Explosion-proof device, shell and power battery

Abstract

The utility model provides an explosion-proof device, a shell and a power battery. The explosion-proof device is a sheet-shaped base body and comprises a connecting part, a buffering part and an explosion part which are connected in sequence. The blasting part is provided with a nick, is parallel to the connecting part and is suspended above the lower surface of the connecting part through the buffer part; according to the explosion-proof device disclosed by the utility model, the explosion part is arranged above the connecting part, so that compared with the traditional arrangement that the connecting part and the explosion part are positioned on the same plane, the stress influence on the explosion part caused by thermal expansion and cold contraction of the battery during charging and discharging and the internal and external pressure difference can be greatly weakened, and the micro-fluctuation form of the explosion-proof device can be more uniform. In addition, the buffer part can play a role in buffering mechanical impact such as external impact and extrusion. Therefore, according to the explosion-proof device, the service life of the explosion-proof device can be prolonged through the arrangement of the buffer part and the explosion part.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, in particular to an explosion-proof device, a shell and a power battery. Background Art

[0002] At present, power batteries are widely used in electric tools and new energy vehicles due to their excellent characteristics such as high capacity and high output. With the rapid development of electric tools and new energy vehicles, people not only pursue high capacity and high output but also pay more attention to the safety of power batteries.

[0003] As is well known, most power batteries use high-voltage ternary cathode materials to meet the high-capacity requirements of power batteries. The use of high-voltage cathode materials will cause instability at the battery-electrolyte interface, and the structure of the ternary cathode material itself is unstable, both of which will cause side reactions in the electrolyte to generate gas. Moreover, overcharging and over-discharging at high voltages will cause a large amount of gas to be generated inside the battery.

[0004] At present, based on such gas generation problems, the industry mostly installs explosion-proof devices on the top cover or shell of the battery. The explosion-proof valve of the explosion-proof device is welded to the top cover sheet or the shell, and there are engraved marks on the explosion-proof valve. When the internal pressure of the battery reaches the set value of the explosion-proof device, stress concentration will occur on the explosion-proof valve, and this stress concentration acts on the engraved marks, causing rupture from the engraved marks to release pressure, thereby achieving the purpose of explosion protection.

[0005] During the normal use of power batteries, the thermal expansion and contraction caused by charging and discharging, or the pressure on the explosion-proof valve from the inside out and from the outside in during the liquid injection and vacuum pumping process of power batteries, will cause the explosion-proof valve to show slight fluctuating movements up and down. This movement will reduce the strength at the engraved marks of the explosion-proof valve, thereby affecting the service life of the explosion-proof valve. Although there are currently reinforcing ribs on the explosion-proof valve to buffer the stress concentration at the engraved marks, so that the slight fluctuating form of the explosion-proof valve is more uniform, thereby extending the service life of the explosion-proof valve. However, the manufacturing process and usage conditions of power batteries are complex, and the external stress and internal pressure generated are also complex. A single form of reinforcing rib cannot better meet the more complex use of power batteries. In addition, vehicle-mounted power batteries are often affected by mechanical impacts such as impacts and squeezes during use, and there is a risk of damaging the explosion-proof valve. Summary of the Utility Model

[0006] Based on the above problems, the utility model provides an explosion-proof device, a shell and a power battery. Using this explosion-proof device can reduce the influence of thermal expansion and contraction and pressure difference on explosion-proof stability, and can also play a role in mechanical buffering against the outside world, thereby extending the service life of the explosion-proof device.

[0007] To achieve the above object, on the one hand, the present utility model provides an explosion-proof device, which is a sheet-like substrate, including a connecting part, a buffer part and an explosion part connected in sequence. The explosion part has a notch and is arranged parallel to the connecting part, and the explosion part is suspended above the lower surface of the connecting part by means of the buffer part.

[0008] In the technical solution adopted by the present utility model, the explosion-proof device includes a connecting part, a buffer part and an explosion part connected in sequence, and the explosion part with a notch is arranged parallel to the connecting part and is suspended above the lower surface of the connecting part by means of the buffer part. In other words, the explosion-proof device of the present utility model places the explosion part above the connecting part. Compared with the traditional setting where the connecting part and the explosion part are on the same plane, it can greatly weaken the stress influence on the explosion part due to the thermal expansion and contraction and the internal and external pressure difference during the charging and discharging of the battery, and can make the micro-fluctuation form of the explosion-proof device more uniform. In addition, the setting of the buffer part can play a buffering role for external mechanical impacts such as impacts and squeezes. Therefore, the explosion-proof device of the present utility model can extend the service life of the explosion-proof device through the settings of the buffer part and the explosion part.

[0009] As a technical solution of the present utility model, the buffer part includes a first wall and a second wall that are parallel to each other, and a bending part is arranged between the first wall and the second wall.

[0010] As a technical solution of the present utility model, both the first wall and the second wall are perpendicular to the connecting part, the first wall is connected to the connecting part, the second wall is connected to the explosion part, and the height dimension of the first wall is greater than the height dimension of the second wall.

[0011] As a technical solution of the present utility model, the bending part is arc-shaped.

[0012] As a technical solution of the present utility model, the distance between the first wall and the second wall is 1 - 5 mm.

[0013] As a technical solution of the present utility model, the lower surface of the explosion part is flush with or higher than the upper surface of the connecting part, and the distance between the explosion part and the connecting part is 0 - 2 mm.

[0014] As a technical solution of the present utility model, the connecting part is a ring structure and the inner ring is connected to the first wall.

[0015] As a technical solution of the present utility model, the explosion part is connected to the second wall, and a notch is formed by the edge of the explosion part close to the second wall being recessed downward.

[0016] The second aspect of the present utility model provides a housing, which includes a housing body and the aforementioned explosion-proof device provided on the housing body. The housing body and the connecting portion are of an integrally formed structure or a split structure, and the blasting portion protrudes outwardly from the housing body.

[0017] The third aspect of the present utility model provides a power battery, which includes a housing, an electric core accommodated in the housing, and a top cover for sealing the housing. The top cover includes a top cover sheet, a pole column, and an explosion-proof device. The explosion-proof device is the aforementioned explosion-proof device. The top cover sheet and the connecting portion are of an integrally formed structure or a split structure, and the blasting portion protrudes outwardly from the top cover. Description of the Drawings

[0018] Figure 1 It is the front view of the power battery according to an embodiment of the present utility model.

[0019] Figure 2 It is the bottom view of the housing according to an embodiment of the present utility model.

[0020] Figure 3 It is the cross-sectional view of the housing according to an embodiment of the present utility model.

[0021] Figure 4 It is the front view of the top cover according to another embodiment of the present utility model.

[0022] Figure 5 It is the cross-sectional view of the top cover according to another embodiment of the present utility model.

[0023] Figure 6 The three-dimensional view of the explosion-proof device of the present utility model in the first direction.

[0024] Figure 7 The three-dimensional view of the explosion-proof device of the present utility model in the second direction.

[0025] Figure 8 The bottom view of the explosion-proof device of the present utility model.

[0026] Figure 9 It is Figure 8 the cross-sectional three-dimensional view in the A-A direction.

[0027] Figure 10 It is Figure 8 the cross-sectional view in the A-A direction.

[0028] Figure 11 It is Figure 10 a variation diagram of

[0029] Figure 12 It is Figure 3 the enlarged view of the circled part in

[0030] Description of the Component Symbols

[0031] 100 - Power battery; 10 - Housing body; 11 - Peripheral part of the housing, 13 - Bottom of the housing; 30 - Top cover sheet; 31 - First pole; 33 - Second pole; 35 - Seal; 50 - Explosion-proof device; 51 - Connecting part; 53 - Buffer part; 531 - First wall; 533 - Bending part; 535 - Second wall; 55 - Blasting part; 57 - Notch; d1 - Distance between the first wall and the second wall; d2 - Distance between the blasting part and the connecting part Detailed implementation mode

[0032] To better illustrate the purpose, technical solution and beneficial effects of the present invention, the present invention will be further described below with reference to the accompanying drawings. It should be noted that the following description of the drawings is a further explanation of the present invention and should not be construed as a limitation on the protection scope of the present invention. It should be noted that usually the power battery is placed vertically, the end of the pole of the power battery top cover extending out for external connection is the upper side, that is, the top, and the opposite end is the lower side, that is, the bottom.

[0033] As Figure 1 shown, the power battery 100 of the present invention includes a housing, an electric core accommodated in the housing, and a top cover for sealing the housing.

[0034] The housing includes a housing body 10 having an opening. The housing body 10 includes a connected peripheral part 11 of the housing and a bottom 13 of the housing. The peripheral part 11 of the housing and the bottom 13 of the housing can be an integral structure, that is, formed by stretching a sheet. The peripheral part 11 of the housing and the bottom 13 of the housing can also be fixed by welding or bonding. The peripheral part 11 of the housing and the bottom 13 of the housing enclose a cavity with an opening, and the electric core is accommodated in the cavity. The housing can be, but is not limited to, made of stainless steel, aluminum, carbon steel, magnesium alloy, etc., and it can also be an insulating material such as ceramics.

[0035] The electric core can be a stacked structure or a wound structure. If it is wound, the electric core includes a wound body formed by sequentially laminating and winding a first pole piece, an isolation film and a second pole piece. If it is stacked, the electric core is a combination of multiple laminates formed by sequentially laminating a first pole piece, an isolation film and a second pole piece, and preferably a wound structure. The electric core can be a circular electric core, or a flat electric core, a square electric core or other special-shaped structures. Of course, the shape of the housing needs to be similar to the shape of the electric core to match it, and it can also be a circular structure, a square structure or other special-shaped structures.

[0036] The top cover and the housing can be fixed by welding, bonding or fitting after assembling the battery cells. The top cover includes a top cover sheet 30, pole columns and a liquid injection hole 70. The pole columns include a first pole column 31 and a second pole column 33. At least one of the first pole column 31 and the second pole column 33 is insulated from the top cover sheet 30 and sealed by a seal 35. The first pole column 31 and the second pole column 33 are respectively electrically connected to the first electrode plate and the second electrode plate in the battery cell.

[0037] An explosion-proof device 50 can be provided on the housing or the top cover of the present utility model. As Figures 2 - 3 shown, the explosion-proof device 50 is provided on the bottom 13 of the housing. The bottom 13 of the housing and the explosion-proof device 50 can be of an integral structure or a split structure. If the bottom 13 of the housing and the explosion-proof device 50 are of an integral structure, they can be formed by processes such as stamping and extrusion. If the bottom 13 of the housing and the explosion-proof device 50 are of a split structure, they can be formed by welding or bonding. Preferably, the explosion-proof device 50 and the bottom 13 of the housing are of an integral structure. When preparing the housing, the circumferential part 11, the bottom 13 of the housing and the explosion-proof device 50 can be obtained by stretching the sheet material. The central axis of the explosion-proof device 50 coincides with the central axis of the housing body 10. The explosion-proof device 50 is arranged at the center of the housing. If the battery cell is a wound battery cell, the explosion-proof device 50 can be placed at the center of the wound battery cell. Since there is usually a certain gap in the middle of the wound battery cell, the space utilization rate can be improved. Or as Figures 4 - 5 shown, the explosion-proof device 50 is provided on the top cover sheet 30. The top cover sheet 30 and the explosion-proof device 50 can be of an integral structure or a split structure. If the top cover sheet 30 and the explosion-proof device 50 are of an integral structure, they can be formed by processes such as stamping and extrusion. If the top cover sheet 30 and the explosion-proof device 50 are of a split structure, they can be formed by welding or bonding.

[0038] As Figures 6 - 11 shown, the explosion-proof device 50 has a sheet-like substrate. The sheet-like substrate is usually an aluminum sheet. The explosion-proof device 50 includes a connecting part 51, a buffer part 53 and a blasting part 55 which are connected in sequence. The blasting part 55 has a notch 57 and is arranged parallel to the connecting part 51. The blasting part 55 is suspended above the lower surface of the connecting part 51 by means of the buffer part 53. In the explosion-proof device 50, placing the blasting part 55 above the connecting part 51 can greatly weaken the stress influence on the blasting part due to the thermal expansion and contraction and the internal and external pressure difference during battery charging and discharging compared with the traditional setting where the connecting part 51 and the blasting part 55 are in the same plane, and can make the micro-fluctuation form of the explosion-proof device 50 more uniform. In addition, the setting of the buffer part 53 can play a buffering role for external mechanical impacts such as impacts and squeezes. Therefore, the service life of the explosion-proof device 50 can be extended through the settings of the buffer part 53 and the blasting part 55.

[0039] Further as Figures 10 - 12As shown, the buffer portion 53 includes a first wall 531 and a second wall 535 that are parallel to each other. A bending portion 533 is provided between the first wall 531 and the second wall 535. Both the first wall 531 and the second wall 535 are perpendicular to the connecting portion 51. The first wall 531 is connected to the connecting portion 51, and the second wall 535 is connected to the blasting portion 55. The height dimension of the first wall 531 is greater than the height dimension of the second wall 535. The buffer portion 53 is arc-shaped, equivalent to a U-shaped structure with a certain height difference and asymmetry on both sides. The distance d1 between the first wall 531 and the second wall 535 is 1 to 5 mm. Therefore, the buffer portion 53 has a certain buffer space in the horizontal direction. If the explosion-proof device 100 is subjected to an external mechanical impact, the buffer portion 53 can play a certain buffering role to protect the explosion-proof device 100.

[0040] In addition, the connecting portion 51 is a ring-shaped structure, and its inner circle is connected to the first wall 531. The outer circle of the connecting portion 51 and the housing body 10 or the top cover piece 30 are of an integral structure or a split structure. If it is an integral structure, the connecting portion 51, the buffer portion 53, and the blasting portion 55 are formed by processes such as stamping and extrusion of the housing body 10 or the top cover piece 30. In actual operation, a one-step method or multi-step stamping and extrusion can be used. If it is a split structure, the connecting portion 51 is welded or bonded to the mounting holes of the housing body 10 and the top cover piece 30. After installation and fixation, the buffer portion 53 plays a "grafting" role, and the blasting portion 55 can be convexly provided outside the housing body 10 or the top cover piece 30 (that is, at least one outer surface of the blasting portion 55 protrudes from the outer surface of the housing body 10 or the top cover piece 30). Therefore, the influence of the stress of the thermal expansion and contraction and the internal and external pressure difference of the battery during charging and discharging on the stability of the explosion-proof valve can be greatly reduced.

[0041] Furthermore, the blasting portion 55 is connected to the second wall 535, and a notch 57 is formed by the edge of the blasting portion 55 near the second wall 535 being recessed downward. Further as Figure 12 shown, the lower surface of the blasting portion 55 is flush with or higher than the upper surface of the connecting portion 51. The distance between the blasting portion 55 and the connecting portion 51 is 0 to 2 mm. The distance between the two should not be too large to avoid occupying too much space and affecting the volume energy density.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it is not limited to only the embodiments listed. Those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An explosion-proof device, which is a sheet-shaped substrate, comprising a connecting portion, a buffer portion and a bursting portion connected in sequence, characterized in that: The bursting part has a notch and is arranged parallel to the connecting part. The bursting part is suspended above the lower surface of the connecting part by the buffer part.

2. The explosion-proof device according to claim 1, characterized in that: The buffer portion includes a first wall and a second wall that are parallel to each other, and a bent portion is provided between the first wall and the second wall.

3. The explosion-proof device according to claim 2, characterized in that: The first wall and the second wall are both perpendicular to the connecting portion, the first wall is connected to the connecting portion, the second wall is connected to the bursting portion, and the height dimension of the first wall is greater than the height dimension of the second wall.

4. The explosion-proof device according to claim 2, characterized in that: The bent portion is arc-shaped.

5. The explosion-proof device according to claim 2, characterized in that: The distance between the first wall and the second wall is 1-5 mm.

6. The explosion-proof device according to claim 1, characterized in that: The lower surface of the bursting part is flush with or higher than the upper surface of the connecting part, and the distance between the bursting part and the connecting part is 0-2 mm.

7. The explosion-proof device according to claim 2, characterized in that: The connecting portion is an annular structure and the inner ring is connected to the first wall.

8. The explosion-proof device according to claim 2, characterized in that: The bursting portion is connected to the second wall, and the edge of the bursting portion close to the second wall is recessed downward to form the notch.

9. A housing, characterized in that: The invention comprises a shell body and an explosion-proof device as claimed in any one of claims 1 to 8 arranged on the shell body, wherein the shell body and the connecting part are an integrally formed structure or a split structure, and the bursting part is protrudingly arranged on the shell body.

10. A power battery, comprising a shell, a battery cell contained in the shell and a top cover sealing the shell, wherein the top cover comprises a top cover sheet, a pole and an explosion-proof device, characterized in that: The explosion-proof device is the explosion-proof device according to any one of claims 1 to 8, the top cover sheet and the connecting portion are an integrally formed structure or a split structure, and the bursting portion is protrudingly disposed on the top cover.

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