battery

Abstract

This utility model relates to a battery, including a casing with a pressure relief valve. The pressure relief valve includes a first pressure relief groove and a second pressure relief groove on the side wall of the casing. Both the first and second pressure relief grooves extend along a first direction. The second pressure relief groove is located on at least one side of the first pressure relief groove along the first direction. A first weak area is provided within the first pressure relief groove, and the first weak area extends along the first direction. The wall thickness of the side wall of the casing with the pressure relief valve is greater than the wall thickness of the area of ​​the casing corresponding to the first weak area. A second weak area is provided within the second pressure relief groove, and the second weak area extends along the first direction. The wall thickness of the area of ​​the casing corresponding to the first weak area is less than the wall thickness of the area of ​​the casing corresponding to the second weak area. The projections of the first and second weak areas in a second direction at least partially overlap. In this utility model, the pressure relief valve of the battery can be opened quickly and smoothly, thereby improving safety during use.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery. Background Technology

[0002] Currently, with the rapid development of new energy vehicles, their market share is also continuously increasing. As one of the most crucial components of new energy vehicles, batteries also face high safety requirements.

[0003] To ensure battery safety and prevent explosions or fires under extreme conditions, a pressure relief valve is installed on the battery to release gas when the internal pressure rises rapidly.

[0004] Existing pressure relief valves include scoring, which involves creating a slit along the length of the battery to form a pressure relief valve. However, under extreme battery conditions, these pressure relief valves are unable to quickly release the heat and gas inside the battery. Utility Model Content

[0005] The purpose of this invention is to provide a battery that improves safety during use.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0007] A battery having a first direction and a second direction that intersect perpendicularly, includes a housing, on which a pressure relief valve is provided. The pressure relief valve includes a first pressure relief groove and a second pressure relief groove disposed on a side wall of the housing. Both the first pressure relief groove and the second pressure relief groove extend along the first direction. The second pressure relief groove is disposed on at least one side of the first pressure relief groove along the first direction. A first weak area is provided in the first pressure relief groove, and the first weak area extends along the first direction. The wall thickness of the side wall of the housing where the pressure relief valve is disposed is greater than the wall thickness of the area of ​​the housing corresponding to the first weak area. A second weak area is provided in the second pressure relief groove, and the second weak area extends along the first direction. The wall thickness of the area of ​​the housing corresponding to the first weak area is less than the wall thickness of the area of ​​the housing corresponding to the second weak area. The projection of the first weak area in the second direction and the projection of the second weak area in the second direction at least partially overlap.

[0008] Compared with the prior art, the battery of this utility model embodiment has the following advantages:

[0009] In this invention, the outer casing is provided with a first pressure relief groove and a second pressure relief groove. The second pressure relief groove is provided on at least one side of the first pressure relief groove along the first direction. A first weak area is provided within the first pressure relief groove, and a second weak area is provided within the second pressure relief groove. The projection of the first weak area in the second direction at least partially overlaps with the projection of the second weak area in the second direction. By utilizing the second weak area in conjunction with the first weak area, an easily tearable pressure relief area can be formed between the first and second weak areas. This assists in tearing the first weak area outwards, allowing the area between the first and second pressure relief grooves to open quickly, thereby allowing pressure relief within the battery... When thermal runaway causes an increase in internal pressure, the area between the first and second pressure relief grooves can be easily opened to form a larger pressure relief port, thereby quickly releasing the internal pressure of the battery. At the same time, since the wall thickness of the area of ​​the outer casing corresponding to the first weak area is smaller than the wall thickness of the area of ​​the outer casing corresponding to the second weak area, the structural strength of the area of ​​the outer casing located at the first weak area is reduced. Therefore, when the internal pressure of the battery increases, the first weak area can be quickly torn apart first to form a pressure relief port, and then the pressure relief port can quickly extend to the second weak area, so as to open the pressure relief valve in time and quickly release the internal heat of the battery, improving the safety of battery use. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the battery structure of this utility model;

[0011] Figure 2 This is a schematic diagram of the pressure relief valve of the battery according to this utility model;

[0012] Figure 3 This is a schematic diagram of one of the pressure relief valves of this utility model;

[0013] Figure 4 This is a schematic diagram of another pressure relief valve of this utility model;

[0014] Figure 5 This is a schematic diagram of other pressure relief valves of this utility model.

[0015] In the diagram, 1 is the outer shell; 11 is the outer casing; and 12 is the cover plate.

[0016] 2. Pressure relief valve; 21. First pressure relief groove; 22. Second pressure relief groove; 23. Third pressure relief groove; 24. Fourth pressure relief groove; 25. First weak area; 26. Second weak area; 27. Third weak area. Detailed Implementation

[0017] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0018] In the description of this utility model, it should be understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, parts, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts, components, and / or groups thereof. It should be understood that when we say a part is "connected" to another part, it can be directly connected to the other part, or there may be intermediate parts. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0019] like Figures 1 to 3 As shown, this utility model relates to a battery having a first direction and a second direction that intersect perpendicularly, including a housing 1. A pressure relief valve 2 is provided on the housing 1. The pressure relief valve 2 is used to release heat and gas inside the housing 1 when the battery experiences thermal runaway. The pressure relief valve 2 includes a first pressure relief groove 21 and a second pressure relief groove 22 disposed on the side wall of the housing 1. Both the first pressure relief groove 21 and the second pressure relief groove 22 extend along the first direction. The second pressure relief groove 22 is provided on at least one side of the first pressure relief groove 21 along the first direction. A first thin... The first weak area 25 extends along the first direction. The wall thickness of the side wall of the housing 1 with the pressure relief valve 2 is greater than the wall thickness of the area of ​​the housing 1 corresponding to the first weak area 25. The second pressure relief groove 22 has a second weak area 26, which extends along the first direction. The wall thickness of the area of ​​the housing 1 corresponding to the first weak area 25 is less than the wall thickness of the area of ​​the housing 1 corresponding to the second weak area 26. The projection of the first weak area 25 in the second direction and the projection of the second weak area 26 in the second direction at least partially overlap.

[0020] In this invention, the outer casing 1 is provided with a first pressure relief groove 21 and a second pressure relief groove 22. The second pressure relief groove 22 is provided on at least one side of the first pressure relief groove 21 along the first direction. A first weak area 25 is provided within the first pressure relief groove 21, and a second weak area 26 is provided within the second pressure relief groove 22. The projection of the first weak area 25 in the second direction at least partially overlaps with the projection of the second weak area 26 in the second direction. Therefore, by using the second weak area 26 in conjunction with the first weak area 25, an easily tearable pressure relief area can be formed between the first weak area 25 and the second weak area 26. This assists in tearing the first weak area 25 outwards, allowing the area between the first pressure relief groove 21 and the second pressure relief groove 22 to open quickly. Therefore, when thermal runaway occurs within the battery, causing an increase in internal pressure, the area between the first pressure relief groove 21 and the second pressure relief groove 22 can be easily opened to form a larger pressure relief port, thereby quickly releasing the internal pressure of the battery. At the same time, since the wall thickness of the area of ​​the outer shell 1 corresponding to the first weak area 25 is less than the wall thickness of the area of ​​the outer shell 1 corresponding to the second weak area 26, the structural strength of the area of ​​the outer shell 1 located at the first weak area 25 is reduced. Thus, when the internal pressure of the battery increases, the first weak area 25 can be quickly torn apart first to form a pressure relief port, and then the pressure relief port can quickly extend to the second weak area 26, so that the pressure relief valve 2 can be opened in time to quickly release the internal heat of the battery and improve the safety of battery use.

[0021] It should be noted that the first weak area 25 is located on the outer shell 1. That is, the first weak area 25 is the area with the smallest wall thickness of the outer shell 1. The structural strength of this area is the weakest. So when the battery experiences thermal runaway and the internal pressure increases, the weakest area will crack rapidly in order to quickly release the heat inside the battery.

[0022] In some embodiments, the area where the first weak region 25 and the second weak region 26 overlap in the second direction has a dimension A in the first direction, and the dimension of the first weak region 25 in the first direction has a dimension B1 in the first direction, wherein 0.5 ≤ A / B1 ≤ 1. The value of A / B1 can also be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95.

[0023] By maintaining 0.5≤A / B1≤1, the second weak area 26 can provide better assistance to the first weak area 25 in quickly tearing apart, allowing the outer casing 1 to quickly tear to the second weak area 26 after the first weak area 25 cracks to form a pressure relief port, so as to quickly release the internal heat of the battery.

[0024] In some embodiments, the projection of the first weak region 25 in the second direction lies within the projection of the second weak region 26 in the second direction. That is, the size of the first weak region 25 in the first direction is smaller than the size of the second weak region 26 in the first direction, so that when the battery experiences thermal runaway, it is easier to crack from the first weak region 25 to quickly release heat.

[0025] In some embodiments, the dimension of the first weak region 25 in the first direction is B1 (mm), and the dimension of the second weak region 26 in the first direction is B2 (mm), wherein 0.5 ≤ B1 / B2 ≤ 2. The value of B1 / B2 can also be 0.55, 0.6, 0.65, 0.7, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 1.85, 1.9, or 1.95.

[0026] By controlling 0.5≤B1 / B2≤2, the second weak area 26 is better utilized to assist the first weak area 25 in quickly tearing and extending to the second weak area 26, so as to quickly release the heat inside the battery, improve the safety of the battery use, and also avoid causing the overall strength of the casing 1 to deteriorate.

[0027] In some embodiments, the dimension of the second weak area 26 in the first direction is B2 (mm), and the dimension of the side wall of the housing 1 with the pressure relief valve 2 in the first direction is C (mm), wherein 0.1 ≤ B2 / C ≤ 0.6. The value of B2 / C can also be 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or 0.55.

[0028] That is, by keeping 0.1≤B2 / C≤0.6, the size of the second weak area 26 on the side wall of the outer casing 1 will not be too large, thereby avoiding poor structural strength of the outer casing 1. Then, the size of the second weak area 26 on the side wall of the outer casing 1 will not be too small, so that when the battery experiences thermal runaway, the pressure relief valve 2 can open quickly to release the heat inside the battery quickly and ensure safety in use.

[0029] In some embodiments, in the second direction, the minimum distance between the first weak area 25 and the second weak area 26 is D, in mm, wherein 5 mm ≤ D ≤ 15 mm. The value of D can also be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm or 14 mm.

[0030] By maintaining a diameter of 5mm ≤ D ≤ 15mm, the pressure relief valve 2 can be quickly opened to release the heat inside the battery and ensure safety. On the other hand, it can prevent the first pressure relief groove 21 and the second pressure relief groove 22 from being too close together. Therefore, when processing the second pressure relief groove 22 after processing the first pressure relief groove 21, it is less likely to cause damage to the first pressure relief groove 21 due to stress, thus avoiding abnormal opening of the pressure relief valve 2 during normal charging and discharging of the battery.

[0031] In some embodiments, the width of the second pressure relief groove 22 in the second direction is E, in mm, where 1 mm ≤ E ≤ 5 mm. The value of E can also be 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or 4.5 mm.

[0032] By controlling 1mm≤E≤5mm, the auxiliary pressure relief port can be quickly and smoothly torn open after the first pressure relief groove 21 cracks, so as to quickly release the internal heat of the battery. At the same time, it can also reduce the impact on the structural strength of the outer shell 1.

[0033] In some embodiments, multiple second pressure relief grooves 22 are spaced apart along the second direction. This allows the pressure relief port to be quickly torn open along the multiple second pressure relief grooves 22 after the first pressure relief groove 21 is broken, thereby quickly releasing the internal heat of the battery and improving safety during use.

[0034] Preferably, the minimum distance between two adjacent second pressure relief grooves 22 is F, in mm, where 1 mm ≤ F ≤ 5 mm. The value of F can also be 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or 4.5 mm.

[0035] That is, by keeping 1mm≤F≤5mm, after the first pressure relief groove 21 cracks, the pressure relief port can be quickly torn open along the multiple second pressure relief grooves 22, quickly releasing the internal heat of the battery and improving the safety of use.

[0036] In some embodiments, in the second direction, the two ends of the plurality of second weak areas 26 on the plurality of second pressure relief grooves 22 are aligned, thereby facilitating the rapid opening of the pressure relief valve 2 and the rapid release of the internal heat of the battery.

[0037] In some embodiments, in two adjacent second weak regions 26 of the second pressure relief grooves 22, the ratio of the size of one second weak region 26 in the first direction to the size of the other second weak region 26 in the first direction is 0.5-1.5. This allows the pressure relief valve 2 to open smoothly and quickly, rapidly releasing the heat inside the battery.

[0038] In some embodiments, the first pressure relief groove 21 is provided with second pressure relief grooves 22 on both sides along the first direction. This increases the area of ​​the pressure relief port after the pressure relief valve 2 is opened, so as to quickly release the heat inside the battery.

[0039] In some embodiments, the pressure relief valve 2 further includes a third pressure relief groove 23 disposed on the side wall of the housing 1. The first pressure relief groove 21 is provided with the third pressure relief groove 23 at both ends in the first direction. The third pressure relief groove 23 is provided with a third weak area 27, and the first weak area 25 and the third weak area 27 are intersected.

[0040] That is, by providing the third pressure relief groove 23 at both ends of the first pressure relief groove 21, and by having the first weak area 25 intersect with the third weak area 27, the third pressure relief groove 23 and the third weak area 27 can assist the pressure relief valve 2 to open quickly after the first pressure relief groove 21 is torn open.

[0041] Preferably, the third pressure relief groove 23 and the third weak area 27 are both extended along the second direction, and the extension direction of the first weak area 25 is perpendicular to the extension direction of the third weak area 27.

[0042] By allowing both the third pressure relief groove 23 and the third weak area 27 to extend along the second direction, the outer casing 1, after cracking from the first pressure relief groove 21, can quickly tear along the third pressure relief groove 23 and the third weak area 27 to the second pressure relief groove 22, so that the pressure relief valve 2 can quickly open to a sufficient size, thereby quickly releasing the internal heat of the battery and improving the safety of the battery.

[0043] Furthermore, the second pressure relief groove 22 is located in the area between the first pressure relief groove 21 and the third pressure relief groove 23, so that after the outer shell 1 is cracked from the first pressure relief groove 21, it can be quickly torn along the third pressure relief groove 23 and the third weak area 27 to the second pressure relief groove 22, thereby realizing the rapid opening of the pressure relief valve 2.

[0044] Furthermore, the minimum distance between the second weak area 26 and the third weak area 27 in the first direction is G, in mm, where 2mm ≤ G ≤ 10mm. This allows the pressure relief valve 2 to open quickly and smoothly. The value of G can also be 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or 9mm.

[0045] Combination Figure 4 and Figure 5As shown, in some embodiments, the pressure relief valve 2 further includes a fourth pressure relief groove 24 disposed on the side wall of the housing 1. The fourth pressure relief groove 24 extends along the second direction, communicates with the first pressure relief groove 21, and is located between the two third pressure relief grooves 23 at both ends of the first pressure relief groove 21.

[0046] That is, by setting the fourth pressure relief groove 24, it can also play a guiding role after the first pressure relief groove 21 cracks, so that the pressure relief valve 2 can be opened quickly.

[0047] Preferably, a second pressure relief groove 22 is provided between the third pressure relief groove 23 and the fourth pressure relief groove 24, and each second pressure relief groove 22 along the first direction is independently provided. This enables the pressure relief valve 2 to be opened quickly and ensures the structural strength of the outer casing 1.

[0048] In some embodiments, the length direction of the first pressure relief groove 21 is parallel to the length direction of the outer casing 1.

[0049] That is, the extension direction of the first pressure relief groove 21 is the same as the length direction of the battery. Therefore, the structural strength of the outer shell 1 can be minimized while ensuring that the first pressure relief groove 21 has sufficient size.

[0050] In some embodiments, the first pressure relief groove 21 includes an inner groove, the bottom of which is provided with grooves along the first direction to form the first weak area 25.

[0051] Specifically, the inner groove can be provided on the inner side wall of the outer shell 1 or on the outer side wall of the outer shell 1. That is, the inner groove can be facing the inside of the outer shell 1 or facing the outside of the outer shell 1.

[0052] In some embodiments, the outer casing 1 is made of aluminum, and the minimum distance between the first weak area 25 and the second weak area 26 is H, in mm, where 7 mm ≤ H ≤ 15 mm. This ensures the structural strength of the outer casing 1 and guarantees that the pressure relief valve 2 can open smoothly and quickly in the event of battery thermal runaway. The value of H can also be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, or 14 mm.

[0053] Specifically, the outer shell 1 is made of aluminum alloy, which may be aluminum-magnesium alloy, aluminum-manganese alloy, etc.

[0054] In some embodiments, the outer casing 1 is made of steel, and the minimum distance between the first weak area 25 and the second weak area 26 is J, in mm, where 5 mm ≤ J ≤ 14 mm. This ensures the structural strength of the outer casing 1 and guarantees that the pressure relief valve 2 can open smoothly and quickly in the event of battery thermal runaway. The value of J can also be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, or 13 mm.

[0055] Specifically, the material of the outer shell 1 can be steel, stainless steel, nickel-plated steel, carbon steel, etc.

[0056] In some embodiments, the outer casing 1 may also be made of titanium.

[0057] In some embodiments, the wall thickness of the area corresponding to the first weak area 25 of the outer casing 1 is K, in mm, where 0.05 mm ≤ K ≤ 0.25 mm. This ensures that the pressure relief valve 2 can open smoothly and quickly release the heat of the battery in the event of thermal runaway. The value of K can also be 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, or 0.24 mm.

[0058] The wall thickness of the area corresponding to the second weak area 26 of the outer shell 1 is L, in mm, where 0.08 mm ≤ L ≤ 0.28 mm. This ensures that the pressure relief valve 2 can open smoothly and quickly release the heat of the battery in the event of thermal runaway. The value of L can also be 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, or 0.26 mm.

[0059] The wall thickness of the area corresponding to the outer casing 1 and the third weak area 27 is M, in mm, where 0.08 mm ≤ M ≤ 0.28 mm. This ensures that the pressure relief valve 2 can open smoothly and quickly release the heat of the battery in the event of thermal runaway. The value of M can also be 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, or 0.26 mm.

[0060] In some embodiments, the wall thickness of the region corresponding to the third weak area 27 of the outer shell 1 is greater than the wall thickness of the region corresponding to the first weak area 25 of the outer shell 1.

[0061] Thus, when the battery experiences thermal runaway, the first weak area 25 and the first pressure relief groove 21 can crack first, then crack along the third weak area 27, and gradually tear to the second pressure relief groove 22, thereby opening the pressure relief valve 2.

[0062] In some embodiments, the outer casing 1 includes a housing 11 and a cover plate 12. The housing 11 has an opening, and the cover plate 12 covers the opening of the housing 11. The pressure relief valve 2 is located on one side of the housing 11, and the thickness of the side of the housing 11 with the pressure relief valve 2 is 0.5mm-1.5mm. The minimum distance between the first weak area 25 and the second weak area 26 in the second direction is 7mm-15mm. This allows the pressure relief valve 2 to open smoothly. The thickness of the side of the housing 11 with the pressure relief valve 2 can also be 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, or 1.4mm. The minimum distance between the first weak area 25 and the second weak area 26 in the second direction can also be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, or 14mm.

[0063] In some embodiments, the outer casing 1 includes a housing 11 and a cover plate 12. The housing 11 has an opening, and the cover plate 12 covers the opening of the housing 11. The pressure relief valve 2 is located on the cover plate 12. The cover plate 12 has a thickness of 1mm-2.5mm, and the minimum distance between the first weak area 25 and the second weak area 26 in the second direction is 5mm-12mm. This allows the pressure relief valve 2 to open smoothly. The thickness of the cover plate 12 can also be 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, or 2.4mm. The minimum distance between the first weak area 25 and the second weak area 26 in the second direction can also be 6mm, 7mm, 8mm, 9mm, 10mm, or 11mm.

[0064] It should be noted that the battery also includes a cell, which is located inside the outer casing 1. Thermal runaway of the battery is equivalent to thermal runaway of the cell. The cell includes a positive electrode, a negative electrode, and a separator, which are stacked together, with the separator located between the positive and negative electrode.

[0065] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material. The positive electrode current collector can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metal and insulating materials. The positive electrode active material includes a positive electrode active material, a conductive agent, and a binder. The positive electrode active material includes one or more of lithium-containing positive electrode active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0066] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material. The negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil material formed by combining metal and insulating materials. The negative electrode active material includes a negative electrode active material, a conductive agent, a binder, etc. The negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0067] It should be noted that the first direction can be the length direction of the battery, and the second direction can be the width direction of the battery; or, the first direction can be the width direction of the battery, and the second direction can be the length direction of the battery.

[0068] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery having a first direction and a second direction that intersect perpendicularly, characterized in that, The device includes a housing, on which a pressure relief valve is provided. The pressure relief valve includes a first pressure relief groove and a second pressure relief groove disposed on the side wall of the housing. Both the first pressure relief groove and the second pressure relief groove extend along a first direction. The second pressure relief groove is disposed on at least one side of the first pressure relief groove along the first direction. A first weak area is disposed within the first pressure relief groove, and the first weak area extends along the first direction. The wall thickness of the side wall of the housing where the pressure relief valve is disposed is greater than the wall thickness of the area of ​​the housing corresponding to the first weak area. A second weak area is disposed within the second pressure relief groove, and the second weak area extends along the first direction. The wall thickness of the area of ​​the housing corresponding to the first weak area is less than the wall thickness of the area of ​​the housing corresponding to the second weak area. The projection of the first weak area in the second direction and the projection of the second weak area in the second direction at least partially overlap.

2. The battery according to claim 1, characterized in that, The area where the first weak area and the second weak area overlap in the second direction has a dimension A in the first direction, and the dimension of the first weak area in the first direction is B1 in the first direction, where 0.5 ≤ A / B1 ≤ 1.

3. The battery according to claim 1, characterized in that, The projection of the first weak area in the second direction lies within the projection of the second weak area in the second direction.

4. The battery according to claim 1, characterized in that, The first weak area has a dimension of B1 in the first direction, and the second weak area has a dimension of B2 in the first direction, where 0.5 ≤ B1 / B2 ≤ 2.

5. The battery according to claim 1, characterized in that, The second weak area has a dimension of B2 in the first direction, and the side wall of the housing with the pressure relief valve has a dimension of C in the first direction, where 0.1 ≤ B2 / C ≤ 0.

6.

6. The battery according to claim 1, characterized in that, In the second direction, the minimum distance between the first weak area and the second weak area is D, in mm, where 5 mm ≤ D ≤ 15 mm.

7. The battery according to claim 1, characterized in that, The width of the second pressure relief groove in the second direction is E, in mm, where 1 mm ≤ E ≤ 5 mm.

8. The battery according to claim 1, characterized in that, The second pressure relief groove is provided in multiple spaces along the second direction.

9. The battery according to claim 8, characterized in that, The minimum distance between two adjacent second pressure relief grooves is F, in mm, where 1 mm ≤ F ≤ 5 mm.

10. The battery according to claim 8, characterized in that, In the second direction, the two ends of the multiple second weak areas on the multiple second pressure relief grooves are aligned.

11. The battery according to claim 8, characterized in that, In the two adjacent second pressure relief grooves, the ratio of the size of one second weak area in the first direction to the size of the other second weak area in the first direction is 0.5-1.

5.

12. The battery according to claim 1, characterized in that, The first pressure relief groove is provided with the second pressure relief groove on both sides along the first direction.

13. The battery according to claim 1, characterized in that, The pressure relief valve further includes a third pressure relief groove provided on the side wall of the housing. The first pressure relief groove has the third pressure relief groove at both ends in the first direction. The third pressure relief groove has a third weak area, and the first weak area and the third weak area are intersected.

14. The battery according to claim 13, characterized in that, Both the third pressure relief groove and the third weak area extend along the second direction, and the extension direction of the first weak area is perpendicular to the extension direction of the third weak area.

15. The battery according to claim 14, characterized in that, The second pressure relief groove is located in the area between the first pressure relief groove and the third pressure relief groove.

16. The battery according to claim 15, characterized in that, The minimum distance between the second weak area and the third weak area is G, in mm, where 2mm≤G≤10mm.

17. The battery according to claim 13, characterized in that, The pressure relief valve further includes a fourth pressure relief groove disposed on the side wall of the housing. The fourth pressure relief groove is connected to the first pressure relief groove, and the fourth pressure relief groove is located between the two third pressure relief grooves at both ends of the first pressure relief groove.

18. The battery according to claim 17, characterized in that, The second pressure relief groove is provided between the third pressure relief groove and the fourth pressure relief groove, and each of the second pressure relief grooves along the first direction is independently provided.

19. The battery according to claim 1, characterized in that, The length direction of the first pressure relief groove is parallel to the length direction of the outer shell.

20. The battery according to claim 1, characterized in that, The first pressure relief groove includes an inner groove, and the inner groove is provided with grooves along the first direction to form the first weak area.

21. The battery according to claim 1, characterized in that, The outer shell is made of aluminum, and the minimum distance between the first weak area and the second weak area is H, in mm, where 7mm≤H≤15mm.

22. The battery according to claim 1, characterized in that, The outer shell is made of steel. The minimum distance between the first weak area and the second weak area is J, in mm, where 5 mm ≤ J ≤ 14 mm.

23. The battery according to claim 13, characterized in that, The wall thickness of the outer shell corresponding to the first weak area is K, in mm, where 0.05 mm ≤ K ≤ 0.25 mm; The wall thickness of the area corresponding to the second weak zone of the outer shell is L, in mm, where 0.08 mm ≤ L ≤ 0.28 mm; The wall thickness of the area corresponding to the third weak zone of the outer shell is M, in mm, where 0.08 mm ≤ M ≤ 0.28 mm.

24. The battery according to claim 13, characterized in that, The wall thickness of the region corresponding to the third weak area of ​​the outer shell is greater than the wall thickness of the region corresponding to the first weak area of ​​the outer shell.

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