Explosion-proof valve, top cover assembly and lithium battery

Abstract

The utility model relates to the technical field of lithium batteries, and discloses an anti-explosion valve, a top cover assembly and a lithium battery. According to the anti-explosion valve provided by the utility model, the first groove part is formed in the end part, deviating from the top cover, of the welding part in the height direction, and the first groove part is in contact with the external air, so that the contact area between the welding part of the anti-explosion valve and the external air can be increased, namely, the heat dissipation area of the welding part can be increased. By means of the arrangement, heat generated in the welding process can be better transmitted to the external environment through the welding part, welding marks are rapidly cooled, then the temperature gradient between the area close to the outside and the area away from the outside in the welding marks is reduced, temperature distribution of the welding marks is optimized, and therefore cracks generated at the welding marks are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery technical field, concretely relates to a kind of explosion-proof valve, top cap assembly and lithium battery. BACKGROUND

[0002] Lithium battery has the advantages of high voltage, large specific energy, stable discharge voltage, good cycle performance, safety performance, long storage and working life, and is one of the latest development directions in the chemical power industry.

[0003] In the conventional scheme, the battery shell of lithium battery includes a shell with an opening and a top cover capped at the opening of the shell. The top cover is provided with a liquid injection hole and an explosion-proof valve. During use, the internal pressure of the lithium battery gradually rises. Since the explosion-proof valve bears the internal pressure of the entire battery shell, when the pressure value reaches the critical value of the pressure relief of the explosion-proof valve, the thinnest (scored) part of the explosion-proof valve cracks, releasing the internal pressure of the lithium battery and preventing the lithium battery from exploding, thereby improving the safety of the lithium battery. During installation, the explosion-proof valve and the aluminum sheet are fixed by welding.

[0004] However, it is found during welding that the heat dissipation area of the welding area is limited, resulting in a high temperature gradient between the temperature near the external area and the temperature away from the external area in the weld mark, which causes cracks in the weld mark after welding. UTILITY MODEL CONTENTS

[0005] Therefore, the utility model provides an explosion-proof valve, a top cover assembly and a lithium battery to solve the problem of limited heat dissipation area of the welding area, which causes cracks in the weld mark after welding.

[0006] In a first aspect, the utility model provides an explosion-proof valve, which includes an explosion-proof part, a welding part and a first groove part. Specifically, the welding part is arranged around the outer side of the circumferential outer edge of the explosion-proof part, and the welding part is used for welding and fixing. The first groove part is opened in the end of the welding part away from the top cover along the height direction, and the first groove part is in contact with the external air.

[0007] Beneficial effects: by opening the first groove part in the end of the welding part away from the top cover along the height direction and contacting the first groove part with the external air, the contact area between the welding part of the explosion-proof valve and the external air can be increased, i.e. the heat dissipation area of the welding part can be increased. By such arrangement, the heat generated during welding can be better transferred to the external environment through the welding part, effectively reducing the temperature of the weld mark, thereby reducing the temperature gradient between the area near the external area and the area away from the external area in the weld mark, optimizing the temperature distribution of the weld mark, and thus reducing the cracks generated in the weld mark.

[0008] In an alternative embodiment, the first groove part is annularly arranged.

[0009] Beneficial effects: since the welding part presents a ring-shaped arrangement, by arranging the first groove part in a ring shape, the first groove part and the welding part are both ring-shaped structures, which can increase the contact area between the welding part of the explosion-proof valve and the external air, thereby further improving the heat dissipation performance of the explosion-proof valve, helping to quickly dissipate the heat generated during welding through the welding part to the external environment, thereby further reducing the temperature gradient at the welding mark.

[0010] In an optional embodiment, the slot width w1 of the first groove part is greater than or equal to the groove bottom width w2.

[0011] Beneficial effects: by making the slot width of the first groove part greater than or equal to the groove bottom width, the air inside the first groove part rises quickly after being heated, thereby quickly circulating with the air outside the environment, avoiding the retention of heated air inside the first groove part and accelerating heat transfer.

[0012] In an optional embodiment, the horizontal distance w3 between the slot inner wall of the first groove part near the outer side wall of the welding part and the outer side wall of the welding part is 0.7-1mm.

[0013] Beneficial effects: by precisely controlling the horizontal distance between the slot inner wall of the first groove part near the outer side wall of the welding part and the outer side wall of the welding part, the phenomenon of large stress concentration in the welding part can be improved, thereby improving the reliability of the explosion-proof valve.

[0014] In an optional embodiment, the thickness t1 of the welding part is greater than or equal to the thickness t2 of the explosion-proof part.

[0015] Beneficial effects: by setting the thickness of the welding part to be greater than or equal to the thickness of the explosion-proof part, the welding part can have higher strength to withstand thermal stress and mechanical stress generated during welding, and provide larger welding area and better heat conduction capacity, so that the heat distribution during welding is uniform, which helps to reduce cracks, deformation and other defects that may occur during welding, thereby improving the welding quality.

[0016] In an optional embodiment, the explosion-proof part is provided with a notch.

[0017] Beneficial effects: by providing the explosion-proof part with a notch, a pre-set thin area is formed on the explosion-proof part, which will preferentially break when the internal pressure of the battery exceeds the set value, ensuring that the explosion-proof valve responds in time when the pressure is too high, releasing the excessive pressure, preventing the battery from causing power supply abnormalities and safety hazards due to excessive pressure, and improving the reliability of the explosion-proof valve.

[0018] In a second aspect, the utility model also provides a top cap assembly, including top cap and the explosion -proof valve of first aspect provides. Specifically, the top cap is equipped with pressure relief port, the explosion -proof valve is installed in the pressure relief port.

[0019] Beneficial effect: by being equipped with pressure relief port on the top cap, and installing the explosion -proof valve, when the internal pressure of battery is abnormally increased and exceeds the preset value, the explosion -proof valve can respond in time and break, open, thereby releasing the pressure that is too high.

[0020] In an alternative embodiment, a second groove portion is formed at the pressure relief port of the top cap, and when the explosion -proof valve is installed at the pressure relief port, the second groove portion is circumferentially arranged at the outer edge of the welding portion.

[0021] Beneficial effect: when the explosion -proof valve is installed at the pressure relief port by welding, by being equipped with the second groove portion that is circumferentially arranged at the outer edge of the welding portion at the pressure relief port of the top cap, it is helpful to optimize the stress distribution acting on the welding portion, reduce the stress degree of the welding portion, thereby improving the ability of the welding portion to resist deformation. At the same time, further increase the heat dissipation area, thereby reducing the temperature gradient between the area close to the outside and the area away from the outside in the welding mark, optimizing the temperature distribution of the welding mark, thereby reducing the cracks generated at the welding mark.

[0022] In an alternative embodiment, the groove depth d of the second groove portion is 0.3-0.7mm; and / or the horizontal distance w4 between the groove inner wall of the second groove portion close to the outer side wall of the welding portion and the side wall of the installation step close to the second groove portion is 0.7-1mm; and / or the slot width w5 of the second groove portion is greater than or equal to the slot bottom width w6.

[0023] In a third aspect, the utility model further provides a lithium battery, which comprises a battery shell, a battery cell and a top cap assembly provided in the second aspect. Specifically, the battery shell is provided with a receiving chamber with one side being open; the battery cell is installed in the receiving chamber; and the top cap assembly is installed at the opening of the receiving chamber to separate the battery cell from the external environment.

[0024] Beneficial effect: by installing the top cap assembly at the opening of the battery shell, the battery cell is effectively separated from the external environment, preventing the battery cell from being affected by external factors such as humidity, dust, pollutants, etc., and ensuring normal operation of the battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application, the drawings needed to be used in the description of the specific embodiments will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0026] Figure 1 The top view of the explosion-proof valve provided by the present application is shown in the figure.

[0027] Figure 2 The Figure 1 The sectional view of the A-A section in the figure.

[0028] Figure 3 The Figure 2 The local enlarged schematic view of the B part in the figure.

[0029] Figure 4 The perspective view of the explosion-proof valve and the top cover in the separated state in the top cover assembly provided by the present application is shown in the figure.

[0030] Figure 5 The Figure 4 The local enlarged schematic view of the C part in the figure.

[0031] Figure 6 The top view of the explosion-proof valve and the top cover in the separated state in the top cover assembly provided by the present application is shown in the figure.

[0032] Figure 7 The Figure 6 The sectional view of the D-D section in the figure.

[0033] Figure 8 The Figure 7 The local enlarged schematic view of the E part in the figure.

[0034] Explanation of the reference signs:

[0035] 1, explosion-proof valve; 11, explosion-proof part; 12, welding part; 13, first groove part; 14, notch;

[0036] 2, top cover; 21, pressure relief port; 22, second groove part; 23, mounting step;

[0037] w1, first groove part slot width; w2, first groove part slot bottom width; w3, horizontal distance between the slot inner wall of the first groove part and the outer side wall of the welding part;

[0038] t1, welding part thickness; t2, explosion-proof part thickness;

[0039] d, second groove depth; w4, horizontal distance between the groove inner wall of the second groove portion and the outer side wall of the welding portion; w5, second groove portion slot width; w6, second groove portion slot bottom width. DETAILED DESCRIPTION

[0040] To make the objects, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0041] In the description of the present application, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0042] The terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0043] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", and "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0045] The following will describe the embodiments of the present application with reference to the drawings. Figures 1 to 8

[0046] According to the embodiments of the present application, in a first aspect, an explosion-proof valve 1 is provided.

[0047] ​As shown in Figures 1 to 3 The explosion-proof valve 1 comprises an explosion-proof part 11, a welding part 12 and a first groove part 13.

[0048] Specifically, the welding part 12 is arranged around the outer side of the circumferential outer edge of the explosion-proof part 11, and the welding part 12 is used for welding and fixing; the first groove part 13 is opened in the height direction at the end of the welding part 12 away from the top cover 2, and the first groove part 13 is in contact with the external air.

[0049] In this way, by opening the first groove part 13 in the height direction at the end of the welding part 12 away from the top cover 2, and contacting the first groove part 13 with the external air, the contact area of the welding part 12 of the explosion-proof valve 1 with the external air can be increased, that is, the heat dissipation area of the welding part 12 can be increased. In this way, the heat generated during the welding process can be better transmitted to the external environment through the welding part 12, the temperature of the welding mark can be quickly reduced, thereby reducing the temperature gradient between the area close to the outside and the area away from the outside in the welding mark, optimizing the temperature distribution of the welding mark, and thereby reducing the cracks generated at the welding mark.

[0050] At the same time, by increasing the heat dissipation area of the welding part 12 of the explosion-proof valve 1, the heat dissipation efficiency can be improved, which helps to reduce the thermal stress generated by the explosion-proof valve 1 in a high-temperature working environment, reduces the risk of material aging and performance degradation caused by overheating, and avoids the phenomenon that the explosion valve has exploded and relieved pressure while the internal pressure of the battery has not reached the specified explosion pressure value.

[0051] In addition, due to the improvement of the heat dissipation efficiency, the temperature at the explosion-proof valve 1 is effectively controlled, thereby reducing the maintenance and replacement frequency of the explosion valve due to overheating.

[0052] It can be explained that in the top view, the shape of the first groove part 13 is not specifically limited.

[0053] In one embodiment, as shown in Figure 1 The first groove part 13 is arranged in a ring shape.

[0054] In this way, since the welding part 12 is arranged in a ring shape, by arranging the first groove part 13 in a ring shape, the first groove part 13 and the welding part 12 are both in a ring structure, which can increase the contact area of the welding part 12 of the explosion-proof valve 1 with the external air, thereby further improving the heat dissipation performance of the explosion-proof valve 1, which helps to quickly dissipate the heat generated during the welding process to the external environment through the welding part 12, thereby further reducing the temperature gradient at the welding mark.

[0055] It can be explained that the slot width of the first groove part 13 is defined as w1, and the slot bottom width of the first groove part 13 is defined as w2.

[0056] In one embodiment, as shown inFigures 1 to 3 and Figure 8 As shown in FIG. 13, the slot width w1 of the first recessed portion 13 is greater than or equal to the slot bottom width w2.

[0057] In this way, by setting the slot width w1 of the first recessed portion 13 to be greater than or equal to the slot bottom width w2, the air inside the first recessed portion 13 can quickly rise after being heated, so as to quickly circulate with the air outside the environment, thereby avoiding the heated air from remaining inside the first recessed portion 13 and accelerating the heat transfer.

[0058] It should be noted that the shape of the first recessed portion 13 inside the explosion-proof portion 11 is not limited in the present application. It can be an arc-shaped slot, a trapezoidal slot, etc. Figure 3

[0059] Preferably, the cross section of the first recessed portion 13 is in a trapezoidal structure as shown in FIG. 14. Figure 3

[0060] Of course, the cross section of the first recessed portion 13 can also be in a rectangular shape. In this case, the inner side wall surface of the first recessed portion 13 is perpendicular to the projection of the slot bottom plane in the vertical reference plane.

[0061] In an embodiment, as shown in FIG. 15 and FIG. 16, the horizontal distance between the slot inner wall of the outer side wall of the first recessed portion 13 close to the welding portion 12 and the outer side wall of the welding portion 12 is defined as w3. Figures 1 to 3 Figure 8 Preferably, w3 is 0.7-1 mm.

[0062] In this way, by accurately controlling the horizontal distance between the slot inner wall of the outer side wall of the first recessed portion 13 close to the welding portion 12 and the outer side wall of the welding portion 12, the phenomenon of greater stress concentration in the welding portion 12 can be improved, thereby improving the reliability of the explosion-proof valve 1.

[0063] It should be noted that the thickness of the welding portion 12 is defined as t1, and the thickness of the explosion-proof portion 11 is defined as t2.

[0064] In an embodiment, as shown in FIG. 17 and FIG. 18, the thickness t1 of the welding portion 12 is greater than or equal to the thickness t2 of the explosion-proof portion 11.

[0065] In this way, by setting the thickness of the welding portion 12 to be greater than or equal to the thickness of the explosion-proof portion 11, the welding portion 12 can have higher strength to withstand the thermal stress and mechanical stress generated during the welding process, and can provide larger welding area and better heat conduction capacity, so that the heat distribution during the welding process is uniform, which helps to reduce the defects such as cracks and deformation that may occur during the welding process, thereby improving the welding quality. Figures 1 to 3 Figure 8

[0066] ​​​​​​

[0067] At the same time, since the thickness of the explosion-proof part 11 is less than or equal to the thickness of the welding part 12, it is ensured that the explosion-proof part 11 can be broken preferentially, so that the external environment is communicated with the inside of the battery, and the excessively high pressure in the inside of the battery is released, thereby further improving the reliability of the explosion-proof valve 1.

[0068] In one embodiment, as shown in Figures 1 to 3 and Figure 8 , the explosion-proof part 11 is provided with a notch 14.

[0069] In this way, by providing the notch 14 on the explosion-proof part 11, a predetermined thin area is formed on the explosion-proof part 11, and when the pressure in the inside of the battery exceeds a set value, the weak area will be broken preferentially, so that the external environment is communicated with the inside of the battery, and it is ensured that the explosion-proof valve 1 responds in time when the pressure is excessively high, thereby releasing the excessively high pressure, preventing the battery from being abnormally powered due to the excessively high pressure, and preventing the battery from having safety hazards and other problems, and improving the reliability of the explosion-proof valve 1.

[0070] It can be explained that in the present application, the position of the notch 14 is not specifically limited. For example, in the height direction, the notch 14 can be arranged at the end of the explosion-proof part 11 in contact with the outside; of course, the notch 14 can also be arranged at the end of the explosion-proof part 11 away from the outside, that is, as shown in Figure 3 , the notch 14 is arranged at the lower end of the explosion-proof part 11.

[0071] It can be explained that in the present application, the cross-sectional shape of the notch 14 is not specifically limited. It can be one or more of arc, triangle, rectangle, trapezoid.

[0072] Preferably, the cross-sectional shape of the notch 14 is arc-shaped, as shown in Figure 3 .

[0073] According to the embodiment of the present application, a second aspect, as shown in Figures 4 to 8 , the utility model also provides a top cover 2 assembly, including top cover 2 and the explosion-proof valve 1 provided by the first aspect.

[0074] Specifically, as shown in Figure 4 and Figure 5 , the top cover 2 is provided with a pressure relief port 21; the explosion-proof valve 1 is installed at the pressure relief port 21.

[0075] In this way, by providing the pressure relief port 21 on the top cover 2 and installing the explosion-proof valve 1, when the pressure in the inside of the battery abnormally rises and exceeds a predetermined value, the explosion-proof valve 1 can respond in time, the notch 14 is broken, thereby opening the pressure relief port 21 and releasing the excessively high pressure.

[0076] It can be explained that in the present application, the way of installing the explosion-proof valve 1 at the pressure relief port 21 is not specifically limited.

[0077] As one of the embodiments, a mounting step 23 is arranged at the pressure relief port 21 in a ring shape, and the mounting step 23 is used to support and mount the welding portion 12 of the explosion-proof valve 1. The mounted explosion-proof valve 1 is located above the mounting step 23.

[0078] Further, a gap is left between the vertical side wall surface of the mounting step 23 close to the second groove portion 22 and the outer wall surface of the welding portion 12 away from the first groove portion 13 to form a ring-shaped filler chamber, which can ensure that the solder can be uniformly and fully filled into the filler chamber during the welding process.

[0079] In one embodiment, the second groove portion 22 is arranged at the pressure relief port 21 of the top cover 2 in a ring shape, and as shown in Figure 5 and Figure 8 , in the horizontal direction, the second groove portion 22 is located on the side of the mounting step 23 away from the pressure relief port 21.

[0080] Preferably, when the explosion-proof valve 1 is mounted at the pressure relief port 21, the second groove portion 22 is arranged around the circumferential outer edge of the welding portion 12.

[0081] In this way, when the explosion-proof valve 1 is mounted at the pressure relief port 21 by welding, the arrangement of the second groove portion 22 around the circumferential outer edge of the welding portion 12 at the pressure relief port 21 of the top cover 2 helps to optimize the stress distribution acting on the welding portion 12, reduce the stress degree of the welding portion 12, and thus improve the ability of the welding portion 12 to resist deformation.

[0082] At the same time, the heat dissipation area is further increased, thereby reducing the temperature gradient between the area close to the outside and the area away from the outside in the weld mark, optimizing the temperature distribution of the weld mark, and thus reducing the cracks generated at the weld mark.

[0083] Further, as shown in Figure 4 and Figure 5 , the second groove portion 22 is arranged around the circumferential outer edge of the mounting step 23.

[0084] It can be explained that in the present application, the specific arrangement position of the second groove is not limited, and it is only required to be arranged close to the welding portion 12.

[0085] In one embodiment, as shown in Figures 4 to 8 , the groove depth d of the second groove portion 22 is 0.3-0.7 mm; and / or the horizontal distance w4 between the notch inner wall of the outer side wall of the second groove portion 22 close to the welding portion 12 and the side wall of the mounting step 23 close to the second groove portion 22 is 0.7-1 mm; and / or the notch width w5 of the second groove portion 22 is greater than or equal to the groove bottom width w6.

[0086] It can be explained that the cross-sectional shape of the second groove portion 22 is not specifically limited in the present application.

[0087] Preferably, the cross-sectional shape of the second groove portion 22 is as shown in Figure 8 a reverse trapezoid, at which time the slot width of the second groove portion 22 is greater than the slot bottom width of the second groove portion 22.

[0088] It can be explained that, before welding, the explosion-proof valve 1 and the top cover 2 are preheated, which can significantly reduce the thermal stress and mechanical stress generated in the welding process, thereby improving the stress concentration phenomenon.

[0089] According to the embodiments of the present application, in a third aspect, the present application further provides a lithium battery, comprising a battery shell, a cell and the top cover assembly provided in the second aspect.

[0090] Specifically, the battery shell is provided with an accommodating cavity with one side being open; the cell is installed in the accommodating cavity; and the top cover assembly is installed at the opening of the accommodating cavity to separate the cell from the external environment.

[0091] In this way, by installing the top cover assembly at the opening of the battery shell, the cell is effectively separated from the external environment, preventing the cell from being affected by external factors such as humidity, dust, pollutants, etc., and ensuring normal operation of the cell.

[0092] Obviously, the above embodiments are only examples for clearly illustrating, and not limit the embodiments. For those skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An explosion relief valve, characterized in that The explosion-proof part (11) comprises: a welding part (12) arranged outside the outer circumferential edge of the explosion-proof part (11), and used for welding fixation; a first groove part (13) arranged on the end of the welding part (12) away from the top cover (2), and in contact with the external air.

2. The explosion-proof valve according to claim 1, wherein the first groove part (13) is arranged in a ring shape.

3. The explosion-proof valve according to claim 1, wherein the slot width w1 of the first groove part (13) is greater than or equal to the groove bottom width w2.

4. The explosion-proof valve according to claim 1, wherein the horizontal distance w3 between the inner wall of the slot of the outer side wall of the welding part (12) and the outer side wall of the welding part (12) is 0.7-1 mm.

5. The explosion-proof valve according to claim 1, wherein the thickness t1 of the welding part (12) is greater than or equal to the thickness t2 of the explosion-proof part (11).

6. The explosion-proof valve according to any one of claims 1-5, wherein the explosion-proof part (11) is provided with a notch (14). The top cover (2) is provided with a pressure relief port (21); 7. A cap assembly characterized by, The explosion-proof valve (1) is the explosion-proof valve (1) according to any one of claims 1-6, and is installed at the pressure relief port (21).

8. The top cover assembly according to claim 7, wherein the pressure relief port (21) of the top cover (2) is provided with a second groove part (22), and when the explosion-proof valve (1) is installed at the pressure relief port (21), the second groove part (22) is arranged outside the circumferential edge of the welding part (12).

9. The top cover assembly according to claim 8, wherein the slot depth d of the second groove part (22) is 0.3-0.7 mm; and / or the horizontal distance w4 between the inner wall of the slot of the outer side wall of the welding part (12) and the side wall of the installation step (23) close to the second groove part (22) is 0.7-1 mm; and / or the slot width w5 of the second groove part (22) is greater than or equal to the groove bottom width w6. The battery shell is provided with an open receiving cavity; The battery cell is installed in the receiving cavity; 10. A lithium battery, characterized by, The top cover assembly is the top cover assembly according to any one of claims 7-9, and is installed at the opening of the receiving cavity to separate the battery cell from the external environment. ​ ​ ​

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