Shell with anti-explosion valve and power battery

Abstract

The utility model provides a shell with an anti-explosion valve and a power battery. A housing having an explosion-proof valve includes a housing body having an opening. A part of the outer surface of the shell body is recessed inwards by a certain depth to form a nick. The nick is defined by the first side wall, the bottom wall and the second side wall. The bottom wall is far away from the outer surface, the first side wall and the second side wall are located on the two sides of the bottom wall and separated from each other, and the first side wall and the second side wall are asymmetric along the center axis of the bottom wall. Through the structural arrangement, the first side wall and the second side wall do not move synchronously under the action force of thermal expansion and cold contraction caused by charging and discharging of the battery and the internal and external pressure difference, so that the stress difference of the first side wall and the second side wall is weakened, the risk of early breakage is reduced, and the service life of the anti-explosion valve is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, in particular to a secondary battery, and more particularly to a housing with an explosion-proof valve and a power battery. Background Art

[0002] In modern society, more and more driving power sources of electric tools and new energy vehicles are developing towards high capacity and high safety. Batteries are widely used in electric tools and new energy vehicles due to their excellent characteristics such as high capacity. With the rapid development of electric vehicles, people not only pursue high capacity but also pay more attention to the safety of batteries.

[0003] In order to pursue high capacity of power batteries, most commercially available power batteries currently use high-voltage cathode materials. The use of high-voltage cathode materials will lead to instability at the battery-electrolyte interface, and the structure of the 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. Currently, due to the gas generation problem of power batteries, an explosion-proof valve is provided on the battery, especially on the top cover. When the internal pressure of the battery reaches the set value of the explosion-proof valve, the explosion-proof valve bursts to release pressure to prevent the battery from exploding.

[0004] Most current explosion-proof valves are welded to the top cover sheet through a connecting part, and the explosion-proof valve is provided with a notch. However, when the internal pressure of the battery is relatively large, stress concentration will occur on the explosion-proof valve. This stress concentration acts on the notch, and the explosion-proof valve ruptures from the notch to release pressure. The notch is usually formed by die stamping and is in a circular ring structure. During the normal use of the battery, due to 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 the battery, it will cause the explosion-proof valve to show small fluctuating movements up and down. This movement will act on the inner wall and outer wall of the notch in the circular ring structure. Since the inner wall is close to the explosion-proof valve and the outer wall is close to the connecting part welded to the top cover sheet, under the influence of the small fluctuating movement of the explosion-proof valve, the stress difference between the inner wall and the outer wall will be aggravated, so it is easy to cause the notch to rupture in advance before reaching the preset value, thus affecting the use of the explosion-proof valve. Summary of the Utility Model

[0005] Based on the above problems, the utility model provides a housing with an explosion-proof valve and a power battery. Using this explosion-proof valve can reduce the influence of thermal expansion and contraction and pressure difference on the stability of the notch, thereby extending the service life of the explosion-proof valve.

[0006] To achieve the above object, on the one hand, the present utility model provides a housing with an explosion-proof valve, which includes a housing body having an opening. A part of the outer surface of the housing body is recessed inward by a certain depth to form a notch. The notch is surrounded by a first side wall, a bottom wall, and a second side wall. The bottom wall is away from the outer surface. The first side wall and the second side wall are located on both sides of the bottom wall and are separated from each other. The first side wall and the second side wall are asymmetric along the central axis of the bottom wall.

[0007] In the technical solution adopted by the present utility model, a notch is directly formed on the outer surface of the housing body, and the first side wall and the second side wall on both sides of the bottom wall of the notch are asymmetric along the central axis of the bottom wall. Therefore, when subjected to the forces of thermal expansion and contraction during battery charging and discharging and the internal and external pressure difference, the movements of the first side wall and the second side wall are not synchronous, thereby weakening the force difference between the first side wall and the second side wall, reducing the risk of premature rupture, and extending the service life of the explosion-proof valve.

[0008] As a technical solution of the present utility model, the housing body includes a housing peripheral wall and a housing bottom wall connected to each other. A part of the outer surface of the housing bottom wall is recessed inward by a certain depth to form the notch.

[0009] As a technical solution of the present utility model, one end of the notch is close to the housing peripheral wall.

[0010] As a technical solution of the present utility model, the bottom wall is arc-shaped, the first side wall and the second side wall are both slope-shaped, and the slopes of the first side wall and the second side wall are different.

[0011] As a technical solution of the present utility model, the notch is a circular ring structure, the first side wall is the inner wall of the circular ring structure, and the second side wall is the outer wall of the circular ring structure.

[0012] As a technical solution of the present utility model, the slope of the second side wall is greater than the slope of the first side wall.

[0013] As a technical solution of the present utility model, the certain depth is 0.5 mm to 0.8 mm, and the certain depth accounts for 70% to 90% of the thickness of the housing body.

[0014] As a technical solution of the present utility model, the radian of the bottom wall is 0.15 to 0.40, and the slopes of the first side wall and the second side wall are independently 15° to 45°.

[0015] On the other hand, 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 housing is the aforementioned housing with an explosion-proof valve. Description of the Drawings

[0016] Figure 1 The front view of the power battery according to an embodiment of the present utility model.

[0017] Figure 2 The bottom view of the housing with an explosion-proof valve according to an embodiment of the present utility model.

[0018] Figure 3 The sectional view of the housing with an explosion-proof valve according to an embodiment of the present utility model.

[0019] Figure 4 is Figure 3 The enlarged view of the circled part in

[0020] Figure 5 is Figure 4 The enlarged view of the part indicated by A in

[0021] Explanation of component symbols

[0022] 100 - Power battery; 10 - Housing body; 11 - Housing peripheral wall; 13 - Housing bottom wall; 30 - Top cover; 31 - First pole; 33 - Second pole; 50 - Notch; 51 - First side wall; 53 - Bottom wall; 55 - Second side wall; A1 - Slope of the first side wall; A2 - Slope of the second side wall Detailed implementation manners

[0023] To better illustrate the purpose, technical solution and beneficial effects of the present utility model, the present utility model will be further described below with reference to the accompanying drawings. It should be noted that the following description of the accompanying drawings is a further explanation of the present utility model and should not be construed as a limitation on the protection scope of the present utility model. It should be noted that usually the power battery is placed vertically, and the end of the pole on the top cover of the power battery that extends out for connection with the outside is the upper side, that is, the top, and the opposite end is the lower side, that is, the bottom.

[0024] As Figures 1 to 3 shown, the power battery 100 of the present utility model includes a housing (not shown in the figure), an electric core (not shown in the figure) accommodated in the housing, and a top cover 30 for sealing the housing.

[0025] The housing includes a housing body 10 having an opening. The housing body 10 includes a connected housing peripheral wall 11 and a housing bottom wall 13. The housing peripheral wall 11 and the housing bottom wall 13 may be an integral structure, that is, formed by stretching a plate. The housing peripheral wall 11 and the housing bottom wall 13 may also be fixed by welding or bonding. The housing peripheral wall 11 and the housing bottom wall 13 enclose a cavity with an opening, and the electric core is accommodated in the cavity. The housing may be, but is not limited to, made of stainless steel, aluminum, carbon steel, magnesium alloy, etc., and may also be an insulating material such as ceramics.

[0026] The battery cell can be of a stacked structure or a wound structure. If it is wound, the battery cell includes a wound body formed by sequentially laminating and then winding a first electrode plate, a separator, and a second electrode plate. If it is stacked, the battery cell is a combination of multiple stacked bodies formed by sequentially laminating a first electrode plate, a separator, and a second electrode plate, preferably a wound structure. The battery cell can be a round battery cell, or a flat battery cell, a square battery cell, or other special-shaped structures. Of course, the shape of the housing needs to be similar to and match the shape of the battery cell, and it can also be a round structure, a square structure, or other special-shaped structures.

[0027] The top cover 30 and the housing can be fixed by welding, bonding, or fitting after assembling the battery cell. The top cover 30 is provided with a first pole column 31, a second pole column 33, and a liquid injection hole (not shown in the figure). The first pole column 31 and the second pole column 33 are electrically connected to the first electrode plate and the second electrode plate in the battery cell respectively.

[0028] Another example Figures 3 to 5 As shown, a part of the outer surface of the housing body 10 is recessed inward by a certain depth to form a notch 50. Further, as Figure 3 shown, a part of the outer surface of the bottom wall 13 of the housing is recessed inward by a certain depth to form a notch 50. The setting of the notch 50 is equivalent to integrally forming an explosion-proof valve on the bottom wall 13 of the housing, and the internal area surrounded by the notch 50 is the explosion-proof valve. The notch 50 is surrounded by a first side wall 51, a bottom wall 53, and a second side wall 55. The bottom wall 53 is away from the outer surface. The first side wall 51 and the second side wall 55 are located on both sides of the bottom wall 53 and are separated from each other. The first side wall 51 and the second side wall 55 are asymmetric along the central axis of the bottom wall 53. Due to the setting of the notch 50, the bottom wall 53 is thinner to the inner surface of the bottom wall 13 of the housing, constituting a weak stress area. When the internal air pressure of the battery is large and reaches a preset value, the notch 50 ruptures to achieve explosion. In the present utility model, the notch 50 is directly formed on the outer surface of the housing body 10, and the first side wall 51 and the second side wall 55 on both sides of the bottom wall 53 of the notch 50 are asymmetric along the central axis of the bottom wall 53. Therefore, when subjected to the forces of thermal expansion and contraction and the internal and external pressure difference during battery charging and discharging, the movements of the first side wall 51 and the second side wall 55 are not synchronized, thereby weakening the stress difference between the first side wall 51 and the second side wall 55, reducing the risk of premature rupture, and prolonging the service life of the explosion-proof valve.

[0029] Furthermore, a notch 50 is directly formed on the outer surface of the housing body 10, that is, the notch 50 and the housing bottom wall 13 are of an integral structure. When preparing the housing, the housing peripheral wall 11, the housing bottom wall 13 and the notch 50 can be obtained by stretching or stamping a sheet. One end of the notch 50 is close to the housing peripheral wall 11, so the notch 50 is not located at the exact center of the housing. If the battery cell is a wound battery cell, gas will first accumulate at the exact center of the housing, and the air pressure there is higher than other areas inside the housing. If the notch 50 is provided at the exact center of the housing, it will burst in advance when reaching the preset value. Therefore, setting the notch 50 close to the housing peripheral wall 11 can improve the accuracy of bursting.

[0030] The bottom wall 53 of the notch 50 is arc-shaped, and the radian of the bottom wall 53 is 0.15 - 0.40. Both the first side wall 51 and the second side wall 55 are ramp-shaped, and the slopes of the first side wall 51 and the second side wall 55 are different. The notch 50 is a circular ring structure, the first side wall 51 is the inner wall of the circular ring structure, and the second side wall 55 is the outer wall of the circular ring structure. The slope of the second side wall 55 is greater than that of the first side wall 51. The slopes of the first side wall 51 and the second side wall 55 are independently 15° - 45°. Since the slope of the second side wall 55 is greater than that of the first side wall 51, the first side wall 51 has greater strength, which just compensates for the greater force that the thermal expansion and contraction during battery charging and discharging and the internal and external pressure difference will exert on the first side wall 51. Therefore, the force difference between the first side wall and the second side wall can be weakened.

[0031] As a supplement, a certain depth is 0.5 mm - 0.8 mm, and the certain depth accounts for 70% - 90% of the thickness of the housing body 10.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than 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 only to 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. A housing with an explosion-proof valve, characterized in that, It includes a housing body with an opening. A part of the outer surface of the housing body is recessed inward by a certain depth to form a notch. The notch is surrounded by a first side wall, a bottom wall, and a second side wall. The bottom wall is away from the outer surface. The first side wall and the second side wall are located on both sides of the bottom wall and are spaced apart from each other. The first side wall and the second side wall are asymmetric along the central axis of the bottom wall.

2. The housing with an explosion-proof valve according to claim 1, characterized in that, The housing body includes a connected housing peripheral wall and a housing bottom wall. A part of the outer surface of the housing bottom wall is recessed inward by a certain depth to form the notch.

3. The housing with an explosion-proof valve according to claim 2, characterized in that, One end of the notch is close to the housing peripheral wall.

4. The housing with an explosion-proof valve according to claim 1, characterized in that, The bottom wall is arc-shaped, and both the first side wall and the second side wall are ramp-shaped, and the slopes of the first side wall and the second side wall are different.

5. The housing with an explosion-proof valve according to claim 4, characterized in that, The notch is a circular ring structure. The first side wall is the inner wall of the circular ring structure, and the second side wall is the outer wall of the circular ring structure.

6. The housing with an explosion-proof valve according to claim 5, characterized in that, The slope of the second side wall is greater than the slope of the first side wall.

7. The housing with an explosion-proof valve according to claim 4, characterized in that, The radian of the bottom wall is 0.15 - 0.40, and the slopes of the first side wall and the second side wall are each independently 15° - 45°.

8. The housing with an explosion-proof valve according to claim 1, characterized in that, The certain depth is 0.5 mm - 0.8 mm, and the certain depth accounts for 70% - 90% of the thickness of the housing body.

9. A power battery, comprising a housing, an electric core accommodated in the housing, and a top cover sealing the housing, characterized in that The housing is the housing with an explosion-proof valve according to any one of claims 1 - 8.

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