Battery cell and battery pack

Abstract

The present application relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises a casing and an explosion-proof valve; the casing is provided with an accommodating cavity; the casing comprises a plurality of sidewalls that are used for defining the accommodating cavity; the sidewalls are provided with a pressure relief hole communicated with the accommodating cavity; the explosion-proof valve covers and seals the pressure relief hole; the explosion-proof valve comprises a body and a base; the body is provided with a notch; the body comprises an elastic strain portion; the elastic strain portion is arranged around at least part of the notch; the base surrounds the body, and the base is separately connected to the body and the sidewalls; the elastic strain portion is used for generating elastic deformation in the direction from the base to the notch. According to the present application, the explosion-proof valve comprising the elastic strain portion is arranged in the pressure relief hole on the casing, so as to prevent welding deformation from being generated when welding the explosion-proof valve to the casing, thereby preventing the opening pressure change of the explosion-proof valve, and further improving the safety of the battery cell.

Description

Single cells and battery packs

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number CN202410101129.5, entitled “Single Cell and Battery Pack,” filed with the Patent Office of China on January 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application belongs to the field of battery technology, and specifically relates to a single cell and a battery pack. Background Art

[0004] The explosion-proof valve on the single cell is a safety device that is designed to actively rupture when the single cell is over-pressurized to relieve the pressure inside the single cell, thereby preventing the single cell from exploding.

[0005] In current technology, the explosion-proof valve and the shell are connected by welding. Heat is inevitably generated during the welding process, and the explosion-proof valve will produce welding deformation, resulting in local stress concentration, which affects the opening pressure of the explosion-proof valve and thus reduces the safety performance of the entire single battery.

[0006] Application Contents

[0007] In view of this, the present application provides a single battery, aiming to overcome the current technical problem of welding deformation generated during welding through an explosion-proof valve.

[0008] In a first aspect, the present application provides a single cell battery, comprising:

[0009] A housing, wherein the housing has a receiving cavity and includes a plurality of side walls, wherein the plurality of side walls are used to enclose the receiving cavity; and the side walls have a pressure relief hole communicating with the receiving cavity;

[0010] an explosion-proof valve, the explosion-proof valve cover sealing the pressure relief hole, the explosion-proof valve comprising a body and a base, the body having a notch, the body comprising an elastic strain portion, the elastic strain portion being disposed around at least a portion of the notch, the base surrounding the body, and the base being connected to the body and the sidewall, respectively;

[0011] Wherein, the elastic strain portion is used to generate elastic deformation along the direction from the base to the notch;

[0012] The elastic strain portion has a minimum dimension δ along the thickness direction of the explosion-proof valve, and the elastic strain portion has a minimum dimension W along a direction perpendicular to the thickness direction of the explosion-proof valve, satisfying: 1.5δ≤W≤5δ;

[0013] The elastic strain portion extends in a curved shape along a direction from the notch to the base;

[0014] The elastic strain portion extends in an arc shape along a direction from the notch to the base, and the radius of the arc shape is R, which satisfies: 0.5mm≤R≤15mm.

[0015] Beneficial effect: The present application provides an explosion-proof valve with an elastic strain portion in the pressure relief hole on the shell, thereby avoiding welding deformation when the explosion-proof valve is welded to the shell, thereby avoiding changes in the opening pressure of the explosion-proof valve, and further improving the safety performance of the single battery.

[0016] In an optional embodiment, the elastic strain portion extends in a broken line shape along a direction from the notch to the base.

[0017] In an optional embodiment, the body further includes a main body portion, the notch is provided on the main body portion, the main body portion is connected to the elastic strain portion, the main body portion has a dimension H along the thickness direction of the explosion-proof valve, and the elastic strain portion has a minimum dimension δ along the thickness direction of the explosion-proof valve, satisfying: δ≤H.

[0018] In an optional embodiment, the main body includes a plurality of elastic strain portions arranged at intervals, and among two adjacent elastic strain portions, one elastic strain portion is arranged around the other elastic strain portion.

[0019] In an optional embodiment, the elastic strain portion is arranged to surround the notch.

[0020] In an optional embodiment, the shell further includes a first wall and a second wall arranged opposite to each other, the multiple side walls are arranged between the first wall and the second wall, the first wall, the second wall and the multiple side walls are connected to form the accommodating cavity, and the area of ​​the side wall is smaller than the area of ​​the first wall and the second wall.

[0021] In an optional embodiment, the single battery further includes a cover assembly, wherein the cover assembly is connected to the shell and covers the accommodating cavity.

[0022] In a second aspect, the present application further provides a battery pack, comprising the single battery as described above, wherein the battery pack has a first direction, a second direction, and a third direction, wherein the first direction, the second direction, and the third direction intersect;

[0023] The battery pack has a first size L1 in the first direction, which satisfies: 100 mm ≤ L1 ≤ 600 mm, or 600 mm ≤ L1 ≤ 1500 mm;

[0024] The battery pack has a second size L2 in the second direction, satisfying: 50 mm ≤ L2 ≤ 250 mm;

[0025] The battery pack has a third dimension L3 in the third direction, satisfying: 10 mm ≤ L3 ≤ 600 mm.

[0026] Beneficial effect: The battery pack includes the above-mentioned single battery, and the safety performance of the battery pack is improved by using the single battery having an explosion-proof valve with an elastic strain portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] FIG1 is a top view of a single cell provided in an embodiment of the present application;

[0029] FIG2 is a schematic structural diagram of an explosion-proof valve in a single cell provided in an embodiment of the present application;

[0030] FIG3 is a front cross-sectional view of a single cell provided in an embodiment of the present application;

[0031] FIG4 is an enlarged view of the frame A in FIG3 ;

[0032] FIG5 is an enlarged view of an embodiment of the area circled at B in FIG4 ;

[0033] FIG6 is an enlarged view of another embodiment at circle B in FIG4 ;

[0034] FIG7 is an enlarged view of circle C in FIG6 ;

[0035] FIG8 is a schematic diagram of the welding deformation of the explosion-proof valve.

[0036] Figure numerals: 100 - shell, 110 - accommodating chamber, 120 - side wall, 121 - pressure relief hole, 130 - first wall, 140 - second wall, 200 - explosion-proof valve, 210 - main body, 211 - notch, 212 - elastic strain part, 213 - main body, 220 - base, 300 - cover assembly. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0038] The explosion-proof valve 200 on the single cell is a safety device that is designed to actively rupture when the inside of the single cell is over-pressurized to relieve the pressure inside the single cell, thereby preventing the single cell from exploding.

[0039] In current technology, explosion-proof valve 200 is connected to housing 100 by welding. The welding process inevitably generates heat, causing welding deformation of explosion-proof valve 200. See Figure 8, which illustrates the welding deformation of the explosion-proof valve. This welding deformation further leads to localized stress concentration, which affects the opening pressure of explosion-proof valve 200 and, in turn, reduces the safety performance of the entire single battery. Figure 8 shows that explosion-proof valve 200 has broken and failed due to welding deformation during welding to housing 100.

[0040] To solve the technical problem of welding deformation of the explosion-proof valve 200 when welding to the housing 100 in the prior art, the first embodiment of the present application provides a single cell. Referring to FIG1 , FIG1 is a top view of the single cell of the embodiment of the present application. The single battery includes a shell 100 and an explosion-proof valve 200. The shell 100 has a accommodating chamber 110. The shell 100 includes multiple side walls 120. The multiple side walls 120 are used to enclose the accommodating chamber 110; the side walls 120 have a pressure relief hole 121 connected to the accommodating chamber 110; the explosion-proof valve 200 covers the pressure relief hole 121, and the explosion-proof valve 200 includes a body 210 and a base 220. The body 210 has a notch 211. The body 210 includes an elastic strain portion 212. The elastic strain portion 212 is arranged around at least a portion of the notch 211. The base 220 surrounds the body 210 and is connected to the body 210 and the side walls 120 respectively. The elastic strain portion 212 is used to generate elastic deformation along the direction from the base 220 to the notch 211.

[0041] In the first embodiment, when the explosion-proof valve 200 is welded to the shell 100, the stress generated by the welding is converted into elastic deformation of the elastic strain portion 212, and no deformation occurs due to thermal expansion, thereby reducing the possibility of welding deformation. In other words, the possibility of changes in the opening pressure of the explosion-proof valve 200 is reduced, thereby improving the overall safety performance of the single battery.

[0042] Furthermore, the number of pressure relief holes 121 can be one or more. Referring again to Figure 1 , there are two pressure relief holes 121, and two explosion-proof valves 200 cover the two pressure relief holes 121. When a single battery cell is long, a single explosion-proof valve 200 may not be able to quickly respond to pressure changes within the cell. However, providing multiple explosion-proof valves 200 reduces the shortest distance between the pressure change point and the explosion-proof valve 200, allowing the explosion-proof valve 200 closer to the pressure change point to respond more quickly, thereby further improving the safety performance of the single battery cell.

[0043] Furthermore, when the number of explosion-proof valves 200 is greater than or equal to 3, adjacent explosion-proof valves 200 are arranged at equal intervals along the length direction of the side wall 120 to shorten the shortest distance between the explosion-proof valve 200 and the pressure change point, so that the explosion-proof valve 200 can respond more quickly to the pressure changes inside the single cell, thereby further improving the safety performance of the single cell.

[0044] Furthermore, the explosion-proof valve 200 can have the notches 211 on the body 210 connected end to end and arranged around the body 210 as needed, or can be separated end to end.

[0045] Furthermore, the base 220 includes a first connecting surface arranged in a ring along the thickness direction X of the explosion-proof valve 200 and a second connecting surface perpendicular to the thickness direction X of the explosion-proof valve 200 and connected to the first connecting surface. The first connecting surface and the second connecting surface are respectively connected to the shell 100 to increase the connection area between the explosion-proof valve 200 and the shell 100, thereby improving the connection stability between the explosion-proof valve 200 and the shell 100.

[0046] The thickness direction X of the explosion-proof valve 200 is the direction indicated by the X axis in Figures 1 to 7.

[0047] Furthermore, the housing 100 includes a first hole wall, which is used to enclose the pressure relief hole 121, wherein the first connecting surface is connected to the first hole wall.

[0048] Furthermore, the shell 100 also includes a second hole wall, which is used to enclose the pressure relief hole 121. The second hole wall is connected to the first hole wall, and the second hole wall is perpendicular to the thickness direction X of the explosion-proof valve 200, wherein the second connecting surface is connected to the second hole wall.

[0049] In the above embodiment, the connection area between the explosion-proof valve 200 and the housing 100 is increased, thereby improving the stability of the connection between the explosion-proof valve 200 and the housing 100 .

[0050] Furthermore, the base 220 and the body 210 are an integrated structure. Such a setting can improve the mechanical properties between the base 220 and the body 210, and avoid the base 220 and the body 210 being deformed and failed before the elastic strain part 212 when welding the explosion-proof valve 200, causing the explosion-proof valve 200 to rupture.

[0051] In some embodiments, please refer to Figures 5, 6 and 7, where Figure 5 is an enlarged view of an embodiment at circle B in Figure 4, Figure 6 is an enlarged view of another embodiment at circle B in Figure 4, and Figure 7 is an enlarged view of circle C in Figure 6. The elastic strain portion 212 has a minimum dimension δ along the thickness direction X of the explosion-proof valve 200, and the elastic strain portion 212 has a minimum dimension W along a direction perpendicular to the thickness direction X of the explosion-proof valve 200, satisfying: 1.5δ≤W≤5δ.

[0052] In the above embodiment, the minimum dimension W of the elastic strain portion 212 along the direction perpendicular to the thickness direction X of the explosion-proof valve 200 may be any one of 1.5δ, 1.6δ, 1.7δ, 1.8δ, 1.9δ, 2δ, 2.1δ, 2.2δ, 2.3δ, 2.4δ, 2.5δ, 2.6δ, 2.7δ, 2.8δ, 2.9δ, 3δ, 3.1δ, 3.2δ, 3.3δ, 3.4δ, 3.5δ, 3.6δ, 3.7δ, 3.8δ, 3.9δ, 4δ, 4.1δ, 4.2δ, 4.3δ, 4.4δ, 4.5δ, 4.6δ, 4.7δ, 4.8δ, 4.9δ, and 5δ, or a range between any two of the values. When W is too small, the deformation range of the elastic strain portion 212 is small. When the explosion-proof valve 200 undergoes welding deformation, the elastic strain portion 212 is insufficient to produce elastic deformation to offset the tearing or deformation of the explosion-proof valve caused by the welding deformation. When W is too large, the elastic strain portion 212 may increase the overall thickness of the explosion-proof valve 200 after elastic deformation, causing the explosion-proof valve 200 to interfere with other components in the single battery cell. Furthermore, an excessively large W may result in an excessively small valve opening area defined by the notch 211, thereby preventing the explosion-proof valve 200 from providing effective safety protection. In this embodiment, the minimum and maximum values ​​of W are limited to avoid these two situations.

[0053] The following is an example of an explosion-proof valve with a design opening pressure requirement of 0.7±0.2MPa. When δ=0.05mm remains unchanged, the technical effects of selecting different values ​​of W are as follows:

[0054] In the above comparative examples 1 and 2, the values ​​of W are 0.8δ and 1.0δ, respectively, which are less than the lower limit of the value range. After the explosion-proof valve and the shell are welded, cracks appear at the notch of the valve plate, and the explosion-proof valve fails. Because the width of the elastic strain portion is too small, the notch is too close to the welding position between the valve plate and the shell. During welding, the notch of the valve plate is affected by thermal stress and deformed, resulting in cracking and failure.

[0055] In the above Examples 1 to 8, the values ​​of W are all within the range of 1.5δ to 5δ. The welding between the explosion-proof valve and the shell is normal, and the opening pressure of the explosion-proof valve meets the design requirements. It opens normally during the thermal runaway test, the shell does not rupture, and the safety test is passed. In addition, in the eight examples of Examples 1 to 8, the values ​​of W increase in a gradient. A careful observation of the opening pressure of the explosion-proof valve reveals that as the value of W increases, the opening pressure of the explosion-proof valve gradually decreases. When the value of W is within the upper and lower limits of the range of 1.5δ to 5δ, the opening pressure is also close to the upper and lower limits of 0.7±0.2MPa. This is because when the other parameters of the explosion-proof valve remain unchanged, only the width of the elastic strain portion is gradually increased. The notch of the explosion-proof valve will be farther and farther away from the welding position between the valve plate and the shell, and the effective opening area of ​​the explosion-proof valve will also become smaller. When the thickness of the valve plate body remains unchanged, the opening pressure of the explosion-proof valve will decrease.

[0056] In the above comparative examples 3 and 4, the values ​​of W are 5.5δ and 6.0δ respectively, which are greater than the upper limit of the value range. The welding of the explosion-proof valve and the shell is normal, but the opening pressure of the explosion-proof valve is less than the lower limit of the design requirement. During the thermal runaway test, the explosion-proof valve opens prematurely. Although the shell is not broken, the premature opening of the valve cannot provide safety protection for the battery cell during use. The reason is that the width of the elastic strain part of the explosion-proof valve is too large, and the notch is too far away from the welding position of the valve plate and the shell, resulting in the opening area of ​​the explosion-proof valve being too small, and the opening pressure of the explosion-proof valve will be reduced. The following is another example of an explosion-proof valve with an opening pressure design requirement of 0.8±0.2MPa. When δ=0.1mm remains unchanged, the technical effects of selecting different values ​​of W are as follows:

[0057] In the above comparative examples 5 and 6, the values ​​of W are 0.8δ and 1.0δ, respectively, which are less than the lower limit of the value range. After the explosion-proof valve and the shell are welded, cracks appear at the notch of the valve plate, and the explosion-proof valve fails. Because the width of the elastic strain portion is too small, the notch is too close to the welding position between the valve plate and the shell. During welding, the notch of the valve plate is affected by thermal stress and deformed, resulting in cracking and failure.

[0058] In the above Examples 9 to 16, the values ​​of W are all within the range of 1.5δ to 5δ. The welding between the explosion-proof valve and the shell is normal, and the opening pressure of the explosion-proof valve meets the design requirements. It opens normally during the thermal runaway test, the shell does not rupture, and the safety test is passed. In addition, in the eight examples of Examples 9 to 16, the values ​​of W increase in a gradient. Careful observation of the opening pressure of the explosion-proof valve reveals that as the value of W increases, the opening pressure of the explosion-proof valve gradually decreases. When the value of W is within the upper and lower limits of the range of 1.5δ to 5δ, the opening pressure is also close to the upper and lower limits of 0.8±0.2MPa. This is because when the other parameters of the explosion-proof valve remain unchanged, only the width of the elastic strain portion is gradually increased. The notch of the explosion-proof valve will be farther and farther away from the welding position between the valve plate and the shell, and the effective opening area of ​​the explosion-proof valve will also decrease. When the thickness of the valve plate body remains unchanged, the opening pressure of the explosion-proof valve will decrease.

[0059] In the above comparative examples 7 and 8, the values ​​of W are 5.5δ and 6.0δ respectively, which are greater than the upper limit of the value range. The welding of the explosion-proof valve and the shell is normal, but the opening pressure of the explosion-proof valve is less than the lower limit of the design requirement. During the thermal runaway test, the explosion-proof valve opens prematurely. Although the shell is not broken, the premature opening of the valve cannot provide safety protection for the battery cell during use. The reason is that the width of the elastic strain part of the explosion-proof valve is too large, and the notch is too far away from the welding position of the valve plate and the shell, resulting in too small an opening area of ​​the explosion-proof valve, and the opening pressure of the explosion-proof valve will be reduced.

[0060] In some embodiments, referring again to FIG. 5 and FIG. 6 , the elastic strain portion 212 extends in a curved or broken line shape along a direction from the notch 211 to the base 220 .

[0061] In the above embodiment, the curved shape includes arcs, circular arcs, and wavy lines, while the broken line shape is formed by connecting multiple line segments end to end, with the angle between adjacent line segments not equal to 180°. By extending the elastic strain portion 212 in a curved or broken line shape along the direction from the notch 211 to the base 220, the elastic strain portion 212 is capable of undergoing a significant elastic deformation. This prevents welding deformation of the explosion-proof valve 200 during welding, which could lead to changes in the opening pressure of the explosion-proof valve 200, thereby improving the overall safety performance of the single battery.

[0062] Preferably, the elastic strain portion 212 extends in a curved shape along the direction from the notch 211 to the base 220. Compared with the broken line shape, the curved elastic strain portion 212 can minimize the possibility of gravitational concentration, thereby preventing the elastic strain portion 212 from rupturing after elastic deformation, thereby causing the explosion-proof valve 200 to fail.

[0063] In some embodiments, referring again to FIG. 6 and FIG. 7 , the elastic strain portion 212 extends in an arc shape along a direction from the notch 211 to the base 220 , and the radius of the arc is R, satisfying: 0.5 mm ≤ R ≤ 15 mm.

[0064] In the above embodiment, the elastic strain portion 212 extending in an arc shape has a first surface and a second surface that are opposite to each other. In some embodiments, the radius of the first surface and the second surface is the same, and one of the first surface and the second surface is obtained by translating the other along the thickness direction X of the explosion-proof valve 200. In this embodiment, the radius R can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, and 15 mm, or a range between any two values. The smaller the radius R, the smaller the elastic deformation of the elastic strain portion 212. When the radius R is too small, during the welding process, the elastic strain portion 212 may not produce enough elastic deformation to offset the tearing or deformation of the explosion-proof valve caused by welding deformation. The larger the radius R, the thicker the outer dimensions of the elastic strain portion 212, which may not only cause interference between the explosion-proof valve 200 and other components in the single battery cell, but also increase the overall thickness of the explosion-proof valve 200. Moreover, if R is too large, the notch will be too far from the welding position between the valve plate and the housing, resulting in a small opening area of ​​the explosion-proof valve and a reduced opening pressure of the explosion-proof valve. This embodiment avoids the occurrence of these two situations by limiting the minimum and maximum values ​​of the radius R.

[0065] The following is an example of an explosion-proof valve with a design opening pressure requirement of 0.8±0.2MPa. The technical effects of selecting different values ​​for R are as follows:

[0066] In the above comparative examples 9 and 10, R is 0.2 mm and 0.3 mm respectively, which is less than the lower limit of 0.5 mm to 15 mm. After the explosion-proof valve and the shell are welded, cracks appear at the notches of the valve plate, and the explosion-proof valve fails. This is because the curvature of the elastic strain portion is too small and the degree of deformation is too small. During welding, the notches of the valve plate are greatly affected by thermal stress and are prone to deformation, leading to cracking and failure.

[0067] In the above Examples 17 to 24, the R values ​​are all within the range of 0.5mm to 15mm, the welding of the explosion-proof valve and the shell is normal, and the opening pressure of the explosion-proof valve meets the design requirements. It opens normally during the thermal runaway test, the shell does not rupture, and the safety test is passed. In addition, in the above 8 examples, it is found that as the R values ​​increase, the opening pressure of the explosion-proof valve gradually decreases. When the R values ​​are within the upper and lower limits of the range of 0.5mm to 15mm, the opening pressure is also close to the upper and lower limits of 0.8±0.2MPa. This is because when the other parameters of the explosion-proof valve remain unchanged, only the curvature of the elastic strain portion is increased, that is, the larger the elastic deformation, the farther the notch of the explosion-proof valve will be from the welding position of the valve plate and the shell, and the effective opening area of ​​the explosion-proof valve will also become smaller. When the size of the valve plate body remains unchanged, the opening pressure of the explosion-proof valve will decrease.

[0068] In the above comparative examples 11 and 12, the R values ​​are 18mm and 30mm respectively, which are greater than the upper limit of the value range. The welding of the explosion-proof valve and the shell is normal, but the elastic strain part touches and interferes with the explosion-proof valve patch, so the patch is cancelled for testing. The measured opening pressure of the explosion-proof valve is less than the lower limit of the design requirement. During the thermal runaway test, the explosion-proof valve opens in advance. Although the shell is not broken, the premature opening of the valve cannot provide safety protection for the battery cell during use. The reason is that the curvature of the elastic strain part is too large. On the one hand, it interferes with the patch and affects the normal use of the cover. On the other hand, the notch is too far away from the welding position of the valve plate and the shell. The opening area of ​​the explosion-proof valve is too small, which causes the opening pressure of the explosion-proof valve to be reduced.

[0069] In other embodiments, the radii of the first and second surfaces that face away from each other are different.

[0070] In some embodiments, please refer to Figure 7 again. The main body 210 also includes a main body portion 213, the notch 211 is provided on the main body portion 213, the main body portion 213 is connected to the elastic strain portion 212, the main body portion 213 has a dimension H along the thickness direction X of the explosion-proof valve 200, and the elastic strain portion 212 has a minimum dimension δ along the thickness direction X of the explosion-proof valve 200, satisfying: δ≤H.

[0071] In the above embodiment, dimension H is the thickness of the main body 213. When the thickness of the main body 213 is inconsistent, dimension H is the minimum thickness of the main body 213. The smaller the δ value of the elastic strain portion 212, the lower the stiffness of the elastic strain portion 212, and the more easily the elastic strain portion 212 deforms. The larger the δ value of the elastic strain portion 212, the greater the stiffness of the elastic strain portion 212, and the less likely the elastic strain portion 212 deforms. In this embodiment, by limiting δ ≤ H, the elastic strain portion 212 can quickly respond to welding deformation generated by the explosion-proof valve 200 during welding, that is, generate elastic deformation to avoid welding deformation, thereby optimizing the use effect of the elastic strain portion 212 and further improving the safety performance of the explosion-proof valve 200 and the single battery.

[0072] In some embodiments, the body 210 includes a plurality of elastic strain portions 212 disposed at intervals. Among two adjacent elastic strain portions 212 , one elastic strain portion 212 is disposed around the other elastic strain portion 212 .

[0073] Furthermore, two adjacent elastic strain portions 212 both surround the notch 211 , or one of the two surrounds the notch 211 and the other is disposed around a portion of the notch 211 , or both are disposed around a portion of the notch 211 .

[0074] In order to obtain a greater degree of elastic deformation while avoiding increasing the overall thickness of the explosion-proof valve 200, in the above embodiment, a plurality of elastic strain portions 212 are provided in the direction from the notch 211 to the base 220 to increase the degree of elastic deformation, thereby further improving the reliability of the explosion-proof valve 200. This allows the elastic strain portions 212 in the above embodiment to accept a greater degree of welding deformation, and the explosion-proof valve 200 in the above embodiment can adapt to higher temperature welding processes.

[0075] In some embodiments, please refer to FIG. 2 , which is a schematic structural diagram of an explosion-proof valve 200 in a single cell provided in an embodiment of the present application, wherein the elastic strain portion 212 is disposed around the notch 211 .

[0076] In the above embodiment, because the elastic strain portion 212 surrounds the notch 211, the elastic strain portion 212 can achieve elastic deformation in the direction from any notch 211 to the base 220, thereby preventing welding deformation of the explosion-proof valve 200. In other embodiments, the elastic strain portion 212 is disposed around the notch 211. In these embodiments, the elastic strain portion 212 is specifically disposed between the notch 211 and the base 220, thereby ensuring that the elastic strain portion 212 can prevent welding deformation while improving the overall rigidity of the explosion-proof valve 200.

[0077] In some embodiments, please refer to Figures 1, 3 and 4 again. Figure 3 is a main cross-sectional view of a single cell provided in an embodiment of the present application. Figure 4 is an enlarged view of frame A in Figure 3. The shell 100 also includes a first wall 130 and a second wall 140 arranged opposite to each other, and multiple side walls 120 are arranged between the first wall 130 and the second wall 140. The first wall 130, the second wall 140 and the multiple side walls 120 are connected to enclose a accommodating cavity 110, and the area of ​​the side wall 120 is smaller than the area of ​​the first wall 130 and the second wall 140.

[0078] The first wall 130 of one of two adjacent single cells in the battery pack is opposite to the second wall 140 of the other. In order to ensure that the explosion-proof valve 200 can release pressure smoothly after opening, in the above embodiment, the explosion-proof valve 200 is arranged on the side wall 120 to ensure that the explosion-proof valve 200 can release pressure smoothly after opening. The areas of the first wall 130 and the second wall 140 are respectively larger than the area of ​​the side wall 120.

[0079] In some embodiments, referring again to FIG. 3 , the single cell further includes a cover plate assembly 300 , which is connected to the housing 100 and seals the accommodating cavity 110 . In the above embodiment, the accommodating cavity 110 has an opening, and the cover plate assembly 300 seals the opening to close the accommodating cavity 110 . In some embodiments, the accommodating cavity 110 has two opposing openings, and two cover plate assemblies 300 seal each opening. In other embodiments, the accommodating cavity 110 has a single opening, and the cover plate assembly 300 seals the opening.

[0080] In some embodiments, there are multiple sidewalls 120, and multiple explosion-proof valves 200 are located on the same sidewall 120. In other embodiments, multiple explosion-proof valves 200 are located in portions of multiple sidewalls 120. In still other embodiments, the number of explosion-proof valves 200 is evenly distributed on multiple sidewalls 120.

[0081] Accordingly, another embodiment of the present application further provides a battery pack including the above-described single battery. Because single batteries having explosion-proof valves 200 with elastic strain portions 212 provide higher safety performance, in some embodiments, the safety performance of the battery pack is improved by using single batteries having explosion-proof valves 200 with elastic strain portions 212.

[0082] In addition, the battery pack has a first direction, a second direction, and a third direction, and the first direction, the second direction, and the third direction intersect;

[0083] The battery pack has a first size L1 in a first direction, which satisfies: 100 mm ≤ L1 ≤ 600 mm, or 600 mm ≤ L1 ≤ 1500 mm;

[0084] The battery pack has a second size L2 in the second direction, satisfying: 50 mm ≤ L2 ≤ 250 mm;

[0085] The battery pack has a third dimension L3 in the third direction, satisfying: 10 mm ≤ L3 ≤ 600 mm.

[0086] In some embodiments, the first direction, the second direction, and the third direction are perpendicular to each other.

[0087] In the above embodiment, the first dimension L1 is the maximum dimension of the battery pack in the first direction, the second dimension L2 is the maximum dimension of the battery pack in the second direction, and the third dimension L3 is the maximum dimension of the battery pack in the third direction. The first dimension L1 may be any value of 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, 550 mm, or 600 mm, or a range between any two values, or may be any value of 600 mm, 650 mm, 700 mm, 750 mm, 800 mm, 850 mm, 900 mm, 950 mm, 1000 mm, 1050 mm, 1100 mm, 1150 mm, 1200 mm, 1250 mm, 1300 mm, 1350 mm, 1400 mm, 1450 mm, or 1500 mm, or a range between any two values.

[0088] Among them, the second size L2 can be: any value of 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, 500mm, 550mm, 600mm, or a range between any two values.

[0089] The third size L3 can be: 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, 310mm, Any value of 320mm, 330mm, 340mm, 350mm, 360mm, 370mm, 380mm, 390mm, 400mm, 410mm, 420mm, 430mm, 440mm, 450mm, 460mm, 470mm, 480mm, 490mm, 500mm, 510mm, 520mm, 530mm, 540mm, 550mm, 560mm, 570mm, 580mm, 590mm, and 600mm, or the range between any two values.

[0090] The larger the battery pack, the more difficult it is to arrange it inside the electrical equipment; the smaller the battery pack, the smaller its capacity.

[0091] The above is a detailed introduction to the single cell and battery pack provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application. Industrial Applicability

[0092] The single cell battery includes a shell and an explosion-proof valve. The shell has a receiving cavity and includes multiple side walls, which are used to enclose the receiving cavity. The side walls have a pressure relief hole connected to the receiving cavity. The explosion-proof valve covers the pressure relief hole. The explosion-proof valve includes a body and a base. The body has a notch. The body includes an elastic strain portion, which is arranged around at least a portion of the notch. The base surrounds the body and is connected to the body and the side walls respectively. The elastic strain portion is used to generate elastic deformation along the direction from the base to the notch. The present application provides an explosion-proof valve with an elastic strain portion in the pressure relief hole on the shell, thereby avoiding welding deformation when the explosion-proof valve is welded to the shell, thereby avoiding changes in the opening pressure of the explosion-proof valve, and further improving the safety performance of the single cell battery.

Claims

1. A single cell, characterized in that, Comprising: A housing having a receiving cavity, the housing including a plurality of side walls for enclosing the receiving cavity; the side walls having pressure relief holes communicating with the receiving cavity; An explosion-proof valve covering the pressure relief holes, the explosion-proof valve including a body and a base, the body having a score line, the body including an elastic strain portion disposed around at least a part of the score line, the base surrounding the body and being connected to the body and the side walls respectively; Wherein, the elastic strain portion is configured to generate an elastic deformation along the direction from the base to the score line; The elastic strain portion has a minimum dimension δ in the thickness direction of the explosion-proof valve, and the elastic strain portion has a minimum dimension W in a direction perpendicular to the thickness direction of the explosion-proof valve, satisfying: 1.5δ ≤ W ≤ 5δ.

2. The single cell according to claim 1, characterized in that, The elastic strain portion extends in a curved or zigzag shape along the direction from the score line to the base.

3. The single cell according to claim 2, wherein The elastic strain portion extends in an arc shape along the direction from the score line to the base, the radius of the arc shape being R, satisfying: 0.5 mm ≤ R ≤ 15 mm.

4. The single cell according to claim 1, characterized in that, The body further includes a main body portion, the score line is provided on the main body portion, the main body portion is connected to the elastic strain portion, the main body portion has a dimension H in the thickness direction of the explosion-proof valve, and the elastic strain portion has a minimum dimension δ in the thickness direction of the explosion-proof valve, satisfying: δ ≤ H.

5. The single cell according to claim 1, characterized in that, The body includes a plurality of the elastic strain portions arranged at intervals, and in two adjacent elastic strain portions, one elastic strain portion surrounds the other elastic strain portion.

6. The single cell according to claim 1, characterized in that The elastic strain portion surrounds the score line.

7. The single cell according to claim 1, wherein The housing further includes a first wall and a second wall arranged opposite to each other, the plurality of side walls are arranged between the first wall and the second wall, and the first wall, the second wall and the plurality of side walls are connected to enclose the receiving cavity, and the area of the side walls is smaller than the areas of the first wall and the second wall.

8. The single cell according to claim 1, characterized in that, The single cell further includes a cover plate assembly connected to the housing, and the cover plate assembly covers the receiving cavity.

9. A battery pack, characterized in that, Including the single cell according to any one of claims 1-8, the battery pack having a first direction, a second direction and a third direction, the first direction, the second direction and the third direction intersecting; The battery pack has a first dimension L1 in the first direction, satisfying: 100 mm ≤ L1 ≤ 600 mm, or, 600 mm ≤ L1 ≤ 1500 mm; the battery pack has a second dimension L2 in the second direction, satisfying: 50 mm ≤ L2 ≤ 250 mm; the battery pack has a third dimension L3 in the third direction, satisfying: 10 mm ≤ L3 ≤ 600 mm.

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