.

[0256] The inner circumferential surface 25251 of the first protruding portion refers to a surface of the first protruding portion 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 protruding portion is flush with the side wall surface 25411 of the first groove portion, and can also be understood as the inner circumferential surface 25251 of the first protruding portion being coplanar with the side wall surface 25411 of the first groove portion.

[0257] In Figure 9 , Figure 10 In the embodiments, the first wall portion 213 and the main body portion 252 are connected to form the connecting portion 251. Of course, the first wall portion 213 and the limiting portion 253 can also be connected to form the connecting portion 251. The inner circumferential surface 25251 of the first protruding portion is flush with the side wall surface 25411 of the first groove portion, and the first surface 25241 protrudes from the outer circumferential surface of the first protruding portion 2525.

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

[0259] As Figure 29 shown, in other embodiments, the limiting portion 253 includes a second body 2531 and a second protruding portion 2532. The main body portion 252 has a first surface 25241, the first surface 25241 is provided with a first groove portion 2541, the first recess 254 includes the first groove portion 2541, and the weak portion 2521 is arranged on the groove bottom wall 2113 of the first groove portion 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 protruding portion 2532 protrudes from the second surface 25311. The protective member 26 is connected to one end of the second protruding portion 2532 away from the second surface 25311.

[0260] The first surface 25241 can be a surface of the main body portion 252 away from the electrode assembly 22, and the first surface 25241 can also be a surface of the main body portion 252 farthest away from the electrode assembly 22.

[0261] The second surface 25311 can be a surface of the second body 2531 away from the first wall portion 213. In embodiments in which 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 a surface of the second body 2531 away from the electrode assembly 22, and the second protruding portion 2532 protrudes from the second surface 25311. Therefore, along the thickness direction X of the first wall portion, the surface of the second protruding portion 2532 away from the first surface 25241 can be a surface of the pressure relief component 25 farthest away from the electrode assembly 22.

[0262] The second protruding portion 2532 can be a bump protruding from the first surface 25241. The second protruding portion 2532 can also be a closed loop structure protruding from the first surface 25241 and along the circumference of the through hole 2131.

[0263] The outer circumferential surface of the second protruding portion 2532 can be flush with the outer circumferential surface of the second body 2531, and the second surface 25311 protrudes from the inner circumferential surface of the second protruding portion 2532. Then, the first surface 25241 and the second surface 25311 are connected at the portion of the first surface 25241 and the second surface 25311 protruding from the inner circumferential surface 25321 of the second protruding portion. Figure 27 And Figure 28 In the embodiments of the first wall portion 213, the portion of the second body 2531 that does not overlap with the second protruding portion 2532 is connected (welded) to the first wall portion 213 to form a connecting portion 251.

[0264] The end of the second protruding portion 2532 connected to the limiting portion 253 away from the second surface 25311 is connected to the first surface 25241 of the main body portion 252, and the first surface 25241 is coplanar with and connected to the second surface 25311. Thus, the gap between the protective member 26 and the weak portion 2521 is larger in the thickness direction X of the first wall portion. The protective member 26 not only protects the weak portion 2521, but also provides more space for the pressure relief member 25 to release the internal pressure of the battery monomer 20, so that the protective member 26 does not affect the weak portion 2521 to release the internal pressure of the battery monomer 20, so that the battery monomer 20 can be timely relieved, and the reliability of the battery monomer 20 is further improved.

[0265] In some embodiments, the second protruding portion 2532 surrounds the outer circumference of the slot of the first slot portion 2541, and the second protruding portion 2532, the first surface 25241 and the second surface 25311 form the second slot portion 2542. The first slot portion 2541 is arranged on the groove bottom wall 2113 of the second slot portion 2542, and the first groove 254 includes the second slot portion 2542.

[0266] The first surface 25241 and the second surface 25311 jointly form the groove bottom surface of the second slot portion 2542, and the first slot portion 2541 is recessed from the groove bottom surface of the second slot portion 2542. Then, the sidewall surface 25411 of the first slot portion 2541 and the sidewall surface 25421 of the second slot portion 2542 are connected through the first surface 25241 and the second surface 25311. The first slot portion 2541 and the second slot portion 2542 jointly form a stepped first groove 254. The groove bottom wall 2113 of the first slot portion 2541 is the groove bottom wall 2113 of the first groove 254. The inner circumferential surface 25321 of the second protruding portion is the sidewall surface 25421 of the second slot portion.

[0267] The second protruding portion 2532 is arranged around the outer periphery of the slot of the first slot portion 2541, and the surface of the second protruding portion 2532 away from the first surface 25241 is an annular surface around the axis of the through hole 2131, which can increase the connection area between the protective piece 26 and the second protruding portion 2532 and improve the stability of the connection between the protective piece 26 and the second protruding portion 2532. The second protruding portion 2532, the first surface 25241 and the second surface 25311 form a second slot portion 2542, the first groove 254 includes the second slot portion 2542, and the first groove 254 includes the second slot portion 2542. The first slot portion 2541 and the second slot portion 2542 together form a stepped first groove 254, which is beneficial to improve the thickness uniformity of each part of the pressure relief component 25.

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

[0269] The protective piece 26 is arranged corresponding to the slot of the first groove 254, and the protective piece 26 completely covers the first groove 254.

[0270] By covering the first groove 254 with the protective piece 26, the protective piece 26 can better protect the weak portion 2521.

[0271] As shown in FIG. 1, Figures 9-11 In some embodiments, along the thickness direction X of the first wall portion, the main body portion 252 is provided with a second groove 255 on the side away from 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 side wall 2112 of the second groove 255. Along the radial direction of the through hole 2131, the second portion 2523 has a second region 25231 arranged opposite to the first portion 2522, and the second region 25231 forms another side wall 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 a groove bottom wall 2113 of the second groove 255.

[0273] By providing the second groove 255 on the side of the main body portion 252 away from the first groove 254, and locating the limiting portion 253 and the weak portion 2521 on both sides of the width direction of the second groove 255 respectively, the second groove 255 can form a buffer zone between the limiting portion 253 and the weak portion 2521, thereby reducing the influence of the stress on the main body portion 252 on the connecting portion 251, further reducing the risk of the connecting portion 251 caused by unbalanced stress on both sides, and improving the reliability of the battery monomer 20 and prolonging the service life of the battery monomer 20.

[0274] As shown in FIG. 1,Figures 7-10 、 Figures 12-16 、 Figures 18-22 As shown in FIG. 25, in some embodiments, the limiting portion 253 abuts the inner side of the first wall portion 213 along the thickness direction X of the first wall portion.

[0275] That is, 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 be in contact with the surface of the first wall portion 213 facing the electrode assembly 22. The surface of the first wall portion 213 in contact with the limiting portion 253 can or can not be the surface of the first wall portion 213 closest to the electrode assembly 22.

[0276] By abutting the limiting portion 253 with the inner side of the first wall portion 213, that is, by locating the limiting portion 253 on the inner side of the first wall portion 213, the limiting portion 253 is accommodated in the housing 21, which is conducive to reducing the volume of the battery monomer 20 and improving the energy density of the battery monomer 20. By abutting the limiting portion 253 with the inner side of the first wall portion 213, when the limiting portion 253 bears the pressure inside the battery monomer 20, the first wall portion 213 can limit the limiting portion 253, which is conducive to improving the ability of the pressure relief component 25 to resist the internal pressure of the battery monomer 20 and also improving the stability of the pressure relief component 25 under the action of the internal pressure of the battery monomer 20.

[0277] In embodiments in which the limiting portion 253 abuts the inner side of the first wall portion 213, at least part of the main portion 252 is arranged in the through hole 2131, and along the thickness direction X of the first wall portion, the main portion 252 has a first surface 25241 facing away from the electrode assembly 22, the first wall portion 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 first surface 25241 and the third surface 2133 are connected by the outer surface of the connecting portion 251.

[0278] The first surface 25241 can or can not be the surface of the main portion 252 farthest away from the electrode assembly 22. The third surface 2133 can or can not be the surface of the first wall portion 213 farthest away from the electrode assembly 22. For example, Figure 21As shown, the first surface 25241 is the surface of the first body 2524 of the main body 252 farthest from the electrode assembly 22, and the third surface 2133 is the surface of the first wall 213 farthest from the electrode assembly 22. The first wall 213 and the main body 252 can be welded at the junction of the first surface 25241 and the third surface 2133 from the outside of the first wall 213 to form the connecting portion 251 (welding mark), and 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] By aligning the first surface 25241 of the main body 252 facing away from the electrode assembly 22 with the third surface 2133 of the first wall 213 facing away from the electrode assembly 22, the first wall 213 and the pressure relief component 25 can be connected to form the connecting portion 251 at the junction of the first surface 25241 and the third surface 2133.

[0280] As shown, Figures 7-22 In some embodiments, the main body 252 includes the first body 2524 and the first protrusion 2525. The first surface 25241 is the surface of the first body 2524 facing away from the electrode assembly 22 along the thickness direction X of the first wall, and the first protrusion 2525 protrudes from the first surface 25241. The battery monomer 20 further includes the protective piece 26 connected to one end of the first protrusion 2525 facing away from the first surface 25241 and forming a gap with the weak portion 2521.

[0281] The first surface 25241 is the surface of the first body 2524 farthest from the electrode assembly 22 along the thickness direction X of the first wall. The first protrusion 2525 protrudes from the first surface 25241, and the first surface 25241 exceeds the outer peripheral surface of the first protrusion 2525 and the inner peripheral surface 25251 of the first protrusion along the radial direction of the through hole 2131. 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 through the outer surface of the connecting portion 251.

[0282] The protective piece 26 is connected to one end of the first protrusion 2525 facing away from the first surface 25241, so that the protective piece 26 is located on the outside of the battery monomer 20, facilitating the arrangement of the protective piece 26 so that the protective piece 26 does not occupy the space inside the shell 21, which is beneficial to improve the energy density of the battery monomer 20.

[0283] By protruding the first protruding part 2525 from the first surface 25241 of the first body 2524 facing away from the electrode assembly 22, the protective piece 26 is connected to one end of the first protruding part 2525 facing away from the first surface 25241, and forms a gap with the weak part 2521. The protective piece 26 can not only protect the weak part 2521, but also provide more space for the pressure relief part 25 to release the internal pressure of the battery monomer 20, so as to avoid the influence of the protective piece 26 on the weak part 2521 to release the internal pressure of the battery monomer 20, so that the battery monomer 20 can be timely relieved, and the reliability of the battery monomer 20 is further improved. By protruding the first protruding part 2525 from the first surface 25241 of the first body 2524 facing away from the electrode assembly 22, the protective piece 26 is connected to one end of the first protruding part 2525 facing away from the first surface 25241, and the first protruding part 2525 and the protective piece 26 can not occupy the space inside the shell 21, which is beneficial to improve the energy density of the battery monomer 20, and the protective piece 26 can also reduce the risk of the external structure of the battery monomer 20 damaging the weak part 2521, and improve the reliability of the battery monomer 20.

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

[0285] In the direction of the thickness X of the first wall part, the first wall part 213 has a third surface 2133 facing away from the electrode assembly 22, and the first accommodating groove 2132 is recessed from the third surface 2133 to the direction close to the electrode assembly 22. Among them, the third surface 2133 can be the surface of the first wall part 213 farthest away from the electrode assembly 22, or can not be the surface of the first wall part 213 farthest away from the electrode assembly 22.

[0286] In the direction of the electrode assembly 22 pointing to the first wall part 213, the surface of the main body part 252 farthest away from the electrode assembly 22 can be relatively closer to the electrode assembly 22 than the third surface 2133, or the surface of the main body part 252 farthest away from the electrode assembly 22 can be flush with the third surface 2133, so that the main body part 252 does not exceed the groove bottom surface 21321 of the first accommodating groove.

[0287] By the body part 252 not exceeding the groove bottom surface 21321 of the first accommodating groove, the space occupied by the pressure relief component 25 outside the battery monomer 20 is reduced, which is beneficial to reduce the volume of the battery monomer 20 and improve the energy density of the battery monomer 20. By the body part 252 not exceeding the groove bottom surface 21321 of the first accommodating groove, the risk of interference between the pressure relief component 25 and the external device is reduced, thereby reducing the risk of external impact on the pressure relief component 25, and further improving the reliability of the battery monomer 20.

[0288] As shown in Figure 21 , Figure 22 In some embodiments, the groove bottom surface 21321 of the first accommodating groove is flush with the surface of the body part 252 farthest away from the electrode assembly 22.

[0289] The welding can be performed at the junction between the groove bottom surface 21321 of the first accommodating groove and the surface of the body part 252 away from the electrode assembly 22 to form the connecting part 251. Of course, the limiting part 253 and the groove bottom wall 2113 of the first accommodating groove 2132 can also be welded to form the connecting part 251.

[0290] By making the groove bottom surface 21321 of the first accommodating groove flush with the surface of the body part 252 farthest away from the electrode assembly 22, the surface of the body part 252 away from the electrode assembly 22 has a distance from the first wall part 213, which reduces the risk of external structure damaging the weak part 2521 and improves the reliability of the battery monomer 20. By making the groove bottom surface 21321 of the first accommodating groove flush with the surface of the body part 252 farthest away from the electrode assembly 22, the space occupied by the pressure relief component 25 outside the shell 21 is reduced, which is beneficial to reduce the volume of the battery monomer 20.

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

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

[0293] The second accommodating groove 2134 is arranged on one side of the first wall portion 213 in the thickness direction of the first wall portion 213, and the limiting portion 253 is accommodated in the second accommodating groove 2134, which is beneficial to reducing the volume of the battery monomer 20.

[0294] As shown in Figure 9 , Figure 10 in some embodiments, along the thickness direction of the first wall portion 213, the first wall portion 213 has a fourth surface 2135 closest to the electrode assembly 22, and the second accommodating groove 2134 is arranged 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 protrude beyond the fourth surface 2135.

[0295] Along the direction of the first wall portion 213 pointing to the electrode assembly 22, the surface of the limiting portion 253 closest to the electrode assembly 22 is farther away from the electrode assembly 22 than 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 protrude beyond the fourth surface 2135 of the second accommodating groove 2134 along the direction of the first wall portion 213 pointing to the electrode assembly 22.

[0296] By arranging the second accommodating groove 2134 on the fourth surface 2135 of the first wall portion 213 closest to the electrode assembly 22 in the thickness direction of the first wall portion 213, and accommodating the limiting portion 253 in the second accommodating groove 2134 without protruding beyond the fourth surface 2135, the limiting portion 253 can not occupy the internal space of the shell 21, which is beneficial to improving the energy density of the battery monomer 20. After the limiting portion 253 is accommodated in the second accommodating groove 2134 without protruding beyond the fourth surface 2135, the distance between the limiting portion 253 and the electrode assembly 22 is larger, which reduces the risk of damaging the electrode assembly 22 when the first wall portion 213 is connected with the pressure relief component 25.

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

[0298] That is, the limiting portion 253 is located on the side of the first wall portion 213 away from the electrode assembly 22. The limiting portion 253 can be in contact with the surface of the first wall portion 213 away from the electrode assembly 22. The surface of the first wall portion 213 in contact with the limiting portion 253 can be the surface of the first wall portion 213 farthest away from the electrode assembly 22, or can not be the surface of the first wall portion 213 farthest away from the electrode assembly 22.

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

[0300] As shown in Figure 27 , Figure 28As shown, in some embodiments, along the thickness direction of the first wall portion 213, the first wall portion 213 has a fourth surface 2135 closest to the electrode assembly 22; 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] like Figures 9-10 , Figures 15-16 , Figures 21-22 , Figures 27-28 As shown, 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 abutting against the limiting portion 253 is D, the thickness of the limiting portion 253 is d, and D / 5≤d≤5D.

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

[0310] By d≥D / 5, the limiting portion 253 has sufficient thickness to connect with the first wall portion 213, so that the connecting portion 251 formed by the connection of the limiting portion 253 and the first wall portion 213 has a larger connecting area, which is beneficial to improve the connection stability of the pressure relief component 25 and the first wall portion 213. In the case of realizing the connection of the first wall portion 213 and the limiting portion 253 by welding, d≥D / 5 can reduce the risk of the limiting portion 253 being welded through while ensuring a larger depth of the molten pool, thereby improving the connection stability of the first wall portion 213 and the limiting portion 253 and the strength of the lamination area of the limiting portion 253 and the first wall portion 213. By d≤5D, the space occupied by the limiting portion 253 can be reduced. If the limiting portion 253 is located on the inner side of the first wall portion 213, the space occupied by the limiting portion 253 in the interior of the shell 21 can be reduced, thereby improving the energy density of the battery monomer 20. If the limiting portion 253 is located on the outer side of the first wall portion 213, the space occupied by the limiting portion 253 outside the battery monomer 20 can be reduced, which is beneficial to reduce the volume of the battery monomer 20. Therefore, D / 5≤d≤5D can not only make the connection stability of the pressure relief component 25 and the first wall portion 213 better, but also reduce the space occupied by the limiting portion 253.

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

[0312] Exemplarily, 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 d≥D / 3, the limiting portion 253 has a larger thickness connected with the first wall portion 213, so that the connecting portion 251 formed by the connection of the limiting portion 253 and the first wall portion 213 has a larger connecting area, which is beneficial to improve the connecting stability of the pressure relief component 25 and the first wall portion 213. In the case of realizing the connection of the first wall portion 213 and the limiting portion 253 by welding, d≥D / 3 can reduce the risk of the limiting portion 253 being welded through while ensuring a larger depth of the molten pool, further improving the connecting stability of the first wall portion 213 and the limiting portion 253 and the strength of the lamination area of the limiting portion 253 and the first wall portion 213. By d≤2D, the space occupied by the limiting portion 253 can be further reduced. If the limiting portion 253 is located on the inner side of the first wall portion 213, the space occupied by the limiting portion 253 in the interior of the shell 21 can be further reduced, improving the energy density of the battery monomer 20. If the limiting portion 253 is located on the outer side of the first wall portion 213, the space occupied by the limiting portion 253 outside the battery monomer 20 can be further reduced, which is beneficial to reduce the volume of the battery monomer 20. Therefore, D / 3≤d≤2D can not only make the connecting stability of the pressure relief component 25 and the first wall portion 213 better, but also further reduce the space occupied by the limiting portion 253.

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

[0315] The end cover 212 is the first wall portion 213, and the pressure relief component 25 is arranged on the end cover 212. The end cover 212 and the pressure relief component 25 are arranged separately and connected.

[0316] The end cover 212 is the first wall portion 213. By installing the pressure relief component 25 on the end cover 212, the end cover 212 can be located at the top of the battery monomer 20, which can reduce the risk of electrolyte corroding the pressure relief component 25, improve the working stability of the pressure relief component 25, and reduce the risk of electrolyte seeping into the pressure relief component 25, which can improve the reliability of the battery monomer 20 and prolong the service life of the battery monomer 20.

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

[0318] The first wall portion 213 is part of a wall portion of the housing 211. The first wall portion 213 can be any wall portion of the shell 21 except the end cover 212.

[0319] The pressure relief component 25 is arranged on the wall portion of the shell 211, which is conducive to improving the energy density of the battery monomer 20.

[0320] As shown in some embodiments, the shell 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 the first wall portion 213. Figures 19-22

[0321] The bottom wall 2113 supports the electrode assembly 22, and the bottom wall 2113 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 arranged on the bottom wall 2113. The bottom wall 2113 and the pressure relief component 25 are arranged separately and connected. The side wall 2112 surrounds the outer periphery of the electrode assembly 22.

[0322] By arranging the pressure relief component 25 on the bottom wall 2113, the risk of damage to other structures inside the battery monomer 20 caused by the heat released by the pressure relief component 25, and other problems such as fire and explosion can be reduced, and the reliability of the battery monomer 20 can be improved.

[0323] As shown in some embodiments, the shell 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 the first wall portion 213. Figures 12-16 Figures 24-28 As shown in some embodiments, the shell 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 the first wall portion 213.

[0324] The side wall 2112 surrounds the outer periphery of the electrode assembly 22. The first wall portion 213 is a part of the side wall 2112.

[0325] The side wall 2112 includes the first wall portion 213, and by arranging the pressure relief component 25 on the side wall 2112, the energy density of the battery monomer 20 can be improved.

[0326] As shown in some embodiments, the side wall 2112 includes a first side wall 21121 and a second side wall 21122 arranged adjacent to each other, the area of the outer surface of the first side wall 21121 is greater than the area of the outer surface of the second side wall 21122; the second side wall 21122 is the first wall portion 213. Figures 12-16 Figures 24-28 As shown in some embodiments, the side wall 2112 includes a first side wall 21121 and a second side wall 21122 arranged adjacent to each other, the area of the outer surface of the first side wall 21121 is greater than the area of the outer surface of the second side wall 21122; the second side wall 21122 is the 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 mixed. Mixed connection means that there are 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] The battery cell 20 provided by the embodiments of the present application comprises a housing 21, an electrode assembly 22 and a pressure relief component 25. The electrode assembly 22 is accommodated in the housing 21, and a first wall portion 213 of the housing 21 and the pressure relief component 25 are welded to form a connecting portion 251.

[0336] The pressure relief component 25 comprises a limiting portion 253 and a main body portion 252. The limiting portion 253 is connected to the outer circumferential surface of the main body portion 252 and has a structure closed in the circumferential direction of the through hole 2131. The main body portion 252 is arranged opposite to the through hole 2131 of the first wall portion 213, and has a weak portion 2521 configured to be able to be damaged to release the pressure inside the battery cell 20. Part of the main body portion 252 is inserted into the through hole 2131.

[0337] The first wall portion 213 is the end cover 212 of the housing 21 or the bottom wall 2113 of the shell 211 or the side wall 2112 of the shell 211. The main body portion 252 is inserted into the through hole 2131. On the side of the main body portion 252 away from the electrode assembly 22 in the thickness direction X of the first wall portion, a first groove 254 is arranged. On the surface of the pressure relief component 25 farthest away from the electrode assembly 22 in the thickness direction X of the first wall portion, a protective piece 26 is connected, which covers the first groove 254.

[0338] In 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, and the fourth surface 2135 is provided with a second accommodating groove 2134 in which the limiting portion 253 is accommodated. In 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 all exceed the fourth surface 2135.

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

[0340] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0341] The above embodiments are only used to illustrate the technical solutions of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized by, The battery monomer comprises: a shell having a first wall part provided with a through hole; an electrode assembly accommodated in the shell; a pressure relief component connected with the first wall part to form a connecting part, the pressure relief component comprising a main body part and a limiting part connected with the main body part and surrounding at least part of the outer periphery of the main body part, the main body part being oppositely arranged with the through hole, the main body part having a weak part configured to be broken to release the pressure inside the battery monomer; wherein, along the thickness direction of the first wall part, the limiting part abuts against the first wall part, and in the projection plane perpendicular to the thickness direction of the first wall part, at least part of the orthographic projection of the limiting part is located outside the orthographic projection of the connecting part.

2. The battery cell of claim 1, wherein, The main body part and the first wall part form the connecting part.

3. The battery cell of claim 2, wherein the cathode comprises a lithium metal oxide. The main body part comprises 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 two ends of the first part, and the weak part being arranged on the second part. The first part and the first wall part form the connecting part.

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

5. The battery cell of claim 3, wherein the cathode comprises a lithium metal oxide. Along the radial direction of the through hole, the connecting part and the surface of the first part away from the hole wall surface of the through hole have a first distance K, the thickness of the limiting part is d, and d / 10≤K≤4d; optionally, d / 5≤K≤3d / 2.

6. The battery cell of claim 1, wherein, Along the thickness direction of the first wall part, the connecting part extends from the surface of the first wall part away from the limiting part to the limiting part.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. There is a second distance H between the connecting part and the surface of the limiting part away from the first wall part, the thickness of the limiting part is d, and d / 10≤H≤2d; optionally, d / 5≤H≤d.

8. The battery cell of any one of claims 1-7, wherein, The main body part is at least partially arranged in the through hole.

9. The battery cell of any one of claims 1-7, wherein, Along the thickness direction of the first wall part, one side of the pressure relief component is provided with a first groove, the weak part is arranged on the groove bottom wall of the first groove, and at least part of the first groove is arranged in the main body part. The battery monomer further comprises a protective piece connected with the pressure relief component, the protective piece being arranged on the groove bottom wall of the first groove away from the electrode assembly and having a gap with the groove bottom wall of the first groove along the thickness direction of the first wall part.

10. The battery cell of claim 9, wherein the cathode comprises a lithium metal oxide. The main body part comprises a first body and a first protruding part, along the thickness direction of the first wall part, the first body has a first surface, the first protruding part is protrudingly arranged on the first surface, the first surface is provided with a first groove part, the first groove comprises the first groove part, and the weak part is arranged on the groove bottom wall of the first groove part. The protective piece is connected to one end of the first protruding part away from the first surface.

11. The battery cell of claim 10, wherein the cathode comprises a lithium metal oxide. The first protrusion surrounds the outer periphery of the opening of the first groove, the first protrusion and the first surface form a 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, characterized in that, 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, characterized in that, 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 as described in claim 9, characterized in that, The protective component covers the first groove.

15. The battery cell as claimed in claim 9, 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 of any one of claims 1-7, 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 described in claim 16, characterized in that, 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 connected by the outer surface of the connecting portion.

18. The battery cell of 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 described in claim 16, characterized in that, 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 of claim 19, wherein the cathode comprises a lithium metal oxide. 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 of any one of claims 1-7, 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 described in claim 21, characterized in that, The first wall portion has a fourth surface closest to the electrode assembly in the thickness direction of the first wall portion, and the second accommodating groove is arranged on the fourth surface.

23. The battery cell according to any one of claims 1-7, characterized in that, The limiting portion abuts against the outside of the first wall portion in the thickness direction of the first wall portion.

24. The battery cell of any one of claims 1-7, wherein, The first wall portion has a fourth surface closest to the electrode assembly in the thickness direction of the first wall portion. The weak portion does not exceed the fourth surface.

25. The battery cell of any one of claims 1-7, wherein, The main body portion does not exceed the surface of the limiting portion away from the first wall portion in the thickness direction of the first wall portion.

26. The battery cell of claim 1, wherein, The limiting portion and the first wall portion are connected to form the connecting portion, and the connecting portion is located on the inner side of the peripheral surface of the limiting portion.

27. The battery cell of any one of claims 1-7, wherein, The thickness of the portion of the first wall portion abutting against the limiting portion is D, and the thickness of the limiting portion is d, and D / 5≤d≤5D; optionally, D / 3≤d≤2D.

28. The battery cell of any one of claims 1-7, wherein, The shell comprises a shell body and an end cover, the shell body has an opening, and the end cover closes the opening, and the end cover is the first wall portion.

29. The battery cell of any one of claims 1-7, wherein, The shell comprises a shell body and an end cover, the shell body has an opening, and the end cover closes the opening, and the shell body comprises the first wall portion.

30. The battery cell as described in claim 29, characterized in that, The shell comprises a bottom wall and a side wall surrounding the bottom wall, one end of the bottom wall is connected to the side wall, and the other end of the side wall forms the opening. The bottom wall is the first wall portion.

31. The battery cell of claim 30, wherein the cathode comprises a lithium metal oxide. The shell comprises a bottom wall and a side wall surrounding the bottom wall, one end of the bottom wall is connected to the side wall, and the other end of the side wall forms the opening. The side wall comprises the first wall portion.

32. The battery cell of claim 31, wherein the cathode comprises a lithium metal oxide. The side wall comprises a first side wall and a second side wall arranged adjacent to each other, and the area of the outer surface of the first side wall is greater than the area of the outer surface of the second side wall. The second side wall is the first wall portion.

33. A battery device, characterized by The battery cell as claimed in any one of claims 1-32.

34. An electrical device, comprising: The battery device as claimed in claim 33.

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