Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer, a battery and a power utilization device, the battery monomer comprises a shell, a battery cell and an anti-explosion valve, and the battery cell is arranged in the shell; the anti-explosion valve is formed by stamping at least part of the shell and comprises a fixing part, a side wall part and a main body part which are connected in sequence; the fixing part is connected with the shell, and the main body part is arranged to face the exhaust direction so as to bear gas pressure; the side wall part extends upwards in the direction away from the interior of the battery cell or extends downwards in the direction close to the interior of the battery cell relative to the main body part, the appearance of the side wall part is of a closed annular structure, and at least one of the inner wall or the outer wall of the side wall part is provided with a concave first groove; forming a first weak part on the side wall part; according to the explosion-proof valve, the technical problems that the explosion-proof valve has a relatively accurate explosion value in a low-cost manner and the manufacturing cost of the battery monomer can be greatly reduced are mainly solved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery monomer, a battery and an electrical device. Background Art

[0002] The explosion-proof valve can be used to open the valve and release pressure in time when the battery cell is thermally runaway, so as to reduce the risk of explosion and ensure the safety of the battery system. Figure 1 As shown, in the prior art, the notch 10 of the explosion-proof valve is mostly arranged on the large surface of the main body 23, that is, the concave direction of the notch 10 is vertically directed to the inside of the battery cell (the notch 10 can be as shown in FIG. Figure 1 As shown, the outer wall of the main body 23 is recessed inwardly toward the interior of the battery cell, or the notch 10 may be recessed outwardly on the inner wall of the main body 23 away from the interior of the battery cell). When the air pressure inside the battery cell increases, the main body 23 of the explosion-proof valve bulges and deforms due to the air pressure because it is relatively thin. When the main body 23 is compressed and deformed along the vertical Z direction, there will be a component of force in the width direction parallel to the notch 10. When the deformation is large, the main body 23 will be broken at the notch 10. Because of the influence of the deformation of the main body 23, the bursting value at the notch 10 is extremely unstable, and it is difficult to control the accuracy of the bursting value at the notch 10. In order to make the bursting value at the notch 10 more accurate, the prior art usually uses MFX2 as the material for the explosion-proof valve. MFX2 is a kind of aluminum alloy, and its force consistency is good, the deformation is relatively regular, and the thickness of the stamped notch 10 can also be ensured to be relatively uniform. Therefore, the tensile strength of each position at the notch 10 is not much different. Therefore, the range of the bursting value of the explosion-proof valve made of MFX2 material is small, that is, the bursting value of the explosion-proof valve is more accurate. On the contrary, the range of the bursting value of the notch 10 stamped out of other aluminum alloy materials is larger. However, the cost of MFX2 is relatively high, and the battery shell (on which a pole serving as a positive electrode or a negative electrode is usually provided) is usually made of Al 3003 or other low-cost aluminum alloys. Therefore, the material of the explosion-proof valve is different from that of the battery shell, resulting in the need to weld the explosion-proof valve currently made of MFX2 material to the battery shell. When the cost of the explosion-proof valve made of MFX2 material is relatively high, the newly added welding process will further increase the cost, making the cost of the battery monomer even higher. Utility Model Content

[0003] The purpose of the utility model is to provide a battery cell, a battery and an electrical device, mainly to solve the technical problem of how to achieve a relatively accurate explosion value of an explosion-proof valve in a low-cost manner and also significantly reduce the manufacturing cost of the battery cell.

[0004] To achieve this purpose, the utility model adopts the following technical solutions:

[0005] A battery cell comprises a shell, a battery core and an explosion-proof valve; the battery core is arranged in the shell;

[0006] The explosion-proof valve is formed by stamping at least a portion of the shell, and includes a fixing portion, a side wall portion and a main body portion which are connected in sequence; the side wall portion is a closed annular structure, and at least one wall surface of the inner wall or the outer wall of the side wall portion is provided with a first weak portion, and the fixing portion is connected to the shell.

[0007] In one of the technical solutions, the shell includes an outer shell and a top cover, the outer shell is provided with a receiving groove, the battery cell is accommodated in the receiving groove, the top cover is connected to the outer shell and seals the notch of the receiving groove, the explosion-proof valve is formed by stamping at least part of the top cover, and the fixing part is connected to the top cover.

[0008] In one of the technical solutions, a first groove is provided on the inner wall or the outer wall of the side wall portion, and the first weak portion is formed on the side wall portion at a position corresponding to the first groove.

[0009] In one of the technical solutions, the width W of the notch of the first groove is less than or equal to 3 mm, and W is greater than or equal to 0.1 mm.

[0010] In one of the technical solutions, the thickness F of the fixing portion satisfies 0.3≤F≤3 mm, and the thickness G of the main body portion satisfies 0.1≤G≤1.5 mm.

[0011] In one technical solution, the thickness C of the side wall portion satisfies 0.1≤C≤1.5mm, the thickness D of the weakest portion in the first weak portion satisfies ≤0.8C, and the thickness E of the strongest portion in the first weak portion satisfies 1.2D≤E≤1C.

[0012] In one of the technical solutions, the angle α between the side wall portion and the fixing portion is 60°~150°, α is preferably 75°~135°, and α is more preferably 90°.

[0013] In one of the technical solutions, the distance between the first weak portion and the main body portion is less than or equal to 3 mm and greater than or equal to 0.3 mm.

[0014] In one of the technical solutions, a second weak portion is provided on the outer wall or the inner wall of the fixing portion, and the bursting value of the second weak portion is greater than the bursting value of the first weak portion.

[0015] In one of the technical solutions, a second groove is provided on the inner wall or the outer wall of the fixing portion, and the second weak portion is formed at a position of the fixing portion corresponding to the second groove.

[0016] In one of the technical solutions, the distance from the main body to the battery cell is greater than the distance from the fixing portion to the battery cell.

[0017] In one of the technical solutions, the shell is provided with a support wall on the outer side of the side wall portion, and the fixing portion is connected to the support wall, so that the support wall, the fixing portion and the side wall portion jointly surround a recessed groove.

[0018] In one of the technical solutions, the width of the recessed groove is less than or equal to 10 mm.

[0019] In one of the technical solutions, the distance from the end surface of the support wall away from the fixing portion to the fixing portion is greater than the distance from the first weak portion to the fixing portion.

[0020] In one of the technical solutions, the battery cell further includes a flame retardant filled in the recessed groove, the flame retardant abuts against the outer wall of the support wall and the side wall at the same time, and the top surface of the flame retardant is higher than the height position of the first weak portion.

[0021] In one of the technical solutions, the main body is lower than the opening of the recessed groove, and the battery cell also includes a waterproof and breathable membrane fixed on the shell. The waterproof and breathable membrane is located above the explosion-proof valve and covers the opening of the recessed groove, and there is a gap between the waterproof and breathable membrane and the main body.

[0022] In one of the technical solutions, the first weak portion is formed by providing a first groove on a side of the side wall portion facing away from the supporting wall.

[0023] The present application also provides a battery, comprising the battery cell described above.

[0024] The present application also provides an electrical device, comprising the battery described above.

[0025] Compared with the prior art, the battery cell provided by the utility model has at least the following beneficial effects:

[0026] The pressure relief principle of the battery cell of this scheme is: the main body of the explosion-proof valve is subjected to air pressure in the vertical Z direction. As long as the pressure on the main body in the vertical Z direction reaches a preset value, regardless of whether the main body is greatly deformed, the first weak part on the side wall will break immediately to achieve the purpose of pressure relief. In other words, the present solution arranges the first weak portion on the side wall portion so that the accuracy of the burst value of the first weak portion has nothing to do with the degree of deformation of the main body portion, that is, even if the main body portion is greatly deformed, it will not have a significant impact on the accuracy of the burst value of the first weak portion, thereby improving the accuracy of the burst value of the explosion-proof valve; and, since the accuracy of the burst value of the first weak portion has nothing to do with the degree of deformation of the main body portion, the explosion-proof valve can be made of low-cost Al 3003 or other low-cost aluminum alloys, which reduces the manufacturing cost of the explosion-proof valve while achieving a relatively accurate burst value, thereby reducing the cost of the battery cell; in particular, when the material of the explosion-proof valve is the same as that of the battery shell, the explosion-proof valve can be directly obtained by stamping the battery shell, thereby abandoning the welding process of welding the explosion-proof valve to the shell, so as to further reduce the manufacturing cost of the battery cell, and at the same time, the production efficiency of the battery cell can be greatly improved due to the abandonment of the welding process;

[0027] Furthermore, since the side wall of the explosion-proof valve is arranged on one side of the main body, the force area of ​​the side wall subjected to the internal gas pressure of the battery core is small, and since the shape of the side wall is a closed annular structure, the deformation of the side wall is very small, and the side wall with very small deformation will hardly have much influence on the accuracy of the explosion value of the first weak part, thereby ensuring that the explosion-proof valve has a more accurate explosion value;

[0028] In addition, since the weak part of the prior art is designed on the main body, it is easy to be burned through by the direct impact of hot gas in a high temperature environment (such as a battery module integrating more battery cells), while the first weak part of the explosion-proof valve of the present solution is hidden on the side wall, so the first weak part is not easy to be burned through at high temperature, thereby improving the safety of the battery. Moreover, the thickness of the main body of the present solution has nothing to do with the accuracy of the explosion value of the first weak part. Therefore, the main body of the present solution can be designed to be thicker to improve the structural strength of the main body to avoid the main body being burned through at high temperature, thereby further improving the safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the pressure relief principle of an explosion-proof valve in the prior art;

[0031] Figure 2 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0032] Figure 3 for Figure 2 A first cross-sectional view of the top cover at the explosion-proof valve is shown;

[0033] Figure 4 for Figure 2 A second cross-sectional view of the top cover at the explosion-proof valve is shown;

[0034] Figure 5 for Figure 2 A third cross-sectional view of the top cover at the explosion-proof valve is shown;

[0035] Figure 6 for Figure 2 A fourth cross-sectional view of the top cover at the explosion-proof valve is shown;

[0036] Figure 7 for Figure 2 A fifth cross-sectional view of the top cover at the explosion-proof valve is shown;

[0037] Figure 8 for Figure 7 The schematic diagram of the structure when a waterproof and breathable membrane is added to the top cover shown;

[0038] Fig. 9 for Figure 2 A sixth cross-sectional view of the top cover at the explosion-proof valve is shown;

[0039] Fig.10 A schematic structural diagram of the first method for forming an explosion-proof valve provided in an embodiment of the present application during implementation;

[0040] Fig.11 A schematic structural diagram of the specific implementation of step S1 in the first method for forming an explosion-proof valve provided in an embodiment of the present application;

[0041] Fig.12 A schematic structural diagram of the second method for forming an explosion-proof valve provided in an embodiment of the present application during implementation;

[0042] Fig.13 for Figure 4 A partial enlarged view of point A in the middle.

[0043] Among them, the reference numerals in the figure are:

[0044] 10. Scratching;

[0045] 1. Top cover; 11. Positive pole; 12. Negative pole; 13. Support wall; 14. Concave portion;

[0046] 2. explosion-proof valve; 21. fixing part; 211. second groove; 212. second weak part; 22. side wall; 221. first groove; 2211. engraved line; 222. first weak part; 23. main body;

[0047] 3. Recessed groove; 31. Opening; 4. Flame retardant; 5. Waterproof breathable membrane; 61. First upper mold; 611. First main body; 612. First boss; 62. First lower mold; 621. Second main body; 622. Second boss; 63. Second upper mold; 64. Second lower mold; 641. Second protrusion; 7. Molding drive member; 71. First protrusion; 81. Third upper mold; 82. Third lower mold; 83. Fourth upper mold; 84. Fourth lower mold; 85. Fifth upper mold; 86. Fifth lower mold; 20. Shell; 100. Case. DETAILED DESCRIPTION

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0049] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0050] It should be understood that the orientations or positional relationships indicated by terms such as "upper", "lower", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0052] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0053] Please also read Figure 2 and Figure 3 The present embodiment provides a battery cell, including a housing 100, an explosion-proof valve 2 and a battery cell, wherein the battery cell is arranged in the housing 100, and the explosion-proof valve 2 is used to open the valve and release the pressure in time when the battery cell is thermally runaway. The housing 100 and the explosion-proof valve 2 can be designed separately and fixedly connected, and the housing 100 and the explosion-proof valve 2 can also be an integral structure formed by integral stamping. The housing 100 and the explosion-proof valve 2 are fixedly connected in a manner including but not limited to welding or fasteners (such as screws or nuts). The housing 100 includes a top cover 1 and an outer shell 20, wherein the outer shell 20 has a receiving groove, and the battery cell is accommodated in the receiving groove. The top cover 1 and the outer shell 20 are connected and the notch of the receiving groove is sealed to protect the battery cell inside the outer shell 20. The top cover 1 usually integrates at least one pole as a positive electrode or a negative electrode, and the top cover 1 preferably integrates a positive pole 11 as a positive pole and a negative pole 12 as a negative pole. Preferably, the explosion-proof valve 2 and the top cover 1 on the housing 100 are fixed separately or integrally stamped. In other embodiments, the explosion-proof valve 2 may be fixed separately from the outer shell 20 on the housing 100 or may be integrally stamped and formed.

[0054] Please also read Figure 3 , Figure 4 and Fig.13 The explosion-proof valve 2 specifically includes a fixing portion 21, a side wall portion 22 and a main body portion 23 which are connected in sequence, wherein the fixing portion 21 is used to be fixedly connected to the top cover 1 or formed integrally with the top cover 1, and the main body portion 23 is arranged to face the exhaust direction to withstand the gas pressure. In the battery field, the main body portion 23 is equivalent to facing the inside of the battery cell. When the battery cell has thermal runaway, the gas pressure will be mainly concentrated on the main body portion 23, and the side wall portion 22 can be relative to the main body portion 23. Figure 3 As shown, the side wall portion 22 extends upward (it can be understood that the side wall portion 22 extends in a direction away from the interior of the battery cell), or the side wall portion 22 can also be relative to the main body portion 23 as shown. Figure 4 As shown, the side wall portion 22 extends downward (it can be understood that the side wall portion 22 extends toward the direction close to the inside of the battery cell), the shape of the side wall portion 22 is a closed annular structure, and at least one wall surface of the inner wall of the side wall portion 22 located inside the battery cell or the outer wall exposed to the outside is provided with a first weak portion 222, the thickness of the first weak portion 222 is relatively thin, and when the first weak portion 222 is subjected to excessive air pressure inside the battery cell, it will break. Among them, the first weak portion 222 can be formed by providing a first groove 221 on the inner wall or outer wall of the side wall portion 22, and the formation method of the first groove 221 includes but is not limited to stamping, chemical corrosion or tool cutting.

[0055] In this embodiment, the fixing portion 21 , the side wall portion 22 and the main body portion 23 are preferably an integrally formed structure.

[0056] Please refer again Figure 3 , Figure 4 and Fig.13 To further explain the above scheme, the pressure relief principle of the explosion-proof valve 2 is: the main body 23 is subjected to air pressure in the vertical Z direction. As long as the pressure on the main body 23 in the vertical Z direction reaches a preset value, regardless of whether the main body 23 is deformed greatly, the first weak portion 222 on the side wall 22 will break immediately to achieve the purpose of pressure relief. In other words, in this solution, by setting the first weak portion 222 on the side wall portion 22, the accuracy of the burst value of the first weak portion 222 will have nothing to do with the degree of deformation of the main body portion 23, that is, even if the main body portion 23 is greatly deformed, it will not have a great impact on the accuracy of the burst value of the first weak portion 222, thereby improving the accuracy of the burst value of the explosion-proof valve 2; and, since the accuracy of the burst value of the first weak portion 222 has nothing to do with the degree of deformation of the main body portion 23, the explosion-proof valve 2 can be made of low-cost Al 3003 or other low-cost aluminum alloys, while achieving that the explosion-proof valve 2 can still have a relatively accurate burst value, while reducing the manufacturing cost of the explosion-proof valve 2, thereby reducing the cost of the battery cell; in particular, when the material of the explosion-proof valve 2 is the same as that of the top cover 1, the explosion-proof valve 2 can be directly obtained by stamping the top cover 1, thereby abandoning the welding process of welding the explosion-proof valve 2 to the top cover 1, so as to further reduce the manufacturing cost of the battery cell, and at the same time, the production efficiency of the battery cell can be greatly improved due to the abandonment of the welding process.

[0057] Please refer again Figure 3 , Figure 4 and Fig.13Furthermore, since the side wall portion 22 is arranged on the side of the main body portion 23 (that is, the side wall portion 22 extends upward or downward relative to the main body portion 23), the force area of ​​the side wall portion 22 subjected to the internal air pressure of the battery cell is small, and since the outer shape of the side wall portion 22 is a closed annular structure, the deformation of the side wall portion 22 is actually very small. The side wall portion 22 with very small deformation will hardly have much impact on the accuracy of the bursting value of the first weak portion 222, thereby ensuring that the explosion-proof valve 2 has a more accurate bursting value. In addition, since the weak portion of the prior art is designed on the main body 23, it is easily burned through by the direct impact of hot gas in a high temperature environment (such as a battery module or battery pack integrating more battery cells), while the first weak portion 222 of the explosion-proof valve 2 of the present solution is hidden on the side wall 22, so the first weak portion 222 is not easily burned through at high temperatures, thereby improving the safety of the battery cells. Moreover, the thickness of the main body 23 of the present solution has nothing to do with the accuracy of the explosion value of the first weak portion 222, so the main body 23 of the present solution can be designed to be thicker to enhance the structural strength of the main body 23 to avoid the main body 23 being burned through at high temperatures, thereby further improving the safety of the battery cells.

[0058] See also Fig.13 , the angle α between the side wall portion 22 and the fixed portion 21 is 60°~150°, α is preferably 75°~135°, and α is more preferably 90°. When α is 90°, the side wall portion 22 extends vertically relative to the fixed portion 21. At this time, when the explosion-proof valve 2 is subjected to the gas pressure inside the battery cell, the deformation of the side wall portion 22 is minimal, that is, the explosion-proof valve 2 has the highest blasting accuracy. In addition, the width W of the notch of the first groove 221 is less than or equal to 3mm, and W is greater than or equal to 0.1mm. If W is too large, the processing difficulty of the first groove 221 is greater, and the side wall portion 22 is prone to breakage during processing. If W is too small, the first weak portion 222 formed on the side wall portion 22 does not have a better blasting effect.

[0059] In this embodiment, the first groove 221 can be an annular structure, so that the outer wall or inner wall of the side wall portion 22 has the first weak portion 222 in one circle, so that the ability of the outer wall or inner wall of the side wall portion 22 to withstand air pressure in the entire circumference is consistent. The first groove 221 can also be designed as a C-shaped structure, so that the first weak portion 222 is C-shaped, that is, when the first weak portion 222 is broken, a small part of the side wall portion 22 is still connected to the fixing portion 21 and the main body 23.

[0060] Please refer again Figure 4 and Fig.13In this embodiment, the side wall portion 22 in the explosion-proof valve 2 is preferably designed to extend downward relative to the main body portion 23, so that the main body portion 23 is actually connected to the top of the side wall portion 22, and the fixing portion 21 is actually connected to the bottom of the side wall portion 22. In other words, the distance from the main body portion 23 to the battery cell is greater than the distance from the fixing portion 21 to the battery cell. In addition, in this embodiment, the fixing portion 21 is preferably designed to extend outward relative to the side wall portion 22. When this explosion-proof valve 2 and the top cover 1 are connected, the side wall portion 22 will tend to deform outward due to the air pressure inside the battery cell. The reason why this scheme preferably adopts the structural design of the explosion-proof valve 2 is that when this explosion-proof valve 2 and the top cover 1 are connected, it is conducive to forming an upwardly open concave groove 3 on the outside of the side wall portion 22. This concave groove 3 can resist the outward deformation of the side wall portion 22, thereby further improving the accuracy of the explosion value of the explosion-proof valve 2. Specifically, a support wall 13 is provided on the top cover 1, and the support wall 13 is designed as the outer side of the side wall 22. The support wall 13 is also preferably an annular structure. When the explosion-proof valve 2 and the top cover 1 are connected, the fixing part 21 is connected to the bottom of the support wall 13, so that the support wall 13, the fixing part 21 and the side wall 22 are jointly formed to form the above-mentioned recessed groove 3. The recessed groove 3 is also preferably an annular structure. When the side wall 22 is subjected to the gas pressure inside the battery cell, the side wall 22 will have a deformation tendency to approach the support wall 13, and the fixing part 21 will have a tendency to deform upward. Since the fixing part 21 is connected to the bottom of the support wall 13, the support wall 13 can suppress the deformation of the side wall 22 in the direction close to the support wall 13 by suppressing the upward deformation of the fixing part 21. Since the deformation degree of the side wall 22 is smaller at this time, the accuracy of the explosion value of the explosion-proof valve 2 can be further improved.

[0061] See also Figure 5 , when the support wall 13 is closer to the side wall portion 22, the width of the concave groove 3 will become narrower, and at this time, the ability of the support wall 13 to suppress the upward deformation of the fixing portion 21 will be stronger, so that the deformation of the side wall portion 22 in the direction close to the support wall 13 can be further suppressed, and the accuracy of the explosion value of the explosion-proof valve 2 can be further improved. When the support wall 13 is extremely close to the side wall portion 22, and when the side wall portion 22 is deformed outward, the support wall 13 can even abut against the deformed side wall portion 22, thereby directly resisting the deformation of the side wall portion 22 outward, and the accuracy of the explosion value of the explosion-proof valve 2 will be higher.

[0062] See also Figure 6 If the pressure relief area requirement is not large, Figure 6As shown, a part of the main body 23, a part of the side wall 22 and a part of the fixing part 21 are welded to the top cover 1 or are integrally formed with the top cover 1, so that the recessed groove 3 extends in an arc shape. At this time, the side wall 22 can also be restrained from deforming outward, thereby achieving the purpose of improving the accuracy of the explosion-proof valve 2.

[0063] In fact, the position on the side wall portion 22 where the deformation toward the outside is the largest is the first weak portion 222. Figures 3 to 6 and Fig.13 As shown, in this embodiment, the first groove 221 is preferably designed to be lower than the opening 31 of the recessed groove 3, that is, the distance from the end surface of the support wall 13 away from the fixing portion 21 to the fixing portion 21 is greater than the distance from the first weak portion 222 to the fixing portion 21, so that the support wall 13 is arranged around the outside of the first weak portion 222. At this time, the first weak portion 222 can be further suppressed from deforming outward, thereby further improving the accuracy of the explosion value of the explosion-proof valve 2.

[0064] See also Figure 7 The battery cell also includes a flame retardant 4 filled in the recessed groove 3, and the flame retardant 4 is in contact with the outer wall of the support wall 13 and the side wall 22 at the same time. Preferably, the top surface of the flame retardant 4 is higher than the height position of the first weak portion 222, thereby inhibiting the first weak portion 222 from deforming toward the outer side of the support wall 13, thereby further improving the accuracy of the explosion of the explosion-proof valve 2. Secondly, the flame retardant 4 can also protect the first weak portion 222, solving the problem that the first weak portion 222 is easily broken by external force. In addition, since the flame retardant 4 has flame retardant properties, the flame retardant 4 will not be burned when thermal runaway occurs in adjacent battery cells, so that the flame retardant 4 can still reliably protect the first weak portion 222 at high temperatures, avoiding the occurrence of chain thermal runaway, thereby greatly improving the safety of the battery module or battery pack. The flame retardant 4 can be a mica sheet, flame retardant foam, silicone rubber or aerogel adhesive, etc.

[0065] Please also read Figure 8 and Fig.13 In this embodiment, the main body 23 of the explosion-proof valve 2 is preferably designed to be lower than the opening 31 of the concave groove 3 (i.e. Fig.13The value of A in the formula is greater than 0), the top surface of the flame retardant 4 is designed to be lower than the opening 31 of the concave groove 3 or flush with the top surface of the top cover 1. At this time, the first groove 221 is lower than the opening 31 of the concave groove 3, so that a flat waterproof and breathable membrane 5 can be laid on the top surface of the top cover 1. The waterproof and breathable membrane 5 has the characteristics of being waterproof but allowing gas to pass freely. The sheet-shaped waterproof and breathable membrane 5 has the advantage of a simple structure. The waterproof and breathable membrane 5 is specifically located above the explosion-proof valve 2 and covers the opening 31 of the concave groove 3, so that when the first weak part 222 breaks, the electrolyte inside the battery cell will not leak out from the concave groove 3. At the same time, it can also prevent external liquid or other impurities from entering the interior of the battery cell from the concave groove 3, so as to improve the safety of the battery cell. In addition, there is a gap between the waterproof and breathable membrane 5 and the main body 23 of the explosion-proof valve 2, so that the explosion-proof valve 2 has space for upward deformation, ensuring that the first weak part 222 can be broken in time under the preset air pressure. In other embodiments, if the flame retardant 4 is higher than the opening 31 of the concave groove 3 or the main body 23 of the explosion-proof valve 2, Figure 3 As shown, the waterproof and breathable membrane 5 is higher than the top surface of the top cover 1 , and the waterproof and breathable membrane 5 can be designed as a convex structure to avoid the flame retardant component 4 or the main body 23 of the explosion-proof valve 2 .

[0066] In this embodiment, the first weak portion 222 is less than or equal to 3 mm away from the main body 23, so that the main body 23 can be lower than the top surface of the top cover 1. Moreover, the first weak portion 222 is greater than or equal to 0.3 mm away from the main body 23. If the distance is less than 0.3 mm, the processing of the first weak portion 222 is more difficult.

[0067] See also Fig. 9 , the explosion-proof valve 2 can also be provided with a second weak portion 212 on the outer wall or inner wall of the fixing portion 21. Preferably, the second weak portion 212 is formed by providing a second groove 211 on the outer wall or inner wall of the fixing portion. The burst value of the second weak portion 212 is designed to be greater than the burst value of the first weak portion 222. By designing the second weak portion 212, when a serious thermal runaway occurs in the battery cell, the first weak portion 222 and the second weak portion 212 can be broken in sequence to increase the pressure relief area of ​​the explosion-proof valve 2, thereby preventing the battery cell from being over-pressurized and exploding. In this solution, it is not recommended to fill the flame retardant 4 in the concave groove 3, because the flame retardant 4 will prevent the second weak portion 212 from breaking.

[0068] Please refer again Figure 8 and Fig.13In this embodiment, the fixing portion 21 on the explosion-proof valve 2 is preferably designed to be integrally formed with the top cover 1, and the first groove 221 of the explosion-proof valve 2 is preferably designed on the inner wall of the side wall 22. It should be noted that in this solution, the outer wall of the side wall 22 is equivalent to the wall surface facing the support wall 13, and the inner wall of the side wall 22 is equivalent to the wall surface facing away from the support wall 13. Specifically, by designing the fixing portion 21 on the explosion-proof valve 2 to be integrally formed with the top cover 1, a welding process can be saved, thereby reducing the manufacturing cost of the battery cell and improving the production efficiency of the battery cell. However, since the position of the first groove 221 is lower than the opening 31 of the concave groove 3, and the width of the concave groove 3 is not large, when the fixing portion 21 on the explosion-proof valve 2 is integrally formed with the top cover 1 and the first groove 221 is designed on the outer wall of the side wall 22, the processing depth of the first groove 221 is difficult to control. When the processing depth error of the first groove 221 is large, it will have a great impact on the accuracy of the burst value of the first weak portion 222. In other words, the present invention, by designing the first groove 221 of the explosion-proof valve 2 on the inner wall of the side wall 22, not only satisfies the purpose of enabling the fixing portion 21 on the explosion-proof valve 2 to be integrally formed with the top cover 1 in a low-cost manner, but also facilitates accurate control of the depth value of the first groove 221, thereby facilitating improvement of the thickness accuracy of the first weak portion 222, and further facilitating improvement of the accuracy of the burst value of the explosion-proof valve 2. Two specific methods for forming the explosion-proof valve are provided below: Please refer to Fig.10 The first method for forming the explosion-proof valve (forming the other parts of the explosion-proof valve 2 first and then forming the first weak part 222) uses the following processing devices:

[0069] The processing device includes a first upper die 61, a first lower die 62 and a forming drive member 7, wherein the forming drive member 7 is a side punch head or a tool that performs a rotating motion, wherein the first upper die 61 specifically includes a first body portion 611 and a first boss 612 that protrudes downward relative to the first body portion 611, and the first lower die 62 specifically includes a second body portion 621 and a second boss 622 that protrudes upward relative to the second body portion 621, the first boss 612 is used to be pressed together with the second body portion 621, and the second boss 622 is used to be pressed together with the first body portion 611, and when the first upper die 61 and the first lower die 62 are pressed together, the first boss 612 is located on the outer side of the second boss 622;

[0070] Specifically, the first method for forming an explosion-proof valve includes the following steps:

[0071] Step S1: The top cover 1 is punched once or multiple times in the vertical direction by using the first upper die 61 and the first lower die 62. During the punching, the first boss 612 and the second body portion 621 jointly clamp the top cover 1, and the second boss 622 and the first body portion 611 jointly clamp the top cover 1, so that the top cover 1 is punched out with the fixing portion 21, the side wall portion 22 and the main body portion 23, and the above-mentioned concave groove 3 is formed on the periphery of the side wall portion 22 under the punching of the first boss 612;

[0072] Step S2: Remove the first lower mold 62, use the molding driver 7 to extend to the bottom of the main body 23 and arrange it adjacent to the side wall 22, use the first boss 612 of the first upper mold 61 as a support, use the molding driver 7 to cut or laterally punch the side wall 22, so that the side of the side wall 22 facing away from the support wall 13 is cut or punched by the molding driver 7 to form a first groove 221, so that a first weak portion 222 is formed on the side wall 22. At this time, the depth of the first groove 221 can be cut or punched by the molding driver 7 to a preset range, so as to improve the accuracy of the explosion value of the explosion-proof valve 2. At this time, the explosion-proof valve 2 is manufactured. After the molding is completed, the first upper mold 61 will move upward, and at the same time, the molding driver 7 will first shrink horizontally to make the molding driver 7 leave the first groove 221, and finally the molding driver 7 will move downward, so that the molded top cover 1 can be easily unloaded without being restricted by the first upper mold 61 and the molding driver 7.

[0073] Step S1 in the first explosion-proof valve forming method described above is described in more detail. When the top cover 1 is originally thin, the top cover 1 can be punched once in the up and down direction to obtain the fixing portion 21, the side wall portion 22, the main body portion 23, and the concave groove 3 located outside the side wall portion 22. When the top cover 1 is originally thick, the top cover 1 can be punched multiple times in the up and down direction to obtain the fixing portion 21, the side wall portion 22, the main body portion 23, and the concave groove 3 located outside the side wall portion 22. For details, please refer to Fig.11 , step S1 may specifically include the following steps:

[0074] Step S11: using the third upper die 81 and the third lower die 82 to stamp the top cover 1 in the up and down directions, so that the thickness of the top cover 1 where the explosion-proof valve 2 is required to be formed becomes thinner, so that a recessed portion 14 is stamped out on the top cover 1;

[0075] Step S12: using the fourth upper die 83 and the fourth lower die 84 to stamp the recessed portion 14 in the up and down directions, so as to preliminarily obtain the fixing portion 21, the side wall portion 22, the main body portion 23 and the recessed groove 3 located at the periphery of the side wall portion 22;

[0076] Step S13: Use the fifth upper mold 85 and the fifth lower mold 86 to stamp the top cover 1 so that the angle of the side wall portion 22 relative to the fixing portion 21 and the angle of the side wall portion 22 relative to the main body portion 23 are both within the set range (for example, 90°±10°). The fifth upper mold 85 here can also be directly used as the above-mentioned first upper mold 61, and the fifth lower mold 86 here can also be directly used as the above-mentioned first lower mold 62.

[0077] For a more detailed description of step S2 in the first explosion-proof valve forming method, please refer to Fig.10 In the figure corresponding to step S2 in , when the positions of the first upper mold 61 and the molding driver 7 are opposite to each other, the first groove 221 can be punched out on the outer wall of the side wall portion 22, so that the first weak portion 222 can also be formed on the side wall portion 22. However, since the position of the first groove 221 is lower than the opening 31 of the recessed groove 3 and the width of the recessed groove 3 is not large, even if the first groove 221 with better depth accuracy can be formed on the outer wall of the side wall portion 22, it is difficult for the molding driver 7 to be demolded upward from the recessed groove 3 after stamping. In other words, when the first groove 221 is designed on the outer wall of the side wall portion 22 and the explosion-proof valve 2 is stamped and formed integrally with the top cover 1, it is difficult to demold the molding driver 7. Therefore, the present scheme designs the first groove 221 on the inner wall of the side wall portion 22, so that the molding driver 7 can achieve the purpose of demolding by a simple method of lateral contraction and downward movement.

[0078] Please refer again Fig.10 When the forming drive member 7 is a side punch head, a first protrusion 71 is protruded from the side wall of the forming drive member 7. When the first upper mold 61 and the forming drive member 7 are pressed together, the first protrusion 71 is located on the inner side of the first boss 612. The first protrusion 71 is used to press the side wall portion 22 together with the first boss 612 of the first upper mold 61, so that the inner wall of the side wall portion 22 can form a first groove 221, and then form a first weak portion 222 on the side wall portion 22.

[0079] See also Fig.12 The second method for forming the explosion-proof valve (forming the first weak portion 222 of the explosion-proof valve 2 first and then forming other parts of the explosion-proof valve 2) uses the following processing devices:

[0080] In addition to the above-mentioned first upper mold 61, first lower mold 62 and forming drive member 7, the processing device also includes a second upper mold 63 and a second lower mold 64, wherein the second lower mold 64 has a second protrusion 641 protruding from one side facing the second upper mold 63. When the second upper mold 63 and the second lower mold 64 are pressed together, the second protrusion 641 and the second upper mold 63 are used to stamp the top cover 1 and form a first groove 221 on the top cover 1, thereby forming a first weak portion 222 on the top cover 1.

[0081] Specifically, the second method for forming an explosion-proof valve includes the following steps:

[0082] Step S1: The top cover 1 is stamped in the up-down direction by using the second upper die 63 and the second lower die 64, so that the first groove 221 is stamped out on the bottom surface of the top cover 1. At this time, the first weak portion 222 is stamped out on the top cover 1. This step can also play a role in reducing the thickness of the area where the explosion-proof valve 2 needs to be formed. At this time, a recessed portion 14 is formed on the top surface of the top cover 1;

[0083] Step S2: The first upper die 61 and the first lower die 62 are used to stamp the recessed portion 14 in the upper and lower directions once or multiple times (the number of stamping times can be determined according to the actual thickness of the plate). During stamping, the first boss 612 and the second body portion 621 clamp the top cover 1 together, and the second boss 622 and the first body portion 611 clamp the top cover 1 together, so that the top cover 1 is stamped out with the fixing portion 21, the side wall portion 22 and the main body portion 23, and the first weak portion 222 is located on the side wall portion 22, and the recessed groove 3 is formed on the periphery of the side wall portion 22 under the stamping of the first boss 612;

[0084] Step S3: remove the first lower mold 62, use the forming drive member 7 to extend to the bottom of the main body 23 and arrange it adjacent to the side wall 22, use the first boss 612 of the first upper mold 61 as a support, and use the forming drive member 7 to cut or laterally punch the side wall 22, so that the depth of the first groove 221 is cut or punched by the forming drive member 7 to a preset range, that is, the thickness of the first weak portion 222 on the side wall 22 is cut or punched to a preset range to ensure that the explosion-proof valve 2 has a more accurate explosion value. At this time, the explosion-proof valve 2 is manufactured. After the molding is completed, the first upper mold 61 moves upward, and at the same time, the molding drive member 7 first contracts laterally to make the molding drive member 7 leave the first groove 221, and finally the molding drive member 7 moves downward, so that the molded top cover 1 can be free from the restrictions of the first upper mold 61 and the molding drive member 7 and can be easily unloaded.

[0085] The second method for forming the explosion-proof valve is described in more detail. Since this method is to form the first groove 221 first and then form other parts of the explosion-proof valve 2, after the other parts of the explosion-proof valve 2 are formed through step S2, the depth value of the first groove 221 formed in step S1 has a large error, so the forming drive member 7 in step S3 is required to calibrate the depth of the first groove 221, so as to ensure that the first weak portion 222 has a more accurate thickness, thereby making the explosion-proof valve 2 have an accurate burst value. For further information, please refer to Fig.12, when the second upper mold 63 and the second lower mold 64 are interchanged in step S1 and the first groove 221 is punched out on the top surface of the top cover 1, the technical solution of arranging the first groove 221 on the outer wall of the side wall portion 22 can be obtained through step S2. This solution correspondingly requires that in step S3, the forming driving member 7 be designed to extend into the recessed groove 3 so that the depth value of the first groove 221 can be calibrated. However, since the position of the first groove 221 is lower than the opening 31 of the recessed groove 3 and the width of the recessed groove 3 is not large, the forming driving member 7 in step S3 is It is difficult to demould upward from the depressed groove 3. In other words, when the first groove 221 is designed on the outer wall of the side wall portion 22 and the explosion-proof valve 2 is stamped integrally with the top cover 1, it is difficult to demould the molding driver 7 after molding. Therefore, the first groove 221 is designed on the inner wall of the side wall portion 22 in this scheme, so that the molding driver 7 can calibrate the depth of the first groove 221 to improve the accuracy of the explosion value of the explosion-proof valve 2. At the same time, the molding driver 7 can also achieve the purpose of demoulding by a simple method of lateral contraction and downward movement.

[0086] Both of the above two forming methods can form the above-mentioned explosion-proof valve 2. Since the original welding process of welding the explosion-proof valve 2 to the top cover 1 is abandoned, the above two forming methods can reduce the manufacturing cost of the top cover 1, and then reduce the manufacturing cost of the battery cell, while also greatly improving the production efficiency of the battery cell.

[0087] Please refer again Fig.13 The two engraved lines 2211 in the above-mentioned first groove 221 respectively form an angle with the center line L of the side wall portion 22 in the circumferential direction, and this angle is within -89°~+89°. Preferably, the angle is between -30°~+30°, wherein 0° represents that the engraved line 2211 is parallel to the center line L, a positive angle represents that the angled opening is biased downward, and a negative angle represents that the angled opening is biased upward. The first groove 221 is a full circle or a half circle or a partitioned arrangement, and the shape of the first groove 221 is a triangle, a trapezoid, a square or other shapes. The first groove 221 can be one or more spaced arrangements. The above-mentioned main body 23 can be straight, arched or concave. When the main body 23 is large in area or thin in thickness, the main body 23 can be provided with reinforcing ribs to suppress deformation.

[0088] Please refer again Fig.13 , the gap B between the side wall portion 22 and the top cover 1 (i.e., the width of the concave groove 3, or understood as the distance between the support wall 13 and the side wall portion 22) satisfies 0≤B≤10mm. When the gap is small, the side wall portion 22 of the explosion-proof valve 2 is close to the support wall 13 of the top cover 1, thereby suppressing the side wall portion 22 from deforming outward and improving the accuracy of the explosion value of the explosion-proof valve 2; when the gap B is large, the ability of the support wall 13 to suppress the side wall portion 22 from deforming outward is slightly weak, but it can be as follows Figure 8 As shown, a flame retardant 4 is filled in the concave groove 3 to inhibit the side wall 22 from deforming outward, thereby improving the accuracy of the explosion value of the explosion-proof valve 2. The thickness C of the side wall 22 of the explosion-proof valve 2 satisfies 0.1≤C≤1.5mm, the residual thickness D≤0.8C of the weakest part in the first weak part 222 of the explosion-proof valve 2, and the residual thickness E of the strongest part in the first weak part 222 of the explosion-proof valve 2 satisfies 1.2D≤E≤1C. By setting it in this way, the side wall 22 of the explosion-proof valve 2 is not easy to deform, and after the explosion-proof valve 2 is opened, part of the side wall 22 is still not broken and connected to the top cover 1. The thickness F of the fixed part 21 of the explosion-proof valve 2 satisfies 0.3≤F≤3mm. If the thickness of the fixed part 21 is too small, it is easy to deform. If the thickness of the fixed part 21 is too large, the gap A between the main body 23 and the top surface of the top cover 1 will become smaller. The thickness G of the main body 23 of the explosion-proof valve 2 is designed to be 0.1≤G≤1.5 mm. If the thickness of the main body 23 is too small, it is easy to deform. If the thickness of the main body 23 is too large, the gap A between the main body 23 and the top surface of the top cover 1 will become smaller.

[0089] The present embodiment also provides a battery, which includes a plurality of the above-mentioned battery cells. The battery can be understood as a battery module or a battery pack. When the battery is understood as a battery module, the battery includes a plurality of battery cells connected in series in sequence. When the battery is understood as a battery pack, in addition to a plurality of battery cells connected in series in sequence, the battery can also include a box, a battery management system, a collection device, a thermal management system, etc., wherein the plurality of battery cells, the battery management system, the collection device, and the thermal management system are all accommodated in the box, and the collection device is respectively connected to the battery management system with the polarity of the plurality of battery cells, so that the battery management system can obtain the temperature, voltage or current information of each battery cell, thereby facilitating the battery management system to control the working state of each battery cell. The battery management system can also control the thermal management system to heat or cool the plurality of battery cells, so that the battery cells can work within a preset temperature range. Since the battery of the present embodiment adopts the above-mentioned explosion-proof valve 2, the battery of the present embodiment also has the advantage of higher safety.

[0090] This embodiment also provides an electric device. Since the electric device of this embodiment adopts the above-mentioned battery, the electric device of this embodiment also has the advantage of higher safety. Especially when the electric device is a new energy vehicle, it can greatly improve the driving safety of the new energy vehicle.

[0091] The above are only preferred embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for the purpose of explaining the principles of the present invention, and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention, and other specific implementation methods of the present invention that can be associated with by technicians in this field without creative labor, should be included in the scope of protection of the present invention.

Claims

1. A battery cell, characterized in that: include: Housing (100); A battery cell, arranged in the housing (100); An explosion-proof valve (2) is formed by stamping at least a portion of the housing (100), the explosion-proof valve comprising a fixing portion (21), a side wall portion (22), and a main body portion (23) which are connected in sequence; The side wall portion (22) is a closed annular structure, at least one wall surface of the inner wall or the outer wall of the side wall portion (22) is provided with a first weak portion (222), and the fixing portion (21) is connected to the housing (100).

2. The battery cell according to claim 1, characterized in that: The housing (100) comprises an outer shell (20) and a top cover (1); a receiving groove is provided in the outer shell (20); the battery cell is received in the receiving groove; the top cover (1) is connected to the outer shell (20) and seals a notch of the receiving groove; the explosion-proof valve (2) is formed by stamping at least a portion of the top cover (1); and the fixing portion (21) is connected to the top cover (1).

3. The battery cell according to claim 1, characterized in that: The inner wall or the outer wall of the side wall portion (22) is provided with a first groove (221), and the first weak portion (222) is formed at a position of the side wall portion (22) corresponding to the first groove (221).

4. The battery cell according to claim 3, characterized in that: The width W of the notch of the first groove (221) is less than or equal to 3 mm, and W is greater than or equal to 0.1 mm.

5. The battery cell according to claim 1, characterized in that: The thickness F of the fixing portion (21) satisfies 0.3≤F≤3 mm, and the thickness G of the main body portion (23) satisfies 0.1≤G≤1.5 mm.

6. The battery cell according to claim 1, characterized in that: The thickness C of the side wall portion (22) satisfies 0.1≤C≤1.5 mm, the thickness D of the weakest portion in the first weak portion (222) satisfies ≤0.8C, and the thickness E of the strongest portion in the first weak portion (222) satisfies 1.2D≤E≤1C.

7. The battery cell according to claim 1, characterized in that: The included angle α between the side wall portion (22) and the fixing portion (21) is 60° to 150°.

8. The battery cell according to claim 1, characterized in that: The distance between the first weak portion (222) and the main body portion (23) is less than or equal to 3 mm and greater than or equal to 0.3 mm.

9. The battery cell according to claim 1, characterized in that: The outer wall or the inner wall of the fixing portion (21) is provided with a second weak portion (212), and the burst value of the second weak portion (212) is greater than the burst value of the first weak portion (222).

10. The battery cell according to claim 9, characterized in that: The inner wall or the outer wall of the fixing portion (21) is provided with a second groove (211), and the fixing portion (21) forms the second weak portion (212) at a position corresponding to the second groove (211).

11. The battery cell according to any one of claims 1 to 10, characterized in that: The distance between the main body (23) and the battery core is greater than the distance between the fixing portion (21) and the battery core.

12. The battery cell according to claim 11, characterized in that: The housing (100) is provided with a support wall (13) on the outside of the side wall portion (22), and the fixing portion (21) is connected to the support wall (13), so that the support wall (13), the fixing portion (21) and the side wall portion (22) are jointly surrounded to form a recessed groove (3).

13. The battery cell according to claim 12, characterized in that: The width of the recessed groove (3) is less than or equal to 10 mm.

14. The battery cell according to claim 12, characterized in that: The distance from the end surface of the support wall (13) away from the fixing portion (21) to the fixing portion (21) is greater than the distance from the first weak portion (222) to the fixing portion (21).

15. The battery cell according to claim 14, characterized in that: The battery cell further comprises a flame retardant (4) filled in the recessed groove (3), the flame retardant (4) abutting against the outer wall of the support wall (13) and the side wall portion (22) at the same time, and the top surface of the flame retardant (4) is higher than the height position of the first weak portion (222).

16. The battery cell according to claim 14, characterized in that: The main body (23) is lower than the opening (31) of the recessed groove (3), and the battery cell further comprises a waterproof and breathable membrane (5) fixed on the shell, the waterproof and breathable membrane (5) is located above the explosion-proof valve (2) and covers the opening (31) opened by the recessed groove (3), and there is a gap between the waterproof and breathable membrane (5) and the main body (23).

17. The battery cell according to claim 14, characterized in that: The first weak portion (222) is formed by providing a first groove (221) on a surface of the side wall portion (22) facing away from the support wall (13).

18. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 17.

19. An electrical device, characterized in that: Comprising the battery of claim 18.

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