Battery cell, pressure-relief mechanism and manufacturing method therefor, battery device and electric device

Abstract

Provided are a battery cell, a pressure-relief mechanism and a manufacturing method therefor, a battery device, and an electric device. The battery cell comprises a casing, wherein the casing has a wall portion, and the base material of the wall portion is iron. An electrode assembly is accommodated in the casing. The base material of the pressure-relief mechanism is iron. The pressure-relief mechanism comprises a weakened portion, a body portion and a connection portion, wherein the weakened portion is configured to rupture when the internal pressure of the casing reaches a threshold value; the body portion is located in an area enclosed by the weakened portion; and the connection portion is located on the outer side of the weakened portion and is connected to the wall portion. The part of the body portion close to the weakened portion is a first part, and the part of the connection portion close to the weakened portion is a second part, at least one of the first part and the second part extending relative to the weakened portion in the direction closer to or away from the electrode assembly. At least one of the first part and the second part extending relative to the weakened portion facilitates material flow during stamping of the weakened portion, helping ensure consistent burst pressures among a plurality of manufactured battery cells, improving the reliability of the battery cells.

Description

Battery cell, pressure relief mechanism and manufacturing method thereof, battery device and electric device TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to a battery cell, a pressure relief mechanism and a manufacturing method thereof, a battery device and an electric device. BACKGROUND

[0002] Batteries are widely used in the field of new energy, for example, electric vehicles, new energy vehicles, etc. New energy vehicles and electric vehicles have become a new trend in the development of the automobile industry. The development of battery technology needs to consider various design factors, such as energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the battery is poor at present.

[0003] SUMMARY

[0004] The purpose of the embodiments of the present application is to provide a battery cell, a pressure relief mechanism and a manufacturing method thereof, a battery device and an electric device, which aims to improve the problem of poor reliability of the battery in the related art.

[0005] In a first aspect, the embodiments of the present application provide a battery cell, which comprises a shell, an electrode assembly and a pressure relief mechanism, the shell has a wall part, the base material of the wall part is iron; the electrode assembly is contained in the shell; the base material of the pressure relief mechanism is iron, the pressure relief mechanism comprises a weak part, a body part and a connecting part, the weak part is configured to be at least partially destroyed to release the pressure when the pressure inside the shell reaches a threshold value, the body part is located in the area surrounded by the weak part, the connecting part is located on the outside of the weak part and is connected to the wall part, a part of the body part close to the weak part is a first part, a part of the connecting part close to the weak part is a second part, and at least one of the first part and the second part extends relative to the weak part in the direction of approaching or moving away from the electrode assembly.

[0006] In the above technical solution, by making at least one of the first part and the second part extend relative to the weak part in the direction of approaching or moving away from the electrode assembly, the flow of material is facilitated when the weak part is stamped and formed, which is beneficial to improve the stress of the weak part, so that the formed weak part has good structural stability and is not prone to appear concave-convex wavy structure, which is beneficial to keep the burst pressure of multiple battery cells consistent when the multiple battery cells are manufactured, and is beneficial to improve the reliability of the battery cell. Furthermore, when the battery cell expands, the wall part is deformed under stress, and at least one of the first part and the second part extending relative to the weak part can be stretched under external force, thereby reducing the pulling of the weak part by the external force and reducing the risk of the weak part being destroyed prematurely, which is beneficial to improve the service life and reliability of the battery cell.

[0007] As an optional technical solution of the embodiment of the present application, the difference between the surface roughness of the first part and the surface roughness of the weak part is less than or equal to Ra 0.3, and / or the difference between the surface roughness of the second part and the surface roughness of the weak part is less than or equal to Ra 0.3.

[0008] In the above technical solution, the surface roughness of the first part and the surface roughness of the weak part are basically consistent, and the surface roughness of the second part and the surface roughness of the weak part are basically consistent. In this way, the weak part can be formed by stamping, and the roughness of the weak part is lower, so that the thickness consistency of different positions of the weak part is higher, which is more conducive to improving the consistency of the burst pressure.

[0009] As an optional technical solution of the embodiment of the present application, the surface roughness of the weak part, the surface roughness of the first part and the surface roughness of the second part are the same.

[0010] In the above technical solution, the surface roughness of the first part and the surface roughness of the weak part are consistent, and the surface roughness of the second part and the surface roughness of the weak part are consistent. In this way, the weak part can be formed by stamping, and the roughness of the weak part is lower, so that the thickness consistency of different positions of the weak part is higher, which is more conducive to improving the consistency of the burst pressure.

[0011] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, the bottom wall of the pressure relief groove forms the weak part; the groove side surface of the pressure relief groove and the groove bottom surface of the pressure relief groove are transitioned through a round corner; and / or the pressure relief mechanism includes a first surface, the pressure relief groove is arranged on the first surface, and the groove side surface of the pressure relief groove and the first surface are transitioned through a round corner.

[0012] In the above technical solution, the weak part is formed on the pressure relief mechanism by opening the pressure relief groove on the pressure relief mechanism. When the battery cell is relieved, the pressure relief mechanism is cracked along at least part of the weak part, which is simple and convenient, and has low cost. By making the groove side surface of the pressure relief groove and the groove bottom surface of the pressure relief groove transition through a round corner, it is conducive to reducing stress concentration and improving the consistency of the burst pressure. By making the groove side surface of the pressure relief groove and the first surface transition through a round corner, it is conducive to reducing stress concentration and improving the consistency of the burst pressure.

[0013] As an optional technical solution of the embodiment of the present application, the material of the wall part includes at least one of stainless steel and carbon steel; and the material of the pressure relief mechanism includes at least one of stainless steel and carbon steel.

[0014] In the technical solution, the stainless steel and the carbon steel have high strength, which can effectively improve the structural strength of the wall portion and the pressure relief mechanism, reduce the risk of deformation of the wall portion and the pressure relief mechanism under stress, and help reduce the risk of early valve opening and pressure relief of the pressure relief mechanism, thereby improving the service life and reliability of the battery monomer. In addition, the wall portion is made of at least one of the stainless steel and the carbon steel, which can appropriately reduce the thickness of the wall portion, increase the internal space of the shell under the same volume, and thereby increase the energy density.

[0015] As an optional technical solution of the embodiment, the material of the wall portion includes at least one of SU304 stainless steel, SU305 stainless steel, or SU316L stainless steel; and the material of the pressure relief mechanism includes at least one of SU304 stainless steel, SU305 stainless steel, or SU316L stainless steel.

[0016] In the technical solution, the 304 stainless steel, the 305 stainless steel, and the 316L stainless steel have advantages of corrosion resistance, high temperature resistance, and good processing performance. The wall portion and the pressure relief mechanism made of the 304 stainless steel, the 305 stainless steel, or the 316L stainless steel have high strength, which can reduce the risk of deformation of the wall portion and the pressure relief mechanism under stress, help reduce the risk of early valve opening and pressure relief of the pressure relief mechanism, improve the service life and reliability of the battery monomer, and improve the consistency of the detonation pressure of the plurality of battery monomers.

[0017] As an optional technical solution of the embodiment, the thickness of the body portion is H1, which satisfies 0.05mm≤H1≤0.5mm; and / or the thickness of the connecting portion is H2, which satisfies 0.05mm≤H2≤0.5mm.

[0018] In the technical solution, when H1≥0.05mm, the thickness of the body portion is large, the body portion has high structural strength, which can reduce the risk of deformation of the body portion under stress, and help improve the service life and reliability of the battery monomer. When H1≤0.5mm, the thickness of the body portion is not too large, which is helpful to control the manufacturing cost of the battery monomer. Therefore, when 0.05mm≤H1≤0.5mm, the service life, reliability, and manufacturing cost of the battery monomer can be considered.

[0019] When H2≥0.05mm, the thickness of the connecting portion is large, the connecting portion has high structural strength, which can reduce the risk of deformation of the connecting portion under stress, and help improve the service life and reliability of the battery monomer. When H2≤0.5mm, the thickness of the connecting portion is not too large, which is helpful to control the manufacturing cost of the battery monomer. Therefore, when 0.05mm≤H2≤0.5mm, the service life, reliability, and manufacturing cost of the battery monomer can be considered.

[0020] As an optional technical solution of the embodiment of the present application, the extension height of at least one of the first part and the second part extending relative to the weak part is in the range of [0.2mm, 7mm].

[0021] In the above technical solution, when the extension height of at least one of the first part and the second part extending relative to the weak part is greater than or equal to 0.2mm, the extension height of at least one of the first part and the second part extending relative to the weak part is large, which is beneficial to flow material when the weak part is formed by stamping, and is beneficial to improve the stress of the weak part, so that the formed weak part has good structural stability. When the extension height of at least one of the first part and the second part extending relative to the weak part is less than or equal to 7mm, the extension height of at least one of the first part and the second part extending relative to the weak part is not too large, on the one hand, which is beneficial to reduce the occupation of the internal space of the battery device or the battery monomer, and improve the energy density of the battery device or the battery monomer, on the other hand, which is beneficial to reduce the risk of interference with other components. Therefore, when the extension height of at least one of the first part and the second part extending relative to the weak part is in the range of [0.2mm, 7mm], the life and energy density of the battery monomer can be considered, and the risk of interference with other components can be reduced.

[0022] As an optional technical solution of the embodiment of the present application, the extension height of at least one of the first part and the second part extending relative to the weak part is in the range of [0.3mm, 5mm].

[0023] In the above technical solution, when the extension height of at least one of the first part and the second part extending relative to the weak part is greater than or equal to 0.3mm, the extension height of at least one of the first part and the second part extending relative to the weak part is larger, which is beneficial to flow material when the weak part is formed by stamping, and is beneficial to improve the stress of the weak part, so that the formed weak part has good structural stability. When the extension height of at least one of the first part and the second part extending relative to the weak part is less than or equal to 5mm, the extension height of at least one of the first part and the second part extending relative to the weak part is not too large, on the one hand, which is beneficial to reduce the occupation of the internal space of the battery device or the battery monomer, and improve the energy density of the battery device or the battery monomer, on the other hand, which is beneficial to reduce the risk of interference with other components. Therefore, when the extension height of at least one of the first part and the second part extending relative to the weak part is in the range of [0.3mm, 5mm], the life and energy density of the battery monomer can be considered, and the risk of interference with other components can be reduced.

[0024] As an optional technical solution of the embodiment of the present application, the first part at least partially extends relative to the weak part in the direction of approaching or moving away from the electrode assembly.

[0025] In the technical solution, the first part extends at least partially in the direction of approaching or moving away from the electrode assembly relative to the weak part. This not only facilitates the flow of material when the weak part is formed by stamping, but also improves the stress of the weak part, and increases the contact area with the internal gas, thereby facilitating the cracking of the weak part to release pressure. In this way, under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easy to crack in advance due to the change of the pressure inside the battery monomer or the external impact during normal use of the battery monomer, which is conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery monomer. Compared with the aluminum material explosion valve in the prior art, the thickness of the weak part of the pressure release mechanism provided by the embodiment of the application is smaller. When manufacturing, a slight change in the thickness of the weak part will cause a great change in the burst pressure of the battery monomer. By extending the first part at least partially in the direction of approaching or moving away from the electrode assembly relative to the weak part, the thickness of the weak part can be increased under the same burst pressure, and the larger the thickness of the weak part, the easier it is to manufacture, thereby improving the consistency of the burst pressure of multiple battery monomers.

[0026] As an optional technical solution of the embodiment of the application, the first part extends entirely in the direction of moving away from the electrode assembly relative to the weak part.

[0027] In the technical solution, the existing pressure release mechanism will gradually arch away from the electrode assembly under the action of the pressure inside the battery monomer when releasing pressure, and then open under the action of the pressure inside the battery monomer. In the embodiment of the application, the first part extends entirely in the direction of moving away from the electrode assembly relative to the weak part, forming a pre-deformation, thereby facilitating the cracking of the weak part to release pressure. In this way, under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easy to crack in advance due to the change of the pressure inside the battery monomer or the external impact during normal use of the battery monomer, which is conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery monomer. By extending the first part entirely in the direction of moving away from the electrode assembly relative to the weak part, the contact area between the body part and the internal gas is larger when the battery monomer releases pressure, the external force applied to the first part is larger, the first part can directly pull the weak part, and the shear force received by the weak part is larger, thereby facilitating the opening of the weak part to release pressure. Under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easy to crack in advance due to the change of the pressure inside the battery monomer or the external impact during normal use of the battery monomer, which is conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery monomer. In addition, the larger the thickness of the weak part, the easier it is to manufacture, thereby improving the consistency of the burst pressure of multiple battery monomers.

[0028] As an optional technical solution of the embodiment of the present application, a part of the first part extends away from the electrode assembly relative to the weak portion.

[0029] In the above technical solution, the existing pressure relief mechanism will gradually arch away from the electrode assembly under the action of the internal pressure of the battery monomer when the pressure relief mechanism is in the pressure relief state, and then open the pressure relief under the action of the internal pressure of the battery monomer. In the embodiment of the present application, a part of the first part extends away from the electrode assembly relative to the weak portion, forming a pre-deformation, thereby facilitating the opening of the weak portion. In this way, under the same burst pressure, the thickness of the weak portion can be larger, and the weak portion is not easy to be broken in advance due to the change of the internal pressure of the battery monomer or external impact during normal use of the battery monomer, which is beneficial to reduce the risk of the weak portion being damaged in advance and improve the service life of the battery monomer. By extending a part of the first part away from the electrode assembly relative to the weak portion, the contact area between the body portion and the internal gas is larger when the battery monomer is in the pressure relief state, and the external force applied to the first part is larger. The first part can directly pull the weak portion, so that the weak portion receives a larger shear force, thereby facilitating the opening of the weak portion. Under the same burst pressure, the thickness of the weak portion can be larger, and the weak portion is not easy to be broken in advance due to the change of the internal pressure of the battery monomer or external impact during normal use of the battery monomer, which is beneficial to reduce the risk of the weak portion being damaged in advance and improve the service life of the battery monomer. In addition, the larger the thickness of the weak portion, the easier it is to manufacture, thereby facilitating the consistency of the burst pressure of multiple battery monomers. In addition, extending a part of the first part away from the electrode assembly relative to the weak portion is beneficial to control the extension height of the body portion.

[0030] As an optional technical solution of the embodiment of the present application, the electrode assembly includes at least two layers of pole pieces; the at least two layers of pole pieces are stacked, and the stacking direction of the at least two layers of pole pieces is the first direction; or, the at least two layers of pole pieces are wound, and the at least two layers of pole pieces each include a flat section located in the middle of the electrode assembly and a curved section located at both ends of the electrode assembly, the stacking direction of the at least two layers of pole pieces at the flat section is the first direction; and the cross section of the body portion in at least one plane perpendicular to the first direction is arched.

[0031] In the technical solution, the cross section of the body part in at least one plane perpendicular to the first direction is arched. On the one hand, the molten material is facilitated to flow when the weak part is formed by stamping, and the stress of the weak part is improved, so that the formed weak part has good structural stability. On the other hand, when the battery cell is depressurized, the contact area between the body part and the internal gas is large, and the external force applied to the body part is large. The body part can better transmit the force to the weak part, thereby pulling the weak part, so that the weak part receives a larger shear force, thereby facilitating the opening of the weak part for pressure relief. Under the same burst pressure, the thickness of the weak part can be larger. When the battery cell is used normally, the weak part is not easy to be broken in advance due to the pressure change in the battery cell or external impact, which is beneficial to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell. On the other hand, when the battery cell expands, the arch shape is more easily stretched under the action of external force, thereby reducing the risk of external force being transmitted to the weak part, further reducing the pulling of the weak part by external force, reducing the risk of the weak part being damaged in advance, and improving the service life of the battery cell.

[0032] As an optional technical solution of the embodiment of the application, the extension height of the first part extending relative to the weak part is H3, and 0.5mm≤H3≤5mm is met.

[0033] In the technical solution, when H3≥0.5mm, the extension height of the first part extending relative to the weak part is high, so that the deformation of the body part is more obvious. Under the same burst pressure, the thickness of the weak part is larger, which is beneficial to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell. When H3≤5mm, the extension height of the first part extending relative to the weak part is not too large. On the one hand, it is beneficial to reduce the occupation of the internal space of the battery device or the battery cell and improve the energy density of the battery device or the battery cell. On the other hand, it is beneficial to reduce the risk of interference between the body part and other components. Therefore, when 0.5mm≤H3≤5mm, the service life and energy density of the battery cell can be considered, and the risk of interference between the body part and other components can be reduced.

[0034] As an optional technical solution of the embodiment of the application, 0.8mm≤H3≤3mm.

[0035] In the technical solution, when H3 is greater than or equal to 0.8 mm, the first part extends to a higher height relative to the weak part, so that the deformation of the body part is more obvious, and under the same blasting pressure, the thickness of the weak part is greater, which is more conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery cell. When H3 is less than or equal to 3 mm, the extension height of the first part relative to the weak part is not too large, on the one hand, it is conducive to reducing the occupation of the internal space of the battery device or the battery cell and improving the energy density of the battery device or the battery cell, and on the other hand, it is conducive to reducing the risk of interference between the body part and other components. Therefore, when 0.8 mm≤H3≤3 mm, the service life and energy density of the battery cell can be better balanced, and the risk of interference between the body part and other components can be reduced.

[0036] As an optional technical solution of the embodiment of the application, the second part extends relative to the weak part in a direction close to or away from the electrode assembly.

[0037] In the technical solution, by extending the second part relative to the weak part in a direction close to or away from the electrode assembly, on the one hand, it is convenient to flow the material when stamping the weak part, and is conducive to improving the stress of the weak part, so that the formed weak part has good structural stability. On the other hand, when the battery cell expands, the second part can be stretched under the action of external force, thereby reducing the risk of external force being transmitted to the weak part, further reducing the pulling of the weak part by external force, reducing the risk of the weak part being damaged in advance, and improving the service life of the battery cell.

[0038] As an optional technical solution of the embodiment of the application, the connecting part includes a third part, the third part is used for connecting with the wall part, and the second part connects the weak part and the third part.

[0039] In the technical solution, the third part is used for connecting with the wall part, and the second wall part connects the weak part and the third part. During manufacturing, since the third part is farther away from the weak part than the second part, the third part is not easily affected during processing of the weak part, so that the third part can maintain the original shape, thereby facilitating connection of the third part with the wall part.

[0040] As an optional technical solution of the embodiment of the application, the third part is parallel to the wall part.

[0041] In the technical solution, by making the third part parallel to the wall part, the third part is more convenient to connect with the wall part, which is conducive to increasing the stability of the connection between the third part and the wall part.

[0042] As an optional technical solution of the embodiment of the application, the second part is arranged obliquely relative to the third part, and an oblique angle of the second part relative to the third part is a, which satisfies: 40°≤a≤75°.

[0043] In the above technical solution, when a≥40°, the oblique degree of the connecting part is large, the constraint effect on the weak part is good, and the risk of creep failure of the weak part is reduced. When a≤75°, the oblique degree of the connecting part is not too large, the stress concentration is reduced, and the risk of brittle fracture is reduced.

[0044] As an optional technical solution of the embodiment of the application, the first part and the second part are both extended relative to the weak part, and the direction in which the first part extends relative to the weak part is the same as the direction in which the second part extends relative to the weak part.

[0045] In the above technical solution, when the direction in which the first part extends relative to the weak part is the same as the direction in which the second part extends relative to the weak part, the first part can extend by using the extension height of the second part, thereby reducing the height of the body part exceeding the surface of the connecting part farthest from the electrode assembly or reducing the height of the body part exceeding the surface of the connecting part closest to the electrode assembly, reducing the occupation of the internal space of the battery device or the battery cell, and improving the energy density of the battery device or the battery cell. In addition, when the battery cell is depressurized, the first part and the second part respectively apply forces in opposite directions to the weak part, so that the weak part is subjected to a shearing force, facilitating the opening of the weak part for pressure relief. Under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easy to be cracked in advance due to the pressure change in the battery cell or external impact during normal use of the battery cell, thereby reducing the risk of damage to the weak part in advance and improving the service life of the battery cell. Moreover, when the battery cell expands, the first part and the second part are more easily stretched under the action of external force, thereby reducing the risk of external force being transmitted to the weak part, further reducing the pulling of the weak part by external force, reducing the risk of damage to the weak part in advance, and improving the service life of the battery cell.

[0046] As an optional technical solution of the embodiment of the application, the first part and the second part are both extended relative to the weak part in a direction close to the electrode assembly.

[0047] In the technical solution, when the first part and the second part extend relative to the weak part in the direction close to the electrode assembly, the first part can extend by the extension height of the second part, so that the height of the body part beyond the surface of the connecting part closest to the electrode assembly is reduced, the internal space of the battery cell is reduced, and the energy density of the battery cell is improved. In addition, when the battery cell is pressure released, the first part and the second part apply forces in opposite directions to the weak part, so that the weak part is subjected to a shearing force, and the weak part is easily opened to release pressure. Under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easily cracked in advance due to the pressure change in the battery cell or external impact during normal use of the battery cell, so as to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell.

[0048] As an optional technical solution of the embodiment, the first part and the second part extend relative to the weak part in the direction away from the electrode assembly.

[0049] In the technical solution, when the first part and the second part extend relative to the weak part in the direction away from the electrode assembly, the first part can extend by the extension height of the second part, so that the height of the body part beyond the surface of the connecting part farthest from the electrode assembly is reduced, the internal space of the battery is reduced, and the energy density of the battery device is improved. In addition, when the battery cell is pressure released, the first part and the second part apply forces in opposite directions to the weak part, so that the weak part is subjected to a shearing force, and the weak part is easily opened to release pressure. Under the same burst pressure, the thickness of the weak part can be larger, and the weak part is not easily cracked in advance due to the pressure change in the battery cell or external impact during normal use of the battery cell, so as to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell.

[0050] As an optional technical solution of the embodiment, the first part and the second part extend relative to the weak part, and the direction in which the first part extends relative to the weak part is opposite to the direction in which the second part extends relative to the weak part.

[0051] In the technical solution, by making the direction in which the first part extends relative to the weak part opposite to the direction in which the second part extends relative to the weak part, the weak part is not easily affected when the connecting part is connected to the wall part, so as to maintain the performance of the weak part and improve the service life of the battery cell.

[0052] As an optional technical solution of the embodiment, the first part extends relative to the weak part in the direction close to the electrode assembly, and the second part extends relative to the weak part in the direction away from the electrode assembly.

[0053] In the technical solution, the first part extends relative to the weak part in a direction close to the electrode assembly, and the second part extends relative to the weak part in a direction away from the electrode assembly, which is conducive to reducing the occupation of the internal space of the battery, improving the energy density of the battery device, and reducing the risk of interference between the body part and other components in the battery.

[0054] As an optional technical solution of the embodiment, the first part extends relative to the weak part in a direction away from the electrode assembly, and the second part extends relative to the weak part in a direction close to the electrode assembly.

[0055] In the technical solution, the first part extends relative to the weak part in a direction away from the electrode assembly, and the second part extends relative to the weak part in a direction close to the electrode assembly, which is conducive to reducing the occupation of the internal space of the battery, improving the energy density of the battery device, and reducing the risk of interference between the body part and other components in the battery.

[0056] As an optional technical solution of the embodiment, the minimum thickness of the weak part is H4, and 0.01mm≤H4≤0.2mm is satisfied.

[0057] In the technical solution, when H4≥0.01mm, the thickness of the weak part is large, and the weak part is not easy to be broken in advance due to the pressure change in the battery or external impact, which is conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery. When H4≤0.2mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery overheats, which is conducive to improving the timeliness of the pressure relief mechanism. Therefore, when 0.01mm≤H4≤0.2mm, the service life of the battery and the timeliness of pressure relief can be considered.

[0058] As an optional technical solution of the embodiment, the projection area of the body part in the thickness direction of the wall part is S; wherein, 100mm 2 ≤450mm 2 , and 0.010mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H4≤0.190mm; or, 1550mm2 ≤S≤2100mm 2 , and 0.030mm≤H4≤0.200mm.

[0059] In the above technical solution, when the projection area of the body part is larger, the body part is more easily affected by the internal pressure to cause the weak part to crack, therefore, when the projection area of the body part is increased, in order to ensure the same blasting pressure, the thickness of the weak part can be increased. When 100mm 2 ≤S≤450mm 2 , and H4≥0.010mm, the thickness of the weak part is larger, and the weak part is not easy to crack in advance due to the change of the internal pressure of the battery monomer or external impact, which is beneficial to reduce the risk of the destruction of the weak part in advance and improve the service life of the battery monomer. When 100mm 2 ≤S≤450mm 2 , and H4≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery monomer is out of control, which is beneficial to improve the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 100mm 2 ≤S≤450mm 2 , and 0.010mm≤H4≤0.160mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0060] When 350mm 2 ≤S≤850mm 2 , and H4≥0.015mm, the thickness of the weak part is larger, and the weak part is not easy to crack in advance due to the change of the internal pressure of the battery monomer or external impact, which is beneficial to reduce the risk of the destruction of the weak part in advance and improve the service life of the battery monomer. When 350mm 2 ≤S≤850mm 2 , and H4≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery monomer is out of control, which is beneficial to improve the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0061] When 750mm 2 ≤S≤1250mm 2 , and H4≥0.020mm, the thickness of the weak part is larger, and the weak part is not easy to crack in advance due to the change of the internal pressure of the battery monomer or external impact, which is beneficial to reduce the risk of the destruction of the weak part in advance and improve the service life of the battery monomer. When 750mm 2 ≤S≤1250mm 2, and H4≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery cell is out of control, which is beneficial to improve the timeliness of the pressure relief mechanism. Therefore, when 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm, the service life of the battery cell and the timeliness of pressure relief can be considered.

[0062] When 1150mm 2 ≤S≤1650mm 2 , and H4≥0.025mm, the thickness of the weak part is large, and the weak part is not easy to be broken in advance due to the change of the pressure inside the battery cell or the impact of the outside world, which is beneficial to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell. When 1150mm 2 ≤S≤1650mm 2 , and H4≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery cell is out of control, which is beneficial to improve the timeliness of the pressure relief mechanism. Therefore, when 1550mm 2 ≤S≤2100mm 2 , and 0.025mm≤H4≤0.190mm, the service life of the battery cell and the timeliness of pressure relief can be considered.

[0063] When 1550mm 2 ≤S≤2100mm 2 , and H4≥0.030mm, the thickness of the weak part is large, and the weak part is not easy to be broken in advance due to the change of the pressure inside the battery cell or the impact of the outside world, which is beneficial to reduce the risk of the weak part being damaged in advance and improve the service life of the battery cell. When 1550mm 2 ≤S≤2100mm 2 , and H4≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened in time when the battery cell is out of control, which is beneficial to improve the timeliness of the pressure relief mechanism. Therefore, when 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H4≤0.200mm, the service life of the battery cell and the timeliness of pressure relief can be considered.

[0064] As an optional technical solution of the embodiment of the application, 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2and 0.025mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 and 0.030mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 and 0.035mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 and 0.040mm≤H4≤0.200mm.

[0065] In the above technical solutions, when 100mm 2 ≤S≤450mm 2 and H4≥0.020mm, the thickness of the weak part is larger, the weak part is less likely to be cracked in advance due to the change of the pressure inside the battery monomer or the external impact, and it is more conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery monomer. When 100mm 2 ≤S≤450mm 2 and H4≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened more timely when the battery monomer is out of control, and it is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 100mm 2 ≤S≤450mm 2 and 0.020mm≤H4≤0.160mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0066] When 350mm 2 ≤S≤850mm 2 and H4≥0.025mm, the thickness of the weak part is larger, the weak part is less likely to be cracked in advance due to the change of the pressure inside the battery monomer or the external impact, and it is more conducive to reducing the risk of the weak part being damaged in advance and improving the service life of the battery monomer. When 350mm 2 ≤S≤850mm 2 and H4≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened more timely when the battery monomer is out of control, and it is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 350mm 2 ≤S≤850mm 2 and 0.025mm≤H4≤0.170mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0067] When 750mm 2 ≤S≤1250mm 2, and H4 is greater than or equal to 0.030 mm, the thickness of the weak part is greater, the weak part is less likely to be cracked in advance due to the change of the pressure inside the battery monomer or the external impact, and it is more favorable to reduce the risk of the weak part being damaged in advance and improve the service life of the battery monomer. When 750 mm 2 ≤ S ≤ 1250 mm 2 , and H4 is less than or equal to 0.180 mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened more timely when the battery monomer is out of control, and it is more favorable to improve the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 750 mm 2 ≤ S ≤ 1250 mm 2 , and 0.030 mm ≤ H4 ≤ 0.180 mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0068] When 1150 mm 2 ≤ S ≤ 1650 mm 2 , and H4 is greater than or equal to 0.035 mm, the thickness of the weak part is greater, the weak part is less likely to be cracked in advance due to the change of the pressure inside the battery monomer or the external impact, and it is more favorable to reduce the risk of the weak part being damaged in advance and improve the service life of the battery monomer. When 1150 mm 2 ≤ S ≤ 1650 mm 2 , and H4 is less than or equal to 0.190 mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened more timely when the battery monomer is out of control, and it is more favorable to improve the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 1550 mm 2 ≤ S ≤ 2100 mm 2 , and 0.035 mm ≤ H4 ≤ 0.190 mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0069] When 1550 mm 2 ≤ S ≤ 2100 mm 2 , and H4 is greater than or equal to 0.040 mm, the thickness of the weak part is greater, the weak part is less likely to be cracked in advance due to the change of the pressure inside the battery monomer or the external impact, and it is more favorable to reduce the risk of the weak part being damaged in advance and improve the service life of the battery monomer. When 1550 mm 2 ≤ S ≤ 2100 mm 2 , and H4 is less than or equal to 0.200 mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can be opened more timely when the battery monomer is out of control, and it is more favorable to improve the timeliness of the pressure relief of the pressure relief mechanism. Therefore, when 1550 mm 2 ≤ S ≤ 2100 mm 2 , and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer can be considered.

[0070] As an optional technical solution of the embodiment of the present application, the connecting part is welded to the wall part.

[0071] In the above technical solution, the base material of the pressure relief mechanism and the wall part is iron, and the connecting part and the wall part are easier to weld, which is beneficial to reduce the phenomenon of welding cracks between the pressure relief mechanism and the wall part, thereby reducing the risk of liquid leakage of the battery monomer and improving the reliability of the battery monomer.

[0072] As an optional technical solution of the embodiment of the present application, the battery monomer further comprises a support structure, the support structure is fixed to the side of the wall part facing the electrode assembly, the pressure relief mechanism is located on the side of the support structure away from the electrode assembly, the connecting part is welded to the support structure, and the base material of the support structure is iron.

[0073] In the above technical solution, by arranging the support structure, when the connecting part and the wall part are welded, the support structure can reduce the risk that the laser passes through the gap between the connecting part and the wall part and acts on the electrode assembly, which is beneficial to improve the reliability of the battery monomer. In addition, the support structure can play a positioning role in the process of fixing the connection between the pressure relief mechanism and the wall part. The support structure can also be used to realize the connection and fixation between the pressure relief mechanism and the wall part, which can effectively improve the processing efficiency of the battery monomer. The support structure can also be used to support the pressure relief mechanism and the wall part, increase the structural strength and stability between the wall part and the pressure relief mechanism, and especially in the use process of the battery monomer, the support structure can also be used to resist deformation, reduce the cracking between the pressure relief mechanism and the wall part caused by the expansion of the battery monomer, and improve the stability of the battery monomer.

[0074] As an optional technical solution of the embodiment of the present application, the support structure and the wall part are fixed by welding or fixed by bonding.

[0075] In the above technical solution, when the support structure and the wall part are fixed by welding, the support structure and the wall part have high connection strength. When the support structure and the wall part are fixed by bonding, the connection between the support structure and the wall part is more convenient, which is beneficial to reduce the production cost.

[0076] As an optional technical solution of the embodiment of the present application, in the direction close to the electrode assembly, the pressure relief mechanism does not exceed the surface of the support structure facing the electrode assembly.

[0077] In the technical solution, by allowing the pressure relief mechanism to be no more than the surface of the support structure facing the electrode assembly in the direction close to the electrode assembly, on the one hand, the risk of interference between the pressure relief mechanism and other components in the battery monomer is reduced, and on the other hand, the risk of the pressure relief mechanism being subjected to external force applied by other components of the battery monomer is reduced, so that the weak part is not easy to crack in advance, the risk of the weak part being damaged in advance is reduced, and the service life of the battery monomer is improved.

[0078] As an optional technical solution of the embodiment of the application, the thickness H5 of the support structure satisfies 0.4mm≤H5≤1.5mm.

[0079] In the technical solution, when H5≥0.4mm, the thickness of the support structure is large, and the laser during welding is not easy to penetrate the support structure, so that the risk of the laser acting on the electrode assembly through the gap between the connecting part and the wall part is effectively reduced, and the reliability of the battery monomer is improved. When H5≤1.5mm, the thickness of the support structure is not too large, on the one hand, the occupation of the internal space of the battery monomer by the support structure is reduced, and the energy density of the battery monomer is improved. On the other hand, the material consumption of the support structure is reduced, and the manufacturing cost of the battery monomer is reduced. Therefore, when 0.4mm≤H5≤1.5mm, the reliability, energy density and manufacturing cost of the battery monomer can be considered.

[0080] As an optional technical solution of the embodiment of the application, 0.4mm≤H5≤0.8mm.

[0081] In the technical solution, when H5≥0.4mm, the thickness of the support structure is large, and the laser during welding is not easy to penetrate the support structure, so that the risk of the laser acting on the electrode assembly through the gap between the connecting part and the wall part is effectively reduced, and the reliability of the battery monomer is improved. When H5≤0.8mm, the thickness of the support structure is not too large, on the one hand, the occupation of the internal space of the battery monomer by the support structure is reduced, and the energy density of the battery monomer is improved. On the other hand, the material consumption of the support structure is reduced, and the manufacturing cost of the battery monomer is reduced. Therefore, when 0.4mm≤H5≤0.8mm, the reliability, energy density and manufacturing cost of the battery monomer can be considered.

[0082] As an optional technical solution of the embodiment of the application, the pressure relief mechanism, the wall part and the support structure are connected through the same welding seam.

[0083] In the technical solution, during welding, the pressure relief mechanism, the wall part and the support structure can be welded and connected at one time, which is simple and convenient to manufacture.

[0084] As an optional technical solution of the embodiment of the present application, the battery monomer further comprises a partition piece, the partition piece is arranged on the side of the wall part facing the electrode assembly, and the pressure relief mechanism at least partially protrudes from the surface of the wall part facing the electrode assembly in the direction close to the electrode assembly, and the partition piece protrudes from the surface of the pressure relief mechanism facing the electrode assembly.

[0085] In the above technical solution, the pressure relief mechanism at least partially protrudes from the surface of the wall part facing the electrode assembly in the direction close to the electrode assembly, by making the partition piece protrude from the surface of the pressure relief mechanism facing the electrode assembly in the direction close to the electrode assembly, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism and other components in the battery monomer, on the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism being subjected to external force applied by other components of the battery monomer, so that the weak part is not easy to crack in advance, which is beneficial to reduce the risk of the weak part being damaged in advance and improve the service life of the battery monomer.

[0086] As an optional technical solution of the embodiment of the present application, the partition piece comprises a fourth part and a fifth part arranged at intervals, and the pressure relief mechanism is located between the fourth part and the fifth part.

[0087] In the above technical solution, the partition piece comprises a fourth part and a fifth part arranged at intervals, by making the pressure relief mechanism located between the fourth part and the fifth part, on the one hand, the fourth part and the fifth part are not easy to affect the pressure relief mechanism to open the pressure relief, so that the battery monomer can timely relieve pressure. On the other hand, during manufacturing, the fourth part and the fifth part can be manufactured separately, and then the fourth part and the fifth part are arranged on both sides of the pressure relief mechanism, which is beneficial to simplify the manufacturing and reduce the assembly difficulty.

[0088] As an optional technical solution of the embodiment of the present application, the partition piece is provided with a avoiding opening for avoiding the pressure relief mechanism.

[0089] In the above technical solution, the pressure relief mechanism is avoided by setting the avoiding opening, which is beneficial to make the pressure relief mechanism open the pressure relief when the pressure inside the shell reaches the threshold value.

[0090] As an optional technical solution of the embodiment of the present application, the partition piece is provided with a containing groove with an opening facing the pressure relief mechanism, the containing groove is used for containing the pressure relief mechanism, the bottom of the containing groove is provided with a thinning area corresponding to the pressure relief mechanism, and the thickness of the thinning area is less than the thickness of other areas of the bottom of the containing groove.

[0091] In the technical solution, the accommodating groove is arranged to accommodate the pressure relief mechanism, which can reduce the risk of interference between the pressure relief mechanism and other components in the battery monomer, and reduce the risk of external force applied to the pressure relief mechanism by other components in the battery monomer, so that the weak part is less likely to be broken in advance, the risk of damage to the weak part is reduced, and the service life of the battery monomer is improved. When the pressure in the shell reaches the threshold value, the thinning area at the bottom of the accommodating groove can be opened to provide a path for the gas in the shell to flow to the pressure relief mechanism, thereby facilitating the opening of the pressure relief mechanism.

[0092] As an optional technical solution of the embodiment, in the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the wall portion farthest from the electrode assembly in the direction away from the electrode assembly.

[0093] In the technical solution, the pressure relief mechanism does not exceed the surface of the wall portion farthest from the electrode assembly in the thickness direction of the wall portion, which can reduce the occupation of the internal space of the battery, improve the energy density of the battery device, and reduce the risk of damage to the weak part, thereby improving the service life of the battery monomer.

[0094] As an optional technical solution of the embodiment, the battery monomer further comprises an electrode terminal arranged on the wall portion, and the electrode terminal at least partially protrudes from the wall portion in the direction away from the electrode assembly. In the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the electrode terminal farthest from the electrode assembly in the direction away from the electrode assembly.

[0095] In the technical solution, the pressure relief mechanism does not exceed the surface of the electrode terminal farthest from the electrode assembly in the thickness direction of the wall portion, which can reduce the occupation of the internal space of the battery, improve the energy density of the battery device, and reduce the risk of damage to the weak part, thereby improving the service life of the battery monomer.

[0096] As an optional technical solution of the embodiment, the weak part is in a closed ring shape, and the thickness of the weak part is uniform.

[0097] In the technical solution, the weak part is in a closed ring shape, and the thickness of the weak part is uniform. When the pressure in the shell reaches the threshold value, the pressure relief mechanism can be broken along the entire circumference of the weak part, so that the body part can be separated from the pressure relief mechanism, the body part is less likely to be suspended on the second part and block the gas eruption, the risk of high-temperature gas being injected into the adjacent battery monomer is reduced, and the reliability of the battery monomer is improved.

[0098] As an optional technical solution of the embodiment of the present application, the weak part is in the form of a closed ring, the weak part comprises a first weak section and a second weak section connected in a head-to-tail manner, the thickness of the second weak section is greater than the thickness of the first weak section, and the second weak section is located on one side of the weak part in the length direction of the wall part.

[0099] In the above technical solution, by arranging the second weak section, the strength of the pressure relief mechanism at the position of the second weak section is weakened, so that the body part is more likely to be turned over and opened under the action of the internal gas pressure of the battery monomer, which not only can improve the probability of opening of the body part, but also can improve the opening speed of the body part, realize rapid pressure relief, reduce the risk of explosion and fire of the battery monomer, and is beneficial to improving the reliability of the battery monomer. By arranging the second weak section on one side of the weak part in the length direction of the wall part, even if the body part is not completely opened when the battery monomer is relieved, the high-temperature gas sprayed out will diffuse towards the length direction of the wall part under the action of the body part, that is, the high-temperature gas sprayed out is not easy to be directed to the other battery monomer adjacent thereto, and is not easy to cause thermal runaway of the other battery monomer, which is beneficial to improving the reliability of the battery device.

[0100] As an optional technical solution of the embodiment of the present application, the weak part is in the form of an open ring, and the open end of the weak part is located on one side of the weak part in the length direction of the wall part.

[0101] In the above technical solution, by arranging the open end of the weak part on one side of the weak part in the length direction of the wall part, even if the body part is not completely opened when the battery monomer is relieved, the high-temperature gas sprayed out will diffuse towards the length direction of the wall part under the action of the body part, that is, the high-temperature gas sprayed out is not easy to be directed to the other battery monomer adjacent thereto, and is not easy to cause thermal runaway of the other battery monomer, which is beneficial to improving the reliability of the battery device.

[0102] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, and the bottom wall of the pressure relief groove forms the weak part.

[0103] In the above technical solution, the weak part is formed on the pressure relief mechanism by means of arranging the pressure relief groove on the pressure relief mechanism, and the pressure relief mechanism is cracked along at least part of the weak part when the battery monomer is relieved, which is simple and convenient, and has low cost.

[0104] As an optional technical solution of the embodiment of the present application, the pressure relief groove is formed by stamping.

[0105] In the technical solution, the pressure relief groove is formed by stamping, so that the thickness of the weak part is easier to control, the processing precision is higher, the battery monomer is beneficial to keep the burst pressure of the plurality of battery monomers consistent, and the battery monomer reliability is improved.

[0106] As an optional technical solution of the embodiment, the cross section of the pressure relief groove is trapezoidal or conical.

[0107] In the technical solution, when the cross section of the pressure relief groove is trapezoidal or conical, the body part is beneficial to quickly open the pressure relief when the battery monomer is in thermal runaway.

[0108] As an optional technical solution of the embodiment, along the width direction of the pressure relief groove, the pressure relief groove includes two groove side surfaces oppositely arranged, and the angle of the two groove side surfaces is b, and b satisfies 30°≤b≤90°, and optionally, 40°≤b≤80°.

[0109] In the technical solution, when b≥30°, the pressure relief groove can be conveniently stamped, the processing difficulty of the pressure relief groove is reduced, and the manufacturing cost of the battery monomer is reduced. When b≤90°, the extrusion is reduced. Therefore, when 30°≤b≤90°, the manufacturing cost of the battery monomer is reduced, and the extrusion is reduced.

[0110] When b≥40°, the pressure relief groove can be more conveniently stamped, the processing difficulty of the pressure relief groove is reduced, and the manufacturing cost of the battery monomer is further reduced. When b≤80°, the extrusion is further reduced. Therefore, when 40°≤b≤80°, the manufacturing cost of the battery monomer is reduced, and the extrusion is reduced.

[0111] In a second aspect, the embodiment also provides a pressure relief mechanism for a battery monomer. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak part, a body part, and a connecting part. The weak part is configured to be at least partially destroyed to release pressure when the pressure inside the battery monomer reaches a threshold value. The body part is located in an area surrounded by the weak part. The connecting part is located outside the weak part. A part of the body part close to the weak part is a first part. A part of the connecting part close to the weak part is a second part. At least one of the first part and the second part extends relative to the weak part along the thickness direction of the pressure relief mechanism.

[0112] In a third aspect, the embodiments of the present application further provide a manufacturing method of a pressure relief mechanism, the pressure relief mechanism being used in a battery cell, the manufacturing method comprising: step S100, providing a sheet, a base material of the sheet being iron; and step S200, processing a weak portion on the sheet, the weak portion being used to be at least partially destroyed to release pressure when the pressure inside the battery cell reaches a threshold value, a part of the sheet located in an area surrounded by the weak portion being a body portion, and a part of the sheet located outside the area surrounded by the weak portion being a connecting portion; wherein a part of the body portion close to the weak portion is a first part, a part of the connecting portion close to the weak portion is a second part, and at least one of the first part and the second part extends relative to the weak portion along a thickness direction of the sheet.

[0113] As an optional technical solution of the embodiments of the present application, before the step S200, the manufacturing method of the pressure relief mechanism further comprises: step S150, stamping the sheet to form a groove on the sheet; and the step S200 comprises: step S210, processing the weak portion on a groove bottom wall of the groove to make the second part extend relative to the weak portion along the thickness direction of the sheet.

[0114] In the above technical solution, by processing the groove on the sheet first and then processing the weak portion on the groove bottom surface, the second part can extend relative to the weak portion along the thickness direction of the sheet, which is simple and convenient.

[0115] As an optional technical solution of the embodiments of the present application, the step S200 comprises: step S220, stamping the sheet to process the weak portion on the sheet.

[0116] In the above technical solution, the weak portion is processed by stamping, which can more easily control the thickness of the weak portion, has higher processing precision, is beneficial to keeping the burst pressure of multiple battery cells consistent when the multiple battery cells are manufactured, and is beneficial to improving the reliability of the battery cell.

[0117] As an optional technical solution of the embodiments of the present application, in the step S220, a flow direction of the sheet is controlled to make the first part extend relative to the weak portion along the thickness direction of the sheet.

[0118] In the above technical solution, by controlling the flow direction of the sheet when the weak portion is formed by stamping, the first part can extend relative to the weak portion along the thickness direction of the sheet, which is simple and convenient.

[0119] In a fourth aspect, the embodiments of the present application further provide a battery device, the battery device comprising the battery cell described above.

[0120] In a fifth aspect, the embodiments of the present application further provide a power utilization device, which comprises the battery cell described above and is configured to provide electric energy for the power utilization device. BRIEF DESCRIPTION OF DRAWINGS

[0121] 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 considered as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0122] Fig. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application;

[0123] Fig. 2 is an exploded view of a battery device according to some embodiments of the present application;

[0124] Fig. 3 is a structural schematic diagram of a battery cell according to some embodiments of the present application;

[0125] Fig. 4 is an exploded view of a battery cell according to some embodiments of the present application;

[0126] Fig. 5 is a structural schematic diagram of a pressure relief mechanism according to some embodiments of the present application;

[0127] Fig. 6 is a top view of a pressure relief mechanism according to some embodiments of the present application;

[0128] Fig. 7 is a sectional view of the position A-A in Fig. 6;

[0129] Fig. 8 is an enlarged view of the position B in Fig. 7;

[0130] Fig. 9 is a sectional view of a pressure relief mechanism according to other embodiments of the present application;

[0131] Fig. 10 is a top view of a pressure relief mechanism according to yet other embodiments of the present application;

[0132] Fig. 11 is a sectional view of the position C-C in Fig. 10;

[0133] Fig. 12 is a top view of a pressure relief mechanism according to still other embodiments of the present application;

[0134] Fig. 13 is a sectional view of the position D-D in Fig. 12;

[0135] Fig. 14 is a sectional view of a pressure relief mechanism according to further other embodiments of the present application;

[0136] Fig. 15 is a sectional view of a pressure relief mechanism according to still further other embodiments of the present application;

[0137] Figure 16 is a cross-sectional view of a pressure relief mechanism provided in some other embodiments of this application;

[0138] Figure 17 is a schematic diagram showing the connection of the pressure relief mechanism, wall and support structure provided in some embodiments of this application;

[0139] Figure 18 is a schematic diagram showing the connection of the pressure relief mechanism, wall, support structure and partition provided in some embodiments of this application;

[0140] Figure 19 is a schematic diagram of the structure of the separator provided in some embodiments of this application;

[0141] Figure 20 is a structural schematic diagram of the separator provided in some other embodiments of this application;

[0142] Figure 21 is a cross-sectional view of a separator provided in some embodiments of this application;

[0143] Figure 22 is a cross-sectional view of a separator provided in some embodiments of this application;

[0144] Figure 23 is a schematic diagram of a structure in which electrode terminals are provided on the wall portion according to some embodiments of this application;

[0145] Figure 24 is a top view of a pressure relief mechanism provided in some further embodiments of this application;

[0146] Figure 25 is a cross-sectional view of the EE location in Figure 24;

[0147] Figure 26 is a top view of a pressure relief mechanism provided in some embodiments of this application;

[0148] Figure 27 is a schematic block diagram of a method for manufacturing a pressure relief mechanism according to some embodiments of this application;

[0149] Figure 28 is a schematic block diagram of a method for manufacturing a pressure relief mechanism according to other embodiments of this application;

[0150] Figure 29 is a schematic block diagram of a method for manufacturing a pressure relief mechanism according to some embodiments of this application.

[0151] Icon: 10 - case; 11 - first case body; 12 - second case body; 20 - battery cell; 21 - housing; 211 - shell; 212 - end cover; 213 - wall portion; 2131 - pressure relief hole; 23 - electrode assembly; 231 - main body; 232 - tab; 24 - pressure relief mechanism; 241 - connecting portion; 2411 - second portion; 2412 - third portion; 2421 - weak portion; 24212 - first weak section; 24213 - second weak section; 24212a - first section; 24212b - second section; 24212c - third section; 2422 - body portion; 24221 - first portion; 245 - pressure relief groove; 2451 - groove bottom surface; 2452 - groove side surface; 2453 - round corner; 246 - first surface; 25 - electrode terminal; 26 - protection member; 27 - insulation member; 28 - support structure; 281 - weld; 29 - partition member; 291 - fourth portion; 292 - fifth portion; 293 - avoidance opening; 294 - accommodation groove; 2941 - thinning area; 30 - pressure relief mechanism manufacturing method; 100 - battery device; 200 - controller; 300 - motor; 1000 - vehicle. DETAILED DESCRIPTION

[0152] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all 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 the present application.

[0153] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, rather than to describe a particular order or primary and secondary relationship.

[0154] In the present application, the phrase "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments.

[0155] In the description of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mount", "connect", "connection", "attach" should be broadly interpreted, for example, can be fixedly connected, or can be detachably connected, or integrally connected, can be directly connected, or indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0156] The term "and / or" in the present application is only to describe the association relationship of the associated objects, which means that there can be three 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 present application generally represents that the front and rear associated objects have an "or" relationship.

[0157] In the embodiments of the present 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 present 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 present application.

[0158] "Multiple" appearing in the present application means two or more (including two).

[0159] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0160] The battery cell can be 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, etc. The embodiments of the present application are not limited thereto.

[0161] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can prevent the positive and negative electrodes from short-circuiting to some extent, and at the same time allow the active ions to pass through.

[0162] 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 arranged on at least one surface of the positive electrode current collector.

[0163] As an example, the positive electrode current collector has two opposite surfaces in its own thickness direction, and the positive electrode active material is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0164] As an example, the positive electrode current collector can employ a metal foil or a composite current collector. For example, as the metal foil, aluminum subjected to silver plating on the surface, stainless steel subjected to silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The composite current collector can include a high molecular 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, or the like) on a high molecular material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0165] As an 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 battery positive electrode active material can also be used. These positive electrode active materials can be used alone only in one kind, or two or more kinds can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to simply as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), 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, lithium cobalt oxide (such as LiCo02), lithium nickel oxide (such as LiNi02), lithium manganese oxide (such as LiMn02, LiMn204), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to simply as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to simply as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to simply as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to simply as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to simply as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and modified compounds thereof, etc.

[0166] In some embodiments, the positive electrode can employ a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. When the foamed metal is employed as the positive electrode, the foamed metal surface can be free of the positive electrode active material, or can be provided with the positive electrode active material. As an example, the foamed metal can be filled or / and deposited with a lithium source material, potassium metal, or sodium metal. The lithium source material can be lithium metal and / or a lithium-rich material.

[0167] In some embodiments, the negative electrode can be a negative electrode tab, which can include a negative electrode current collector.

[0168] As an example, the negative electrode current collector can employ a metal foil, a foamed metal, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, nickel, or titanium, etc. can be employed. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. 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 (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0169] As an example, the negative electrode tab can include a negative electrode current collector and a negative electrode active material provided on at least one surface of the negative electrode current collector.

[0170] 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 opposite surfaces of the negative electrode current collector.

[0171] As an example, the negative electrode active material can employ a negative electrode active material known in the art for use in a battery cell. 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 battery negative electrode active material can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0172] 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.

[0173] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0174] In some embodiments, the separator is a separator film. The separator film can be of various types, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0175] 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.

[0176] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode and the negative electrode, and functions to transport ions and separate the positive and negative electrodes.

[0177] 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.

[0178] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoroboric oxalate, lithium bisoxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorodioxalate phosphate.

[0179] 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, butanedisulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent 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.

[0180] Among them, the gel electrolyte includes a polymer as a skeleton network of the electrolyte, in combination with an ionic liquid-lithium salt.

[0181] Among them, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0182] 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, a cellulose, or the like.

[0183] 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.

[0184] As an example, the composite solid-state electrolyte is formed by adding an inorganic solid-state electrolyte filler to a polymer solid-state electrolyte.

[0185] 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.

[0186] In some embodiments, the electrode assembly is in a stack structure.

[0187] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be alternately stacked.

[0188] 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.

[0189] 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.

[0190] As an example, a plurality of separators can be provided, and each of the separators is provided between any adjacent positive electrode sheet or negative electrode sheet.

[0191] As an example, the separators can be continuously provided and provided between any adjacent positive electrode sheet or negative electrode sheet by folding or winding.

[0192] In some embodiments, the electrode assembly can have a cylindrical shape, a flat shape, or a multi-prism shape, or the like.

[0193] In some embodiments, the electrode assembly is provided with a tab. The tab can guide current out of the electrode assembly. The tab includes a positive tab and a negative tab.

[0194] In some embodiments, the battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, or the like.

[0195] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, the housing can serve to protect the electrode assembly and to some extent prevent leakage of electrolyte and the like. When the housing is a non-sealed structure, the housing can serve to protect the electrode assembly, and a sealing bag can be further included between the housing and the electrode assembly for encapsulating the electrode assembly, electrolyte, and the like. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum plastic film.

[0196] 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, and the prismatic battery cell includes, but is not limited to, a square battery cell, a blade battery cell, a multi-prismatic battery cell, for example, a hexagonal battery cell, and the like.

[0197] The battery device referred to in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0198] In some embodiments, the battery device can be a battery module, and when there are a plurality of battery cells, the plurality of battery cells are arranged and fixed to form a battery module.

[0199] In some embodiments, the battery device can be a battery pack, and the battery pack includes a box and a battery cell or a battery module accommodated in the box.

[0200] In some embodiments, the box can be part of a chassis structure of a vehicle. For example, part of the box can be at least part of a floor of the vehicle, or part of the box can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0201] In some embodiments, the battery device can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, and the like.

[0202] At present, from the development of market situation, the application of batteries is more and more extensive. Batteries are not only applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power stations, but also widely applied to electric bicycles, electric motorcycles, electric vehicles, and other electric vehicles, as well as military equipment, aerospace, and other fields. With the continuous expansion of the application field of batteries, the demand for the market is also increasing.

[0203] Batteries are widely used in the field of new energy, such as electric vehicles, new energy vehicles, and the like. New energy vehicles and electric vehicles have become a new trend in the development of the automobile industry. The development of battery technology needs to consider many design factors, such as energy density, discharge capacity, charge-discharge rate, and other performance parameters. In addition, the reliability of the battery also needs to be considered. However, the reliability of the battery is poor at present.

[0204] For the battery monomer, in order to improve the reliability of the battery monomer, the prior art is to provide a pressure relief mechanism on the battery monomer, and the pressure relief mechanism is provided with a weak part. When the internal pressure of the battery monomer reaches the burst pressure, the weak part is cracked to release the internal pressure of the battery monomer, thereby reducing the risk of explosion and fire of the battery monomer.

[0205] However, at present, when a plurality of battery monomers are manufactured, the burst pressures of the plurality of battery monomers are quite different. Some battery monomers have the weak part cracked before the internal pressure reaches the burst pressure, and some battery monomers still have the weak part not cracked after the internal pressure exceeds the burst pressure, so that the risk of explosion and fire of the battery monomer is increased, resulting in poor reliability of the battery monomer.

[0206] Therefore, the embodiment of the present application provides a battery monomer. The battery monomer comprises a shell, an electrode assembly and a pressure relief mechanism. The shell has a wall part, and the base material of the wall part is iron. The electrode assembly is contained in the shell. The base material of the pressure relief mechanism is iron. The pressure relief mechanism comprises a weak part, a body part and a connecting part. The weak part is configured to be at least partially destroyed to release pressure when the pressure inside the shell reaches a threshold value. The body part is located in an area surrounded by the weak part. The connecting part is located outside the weak part and connected to the wall part. A part of the body part close to the weak part is a first part, and a part of the connecting part close to the weak part is a second part. At least one of the first part and the second part extends relative to the weak part in a direction close to or away from the electrode assembly.

[0207] By extending at least one of the first part and the second part relative to the weak part in a direction close to or away from the electrode assembly, the flow of material is facilitated when the weak part is formed by stamping, which is beneficial to improve the stress of the weak part, so that the formed weak part has good structural stability and is not prone to have a concave-convex wavy structure. This is beneficial to keep the burst pressures of the plurality of battery monomers consistent when the plurality of battery monomers are manufactured, and is beneficial to improve the reliability of the battery monomer. Furthermore, when the battery monomer expands, the wall part is deformed under stress, and at least one of the first part and the second part extending relative to the weak part can be stretched under the action of external force, thereby reducing the pulling of the weak part by the external force and reducing the risk of the weak part being damaged in advance, which is beneficial to improve the service life and reliability of the battery monomer.

[0208] The technical solutions described in the embodiments of the present application are applicable to battery devices and electric devices using battery devices.

[0209] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, etc. The electric toy includes a stationary or mobile electric toy, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, which can include but is not limited to a power drill, a power grinder, a power wrench, a power screwdriver, a power hammer, an impact power drill, a concrete vibrator, and a power planer, etc.

[0210] The following embodiments are described by taking the electric device as a vehicle for convenience of illustration.

[0211] Please refer to FIG. 1, which is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile, which can be a pure electric vehicle, a hybrid electric vehicle, or a range extended vehicle, etc. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, the head, or the 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 an operating power source of the vehicle 1000. 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, to meet the working power demand of the vehicle 1000 during starting, navigation, and driving.

[0212] In some embodiments of the present application, the battery device 100 can not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0213] Please refer to FIG. 2, which is an exploded view of the battery device 100 according to some embodiments of the present application. The battery device 100 includes a box 10 and a battery cell 20, which is accommodated in the box 10. The box 10 is used to provide an accommodation space for the battery cell 20, and the box 10 can have various structures. In some embodiments, the box 10 can include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 are overlapped with each other, and the first box body 11 and the second box body 12 together define an accommodation space for accommodating the battery cell 20. The second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-shaped structure, which is overlapped with the open side of the second box body 12 to make the first box body 11 and the second box body 12 together define the accommodation space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 is overlapped with the open side of the second box body 12. Of course, the box 10 formed by the first box body 11 and the second box body 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0214] In the battery device 100, the battery cell 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. The mixed connection means that there are both series connection and parallel connection among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and then the whole of the multiple battery cells 20 is accommodated in the box 10; of course, the battery device 100 can also be that the multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is accommodated in the box 10. The battery device 100 can also include other structures, for example, the battery device 100 can also include a current collecting component for realizing the electrical connection between the multiple battery cells 20.

[0215] Each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can have a cylindrical shape, a flat shape, a cuboid shape, or other shapes, etc.

[0216] Please refer to FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8. FIG. 3 is a structural schematic diagram of a battery cell 20 according to some embodiments of the present application. FIG. 4 is an exploded view of the battery cell 20 according to some embodiments of the present application. FIG. 5 is a structural schematic diagram of a pressure relief mechanism 24 according to some embodiments of the present application. FIG. 6 is a top view of the pressure relief mechanism 24 according to some embodiments of the present application. FIG. 7 is a sectional view of the position A-A in FIG. 6. FIG. 8 is an enlarged view of the position B in FIG. 7. According to some embodiments of the present application, a battery cell 20 is provided, which includes a housing 21, an electrode assembly 23 and a pressure relief mechanism 24. The housing 21 has a wall portion 213, the base material of which is iron, and the electrode assembly 23 is accommodated in the housing 21. The pressure relief mechanism 24 has a base material of iron. The pressure relief mechanism 24 includes a weak portion 2421, a body portion 2422 and a connecting portion 241. The weak portion 2421 is configured to be at least partially destroyed to release pressure when the pressure inside the housing 21 reaches a threshold value. The body portion 2422 is located in the area surrounded by the weak portion 2421. The connecting portion 241 is located outside the weak portion 2421 and is connected to the wall portion 213. The portion of the body portion 2422 close to the weak portion 2421 is a first portion 24221. The portion of the connecting portion 241 close to the weak portion 2421 is a second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23.

[0217] The battery cell 20 refers to the smallest unit that constitutes the battery device 100.

[0218] The housing 21 includes a casing 211 and an end cover 212. The casing 211 has an open-ended accommodation space for accommodating the electrode assembly 23. The end cover 212 is connected to the casing 211 and closes the opening.

[0219] The end cover 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 212 can be adapted to the shape of the shell 211 to fit the shell 211. Optionally, the end cover 212 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cover 212 is not easily deformed when subjected to extrusion collision, so that the battery cell 20 can have higher structural strength and reliability performance can also be improved. The material of the end cover 212 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The end cover 212 is also provided with an electrode terminal 25, which is used to electrically connect with the tab 232 of the electrode assembly 23 to input or output the electrical energy of the battery cell 20. The electrode terminal 25 and the tab 232 can be directly connected, for example, the electrode terminal 25 and the tab 232 are directly welded. The electrode terminal 25 and the tab 232 can also be indirectly connected, for example, the electrode terminal 25 and the tab 232 are indirectly connected through a current collecting member. The battery cell 20 also includes an insulating member 27, which is arranged on the inner side of the end cover 212, and the insulating member 27 can be used to isolate the electrical connection components in the shell 211 from the end cover 212 to reduce the risk of short circuit. Exemplarily, the insulating member can be plastic, rubber, etc.

[0220] The shell 211 is a component for fitting the end cover 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, the electrolyte and other components. The shell 211 and the end cover 212 can be independent components, and an opening can be provided on the shell 211, and the end cover 212 is covered on the opening to form the internal environment of the battery cell 20. Without limitation, the end cover 212 and the shell 211 can also be integrated, specifically, the end cover 212 and the shell 211 can form a common joint surface before other components enter the shell, and when it is necessary to seal the inside of the shell 211, the end cover 212 is covered on the shell 211. The shell 211 can be various shapes and various sizes, such as cuboid, cylinder, hexagonal prism, etc. Specifically, the shape of the shell 211 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 211 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0221] The electrode assembly 23 is a component in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 can be contained within the case 211. The electrode assembly 23 is mainly formed by winding or layering a positive electrode tab and a negative electrode tab, and an insulating film is generally provided between the positive electrode tab and the negative electrode tab. The positive electrode tab and the negative electrode tab have portions with active materials that constitute a main body 231 of the electrode assembly 23, and portions without active materials that each constitute a tab 232. The positive tab and the negative tab can be located together at one end of the main body 231 or at opposite ends of the main body 231. During charging and discharging of the battery cell 20, the positive active material and the negative active material react with an electrolyte.

[0222] The wall portion 213 can be an end cover 212 of the case 21 or a wall of the case 211 of the case 21. Exemplarily, in FIGS. 3 and 4, the wall portion 213 is the end cover 212. In other embodiments, the wall portion 213 is a bottom wall of the case 211 that is provided opposite to the end cover 212. In yet other embodiments, the wall portion 213 can also be a side wall of the case 211 that is adjacent to the end cover 212 and connected thereto.

[0223] The "base material of the wall portion 213 is iron" means that the material with the largest mass percentage in the material of the wall portion 213 is iron. For example, the material of the wall portion 213 can be carbon steel or stainless steel.

[0224] The pressure relief mechanism 24 is a component for opening when the internal pressure or temperature of the battery cell 20 reaches the burst pressure, to release the internal pressure of the battery cell 20. The pressure relief mechanism 24 is a component mounted on the wall portion 213, and the pressure relief mechanism 24 is provided separately from the wall portion 213 and connected thereto. When manufactured, a pressure relief hole 2131 is provided on the wall portion 213, and the pressure relief mechanism 24 and the wall portion 213 are provided separately and finally connected together, so that the pressure relief mechanism 24 covers the pressure relief hole 2131. For example, the pressure relief mechanism 24 can be welded to the wall portion 213. The pressure relief mechanism 24 can be a rupture disc mounted on the wall portion 213. The wall of the case 21 that is the wall portion 213 can be determined by the position at which the pressure relief mechanism 24 is provided. For example, when the pressure relief mechanism 24 is provided on the end cover 212, the end cover 212 is the wall portion 213. When the pressure relief mechanism 24 is provided on the bottom wall of the case 211, the bottom wall is the wall portion 213. When the pressure relief mechanism 24 is provided on the side wall of the case 211, the side wall is the wall portion 213.

[0225] The "base material of the pressure relief mechanism 24 is iron" means that the material with the largest mass percentage in the material of the pressure relief mechanism 24 is iron. For example, the material of the pressure relief mechanism 24 can be carbon steel or stainless steel.

[0226] The weak portion 2421 functions as a pressure relief portion for enabling the pressure relief mechanism 24 to be broken along at least a portion of the weak portion 2421 to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value. In some embodiments, the strength of the pressure relief mechanism 24 at the position of the weak portion 2421 can be lower than the strength of the pressure relief mechanism 24 at other positions, so that the weak portion 2421 can be broken by the internal pressure to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches the predetermined value. In other embodiments, the melting point of the pressure relief mechanism 24 at the position of the weak portion 2421 can be lower than the melting point of the pressure relief mechanism 24 at other positions. Thus, the weak portion 2421 can be broken by the high temperature to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches the predetermined value.

[0227] The weak portion 2421 can have a ring shape, for example, the weak portion 2421 can have a circular ring shape or an elliptical ring shape. The weak portion 2421 can also have a non-ring shape, for example, the weak portion 2421 can have a C shape or a U shape.

[0228] The body portion 2422 is a portion of the pressure relief mechanism 24 located within the area surrounded by the weak portion 2421. The connecting portion 241 is a portion of the pressure relief mechanism 24 located outside the area surrounded by the weak portion 2421, and is used to connect with the wall portion 213. The area surrounded by the weak portion 2421 is an area in which the pressure relief mechanism 24 forms an opening after the weak portion 2421 is broken by the gas inside the case 21. In the case where the weak portion 2421 has a ring shape, the area surrounded by the weak portion 2421 is an area within the ring shape. In the case where the weak portion 2421 has a non-ring shape, the area surrounded by the weak portion 2421 is an area within the ring shape formed by the weak portion 2421 itself and the line connecting the two ends of the weak portion 2421.

[0229] The first portion 24221 is a portion of the body portion 2422 located close to the weak portion 2421, in other words, the boundary of the first portion 24221 overlaps with the inner boundary of the weak portion 2421.

[0230] The second portion 2411 is a portion of the connecting portion 241 located close to the weak portion 2421, in other words, the boundary of the second portion 2411 overlaps with the outer boundary of the weak portion 2421.

[0231] Please refer to FIG. 4 and FIG. 7, the thickness direction of the wall portion 213 is the X direction shown in the figures. In the figures, the direction along the thickness direction of the wall portion 213 downward is the direction close to the electrode assembly 23, and the direction along the thickness direction of the wall portion 213 upward is the direction away from the electrode assembly 23.

[0232] The "extending at least one of the first portion 24221 and the second portion 2411 relative to the weakened portion 2421 in a direction close to or away from the electrode assembly 23" includes the following several scenarios: only the first portion 24221 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23, only the first portion 24221 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23, only the second portion 2411 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23, only the second portion 2411 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23 and the second portion 2411 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23, the first portion 24221 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23 and the second portion 2411 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 and the second portion 2411 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23, and the first portion 24221 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 and the second portion 2411 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23.

[0233] By extending at least one of the first portion 24221 and the second portion 2411 relative to the weakened portion 2421 in a direction close to or away from the electrode assembly 23, the flow of material is facilitated when the weakened portion 2421 is formed by stamping, which is conducive to improving the stress of the weakened portion 2421, so that the formed weakened portion 2421 has good structural stability and is less likely to have a concave-convex wavy structure, which is conducive to keeping the burst pressure of the plurality of battery monomers 20 consistent when the plurality of battery monomers 20 are manufactured, and is conducive to improving the reliability of the battery monomer 20. Furthermore, when the battery monomer 20 expands, the wall portion 213 deforms under stress, and at least one of the first portion 24221 and the second portion 2411 that extends relative to the weakened portion 2421 can be stretched under external force, thereby reducing the pulling of the weakened portion 2421 by the external force and reducing the risk of the weakened portion 2421 being damaged prematurely, which is conducive to improving the service life and reliability of the battery monomer 20.

[0234] In some embodiments, the difference between the surface roughness of the first portion 24221 and the surface roughness of the weakened portion 2421 is less than or equal to Ra0.3, and / or the difference between the surface roughness of the second portion 2411 and the surface roughness of the weakened portion 2421 is less than or equal to Ra0.3.

[0235] Surface roughness refers to the unevenness of a machined surface having small pitch and tiny peaks and valleys. The distance between two peaks or two valleys (pitch) is very small (below 1 mm), which belongs to micro-geometric error. The smaller the surface roughness, the smoother the surface.

[0236] The difference between the surface roughness of the first part 24221 and the surface roughness of the weak portion 2421 is less than or equal to Ra 0.3, that is, the surface roughness of the first part 24221 and the surface roughness of the weak portion 2421 are substantially the same.

[0237] The difference between the surface roughness of the second part 2411 and the surface roughness of the weak portion 2421 is less than or equal to Ra 0.3, that is, the surface roughness of the second part 2411 and the surface roughness of the weak portion 2421 are substantially the same.

[0238] The surface roughness of the first part 24221 and the surface roughness of the weak portion 2421 are substantially the same, and the surface roughness of the second part 2411 and the surface roughness of the weak portion 2421 are substantially the same, so that the weak portion 2421 can be formed by stamping, and the roughness of the weak portion 2421 is lower, so that the thickness consistency of the weak portion 2421 at different positions is higher, which is more conducive to improving the consistency of the burst pressure.

[0239] Optionally, the surface roughness of the weak portion 2421, the surface roughness of the first part 24221 and the surface roughness of the second part 2411 are the same.

[0240] The surface roughness of the first part 24221 and the surface roughness of the weak portion 2421 are substantially the same, and the surface roughness of the second part 2411 and the surface roughness of the weak portion 2421 are substantially the same, so that the weak portion 2421 can be formed by stamping, and the roughness of the weak portion 2421 is lower, so that the thickness consistency of the weak portion 2421 at different positions is higher, which is more conducive to improving the consistency of the burst pressure.

[0241] Please refer to FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8, in some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, and the bottom wall of the pressure relief groove 245 forms a weak portion 2421. The groove side surface 2452 of the pressure relief groove 245 and the groove bottom surface 2451 of the pressure relief groove 245 are transitioned by a round corner 2453. And / or the pressure relief mechanism 24 includes a first surface 246, the pressure relief groove 245 is arranged on the first surface 246, and the groove side surface 2452 of the pressure relief groove 245 and the first surface 246 are transitioned by a round corner 2453.

[0242] The pressure relief mechanism 24 has a first surface 246 and a second surface 247 arranged opposite to each other in the thickness direction of the wall portion 213. One of the first surface 246 and the second surface 247 faces the electrode assembly 23, and the other of the first surface 246 and the second surface 247 is away from the electrode assembly 23. The pressure relief groove 245 is arranged on the first surface 246, that is, the pressure relief groove 245 is recessed from the first surface 246 toward the second surface. The weak portion 2421 is a portion between the groove bottom surface 2451 of the pressure relief groove 245 and the second surface.

[0243] The pressure relief groove 245 can be formed in various ways, such as punch forming, cold heading, and the like. For example, the pressure relief groove 245 is formed by punch forming. The pressure relief groove 245 is formed on the pressure relief mechanism 24 in the thickness direction of the wall portion 213.

[0244] The pressure relief groove 245 is formed by punch forming or cold heading. The groove wall of the pressure relief groove 245 is cold-worked (the crystal grain arrangement is changed, the crystal lattice is distorted, the metal plasticity is reduced, and the material hardness is increased), so that the resistance to external impact is enhanced, and the pressure relief mechanism 24 is not easily damaged by external impact. In this way, the risk of liquid leakage of the pressure relief mechanism 24 is reduced.

[0245] The groove side surface 2452 of the pressure relief groove 245 and the groove bottom surface 2451 of the pressure relief groove 245 are rounded to transition smoothly.

[0246] The groove side surface 2452 of the pressure relief groove 245 and the first surface 246 are rounded to transition smoothly.

[0247] The weak portion 2421 is formed on the pressure relief mechanism 24 by opening the pressure relief groove 245 on the pressure relief mechanism 24. When the battery monomer 20 is relieved, the pressure relief mechanism 24 is cracked along at least part of the weak portion 2421, which is simple, convenient, and low in cost. The groove side surface 2452 of the pressure relief groove 245 and the groove bottom surface 2451 of the pressure relief groove 245 are transitioned by the round corner 2453, which is beneficial to reduce stress concentration and improve the consistency of the burst pressure. The groove side surface 2452 of the pressure relief groove 245 and the first surface 246 are transitioned by the round corner 2453, which is beneficial to reduce stress concentration and improve the consistency of the burst pressure.

[0248] In some embodiments, the material of the wall portion 213 includes at least one of stainless steel and carbon steel. The material of the pressure relief mechanism 24 includes at least one of stainless steel and carbon steel.

[0249] The material of the wall portion 213 can be carbon steel or stainless steel, and the carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0250] It should be noted that the material of the wall portion 213 includes at least one of stainless steel and carbon steel, and if the wall portion 213 is the end cover 212 of the shell 21, the material of the end cover 212 includes at least one of stainless steel and carbon steel; if the wall portion 213 is one wall of the shell 211, the material of the shell 211 includes at least one of stainless steel and carbon steel.

[0251] In this embodiment, by setting the material of the wall portion 213 to include at least one of stainless steel and carbon steel, since steel has the characteristic of high strength, the wall portion 213 made of steel has better strength, so that under the condition that the burst pressure of the battery monomer 20 is certain, the wall portion 213 can be made thinner, which is beneficial to save the space occupied by the wall portion 213.

[0252] The material of the pressure relief mechanism 24 can be carbon steel or stainless steel, etc., and the carbon steel can be low carbon steel, medium carbon steel or high carbon steel. For example, the material of the pressure relief mechanism 24 can be 304 stainless steel, 305 stainless steel, 316 stainless steel, etc.

[0253] Stainless steel and carbon steel have high strength, which can effectively improve the structural strength of the wall portion 213 and the pressure relief mechanism 24, reduce the risk of deformation of the wall portion 213 and the pressure relief mechanism 24 under stress, and is beneficial to reduce the risk of early valve pressure relief of the pressure relief mechanism 24, and is beneficial to improve the service life and reliability of the battery monomer 20. In addition, using at least one of stainless steel and carbon steel to manufacture the wall portion 213 can appropriately reduce the thickness of the wall portion 213, which is beneficial to increase the internal space of the shell 21 under the condition of the same volume, thereby increasing the energy density.

[0254] Optionally, the material of the wall portion 213 includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel. The material of the pressure relief mechanism 24 includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel.

[0255] 304 stainless steel, 305 stainless steel and 316L stainless steel have the advantages of corrosion resistance, high temperature resistance and good processing performance, and the wall portion 213 and the pressure relief mechanism 24 made of 304 stainless steel, 305 stainless steel or 316L stainless steel have high strength, which can reduce the risk of deformation of the wall portion 213 and the pressure relief mechanism 24 under stress, is beneficial to reduce the risk of early valve pressure relief of the pressure relief mechanism 24, is beneficial to improve the service life and reliability of the battery monomer 20, and is beneficial to improve the consistency of the burst pressure of the plurality of battery monomers 20.

[0256] Please refer to FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8, in some embodiments, the thickness of the body portion 2422 is H1, which satisfies: 0.05mm≤H1≤0.5mm. And / or the thickness of the connecting portion 241 is H2, which satisfies: 0.05mm≤H2≤0.5mm.

[0257] H1 represents the thickness of the body portion 2422. When measuring, the measurement can be taken along the direction perpendicular to the surface of the body portion 2422 to obtain the thickness of the body portion 2422. In addition, multiple measurements can be taken and the average value is taken as H1.

[0258] The thickness of the body portion 2422 can be: H1=0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc.

[0259] When H1≥0.05mm, the thickness of the body portion 2422 is large, the body portion 2422 has high structural strength, which can reduce the risk of deformation of the body portion 2422 under stress, and is beneficial to improve the service life and reliability of the battery monomer 20. When H1≤0.5mm, the thickness of the body portion 2422 is not too large, which is beneficial to control the manufacturing cost of the battery monomer 20. Therefore, when 0.05mm≤H1≤0.5mm, the service life, reliability and manufacturing cost of the battery monomer 20 can be considered.

[0260] H2 represents the thickness of the connecting portion 241. When measuring, the measurement can be taken along the direction perpendicular to the surface of the connecting portion 241 to obtain the thickness of the connecting portion 241. In addition, multiple measurements can be taken and the average value is taken as H2.

[0261] The thickness of the connecting portion 241 can be: H2=0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc.

[0262] When H2≥0.05mm, the thickness of the connecting portion 241 is large, the connecting portion 241 has high structural strength, which can reduce the risk of deformation of the connecting portion 241 under stress, and is beneficial to improve the service life and reliability of the battery monomer 20. When H2≤0.5mm, the thickness of the connecting portion 241 is not too large, which is beneficial to control the manufacturing cost of the battery monomer 20. Therefore, when 0.05mm≤H2≤0.5mm, the service life, reliability and manufacturing cost of the battery monomer 20 can be considered.

[0263] In some embodiments, an extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 ranges from [0.2mm, 7mm].

[0264] The extension height of the first portion 24221 extending relative to the weakened portion 2421 is a distance from an end of the first portion 24221 farthest from the weakened portion 2421 to the weakened portion 2421 along a thickness direction of the wall portion 213.

[0265] The extension height of the second portion 2411 extending relative to the weakened portion 2421 is a distance from an end of the second portion 2411 farthest from the weakened portion 2421 to the weakened portion 2421 along a thickness direction of the wall portion 213.

[0266] The extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is greater than or equal to 0.2mm and less than or equal to 7mm.

[0267] The extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 can be 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, etc.

[0268] When the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is greater than or equal to 0.2 mm, the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is large, which facilitates the flow of material when the weakened portion 2421 is formed by stamping, is conducive to improving the stress of the weakened portion 2421, and makes the structure of the formed weakened portion 2421 have good stability. When the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is less than or equal to 7 mm, the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is not too large, on the one hand, which is conducive to reducing the occupation of the internal space of the battery device 100 or the battery monomer 20 and improving the energy density of the battery device 100 or the battery monomer 20, and on the other hand, which is conducive to reducing the risk of interference with other components. Therefore, when the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is in the range of [0.2 mm, 7 mm], the service life and energy density of the battery monomer 20 can be considered, and the risk of interference with other components can be reduced.

[0269] Optionally, the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is in the range of [0.3 mm, 5 mm].

[0270] The extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 can be 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, etc.

[0271] When the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is greater than or equal to 0.3 mm, the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is greater, which facilitates the flow of material when the weakened portion 2421 is formed by stamping, and is beneficial to improve the stress of the weakened portion 2421, so that the formed weakened portion 2421 has good structural stability. When the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is less than or equal to 5 mm, the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is not too large, on the one hand, which is beneficial to reduce the occupation of the internal space of the battery device 100 or the battery monomer 20, and improve the energy density of the battery device 100 or the battery monomer 20, on the other hand, which is beneficial to reduce the risk of interference with other components. Therefore, when the extension height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weakened portion 2421 is in the range of [0.3 mm, 5 mm], the service life and energy density of the battery monomer 20 can be better balanced, and the risk of interference with other components can be reduced.

[0272] Please refer to 6, 7, 8, 9, 10 and 11, FIG. 9 is a cross-sectional view of the pressure relief mechanism 24 provided by some embodiments of the application. FIG. 10 is a top view of the pressure relief mechanism 24 provided by some embodiments of the application. FIG. 11 is a cross-sectional view of the C-C position in FIG. 10. In some embodiments, the first portion 24221 is at least partially extended relative to the weakened portion 2421 in the direction close to or away from the electrode assembly 23.

[0273] The first portion 24221 can be at least partially extended relative to the weakened portion 2421 in the direction close to the electrode assembly 23. The first portion 24221 can also be at least partially extended relative to the weakened portion 2421 in the direction away from the electrode assembly 23.

[0274] Please refer to FIG. 6 and FIG. 7, in the embodiments shown in FIG. 6 and FIG. 7, the first portion 24221 is at least partially extended relative to the weakened portion 2421 in the direction away from the electrode assembly 23, and the second portion 2411 is extended relative to the weakened portion 2421 in the direction away from the electrode assembly 23.

[0275] Please refer to FIG. 10 and FIG. 11, in the embodiments shown in FIG. 10 and FIG. 11, the first portion 24221 is at least partially extended relative to the weakened portion 2421 in the direction away from the electrode assembly 23, and the second portion 2411 is a straight portion.

[0276] In addition, the first portion 24221 can extend in the direction of approaching or moving away from the electrode assembly 23 relative to the weak portion 2421 in its entirety, or only a part of the first portion 24221 can extend in the direction of approaching or moving away from the electrode assembly 23 relative to the weak portion 2421.

[0277] By extending the first portion 24221 in the direction of approaching or moving away from the electrode assembly 23 relative to the weak portion 2421 at least partially, not only is it convenient for the flow of material when the weak portion 2421 is stamped, but it is also beneficial for improving the stress of the weak portion 2421, and it is also possible to increase the contact area with the internal gas, thereby facilitating the cracking of the weak portion 2421 to release pressure. In this way, under the same burst pressure, the thickness of the weak portion 2421 can be greater, and when the battery monomer 20 is in normal use, the weak portion 2421 is not easily cracked in advance due to changes in pressure inside the battery monomer 20 or external impact, which is beneficial for reducing the risk of the weak portion 2421 being damaged in advance, and is beneficial for improving the life of the battery monomer 20. Compared with the aluminum material explosion valve in the prior art, the thickness of the weak portion 2421 of the pressure relief mechanism 24 provided in the embodiments of the present application is smaller, and when manufacturing, a slight change in the thickness of the weak portion 2421 will result in a large change in the burst pressure of the battery monomer 20. By extending the first portion 24221 in the direction of approaching or moving away from the electrode assembly 23 relative to the weak portion 2421 at least partially, under the same burst pressure, the thickness of the weak portion 2421 can be increased, and the greater the thickness of the weak portion 2421, the easier it is to manufacture, thereby being beneficial for improving the consistency of the burst pressure of the plurality of battery monomers 20.

[0278] Please refer to 6, 7 and 8, in some embodiments, the first portion 24221 extends in the direction of moving away from the electrode assembly 23 relative to the weak portion 2421 in its entirety.

[0279] Please refer to 6, 7 and 8, in the embodiments shown in the figures, the first portion 24221 extends in the direction of moving away from the electrode assembly 23 relative to the weak portion 2421 in its entirety.

[0280] The existing pressure relief mechanism 24 is gradually arched away from the electrode assembly 23 under the action of the internal pressure of the battery monomer 20 when the pressure relief mechanism 24 is relieved, and then opens the pressure relief under the action of the internal pressure of the battery monomer 20. In the embodiment of the present application, the first part 24221 is extended away from the electrode assembly 23 relative to the weak part 2421, forming a pre-deformation, so as to facilitate the cracking of the weak part 2421 to relieve pressure. In this way, under the same burst pressure, the thickness of the weak part 2421 can be larger, and the weak part 2421 is not easy to crack in advance due to the change of the internal pressure of the battery monomer 20 or external impact when the battery monomer 20 is normally used, which is beneficial to reduce the risk of the weak part 2421 being damaged in advance and improve the service life of the battery monomer 20. By extending the first part 24221 away from the electrode assembly 23 relative to the weak part 2421, the contact area between the body part 2422 and the internal gas is larger when the battery monomer 20 is relieved, the external force applied to the first part 24221 is larger, the first part 24221 can directly pull the weak part 2421, so that the weak part 2421 receives a larger shear force, thereby facilitating the opening of the weak part 2421 to relieve pressure. In the same burst pressure, the thickness of the weak part 2421 can be larger, and the weak part 2421 is not easy to crack in advance due to the change of the internal pressure of the battery monomer 20 or external impact when the battery monomer 20 is normally used, which is beneficial to reduce the risk of the weak part 2421 being damaged in advance and improve the service life of the battery monomer 20. In addition, the larger the thickness of the weak part 2421, the easier it is to manufacture, thereby facilitating the consistency of the burst pressure of the plurality of battery monomers 20.

[0281] Please refer to FIG. 9, in some other embodiments, part of the first part 24221 extends away from the electrode assembly 23 relative to the weak part 2421.

[0282] Please refer to FIG. 9, in the embodiment shown in FIG. 9, the first part 24221 at the left end of the body part 2422 is a straight part, that is, the first part 24221 at the left end of the body part 2422 does not extend relative to the weak part 2421 towards or away from the electrode assembly 23. The first part 24221 at the right end of the body part 2422 extends away from the electrode assembly 23 relative to the weak part 2421. Therefore, in the embodiment shown in FIG. 9, part of the first part 24221 extends away from the electrode assembly 23 relative to the weak part 2421.

[0283] The existing pressure relief mechanism 24 is gradually arched away from the electrode assembly 23 under the action of the internal pressure of the battery monomer 20 when the pressure relief mechanism 24 is relieved, and then opens under the action of the internal pressure of the battery monomer 20. In the embodiment of the present application, a part of the first part 24221 extends away from the electrode assembly 23 relative to the weak part 2421, forming a pre-deformation, so as to facilitate the cracking of the weak part 2421 to relieve pressure. In this way, under the same burst pressure, the thickness of the weak part 2421 can be larger, and the weak part 2421 is not easy to crack in advance due to the change of the internal pressure of the battery monomer 20 or the impact of the external environment during normal use of the battery monomer 20, which is beneficial to reduce the risk of the weak part 2421 being damaged in advance and improve the service life of the battery monomer 20. By extending a part of the first part 24221 away from the electrode assembly 23 relative to the weak part 2421, the contact area between the body part 2422 and the internal gas is larger when the battery monomer 20 is relieved, the external force applied to the first part 24221 is larger, the first part 24221 can directly pull the weak part 2421, so that the weak part 2421 receives a larger shear force, thereby facilitating the opening of the weak part 2421 to relieve pressure. In the same burst pressure, the thickness of the weak part 2421 can be larger, and the weak part 2421 is not easy to crack in advance due to the change of the internal pressure of the battery monomer 20 or the impact of the external environment during normal use of the battery monomer 20, which is beneficial to reduce the risk of the weak part 2421 being damaged in advance and improve the service life of the battery monomer 20. In addition, the larger the thickness of the weak part 2421, the easier it is to manufacture, thereby facilitating the consistency of the burst pressure of the plurality of battery monomers 20. In addition, extending a part of the first part 24221 away from the electrode assembly 23 relative to the weak part 2421 is beneficial to control the extension height of the body part 2422.

[0284] Please refer to FIGS. 3-11, in some embodiments, the electrode assembly 23 includes at least two layers of electrode plates, the at least two layers of electrode plates are stacked, and the stacking direction of the at least two layers of electrode plates is the first direction. Or, the at least two layers of electrode plates are wound, and the at least two layers of electrode plates each include a flat section at the middle of the electrode assembly 23 and a curved section at both ends of the electrode assembly 23, and the stacking direction of the at least two layers of electrode plates at the flat section is the first direction. The body part 2422 is arched in the cross section perpendicular to the at least one plane of the first direction.

[0285] When the electrode assembly 23 is a laminated electrode assembly, the first direction is the stacking direction of the multiple layers of electrode plates. When the electrode assembly 23 is a wound electrode assembly, the first direction is the stacking direction of the multiple layers of electrode plates at the flat section. Please refer to FIG. 4, the first direction is the Z direction shown in the figure. FIGS. 7, 9 and 11 are cross sections of the body part 2422 perpendicular to the plane of the first direction.

[0286] The arch shape can be an arch structure, or a quasi-arch structure, for example, a wave structure.

[0287] By making the cross section of the body portion 2422 in at least one plane perpendicular to the first direction arch-shaped, on the one hand, it is convenient to flow the material when stamping the weak portion 2421, and it is beneficial to improve the stress of the weak portion 2421, so that the formed weak portion 2421 has good structural stability. On the other hand, when the battery cell 20 is depressurized, the contact area of the body portion 2422 with the internal gas is larger, and the external force applied to the body portion 2422 is larger. The body portion 2422 can better transmit the force to the weak portion 2421, thereby pulling the weak portion 2421, so that the weak portion 2421 receives a larger shear force, thereby facilitating the opening of the weak portion 2421 to relieve pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be larger. When the battery cell 20 is normally used, the weak portion 2421 is not easy to break prematurely due to changes in pressure inside the battery cell 20 or external impact, which is beneficial to reduce the risk of the weak portion 2421 being damaged prematurely, and is beneficial to improve the life of the battery cell 20. On the other hand, when the battery cell 20 expands, the arch shape is more easily stretched under external force, thereby reducing the risk of external force being transmitted to the weak portion 2421, which can further reduce the pulling of the weak portion 2421 by external force and reduce the risk of the weak portion 2421 being damaged prematurely, which is beneficial to improve the life of the battery cell 20.

[0288] Please refer to FIGS. 3-11. In some embodiments, the first portion 24221 extends relative to the weak portion 2421 by an extension height H3, which satisfies: 0.5mm≤H3≤5mm.

[0289] H3 represents the extension height of the first portion 24221 relative to the weak portion 2421. In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, and the position corresponding to the pressure relief groove 245 of the pressure relief mechanism 24 forms the weak portion 2421. Please refer to FIGS. 6 and 7. The pressure relief mechanism 24 has a first surface 246 and a second surface arranged opposite in the thickness direction of the wall portion 213. One of the first surface 246 and the second surface faces the electrode assembly 23, and the other of the first surface 246 and the second surface is away from the electrode assembly 23. The pressure relief groove 245 is arranged on the first surface 246. When the first surface 246 is away from the electrode assembly 23, the maximum distance from the second surface to the inner surface of the first portion 24221 can be measured as H3. When the first surface 246 faces the electrode assembly 23, the maximum distance from the second surface to the outer surface of the first portion 24221 can be measured as H3. When the pressure relief mechanism 24 is provided with pressure relief grooves 245 on both sides in the thickness direction of the wall portion 213, the maximum distance from the slot of the pressure relief groove 245 arranged on the side of the pressure relief mechanism 24 away from the electrode assembly 23 to the outer surface of the first portion 24221 can be measured as H3.

[0290] The extension height of the first portion 24221 extending relative to the weakened portion 2421 can be: 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0291] When H3≥0.5 mm, the extension height of the first portion 24221 extending relative to the weakened portion 2421 is higher, so that the deformation of the body portion 2422 is more obvious, and in the case of the same burst pressure, the thickness of the weakened portion 2421 is larger, which is beneficial to reduce the risk of the weakened portion 2421 being damaged in advance, and is beneficial to improve the service life of the battery monomer 20. When H3≤5 mm, the extension height of the first portion 24221 extending relative to the weakened portion 2421 is not too large, on the one hand, it is beneficial to reduce the occupation of the internal space of the battery device 100 or the battery monomer 20, improve the energy density of the battery device 100 or the battery monomer 20, and on the other hand, it is beneficial to reduce the risk of interference between the body portion 2422 and other components. Therefore, when 0.5 mm≤H3≤5 mm, the service life and energy density of the battery monomer 20 can be considered, and the risk of interference between the body portion 2422 and other components is reduced.

[0292] Optionally, 0.8 mm≤H3≤3 mm.

[0293] The extension height of the first portion 24221 extending relative to the weakened portion 2421 can be: 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0294] When H3≥0.8 mm, the extension height of the first portion 24221 extending relative to the weakened portion 2421 is higher, so that the deformation of the body portion 2422 is more obvious, and in the case of the same burst pressure, the thickness of the weakened portion 2421 is larger, which is beneficial to reduce the risk of the weakened portion 2421 being damaged in advance, and is beneficial to improve the service life of the battery monomer 20. When H3≤3 mm, the extension height of the first portion 24221 extending relative to the weakened portion 2421 is not too large, on the one hand, it is beneficial to reduce the occupation of the internal space of the battery device 100 or the battery monomer 20, improve the energy density of the battery device 100 or the battery monomer 20, and on the other hand, it is beneficial to reduce the risk of interference between the body portion 2422 and other components. Therefore, when 0.8 mm≤H3≤3 mm, the service life and energy density of the battery monomer 20 can be considered, and the risk of interference between the body portion 2422 and other components is reduced.

[0295] Please refer to FIG. 12, FIG. 13 and FIG. 14, FIG. 12 is a top view of the pressure relief mechanism 24 according to some embodiments of the present application. FIG. 13 is a sectional view of the position D-D in FIG. 12. FIG. 14 is a sectional view of the pressure relief mechanism 24 according to some embodiments of the present application. In some embodiments, the second portion 2411 extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23.

[0296] The second portion 2411 can extend relative to the weak portion 2421 in a direction close to the electrode assembly 23. The second portion 2411 can also extend relative to the weak portion 2421 in a direction away from the electrode assembly 23.

[0297] Please refer to FIG. 12 and FIG. 13. In the embodiments shown in FIG. 12 and FIG. 13, the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, and the first portion 24221 is a flat portion that does not extend relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23.

[0298] Please refer to FIG. 14. In the embodiments shown in FIG. 14, the second portion 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23, and the first portion 24221 also extends relative to the weak portion 2421 in a direction close to the electrode assembly 23.

[0299] By extending the second portion 2411 relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23, on the one hand, it is convenient to flow the material when stamping the weak portion 2421, which is conducive to improving the stress of the weak portion 2421, so that the structure stability of the formed weak portion 2421 is better. On the other hand, when the battery monomer 20 expands, the second portion 2411 can be stretched under the action of external force, thereby reducing the risk of external force being transmitted to the weak portion 2421, which can further reduce the pulling of the weak portion 2421 by external force, reduce the risk of the weak portion 2421 being damaged in advance, and improve the service life of the battery monomer 20.

[0300] Please refer to FIG. 12, FIG. 13 and FIG. 14. In some embodiments, the connecting portion 241 includes a third portion 2412, the third portion 2412 is used to connect with the wall portion 213, and the second portion 2411 connects the weak portion 2421 and the third portion 2412.

[0301] The third portion 2412 is a portion of the connecting portion 241 used to connect with the wall portion 213, and the third portion 2412 and the weak portion 2421 are respectively connected to two ends of the second portion 2411.

[0302] Optionally, the third portion 2412 is a flat plate structure.

[0303] The third part 2412 is used to connect with the wall part 213. The second wall part 213 connects the weak part 2421 and the third part 2412. In manufacturing, since the third part 2412 is farther away from the weak part 2421 than the second part 2411, the third part 2412 is not easily affected when the weak part 2421 is processed, so that the third part 2412 can keep the original shape, thereby facilitating the connection of the third part 2412 with the wall part 213.

[0304] Please refer to FIG. 12, FIG. 13 and FIG. 14. In some embodiments, the third part 2412 is parallel to the wall part 213.

[0305] The third part 2412 has a third surface facing the wall part 213, and the wall part 213 has a fourth surface facing the third part 2412, and the third surface and the fourth surface are parallel. It should be noted that the "third surface and fourth surface are parallel" herein means that the third surface and the fourth surface are substantially parallel, and the angle between the third surface and the fourth surface is less than 5°.

[0306] By making the third part 2412 parallel to the wall part 213, the connection of the third part 2412 with the wall part 213 is more convenient, which is conducive to increasing the stability of the connection of the third part 2412 with the wall part 213.

[0307] Please refer to FIG. 12, FIG. 13 and FIG. 14. In some embodiments, the second part 2411 is arranged to be inclined relative to the third part 2412, and the inclination angle of the second part 2411 relative to the third part 2412 is a, which satisfies: 40°≤a≤75°.

[0308] a represents the inclination angle of the second part 2411 relative to the third part 2412. In this embodiment, the third part 2412 is horizontal, so the inclination angle of the second part 2411 relative to the third part 2412 is the angle between the second part 2411 and the horizontal direction. When measuring, the angle between one surface of the second part 2411 and the horizontal plane can be measured.

[0309] The inclination angle of the second part 2411 relative to the third part 2412 can be: a=40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, etc.

[0310] When a≥40°, the inclination degree of the connecting part 241 is large, and the constraint effect on the weak part 2421 is good, which is conducive to reducing the risk of creep failure of the weak part 2421. When a≤75°, the inclination degree of the connecting part 241 is not too large, which is conducive to reducing stress concentration and reducing the risk of brittle fracture.

[0311] Please refer to FIG. 6, FIG. 7 and FIG. 14, in some embodiments, the first portion 24221 and the second portion 2411 both extend relative to the weak portion 2421, and the first portion 24221 extends relative to the weak portion 2421 in the same direction as the second portion 2411 extends relative to the weak portion 2421.

[0312] The first portion 24221 and the second portion 2411 can both extend relative to the weak portion 2421 in a direction away from the electrode assembly 23, or the first portion 24221 and the second portion 2411 can both extend relative to the weak portion 2421 in a direction close to the electrode assembly 23.

[0313] When the first portion 24221 extends relative to the weak portion 2421 in the same direction as the second portion 2411 extends relative to the weak portion 2421, the first portion 24221 can extend with the extension height of the second portion 2411, thereby facilitating to reduce the height of the body portion 2422 beyond the surface of the connection portion 241 farthest away from the electrode assembly 23 or to reduce the height of the body portion 2422 beyond the surface of the connection portion 241 closest to the electrode assembly 23, reduce the occupation of the internal space of the battery device 100 or the battery cell 20, and facilitate to improve the energy density of the battery device 100 or the battery cell 20. In addition, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 respectively apply action forces in opposite directions to the weak portion 2421, so that the weak portion 2421 is subjected to a shearing force, facilitating the weak portion 2421 to open and depressurize. Under the same burst pressure, the thickness of the weak portion 2421 can be greater, and the weak portion 2421 is less likely to be prematurely cracked due to the pressure change inside the battery cell 20 or external impact during normal use of the battery cell 20, thereby facilitating to reduce the risk of the weak portion 2421 being prematurely damaged and improving the service life of the battery cell 20. Moreover, when the battery cell 20 swells, the first portion 24221 and the second portion 2411 are more easily stretched under external force, thereby reducing the risk of the external force being transmitted to the weak portion 2421, further reducing the risk of the external force pulling the weak portion 2421, reducing the risk of the weak portion 2421 being prematurely damaged, and improving the service life of the battery cell 20.

[0314] Please refer to FIG. 14, in some embodiments, the first portion 24221 and the second portion 2411 both extend relative to the weak portion 2421 in a direction close to the electrode assembly 23.

[0315] When the first portion 24221 and the second portion 2411 are both extended relative to the weak portion 2421 in a direction close to the electrode assembly 23, the first portion 24221 is allowed to extend by the extension height of the second portion 2411, thereby facilitating reduction of the height of the body portion 2422 beyond the surface of the connecting portion 241 closest to the electrode assembly 23, reduction of the occupation of the internal space of the battery cell 20, and improvement of the energy density of the battery cell 20. In addition, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 respectively apply forces in opposite directions to the weak portion 2421, so that the weak portion 2421 is subjected to a shearing force, facilitating the opening of the weak portion 2421 for depressurization. In the case of the same burst pressure, the thickness of the weak portion 2421 can be greater, and the weak portion 2421 is less likely to be prematurely cracked due to changes in the pressure inside the battery cell 20 or external impacts during normal use of the battery cell 20, thereby reducing the risk of premature destruction of the weak portion 2421 and improving the service life of the battery cell 20.

[0316] Please refer to FIGS. 6 and 7. In some other embodiments, the first portion 24221 and the second portion 2411 are both extended relative to the weak portion 2421 in a direction away from the electrode assembly 23.

[0317] When the first portion 24221 and the second portion 2411 are both extended relative to the weak portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 is allowed to extend by the extension height of the second portion 2411, thereby facilitating reduction of the height of the body portion 2422 beyond the surface of the connecting portion 241 farthest from the electrode assembly 23, reduction of the occupation of the internal space of the battery device 100, and improvement of the energy density of the battery device 100. In addition, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 respectively apply forces in opposite directions to the weak portion 2421, so that the weak portion 2421 is subjected to a shearing force, facilitating the opening of the weak portion 2421 for depressurization. In the case of the same burst pressure, the thickness of the weak portion 2421 can be greater, and the weak portion 2421 is less likely to be prematurely cracked due to changes in the pressure inside the battery cell 20 or external impacts during normal use of the battery cell 20, thereby reducing the risk of premature destruction of the weak portion 2421 and improving the service life of the battery cell 20.

[0318] Please refer to FIGS. 15 and 16. FIG. 15 is a cross-sectional view of a pressure relief mechanism 24 according to some other embodiments of the present application. FIG. 16 is a cross-sectional view of a pressure relief mechanism 24 according to some other embodiments of the present application. In some embodiments, the first portion 24221 and the second portion 2411 are both extended relative to the weak portion 2421, and the direction in which the first portion 24221 is extended relative to the weak portion 2421 is opposite to the direction in which the second portion 2411 is extended relative to the weak portion 2421.

[0319] The opposite directions of the first portion 2422 1 extending relative to the weakened portion 2421 and the second portion 241 1 extending relative to the weakened portion 2421 can be that the first portion 2422 1 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23 and the second portion 241 1 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23, or that the first portion 2422 1 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 and the second portion 241 1 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23.

[0320] By making the opposite directions of the first portion 2422 1 extending relative to the weakened portion 2421 and the second portion 241 1 extending relative to the weakened portion 2421, when connecting the connecting portion 241 to the wall portion 213, the weakened portion 2421 is less likely to be affected, which is conducive to maintaining the performance of the weakened portion 2421 and improving the service life of the battery cell 20.

[0321] Please refer to FIG. 15, in some embodiments, the first portion 2422 1 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23, and the second portion 241 1 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23.

[0322] By making the first portion 2422 1 extend relative to the weakened portion 2421 in a direction close to the electrode assembly 23 and the second portion 241 1 extend relative to the weakened portion 2421 in a direction away from the electrode assembly 23, it is conducive to reducing the occupation of the internal space of the battery device 100, improving the energy density of the battery device 100, and reducing the risk of interference between the body portion 2422 and other components in the battery device 100.

[0323] Please refer to FIG. 16, in some other embodiments, the first portion 2422 1 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23, and the second portion 241 1 extends relative to the weakened portion 2421 in a direction close to the electrode assembly 23.

[0324] By making the first portion 2422 1 extend relative to the weakened portion 2421 in a direction away from the electrode assembly 23 and the second portion 241 1 extend relative to the weakened portion 2421 in a direction close to the electrode assembly 23, it is conducive to reducing the occupation of the internal space of the battery cell 20, improving the energy density of the battery cell 20, and reducing the risk of interference between the body portion 2422 and other components in the battery cell 20.

[0325] Please refer to FIG. 6, FIG. 7 and FIG. 8 again, in some embodiments, the minimum thickness of the weakened portion 2421 is H4, which satisfies 0.01mm≤H4≤0.2mm.

[0326] H4 represents the minimum thickness of the weak portion 2421 in the thickness direction of the wall portion 213. When measuring, the thickness of different positions of the weak portion 2421 can be measured multiple times and the average value is taken as H4.

[0327] The minimum thickness of the weak portion 2421 in the thickness direction of the wall portion 213 can be: H4 = 0.01 mm, 0.02 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, etc.

[0328] When H4≥0.01 mm, the thickness of the weak portion 2421 is large, and the weak portion 2421 is not easy to crack prematurely due to changes in pressure inside the battery monomer 20 or external impact, which is beneficial to reduce the risk of the weak portion 2421 being damaged prematurely, and is beneficial to improve the service life of the battery monomer 20. When H4≤0.2 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief in time when the battery monomer 20 is out of control, which is beneficial to improve the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 0.01 mm≤H4≤0.2 mm, the service life and pressure relief timeliness of the battery monomer 20 can be considered.

[0329] In some embodiments, in the thickness direction of the wall portion 213, the projection area of the body portion 2422 is S; wherein, 100 mm 2 ≤450 mm 2 , and 0.010 mm≤H4≤0.160 mm; or, 350 mm 2 ≤S≤850 mm 2 , and 0.015 mm≤H4≤0.170 mm; or, 750 mm 2 ≤S≤1250 mm 2 , and 0.020 mm≤H4≤0.180 mm; or, 1150 mm 2 ≤S≤1650 mm 2 , and 0.025 mm≤H4≤0.190 mm; or, 1550 mm 2 ≤S≤2100 mm 2 , and 0.030 mm≤H4≤0.200 mm.

[0330] S represents the projection area of the body portion 2422 in the thickness direction of the wall portion 213. Please refer to FIG. 6, in which S is indicated by the mesh line. It should be noted that the mesh line here is only to facilitate the display of S, and does not represent any entity meaning.

[0331] The projection area of the body portion 2422 in the thickness direction of the wall portion 213 can be: S = 100 mm 2 , 150 mm 2200mm 2 250mm 2 300mm 2 350mm 2 400mm 2 450mm 2 500mm 2 550mm 2 600mm 2 650mm 2 700mm 2 750mm 2 800mm 2 850mm 2 900mm 2 950mm 2 1000mm 2 1050mm 2 1100mm 2 1150mm 2 1200mm 2 1250mm 2 1300mm 2 1350mm 2 1400mm 2 1450mm 2 1500mm 2 1550mm 2 1600mm 2 1650mm 2 1700mm 2 1750mm 2 1800mm 2 1850mm 2 1900mm 2 1950mm 2 2000mm 2 2050mm 2 2100mm 2 wait.

[0332] When 100mm 2 ≤S≤450mm 2 When 0.010mm ≤ H4 ≤ 0.160mm. When 100mm 2 ≤S≤450mm 2When the minimum thickness of the weak portion 2421 in the thickness direction of the wall portion 213 is 0.010 mm, 0.020 mm, 0.030 mm, 0.040 mm, 0.050 mm, 0.060 mm, 0.070 mm, 0.080 mm, 0.090 mm, 0.100 mm, 0.110 mm, 0.120 mm, 0.130 mm, 0.140 mm, 0.150 mm, 0.160 mm, or the like, the weak portion 2421 is less likely to be broken due to the internal pressure of the battery cell 20 or external impact, and the risk of the weak portion 2421 being broken prematurely is reduced, which is advantageous in improving the service life of the battery cell 20.

[0333] When the projected area of the body portion 2422 is large, the body portion 2422 is more likely to be broken due to the internal pressure, and thus, when the projected area of the body portion 2422 is large, the thickness of the weak portion 2421 can be increased to ensure the same burst pressure. When 100 mm 2 ≤ S ≤ 450 mm 2 When H4≥ 0.010 mm, the thickness of the weak portion 2421 is large, and the weak portion 2421 is less likely to be broken prematurely due to the internal pressure of the battery cell 20 or external impact, which is advantageous in reducing the risk of the weak portion 2421 being broken prematurely and improving the service life of the battery cell 20. When 100 mm 2 ≤ S ≤ 450 mm 2 When H4≤ 0.160 mm, the thickness of the weak portion 2421 is not too large, and thus, when the battery cell 20 is in thermal runaway, the pressure relief mechanism 24 can be opened in time, which is advantageous in improving the timeliness of the pressure relief of the pressure relief mechanism 24. Thus, when 100 mm 2 ≤ S ≤ 450 mm 2 When 0.010 mm ≤ H4≤ 0.160 mm, the service life of the battery cell 20 and the timeliness of the pressure relief can be considered.

[0334] When 350 mm 2 ≤ S ≤ 850 mm 2 0.015 mm ≤ H4≤ 0.170 mm. When 350 mm 2 ≤ S ≤ 850 mm 2 When the minimum thickness of the weak portion 2421 in the thickness direction of the wall portion 213 is 0.015 mm, 0.020 mm, 0.030 mm, 0.040 mm, 0.050 mm, 0.060 mm, 0.070 mm, 0.080 mm, 0.090 mm, 0.100 mm, 0.110 mm, 0.120 mm, 0.130 mm, 0.140 mm, 0.150 mm, 0.160 mm, 0.170 mm, or the like, the weak portion 2421 is less likely to be broken due to the internal pressure of the battery cell 20 or external impact, and the risk of the weak portion 2421 being broken prematurely is reduced, which is advantageous in improving the service life of the battery cell 20.

[0335] When 350 mm 2 ≤ S ≤ 850 mm 2, and H4≥0.015mm, the thickness of the weak portion 2421 is large, the weak portion 2421 is not easy to crack in advance due to the pressure change inside the battery monomer 20 or external impact, which is conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is conducive to improving the service life of the battery monomer 20. When 350mm 2 ≤S≤850mm 2 , and H4≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can be opened in time when the battery monomer 20 is out of control, which is conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered.

[0336] When 750mm 2 ≤S≤1250mm 2 , 0.020mm≤H4≤0.180mm. When 750mm 2 ≤S≤1250mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4=0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, etc.

[0337] When 750mm 2 ≤S≤1250mm 2 , and H4≥0.020mm, the thickness of the weak portion 2421 is large, the weak portion 2421 is not easy to crack in advance due to the pressure change inside the battery monomer 20 or external impact, which is conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is conducive to improving the service life of the battery monomer 20. When 750mm 2 ≤S≤1250mm 2 , and H4≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can be opened in time when the battery monomer 20 is out of control, which is conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered.

[0338] When 1150mm2 ≤S≤1650mm 2 When 1150mm 2 ≤S≤1650mm 2 mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, 0.190mm, etc.

[0339] When 1150mm 2 ≤S≤1650mm 2 mm, the thickness of the weakened portion 2421 is large, the weakened portion 2421 is not easy to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is conducive to reducing the risk of the weakened portion 2421 being damaged in advance, and is conducive to improving the service life of the battery monomer 20. When 1150mm 2 ≤S≤1650mm 2 mm, the thickness of the weakened portion 2421 is not too large, so that the pressure relief mechanism 24 can be opened in time when the battery monomer 20 is out of control, which is conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550mm 2 ≤S≤2100mm 2 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered.

[0340] When 1550mm 2 ≤S≤2100mm 2 mm. When 1550mm 2 ≤S≤2100mm 2 mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, 0.190mm, 0.200mm, etc.

[0341] When 1550mm 2≤ S ≤ 2100 mm 2 When H4≥0.030 mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not prone to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is conducive to reducing the risk of the weak portion 2421 being damaged in advance and improving the service life of the battery monomer 20. When 1550 mm 2 ≤ S ≤ 2100 mm 2 When H4≤0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can be opened in time when the battery monomer 20 is out of control, which is conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm 2 ≤ S ≤ 2100 mm 2 When 0.030 mm≤H4≤0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered.

[0342] In some embodiments, 100 mm 2 ≤ S ≤ 450 mm 2 , and 0.020 mm≤H4≤0.160 mm; or, 350 mm 2 ≤ S ≤ 850 mm 2 , and 0.025 mm≤H4≤0.170 mm; or, 750 mm 2 ≤ S ≤ 1250 mm 2 , and 0.030 mm≤H4≤0.180 mm; or, 1150 mm 2 ≤ S ≤ 1650 mm 2 , and 0.035 mm≤H4≤0.190 mm; or, 1550 mm 2 ≤ S ≤ 2100 mm 2 , and 0.040 mm≤H4≤0.200 mm.

[0343] When 100 mm 2 ≤ S ≤ 450 mm 2 , 0.020 mm≤H4≤0.160 mm. When 100 mm 2 ≤ S ≤ 450 mm 2When the weak part 2421 has a minimum thickness along the thickness direction of the wall part 213, it can be: H4 = 0.020mm, 0.025mm, 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, etc.

[0344] When 100mm 2 <S≤450mm 2 Furthermore, when H4 ≥ 0.020 mm, the thickness of the weak portion 2421 is greater, making it less prone to premature cracking due to internal pressure changes or external impacts within the battery cell 20. This reduces the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When 100 mm... 2 <S≤450mm 2 When H4 ≤ 0.160 mm, the thickness of the weak part 2421 will not be too large, allowing the pressure relief mechanism 24 to open more promptly in the event of thermal runaway of the battery cell 20, thus improving the timeliness of pressure relief. Therefore, when 100 mm 2 <S≤450mm 2 Furthermore, when H4 is 0.020mm≤H4≤0.160mm, it is better able to balance the service life of the battery cell 20 and the timeliness of pressure relief.

[0345] When 350mm 2 ≤S≤850mm 2 When 0.025mm ≤ H4 ≤ 0.170mm. When 350mm 2 ≤S≤850mm 2When the weak part 2421 has a minimum thickness along the thickness direction of the wall part 213, it can be: H4 = 0.025mm, 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm. 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, etc.

[0346] When 350mm 2 ≤S≤850mm 2 Furthermore, when H4 ≥ 0.025 mm, the thickness of the weak portion 2421 is greater, making it less prone to premature cracking due to internal pressure changes or external impacts within the battery cell 20. This reduces the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When 350 mm... 2 ≤S≤850mm 2 When H4 ≤ 0.170 mm, the thickness of the weak part 2421 will not be too large, allowing the pressure relief mechanism 24 to open more promptly in the event of thermal runaway of the battery cell 20, thus improving the timeliness of pressure relief. Therefore, when 350 mm 2 ≤S≤850mm 2 Furthermore, when H4 is 0.025mm≤H4≤0.170mm, it is better able to balance the service life of the battery cell 20 and the timeliness of pressure relief.

[0347] When 750mm 2 ≤S≤1250mm 2 When 0.030mm ≤ H4 ≤ 0.180mm. When 750mm 2 ≤S≤1250mm 2When the weak part 2421 has a minimum thickness along the thickness direction of the wall part 213, it can be: H4 = 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, etc.

[0348] When 750mm 2 ≤S≤1250mm 2 Furthermore, when H4 ≥ 0.030 mm, the thickness of the weak portion 2421 is greater, making it less prone to premature cracking due to internal pressure changes or external impacts within the battery cell 20. This reduces the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When 750 mm... 2 ≤S≤1250mm 2 When H4 ≤ 0.180 mm, the thickness of the weak part 2421 will not be too large, allowing the pressure relief mechanism 24 to open more promptly in the event of thermal runaway of the battery cell 20, thus improving the timeliness of pressure relief. Therefore, when 750 mm 2 ≤S≤1250mm 2 Furthermore, when H4 is 0.030mm≤H4≤0.180mm, it is better able to balance the service life of the battery cell 20 and the timeliness of pressure relief.

[0349] When 1150mm 2 ≤S≤1650mm 2 When 0.035mm ≤ H4 ≤ 0.190mm. When 1150mm 2 ≤S≤1650mm 2When the weak part 2421 has a minimum thickness along the thickness direction of the wall part 213, it can be: H4 = 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm. 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, 0.185mm, 0.190mm, etc.

[0350] When 1150mm 2 ≤S≤1650mm 2 Furthermore, when H4 ≥ 0.035 mm, the thickness of the weak portion 2421 is greater, making it less prone to premature cracking due to internal pressure changes or external impacts within the battery cell 20. This reduces the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When 1150 mm... 2 ≤S≤1650mm 2 When H4 ≤ 0.190 mm, the thickness of the weak part 2421 will not be too large, allowing the pressure relief mechanism 24 to open more promptly in the event of thermal runaway of the battery cell 20, thus improving the timeliness of pressure relief. Therefore, when 1550 mm 2 ≤S≤2100mm 2 Furthermore, when H4 is 0.035mm≤H4≤0.190mm, it is better able to balance the service life of the battery cell 20 and the timeliness of pressure relief.

[0351] When 1550mm 2 ≤S≤2100mm 2 When 0.040mm ≤ H4 ≤ 0.200mm. When 1550mm 2 ≤S≤2100mm 2When 1550 mm < S < 2100 mm, and H4 ≥ 0.040 mm, the thickness of the weak portion 2421 is larger, the weak portion 2421 is less likely to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is more conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is more conducive to improving the service life of the battery monomer 20. When 1550 mm < S < 2100 mm, and H4 ≤ 0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief more timely when the battery monomer 20 is out of control, which is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm < S < 2100 mm, and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered at the same time.

[0352] When 1550 mm < S < 2100 mm, and H4 ≥ 0.040 mm, the thickness of the weak portion 2421 is larger, the weak portion 2421 is less likely to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is more conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is more conducive to improving the service life of the battery monomer 20. When 1550 mm < S < 2100 mm, and H4 ≤ 0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief more timely when the battery monomer 20 is out of control, which is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm < S < 2100 mm, and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered at the same time. 2 ≤ S < 2100 mm 2 When 1550 mm < S < 2100 mm, and H4 ≥ 0.040 mm, the thickness of the weak portion 2421 is larger, the weak portion 2421 is less likely to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is more conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is more conducive to improving the service life of the battery monomer 20. When 1550 mm < S < 2100 mm, and H4 ≤ 0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief more timely when the battery monomer 20 is out of control, which is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm < S < 2100 mm, and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered at the same time. 2 ≤ S < 2100 mm 2 When 1550 mm < S < 2100 mm, and H4 ≥ 0.040 mm, the thickness of the weak portion 2421 is larger, the weak portion 2421 is less likely to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is more conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is more conducive to improving the service life of the battery monomer 20. When 1550 mm < S < 2100 mm, and H4 ≤ 0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief more timely when the battery monomer 20 is out of control, which is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm < S < 2100 mm, and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered at the same time. 2 ≤ S < 2100 mm 2 When 1550 mm < S < 2100 mm, and H4 ≥ 0.040 mm, the thickness of the weak portion 2421 is larger, the weak portion 2421 is less likely to be cracked in advance due to the pressure change inside the battery monomer 20 or external impact, which is more conducive to reducing the risk of the weak portion 2421 being damaged in advance, and is more conducive to improving the service life of the battery monomer 20. When 1550 mm < S < 2100 mm, and H4 ≤ 0.200 mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open the pressure relief more timely when the battery monomer 20 is out of control, which is more conducive to improving the timeliness of the pressure relief of the pressure relief mechanism 24. Therefore, when 1550 mm < S < 2100 mm, and 0.040 mm ≤ H4 ≤ 0.200 mm, the service life and the timeliness of the pressure relief of the battery monomer 20 can be considered at the same time.

[0353] Please refer to FIG. 17, which is a schematic diagram of the connection between the pressure relief mechanism 24, the wall portion 213 and the support structure 28 provided by some embodiments of the present application. In some embodiments, the connecting portion 241 is welded to the wall portion 213.

[0354] The connecting portion 241 can be butt welded with the wall portion 213, or the connecting portion 241 can be penetration welded with the wall portion 213.

[0355] The base material of the pressure relief mechanism 24 and the wall portion 213 is iron, and the connecting portion 241 and the wall portion 213 are easy to weld, which is beneficial to reduce the phenomenon of welding cracks between the pressure relief mechanism 24 and the wall portion 213, thereby reducing the risk of liquid leakage of the battery monomer 20 and improving the reliability of the battery monomer 20.

[0356] Please refer to FIG. 17. In some embodiments, the battery monomer 20 further comprises a support structure 28 fixed to the side of the wall portion 213 facing the electrode assembly 23, and the pressure relief mechanism 24 is located on the side of the support structure 28 away from the electrode assembly 23. The connecting portion 241 is welded to the support structure 28, and the base material of the support structure 28 is iron.

[0357] The support structure 28 is located on the side of the wall portion 213 facing the electrode assembly 23 and on the side of the pressure relief mechanism 24 facing the electrode assembly 23. Along the thickness direction of the wall portion 213, a part of the support structure 28 is arranged in a stack with the wall portion 213, and another part of the support structure 28 is arranged in a stack with the pressure relief mechanism 24. In this way, the external space of the battery monomer 20 occupied by the support structure 28 can be saved, and the fixed connection between the pressure relief mechanism 24 and the wall portion 213 can be easily achieved.

[0358] Optionally, the support structure is annular.

[0359] The "base material of the support structure 28 is iron" means that the material with the largest mass percentage in the material of the support structure 28 is iron. For example, the material of the support structure 28 can be carbon steel or stainless steel.

[0360] The connecting portion 241 is welded to the wall portion 213 and the support structure 28 to have higher connection strength.

[0361] By arranging the support structure 28, when welding the connecting portion 241 and the wall portion 213, the support structure 28 can reduce the risk of laser passing through the gap between the connecting portion 241 and the wall portion 213 and acting on the electrode assembly 23, which is beneficial to improve the reliability of the battery monomer 20. In addition, the support structure 28 can play a positioning role in the fixed connection process of the pressure relief mechanism 24 and the wall portion 213, and the support structure 28 can also be used to achieve the connection and fixation between the pressure relief mechanism 24 and the wall portion 213, which can effectively improve the processing efficiency of the battery monomer 20. The support structure 28 can also be used to support the pressure relief mechanism 24 and the wall portion 213, increase the structural strength and stability between the wall portion 213 and the pressure relief mechanism 24, and especially during the use of the battery monomer 20, the battery monomer 20 will swell, the support structure 28 can also be used to resist deformation, reduce the cracking between the pressure relief mechanism 24 and the wall portion 213 caused by the swelling of the battery monomer 20, and improve the stability of the battery monomer 20.

[0362] In some embodiments, the support structure 28 is fixed to the wall portion 213 by welding or by adhesion.

[0363] When the support structure 28 is fixed to the wall portion 213 by welding, the support structure 28 and the wall portion 213 have high connection strength. When the support structure 28 is fixed to the wall portion 213 by adhesion, the support structure 28 and the wall portion 213 are connected conveniently, which is conducive to reducing production cost.

[0364] Please refer to FIG. 17. In some embodiments, in the direction close to the electrode assembly 23, the pressure relief mechanism 24 does not exceed the surface of the support structure 28 facing the electrode assembly 23.

[0365] No matter whether at least one of the first portion 24221 and the second portion 2411 of the pressure relief mechanism 24 extends relative to the weak portion 2421 in the direction close to the electrode assembly 23 or in the direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 facing the electrode assembly 23 does not exceed the surface of the support structure 28 facing the electrode assembly 23, so as to protect the pressure relief mechanism 24.

[0366] By making the pressure relief mechanism 24 not exceed the surface of the support structure 28 facing the electrode assembly 23 in the direction close to the electrode assembly 23, on the one hand, it is conducive to reducing the risk of interference between the pressure relief mechanism 24 and other components in the battery monomer 20, and on the other hand, it is also conducive to reducing the risk of the pressure relief mechanism 24 being subjected to external force applied by other components of the battery monomer 20, so that the weak portion 2421 is not easy to be broken in advance, which is conducive to reducing the risk of the weak portion 2421 being damaged in advance and is conducive to improving the service life of the battery monomer 20.

[0367] Please refer to FIG. 17. In some embodiments, the thickness of the support structure 28 is H5, which satisfies: 0.4mm≤H5≤1.5mm.

[0368] H5 represents the thickness of the support structure 28. When measuring, the thickness can be measured multiple times and the average value is taken as H5.

[0369] The thickness of the support structure 28 can be: H5=0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.5mm, etc.

[0370] When H5 is greater than or equal to 0.4 mm, the thickness of the support structure 28 is relatively large, and the laser during welding is not easy to penetrate the support structure 28, which can effectively reduce the risk of the laser passing through the gap between the connecting portion 241 and the wall portion 213 and acting on the electrode assembly 23, and is conducive to improving the reliability of the battery monomer 20. When H5 is less than or equal to 1.5 mm, the thickness of the support structure 28 is not too large, on the one hand, the support structure 28 can reduce the occupation of the internal space of the battery monomer 20, and improve the energy density of the battery monomer 20. On the other hand, the material consumption of the support structure 28 can be reduced, and the manufacturing cost of the battery monomer 20 can be reduced. Therefore, when 0.4 mm≤H5≤1.5 mm, the reliability, energy density and manufacturing cost of the battery monomer 20 can be considered.

[0371] Optionally, 0.4 mm≤H5≤0.8 mm.

[0372] The thickness of the support structure 28 can be: H5=0.4 mm, 0.42 mm, 0.45 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.55 mm, 0.58 mm, 0.6 mm, 0.62 mm, 0.65 mm, 0.68 mm, 0.7 mm, 0.72 mm, 0.75 mm, 0.78 mm, 0.8 mm, etc.

[0373] When H5 is greater than or equal to 0.4 mm, the thickness of the support structure 28 is relatively large, and the laser during welding is not easy to penetrate the support structure 28, which can effectively reduce the risk of the laser passing through the gap between the connecting portion 241 and the wall portion 213 and acting on the electrode assembly 23, and is conducive to improving the reliability of the battery monomer 20. When H5 is less than or equal to 0.8 mm, the thickness of the support structure 28 is not too large, on the one hand, the support structure 28 can reduce the occupation of the internal space of the battery monomer 20, and improve the energy density of the battery monomer 20. On the other hand, the material consumption of the support structure 28 can be reduced, and the manufacturing cost of the battery monomer 20 can be reduced. Therefore, when 0.4 mm≤H5≤0.8 mm, the reliability, energy density and manufacturing cost of the battery monomer 20 can be considered.

[0374] Please refer to FIG. 17, in some embodiments, the pressure relief mechanism 24, the wall portion 213 and the support structure 28 are connected by the same welding seam 281.

[0375] The wall portion 213 is provided with a pressure relief hole 2131, and the pressure relief mechanism 24 is accommodated in the pressure relief hole 2131. The outer circumferential surface of the pressure relief mechanism 24, the hole wall surface of the pressure relief hole 2131 and the support structure 28 are connected by the same welding seam 281. Please refer to FIG. 17, the connecting portion 241 and the hole wall of the pressure relief hole 2131 can be fixed by means of seam welding, and the welding seam 281 is formed, at the same time, the support structure 28 is also welded and fixed to the side of the welding seam 281 facing the inside of the battery monomer 20.

[0376] In the welding, the pressure relief mechanism 24, the wall portion 213 and the support structure 28 can be welded at one time, which is simple and convenient.

[0377] Please refer to FIG. 18, which is a schematic diagram of the connection of the pressure relief mechanism 24, the wall portion 213, the support structure 28 and the partition 29 provided by some embodiments of the present application. In some embodiments, the battery cell 20 further comprises the partition 29, which is arranged on the side of the wall portion 213 facing the electrode assembly 23. In the direction close to the electrode assembly 23, the pressure relief mechanism 24 at least partially protrudes from the surface of the wall portion 213 facing the electrode assembly 23, and the partition 29 protrudes from the surface of the pressure relief mechanism 24 facing the electrode assembly 23.

[0378] The partition 29 is arranged on the side of the wall portion 213 facing the electrode assembly 23, and the partition 29 protrudes from the surface of the pressure relief mechanism 24 facing the electrode assembly 23, so as to protect the pressure relief mechanism 24.

[0379] In some embodiments, the partition 29 protrudes from the surface of the support structure 28 facing the electrode assembly 23. In other embodiments, the surface of the partition 29 facing the electrode assembly 23 is flush with the surface of the support structure 28 facing the electrode assembly 23.

[0380] When the wall portion 213 is the end cover 212, the partition 29 can be a lower plastic. When the wall portion 213 is the side wall of the shell 211, the partition 29 can be a side support plate. When the wall portion 213 is the bottom wall of the shell 211, the partition 29 can be a bottom support plate. Of course, the partition 29 can also be an additional pad plate.

[0381] The pressure relief mechanism 24 at least partially protrudes from the surface of the wall portion 213 facing the electrode assembly 23 in the direction close to the electrode assembly 23. By making the partition 29 protrude from the surface of the pressure relief mechanism 24 facing the electrode assembly 23 in the direction close to the electrode assembly 23, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism 24 and other components in the battery cell 20, and on the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism 24 being subjected to external force from other components in the battery cell 20, so that the weak portion 2421 is not easy to break in advance, which is beneficial to reduce the risk of the weak portion 2421 being damaged in advance and improve the service life of the battery cell 20.

[0382] Please refer to FIG. 18 and FIG. 19, which is a schematic diagram of the structure of the partition 29 provided by some embodiments of the present application. In some embodiments, the partition 29 comprises a fourth portion 291 and a fifth portion 292 arranged at intervals, and the pressure relief mechanism 24 is located between the fourth portion 291 and the fifth portion 292.

[0383] The fourth part 291 and the fifth part 292 are independent of each other and are not connected to each other. In manufacturing, the fourth part 291 and the fifth part 292 can be manufactured separately and then assembled at two ends of the pressure relief mechanism 24.

[0384] The partition 29 includes the fourth part 291 and the fifth part 292 which are spaced apart. By locating the pressure relief mechanism 24 between the fourth part 291 and the fifth part 292, on the one hand, the fourth part 291 and the fifth part 292 do not easily affect the opening of the pressure relief mechanism 24, so that the battery monomer 20 can be timely relieved. On the other hand, in manufacturing, the fourth part 291 and the fifth part 292 can be manufactured separately and then arranged at two sides of the pressure relief mechanism 24, which is beneficial to simplify the manufacturing and reduce the assembly difficulty.

[0385] Optionally, the partition 29 can also include more than two split structures which are spaced apart around the pressure relief mechanism 24 to protect the pressure relief mechanism 24. In this way, the partition 29 is arranged more flexibly.

[0386] Please refer to FIG. 20, which is a structural schematic diagram of the partition 29 provided by some other embodiments of the present application. In some other embodiments, the partition 29 is provided with a relief opening 293 which is used to avoid the pressure relief mechanism 24.

[0387] The relief opening 293 is a through hole arranged in the partition 29. Optionally, the shape of the relief opening 293 matches the outer contour of the pressure relief mechanism 24. For example, when the outer contour of the pressure relief mechanism 24 is in the shape of a racetrack, the relief opening 293 can also be in the shape of a racetrack.

[0388] By arranging the relief opening 293 to avoid the pressure relief mechanism 24, it is beneficial to allow the pressure relief mechanism 24 to open when the pressure inside the shell 21 reaches the threshold value.

[0389] Please refer to FIG. 21 and FIG. 22, FIG. 21 is a sectional view of the partition 29 provided by some other embodiments of the present application. FIG. 22 is a sectional view of the partition 29 provided by some other embodiments of the present application. In some other embodiments, the partition 29 is provided with a containing groove 294 which is arranged with an opening facing the pressure relief mechanism 24 and is used to contain the pressure relief mechanism 24. The bottom of the containing groove 294 is provided with a thinned area 2941 which corresponds to the pressure relief mechanism 24 and has a thickness smaller than that of other areas of the bottom of the containing groove 294.

[0390] In one aspect, the inner space of the accommodating groove 294 can be used to avoid the pressure relief mechanism 24 and the support structure 28, and the thinned area 2941 provided on the bottom wall of the accommodating groove 294 can be used to be timely broken when the battery monomer 20 is in thermal runaway, so as to reduce the influence of the bottom wall of the accommodating groove 294 on the pressure relief mechanism 24, so that the pressure relief mechanism 24 can be timely broken and the pressure inside the battery monomer 20 can be timely released.

[0391] Please refer to FIG. 21. In the embodiment shown in FIG. 21, the thinned area 2941 of the bottom wall of the accommodating groove 294 can be a groove structure, and the area of the thinned area 2941 covers at least the weak part 2421 of the pressure relief mechanism 24, so as to reduce the influence on the actuation of the pressure relief mechanism 24.

[0392] Please refer to FIG. 22. In the embodiment shown in FIG. 22, the thinned area 2941 of the bottom wall of the accommodating groove 294 can also be an annular structure, so that the thinned area 2941 corresponds to the annular weak part 2421 of the pressure relief mechanism 24, so as to reduce the influence on the actuation of the pressure relief mechanism 24.

[0393] By arranging the accommodating groove 294 to accommodate the pressure relief mechanism 24, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism 24 and other components in the battery monomer 20, and on the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism 24 being subjected to external force from other components of the battery monomer 20, so that the weak part 2421 is not easy to break in advance, which is beneficial to reduce the risk of the weak part 2421 being broken in advance, and is beneficial to improve the service life of the battery monomer 20. By forming the thinned area 2941 at the bottom of the accommodating groove 294, when the pressure inside the shell 21 reaches a threshold value, the thinned area 2941 can be opened, so as to provide a path for the gas in the shell 21 to flow to the pressure relief mechanism 24, thereby facilitating the opening of the pressure relief mechanism 24.

[0394] It should be understood that the size of the partition 29 of the embodiment of the present application can be set according to actual application. For example, in the case that the partition 29 is provided with the avoiding opening 293 or the accommodating groove 294, the size of each direction of the avoiding opening 293 or the accommodating groove 294 is generally greater than or equal to the size of the pressure relief mechanism 24, so as to reduce the blockage of the avoiding opening 293 or the accommodating groove 294 to the pressure relief mechanism 24, so that the pressure relief mechanism 24 can be actuated in time when the battery monomer 20 is in thermal runaway.

[0395] It should be understood that the material of the partition 29 of the embodiment of the present application can be set according to actual application. For example, the partition 29 is usually an insulating material. For another example, the material of the partition 29 includes plastic, so as to reduce cost and facilitate processing.

[0396] It should be understood that the fixing manner of the partition 29 in the embodiments of the present application can be set according to actual application. For example, the partition 29 is fixed to the wall portion 213 by an adhesive, which is simple to operate and easy to implement, and the structure is stable, reducing the risk of mutual misalignment between the partition 29 and the wall portion 213, or even the falling of the partition 29.

[0397] Referring again to FIG. 18, in some embodiments, along the thickness direction of the wall portion 213, the pressure relief mechanism 24 does not exceed the surface of the wall portion 213 farthest from the electrode assembly 23 in the direction away from the electrode assembly 23.

[0398] Along the thickness direction of the wall portion 213, the wall portion 213 has oppositely arranged inner and outer surfaces, wherein the inner surface faces the electrode assembly 23, and the outer surface faces away from the electrode assembly 23. The outer surface can be the surface of the wall portion 213 farthest from the electrode assembly 23.

[0399] When the pressure relief mechanism 24 does not exceed the surface of the wall portion 213 farthest from the electrode assembly 23 in the direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can be flush with the surface of the wall portion 213 farthest from the electrode assembly 23, or the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can be closer to the electrode assembly 23 than the surface of the wall portion 213 farthest from the electrode assembly 23.

[0400] By making the pressure relief mechanism 24 not exceed the surface of the wall portion 213 farthest from the electrode assembly 23 in the thickness direction of the wall portion 213, on the one hand, the occupation of the internal space of the battery device 100 can be reduced, which is conducive to improving the energy density of the battery device 100. On the other hand, the pressure relief mechanism 24 is less likely to interfere with other components and be affected by external forces, which is conducive to reducing the risk of the weak portion 2421 being damaged prematurely and improving the service life of the battery monomer 20.

[0401] Referring to FIG. 23, which is a structural schematic view of the wall portion 213 provided with an electrode terminal 25 according to some embodiments of the present application. In other embodiments, the battery monomer 20 further includes an electrode terminal 25, which is arranged on the wall portion 213 and at least partially protrudes from the wall portion 213 in the direction away from the electrode assembly 23. Along the thickness direction of the wall portion 213, the pressure relief mechanism 24 does not exceed the surface of the electrode terminal 25 farthest from the electrode assembly 23 in the direction away from the electrode assembly 23.

[0402] The electrode terminal 25 is used to electrically connect with the tab 232 of the electrode assembly 23 to input or output the electric energy of the battery monomer 20. The electrode terminal 25 can be directly connected with the tab 232, for example, the electrode terminal 25 is directly welded with the tab 232. The electrode terminal 25 can also be indirectly connected with the tab 232, for example, the electrode terminal 25 is indirectly connected with the tab 232 through a current collecting member. The electrode terminal 25 can be insulatedly arranged on the wall portion 213 and at least partially protrude from the outer surface of the wall portion 213.

[0403] When the pressure relief mechanism 24 does not exceed the surface of the electrode terminal 25 farthest away from the electrode assembly 23 in the direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 farthest away from the electrode assembly 23 can be flush with the surface of the electrode terminal 25 farthest away from the electrode assembly 23, or the surface of the pressure relief mechanism 24 farthest away from the electrode assembly 23 can be closer to the electrode assembly 23 than the surface of the electrode terminal 25 farthest away from the electrode assembly 23.

[0404] By making the pressure relief mechanism 24 not exceed the surface of the electrode terminal 25 farthest away from the electrode assembly 23 in the thickness direction of the wall portion 213, on the one hand, the occupation of the internal space of the battery device 100 can be reduced, which is beneficial to improve the energy density of the battery device 100. On the other hand, the pressure relief mechanism 24 is less likely to interfere with other components and be affected by external forces, which is beneficial to reduce the risk of the weak portion 2421 being damaged in advance and improve the service life of the battery monomer 20.

[0405] Please refer to FIG. 5, FIG. 6 and FIG. 7 again. In some embodiments, the weak portion 2421 is in a closed ring shape, and the thickness of the weak portion 2421 is the same at different positions.

[0406] The weak portion 2421 is in a ring structure, and the weak portion 2421 can be in a circular ring shape or an elliptical ring shape.

[0407] “The thickness of the weak portion 2421 is the same at different positions” means that the thickness of the cross section of the weak portion 2421 at any two positions in the extension direction of the weak portion 2421 is equal.

[0408] By making the weak portion 2421 in a closed ring shape and the thickness of the weak portion 2421 being the same at different positions, when the pressure inside the shell 21 reaches a threshold value, the pressure relief mechanism 24 can crack along the entire circumference of the weak portion 2421, so that the body portion 2422 can be separated from the pressure relief mechanism 24, and the body portion 2422 is less likely to hang on the second portion 2411 and block the gas eruption, which reduces the risk of high-temperature gas being sprayed to adjacent battery monomers 20 and improves the reliability of the battery monomer 20.

[0409] Please refer to FIG. 24 and FIG. 25, FIG. 24 is a top view of the pressure relief mechanism 24 according to some embodiments of the present application. FIG. 25 is a cross-sectional view of the position E-E in FIG. 24. In some embodiments, the weak portion 2421 is in a closed loop shape. The weak portion 2421 includes a first weak section 24212 and a second weak section 24213 connected end to end, and the thickness of the second weak section 24213 is greater than the thickness of the first weak section 24212. The second weak section 24213 is located on one side of the weak portion 2421 in the length direction of the wall portion 213.

[0410] The first weak section 24212 functions as a pressure relief, and is configured to allow the pressure relief mechanism 24 to split along at least a portion of the first weak section 24212 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, to release the pressure inside the battery cell 20.

[0411] The second weak section 24213 functions to guide the turning of at least a portion of the body portion 2422 to open. The second weak section 24213 has a higher strength than the first weak section 24212. When the battery cell 20 is relieved of pressure, the first weak section 24212 splits first to allow the fluid medium inside the battery cell 20 to flow out. Then, the body portion 2422 can turn outward with the second weak section 24213 as the turning axis under the action of the fluid medium, to open a larger opening and achieve rapid pressure relief.

[0412] Please refer to FIG. 24, the first weak section 24212 includes a first section 24212a, a second section 24212b, and a third section 24212c, the first section 24212a and the third section 24212c are oppositely arranged, one end of the second section 24212b is connected to one end of the first section 24212a, and the other end of the second section 24212b is connected to one end of the third section 24212c. The second weak section 24213 connects the other end of the first section 24212a and the other end of the third section 24212c. The first section 24212a, the second section 24212b, the third section 24212c, and the second weak section 24213 together define the body portion 2422.

[0413] Please refer to FIG. 24, the length direction of the wall portion 213 is the Y direction shown in the figure.

[0414] The second weak section 24213 is located on one side of the weak portion 2421 in the length direction of the wall portion 213, please refer to FIG. 24, the left-right direction is the length direction of the wall portion 213, at this time, the second weak section 24213 is located on the left side of the weak portion 2421. In this way, when the battery cell 20 is relieved of pressure, even if the body portion 2422 does not fully open, the high-temperature gas sprayed out will diffuse toward the length direction of the wall portion 213 under the action of the body portion 2422, that is, the high-temperature gas sprayed out is less likely to spray toward another battery cell 20 adjacent to it.

[0415] By setting the second weak section 24213, the strength of the pressure relief mechanism 24 at the position of the second weak section 24213 is weakened, so that the body part 2422 is more easily turned open under the action of the internal gas pressure of the battery monomer 20, not only can improve the probability of opening of the body part 2422, but also can improve the opening speed of the body part 2422, realize rapid pressure relief, reduce the risk of explosion and fire of the battery monomer 20, and is beneficial to improve the reliability of the battery monomer 20. By making the second weak section 24213 located on one side of the weak part 2421 in the length direction of the wall part 213, when the battery monomer 20 is pressure relieved, even if the body part 2422 is not completely opened, the high-temperature gas sprayed will diffuse towards the length direction of the wall part 213 under the action of the body part 2422, that is, the high-temperature gas sprayed is not easy to be directed to the other battery monomer 20 adjacent to it, and is not easy to cause thermal runaway of the other battery monomer 20, which is beneficial to improve the reliability of the battery device 100.

[0416] Please refer to FIG. 26, which is a top view of the pressure relief mechanism 24 provided by some embodiments of the present application. In some embodiments, the weak part 2421 is in the shape of an opening, and the opening end of the weak part 2421 is located on one side of the weak part 2421 in the length direction of the wall part 213.

[0417] The weak part 2421 can be in the shape of C, U, etc. with an opening at one end. The opening end of the weak part 2421 is located on one side of the weak part 2421 in the length direction of the wall part 213. Please refer to FIG. 26, the left-right direction is the length direction of the wall part 213, at this time, the opening end of the weak part 2421 is located on the left side of the weak part 2421. In this way, when the battery monomer 20 is pressure relieved, even if the body part 2422 is not completely opened, the high-temperature gas sprayed will diffuse towards the length direction of the wall part 213 under the action of the body part 2422, that is, the high-temperature gas sprayed is not easy to be directed to the other battery monomer 20 adjacent to it.

[0418] By making the opening end of the weak part 2421 located on one side of the weak part 2421 in the length direction of the wall part 213, when the battery monomer 20 is pressure relieved, even if the body part 2422 is not completely opened, the high-temperature gas sprayed will diffuse towards the length direction of the wall part 213 under the action of the body part 2422, that is, the high-temperature gas sprayed is not easy to be directed to the other battery monomer 20 adjacent to it, and is not easy to cause thermal runaway of the other battery monomer 20, which is beneficial to improve the reliability of the battery device 100.

[0419] Please refer to FIG. 6, FIG. 7 and FIG. 8 again, in some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, and the bottom wall of the pressure relief groove 245 forms the weak part 2421.

[0420] The weak part 2421 is formed on the pressure relief mechanism 24 by opening a pressure relief groove 245 on the pressure relief mechanism 24. When the battery monomer 20 is relieved, the pressure relief mechanism 24 is broken along at least part of the weak part 2421, which is simple, convenient, and low in cost.

[0421] Optionally, the pressure relief groove 245 is formed by stamping.

[0422] The pressure relief groove 245 is formed by stamping, which makes it easier to control the thickness of the weak part 2421 and has higher processing precision, which is beneficial to keeping the burst pressure of the plurality of battery monomers 20 consistent when manufacturing the plurality of battery monomers 20 and is beneficial to improving the reliability of the battery monomer 20.

[0423] Please refer to FIGS. 6, 7, and 8. In some embodiments, the cross section of the pressure relief groove 245 is trapezoidal or conical.

[0424] When the cross section of the pressure relief groove 245 is trapezoidal or conical, it is beneficial to quickly open the pressure relief of the body part 2422 when the battery monomer 20 is in thermal runaway.

[0425] Please refer to FIGS. 6, 7, and 8. In some embodiments, along the width direction of the pressure relief groove 245, the pressure relief groove 245 includes two oppositely arranged groove side surfaces 2452, and the angle b of the two groove side surfaces 2452 satisfies: 30°≤b≤90°.

[0426] Please refer to FIG. 8. The width direction of the pressure relief groove 245 is the N direction shown in the figure.

[0427] b represents the included angle of the two groove side surfaces 2452. The included angle of the two groove side surfaces 2452 can be: b=30°, 35°, 40°, 45°, b=50°, 55°, 60°, 65°, b=70°, 75°, 80°, 85°, 90°, etc.

[0428] When b≥30°, the pressure relief groove 245 can be conveniently stamped, reducing the processing difficulty of the pressure relief groove 245 and thus reducing the manufacturing cost of the battery monomer 20. When b≤90°, the material extrusion can be reduced. Therefore, when 30°≤b≤90°, both the manufacturing cost of the battery monomer 20 and the material extrusion can be reduced.

[0429] Optionally, 40°≤b≤80°.

[0430] The included angle of the two groove side surfaces 2452 can be: b=40°, 42°, 45°, 48°, b=50°, 52°, 55°, 58°, 60°, 62°, 65°, 68°, b=70°, 72°, 75°, 78°, 80°, etc.

[0431] When b ≥ 40°, the pressure relief groove 245 can be stamped more easily, reducing the processing difficulty of the pressure relief groove 245 and thus further reducing the manufacturing cost of the battery cell 20. When b ≤ 80°, the extrusion can be further reduced. Therefore, when 40° ≤ b ≤ 80°, both the manufacturing cost of the battery cell 20 and the extrusion can be reduced.

[0432] In some embodiments, the pressure relief mechanism 24 is separately disposed from the wall portion 213, the wall portion 213 is provided with a pressure relief hole 2131, and the pressure relief mechanism 24 is installed on the wall portion 213 and covers the pressure relief hole 2131.

[0433] The phrase "pressure relief mechanism 24 and wall portion 213 are separately provided, wall portion 213 is provided with pressure relief hole 2131, and pressure relief mechanism 24 is installed on wall portion 213 and covers pressure relief hole 2131" means that during manufacturing, pressure relief hole 2131 is provided on wall portion 213, and pressure relief mechanism 24 and wall portion 213 are provided separately and ultimately connected together. For example, pressure relief mechanism 24 can be welded to wall portion 213. Pressure relief mechanism 24 can be an explosion-proof plate installed on wall portion 213.

[0434] In some embodiments, a pressure relief mechanism 24 is disposed at one end of the pressure relief hole 2131 facing the electrode assembly 23. The battery cell 20 includes a protective member 26 disposed at one end of the pressure relief hole 2131 away from the electrode assembly 23 and covering the pressure relief hole 2131.

[0435] The pressure relief mechanism 24 is separately set and installed on the wall portion 213 to facilitate manufacturing.

[0436] In other embodiments, the pressure relief mechanism 24 is integrally formed with the wall portion 213.

[0437] One-piece molding means that the wall portion 213 and the pressure relief mechanism 24 are provided as a single structure. For example, the pressure relief mechanism 24 can be formed on the wall portion 213 by means of stamping or cold forging.

[0438] The pressure relief mechanism 24 is integrally formed with the wall portion 213, eliminating the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism 24. Furthermore, during production, it is easier to ensure that the detonation pressure of multiple battery cells 20 produced is more consistent.

[0439] Referring to FIG. 5, FIG. 6 and FIG. 7, the embodiments of the present application further provide a pressure relief mechanism 24 for the battery monomer 20. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421 configured to be at least partially destroyed to release pressure when the pressure inside the battery monomer 20 reaches a threshold value, a body portion 2422 located in the area surrounded by the weak portion 2421, and a connecting portion 241 located outside the weak portion 2421. The part of the body portion 2422 close to the weak portion 2421 is a first portion 24221, and the part of the connecting portion 241 close to the weak portion 2421 is a second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends in the thickness direction of the pressure relief mechanism 24 relative to the weak portion 2421.

[0440] Referring to FIG. 27, FIG. 27 is a schematic block diagram of a pressure relief mechanism manufacturing method 30 provided by some embodiments of the present application. The embodiments of the present application further provide a pressure relief mechanism manufacturing method 30 for the pressure relief mechanism 24 of the battery monomer 20. The pressure relief mechanism manufacturing method 30 includes:

[0441] Step S100: providing a sheet, the base material of the sheet being iron;

[0442] Step S200: processing a weak portion 2421 on the sheet, the weak portion 2421 being configured to be at least partially destroyed to release pressure when the pressure inside the battery monomer 20 reaches a threshold value. The part of the sheet located in the area surrounded by the weak portion 2421 is a body portion 2422, and the part of the sheet located outside the area surrounded by the weak portion 2421 is a connecting portion 241.

[0443] The part of the body portion 2422 close to the weak portion 2421 is a first portion 24221, and the part of the connecting portion 241 close to the weak portion 2421 is a second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends in the thickness direction of the sheet relative to the weak portion 2421.

[0444] Referring to FIG. 28, FIG. 28 is a schematic block diagram of a pressure relief mechanism manufacturing method 30 provided by some other embodiments of the present application. In some other embodiments, before step S200, the pressure relief mechanism manufacturing method 30 further includes:

[0445] Step S150: stamping the sheet to form a groove on the sheet;

[0446] Step S200 includes:

[0447] Step S210: processing a weak portion 2421 on the groove bottom wall to make the second portion 2411 extend in the thickness direction of the sheet relative to the weak portion 2421.

[0448] After step S210, the groove side wall is the second part 2411 of the pressure relief mechanism 24.

[0449] By first processing the groove on the sheet, and then processing the weak part 2421 on the groove bottom wall, the second part 2411 can extend along the thickness direction of the sheet relative to the weak part 2421, which is simple and convenient.

[0450] Please refer to FIG. 29, which is a schematic block diagram of a manufacturing method 30 of the pressure relief mechanism provided by some embodiments of the present application. In some other embodiments, step S200 includes:

[0451] Step S220: stamping the sheet to process the weak part 2421 on the sheet.

[0452] By processing the weak part 2421 by stamping, the thickness of the weak part 2421 can be more easily controlled, and the processing precision is higher, which is beneficial to keeping the burst pressure of the plurality of battery monomers 20 consistent when manufacturing the plurality of battery monomers 20, and is beneficial to improving the reliability of the battery monomer 20.

[0453] Optionally, in step S220, the flow direction of the sheet is controlled so that the first part 24221 extends along the thickness direction of the sheet relative to the weak part 2421.

[0454] In step S220, the flow direction of the sheet can be controlled by the support to make the first part 24221 extend along the thickness direction of the sheet relative to the weak part 2421.

[0455] By controlling the flow direction of the sheet when stamping the weak part 2421, the first part 24221 can extend along the thickness direction of the sheet relative to the weak part 2421, which is simple and convenient.

[0456] Embodiments of the present application also provide a battery device 100, which includes the battery monomer 20 described above.

[0457] Embodiments of the present application also provide a power consumption device, which includes the battery monomer 20 described above, and the battery monomer 20 is used to provide electric energy for the power consumption device.

[0458] According to some embodiments of the present application, please refer to FIGS. 3-26.

[0459] The embodiment of the present application provides a battery monomer 20, the battery monomer 20 includes a shell 21, an electrode assembly 23 and a pressure relief mechanism 24, the shell 21 has a wall part 213, the base material of the wall part 213 is iron, and the electrode assembly 23 is contained in the shell 21. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak part 2421, a body part 2422 and a connecting part 241, the weak part 2421 is configured to be at least partially destroyed to release pressure when the pressure inside the shell 21 reaches a threshold value, the body part 2422 is located in the area surrounded by the weak part 2421, and the connecting part 241 is located outside the weak part 2421 and is connected to the wall part 213. The part of the body part 2422 close to the weak part 2421 is a first part 24221, the part of the connecting part 241 close to the weak part 2421 is a second part 2411, and at least one of the first part 24221 and the second part 2411 extends relative to the weak part 2421 in the direction close to or away from the electrode assembly 23. By extending at least one of the first part 24221 and the second part 2411 relative to the weak part 2421 in the direction close to or away from the electrode assembly 23, the flow of material is facilitated when the weak part 2421 is punched and formed, which is beneficial to improve the stress of the weak part 2421, so that the formed weak part 2421 has good structural stability and is not easy to have a concave-convex wavy structure, which is beneficial to keep the burst pressure of the plurality of battery monomers 20 consistent when the plurality of battery monomers 20 are manufactured, and is beneficial to improve the reliability of the battery monomer 20. Furthermore, when the battery monomer 20 expands, the wall part 213 is deformed under stress, and at least one of the first part 24221 and the second part 2411 extended relative to the weak part 2421 can be stretched under external force, so as to reduce the pulling of the weak part 2421 by the external force, reduce the risk of the weak part 2421 being destroyed in advance, and improve the service life and reliability of the battery monomer 20.

[0460] The first portion 24221 and the second portion 2411 are both extended relative to the weakened portion 2421 in a direction away from the electrode assembly 23. When the first portion 24221 and the second portion 2411 are both extended relative to the weakened portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 is allowed to extend with the extension height of the second portion 2411, thereby facilitating reduction of the height of the body portion 2422 beyond the surface of the connecting portion 241 farthest from the electrode assembly 23, reduction of the occupation of the internal space of the battery device 100, and improvement of the energy density of the battery device 100. In addition, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 respectively apply forces in opposite directions to the weakened portion 2421, so that the weakened portion 2421 is subjected to a shearing force, facilitating the opening of the weakened portion 2421 for depressurization. Under the same burst pressure, the thickness of the weakened portion 2421 can be greater, and the weakened portion 2421 is less likely to be prematurely cracked due to changes in the pressure inside the battery cell 20 or external impact when the battery cell 20 is normally used, thereby facilitating reduction of the risk of premature damage of the weakened portion 2421 and improvement of the service life of the battery cell 20.

[0461] The preferred embodiments of the present application have been described above with the aid of drawings and are not intended to limit the scope of the application. Various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A battery cell, wherein, The application relates to a battery, comprising: a shell having a wall portion, a base material of the wall portion being iron; an electrode assembly accommodated in the shell; a pressure relief mechanism, a base material of the pressure relief mechanism being iron, the pressure relief mechanism comprising a weak portion, a body portion and a connecting portion, the weak portion being configured to be at least partially destroyed to release pressure when the pressure inside the shell reaches a threshold value, the body portion being located in an area surrounded by the weak portion, the connecting portion being located outside the weak portion and connected to the wall portion, a part of the body portion close to the weak portion being a first portion, a part of the connecting portion close to the weak portion being a second portion, at least one of the first portion and the second portion extending relative to the weak portion in a direction close to or away from the electrode assembly.

2. The battery cell of claim 1, wherein, A difference between a surface roughness of the first portion and a surface roughness of the weak portion is less than or equal to Ra0.3, and / or A difference between a surface roughness of the second portion and a surface roughness of the weak portion is less than or equal to Ra0.

3.

3. The battery cell of claim 2, wherein, The surface roughness of the weak portion, the surface roughness of the first portion and the surface roughness of the second portion are the same.

4. The battery cell of any one of claims 1-3, wherein, The pressure relief mechanism is provided with a pressure relief groove, a bottom wall of the pressure relief groove forming the weak portion; A groove side surface of the pressure relief groove and a groove bottom surface of the pressure relief groove are connected through a round corner; and / or The pressure relief mechanism comprises a first surface, the pressure relief groove is arranged on the first surface, and the groove side surface of the pressure relief groove is connected to the first surface through a round corner.

5. The battery cell of any one of claims 1-4, wherein, The material of the wall portion comprises at least one of stainless steel and carbon steel; and the material of the pressure relief mechanism comprises at least one of stainless steel and carbon steel.

6. The battery cell of claim 5, wherein, The material of the wall portion comprises at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel; and the material of the pressure relief mechanism comprises at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel.

7. The battery cell of any one of claims 1-6, wherein, The thickness of the body portion is H1, and 0.05mm<=H1<=0.5mm is satisfied; and / or The thickness of the connecting portion is H2, and 0.05mm<=H2<=0.5mm is satisfied.

8. The battery cell of any one of claims 1-7, wherein, The extension height of at least one of the first portion and the second portion extending relative to the weak portion is in a range of [0.2mm, 7mm].

9. The battery cell of claim 8, wherein, The extension height of at least one of the first portion and the second portion extending relative to the weak portion is in a range of [0.3mm, 5mm].

10. The battery cell of any one of claims 1-9, wherein, The first portion at least partially extends relative to the weak portion in a direction close to or away from the electrode assembly.

11. The battery cell of claim 10, wherein, The first portion entirely extends relative to the weak portion in a direction away from the electrode assembly.

12. The battery cell of claim 10, wherein, Part of the first portion extends relative to the weak portion in a direction away from the electrode assembly.

13. The battery cell of any one of claims 10-12, wherein, The electrode assembly comprises at least two layers of electrode sheets; The at least two layers of electrode sheets are arranged in a stacking mode, and the stacking direction of the at least two layers of electrode sheets is a first direction; or the at least two layers of electrode sheets are arranged in a winding mode, and the at least two layers of electrode sheets each comprise a planar section located in a middle portion of the electrode assembly and a curved section located at two ends of the electrode assembly, and the stacking direction of the at least two layers of electrode sheets in the planar section is the first direction. The body part is arched in a cross section perpendicular to the first direction.

14. The battery cell of any one of claims 10-13, wherein, The first part extends relative to the weak part by an extension height H3, which satisfies: 0.5mm≤H3≤5mm.

15. The battery cell of claim 14, wherein, 0.8mm≤H3≤3mm.

16. The battery cell of any one of claims 1-9, wherein, The second part extends relative to the weak part in a direction close to or away from the electrode assembly.

17. The battery cell of claim 16, wherein, The connecting part includes a third part for connecting with the wall part, and the second part connects the weak part and the third part.

18. The battery cell of claim 17, wherein, The third part is parallel to the wall part.

19. The battery cell of claim 17 or 18, wherein, The second part is arranged obliquely relative to the third part, and an oblique angle of the second part relative to the third part is a, which satisfies: 40°≤a≤75°.

20. The battery cell of any one of claims 1-19, wherein, The first part and the second part both extend relative to the weak part, and a direction in which the first part extends relative to the weak part is the same as a direction in which the second part extends relative to the weak part.

21. The battery cell of claim 20, wherein, The first part and the second part both extend relative to the weak part in a direction close to the electrode assembly.

22. The battery cell of claim 20, wherein, The first part and the second part both extend relative to the weak part in a direction away from the electrode assembly.

23. The battery cell of any one of claims 1-19, wherein, The first part and the second part both extend relative to the weak part, and a direction in which the first part extends relative to the weak part is opposite to a direction in which the second part extends relative to the weak part.

24. The battery cell of claim 23, wherein, The first part extends relative to the weak part in a direction close to the electrode assembly, and the second part extends relative to the weak part in a direction away from the electrode assembly.

25. The battery cell of claim 23, wherein, The first part extends relative to the weak part in a direction away from the electrode assembly, and the second part extends relative to the weak part in a direction close to the electrode assembly.

26. The battery cell of any one of claims 1-25, wherein, A minimum thickness of the weak part is H4, which satisfies: 0.01mm≤H4≤0.2mm.

27. The battery cell of claim 26, wherein, A projection area of the body part along a thickness direction of the wall part is S. wherein 100 mm 2 ≤ 450 mm 2 and 0.010 mm ≤ H4≤ 0.160 mm; or, 350 mm 2 ≤ S ≤ 850 mm 2 and 0.015 mm ≤ H4 ≤ 0.170 mm; or, 750 mm 2 ≤ S ≤ 1250 mm 2 and 0.020 mm ≤ H4≤ 0.180 mm; or, 1150 mm 2 ≤ S ≤ 1650 mm 2 and 0.025 mm ≤ H4≤ 0.190 mm; or, 1550 mm 2 ≤ S ≤ 2100 mm 2 and 0.030 mm ≤ H4≤ 0.200 mm.

28. The battery cell of claim 27, wherein, 100 mm 2 ≤ S ≤ 450 mm 2 and 0.020 mm ≤ H4≤ 0.160 mm; or, 350 mm 2 ≤ S ≤ 850 mm 2 and 0.025 mm ≤ H4≤ 0.170 mm; or, 750 mm 2 ≤ S ≤ 1250 mm 2 and 0.030 mm ≤ H4≤ 0.180 mm; or, 1150 mm 2 ≤ S ≤ 1650 mm 2 and 0.035 mm ≤ H4≤ 0.190 mm; or, 1550 mm 2 ≤ S ≤ 2100 mm 2 and 0.040 mm ≤ H4≤ 0.200 mm.

29. The battery cell of any one of claims 1-28, wherein, The connecting part is welded to the wall part.

30. The battery cell of claim 29, wherein, The battery monomer further includes: A support structure is fixed to a side of the wall part facing the electrode assembly, the pressure relief mechanism is located on a side of the support structure away from the electrode assembly, the connecting part is welded to the support structure, and a base material of the support structure is iron.

31. The battery cell of claim 30, wherein, The support structure and the wall part are fixed by welding or by adhesion.

32. The battery cell of claim 30 or 31, wherein, In a direction close to the electrode assembly, the pressure relief mechanism does not exceed a surface of the support structure facing the electrode assembly.

33. The battery cell of any one of claims 30-32, wherein, A thickness of the support structure is H5, which satisfies: 0.4mm≤H5≤1.5mm.

34. The battery cell of claim 33, wherein, 0.4mm≤H5≤0.8mm.

35. The battery cell of any one of claims 30-34, wherein, The pressure relief mechanism, the wall part, and the support structure are connected by a same welding seam.

36. The battery cell of any one of claims 1-35, wherein, The battery monomer further includes: A partition is arranged on a side of the wall part facing the electrode assembly, and in a direction close to the electrode assembly, the pressure relief mechanism at least partially protrudes from a surface of the wall part facing the electrode assembly, and the partition protrudes from a surface of the pressure relief mechanism facing the electrode assembly.

37. The battery cell of claim 36, wherein, The partition comprises a fourth part and a fifth part arranged at intervals, and the pressure relief mechanism is located between the fourth part and the fifth part.

38. The battery cell of claim 36, wherein, The partition is provided with an avoiding opening for avoiding the pressure relief mechanism.

39. The battery cell of claim 36, wherein, The partition is provided with a containing groove with an opening facing the pressure relief mechanism, the containing groove is used for containing the pressure relief mechanism, the bottom of the containing groove is provided with a thinned area corresponding to the pressure relief mechanism, and the thickness of the thinned area is less than the thickness of other areas of the bottom of the containing groove.

40. The battery cell of any one of claims 1-39, wherein, In the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the wall portion farthest away from the electrode assembly in the direction away from the electrode assembly.

41. The battery cell of any one of claims 1-39, wherein, The battery monomer further comprises an electrode terminal arranged on the wall portion, and the electrode terminal at least partially protrudes from the wall portion in the direction away from the electrode assembly. In the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the electrode terminal farthest away from the electrode assembly in the direction away from the electrode assembly.

42. The battery cell of any one of claims 1-41, wherein, The weak part is in a closed ring shape, and the thickness of the weak part is the same at each position.

43. The battery cell of any one of claims 1-41, wherein, The weak part is in a closed ring shape, and the weak part comprises a first weak segment and a second weak segment connected in a head-to-tail manner, the thickness of the second weak segment is greater than the thickness of the first weak segment, and the second weak segment is located on one side of the weak part in the length direction of the wall portion.

44. The battery cell of any one of claims 1-41, wherein, The weak part is in an open shape, and the open end of the weak part is located on one side of the weak part in the length direction of the wall portion.

45. The battery cell of any one of claims 1-44, wherein, The pressure relief mechanism is provided with a pressure relief groove, and the bottom wall of the pressure relief groove forms the weak part.

46. The battery cell of claim 45, wherein, The pressure relief groove is formed by stamping.

47. The battery cell of claim 45 or 46, wherein, The cross section of the pressure relief groove is in a trapezoidal or conical shape.

48. The battery cell of any one of claims 45-47, wherein, In the width direction of the pressure relief groove, the pressure relief groove comprises two groove side surfaces arranged oppositely, and the angle of the two groove side surfaces is b, which satisfies: 30°≤b≤90°, and optionally, 40°≤b≤80°.

49. A pressure relief mechanism for a battery cell, wherein, The base material of the pressure relief mechanism is iron, the pressure relief mechanism comprises a weak part, a body part and a connecting part, the weak part is configured to be at least partially destroyed to release the pressure when the pressure inside the battery monomer reaches a threshold value, the body part is located in the area surrounded by the weak part, the connecting part is located outside the weak part, a part of the body part close to the weak part is a first part, a part of the connecting part close to the weak part is a second part, and at least one of the first part and the second part extends relative to the weak part in the thickness direction of the pressure relief mechanism.

50. A method of manufacturing a pressure relief mechanism for a battery cell, wherein, The pressure relief mechanism manufacturing method comprises: Step S100: providing a blank, and the base material of the blank is iron; Step S200: processing a weak part on the blank, the weak part is used for being at least partially destroyed to release the pressure when the pressure inside the battery monomer reaches a threshold value, the part of the blank located in the area surrounded by the weak part is a body part, and the part of the blank located outside the area surrounded by the weak part is a connecting part; At least one of the first portion and the second portion extends relative to the weak portion in a thickness direction of the web.

51. The method of manufacturing a pressure relief mechanism of claim 50, wherein, Before the step S200, the pressure relief mechanism manufacturing method further comprises: Step S150: stamping the web to form a groove on the web; The step S200 comprises: Step S210: processing the weak portion on a groove bottom wall of the groove, so that the second portion extends relative to the weak portion in a thickness direction of the web.

52. The pressure relief mechanism manufacturing method of claim 50 or 51, wherein, The step S200 comprises: Step S220: stamping the web to process the weak portion on the web.

53. The method of manufacturing a pressure relief mechanism of claim 52, wherein, In the step S220, a flow direction of the web is controlled so that the first portion extends relative to the weak portion in a thickness direction of the web.

54. A battery device, wherein, A battery cell according to any one of claims 1-48.

55. An electrical device, comprising: A battery cell according to any one of claims 1-48, the battery cell being configured to provide electrical energy to the electrical device.

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