Batteries and battery packs

Abstract

The invention relates to the technical field of batteries, and discloses a battery and a battery pack. The battery comprises: a shell having a containing cavity; a pole group arranged in the containing cavity; an explosion-proof notch arranged on the shell to form an explosion-proof valve, wherein the explosion-proof notch comprises at least part of two semicircular segments arranged oppositely; or, the explosion-proof notch comprises two semicircular segments arranged oppositely and two straight line segments connected between the two semicircular segments, the diameter of the circle where the semicircular segments are located is d, the length of the straight line segment is L, L=nd, 0≤n≤4, wherein when n=0, the explosion-proof notch is circular; the residual thickness of the explosion-proof notch is h, the shear strength of the explosion-proof valve is τ, the opening pressure of the explosion-proof valve is p, and the diameter of the circle is 0. The battery of the invention associates the size of the explosion-proof valve with the residual thickness h of the explosion-proof notch, the shear strength τ of the explosion-proof valve, and the opening pressure p of the explosion-proof valve, thereby effectively ensuring the safety performance of the battery while taking into account the structural strength of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to batteries and battery packs. Background Art

[0002] Batteries have the risk of thermal runaway during use. In order to reduce the danger of batteries, an explosion-proof valve is provided on the battery housing. The explosion-proof valve opens when the internal air pressure of the battery rises to a certain value to discharge the high-temperature and high-pressure flue gas generated by the thermal runaway of the battery to prevent the battery from exploding. The material of the battery housing in the prior art is usually steel. The high strength of steel is conducive to ensuring the strength of the battery, reducing the damage to the housing caused by thermal runaway, and effectively preventing the housing from rupturing under high pressure. However, for the explosion-proof valve formed by notching on the housing, the higher the strength of the housing, the higher the strength of the explosion-proof valve. It is easy for the explosion-proof valve to be difficult to open or require a great pressure to open. The failure of the explosion-proof valve to open in time will bring great safety hazards to the battery. That is, the explosion-proof valve in the prior art cannot take into account both structural strength and safety performance, and it is easy to cause safety accidents. Summary of the invention

[0003] In view of this, the present invention provides a battery and a battery pack to solve the problem that the explosion-proof valve cannot take into account both structural strength and safety performance.

[0004] In a first aspect, the present invention provides a battery, comprising: a shell having a accommodating cavity; a pole group arranged in the accommodating cavity; an explosion-proof notch arranged on the shell to form an explosion-proof valve, the explosion-proof notch comprising at least a portion of two semicircular segments arranged opposite to each other; or, the explosion-proof notch comprises two semicircular segments arranged opposite to each other and two straight line segments connected between the two semicircular segments, the diameter of the circle where the semicircular segments are located is d, the length of the straight line segment is L, L=nd, wherein n is a positive number of 0 or greater than 0; the residual thickness of the explosion-proof notch is h, the shear strength of the explosion-proof valve is τ, the opening pressure of the explosion-proof valve is p, and the diameter of the circle is

[0005] Beneficial effect: By processing explosion-proof notches on the shell, the area surrounded by the explosion-proof notches forms an explosion-proof valve. The explosion-proof valve opens when the pressure in the battery reaches a preset pressure value to discharge the high-pressure gas in the battery, preventing the battery from exploding due to excessive internal pressure, thereby improving the safety of the battery. In addition, when designing the explosion-proof valve, according to the formula The size of the circle where the semicircular segment on the explosion-proof notch is located is calculated to determine the size of the explosion-proof notch, that is, the size of the explosion-proof valve is associated with the residual thickness h of the explosion-proof notch, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve. The size of the explosion-proof valve can be calculated and adjusted according to the size of the explosion-proof notch processing on the shell and the size of the performance parameters of the shell material, so that the size of the explosion-proof valve is standardized and rationalized, and the untimely exhaust due to the small size of the explosion-proof valve or the reduction of the shell strength due to the large size of the explosion-proof valve is prevented, and it is ensured that when the battery has thermal runaway, the explosion-proof valve can be opened in time and the gas in the battery can be effectively discharged, thereby reducing the risk of battery explosion, thereby effectively ensuring the safety performance of the battery while taking into account the structural strength of the battery.

[0006] In an optional embodiment, the effective area of ​​the explosion-proof valve is

[0007] Beneficial effect: The effective area of ​​the explosion-proof valve is associated with the residual thickness h of the explosion-proof notch, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve. The effective area of ​​the explosion-proof valve can be calculated according to the thickness of the explosion-proof notch and the material performance parameters of the shell, so that the effective area of ​​the explosion-proof valve is standardized and rationalized.

[0008] In an optional implementation, n is greater than 0, the explosion-proof notch is in the shape of an oblong, the diameter of the circle where the semicircular segment is located is d1, wherein the value range of d1 is 0.87 mm-17.78 mm.

[0009] Beneficial effect: By setting the diameter d1 of the circle where the upper semicircle segment of the explosion-proof notch is located to a value between 0.87mm and 17.78mm, it can be ensured that there is an exhaust channel of sufficient size when the explosion-proof valve is opened, ensuring that the gas in the battery is discharged in time, and the structural strength of the shell can be ensured, thereby ensuring that the explosion-proof valve opens normally and improving the safety performance of the battery.

[0010] In an optional embodiment, n is equal to 0, the explosion-proof notch is circular or "C"-shaped, and the diameter of the circle where the circle or "C" shape is located is The value range of d2 is 1.5mm-17.78mm.

[0011] Beneficial effect: By setting the diameter d2 of the circle to a value between 1.5 mm and 17.78 mm, it can be ensured that there is an exhaust channel of sufficient size when the explosion-proof valve is opened, ensuring that the gas in the battery is discharged in time, and the structural strength of the shell can be ensured, thereby ensuring that the explosion-proof valve opens normally and improving the safety performance of the battery.

[0012] In an optional implementation, the residual thickness h of the explosion-proof notch ranges from 0.03 mm to 0.08 mm.

[0013] Beneficial effect: It can ensure that the explosion-proof valve will not be opened prematurely and can also ensure that the explosion-proof valve can be opened in time, thereby ensuring the safety performance of the battery.

[0014] In an optional implementation, the shear strength τ of the explosion-proof valve ranges from 25 Mp to 50 Mpa.

[0015] Beneficial effect: It can ensure that the explosion-proof valve will not be opened prematurely and can also ensure that the explosion-proof valve can be opened in time, thereby ensuring the safety performance of the battery.

[0016] In an optional implementation, the opening pressure p of the explosion-proof valve is in the range of 0.9 MPa-2.0 MPa.

[0017] Beneficial effect: It can ensure that the explosion-proof valve will not be opened prematurely and delay in opening the explosion-proof valve can be avoided, thereby ensuring the safety performance of the battery.

[0018] In an optional implementation, the number of the explosion-proof valves is one or more; and / or the shell is made of steel.

[0019] Beneficial effects: The steel shell has high strength, which is beneficial to improving the structural strength of the battery and improving the battery's anti-collision performance.

[0020] In an optional embodiment, the housing includes: a shell and a cover plate, the shell has an open end, the cover plate is arranged at the open end to close the shell, and the explosion-proof notch is arranged on the cover plate and / or the shell.

[0021] Beneficial effect: By setting explosion-proof notches on the shell and / or the cover plate, the processing is simple and the design layout is highly flexible.

[0022] In a second aspect, the present invention further provides a battery pack, comprising: the above-mentioned battery. Since the battery pack comprises the battery and has the same effect as the battery, it will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of a battery according to an embodiment of the present invention;

[0025] Figure 2A schematic diagram of the structure of another battery according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of an oblong explosion-proof notch according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the structure of a circular explosion-proof notch according to an embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 1. Explosion-proof notch; 101. Semicircular segment; 102. Straight segment; 2. Shell; 3. Cover plate. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] Combine the following Figures 1 to 4 , describing an embodiment of the present invention.

[0032] According to an embodiment of the present invention, on the one hand, a battery is provided, comprising: a shell, a pole group and an explosion-proof notch 1. The shell has a receiving cavity; the pole group is arranged in the receiving cavity; the explosion-proof notch 1 is arranged on the shell to form an explosion-proof valve, and the explosion-proof notch 1 includes at least part of two semicircular segments 101 arranged opposite to each other; or, the explosion-proof notch 1 includes two semicircular segments 101 arranged opposite to each other and two straight segments 102 connected between the two semicircular segments 101, the diameter of the circle where the semicircular segments 101 are located is d, the length of the straight segment 102 is L, L=nd, wherein n is a positive number of 0 or greater than 0; the residual thickness of the explosion-proof notch 1 is h, the shear strength of the explosion-proof valve is τ, the opening pressure of the explosion-proof valve is p, and the diameter of the circle is When n=0, the explosion-proof notch 1 is circular.

[0033] In the battery of this embodiment, an explosion-proof notch 1 is processed on the outer shell, and an explosion-proof valve is formed in the area surrounded by the explosion-proof notch 1. The explosion-proof valve opens when the pressure in the battery reaches a preset pressure value to discharge the high-pressure gas in the battery, thereby preventing the battery from exploding due to excessive internal pressure, thereby improving the safety of the battery. In addition, when designing the explosion-proof valve, according to the formula The size of the circle where the semicircular segment 101 on the explosion-proof notch 1 is located is calculated, so as to determine the size of the area enclosed by the explosion-proof notch 1, that is, the size of the explosion-proof valve is associated with the residual thickness h of the explosion-proof notch 1, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve. The size of the explosion-proof valve can be calculated and adjusted according to the size of the processing size of the explosion-proof notch 1 on the shell and the size of the performance parameters of the shell material, so that the size of the explosion-proof valve is standardized and rationalized, and the untimely exhaust due to the small size of the explosion-proof valve or the reduction of the shell strength due to the large size of the explosion-proof valve is prevented, and it is ensured that when the battery has thermal runaway, the explosion-proof valve can be opened in time and the gas in the battery can be effectively discharged, thereby reducing the risk of battery explosion, thereby effectively ensuring the safety performance of the battery while taking into account the structural strength of the battery.

[0034] It should be noted that the explosion-proof notch 1 is stamped integrally with the shell, the residual thickness h of the explosion-proof notch 1 is the size of the solid part remaining after the explosion-proof notch 1 is stamped along the thickness direction of the shell, the shear strength τ of the explosion-proof valve is the material performance parameter of the shell provided with the explosion-proof valve, and the opening pressure p of the explosion-proof valve is the critical value for the opening of the explosion-proof valve, which reflects the performance of the shell. The above parameters can be selected based on experience, and then the size of the explosion-proof notch 1 is calculated and determined based on the selected performance parameters, so that the size of the explosion-proof notch 1 has a constant basis, thereby preventing the traditional method of determining the size of the explosion-proof valve based only on empirical values, which causes a mismatch with the actual performance of the battery.

[0035] In one embodiment, the effective area of ​​the explosion-proof valve is It should be noted that the effective area of ​​the explosion-proof valve refers to the area of ​​the area enclosed by the explosion-proof notch, which is also the effective cross-sectional area of ​​the passage used for exhaust after the explosion-proof valve is opened. The effective area of ​​the explosion-proof valve is related to the residual thickness h of the explosion-proof notch 1, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve. The effective area of ​​the explosion-proof valve can be calculated based on the thickness of the explosion-proof notch 1 and the material performance parameters of the shell, so that the effective area of ​​the explosion-proof valve is standardized and rationalized. Furthermore, since the explosion-proof valve is at least partially circular or oblong, combined with Figure 3 to Figure 4 As shown, the effective area of ​​the explosion-proof valve can be obtained by the formula Calculate, then according to It can be deduced That is, the expression of the diameter of the circle or the diameter of the circle where the upper semicircle segment 101 of the oblong is located is obtained. Wherein, L is the length of the straight line segment 102 connecting the two semicircle segments 101, L=nd, 0≤n≤4.

[0036] In one embodiment, Figure 3As shown, n is greater than 0, the explosion-proof notch 1 is an oblong, and the diameter of the circle where the semicircle segment 101 is located is d1, wherein the value range of d1 is 0.87mm-17.78mm. The oblong is composed of a semicircle segment 101, a straight line segment 102, a semicircle segment 101, and a straight line segment 102 connected end to end in sequence, two semicircle segments 101 are arranged oppositely, two straight line segments 102 are arranged oppositely, and the two straight line segments 102 are parallel, and the two ends of each straight line segment 102 are respectively connected to one end of a semicircle segment 101, and the diameter of the circle where the semicircle segment 101 is located is According to the residual thickness h of the explosion-proof notch 1, the shear strength τ of the explosion-proof valve, the opening pressure p of the explosion-proof valve, and the value of n, the size of d1 can be calculated. Further, according to L=nd, the length of the straight segment 102 can be obtained, thereby determining the sizes of the explosion-proof notch 1. If d1 is less than 0.87 mm, the diameter of the semicircular segment 101 is too small, and correspondingly, the length of the straight segment 102 is too small, that is, the size of the explosion-proof valve is too small, resulting in a cross-sectional area of ​​the effective exhaust channel when the explosion-proof valve is opened. It is impossible to discharge the gas in the battery in time, and there is a risk of battery explosion; if d1 is greater than 17.78 mm m, the diameter of the semicircular segment 101 is too large, and correspondingly, the length of the straight segment 102 is too large, that is, the size of the explosion-proof valve is too large, and the effective supporting area of ​​the shell except the explosion-proof valve is too small, which reduces the strength of the shell. Therefore, when the explosion-proof notch 1 is an oblong, by setting the diameter d1 of the circle where the semicircular segment 101 on the explosion-proof notch 1 is located to a value between 0.87mm and 17.78mm, it can be ensured that there is an exhaust channel of sufficient size when the explosion-proof valve is opened, ensuring that the gas in the battery is discharged in time, and ensuring the structural strength of the shell, thereby ensuring that the explosion-proof valve is opened normally and improving the safety performance of the battery.

[0037] In another embodiment, Figure 4 As shown, n is equal to 0, the explosion-proof notch 1 is circular, and the diameter of the circle is The value range of d2 is 1.5mm-17.78mm. It should be noted that when n=0, L=nd=0, that is, the explosion-proof notch 1 does not include the straight line segment 102, and the explosion-proof notch 1 is formed by splicing two semicircular segments 101. The explosion-proof notch 1 is circular, and the circular structure is simple and easy to process. Substituting n=0 into the formula In, we can get The size of d2 can be calculated according to the residual thickness h of the explosion-proof notch 1, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve, thereby determining the size of the explosion-proof valve. If d2 is less than 1.5 mm, the diameter of the circular explosion-proof valve is too small, resulting in a cross-sectional area of ​​the effective exhaust channel when the explosion-proof valve is opened that is too small, and the gas in the battery cannot be discharged in time, posing a risk of battery explosion; if d2 is greater than 17.78 mm, the diameter of the circular explosion-proof valve is too large, and the effective supporting area on the shell except for the explosion-proof valve is too small, reducing the strength of the shell. Therefore, when the explosion-proof notch 1 is circular, by setting the diameter d2 of the circle to a value between 1.5 mm and 17.78 mm, it can be ensured that there is an exhaust channel of sufficient size when the explosion-proof valve is opened, ensuring that the gas in the battery is discharged in time, and ensuring the structural strength of the shell, thereby ensuring that the explosion-proof valve opens normally and improving the safety performance of the battery. It can be understood that, as a replaceable embodiment, the explosion-proof notch 1 can also be in a "C" shape, that is, a partial circle, and the diameter of the circle where the "C" shape is located is d2. When the "C"-shaped explosion-proof notch 1 is opened, the exhaust channel is also circular, and the performance is the same as the above-mentioned circular explosion-proof notch.

[0038] In one embodiment, the outer shell is made of steel. The steel shell has high strength, which is beneficial to improving the structural strength of the battery and improving the anti-collision performance of the battery.

[0039] In one embodiment, the residual thickness h of the explosion-proof notch 1 has a value range of 0.03mm-0.08mm. The residual thickness h of the explosion-proof notch 1 is the thickness of the effective entity part corresponding to the explosion-proof notch 1. If the residual thickness h of the explosion-proof notch 1 is less than 0.03mm, the thickness of the entity part is too small, and the explosion-proof notch 1 is easy to break, and the explosion-proof valve may open in advance before the air pressure in the battery reaches the preset pressure value, affecting the life of the battery; if the residual thickness h of the explosion-proof notch 1 is greater than 0.08mm, the thickness of the entity part is too large, the difficulty of breaking at the explosion-proof notch 1 increases, and the pressure value required to open the explosion-proof valve increases, and the explosion-proof valve may not open in time, thereby causing the battery to explode due to excessive internal pressure, which is very dangerous. Therefore, by setting the residual thickness h of the explosion-proof notch 1 to a value between 0.03mm-0.08mm, it can be ensured that the explosion-proof valve will not open in advance, and the explosion-proof valve can be opened in time, thereby ensuring the safety performance of the battery. Specifically, the score residual thickness h of the steel explosion-proof valve can be 0.03mm, 0.04mm, 0.055mm, 0.075mm, 0.08mm, etc.

[0040] In one embodiment, the shear strength τ of the explosion-proof valve has a value range of 25Mp-50Mpa. Shear strength characterizes the ability of a material to resist shear load without failure, and is the material property of the shell itself. If the shear strength is less than 25Mp, the shear strength of the explosion-proof valve is too small, and the explosion-proof notch 1 will fail when the air pressure in the battery does not reach the preset pressure value, and the explosion-proof valve will open in advance, affecting the life of the battery; if the shear strength is greater than 50Mpa, the shear strength of the explosion-proof valve is too large, the difficulty of breaking at the explosion-proof notch 1 increases, and the pressure value required to open the explosion-proof valve increases, and the explosion-proof valve cannot be opened in time, resulting in the battery exploding due to excessive internal pressure, which is very dangerous. Therefore, by setting the shear strength τ of the explosion-proof valve to a value between 25Mp-50Mpa, it can be ensured that the explosion-proof valve will not open in advance, and the explosion-proof valve can be opened in time, thereby ensuring the safety performance of the battery.

[0041] Specifically, the shear strength τ of the steel explosion-proof valve can be 25Mpa, 30Mpa, 38Mpa, 45Mpa, 50Mpa, etc.

[0042] In one embodiment, the opening pressure p of the explosion-proof valve has a value range of 0.9Mpa-2.0Mpa. The opening pressure p of the explosion-proof valve is the critical value for the explosion-proof valve to open. When the gas pressure in the battery is less than the critical value, the explosion-proof valve does not open, and when the gas pressure in the battery is greater than or equal to the critical value, the explosion-proof valve opens to prevent the battery from exploding, which reflects the performance of the shell. If the opening pressure of the explosion-proof valve is less than 0.9Mpa, the opening pressure value is too small, and the explosion-proof valve opens too early, affecting the service life of the battery; if the opening pressure of the explosion-proof valve is greater than 2.0Mpa, the opening pressure value is too large, and the explosion-proof valve is difficult to open. If the explosion-proof valve cannot be opened in time, the risk of battery explosion is increased. Therefore, by setting the opening pressure p of the explosion-proof valve to a value of 0.9Mpa-2.0Mpa, it can be ensured that the explosion-proof valve will not open in advance, and the explosion-proof valve can be prevented from opening late, thereby ensuring the safety performance of the battery.

[0043] Specifically, the opening pressure p of the steel explosion-proof valve can be 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.5 MPa, 2.0 MPa, etc.

[0044] In one embodiment, the number of explosion-proof valves is one or more. The number of explosion-proof valves can be designed according to actual needs, and can be one, two, three or more.

[0045] In one embodiment, the housing includes: a shell 2 and a cover plate 3, the shell 2 has an open end, the cover plate 3 is arranged at the open end to close the shell 2, and the explosion-proof notch 1 is arranged on the cover plate 3 and / or the shell 2. Preferably, the explosion-proof notch 1 is arranged on the cover plate 3, and the explosion-proof notch 1 and the cover plate 3 are integrally stamped and formed, which is convenient for layout and processing. It can be understood that, as a replaceable embodiment, the explosion-proof notch 1 can also be arranged on the shell 2, and the explosion-proof notch 1 and the shell 2 are integrally formed, which can also realize the function of the explosion-proof valve; of course, the explosion-proof notch 1 can also be arranged on both the shell 2 and the cover plate 3 to increase the exhaust area when the explosion-proof valve is opened. By arranging the explosion-proof notch 1 on the shell 2 and / or the cover plate 3, the processing is simple and the design layout flexibility is high.

[0046] Preferably, the battery is a cylindrical battery, and the cover plate 3 is circular. Further preferably, the explosion-proof notch 1 can be designed as follows: Figure 1 As shown in the circular or Figure 2 The "C" shape shown matches the shape of the cover plate 3 and is easy to process.

[0047] The following describes the test results of thermal runaway tests on different batteries for experimental verification.

[0048] For batteries with a circular or "C"-shaped explosion-proof notch 1, the test results are shown in Table 1:

[0049] Table 1 Thermal runaway test results of the embodiment and comparative example It can be seen from Table 1 that for the batteries of Examples 1 to 10, the shear strength τ of the explosion-proof valve is within the range of 25Mp-50Mpa, the opening pressure p of the explosion-proof valve is within the range of 0.9Mpa-2.0Mpa, the residual thickness h of the explosion-proof notch 1 is within the range of 0.03mm-0.08mm, and the calculated result of the circular diameter d2 is within the range of 1.5mm-17.78mm. The explosion-proof valves of the batteries of Examples 1 to 10 are all opened normally and the shells are not broken, and can pass the thermal runaway test.

[0050] However, in Comparative Examples 1 and 5, the shear strength τ of the explosion-proof valve is less than 25Mp, and the calculated results of the circular diameter d2 are less than 1.5mm, which are not within the range specified in this application (1.5mm-17.78mm). The battery shear strength of Comparative Examples 1 and 5 is too small, and d2 is less than the minimum value of the specified range. Although the explosion-proof valve can be opened, the area of ​​the explosion-proof valve is too small, the exhaust is not timely, the battery explodes, the shell ruptures, and the thermal runaway test fails. In Comparative Examples 2, 4, 6, and 8, the opening pressure p of the explosion-proof valve is greater than 2.0Mpa, and the calculated results of the circular diameter d2 are less than 1.5mm, which are not within the range specified in this application. 2. The opening pressure p of the explosion-proof valve specified by the batteries of Comparative Examples 4, 6 and 8 is too large, d2 is less than the minimum value of the specified range, the explosion-proof valve fails to open in time, the battery explodes, the shell ruptures, and the thermal runaway test fails; in Comparative Examples 3 and 7, the residual thickness h of the explosion-proof notch 1 is greater than 0.08 mm, and the calculated results of the circular diameter d2 are greater than 17.78 mm, which are not within the range specified in the present application. The circular diameter d2 of the explosion-proof valve of the batteries of Comparative Examples 3 and 7 is greater than the maximum value of the specified range, the residual thickness h of the explosion-proof notch 1 is too large, the explosion-proof valve becomes more difficult to open, the explosion-proof valve fails to open in time, the battery explodes, the shell ruptures, and the thermal runaway test fails.

[0051] In summary, when the calculated result of the circular diameter d2 falls within the range specified in this application, the battery thermal runaway test can pass, which not only ensures the structural strength of the battery, but also ensures the safety performance of the battery.

[0052] For the battery with the explosion-proof notch 1 in an oblong shape, the test results are shown in Table 2:

[0053] Table 2 Thermal runaway test results of the embodiment and comparative example

[0054]

[0055] It can be seen from Table 2 that for the batteries of Examples 11 to 20, the shear strength τ of the explosion-proof valve is within the range of 25Mp-50Mpa, the opening pressure p of the explosion-proof valve is within the range of 0.9Mpa-2.0Mpa, the residual thickness h of the explosion-proof notch 1 is within the range of 0.03mm-0.08mm, the value of n is within the range of 0-4, and the calculated result of the circular diameter d1 where the semicircular segment 101 in the oblong is located is within the range of 0.87mm-17.78mm. The explosion-proof valves of the batteries of Examples 11 to 20 are all opened normally and the shell is not broken, and can pass the thermal runaway test; however, in Comparative Example 9, the shear strength τ of the explosion-proof valve is less than 25Mp, and the calculated result of the circular diameter d1 where the semicircular segment 101 is located is less than 0.87mm, which is not within the range specified in the present application. The shear strength of the battery in Comparative Example 9 is too small, and d1 The residual thickness h of the explosion-proof notch 1 is less than 0.03 mm, and the calculated result of the circular diameter d1 where the semicircular segment 101 is located is less than 0.87 mm, which is not within the scope defined in this application. The residual thickness h of the explosion-proof notch 1 of the battery in Comparative Example 10 is too small, and d1 is less than the minimum value of the specified range. Although the explosion-proof valve can be opened, the area of ​​the explosion-proof valve is too small, and the exhaust is not timely, the battery explodes, the shell ruptures, and the thermal runaway test fails. In Comparative Example 11, the value of n is greater than 4, and the calculated result of the circular diameter d1 where the semicircular segment 101 is located is less than 0. 87mm, which is not within the scope defined in the present application. The size of the straight line segment 102 in the oblong is too large, and d1 is less than the minimum value of the defined range. Although the explosion-proof valve can be opened, the size of the explosion-proof valve in the direction perpendicular to the straight line segment 102 is small, that is, the explosion-proof valve is narrow, and the exhaust patency is poor. The gas inside the battery cannot be discharged in time, the battery explodes, the shell ruptures, and the thermal runaway test fails. In Comparative Example 12, the opening pressure p of the explosion-proof valve is less than 0.9Mpa, and the calculated result of the diameter d1 of the circle where the semicircular segment 101 is located is greater than 17.78mm, which is not within the scope defined in the present application. The opening pressure p of the explosion-proof valve defined by the battery in Comparative Example 12 is too small, and d1 is greater than the maximum value of the defined range. The explosion-proof valve is The battery opens in advance before reaching the critical condition of thermal runaway, which affects the product life; in Comparative Example 13, the shear strength τ of the explosion-proof valve is less than 25Mp, in Comparative Example 14, the opening pressure p of the explosion-proof valve is greater than 2Mpa, and in Comparative Example 15, the value of n is greater than 4. The calculated results of the circular diameter d1 of the semicircular segment 101 of the battery in Comparative Examples 13 to 15 are all less than 0.87mm, which is not within the scope specified in this application. Although the explosion-proof valve can be opened, the area of ​​the explosion-proof valve is too small, the exhaust is not timely, the battery explodes, the shell ruptures, and the thermal runaway test fails; in Comparative Example 16, the opening pressure p of the explosion-proof valve is less than 0.9Mpa, and the calculated result of the circular diameter d1 of the semicircular segment 101 is greater than 17.78mm, which is not within the scope defined in this application. The explosion-proof valve of the battery in Comparative Example 16 opens in advance when the battery does not reach the critical condition of thermal runaway, which affects the product life.

[0056] In summary, when the calculated result of the circular diameter d1 falls within the range specified in this application, the battery thermal runaway test can pass and the battery service life will not be shortened, which not only ensures the structural strength of the battery, but also ensures the safety performance of the battery.

[0057] In this embodiment, a steel explosion-proof valve is provided on the shell. The size of the explosion-proof valve is calculated by controlling the residual thickness h of the explosion-proof valve, the shear strength τ of the explosion-proof valve and the opening pressure p of the explosion-proof valve, so that the shell will not rupture during the operation of the battery and the explosion-proof valve can be opened normally when the battery is thermally runaway, thereby solving the problem that the existing valve cannot take into account both structural strength and safety performance and is prone to cause safety accidents, thereby ensuring the safe operation of the battery.

[0058] According to an embodiment of the present invention, in another aspect, a battery pack is provided, comprising the above-mentioned battery. The battery pack comprises a plurality of batteries, and the batteries are preferably power batteries.

[0059] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery, characterized in that: include: A housing having a receiving cavity; A pole group, arranged in the accommodating cavity; An explosion-proof notch is arranged on the housing to form an explosion-proof valve, wherein the explosion-proof notch includes at least a portion of two semicircular segments arranged opposite to each other; or the explosion-proof notch includes two semicircular segments arranged opposite to each other and two straight line segments connected between the two semicircular segments; The diameter of the circle where the semicircle segment is located is d, the length of the straight line segment is L, and L=nd is satisfied, where n is a positive number that is 0 or greater than 0; The residual thickness of the explosion-proof notch is h, the shear strength of the explosion-proof valve is τ, the opening pressure of the explosion-proof valve is p, and the diameter of the circle is When n is greater than 0, the explosion-proof notch is in the shape of an oblong circle, and the diameter of the circle where the semicircular segment is located is d1, wherein the value range of d1 is 0.87 mm-17.78 mm; When n is equal to 0, the explosion-proof notch is circular or "C" shaped, and the diameter of the circle where the circle or "C" shape is located is The value range of d2 is 1.5mm-17.78mm; The residual thickness h of the explosion-proof notch has a value range of 0.03 mm to 0.08 mm; the shear strength τ of the explosion-proof valve has a value range of 25 MPa to 50 MPa; and the opening pressure p of the explosion-proof valve has a value range of 0.9 MPa to 2.0 MPa.

2. The battery according to claim 1, characterized in that The effective area of ​​the explosion-proof valve 3. The battery according to claim 1 or 2, characterized in that: The number of the explosion-proof valves is one or more; and / or the shell is made of steel.

4. The battery according to claim 1 or 2, characterized in that: The housing comprises: a shell and a cover plate, the shell has an open end, the cover plate is arranged at the open end to close the shell, and the explosion-proof notch is arranged on the cover plate and / or the shell.

5. A battery pack, characterized in that: include: The battery according to any one of claims 1 to 4.

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