Battery monomer, pressure relief mechanism, battery and electric equipment

Abstract

The utility model provides a battery monomer, a pressure relief mechanism, a battery and electric equipment. The battery monomer comprises a shell, an electrode assembly and a pressure relief mechanism, the shell is provided with a wall part, and the wall part is provided with a pressure relief hole. The electrode assembly is housed within the housing. The pressure relief mechanism covers the pressure relief hole, and the base material of the pressure relief mechanism is iron. The pressure relief mechanism comprises a weak part, a protruding part and a connecting part, and the weak part is configured to be at least partially damaged to release pressure when the pressure in the shell reaches a threshold value. The weak part is annular, the protruding part is located in an area defined by the weak part, and the connecting part is located on the outer side of the weak part and connected with the wall part. The protruding part is of a protruding structure protruding in the direction away from the electrode assembly. The minimum thickness H1 of the weak portion satisfies 0.01 mm < = H1 < = 0.2 mm. The protruding part forms pre-deformation on the inner side of the weak part, so that the weak part is convenient to crack and release pressure. Under the same bursting pressure, the thickness of the weak part can be larger, and the weak part is not easy to crack in advance due to stress, so that the service life of the single battery is prolonged.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a battery cell, a pressure relief mechanism, a battery, and an electrical device. Background Art

[0002] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery life must be considered. However, current batteries have a relatively short lifespan. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a pressure relief mechanism, a battery and an electrical device, which are intended to improve the problem of short battery life in the related art.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, which includes a shell, an electrode assembly and a pressure relief mechanism, the shell having a wall portion, the wall portion being provided with a pressure relief hole; the electrode assembly being accommodated in the shell; the pressure relief mechanism covering the pressure relief hole, the base material of the pressure relief mechanism being iron, the pressure relief mechanism including a weak portion, a raised portion and a connecting portion, the weak portion being configured to be at least partially destroyed to release the pressure when the pressure inside the shell reaches a threshold value, the weak portion being annular, the raised portion being located within the area enclosed by the weak portion, the connecting portion being located outside the weak portion and connected to the wall portion, the raised portion being a raised structure raised in a direction away from the electrode assembly, the minimum thickness of the weak portion being H1, satisfying 0.01mm≤H1≤0.2mm.

[0005] In the above-mentioned technical solution, the conventional pressure relief mechanism gradually arches from a flat plate structure away from the electrode assembly during pressure relief under the influence of internal pressure in the battery cell. After arching, it then opens to release pressure under the influence of internal pressure in the battery cell. In contrast, in the present embodiment, the raised portion of the pressure relief mechanism rises away from the electrode assembly, creating a pre-deformation inside the weak portion, thereby facilitating the rupture of the weak portion to release pressure. This allows the thickness of the weak portion to be greater under the same burst pressure. During normal use of the battery cell, the weak portion is less likely to rupture prematurely due to pressure fluctuations within the battery cell or external impacts, thereby reducing the risk of premature damage and improving the life of the battery cell. When H1 ≥ 0.01 mm, the thickness of the weak portion is greater, making it less likely to rupture prematurely due to pressure fluctuations within the battery cell or external impacts, thereby reducing the risk of premature damage and improving the life of the battery cell. When H1 ≤ 0.2 mm, the thickness of the weak portion is not excessive, allowing the pressure relief mechanism to open and release pressure promptly in the event of thermal runaway, thereby improving the timeliness of the pressure relief mechanism's pressure relief. Therefore, when 0.01mm ≤ H1 ≤ 0.2mm, both the battery cell lifespan and timely pressure relief are achieved. Furthermore, the iron base material of the pressure relief mechanism effectively enhances its structural strength, reduces the risk of deformation due to stress, and reduces the risk of premature valve opening, thereby improving the battery cell lifespan and reliability. Compared to aluminum explosion-proof valves in the prior art, the pressure relief mechanism provided in the present embodiment has a smaller thickness at the weak portion. During manufacturing, even a slight change in the thickness of the weak portion can significantly alter the burst pressure of the battery cell. By providing a raised portion, the thickness of the weak portion can be increased under the same burst pressure. A thicker weak portion is easier to manufacture, thus facilitating consistent burst pressure across multiple battery cells. Furthermore, when a battery cell expands, the wall deforms under stress, and the raised portion stretches under external force, thereby reducing the pull of external forces on the weak portion and reducing the risk of premature failure, thereby improving the battery cell lifespan.

[0006] As an optional technical solution of the embodiment of the present application, the boundary of the raised portion is at least partially adjacent to the boundary of the weak portion.

[0007] In the above technical solution, by making the boundary of the raised portion at least partially adjacent to the boundary of the weak portion, when the battery cell is depressurized, the raised portion can directly pull the weak portion through the adjacent portion, so that the portion of the weak portion adjacent to the boundary of the raised portion is subjected to a greater shear force, thereby facilitating the opening of the weak portion to release pressure. Under the condition of the same blasting pressure, the thickness of the weak portion can be greater. When the battery cell is in normal use, the weak portion is less likely to crack prematurely due to pressure changes within the battery cell or external impact, which is beneficial to reducing the risk of premature damage to the weak portion and improving the life of the battery cell. In addition, the thicker the weak portion, the easier it is to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells.

[0008] As an optional technical solution of the embodiment of the present application, the boundary of the raised portion is completely adjacent to the boundary of the weak portion.

[0009] In the above technical solution, by ensuring that the boundary of the raised portion is completely adjacent to the boundary of the weak portion, the raised portion can directly pull on the weak portion when the battery cell is depressurized, subjecting the weak portion to a greater shear force, thereby facilitating the opening of the weak portion to release pressure. Under the same blasting pressure, the thickness of the weak portion can be increased. During normal use of the battery cell, the weak portion is less likely to crack prematurely due to pressure changes within the battery cell or external impacts, thereby reducing the risk of premature damage to the weak portion and improving the life of the battery cell. Furthermore, a thicker weak portion is easier to manufacture, thereby facilitating the consistency of the detonation pressure across multiple battery cells.

[0010] As an optional technical solution of the embodiment of the present application, the area enclosed by the weak portion is a pressure relief zone, and the projected area of ​​the pressure relief zone along the thickness direction of the wall portion is S;

[0011] Among them, 100mm 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or,

[0012] 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or,

[0013] 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or,

[0014] 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or,

[0015] 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

[0016] In the above technical solution, when the projected area of ​​the pressure relief zone is larger, the pressure relief zone is more susceptible to the internal pressure and the weak part is cracked. Therefore, when the projected area of ​​the pressure relief zone increases, in order to ensure the same blasting pressure, the thickness of the weak part can be increased. 2 ≤S≤450mm 2 , and when H1≥0.010mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.010mm≤H1≤0.160mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0017] When 350mm 2 ≤S≤850mm 2 , and when H1≥0.015mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2 , and when 0.015mm≤H1≤0.170mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0018] When 750mm 2 ≤S≤1250mm 2 , and when H1≥0.020mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.020mm≤H1≤0.180mm, both the service life of the battery cell and the timeliness of pressure release can be taken into account.

[0019] When 1150mm 2 ≤S≤1650mm 2 , and when H1≥0.025mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.025mm≤H1≤0.190mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0020] When 1550mm 2 ≤S≤2100mm 2 , and when H1≥0.030mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.030mm≤H1≤0.200mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0021] As an optional technical solution of the embodiment of this application, 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or,

[0022] 350mm2 ≤S≤850mm 2 , and 0.025mm≤H1≤0.170mm; or,

[0023] 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or,

[0024] 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or,

[0025] 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

[0026] In the above technical solution, when 100mm 2 ≤S≤450mm 2 , and when H1≥0.020mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.020mm≤H1≤0.160mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0027] When 350mm 2 ≤S≤850mm 2 , and when H1≥0.025mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2, and when 0.025mm≤H1≤0.170mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0028] When 750mm 2 ≤S≤1250mm 2 , and when H1≥0.030mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.030mm≤H1≤0.180mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0029] When 1150mm 2 ≤S≤1650mm 2 , and when H1≥0.035mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.035mm≤H1≤0.190mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0030] When 1550mm 2 ≤S≤2100mm 2 , and when H1≥0.040mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤2100mm 2, and when H1≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.040mm≤H1≤0.200mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0031] As an optional technical solution of the embodiment of the present application, the raised height of the raised portion is H2, which satisfies: 0.2mm≤H2≤4.9mm.

[0032] In the above technical solution, when H2 ≥ 0.2mm, the height of the raised portion is higher. As a result, the deformation of the raised portion is more obvious. Under the same blasting pressure, the thickness of the weak portion is greater, which helps reduce the risk of premature damage to the weak portion and helps improve the life of the battery cell. When H2 ≤ 4.9mm, the height of the raised portion is not too large. On the one hand, it helps to reduce the internal space occupied by the battery or battery cell and improve the energy density of the battery or battery cell. On the other hand, it helps to reduce the risk of interference between the raised portion and other components. Therefore, when 0.2mm ≤ H2 ≤ 4.9mm, it can take into account both the life and energy density of the battery cell and reduce the risk of interference between the raised portion and other components.

[0033] As an optional technical solution of the embodiment of the present application, 0.3mm≤H2≤3mm.

[0034] In the above technical solution, when H2 ≥ 0.3mm, the height of the raised portion is higher, so that the deformation of the raised portion is more obvious. Under the same blasting pressure, the thickness of the weak portion can be greater, which helps reduce the risk of premature damage to the weak portion and helps improve the life of the battery cell. When H2 ≤ 3mm, the height of the raised portion is not too large. On the one hand, it helps to reduce the internal space occupied by the battery or battery cell and improve the energy density of the battery or battery cell. On the other hand, it helps to reduce the risk of interference between the raised portion and other components. Therefore, when 0.3mm ≤ H2 ≤ 3mm, it is possible to better balance the life and energy density of the battery cell and reduce the risk of interference between the raised portion and other components.

[0035] As an optional technical solution of an embodiment of the present application, the raised portion includes an arc-shaped portion extending along an arc-shaped trajectory, and along the extension direction of the arc-shaped trajectory, the arc-shaped portion includes a first end and a second end, and the first end and the second end are arranged along a first direction, and the first direction is parallel to the thickness direction of the wall with the largest outer surface area of ​​the shell.

[0036] In the above technical solution, when a battery cell expands, the wall with the largest outer surface area of ​​the housing deforms the most. By configuring the raised portion to include an arc extending along an arcuate trajectory, and with the first direction parallel to the thickness direction of the wall with the largest outer surface area of ​​the housing, the raised portion is more easily stretched by external forces when the battery cell expands, thereby further reducing the external force pulling on the weak portion, lowering the risk of premature damage to the weak portion, and thus improving the life of the battery cell.

[0037] As an optional technical solution of an embodiment of the present application, the connecting portion is a flat plate structure, and the weak portion directly connects the connecting portion and the raised portion.

[0038] In the above technical solution, the connecting portion is a flat plate structure, which makes it more convenient to connect the connecting portion to the wall portion. The weak portion is directly connected to the connecting portion and the raised portion. When the battery cell is depressurized, the raised portion can directly pull the weak portion, so that the shear force on the weak portion is greater, thereby facilitating the opening of the weak portion to release pressure. Under the same blasting pressure, the thickness of the weak portion can be larger. When the battery cell is in normal use, the weak portion is not likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reducing the risk of premature damage to the weak portion and improving the life of the battery cell. In addition, the thicker the weak portion, the easier it is to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells.

[0039] As an optional technical solution of an embodiment of the present application, the connecting portion at least partially bulges in a direction away from the electrode assembly, and the weak portion is connected to a portion of the connecting portion farthest from the electrode assembly.

[0040] In the above technical solution, by making the connecting part at least partially bulge in the direction away from the electrode assembly and connecting the weak part to the part of the connecting part farthest from the electrode assembly, when the connecting part is connected to the wall, it is not easy to affect the weak part, which is beneficial to maintaining the performance of the weak part and improving the life of the battery cell.

[0041] As an optional technical solution of an embodiment of the present application, the connecting portion is at least partially raised in a direction facing the electrode assembly, and the weak portion is connected to a portion of the connecting portion closest to the electrode assembly.

[0042] In the above technical solution, the connecting portion at least partially rises in a direction facing the electrode assembly, and the raised portion rises in a direction away from the electrode assembly. The rising direction of the connecting portion is opposite to the rising direction of the raised portion, so that the raised portion can rise using the rising height of the connecting portion, thereby facilitating the reduction of the height of the raised portion beyond the surface of the connecting portion farthest from the electrode assembly, reducing the space occupied by the internal battery cell or battery, and facilitating the improvement of the energy density of the battery cell or battery. In addition, because the weak portion is connected to the portion of the connecting portion closest to the electrode assembly, that is, the weak portion is located closer to the electrode assembly than the location of the fixing point between the connecting portion and the wall portion, and because one end of the connecting portion is constrained by the wall portion, under the action of air pressure, the portion of the connecting portion that rises in the direction facing the electrode assembly squeezes the weak portion, thereby suppressing cracking of the weak portion and preventing creep failure of the weak portion during normal operation of the battery cell, effectively extending the life of the battery cell.

[0043] As an optional technical solution of an embodiment of the present application, part of the connecting portion is inclined toward the interior of the shell; in the cross section of the connecting portion, the angle between the inclined portion of the connecting portion and the thickness direction of the wall portion is a, satisfying: 30°≤a≤70°.

[0044] In the above technical solution, when a ≥ 30°, the inclination of the connection is large, which effectively constrains the weak part and helps reduce the risk of creep failure of the weak part. When a ≤ 70°, the inclination of the connection is not too large, which helps reduce stress concentration and the risk of brittle fracture.

[0045] As an optional technical solution of an embodiment of the present application, the raised height of the connecting portion is H3, which satisfies: 0.2mm≤H3≤7mm, optionally, 0.2mm≤H3≤5mm.

[0046] In the above technical solution, when H3 ≥ 0.2mm, the height of the raised portion of the connection is relatively large, which helps reduce the height of the raised portion exceeding the surface of the connection portion farthest from the electrode assembly, reduces the space occupied by the battery cell or battery interior, and helps improve the energy density of the battery cell or battery. When H3 ≤ 7mm, the height of the raised portion of the connection is not too large, which helps reduce the manufacturing difficulty and save manufacturing costs. Therefore, when 0.2mm ≤ H3 ≤ 7mm, it can effectively reduce the space occupied by the raised portion of the battery cell or battery interior, and reduce the manufacturing cost of the battery cell.

[0047] When H3 ≥ 0.2mm, the height of the raised portion of the connection is relatively large, which helps reduce the height of the raised portion beyond the surface of the connection portion farthest from the electrode assembly, reducing the space occupied by the battery cell or battery interior, and helping to improve the energy density of the battery cell or battery. When H3 ≤ 5mm, the height of the raised portion of the connection is not too large, which is more conducive to reducing manufacturing difficulty and saving manufacturing costs. Therefore, when 0.2mm ≤ H3 ≤ 5mm, it can effectively reduce the space occupied by the raised portion of the battery cell or battery interior, and reduce the manufacturing cost of the battery cell.

[0048] As an optional technical solution of an embodiment of the present application, along the thickness direction of the wall portion, the connecting portion has a first surface farthest from the electrode assembly, and the raised portion does not exceed the first surface in a direction away from the electrode assembly.

[0049] In the above technical solution, by ensuring that the raised portion does not extend beyond the first surface in a direction away from the electrode assembly, on the one hand, the internal space occupied by the battery cell or battery can be reduced, which is beneficial for improving the energy density of the battery cell or battery. On the other hand, the raised portion is less susceptible to external forces, which helps reduce the risk of premature damage to the weak portion and improves the life of the battery cell.

[0050] As an optional technical solution of an embodiment of the present application, along the thickness direction of the wall portion, the raised portion does not exceed the outer surface of the wall portion in a direction away from the electrode assembly.

[0051] In the above technical solution, by ensuring that the raised portion does not extend beyond the outer surface of the wall in the direction away from the electrode assembly, on the one hand, the internal space occupied by the battery can be reduced, which is beneficial for improving the battery's energy density. On the other hand, the raised portion is less likely to interfere with other components and is less susceptible to external forces, which helps reduce the risk of premature damage to weak parts and improves the life of the battery cells.

[0052] As an optional technical solution of an embodiment of the present application, along the thickness direction of the wall portion, the connecting portion has a first surface farthest from the electrode assembly, the battery cell includes an electrode terminal, the electrode terminal is arranged on the wall portion and at least partially protrudes from the outer surface of the wall portion, and the electrode terminal has a second surface facing away from the electrode assembly; along the thickness direction of the wall portion, the raised portion extends beyond the first surface along the direction from the second surface to the first surface, and does not extend beyond the second surface.

[0053] In the above technical solution, by making the raised portion extend beyond the first surface in a direction away from the electrode assembly, deformation of the raised portion is more pronounced. Under the same burst pressure, the thickness of the weak portion can be increased, which helps reduce the risk of premature failure of the weak portion and improves the life of the battery cell. By making the raised portion not extend beyond the second surface in a direction away from the electrode assembly, the risk of interference with other electrical connection components is reduced.

[0054] As an optional technical solution of an embodiment of the present application, the battery cell includes an electrode terminal, which is arranged on the wall portion and at least partially protrudes from the outer surface of the wall portion, and the electrode terminal has a second surface facing away from the electrode assembly; along the thickness direction of the wall portion, the raised portion does not exceed the second surface in the direction facing away from the electrode assembly.

[0055] In the above technical solution, by ensuring that the raised portion does not extend beyond the second surface in a direction away from the electrode assembly, the risk of interference between the raised portion and other electrical connection components is reduced.

[0056] As an optional technical solution of an embodiment of the present application, the battery cell includes an insulating member, which is arranged between the wall portion and the electrode assembly along the thickness direction of the wall portion; along the thickness direction of the wall portion, the insulating member is closer to the electrode assembly than the pressure relief mechanism.

[0057] In the above technical solution, by providing an insulating member between the wall and the electrode assembly, the wall and the electrode assembly can be insulated and isolated, reducing the risk of short circuits caused by contact between the wall and the electrode assembly. By placing the insulating member closer to the electrode assembly than the pressure relief mechanism, the risk of contact between the electrode assembly and the pressure relief mechanism can be reduced, and a fluid channel can be left between the electrode assembly and the pressure relief mechanism, thereby facilitating pressure relief.

[0058] As an optional technical solution of the embodiment of the present application, the material of the pressure relief mechanism is 304 stainless steel, 305 stainless steel or 316 stainless steel.

[0059] In the above technical solution, 304 stainless steel, 305 stainless steel and 316 stainless steel have the advantages of corrosion resistance, high temperature resistance and good processing performance. The pressure relief mechanism made of 304 stainless steel, 305 stainless steel or 316 stainless steel has high strength, which can reduce the risk of deformation of the pressure relief mechanism due to force, which is beneficial to reducing the risk of premature valve opening and pressure relief of the pressure relief mechanism, which is beneficial to improving the service life and reliability of battery cells and improving the consistency of the detonation pressure of multiple battery cells.

[0060] 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 position of the pressure relief mechanism corresponding to the pressure relief groove forms the weak portion.

[0061] In the above technical solution, a weak portion is formed on the pressure relief mechanism by providing a pressure relief groove on the pressure relief mechanism. When the battery cell releases pressure, the pressure relief mechanism is cracked along at least a portion of the weak portion, which is simple, convenient and low-cost.

[0062] As an optional technical solution of the embodiment of the present application, the cross-section of the pressure relief groove is trapezoidal or conical.

[0063] In the above technical solution, when the cross-section of the pressure relief groove is trapezoidal or conical, it is beneficial for the pressure relief zone to quickly open and relieve pressure when the battery cell experiences thermal runaway.

[0064] As an optional technical solution of an embodiment of the present application, along the width direction of the pressure relief groove, the pressure relief groove includes two groove side surfaces arranged opposite to each other, and the angle between the two groove side surfaces is b, satisfying: 30°≤b≤90°, optionally, 40°≤b≤80°.

[0065] In the above technical solution, when b ≥ 30°, the pressure relief groove can be easily punched out, reducing the processing difficulty of the pressure relief groove and thus reducing the manufacturing cost of the battery cell. When b ≤ 90°, it can reduce material extrusion. Therefore, when 30° ≤ b ≤ 90°, it can reduce both the manufacturing cost of the battery cell and the extrusion of material.

[0066] When b ≥ 40°, the pressure relief groove can be punched out more easily, reducing the difficulty of processing the pressure relief groove, thereby further reducing the manufacturing cost of the battery cell. When b ≤ 80°, it can further reduce material extrusion. Therefore, when 40° ≤ b ≤ 80°, it can reduce both the manufacturing cost of the battery cell and the extrusion of material.

[0067] As an optional technical solution of an embodiment of the present application, the weak portion includes a first weak section and a second weak section, the first weak section and the second weak section are connected end to end, and the thickness of the first weak section is less than the thickness of the second weak section.

[0068] In the above technical solution, by setting a second weak section, the strength of the pressure relief mechanism at the second weak section is weakened, making it easier for the pressure relief area to flip open under the action of the internal air pressure of the battery cell. This not only increases the probability of the pressure relief area opening, but also increases the opening speed of the pressure relief area, thereby achieving rapid pressure relief and reducing the risk of explosion and fire of the battery cell, which is beneficial to improving the reliability of the battery cell.

[0069] As an optional technical solution of an embodiment of the present application, along the extension direction of the second weak section, the second weak section includes a third end and a fourth end, the line connecting the third end and the fourth end is a first line, and the angle between the first line and the thickness direction of the wall with the largest outer surface area of ​​the shell is C, satisfying: 0≤C≤45°.

[0070] In the above technical solution, when 0≤C≤45°, the angle between the first connecting line and the wall with the largest outer surface area of ​​the shell in the thickness direction is relatively small. When the battery cell is depressurized, even if the pressure relief zone is not fully opened, the ejected high-temperature gas and / or flame is not likely to be directed toward another adjacent battery cell, and is not likely to cause thermal runaway of another battery cell, which is beneficial to improving the reliability of the battery.

[0071] As an optional technical solution of an embodiment of the present application, the first connecting line is parallel to the thickness direction of the wall of the outer surface of the shell with the largest area.

[0072] In the above technical solution, the first connecting line is parallel to the thickness direction of the wall with the largest outer surface area of ​​the shell. When the battery cell is depressurized, even if the pressure relief zone is not fully opened, the ejected high-temperature gas and / or flame is not likely to be directed toward another adjacent battery cell, and is not likely to cause thermal runaway of another battery cell, which is beneficial to improving the reliability of the battery.

[0073] As an optional technical solution of an embodiment of the present application, the second weak section extends along an arc trajectory.

[0074] In the above technical solution, when the second weak section extends along the arc trajectory, the area of ​​the pressure relief zone is larger, which facilitates opening a larger opening for pressure relief.

[0075] As an optional technical solution of an embodiment of the present application, the second weak section extends along a straight line.

[0076] In the above technical solution, when the second weak section extends along a straight line, it is easy to process and has a better effect of guiding the pressure relief area to flip.

[0077] As an optional technical solution of an embodiment of the present application, the minimum thickness of the second weak section is H4, which satisfies: 0.05mm≤H4≤0.2mm, optionally, 0.05mm≤H4≤0.15mm.

[0078] In the above technical solution, when H4 ≥ 0.05mm, the thickness of the second weak section is relatively large, which can reduce the risk of the second weak section cracking due to changes in air pressure inside the battery cell or external impact, which is beneficial to improving the reliability of the battery cell. When H4 ≤ 0.2mm, the thickness of the second weak section is not too large, which is beneficial to reducing the resistance to the flipping of the pressure relief zone, facilitating the rapid flipping and opening of the pressure relief zone, and is beneficial to improving the timeliness of the pressure relief of the battery cell. Therefore, when 0.05mm ≤ H4 ≤ 0.2mm, the thickness of the second weak section is moderate, and the second weak section is not easily cracked due to changes in air pressure inside the battery cell or external impact, and is convenient for the rapid flipping and opening of the pressure relief zone, which is beneficial to improving the timeliness of the pressure relief of the battery cell.

[0079] When H4 ≥ 0.05mm, the thickness of the second weak section is relatively large, which can reduce the risk of the second weak section cracking due to changes in air pressure inside the battery cell or external impact, which is beneficial to improving the reliability of the battery cell. When H4 ≤ 0.15mm, the thickness of the second weak section is not too large, which is more conducive to reducing the resistance to the flipping of the pressure relief zone, facilitating the rapid flipping and opening of the pressure relief zone, and is more conducive to improving the timeliness of the pressure relief of the battery cell. Therefore, when 0.05mm ≤ H4 ≤ 0.2mm, the thickness of the second weak section is moderate, and the second weak section is not easily cracked due to changes in air pressure inside the battery cell or external impact, and is convenient for the rapid flipping and opening of the pressure relief zone, which is beneficial to improving the timeliness of the pressure relief of the battery cell.

[0080] As an optional technical solution of an embodiment of the present application, the thickness of the pressure relief mechanism is H5, which satisfies: 0.05mm≤H5≤0.5mm, optionally, 0.05mm≤H5≤0.3mm.

[0081] In the above technical solution, when H5 ≥ 0.05mm, the pressure relief mechanism is thicker, providing greater structural strength, reducing the risk of deformation due to stress, and thus improving the battery cell's service life and reliability. When H5 ≤ 0.5mm, the pressure relief mechanism is not excessively thick, helping to control the manufacturing cost of the battery cell. Therefore, when 0.05mm ≤ H5 ≤ 0.5mm, the battery cell's service life, reliability, and manufacturing cost are balanced.

[0082] When H5 ≥ 0.05mm, the pressure relief mechanism is thicker, providing greater structural strength and reducing the risk of deformation due to stress, thereby improving the battery cell's service life and reliability. When H5 ≤ 0.3mm, the pressure relief mechanism is not excessively thick, further helping to control battery cell manufacturing costs. Therefore, when 0.05mm ≤ H5 ≤ 0.3mm, a better balance is achieved between battery cell service life, reliability, and manufacturing costs.

[0083] As an optional technical solution of an embodiment of the present application, the base material of the wall portion is iron, and the pressure relief mechanism is welded to the wall portion.

[0084] In the above technical solution, the base materials of the pressure relief mechanism and the wall are both iron. On the one hand, this can effectively improve the structural strength of the wall and pressure relief mechanism, reduce the risk of deformation due to stress on the wall and pressure relief mechanism, and help reduce the risk of premature valve opening and pressure relief of the pressure relief mechanism, thereby improving the service life and reliability of the battery cells. On the other hand, it is easier to weld the pressure relief mechanism and the wall, which helps to reduce the phenomenon of welding cracks between the pressure relief mechanism and the end cap, thereby reducing the risk of leakage in the battery cells and improving the reliability of the battery cells.

[0085] In the second aspect, an embodiment of the present application further provides a pressure relief mechanism, the base material of the pressure relief mechanism is iron, the pressure relief mechanism includes a weak portion, a raised portion and a connecting portion, the weak portion is configured to be at least partially destroyed when the battery cell is depressurized, the weak portion is annular, the raised portion is located in the area surrounded by the weak portion, the connecting portion is located on the outside of the weak portion, the raised portion is a raised structure raised along the thickness direction of the pressure relief mechanism, the minimum thickness of the weak portion is H1, satisfying 0.01mm≤H1≤0.2mm.

[0086] As an optional technical solution of the embodiment of the present application, the area enclosed by the weak portion is a pressure relief area, and the projected area of ​​the pressure relief area along the thickness direction of the pressure relief mechanism is S;

[0087] Among them, 100mm 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or,

[0088] 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or,

[0089] 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or,

[0090] 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or,

[0091] 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

[0092] In the above technical solution, when the projected area of ​​the pressure relief zone is larger, the pressure relief zone is more susceptible to the internal pressure and the weak part is cracked. Therefore, when the projected area of ​​the pressure relief zone increases, in order to ensure the same blasting pressure, the thickness of the weak part can be increased. 2 ≤S≤450mm 2 , and when H1≥0.010mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.010mm≤H1≤0.160mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0093] When 350mm 2 ≤S≤850mm 2 , and when H1≥0.015mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2 , and when 0.015mm≤H1≤0.170mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0094] When 750mm 2 ≤S≤1250mm 2 , and when H1≥0.020mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤1250mm 2, and when H1≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.020mm≤H1≤0.180mm, both the service life of the battery cell and the timeliness of pressure release can be taken into account.

[0095] When 1150mm 2 ≤S≤1650mm 2 , and when H1≥0.025mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.025mm≤H1≤0.190mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0096] When 1550mm 2 ≤S≤2100mm 2 , and when H1≥0.030mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.030mm≤H1≤0.200mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0097] As an optional technical solution of the embodiment of this application, 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or,

[0098] 350mm 2 ≤S≤850mm2 , and 0.025mm≤H1≤0.170mm; or,

[0099] 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or,

[0100] 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or,

[0101] 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

[0102] In the above technical solution, when 100mm 2 ≤S≤450mm 2 , and when H1≥0.020mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.02mm≤H1≤0.160mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0103] When 350mm 2 ≤S≤850mm 2 , and when H1≥0.025mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2 , and when 0.025mm≤H1≤0.170mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0104] When 750mm 2 ≤S≤1250mm 2 , and when H1≥0.030mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.030mm≤H1≤0.180mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0105] When 1150mm 2 ≤S≤1650mm 2 , and when H1≥0.035mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.035mm≤H1≤0.190mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0106] When 1550mm 2 ≤S≤2100mm 2 , and when H1≥0.040mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2, and when 0.040mm≤H1≤0.200mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0107] As an optional technical solution of the embodiment of the present application, the raised height of the raised portion is H2, which satisfies: 0.2mm≤H2≤4.9mm.

[0108] In the above technical solution, when H2 ≥ 0.2mm, the height of the raised portion is higher. As a result, the deformation of the raised portion is more obvious. Under the same blasting pressure, the thickness of the weak portion is greater, which helps reduce the risk of premature damage to the weak portion and helps improve the life of the battery cell. When H2 ≤ 4.9mm, the height of the raised portion is not too large. On the one hand, it helps to reduce the internal space occupied by the battery or battery cell and improve the energy density of the battery or battery cell. On the other hand, it helps to reduce the risk of interference between the raised portion and other components. Therefore, when 0.2mm ≤ H2 ≤ 4.9mm, it can take into account both the life and energy density of the battery cell and reduce the risk of interference between the raised portion and other components.

[0109] As an optional technical solution of the embodiment of the present application, 0.3mm≤H2≤3mm.

[0110] In the above technical solution, when H2 ≥ 0.3mm, the height of the raised portion is higher, so that the deformation of the raised portion is more obvious. Under the same blasting pressure, the thickness of the weak portion can be greater, which helps reduce the risk of premature damage to the weak portion and helps improve the life of the battery cell. When H2 ≤ 3mm, the height of the raised portion is not too large. On the one hand, it helps to reduce the internal space occupied by the battery or battery cell and improve the energy density of the battery or battery cell. On the other hand, it helps to reduce the risk of interference between the raised portion and other components. Therefore, when 0.3mm ≤ H2 ≤ 3mm, it is possible to better balance the life and energy density of the battery cell and reduce the risk of interference between the raised portion and other components.

[0111] In a third aspect, an embodiment of the present application further provides a battery, which includes the above-mentioned battery cell.

[0112] As an optional technical solution of an embodiment of the present application, the battery includes a plurality of battery cells, and the plurality of battery cells are arranged along the second direction; the weak portion includes a first weak section and a second weak section, the first weak section and the second weak section are connected end to end, and the thickness of the first weak section is less than the thickness of the second weak section; along the extension direction of the second weak section, the second weak section includes a third end and a fourth end, the line connecting the third end and the fourth end is a first line, and the angle between the first line and the second direction is D, satisfying: 0≤D≤45°.

[0113] In the above technical solution, when 0≤D≤45°, the angle between the first connecting line and the second direction is relatively small. When the battery cell is depressurized, even if the pressure relief zone is not fully opened, the ejected high-temperature gas and / or flame is not likely to be directed toward another adjacent battery cell, and is not likely to cause thermal runaway of another battery cell, which is beneficial to improving the reliability of the battery.

[0114] As an optional technical solution of the embodiment of the present application, the first connecting line is parallel to the second direction.

[0115] In the above technical solution, the first connecting line is parallel to the second direction. When the battery cell is depressurized, even if the pressure relief zone is not fully opened, the ejected high-temperature gas and / or flame is unlikely to be directed toward another adjacent battery cell, and is unlikely to cause thermal runaway of another battery cell, which is beneficial to improving the reliability of the battery.

[0116] As an optional technical solution of an embodiment of the present application, the second direction is the thickness direction of the wall of the outer surface area of ​​the shell having the largest area.

[0117] In the above technical solution, by arranging the multiple battery cells along the thickness direction of the wall of the outer surface area of ​​the housing with the largest area, it is beneficial to fully utilize the space and improve the energy density of the battery.

[0118] In a fourth aspect, an embodiment of the present application further provides an electric device, wherein the electric device includes the above-mentioned battery cell, and the battery cell is used to provide electric energy for the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0120] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0121] Figure 2 An exploded view of a battery provided in accordance with some embodiments of the present application;

[0122] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0123] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0124] Figure 5A schematic top view of a wall portion provided in some embodiments of the present application;

[0125] Figure 6 for Figure 5 Cross-sectional view at the AA position;

[0126] Figure 7 Cross-sectional views of walls provided for other embodiments of the present application;

[0127] Figure 8 A schematic structural diagram of a pressure relief mechanism provided in some other embodiments of the present application;

[0128] Figure 9 A schematic top view of a pressure relief mechanism provided in some other embodiments of the present application;

[0129] Figure 10 for Figure 9 Cross-sectional view of the middle BB position;

[0130] Figure 11 A cross-sectional view of a pressure relief mechanism provided in some further embodiments of the present application;

[0131] Figure 12 A cross-sectional view of a pressure relief mechanism provided in some embodiments of the present application;

[0132] Figure 13 for Figure 10 Enlarged view of the middle C position;

[0133] Figure 14 Schematic diagram of the structure of the pressure relief mechanism provided in some other embodiments of the present application.

[0134] Icons: 10-case; 11-first part; 12-second part; 20-battery cell; 21-housing; 211-housing; 212-end cover; 213-wall; 2131-pressure relief hole; 23-electrode assembly; 231-main body; 232-ear; 24-pressure relief mechanism; 241-connecting part; 2411-first surface; 2421-weak part; 24212-first weak section; 24212a-first section; 24212b-second section; 242 12c-third section; 24213-second weak section; 24213a-third end; 24213b-fourth end; 2422-pressure relief area; 24221-raised portion; 24221a-arc-shaped portion; 24221b-first end; 24221c-second end; 245-pressure relief groove; 25-electrode terminal; 251-second surface; 26-protective member; 27-insulating member; 100-battery; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0135] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0136] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0137] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0138] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0139] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0140] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0141] The term "plurality" used in this application refers to two or more (including two).

[0142] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0143] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0144] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits to a certain extent while allowing the active ions to pass through.

[0145] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0146] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0147] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0148] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0149] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0150] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0151] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0152] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0153] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0154] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0155] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0156] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0157] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0158] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0159] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0160] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0161] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0162] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0163] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0164] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0165] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0166] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0167] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

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

[0169] In some embodiments, the electrode assembly is a laminate structure.

[0170] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0171] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0172] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0173] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0174] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0175] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0176] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0177] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0178] In some embodiments, the housing can be a sealed structure or a non-sealed structure. For example, when the housing is a sealed structure, the housing can protect the electrode assembly and, to a certain extent, prevent leakage of the electrolyte. When the housing is a non-sealed structure, the housing can also protect the electrode assembly. A sealing bag can be included between the housing and the electrode assembly to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0179] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0180] The battery mentioned 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.

[0181] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0182] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0183] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0184] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0185] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0186] The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery life must be considered. However, current batteries have a relatively short lifespan.

[0187] For battery cells, in order to improve the reliability of battery cells, the existing technology is to set a pressure relief mechanism on the battery cells. A weak part is set on the pressure relief mechanism. When the internal pressure of the battery cell reaches the bursting pressure, the weak part cracks to release the pressure inside the battery cell, thereby reducing the risk of battery cell explosion and fire.

[0188] However, in existing technologies, the thinness of the weak portion makes it susceptible to premature rupture due to pressure fluctuations within the battery cell or external impacts. This means that the weak portion can rupture before the internal pressure of the battery cell reaches the desired burst pressure, leading to premature failure and a shortened battery life. Simply increasing the thickness of the weak portion would increase the burst pressure, increasing the risk of thermal runaway in the battery cell.

[0189] In view of this, an embodiment of the present application provides a battery cell, which includes a shell, an electrode assembly and a pressure relief mechanism. The shell has a wall portion, and the wall portion is provided with a pressure relief hole. The electrode assembly is accommodated in the shell, and the pressure relief mechanism covers the pressure relief hole. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion, a raised portion and a connecting portion. The weak portion is configured to be at least partially destroyed to release pressure when the pressure inside the shell reaches a threshold. The weak portion is annular, the raised portion is located in the area surrounded by the weak portion, and the connecting portion is located on the outside of the weak portion and connected to the wall portion. The raised portion is a raised structure that rises in a direction away from the electrode assembly. The minimum thickness of the weak portion is H1, which satisfies 0.01mm≤H1≤0.2mm.

[0190] Conventional pressure relief mechanisms gradually bulge from a flat plate structure away from the electrode assembly during pressure relief under the influence of internal pressure within the battery cell. After bulging, they then open to release pressure under the influence of internal pressure within the battery cell. In the present embodiment, however, the bulge of the pressure relief mechanism bulges away from the electrode assembly, creating a pre-deformation inside the weak portion, thereby facilitating the rupture of the weak portion to release pressure. This allows for a greater thickness of the weak portion under the same burst pressure. During normal battery cell use, the weak portion is less likely to rupture prematurely due to internal pressure fluctuations or external impacts, thus reducing the risk of premature damage and improving the battery cell's lifespan. When H1 ≥ 0.01 mm, the thickness of the weak portion is greater, making it less likely to rupture prematurely due to internal pressure fluctuations or external impacts, thus reducing the risk of premature damage and improving the battery cell's lifespan. When H1 ≤ 0.2 mm, the thickness of the weak portion is not excessively large, allowing the pressure relief mechanism to open promptly to release pressure in the event of thermal runaway, thus improving the timeliness of the pressure relief mechanism's pressure relief. Therefore, when 0.01mm ≤ H1 ≤ 0.2mm, both the battery cell lifespan and timely pressure relief are achieved. Furthermore, the iron base material of the pressure relief mechanism effectively enhances its structural strength, reduces the risk of deformation due to stress, and reduces the risk of premature valve opening, thereby improving the battery cell lifespan and reliability. Compared to aluminum explosion-proof valves in the prior art, the pressure relief mechanism provided in the present embodiment has a smaller thickness at the weak portion. During manufacturing, even a slight change in the thickness of the weak portion can significantly alter the burst pressure of the battery cell. By providing a raised portion, the thickness of the weak portion can be increased under the same burst pressure. A thicker weak portion is easier to manufacture, thus facilitating consistent burst pressure across multiple battery cells. Furthermore, when a battery cell expands, the wall deforms under stress, and the raised portion stretches under external force, thereby reducing the pull of external forces on the weak portion and reducing the risk of premature failure, thereby improving the battery cell lifespan.

[0191] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0192] Electrically powered equipment may include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, and may include but are not limited to electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0193] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle 1000 as an example.

[0194] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0195] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0196] Please refer to Figure 2 , Figure 2 An exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 is used to provide a storage space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cells 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. The first portion 11 and the second portion 12 can also be hollow structures with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0197] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0198] Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may 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 may be cylindrical, flat, rectangular, or in other shapes.

[0199] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 , Figure 3 This is a schematic structural diagram of a battery cell 20 provided in some embodiments of the present application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application. Figure 5 This is a schematic top view of the wall portion 213 provided in some embodiments of the present application. Figure 6 for Figure 5 Cross-sectional view at the AA position in the middle. An embodiment of the present application provides a battery cell 20, which includes a shell 21, an electrode assembly 23 and a pressure relief mechanism 24. The shell 21 has a wall portion 213, and the wall portion 213 is provided with a pressure relief hole 2131. The electrode assembly 23 is accommodated in the shell 21, and the pressure relief mechanism 24 covers the pressure relief hole 2131. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421, a raised portion 24221 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 shell 21 reaches a threshold value. The weak portion 2421 is annular, and the raised portion 24221 is located in the area enclosed by the weak portion 2421. The connecting portion 241 is located outside the weak portion 2421 and connected to the wall portion 213. The raised portion 24221 is a raised structure raised in a direction away from the electrode assembly 23 . The minimum thickness of the weak portion 2421 is H1 , satisfying 0.01 mm ≤ H1 ≤ 0.2 mm.

[0200] The battery cell 20 refers to the smallest unit constituting the battery 100 .

[0201] The housing 21 includes a shell 211 and an end cap 212. The shell 211 has an accommodation space with one end open, and the accommodation space is used to accommodate the electrode assembly 23. The end cap 212 is connected to the shell 211 and closes the opening.

[0202] The end cap 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 cap 212 can be adapted to the shape of the shell 211 to match the shell 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the end cap 212 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved reliability. The material of the end cap 212 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The end cap 212 is also provided with an electrode terminal 25, which is used to electrically connect to the tab 232 of the electrode assembly 23 to input or output 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 may also be indirectly connected. For example, the electrode terminal 25 and the tab 232 are indirectly connected via a current collecting member.

[0203] The housing 211 is a component that cooperates with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 211 and end cap 212 can be separate components. An opening can be provided in the housing 211, and the end cap 212 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and housing 211 can be integrated. Specifically, the end cap 212 and housing 211 can form a common joint surface before other components are inserted into the housing. When the interior of the housing 211 needs to be enclosed, the end cap 212 is placed over the housing 211. The housing 211 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined based on the specific shape and size of the electrode assembly 23. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0204] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 211. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active materials constitute the main body 231 of the electrode assembly 23, and the portions of the positive and negative electrode sheets without active materials each constitute a tab 232. The positive tab and the negative tab may be located together at one end of the main body 231 or respectively at both ends of the main body 231. During the charge and discharge process of the battery 100, the positive active material and the negative active material react with the electrolyte.

[0205] The wall portion 213 may be the end cover 212 of the housing 21 or a wall of the shell 211 of the housing 21. Figure 3 and Figure 4 In the embodiment, the wall portion 213 is the end cap 212. In other embodiments, the wall portion 213 is the bottom wall of the housing 211 opposite to the end cap 212. In still other embodiments, the wall portion 213 may also be a side wall of the housing 211 adjacent to and connected to the end cap 212.

[0206] The pressure relief mechanism 24 is a component designed to release the internal pressure of the battery cell 20 when the internal pressure or temperature reaches the burst pressure. The pressure relief mechanism 24 is mounted on the wall portion 213. The pressure relief mechanism 24 is separate from and connected to the wall portion 213. During manufacturing, a pressure relief hole 2131 is formed in the wall portion 213. The pressure relief mechanism 24 and the wall portion 213 are provided separately and then 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 burst disk mounted on the wall portion 213. The location of the pressure relief mechanism 24 can be used to identify which wall of the housing 21 is the wall portion 213. For example, if the pressure relief mechanism 24 is mounted on the end cap 212, the end cap 212 is the wall portion 213. If the pressure relief mechanism 24 is mounted on the bottom wall of the housing 211, the bottom wall is the wall portion 213. When the pressure relief mechanism 24 is disposed on a side wall of the housing 211 , the side wall serves as the wall portion 213 .

[0207] "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.

[0208] The weak portion 2421 serves as a pressure relief mechanism, allowing the pressure relief mechanism 24 to rupture along at least a portion of the weak portion 2421 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, thereby releasing the pressure within the battery cell 20. In some embodiments, the strength of the pressure relief mechanism 24 at the weak portion 2421 can be lower than the strength of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of the internal pressure, thereby releasing the pressure within the battery cell 20. In other embodiments, the melting point of the pressure relief mechanism 24 at the weak portion 2421 can be lower than the melting point of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of high temperature, thereby releasing the pressure within the battery cell 20.

[0209] The weak portion 2421 is an annular structure, and can be circular or elliptical. The weak portion 2421 divides the pressure relief mechanism 24 into two parts, one part being located inside the weak portion 2421 and the other part being located outside the weak portion 2421 .

[0210] The raised portion 24221 is located inside the weak portion 2421 and is a raised structure that rises in a direction away from the electrode assembly 23. The raised structure has both inner and outer surfaces that arch in a direction away from the electrode assembly 23.

[0211] The connecting portion 241 is located outside the weak portion 2421 . The connecting portion 241 is a portion of the pressure relief mechanism 24 used to connect to the wall portion 213 . For example, the connecting portion 241 can be welded to the wall portion 213 .

[0212] Please refer to Figure 4 and Figure 6 , the thickness direction of the wall portion 213 is the X direction shown in the figure.

[0213] H1 represents the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 . During measurement, the thickness at different positions may be measured multiple times and the average value may be taken as H1 .

[0214] The minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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.

[0215] When releasing pressure, the existing pressure relief mechanism 24 will gradually arch from a flat plate structure in a direction away from the electrode assembly 23 under the action of the internal pressure of the battery cell 20. After arching, it will open and release pressure under the action of the internal pressure of the battery cell 20. In the embodiment of the present application, the raised portion 24221 of the pressure relief mechanism 24 rises in a direction away from the electrode assembly 23. The raised portion 24221 forms a pre-deformation on the inner side of the weak portion 2421, thereby facilitating the rupture of the weak portion 2421 to release pressure. In this way, under the same blasting pressure, the thickness of the weak portion 2421 can be larger. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to rupture prematurely due to pressure changes inside the battery cell 20 or external impacts, which helps to reduce the risk of premature damage to the weak portion 2421 and helps to increase the life of the battery cell 20. When H1≥0.01mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easy to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of the weak portion 2421 being damaged prematurely, and is beneficial to improving the life of the battery cell 20. When H1≤0.2mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 thermally runs away, which is beneficial to improving the timeliness of the pressure relief mechanism 24. Therefore, when 0.01mm≤H1≤0.2mm, the service life and timeliness of pressure relief of the battery cell 20 can be taken into account. In addition, the base material of the pressure relief mechanism 24 is iron, which can effectively improve the structural strength of the pressure relief mechanism 24, reduce the risk of deformation of the pressure relief mechanism 24 due to stress, and is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to release pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell 20. Compared to aluminum explosion-proof valves in the prior art, the thickness of the weak portion 2421 of the pressure relief mechanism 24 provided in the embodiment of the present application is smaller. During manufacturing, even a slight change in the thickness of the weak portion 2421 will significantly change the bursting pressure of the battery cell 20. By providing the raised portion 24221, the thickness of the weak portion 2421 can be increased under the same bursting pressure. The thicker the weak portion 2421, the easier it is to manufacture, which helps to improve the consistency of the bursting pressure of multiple battery cells 20. Furthermore, when the battery cell 20 expands, the wall portion 213 is deformed by the force, and the raised portion 24221 can be stretched under the action of external force, thereby reducing the pulling of the weak portion 2421 by external force, reducing the risk of premature damage to the weak portion 2421, and helping to improve the life of the battery cell 20.

[0216] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , Figure 7The cross-sectional view of the wall portion 213 is provided for some other embodiments of the present application. In some embodiments, the boundary of the raised portion 24221 is at least partially adjacent to the boundary of the weakened portion 2421.

[0217] “At least a portion of the boundary of the raised portion 24221 is adjacent to a portion of the boundary of the weak portion 2421 ” can also be understood as at least a portion of the boundary of the raised portion 24221 overlapping with a portion of the boundary of the weak portion 2421 . In other words, at least a portion of the weak portion 2421 is directly connected to the raised portion 24221 .

[0218] Please refer to Figure 7 ,exist Figure 7 In the figure, the right edge of the raised portion 24221 is adjacent to the edge of the weak portion 2421, that is, the right edge of the raised portion 24221 is directly connected to the weak portion 2421. The left edge of the raised portion 24221 is spaced apart from the edge of the weak portion 2421, that is, the left edge of the raised portion 24221 is spaced apart from the weak portion 2421.

[0219] By ensuring that the boundary of the raised portion 24221 is at least partially adjacent to the boundary of the weak portion 2421, when the battery cell 20 is depressurized, the raised portion 24221 can directly pull the weak portion 2421 through the adjacent portion, resulting in a greater shear force applied to the portion of the weak portion 2421 adjacent to the boundary of the raised portion 24221, thereby facilitating the opening of the weak portion 2421 to release pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely crack due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Furthermore, a thicker weak portion 2421 is easier to manufacture, thereby facilitating uniformity in the detonation pressure across multiple battery cells 20.

[0220] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , the boundary of the raised portion 24221 is completely adjacent to the boundary of the weak portion 2421 .

[0221] The phrase "the boundary of the raised portion 24221 at least partially abuts the boundary of the weak portion 2421" can also be understood as the boundary of the raised portion 24221 completely overlapping the boundary of the weak portion 2421. It should be noted that the weak portion 2421 has an inner boundary adjacent to the raised portion 24221 and an outer boundary surrounding the inner boundary. It is sufficient that the boundary of the raised portion 24221 completely overlaps the inner boundary of the weak portion 2421.

[0222] “At least a portion of the boundary of the raised portion 24221 is adjacent to the boundary of the weak portion 2421 ” can also be said to mean that each portion of the weak portion 2421 is directly connected to the raised portion 24221 .

[0223] Please refer to Figure 6 ,exist Figure 6 In the illustrated embodiment, both left and right ends of the raised portion 24221 are directly connected to the weakened portion 2421 .

[0224] By ensuring that the boundary of the raised portion 24221 is completely adjacent to the boundary of the weak portion 2421, the raised portion 24221 can directly pull on the weak portion 2421 when the battery cell 20 releases pressure, subjecting the weak portion 2421 to a greater shear force, thereby facilitating the opening of the weak portion 2421 and releasing pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely crack due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Furthermore, a thicker weak portion 2421 is easier to manufacture, thereby facilitating the consistency of the burst pressure across multiple battery cells 20.

[0225] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 and Figure 9 , Figure 8 Schematic diagram of the structure of the pressure relief mechanism 24 provided in some other embodiments of the present application. Figure 9 Schematic diagram of a top view of the pressure relief mechanism 24 provided in some other embodiments of the present application. In some embodiments, the area enclosed by the weak portion 2421 is the pressure relief area 2422. Along the thickness direction of the wall portion 213, the projected area of ​​the pressure relief area 2422 is S. 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or,

[0226] 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or,

[0227] 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or,

[0228] 1150mm 2 ≤S≤1650mm2 , and 0.025mm≤H1≤0.190mm; or,

[0229] 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

[0230] The pressure relief area 2422 is the area of ​​the pressure relief mechanism 24 enclosed by the weak portion 2421, i.e., the area of ​​the pressure relief mechanism 24 located inside the weak portion 2421. When the battery cell 20 releases pressure, the weak portion 2421 cracks along the edge of the pressure relief area 2422, allowing the pressure relief area 2422 to open and release pressure.

[0231] The pressure relief area 2422 includes the above-mentioned raised portion 24221. For example, the pressure relief area 2422 may be partially raised in a direction away from the electrode assembly 23 to form the raised portion 24221, or the pressure relief area 2422 may be raised as a whole in a direction away from the electrode assembly 23 to form the raised portion 24221. Figure 6 ,exist Figure 6 In the illustrated embodiment, the pressure relief area 2422 as a whole bulges in a direction away from the electrode assembly 23 to form a bulge 24221 . In this case, the pressure relief area 2422 is the bulge 24221 .

[0232] S represents the projected area of ​​the pressure relief zone 2422 along the thickness direction of the wall portion 213. Figure 9 , Figure 9 The S is marked with a mesh line. It should be noted that the mesh line here is only for the convenience of displaying S and does not represent any entity meaning.

[0233] The projected area of ​​the pressure relief zone 2422 along the thickness direction of the wall portion 213 can be: S = 100 mm 2 , 150mm 2 , 200mm 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.

[0234] When 100mm 2 ≤S≤450mm 2 When 0.010mm≤H1≤0.160mm. When 100mm 2 ≤S≤450mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.010mm, 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, etc.

[0235] When the projected area of ​​the pressure relief zone 2422 is larger, the pressure relief zone 2422 is more susceptible to the internal pressure and the weak portion 2421 is more likely to rupture. Therefore, when the projected area of ​​the pressure relief zone 2422 is increased, in order to ensure the same bursting pressure, the thickness of the weak portion 2421 can be increased. 2 <S≤450mm 2, and H1 ≥ 0.010mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.010mm≤H1≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0236] When 350mm 2 ≤S≤850mm 2 When 0.015mm≤H1≤0.170mm. When 350mm 2 ≤S≤850mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.015mm, 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, etc.

[0237] When 350mm 2 ≤S≤850mm 2 , and H1 ≥ 0.015mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.015mm≤H1≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0238] When 750mm2 ≤S≤1250mm 2 When 0.020mm≤H1≤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: H1 = 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.

[0239] When 750mm 2 ≤S≤1250mm 2 , and H1 ≥ 0.020mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.020mm≤H1≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0240] When 1150mm 2 ≤S≤1650mm 2 When 0.025mm≤H1≤0.190mm. When 1150mm 2 ≤S≤1650mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.025mm, 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.

[0241] When 1150mm 2 ≤S≤1650mm2 , and H1 ≥ 0.025mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.025mm≤H1≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0242] When 1550mm 2 ≤S≤2100mm 2 When 0.030mm≤H1≤0.200mm. When 1550mm 2 ≤S≤2100mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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.

[0243] When 1550mm 2 ≤S≤2100mm 2 , and H1 ≥ 0.030mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.030mm≤H1≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0244] In some embodiments, 100 mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or,

[0245] 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H1≤0.170mm; or,

[0246] 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or,

[0247] 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or,

[0248] 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

[0249] When 100mm 2 ≤S≤450mm 2 When 0.020mm≤H1≤0.160mm. When 100mm 2 ≤S≤450mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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.

[0250] When 100mm 2 <S≤450mm 2, and H1 ≥ 0.020mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.020mm≤H1≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0251] When 350mm 2 ≤S≤850mm 2 When 0.025mm≤H1≤0.170mm. When 350mm 2 ≤S≤850mm 2 When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1=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.

[0252] When 350mm 2 ≤S≤850mm 2 , and H1 ≥ 0.025mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2, and when H1≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.025mm≤H1≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0253] When 750mm 2 ≤S≤1250mm 2 When 0.030mm≤H1≤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: H1 = 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.

[0254] When 750mm 2 ≤S≤1250mm 2 , and H1 ≥ 0.030mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.030mm≤H1≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0255] When 1150mm 2≤S≤1650mm 2 When 0.035mm≤H1≤0.190mm. When 1150mm 2 ≤S≤1650mm 2 When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1=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.

[0256] When 1150mm 2 ≤S≤1650mm 2 , and H1 ≥ 0.035mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.035mm≤H1≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0257] When 1550mm 2 ≤S≤2100mm 2 When 0.040mm≤H1≤0.200mm. When 1550mm 2 ≤S≤2100mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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, 0.12 5mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 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, 0.195mm, 0.200mm, etc.

[0258] When 1550mm 2 ≤S≤2100mm 2 , and H1 ≥ 0.040mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.040mm≤H1≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0259] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 The raised height of the raised portion 24221 is H2, which satisfies: 0.2mm≤H2≤4.9mm.

[0260] H2 represents the height of the raised portion 24221. In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, and the position of the pressure relief mechanism 24 corresponding to the pressure relief groove 245 forms a weak portion 2421. Figure 6 and Figure 7When the pressure relief groove 245 is provided on the side of the pressure relief mechanism 24 facing away from the electrode assembly 23, the weak portion 2421 has a first surface facing the electrode assembly 23. The maximum distance from the first surface to the inner surface of the raised portion 24221 can be measured as H2. When the pressure relief groove 245 is provided on the side of the pressure relief mechanism 24 facing the electrode assembly 23, the weak portion 2421 has a second surface facing away from the electrode assembly 23. The maximum distance from the second surface to the outer surface of the raised portion 24221 can be measured as H2. When the pressure relief groove 245 is provided on both sides of the pressure relief mechanism 24 along the thickness direction of the wall portion 213, the maximum distance from the notch of the pressure relief groove 245 provided on the side of the pressure relief mechanism 24 facing away from the electrode assembly 23 to the outer surface of the raised portion 24221 can be measured as H2.

[0261] The raised height of the raised portion 24221 may be: H2 = 0.2 mm, 0.25, 0.3, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 4.9 mm, etc.

[0262] When H2 ≥ 0.2 mm, the height of the raised portion 24221 is higher, resulting in more significant deformation of the raised portion 24221. Under the same burst pressure, the thickness of the weak portion 2421 is greater, which helps reduce the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When H2 ≤ 4.9 mm, the raised portion 24221 is not too high. This, on the one hand, helps reduce the internal space occupied by the battery 100 or battery cell 20, thereby improving the energy density of the battery 100 or battery cell 20. On the other hand, it helps reduce the risk of interference between the raised portion 24221 and other components. Therefore, when 0.2 mm ≤ H2 ≤ 4.9 mm, both the lifespan and energy density of the battery cell 20 are maintained while reducing the risk of interference between the raised portion 24221 and other components.

[0263] Optionally, 0.3mm≤H2≤3mm.

[0264] The raised height of the raised portion 24221 may be: H2 = 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, etc.

[0265] When H2 ≥ 0.3mm, the height of the raised portion 24221 is higher, resulting in more pronounced deformation of the raised portion 24221. Under the same burst pressure, the thickness of the weak portion 2421 can be increased, reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. When H2 ≤ 3mm, the raised portion 24221 is not excessively high. This, on the one hand, helps reduce the internal space occupied by the battery 100 or battery cell 20, thereby improving the energy density of the battery 100 or battery cell 20. On the other hand, it helps reduce the risk of interference between the raised portion 24221 and other components. Therefore, when 0.3mm ≤ H2 ≤ 3mm, a better balance is achieved between the lifespan and energy density of the battery cell 20, while reducing the risk of interference between the raised portion 24221 and other components.

[0266] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 and Figure 10 , Figure 10 for Figure 9 Cross-sectional view at the mid-BB position. In some embodiments, the raised portion 24221 includes an arcuate portion 24221a extending along an arcuate trajectory. Along the arcuate trajectory, the arcuate portion 24221a includes a first end 24221b and a second end 24221c. The first end 24221b and the second end 24221c are arranged along a first direction. The first direction is parallel to the thickness direction of the wall of the outer surface of the housing 21 having the largest area.

[0267] The arc portion 24221a is an arc-shaped structure extending along an arc track. The arc track can be a circular arc track or a non-circular arc track.

[0268] Two ends of the arc portion 24221a along the extension direction of the arc track are respectively a first end 24221b and a second end 24221c, wherein the first end 24221b and the second end 24221c are arranged along the first direction.

[0269] Please refer to Figure 10 , the first direction is the Z1 direction shown in the figure.

[0270] The wall with the largest outer surface area of ​​the housing 21 is commonly called the large surface. Figure 4 , the thickness direction of the large surface is the Z2 direction shown in the figure.

[0271] The first direction is parallel to the thickness direction of the large surface. It should be noted that the first direction being parallel to the thickness direction of the large surface does not mean that the first direction and the thickness direction of the large surface are completely parallel, but rather that they can have a certain angle, for example, the angle between the first direction and the thickness direction of the large surface is less than or equal to 5°.

[0272] When the battery cell 20 expands, the wall with the largest outer surface area of ​​the outer shell 21 deforms the most. By configuring the raised portion 24221 to include an arcuate portion 24221a extending along an arcuate trajectory, with the first direction parallel to the thickness direction of the wall with the largest outer surface area of ​​the outer shell 21, the raised portion 24221 is more easily stretched by external forces when the battery cell 20 expands. This further reduces the pulling of the weak portion 2421 by external forces, lowering the risk of premature damage to the weak portion 2421 and thus improving the lifespan of the battery cell 20.

[0273] Please refer to Figure 11 , Figure 11 2 is a cross-sectional view of the pressure relief mechanism 24 provided in some further embodiments of the present application. In some further embodiments, the connecting portion 241 is a flat plate structure, and the weak portion 2421 directly connects the connecting portion 241 and the raised portion 24221 .

[0274] The connecting portion 241 is a flat plate structure, meaning that the connecting portion 241 has no local protrusions or depressions. In some embodiments, the connecting portion 241 is an annular structure. The connecting portion 241 is disposed around the outside of the weak portion 2421, and the weak portion 2421 is disposed around the outside of the pressure relief area 2422.

[0275] Please refer to Figure 11 ,exist Figure 11 The middle weak portion 2421 directly connects the connecting portion 241 and the raised portion 24221 . At this time, the pressure relief area 2422 as a whole rises in a direction away from the electrode assembly 23 to form the raised portion 24221 .

[0276] The connecting portion 241 is a flat plate structure, which makes it more convenient to connect the connecting portion 241 to the wall portion 213. The weak portion 2421 directly connects the connecting portion 241 and the raised portion 24221. When the battery cell 20 is depressurized, the raised portion 24221 can directly pull the weak portion 2421, so that the shear force on the weak portion 2421 is greater, thereby facilitating the opening of the weak portion 2421 to release pressure. Under the same blasting pressure, the thickness of the weak portion 2421 can be larger. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. In addition, the thicker the weak portion 2421, the easier it is to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0277] Please refer to Figure 12 , Figure 12 This is a cross-sectional view of the pressure relief mechanism 24 provided in some other embodiments of the present application. In some other embodiments, the connection portion 241 at least partially bulges away from the electrode assembly 23 , and the weak portion 2421 is connected to the portion of the connection portion 241 farthest from the electrode assembly 23 .

[0278] The connecting portion 241 may be partially raised in a direction away from the electrode assembly 23 , or the entire connecting portion 241 may be raised in a direction away from the electrode assembly 23 . The weak portion 2421 is connected to the portion of the connecting portion 241 farthest from the electrode assembly 23 .

[0279] By making the connecting portion 241 at least partially bulge in a direction away from the electrode assembly 23 and connecting the weak portion 2421 to the portion of the connecting portion 241 farthest from the electrode assembly 23, the weak portion 2421 is not easily affected when the connecting portion 241 is connected to the wall portion 213, which is beneficial to maintaining the performance of the weak portion 2421 and improving the life of the battery cell 20.

[0280] Please refer again Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the connecting portion 241 at least partially bulges in a direction facing the electrode assembly 23 , and the weak portion 2421 is connected to a portion of the connecting portion 241 closest to the electrode assembly 23 .

[0281] The connecting portion 241 may be partially raised in the direction facing the electrode assembly 23 , or the entire connecting portion 241 may be raised in the direction facing the electrode assembly 23 . The weak portion 2421 is connected to the portion of the connecting portion 241 closest to the electrode assembly 23 .

[0282] Please refer to Figure 6 ,exist Figure 6 In the illustrated embodiment, a portion of the connecting portion 241 is connected to the wall portion 213 , another portion of the connecting portion 241 bulges in the direction facing the electrode assembly 23 , and the weak portion 2421 is connected to the bulging portion of the connecting portion 241 facing the electrode assembly 23 .

[0283] The connecting portion 241 at least partially bulges in the direction facing the electrode assembly 23, and the bulging portion 24221 bulges in the direction away from the electrode assembly 23. The bulging direction of the connecting portion 241 is opposite to the bulging direction of the bulging portion 24221, so that the bulging portion 24221 can bulge using the bulging height of the connecting portion 241, which is beneficial to reducing the height of the bulging portion 24221 beyond the surface of the connecting portion 241 farthest from the electrode assembly 23, reducing the occupation of the internal space of the battery cell 20 or the battery 100, and helping to improve the energy density of the battery cell 20 or the battery 100. In addition, since the weak portion 2421 is connected to the part of the connecting portion 241 closest to the electrode assembly 23, that is, the position of the weak portion 2421 is closer to the electrode assembly 23 than the position of the fixed point of the connecting portion 241 and the wall portion 213, and since one end of the connecting portion 241 is constrained by the wall portion 213, under the action of air pressure, the part of the connecting portion 241 that bulges in the direction facing the electrode assembly 23 squeezes the weak portion 2421, thereby suppressing the cracking of the weak portion 2421 and preventing the weak portion 2421 from creeping and failing when the battery cell 20 is working normally, thereby effectively extending the life of the battery cell 20.

[0284] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the connection portion 241 is partially inclined toward the interior of the housing 21. In the cross section of the connection portion 241, the angle between the inclined portion of the connection portion 241 and the thickness direction of the wall portion 213 is a, satisfying: 30°≤a≤70°.

[0285] The portion of the connecting portion 241 is inclined toward the interior of the housing 21 , and the portion of the connecting portion 241 inclined toward the interior of the housing 21 is in a conical cylindrical shape.

[0286] a represents the angle between the inclined portion of the connecting portion 241 and the thickness direction of the wall portion 213 in the cross section of the connecting portion 241. Figure 6 The dashed line in FIG. 2 shows the straight line in the thickness direction of the wall portion 213. During measurement, the angle between the surface of the inclined portion of the connection portion 241 facing the electrode assembly 23 and the thickness direction of the wall portion 213 can be measured as a.

[0287] In the cross section of the connecting portion 241 , the angle between the inclined portion of the connecting portion 241 and the thickness direction of the wall portion 213 can be: a=30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, etc.

[0288] When a ≥ 30°, the inclination of the connecting portion 241 is greater, which better constrains the weak portion 2421 and helps reduce the risk of creep failure of the weak portion 2421. When a ≤ 70°, the inclination of the connecting portion 241 is not too great, which helps reduce stress concentration and the risk of brittle fracture.

[0289] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the raised height of the connecting portion 241 is H3, which satisfies: 0.2 mm ≤ H3 ≤ 7 mm.

[0290] H3 represents the height of the protrusion of the connection portion 241. The portion of the connection portion 241 connected to the wall portion 213 has a third surface facing the electrode assembly 23, and the inclined portion of the connection portion 241 has a fourth surface facing the electrode assembly 23. The maximum distance between the third surface and the fourth surface can be measured as H3.

[0291] The raised height of the connecting portion 241 may be: H3 = 0.2 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, etc.

[0292] When H3 ≥ 0.2 mm, the height of the protrusion of the connection portion 241 is greater, which helps reduce the height of the protrusion 24221 beyond the surface of the connection portion 241 farthest from the electrode assembly 23, reducing the space occupied by the battery cell 20 or battery 100, and helping to improve the energy density of the battery cell 20 or battery 100. When H3 ≤ 7 mm, the height of the protrusion of the connection portion 241 is not too large, which helps to reduce manufacturing difficulty and save manufacturing costs. Therefore, when 0.2 mm ≤ H3 ≤ 7 mm, the space occupied by the protrusion 24221 in the battery cell 20 or battery 100 can be effectively reduced, and the manufacturing cost of the battery cell 20 can be reduced.

[0293] Optionally, 0.2mm≤H3≤5mm.

[0294] The raised height of the connecting portion 241 may be: H3 = 0.2 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.

[0295] When H3 ≥ 0.2 mm, the height of the protrusion of the connection portion 241 is greater, which helps reduce the height of the protrusion 24221 beyond the surface of the connection portion 241 farthest from the electrode assembly 23, reducing the space occupied by the battery cell 20 or battery 100, and helping to improve the energy density of the battery cell 20 or battery 100. When H3 ≤ 5 mm, the height of the protrusion of the connection portion 241 is not too large, which is more conducive to reducing manufacturing difficulty and saving manufacturing costs. Therefore, when 0.2 mm ≤ H3 ≤ 5 mm, it can effectively reduce the space occupied by the protrusion 24221 in the battery cell 20 or battery 100, and reduce the manufacturing cost of the battery cell 20.

[0296] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, along the thickness direction of the wall portion 213, the connecting portion 241 has a first surface 2411 farthest from the electrode assembly 23, and the raised portion 24221 does not exceed the first surface 2411 in the direction away from the electrode assembly 23. The first surface 2411 is the surface of the connecting portion 241 farthest from the electrode assembly 23 along the thickness direction of the wall portion 213.

[0297] When the protrusion 24221 does not extend beyond the first surface 2411 in the direction away from the electrode assembly 23, the position of the protrusion 24221 farthest from the electrode assembly 23 can be flush with the first surface 2411, and the position of the protrusion 24221 farthest from the electrode assembly 23 can also be closer to the electrode assembly 23 than the first surface 2411.

[0298] By ensuring that the raised portion 24221 does not extend beyond the first surface 2411 in a direction away from the electrode assembly 23, on the one hand, the internal space occupied by the battery cell 20 or battery 100 can be reduced, which is beneficial for improving the energy density of the battery cell 20 or battery 100. On the other hand, the raised portion 24221 is less susceptible to external forces, which helps reduce the risk of premature damage to the weak portion 2421 and improves the life of the battery cell 20.

[0299] In other embodiments, along the thickness direction of the wall portion 213 , the protrusion 24221 does not extend beyond the outer surface of the wall portion 213 in a direction away from the electrode assembly 23 .

[0300] Along the thickness direction of the wall portion 213 , the wall portion 213 has an inner surface and an outer surface that are opposite to each other, wherein the inner surface faces the electrode assembly 23 and the outer surface faces away from the electrode assembly 23 .

[0301] When the protrusion 24221 does not extend beyond the outer surface of the wall 213 in the direction away from the electrode assembly 23, the position of the protrusion 24221 farthest from the electrode assembly 23 can be flush with the outer surface of the wall 213, and the position of the protrusion 24221 farthest from the electrode assembly 23 can also be closer to the electrode assembly 23 than the outer surface of the wall 213.

[0302] By ensuring that the raised portion 24221 does not extend beyond the outer surface of the wall portion 213 in a direction away from the electrode assembly 23, on the one hand, the internal space occupied by the battery 100 can be reduced, which is beneficial for improving the energy density of the battery 100. On the other hand, the raised portion 24221 is less likely to interfere with other components and is less susceptible to external forces, which helps reduce the risk of premature damage to the weak portion 2421 and improves the life of the battery cell 20.

[0303] In some further embodiments, along the thickness direction of the wall portion 213, the connection portion 241 has a first surface 2411 farthest from the electrode assembly 23. The battery cell 20 includes an electrode terminal 25, which is disposed on the wall portion 213 and at least partially protrudes from the outer surface of the wall portion 213. The electrode terminal 25 has a second surface 251 facing away from the electrode assembly 23. Along the thickness direction of the wall portion 213, the raised portion 24221 extends beyond the first surface 2411 in a direction from the second surface 251 to the first surface 2411, but does not extend beyond the second surface 251.

[0304] The electrode terminal 25 is used to electrically connect to the tab 232 of the electrode assembly 23 to input or output electrical energy from the battery cell 20. The electrode terminal 25 and the tab 232 can be directly connected, for example, by direct welding. The electrode terminal 25 and the tab 232 can also be indirectly connected, for example, by indirectly connecting the electrode terminal 25 and the tab 232 through a current collecting member. The electrode terminal 25 can be insulated and disposed on the wall portion 213, and at least partially protrude from the outer surface of the wall portion 213. The electrode terminal 25 has a second surface 251 that is farthest from the electrode assembly 23.

[0305] Along the thickness direction of the wall portion 213, the raised portion 24221 extends beyond the first surface 2411 in a direction away from the electrode assembly 23, but does not extend beyond the second surface 251. In other words, the position of the raised portion 24221 furthest from the electrode assembly 23 is further away from the electrode assembly 23 than the first surface 2411. The position of the raised portion 24221 furthest from the electrode assembly 23 may be flush with the second surface 251, or the position of the raised portion 24221 furthest from the electrode assembly 23 may be closer to the electrode assembly 23 than the second surface 251.

[0306] By ensuring that the raised portion 24221 extends beyond the first surface 2411 in a direction away from the electrode assembly 23, deformation of the raised portion 24221 is more pronounced. Under the same burst pressure, the thickness of the weak portion 2421 can be increased, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. By ensuring that the raised portion 24221 does not extend beyond the second surface 251 in a direction away from the electrode assembly 23, the risk of interference between the raised portion 24221 and other electrical connectors 241 is reduced.

[0307] In some further embodiments, the battery cell 20 includes an electrode terminal 25, which is disposed on the wall portion 213 and at least partially protrudes from the outer surface of the wall portion 213. The electrode terminal 25 has a second surface 251 facing away from the electrode assembly 23. Along the thickness direction of the wall portion 213, the protrusion 24221 does not extend beyond the second surface 251 in a direction facing away from the interior of the housing 21.

[0308] At this time, the raised portion 24221 may or may not exceed the first surface 2411 in a direction away from the interior of the housing 21 .

[0309] By ensuring that the raised portion 24221 does not extend beyond the second surface 251 in a direction away from the electrode assembly 23 , the risk of interference between the raised portion 24221 and other electrical connection portions 241 is reduced.

[0310] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the battery cell 20 includes an insulating member 27 disposed between the wall portion 213 and the electrode assembly 23 along the thickness direction of the wall portion 213 . Along the thickness direction of the wall portion 213 , the insulating member 27 is closer to the electrode assembly 23 than the pressure relief mechanism 24 .

[0311] The insulating member 27 has insulating properties and is disposed between the wall portion 213 and the electrode assembly 23 to insulate and isolate the wall portion 213 from the electrode assembly 23 to reduce the risk of short circuit. For example, the insulating member 27 may be made of plastic, rubber, or the like.

[0312] In some embodiments, the wall portion 213 is the end cap 212 . In this case, the insulating member 27 may be a lower plastic disposed between the end cap 212 and the electrode assembly 23 .

[0313] In other embodiments, the wall portion 213 is the bottom wall of the shell 211 . In this case, the insulating member 27 may be a spacer disposed between the bottom wall and the electrode assembly 23 .

[0314] The insulating member 27 is closer to the pressure relief mechanism 24 along the thickness direction of the wall portion 213 to reduce the risk of interference between the pressure relief mechanism 24 and the electrode assembly 23 .

[0315] By providing an insulating member 27 between the wall portion 213 and the electrode assembly 23, the wall portion 213 and the electrode assembly 23 can be insulated and isolated, reducing the risk of a short circuit caused by contact between the wall portion 213 and the electrode assembly 23. By placing the insulating member 27 closer to the electrode assembly 23 than the pressure relief mechanism 24, the risk of contact between the electrode assembly 23 and the pressure relief mechanism 24 can be reduced, and a fluid channel can be left between the electrode assembly 23 and the pressure relief mechanism 24, thereby facilitating pressure relief.

[0316] In some embodiments, the pressure relief mechanism 24 is made of 304 stainless steel, 305 stainless steel, or 316 stainless steel.

[0317] 304 stainless steel, 305 stainless steel and 316 stainless steel have the advantages of corrosion resistance, high temperature resistance and good processing performance. The pressure relief mechanism 24 made of 304 stainless steel, 305 stainless steel or 316 stainless steel has high strength, which can reduce the risk of deformation of the pressure relief mechanism 24 due to force, which is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to relieve pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell 20, and is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0318] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 7 In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245 , and a weak portion 2421 is formed at a position of the pressure relief mechanism 24 corresponding to the pressure relief groove 245 .

[0319] The pressure relief mechanism 24 has a fifth surface and a sixth surface disposed opposite each other in the thickness direction of the wall portion 213. The fifth surface faces the electrode assembly 23, while the sixth surface faces away from the electrode assembly 23. The pressure relief groove 245 can be provided on either the sixth surface or the fifth surface. For example, the pressure relief groove 245 is provided on the sixth surface, where the groove 245 is recessed from the sixth surface toward the fifth surface. The weak portion 2421 is the portion between the bottom surface of the groove 245 and the fifth surface.

[0320] The pressure relief groove 245 can be formed by various methods, such as stamping, cold heading, etc. Taking stamping as an example, the pressure relief groove 245 can be stamped on the pressure relief mechanism 24 along the thickness direction of the wall portion 213 to form the pressure relief groove 245 .

[0321] Stamping or cold-forging the pressure relief groove 245 causes the groove wall of the pressure relief groove 245 to undergo cold work hardening (changing the grain arrangement, causing lattice distortion, reducing the metal's plasticity, and increasing the material's hardness). This enhances its ability to resist external impact and makes it less susceptible to damage from external impact. This helps reduce the risk of leakage from the pressure relief mechanism 24.

[0322] By providing a pressure relief groove 245 on the pressure relief mechanism 24 , a weak portion 2421 is formed on the pressure relief mechanism 24 . When the battery cell 20 releases pressure, the pressure relief mechanism 24 is split along at least a portion of the weak portion 2421 . This is simple, convenient, and low-cost.

[0323] Please refer to Figure 8 、 Figure 9 、 Figure 10 and Figure 13 , Figure 13 for Figure 10 An enlarged view of position C. In some embodiments, the cross section of the pressure relief groove 245 is trapezoidal or conical.

[0324] When the cross section of the pressure relief groove 245 is trapezoidal or conical, it is beneficial for the pressure relief area 2422 to quickly open and relieve pressure when the battery cell 20 experiences thermal runaway.

[0325] Please refer to Figure 8 、 Figure 9 、 Figure 10 and Figure 13 In some embodiments, the pressure relief groove 245 includes two opposite groove side surfaces along the width direction of the pressure relief groove 245. The angle between the two groove side surfaces is b, which satisfies: 30°≤b≤90°.

[0326] Please refer to Figure 13 The width direction of the pressure relief groove 245 is the N direction shown in the figure.

[0327] b represents the angle between the two groove sides. The angle between the two groove sides can be: b = 30°, 35°, 40°, 45°, b = 50°, 55°, 60°, 65°, b = 70°, 75°, 80°, 85°, 90°, etc.

[0328] When b ≥ 30°, the pressure relief groove 245 can be easily punched out, reducing the difficulty of processing the pressure relief groove 245, thereby reducing the manufacturing cost of the battery cell 20. When b ≤ 90°, it can reduce material extrusion. Therefore, when 30° ≤ b ≤ 90°, it can reduce both the manufacturing cost of the battery cell 20 and the extrusion of material.

[0329] Optionally, 40°≤b≤80°.

[0330] The angle between the two groove sides can be: b=40°42°, 45°, 48°, b=50°, 52°, 55°, 58°, 60°, 62°, 65°, 68°, b=70°, 72°, 75°, 78°, 80°, etc.

[0331] When b ≥ 40°, the pressure relief groove 245 can be punched out more easily, reducing the difficulty of processing the pressure relief groove 245, thereby further reducing the manufacturing cost of the battery cell 20. When b ≤ 80°, it can further reduce material extrusion. Therefore, when 40° ≤ b ≤ 80°, it can reduce both the manufacturing cost of the battery cell 20 and the extrusion of material.

[0332] Please refer to Figure 8 、 Figure 9 、 Figure 10 and Figure 13 In some embodiments, the weak portion 2421 includes a first weak segment 24212 and a second weak segment 24213 , the first weak segment 24212 and the second weak segment 24213 are connected end to end, and the thickness of the first weak segment 24212 is less than the thickness of the second weak segment 24213 .

[0333] The first weak section 24212 serves as a pressure relief mechanism, and is used to enable the pressure relief mechanism 24 to rupture along at least a portion of the first weak section 24212 to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0334] The second weak section 24213 guides at least a portion of the pressure relief area 2422 to flip open. The second weak section 24213 has greater strength than the first weak section 24212. When the battery cell 20 releases pressure, the first weak section 24212 first ruptures, allowing the fluid inside the battery cell 20 to escape and release pressure. Subsequently, under the influence of the fluid, the pressure relief area 2422 rotates outward, pivoting around the second weak section 24213, to create a wider opening and achieve rapid pressure relief.

[0335] Please refer to Figure 9 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 arranged opposite each other. 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 collectively define a pressure relief zone 2422.

[0336] By providing the second weak section 24213, the strength of the pressure relief mechanism 24 at the position of the second weak section 24213 is weakened, making it easier for the pressure relief area 2422 to flip open under the action of the internal air pressure of the battery cell 20. This not only increases the probability of the pressure relief area 2422 opening, but also increases the opening speed of the pressure relief area 2422, thereby achieving rapid pressure relief and reducing the risk of explosion or fire of the battery cell 20, which is beneficial to improving the reliability of the battery cell 20.

[0337] Please refer to Figure 14 , Figure 14 Schematic diagrams of the structure of the pressure relief mechanism 24 provided in further embodiments of the present application. In further embodiments, along the extension direction of the second weak section 24213, the second weak section 24213 includes a third end 24213a and a fourth end 24213b. The line connecting the third end 24213a and the fourth end 24213b is a first line. The angle between the first line and the wall with the largest outer surface area of ​​the housing 21 in the thickness direction is C, satisfying the following: 0 ≤ C ≤ 45°.

[0338] The third end 24213a is one end of the second weak portion 2421 along its extension direction, and the fourth end 24213b is the other end of the second weak portion 24213 along its extension direction. The first connecting line is the connecting line between the third end 24213a and the fourth end 24213b.

[0339] The wall with the largest outer surface area of ​​the housing 21 is commonly referred to as the large surface. C represents the angle between the first connecting line and the thickness direction of the large surface.

[0340] The angle between the first connecting line and the wall with the largest outer surface area of ​​the shell 21 in the thickness direction can be: C=0, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, etc.

[0341] When 0≤C≤45°, the angle between the first connecting line and the wall with the largest outer surface area of ​​the shell 21 in the thickness direction is small. When the battery cell 20 is depressurized, even if the pressure relief area 2422 is not fully opened, the ejected high-temperature gas and / or flame is not likely to be directed toward another adjacent battery cell 20, and it is not likely to cause thermal runaway of another battery cell 20, which is beneficial to improving the reliability of the battery 100.

[0342] Optionally, the first connecting line is parallel to the thickness direction of the wall of the outer surface of the housing 21 with the largest area.

[0343] When the first connecting line is parallel to the thickness direction of the wall of the housing 21 having the largest outer surface area, C=0.

[0344] The first connecting line is parallel to the thickness direction of the wall with the largest outer surface area of ​​the shell 21. When the battery cell 20 is depressurized, even if the pressure relief area 2422 is not fully opened, the ejected high-temperature gas and / or flame is unlikely to be directed toward another adjacent battery cell 20, and is unlikely to cause thermal runaway of another battery cell 20, which is beneficial to improving the reliability of the battery 100.

[0345] Please refer to Figure 14 In some embodiments, the second weak section 24213 extends along an arc trajectory.

[0346] The second weak section 24213 may extend along a circular arc trajectory, or may extend along a non-circular arc trajectory.

[0347] When the second weak section 24213 extends along the arc trajectory, the area of ​​the pressure relief zone 2422 is larger, making it easier to open a larger opening for pressure relief.

[0348] In other embodiments, the second weakened section 24213 extends along a straight line.

[0349] When the second weak section 24213 extends along a straight line, the second weak section 24213 is a strip-shaped structure.

[0350] When the second weak section 24213 extends along a straight line, it is easy to process and has a better effect of guiding the pressure relief area 2422 to flip.

[0351] Please refer again Figure 8 、 Figure 9 and Figure 10 In some embodiments, the minimum thickness of the second weak section 24213 is H4, satisfying: 0.05 mm ≤ H4 ≤ 0.2 mm.

[0352] H4 represents the minimum thickness of the second weak section 24213 along the thickness direction of the wall portion 213. During measurement, the thickness at different positions may be measured multiple times and the average value may be taken as H4.

[0353] The minimum thickness of the second weak section 24213 along the thickness direction of the wall portion 213 can be: H4 = 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, etc.

[0354] When H4 ≥ 0.05mm, the thickness of the second weak section 24213 is relatively large, which can reduce the risk of the second weak section 24213 cracking due to changes in air pressure inside the battery cell 20 or external impact, thereby improving the reliability of the battery cell 20. When H4 ≤ 0.2mm, the thickness of the second weak section 24213 is not too large, which helps reduce the resistance to the flipping of the pressure relief area 2422, facilitates the rapid flipping and opening of the pressure relief area 2422, and improves the timeliness of the pressure relief of the battery cell 20. Therefore, when 0.05mm ≤ H4 ≤ 0.2mm, the thickness of the second weak section 24213 is moderate, making the second weak section 24213 less likely to crack due to changes in air pressure inside the battery cell 20 or external impact, while also facilitating the rapid flipping and opening of the pressure relief area 2422, thereby improving the timeliness of the pressure relief of the battery cell 20.

[0355] Optionally, 0.05mm≤H4≤0.15mm.

[0356] The minimum thickness of the second weak section 24213 along the thickness direction of the wall portion 213 can be: H4 = 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, etc.

[0357] When H4 ≥ 0.05mm, the thickness of the second weak section 24213 is relatively large, which can reduce the risk of the second weak section 24213 cracking due to changes in air pressure inside the battery cell 20 or external impact, thereby improving the reliability of the battery cell 20. When H4 ≤ 0.15mm, the thickness of the second weak section 24213 is not too large, which is more conducive to reducing the resistance to the flipping of the pressure relief area 2422, facilitating the rapid flipping and opening of the pressure relief area 2422, and further improving the timely pressure relief of the battery cell 20. Therefore, when 0.05mm ≤ H4 ≤ 0.2mm, the thickness of the second weak section 24213 is moderate, making the second weak section 24213 less likely to crack due to changes in air pressure inside the battery cell 20 or external impact, while also facilitating the rapid flipping and opening of the pressure relief area 2422, thereby improving the timely pressure relief of the battery cell 20.

[0358] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the thickness of the pressure relief mechanism 24 is H5, which satisfies: 0.05 mm ≤ H5 ≤ 0.5 mm.

[0359] H5 represents the thickness of the pressure relief mechanism 24. It should be noted that the thickness of the pressure relief mechanism 24 refers to the thickness of the pressure relief mechanism 24 at non-weak locations. For example, in an embodiment where the pressure relief mechanism 24 is provided with a pressure relief groove 245, the thickness of the pressure relief mechanism 24 refers to the thickness of the area excluding the pressure relief groove 245. Multiple measurements can be taken and the average value calculated as H5.

[0360] The thickness of the pressure relief mechanism 24 can be: H5 = 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0361] When H5 ≥ 0.05 mm, the thickness of the pressure relief mechanism 24 is greater, providing greater structural strength. This reduces the risk of deformation of the pressure relief mechanism 24 due to stress, thereby improving the service life and reliability of the battery cell 20. When H5 ≤ 0.5 mm, the thickness of the pressure relief mechanism 24 is not excessive, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.05 mm ≤ H5 ≤ 0.5 mm, the service life, reliability, and manufacturing cost of the battery cell 20 are balanced.

[0362] Optionally, 0.05mm≤H5≤0.3mm.

[0363] The thickness of the pressure relief mechanism 24 can be: H5 = 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, etc.

[0364] When H5 ≥ 0.05mm, the thickness of the pressure relief mechanism 24 is greater, providing greater structural strength. This reduces the risk of deformation of the pressure relief mechanism 24 due to stress, thereby improving the service life and reliability of the battery cell 20. When H5 ≤ 0.3mm, the thickness of the pressure relief mechanism 24 is not excessive, further helping to control the manufacturing cost of the battery cell 20. Therefore, when 0.05mm ≤ H5 ≤ 0.3mm, the service life, reliability, and manufacturing cost of the battery cell 20 are better balanced.

[0365] Please refer again Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the pressure relief mechanism 24 is located at one end of the pressure relief hole 2131 facing the electrode assembly 23 .

[0366] Along the thickness direction of the wall portion 213 , the pressure relief hole 2131 has two opposite ends, one end facing the electrode assembly 23 and the other end away from the electrode assembly 23 . The pressure relief mechanism 24 is disposed at the end of the pressure relief hole 2131 facing the electrode assembly 23 .

[0367] Optionally, the battery cell 20 includes a protective member 26 , which is disposed at an end of the pressure relief hole 2131 away from the electrode assembly 23 and covers the pressure relief hole 2131 .

[0368] When the pressure relief mechanism 24 is arranged at the end of the pressure relief hole 2131 facing the shell 211, the risk of the pressure relief mechanism 24 being affected by external force is smaller, which is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to relieve pressure prematurely and is beneficial to improving the service life and reliability of the battery cell 20.

[0369] In some embodiments, the base material of the wall portion 213 is iron, and the pressure relief mechanism 24 is connected to the wall portion 213 by welding.

[0370] "The base material of wall portion 213 is iron" means that iron is the largest material by mass in wall portion 213. For example, wall portion 213 can be made of carbon steel or stainless steel. Carbon steel can be low carbon steel, medium carbon steel, or high carbon steel. For example, wall portion 213 can be made of 304 stainless steel, 305 stainless steel, 316 stainless steel, etc.

[0371] The base material of the pressure relief mechanism 24 and the wall portion 213 is both iron. This effectively enhances the structural strength of the wall portion 213 and the pressure relief mechanism 24, reduces the risk of deformation due to stress, and helps reduce the risk of premature valve opening and pressure relief by the pressure relief mechanism 24, thereby improving the service life and reliability of the battery cell 20. Furthermore, welding the pressure relief mechanism 24 to the wall portion 213 is easier, which helps reduce the risk of weld cracks between the pressure relief mechanism 24 and the end cap 212, thereby reducing the risk of leakage from the battery cell 20 and improving the reliability of the battery cell 20.

[0372] Please refer to Figure 3 、 Figure 4 、 Figure 5 and Figure 6 In some embodiments, the housing 21 includes a shell 211 and an end cap 212 . The shell 211 has an opening, and the end cap 212 is connected to the shell 211 and closes the opening. The end cap 212 is a wall 213 , or the shell 211 includes the wall 213 .

[0373] The shell 211 includes an integrally formed side wall and bottom wall, that is, the shell 211 is manufactured using an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding. In other words, the side wall and bottom wall of the shell 211 are an integral structure.

[0374] The housing 211 includes a wall portion 213, that is, the wall portion 213 is a wall of the housing 211. Exemplarily, the wall portion 213 is a bottom wall of the housing 211 disposed opposite the end cap 212 in the thickness direction of the wall portion 213. Of course, in other embodiments, the wall portion 213 may also be a side wall of the housing 211.

[0375] It should be noted that the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 can also have other structures. For example, the outer shell 21 may include a shell 211 and an end cover 212. The interior of the shell 211 forms a accommodating cavity with an opening, and the accommodating cavity is used to accommodate the electrode assembly 23. The end cover 212 closes the opening, and the end cover 212 is a wall portion 213.

[0376] It should be noted that the structure of the battery cell 20 can be various. In some embodiments, the outer shell 21 may include a shell 211 and two end covers 212. A accommodating cavity is formed inside the shell 211, and the accommodating cavity is used to accommodate the electrode assembly 23. The shell 211 has openings at both ends in the thickness direction of the wall portion 213, and both openings are connected to the accommodating cavity. The two end covers 212 respectively close the two openings, and one of the two end covers 212 is the wall portion 213.

[0377] The shell 211 of the outer shell 21 is provided with openings at both ends in the thickness direction of the wall portion 213, and the two end covers 212 respectively close the two openings. The wall portion 213 is one of the two end covers 212. The battery cell 20 adopting this structure is convenient for assembling the battery cell 20 from both ends of the shell 211, which is beneficial to reducing the manufacturing difficulty and assembly difficulty of the battery cell 20.

[0378] When the end cap 212 is a wall portion 213, the pressure relief mechanism 24 is disposed on the end cap 212, which simplifies and facilitates manufacturing. When the housing 211 includes a wall portion 213, the pressure relief mechanism 24 is disposed on a wall of the housing 211. The fluid medium ejected by the pressure relief mechanism 24 is less likely to act on other electrical connection structures on the end cap 212, thereby reducing the risk of short circuits in the battery cells 20.

[0379] Please refer to Figure 8 、 Figure 9 、 Figure 10 and Figure 11The embodiment of the present application also provides a pressure relief mechanism 24. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421, a raised portion 24221 and a connecting portion 241. The weak portion 2421 is configured to be at least partially destroyed when the battery cell 20 releases pressure. The weak portion 2421 is annular, the raised portion 24221 is located in the area surrounded by the weak portion 2421, and the connecting portion 241 is located on the outside of the weak portion 2421. The raised portion 24221 is a raised structure raised along the thickness direction of the pressure relief mechanism 24. The minimum thickness of the weak portion 2421 is H1, satisfying 0.01mm≤H1≤0.2mm.

[0380] Please refer to Figure 10 The thickness direction of the pressure relief mechanism 24 is the Y direction shown in the figure.

[0381] The pressure relief mechanism 24 is a component for opening when the internal pressure or temperature of the battery cell 20 reaches a bursting pressure to relieve the internal pressure of the battery cell 20 .

[0382] "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.

[0383] The weak portion 2421 serves as a pressure relief mechanism, allowing the pressure relief mechanism 24 to rupture along the weak portion 2421 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, thereby releasing the pressure within the battery cell 20. In some embodiments, the strength of the pressure relief mechanism 24 at the weak portion 2421 may be lower than the strength of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of the internal pressure to release the pressure within the battery cell 20. In other embodiments, the melting point of the pressure relief mechanism 24 at the weak portion 2421 may be lower than the melting point of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of high temperature to release the pressure within the battery cell 20.

[0384] The weak portion 2421 is an annular structure, and the weak portion 2421 can be in the shape of a circular ring or an elliptical ring. The weak portion 2421 divides the pressure relief mechanism 24 into two parts, one part is located on the inner side of the weak portion 2421, and the other part is located on the outer side of the weak portion 2421. The raised portion 24221 is located on the inner side of the weak portion 2421, and the raised portion 24221 is a raised structure raised along the thickness direction of the pressure relief mechanism 24. The raised structure is a structure in which both the inner and outer surfaces are arched along the thickness direction of the pressure relief mechanism 24. The connecting portion 241 is located on the outer side of the weak portion 2421. The connecting portion 241 is the portion of the pressure relief mechanism 24 used to connect to the wall portion 213. For example, the connecting portion 241 can be welded to the wall portion 213.

[0385] H1 represents the minimum thickness of the weak portion 2421 along the thickness direction of the pressure relief mechanism 24. During measurement, the thickness at different locations can be measured multiple times and the average value can be taken as H1. The minimum thickness of the weak portion 2421 along the thickness direction of the pressure relief mechanism 24 can be: H1 = 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.

[0386] When releasing pressure, the existing pressure relief mechanism 24 will gradually arch from a flat plate structure in a direction away from the electrode assembly 23 under the action of the internal pressure of the battery cell 20. After arching, it will open and release pressure under the action of the internal pressure of the battery cell 20. In the embodiment of the present application, the raised portion 24221 of the pressure relief mechanism 24 rises in a direction away from the electrode assembly 23. The raised portion 24221 forms a pre-deformation on the inner side of the weak portion 2421, thereby facilitating the rupture of the weak portion 2421 to release pressure. In this way, under the same blasting pressure, the thickness of the weak portion 2421 can be larger. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to rupture prematurely due to pressure changes inside the battery cell 20 or external impacts, which helps to reduce the risk of premature damage to the weak portion 2421 and helps to increase the life of the battery cell 20. When H1≥0.01mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easy to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of the weak portion 2421 being damaged prematurely, and is beneficial to improving the life of the battery cell 20. When H1≤0.2mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 thermally runs away, which is beneficial to improving the timeliness of the pressure relief mechanism 24. Therefore, when 0.01mm≤H1≤0.2mm, the service life and timeliness of pressure relief of the battery cell 20 can be taken into account. In addition, the base material of the pressure relief mechanism 24 is iron, which can effectively improve the structural strength of the pressure relief mechanism 24, reduce the risk of deformation of the pressure relief mechanism 24 due to stress, and is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to release pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell 20. Compared with the aluminum explosion-proof valve in the prior art, the thickness of the weak portion 2421 of the pressure relief mechanism 24 provided in the embodiment of the present application is smaller. During manufacturing, a slight change in the thickness of the weak portion 2421 will cause a large change in the bursting pressure of the battery cell 20. By providing the raised portion 24221, the thickness of the weak portion 2421 can be increased under the same bursting pressure. The larger the thickness of the weak portion 2421, the easier it is to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0387] Please refer to Figure 8 、 Figure 9 、 Figure 10 and Figure 11 In some embodiments, the area enclosed by the weak portion 2421 is the pressure relief area 2422. Along the thickness direction of the pressure relief mechanism 24, the projected area of ​​the pressure relief area 2422 is S. 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or,

[0388] 350mm 2≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or,

[0389] 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or,

[0390] 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or,

[0391] 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

[0392] The pressure relief area 2422 is the area of ​​the pressure relief mechanism 24 enclosed by the weak portion 2421 , that is, the area of ​​the pressure relief mechanism 24 located inside the weak portion 2421 .

[0393] The pressure relief area 2422 includes the above-mentioned raised portion 24221. For example, the pressure relief area 2422 may be partially raised in a direction away from the electrode assembly 23 to form the raised portion 24221, or the pressure relief area 2422 may be raised as a whole in a direction away from the electrode assembly 23 to form the raised portion 24221. Figure 6 ,exist Figure 6 In the illustrated embodiment, the pressure relief area 2422 as a whole bulges in a direction away from the electrode assembly 23 to form a bulge 24221 . In this case, the pressure relief area 2422 is the bulge 24221 .

[0394] S represents the projected area of ​​the pressure relief zone 2422 along the thickness direction of the wall portion 213. Figure 9 , Figure 9 The S is marked with a mesh line. It should be noted that the mesh line here is only for the convenience of displaying S and does not represent any entity meaning.

[0395] The projected area of ​​the pressure relief zone 2422 along the thickness direction of the wall portion 213 can be: S = 100 mm 2 , 150mm 2 , 200mm 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.

[0396] When 100mm 2 ≤S≤450mm 2 When 0.010mm≤H1≤0.160mm. When 100mm 2 ≤S≤450mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.010mm, 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, etc.

[0397] When the projected area of ​​the pressure relief zone 2422 is larger, the pressure relief zone 2422 is more susceptible to the internal pressure and the weak portion 2421 is more likely to rupture. Therefore, when the projected area of ​​the pressure relief zone 2422 is increased, in order to ensure the same bursting pressure, the thickness of the weak portion 2421 can be increased. 2 <S≤450mm 2 , and H1 ≥ 0.010mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.010mm≤H1≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0398] When 350mm 2 ≤S≤850mm 2 When 0.015mm≤H1≤0.170mm. When 350mm 2 ≤S≤850mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.015mm, 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, etc.

[0399] When 350mm 2 ≤S≤850mm 2 , and H1 ≥ 0.015mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2, and when H1≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.015mm≤H1≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0400] When 750mm 2 ≤S≤1250mm 2 When 0.020mm≤H1≤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: H1 = 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.

[0401] When 750mm 2 ≤S≤1250mm 2 , and H1 ≥ 0.020mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.020mm≤H1≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0402] When 1150mm 2 ≤S≤1650mm 2 When 0.025mm≤H1≤0.190mm. When 1150mm 2 ≤S≤1650mm 2, the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 0.025mm, 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.

[0403] When 1150mm 2 ≤S≤1650mm 2 , and H1 ≥ 0.025mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.025mm≤H1≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0404] When 1550mm 2 ≤S≤2100mm 2 When 0.030mm≤H1≤0.200mm. When 1550mm 2 ≤S≤2100mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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.

[0405] When 1550mm 2 ≤S≤2100mm 2, and H1 ≥ 0.030mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.030mm≤H1≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0406] In some embodiments, 100 mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or,

[0407] 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H1≤0.170mm; or,

[0408] 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or,

[0409] 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or,

[0410] 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

[0411] When 100mm 2 ≤S≤450mm 2 When 0.020mm≤H1≤0.160mm. When 100mm 2 ≤S≤450mm 2, the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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.

[0412] When 100mm 2 <S≤450mm 2 , and H1 ≥ 0.020mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H1≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.020mm≤H1≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0413] When 350mm 2 ≤S≤850mm 2 When 0.025mm≤H1≤0.170mm. When 350mm 2 ≤S≤850mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1=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.

[0414] When 350mm 2 ≤S≤850mm 2 , and H1 ≥ 0.025mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2 , and when H1≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.025mm≤H1≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0415] When 750mm 2 ≤S≤1250mm 2 When 0.030mm≤H1≤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: H1 = 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.

[0416] When 750mm 2 ≤S≤1250mm 2 , and H1 ≥ 0.030mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H1≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.030mm≤H1≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0417] When 1150mm 2 ≤S≤1650mm 2 When 0.035mm≤H1≤0.190mm. When 1150mm 2 ≤S≤1650mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1=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.

[0418] When 1150mm 2 ≤S≤1650mm 2 , and H1 ≥ 0.035mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H1≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.035mm≤H1≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0419] When 1550mm 2 ≤S≤2100mm 2 When 0.040mm≤H1≤0.200mm. When 1550mm 2 ≤S≤2100mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H1 = 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, 0.12 5mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 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, 0.195mm, 0.200mm, etc.

[0420] When 1550mm 2 ≤S≤2100mm 2 , and H1 ≥ 0.040mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H1≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.040mm≤H1≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0421] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 The raised height of the raised portion 24221 is H2, which satisfies: 0.2mm≤H2≤4.9mm.

[0422] H2 represents the height of the raised portion 24221. The height of the raised portion 24221 can be: H2 = 0.2mm, 0.25, 0.3, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 4.9mm, etc.

[0423] When H2 ≥ 0.2 mm, the height of the raised portion 24221 is higher, resulting in more significant deformation of the raised portion 24221. Under the same burst pressure, the thickness of the weak portion 2421 is greater, which helps reduce the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When H2 ≤ 4.9 mm, the raised portion 24221 is not too high. This, on the one hand, helps reduce the internal space occupied by the battery 100 or battery cell 20, thereby improving the energy density of the battery 100 or battery cell 20. On the other hand, it helps reduce the risk of interference between the raised portion 24221 and other components. Therefore, when 0.2 mm ≤ H2 ≤ 4.9 mm, both the lifespan and energy density of the battery cell 20 are maintained while reducing the risk of interference between the raised portion 24221 and other components.

[0424] Optionally, 0.3mm≤H2≤3mm.

[0425] The raised height of the raised portion 24221 may be: H2 = 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, etc.

[0426] When H2 ≥ 0.3mm, the height of the raised portion 24221 is higher, resulting in more pronounced deformation of the raised portion 24221. Under the same burst pressure, the thickness of the weak portion 2421 can be increased, reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. When H2 ≤ 3mm, the raised portion 24221 is not excessively high. This, on the one hand, helps reduce the internal space occupied by the battery 100 or battery cell 20, thereby improving the energy density of the battery 100 or battery cell 20. On the other hand, it helps reduce the risk of interference between the raised portion 24221 and other components. Therefore, when 0.3mm ≤ H2 ≤ 3mm, a better balance is achieved between the lifespan and energy density of the battery cell 20, while reducing the risk of interference between the raised portion 24221 and other components.

[0427] The embodiment of the present application further provides a battery 100 , which includes the above-mentioned battery cell 20 .

[0428] In some embodiments, the battery 100 includes a plurality of battery cells 20 arranged along a second direction. The weak portion 2421 includes a first weak section 24212 and a second weak section 24213. The first weak section 24212 and the second weak section 24213 are connected end to end, and the thickness of the first weak section 24212 is less than that of the second weak section 24213. Along the extension direction of the second weak section 24213, the second weak section 24213 includes a third end 24213a and a fourth end 24213b. The line connecting the third end 24213a and the fourth end 24213b is a first line. The angle between the first line and the second direction is D, satisfying the following: 0 ≤ D ≤ 45°.

[0429] The battery 100 may include two battery cells 20, three battery cells 20, four battery cells 20, or more battery cells 20. The plurality of battery cells 20 are arranged along the second direction.

[0430] The first weak section 24212 serves to relieve pressure, and is used to enable the pressure relief mechanism 24 to rupture 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, so as to release the pressure inside the battery cell 20. The second weak section 24213 serves to guide at least a portion of the pressure relief zone 2422 to flip open. The second weak section 24213 has higher strength than the first weak section 24212. When the battery cell 20 is depressurized, the first weak section 24212 ruptures first to allow the fluid medium in the battery cell 20 to flow out and relieve pressure. Afterwards, under the action of the fluid medium, the pressure relief zone 2422 can flip outward with the second weak section 24213 as the rotation axis to open a larger opening and achieve rapid pressure relief.

[0431] The third end 24213a is one end of the second weak portion 2421 along its extension direction, and the fourth end 24213b is the other end of the second weak portion 24213 along its extension direction. The first connecting line is the connecting line between the third end 24213a and the fourth end 24213b.

[0432] D represents the angle between the first connecting line and the second direction. The angle between the first connecting line and the second direction can be: D=0, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, etc.

[0433] When 0≤D≤45°, the angle between the first connecting line and the second direction is small. When the battery cell 20 is depressurized, even if the pressure relief area 2422 is not fully opened, the ejected high-temperature gas and / or flame is not likely to be directed toward another adjacent battery cell 20, and is not likely to cause thermal runaway of another battery cell 20, which is beneficial to improving the reliability of the battery 100.

[0434] Optionally, the first connecting line is parallel to the second direction.

[0435] When the first line is parallel to the second direction, D=0.

[0436] The first connecting line is parallel to the second direction. When the battery cell 20 is depressurized, even if the pressure relief area 2422 is not fully opened, the ejected high-temperature gas and / or flame is unlikely to be directed toward another adjacent battery cell 20, and is unlikely to cause thermal runaway of another battery cell 20, which is beneficial to improving the reliability of the battery 100.

[0437] In some embodiments, the second direction is the thickness direction of the wall of the housing 21 having the largest outer surface area.

[0438] Arranging the plurality of battery cells 20 along the thickness direction of the wall of the outer surface of the housing 21 having the largest area can help fully utilize the space and improve the energy density of the battery 100 .

[0439] An embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0440] According to some embodiments of this application, please refer to Figures 3 to 6 .

[0441] The embodiment of the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 23, and a pressure relief mechanism 24. The housing 21 has a wall portion 213, which is provided with a pressure relief hole 2131. The electrode assembly 23 is accommodated in the housing 21, and the pressure relief mechanism 24 covers the pressure relief hole 2131. The pressure relief mechanism 24 is made of iron and includes a weak portion 2421, a raised portion 24221, 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. The weak portion 2421 is annular, the raised portion 24221 is located within the area enclosed by the weak portion 2421, and the connecting portion 241 is located outside the weak portion 2421 and connected to the wall portion 213. The raised portion 24221 is a raised structure that rises away from the electrode assembly 23. The minimum thickness of the weak portion 2421 is H1, satisfying the condition 0.01mm≤H1≤0.2mm. Conventional pressure relief mechanisms 24 gradually arch from a flat plate structure away from the electrode assembly 23 under the action of internal pressure in the battery cell 20 during pressure relief. After arching, they then open to release pressure under the action of internal pressure in the battery cell 20. In contrast, in the present embodiment, the raised portion 24221 of the pressure relief mechanism 24 rises away from the electrode assembly 23. The raised portion 24221 creates a pre-deformation inside the weak portion 2421, facilitating the rupture of the weak portion 2421 to release pressure. This allows for a greater thickness of the weak portion 2421 under the same burst pressure. During normal use of the battery cell 20, the weak portion 2421 is less likely to rupture prematurely due to pressure changes within the battery cell 20 or external impacts. This reduces the risk of premature damage to the weak portion 2421 and improves the life of the battery cell 20. When H1≥0.01mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easy to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of the weak portion 2421 being damaged prematurely, and is beneficial to improving the life of the battery cell 20. When H1≤0.2mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 thermally runs away, which is beneficial to improving the timeliness of the pressure relief mechanism 24. Therefore, when 0.01mm≤H1≤0.2mm, the service life and timeliness of pressure relief of the battery cell 20 can be taken into account. In addition, the base material of the pressure relief mechanism 24 is iron, which can effectively improve the structural strength of the pressure relief mechanism 24, reduce the risk of deformation of the pressure relief mechanism 24 due to stress, and is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to release pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell 20.Compared with the aluminum explosion-proof valve in the prior art, the thickness of the weak portion 2421 of the pressure relief mechanism 24 provided in the embodiment of the present application is smaller. During manufacturing, a slight change in the thickness of the weak portion 2421 will cause a large change in the bursting pressure of the battery cell 20. By providing the raised portion 24221, the thickness of the weak portion 2421 can be increased under the same bursting pressure. The larger the thickness of the weak portion 2421, the easier it is to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0442] The area enclosed by the weak portion 2421 is a pressure relief area 2422 . The projected area of ​​the pressure relief area 2422 along the thickness direction of the wall portion 213 is S.

[0443] Among them, 100mm 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or,

[0444] 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or,

[0445] 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or,

[0446] 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or,

[0447] 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

[0448] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: The housing has a wall portion, wherein the wall portion is provided with a pressure relief hole; an electrode assembly housed in the housing; A pressure relief mechanism covers the pressure relief hole, the base material of the pressure relief mechanism is iron, the pressure relief mechanism includes a weak portion, a raised portion and a connecting portion, the weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the shell reaches a threshold value, the weak portion is annular, the raised portion is located in the area surrounded by the weak portion, the connecting portion is located on the outside of the weak portion and connected to the wall portion, the raised portion is a raised structure raised in a direction away from the electrode assembly, the minimum thickness of the weak portion is H1, and satisfies 0.01mm≤H1≤0.2mm.

2. The battery cell according to claim 1, characterized in that: The boundary of the raised portion is at least partially adjacent to the boundary of the weakened portion.

3. The battery cell according to claim 2, characterized in that: The boundary of the raised portion is completely adjacent to the boundary of the weakened portion.

4. The battery cell according to claim 1, wherein: The area enclosed by the weak portion is a pressure relief zone, and the projected area of ​​the pressure relief zone along the thickness direction of the wall is S; Among them, 100mm 2 ≤450mm 2 , and 0.010mm≤H1≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

5. The battery cell according to claim 4, characterized in that: 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H1≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

6. The battery cell according to claim 1, characterized in that: The raised portion has a raised height H2, which satisfies the following conditions: 0.2 mm ≤ H2 ≤ 4.9 mm.

7. The battery cell according to claim 6, characterized in that: 0.3mm≤H2≤3mm.

8. The battery cell according to claim 1, characterized in that: The raised portion includes an arc-shaped portion extending along an arc-shaped trajectory. Along the extension direction of the arc-shaped trajectory, the arc-shaped portion includes a first end and a second end. The first end and the second end are arranged along a first direction, and the first direction is parallel to the thickness direction of the wall with the largest outer surface area of ​​the shell.

9. The battery cell according to claim 1, characterized in that: The connecting portion is a flat plate structure, and the weak portion directly connects the connecting portion and the raised portion.

10. The battery cell according to claim 1, characterized in that: At least a portion of the connecting portion bulges in a direction away from the electrode assembly, and the weak portion is connected to a portion of the connecting portion that is farthest from the electrode assembly.

11. The battery cell according to claim 1, characterized in that: At least a portion of the connecting portion bulges in a direction facing the electrode assembly, and the weak portion is connected to a portion of the connecting portion closest to the electrode assembly.

12. The battery cell according to claim 11, characterized in that: A portion of the connecting portion is inclined toward the interior of the housing; In a cross section of the connecting portion, an angle a formed between the inclined portion of the connecting portion and the thickness direction of the wall portion satisfies the following relationship: 30°≤a≤70°.

13. The battery cell according to claim 11, characterized in that: The raised height of the connecting portion is H3, which satisfies: 0.2 mm ≤ H3 ≤ 7 mm, and optionally, 0.2 mm ≤ H3 ≤ 5 mm.

14. The battery cell according to claim 11, characterized in that: Along the thickness direction of the wall portion, the connecting portion has a first surface farthest from the electrode assembly, and the raised portion does not extend beyond the first surface along a direction away from the electrode assembly.

15. The battery cell according to any one of claims 1 to 13, characterized in that: Along the thickness direction of the wall portion, the raised portion does not extend beyond the outer surface of the wall portion in a direction away from the electrode assembly.

16. The battery cell according to any one of claims 1 to 13, characterized in that: The connecting portion has a first surface that is farthest from the electrode assembly along the thickness direction of the wall portion, and the battery cell includes an electrode terminal, which is disposed on the wall portion and at least partially protrudes from an outer surface of the wall portion, and has a second surface that is away from the electrode assembly; Along the thickness direction of the wall portion, the raised portion extends beyond the first surface in a direction away from the electrode assembly and does not extend beyond the second surface.

17. The battery cell according to any one of claims 1 to 13, characterized in that: The battery cell includes an electrode terminal, the electrode terminal is disposed on the wall portion and at least partially protrudes from an outer surface of the wall portion, and the electrode terminal has a second surface facing away from the electrode assembly; Along the thickness direction of the wall portion, the raised portion does not extend beyond the second surface in a direction away from the electrode assembly.

18. The battery cell according to any one of claims 1 to 13, characterized in that: The battery cell includes an insulating member disposed between the wall portion and the electrode assembly along a thickness direction of the wall portion; Along the thickness direction of the wall portion, the insulating member is closer to the electrode assembly than the pressure relief mechanism.

19. The battery cell according to any one of claims 1 to 13, characterized in that: The pressure relief mechanism is made of 304 stainless steel, 305 stainless steel or 316 stainless steel.

20. The battery cell according to any one of claims 1 to 13, characterized in that: The pressure relief mechanism is provided with a pressure relief groove, and the position of the pressure relief mechanism corresponding to the pressure relief groove forms the weak portion.

21. The battery cell according to claim 20, characterized in that: The cross section of the pressure relief groove is trapezoidal or conical.

22. The battery cell according to claim 20, characterized in that: Along the width direction of the pressure relief groove, the pressure relief groove includes two groove side surfaces arranged opposite to each other, and the angle between the two groove side surfaces is b, which satisfies: 30°≤b≤90°, optionally, 40°≤b≤80°.

23. The battery cell according to any one of claims 1 to 13, characterized in that: The weak portion includes a first weak section and a second weak section, the first weak section and the second weak section are connected end to end, and the thickness of the first weak section is smaller than the thickness of the second weak section.

24. The battery cell according to claim 23, characterized in that: Along the extension direction of the second weak section, the second weak section includes a third end and a fourth end, the line connecting the third end and the fourth end is a first line, and the angle between the first line and the thickness direction of the wall with the largest outer surface area of ​​the shell is C, satisfying: 0≤C≤45°.

25. The battery cell according to claim 24, characterized in that: The first connecting line is parallel to the thickness direction of the wall of the housing having the largest outer surface area.

26. The battery cell according to claim 24, characterized in that: The second weak section extends along an arc trajectory.

27. The battery cell according to claim 24, characterized in that: The second weakened section extends along a straight line trajectory.

28. The battery cell according to claim 23, characterized in that: The minimum thickness of the second weak section is H4, which satisfies: 0.05 mm ≤ H4 ≤ 0.2 mm, and optionally, 0.05 mm ≤ H4 ≤ 0.15 mm.

29. The battery cell according to any one of claims 1 to 13, characterized in that: The thickness of the pressure relief mechanism is H5, which satisfies: 0.05mm≤H5≤0.5mm, optionally, 0.05mm≤H5≤0.3mm.

30. The battery cell according to any one of claims 1 to 13, characterized in that: The base material of the wall portion is iron, and the pressure relief mechanism is connected to the wall portion by welding.

31. A pressure relief mechanism for a battery cell, characterized in that: The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion, a raised portion and a connecting portion. The weak portion is configured to be at least partially destroyed when the battery cell releases pressure. The weak portion is annular, the raised portion is located within the area enclosed by the weak portion, and the connecting portion is located outside the weak portion. The raised portion is a raised structure that rises along the thickness direction of the pressure relief mechanism. The minimum thickness of the weak portion is H1, satisfying 0.01mm≤H1≤0.2mm.

32. The pressure relief mechanism according to claim 31, characterized in that: The area enclosed by the weak portion is the pressure relief area, and the projected area of ​​the pressure relief area along the thickness direction of the pressure relief mechanism is S; Among them, 100mm 2 ≤S≤450mm 2 , and 0.010mm≤H1≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H1≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H1≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H1≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H1≤0.200mm.

33. The pressure relief mechanism according to claim 32, characterized in that: 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H1≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H1≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H1≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H1≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H1≤0.200mm.

34. The pressure relief mechanism according to any one of claims 31 to 33, characterized in that: The raised portion has a raised height H2, which satisfies the following conditions: 0.2 mm ≤ H2 ≤ 4.9 mm.

35. The pressure relief mechanism according to claim 34, characterized in that: 0.3mm≤H2≤3mm.

36. A battery, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 30.

37. The battery according to claim 36, characterized in that The battery comprises a plurality of battery cells, and the plurality of battery cells are arranged along the second direction; The weak portion includes a first weak section and a second weak section, the first weak section and the second weak section are connected end to end, and the thickness of the first weak section is smaller than the thickness of the second weak section; Along the extension direction of the second weak section, the second weak section includes a third end and a fourth end, a line connecting the third end and the fourth end is a first line, and an angle D between the first line and the second direction satisfies: 0≤D≤45°.

38. The battery according to claim 37, characterized in that The first connecting line is parallel to the second direction.

39. The battery according to claim 37 or 38, characterized in that The second direction is the thickness direction of the wall of the housing having the largest outer surface area.

40. An electrical device, characterized in that: The battery cell comprises a battery cell according to any one of claims 1 to 30, and the battery cell is used to provide electrical energy to the electrical device.

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