Battery shell, battery monomer and welding method of battery shell and explosion-proof valve

Abstract

The invention belongs to the technical field of batteries, and discloses a battery shell, a battery monomer and a welding method of the battery shell and an anti-explosion valve, the battery shell comprises a reinforcing rib and a plurality of wall bodies, the plurality of wall bodies are sequentially connected end to end to define a containing cavity, at least one of the plurality of wall bodies is a mounting wall, the mounting wall is provided with an anti-explosion hole, and the anti-explosion hole is arranged in the containing cavity. The wall body connected with the mounting wall is an adjacent wall, the edge, connected with the mounting wall, of the adjacent wall extends in the first direction, the reinforcing rib is located in the containing cavity, the two sides of the reinforcing rib are connected with the mounting wall and the adjacent wall respectively, and in the first direction, the reinforcing rib extends from one side of the mounting wall to the other side of the mounting wall. And a powerful guarantee is provided for the sealing performance between the anti-explosion valve and the mounting wall.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery case, a battery cell, and a welding method for the battery case and an explosion-proof valve. Background Art

[0002] Power batteries generally include an internal battery structure and an external battery structure. The internal battery structure mainly includes a pole group, and the external battery structure mainly includes a cover plate and a housing. The housing provides a receiving space for the pole group. The cover plate and the housing are cooperatively welded to form a closed space, thereby forming a complete battery structure.

[0003] When producing the housing, an explosion-proof hole is first punched on the small surface of the housing, and then the explosion-proof valve is welded and sealed at the explosion-proof hole. The structural strength of the area on the small surface of the housing close to the explosion-proof hole is relatively low. When welding the explosion-proof valve, this area is prone to plastic deformation due to heat, and after the welding heat is transferred to the large surface of the housing adjacent to the small surface of the housing, this large surface of the housing will also be deformed by heat, thereby reducing the welding accuracy of the explosion-proof valve and unable to ensure the sealing performance between the explosion-proof valve and the small surface of the housing.

[0004] Therefore, there is an urgent need to propose a battery case, a battery cell, and a welding method for the battery case and an explosion-proof valve to solve the above technical problems. Summary of the Invention

[0005] The first object of the present invention is to provide a battery case, which can improve the welding accuracy of the explosion-proof valve and provide a strong guarantee for the sealing performance between the explosion-proof valve and the installation wall.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A battery case, comprising:

[0008] A plurality of wall bodies, the plurality of wall bodies are sequentially connected end to end to enclose a receiving cavity. At least one of the plurality of wall bodies is an installation wall, an explosion-proof hole is provided on the installation wall, the wall body connected to the installation wall is an adjacent wall, and the edge of the adjacent wall connected to the installation wall extends in a first direction;

[0009] A reinforcing rib, the reinforcing rib is arranged in the receiving cavity, and both sides of the reinforcing rib are respectively connected to the installation wall and the adjacent wall. In the first direction, the reinforcing rib extends from one side of the installation wall to the other side.

[0010] Optionally, the thickness of the reinforcing rib is T1, the thickness of the adjacent wall is T2, and 0.9 ≤ T2 / T1 < 1.4.

[0011] Optionally, the thickness of the reinforcing rib is T1, and T1 ≥ 0.3 mm.

[0012] Optionally, the minimum distance between the hole wall of the explosion-proof hole and the outer wall of the adjacent wall is A, and the distance between the connection position of the reinforcing rib and the adjacent wall and the inner wall of the installation wall is B;

[0013] A / B ≥ 1.73;

[0014] And / or, A / B≤3.6.

[0015] Optionally, a cooling medium circulation gap is formed between the inner wall of the installation wall, the inner wall of the adjacent wall and the reinforcing ribs.

[0016] Optionally, the surface of the reinforcing rib facing away from the cooling medium flow gap is a plane.

[0017] A second object of the present invention is to provide a battery cell having an explosion-proof valve with high welding accuracy and high sealing performance.

[0018] To achieve this object, the present invention adopts the following technical solutions:

[0019] The battery cell comprises a pole group and the above-mentioned battery shell, wherein the pole group is arranged in the accommodating cavity.

[0020] Optionally, the battery cell further includes an explosion-proof valve, a boss is provided on the inner wall of the explosion-proof hole, the boss extends along the circumference of the explosion-proof hole and is connected end to end, and the explosion-proof valve is placed on the side of the boss away from the accommodating cavity and blocks the explosion-proof hole.

[0021] The third object of the present invention is to provide a method for welding a battery shell and an explosion-proof valve, which can reduce the probability of thermoplastic deformation of the wall of the battery shell when welding the explosion-proof valve.

[0022] To achieve this object, the present invention adopts the following technical solutions:

[0023] A method for welding a battery shell and an explosion-proof valve, welding the explosion-proof valve to the battery shell, comprises the following steps:

[0024] A cooling medium circulation gap is formed between the inner wall of the installation wall, the inner wall of the adjacent wall and the reinforcing ribs, and the cooling medium is introduced into the cooling medium circulation gap;

[0025] Weld the edge of the explosion-proof valve to the edge of the explosion-proof hole.

[0026] Optionally, the flow velocity V of the cooling medium is 20 m / s-50 m / s.

[0027] Beneficial effects of the present invention:

[0028] The battery case provided by the present invention includes reinforcing ribs. The reinforcing ribs are arranged in the accommodating cavity, and both sides of the reinforcing ribs are respectively connected to the mounting wall and the adjacent wall. In the first direction, the reinforcing rib extends from one side of the mounting wall to the other side, that is, the reinforcing rib extends from one side of the adjacent wall to the other side in the first direction. Furthermore, the reinforcing rib can support the edge area of the explosion-proof hole (hereinafter referred to as the first easily deformable area) and the area on the adjacent wall close to the explosion-proof hole (hereinafter referred to as the second easily deformable area). Whether punching the explosion-proof hole on the mounting wall or welding the explosion-proof valve at the explosion-proof hole, the probability of deformation of the first easily deformable area and the second easily deformable area is relatively low. Thus, the welding precision of the explosion-proof valve is improved, providing a strong guarantee for the sealing performance between the explosion-proof valve and the mounting wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the first schematic structural view of the battery case provided by the present invention;

[0030] Figure 2 is Figure 1 the partial enlarged view at M in

[0031] Figure 3 is Figure 1 the partial enlarged view at E in

[0032] Figure 4 is the second schematic structural view of the battery case provided by the present invention;

[0033] Figure 5 is Figure 4 the cross-sectional view in the F-F direction in

[0034] Figure 6 is Figure 5 the partial enlarged view at N in

[0035] Figure 7 is the schematic structural view of the battery cell provided by the present invention.

[0036] In the figure:

[0037] D1, the first direction; D2, the second direction; D3, the third direction;

[0038] 1, battery case; 2, cover plate;

[0039] 100, wall body; 110, mounting wall; 111, explosion-proof hole; 112, first easily deformable area; 113, boss; 120, adjacent wall; 121, second easily deformable area; 200, accommodating cavity; 300, reinforcing rib; 400, cooling medium flow gap; 500, explosion-proof valve. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only the parts related to the present invention rather than all the structures are shown in the drawings.

[0041] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature can include the direct contact between the first and second features, or can also include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0043] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0044] This embodiment provides a battery case, which can improve the welding accuracy of the explosion-proof valve and provide a strong guarantee for the sealing performance between the explosion-proof valve and the installation wall.

[0045] Specifically, as Figures 1 to 6As shown, the battery case 1 includes reinforcing ribs 300 and a plurality of wall bodies 100. Among them, the plurality of wall bodies 100 are sequentially connected end to end to enclose a receiving cavity 200. At least one of the plurality of wall bodies 100 is an installation wall 110. An explosion-proof hole 111 is provided on the installation wall 110. The wall body 100 connected to the installation wall 110 is an adjacent wall 120. And the edge of the adjacent wall 120 connected to the installation wall 110 extends along the first direction D1. The reinforcing ribs 300 are arranged in the receiving cavity 200, and both sides of the reinforcing ribs 300 are respectively connected to the installation wall 110 and the adjacent wall 120. In the first direction D1, the reinforcing ribs 300 extend from one side of the installation wall 110 to the other side.

[0046] Based on the above design, the reinforcing ribs 300 are arranged in the receiving cavity 200, and both sides of the reinforcing ribs 300 are respectively connected to the installation wall 110 and the adjacent wall 120. In the first direction D1, the reinforcing ribs 300 extend from one side of the installation wall 110 to the other side, that is, the reinforcing ribs 300 extend from one side of the adjacent wall 120 to the other side in the first direction D1. Furthermore, the reinforcing ribs 300 can support the edge area of the explosion-proof hole 111 (hereinafter referred to as the first easily deformable area 112) and the area adjacent to the explosion-proof hole 111 on the adjacent wall 120 (hereinafter referred to as the second easily deformable area 121). Whether the explosion-proof hole 111 is punched on the installation wall 110 or the explosion-proof valve 500 is welded at the explosion-proof hole 111, the probability of deformation of the first easily deformable area 112 and the second easily deformable area 121 is relatively low. Furthermore, the effect of improving the welding accuracy of the explosion-proof valve 500 is achieved, which provides a strong guarantee for the sealing performance between the explosion-proof valve 500 and the installation wall 110.

[0047] In this embodiment, the battery case 1 is generally rectangular in structure (i.e., it has a total of four wall bodies 100), the number of mounting walls 110 is one, and the number of adjacent walls 120 is two. The two adjacent walls 120 are both connected to the same mounting wall 110, and the two adjacent walls 120 are oppositely arranged in the second direction D2. Therefore, the number of reinforcing ribs 300 is two, and each reinforcing rib 300 is respectively connected to an adjacent wall 120. Therefore, when stamping the explosion-proof hole 111 on the mounting wall 110 and welding the explosion-proof valve 500 at the explosion-proof hole 111, the probability of deformation of the first easily deformable areas 112 on both sides of the mounting wall 110 in the second direction D2 is relatively low. Of course, in other embodiments, the number of mounting walls 110 can also be two or three, etc. For example, two mounting walls 110 are oppositely arranged in the third direction D3, and two adjacent walls 120 are oppositely arranged in the second direction D2. At this time, the battery case 1 is generally rectangular in structure; or, among the three mounting walls 110, every two adjacent mounting walls 110 are connected by an adjacent wall 120. At this time, the battery case 1 is generally pentagonal prism-shaped (i.e., it has a total of five wall bodies 100). Other examples of the number of mounting walls 110 and adjacent walls 120 and other shapes of the battery case 1 are not elaborated here. As long as there is a reinforcing rib 300 supported between the mounting wall 110 and the adjacent wall 120. The above first direction D1, second direction D2, and third direction D3 are perpendicular to each other in pairs.

[0048] Optionally, a cooling medium flow gap 400 is formed between the inner wall of the mounting wall 110, the inner wall of the adjacent wall 120, and the reinforcing rib 300. When welding the explosion-proof valve 500, cooling liquid or cooling gas can be introduced into the cooling medium flow gap 400 to absorb the welding heat, further preventing the first easily deformable area 112 and the second easily deformable area 121 from deforming. And in this embodiment, the end faces at both ends of the mounting wall 110, the adjacent wall 120, and the reinforcing rib 300 in the first direction D1 are flush, which is beneficial to simplifying the operation of introducing the cooling medium into the cooling medium flow gap 400, achieving the effects of reducing the production difficulty and improving the production efficiency. In this embodiment, air is introduced into the cooling medium flow gap 400. Of course, in other embodiments, cooling water, etc. can also be introduced into the cooling medium flow gap 400.

[0049] Optionally, the surface of the reinforcing rib 300 facing away from the cooling medium flow gap 400 is a flat surface. When machining the battery case 1, the roughness of the inner surface of the battery case 1 needs to be considered to avoid scratching the electrode group on the inner wall of the battery case 1. In this embodiment, the surface of the reinforcing rib 300 facing away from the cooling medium flow gap 400 (i.e., the surface of the reinforcing rib 300 facing the electrode group) is designed as a flat surface, which is beneficial to reducing the extrusion forming difficulty of the battery case 1 and enabling the battery case 1 to meet the extrusion quality requirements. Usually, in order to avoid the problem of stress concentration at the connection of the two walls of the battery case 1, the edges of the connection of the two walls are usually rounded. Therefore, if the reinforcing rib 300 is not provided between the mounting wall 110 and the adjacent wall 120, the inner wall of the rounded edge needs to be polished, or the battery case 1 is made by a special extrusion forming process to reduce the roughness of the inner wall surface of the rounded edge. In this embodiment, the reinforcing rib 300 is provided between the mounting wall 110 and the adjacent wall 120. Therefore, there is no need to consider the roughness problem of the inner wall of the rounded edge between the mounting wall 110 and the adjacent wall 120. As long as the surface of the reinforcing rib 300 facing the electrode group is a flat surface, the surface of the reinforcing rib 300 facing the electrode group can have a low roughness through a conventional extrusion forming process, which has the effect of reducing the production difficulty of the battery case 1.

[0050] Optionally, the thickness of the reinforcing rib 300 is T1, T1≥0.3mm. Exemplarily, T1 can be 0.3mm, 0.35mm, 0.4mm or 0.5mm, etc. Among them, it is preferably T1≥0.35 to ensure that the reinforcing rib 300 has sufficient structural strength to support the adjacent wall 120 and the mounting wall 110.

[0051] Optionally, the thickness of the adjacent wall 120 is T2, 0.9≤T2 / T1<1.4. For example, T2 / T1 can be 0.9, 1.1, 1.2 or 1.36, etc., so that the adjacent wall 120 itself can have a certain structural strength. On this basis, the reinforcing rib 300 also has a certain structural strength and can play a reliable supporting role for the adjacent wall 120. Specifically, if T2 / T1<0.9, the thickness of the adjacent wall 120 is too small, reducing the structural strength of the adjacent wall 120 itself; if T2 / T1≥1.4, the thickness of the reinforcing rib 300 is too small, reducing the structural strength of the reinforcing rib 300 and making the reinforcing rib 300 unable to play a reliable supporting role for the adjacent wall 120; and if the thickness of the reinforcing rib 300 is too small, the structural strength of the reinforcing rib 300 is too small. When the battery case 1 is prepared by the extrusion process, wrinkles are likely to appear on the surface of the reinforcing rib 300, which will increase the roughness of the surface of the reinforcing rib 300 facing the electrode group (i.e., the surface of the reinforcing rib 300 facing away from the cooling medium flow gap 400), which is not conducive to improving the extrusion quality of the battery case 1.

[0052] Optionally, the minimum distance between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is A, and the distance between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is B. A / B ≥ 1.73. For example, A / B can be 1.73, 2.15, 3.41, etc. If A / B < 1.73, then B is too large, which will cause the reinforcing rib 300 to occupy too much space in the accommodation cavity 200, which is not conducive to improving the utilization rate of the internal space of the battery case 1, and thus not conducive to improving the energy density of the battery cell.

[0053] It should be noted that in this embodiment, a boss 113 is provided on the hole wall of the explosion-proof hole 111. The boss 113 extends along the circumference of the explosion-proof hole 111 and is connected end to end. The explosion-proof valve 500 is placed on the side of the boss 113 away from the accommodation cavity 200 and seals the explosion-proof hole 111. Therefore, the above-mentioned A refers to the minimum distance between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120, and the size of the boss 113 protruding from the hole wall of the explosion-proof hole 111 has nothing to do with A.

[0054] Optionally, A / B ≤ 3.6. For example, A / B can be 3.6, 2.75, 1.83, etc. If A / B > 3.6, then B is too small. If B is too small, it will reduce the supporting force of the reinforcing rib 300 on the adjacent wall 120 and the mounting wall 110, and thus increase the probability of deformation problems in the first easily deformable area 112 and the second easily deformable area 121. Moreover, if B is too small, the structural strength of the connection area between the reinforcing rib 300 and the adjacent wall 120 will be reduced. When the battery case 1 is prepared by the extrusion process, wrinkles are likely to appear in the connection area between the reinforcing rib 300 and the adjacent wall 120, which will increase the surface roughness of the side of the reinforcing rib 300 facing the electrode group (i.e., the side of the reinforcing rib 300 away from the cooling medium flow gap 400), which is not conducive to improving the extrusion quality of the battery case 1.

[0055] Optionally, B ≥ 1.2 mm. Exemplarily, B can be 1.2 mm, 1.25 mm, 1.3 mm, 1.45 mm, etc. Among them, it is better that B ≥ 1.25 mm to ensure that the reinforcing rib 300 has sufficient supporting ability for the adjacent wall 120 and the mounting wall 110.

[0056]

[0057] Table 1 provides six groups of examples and six groups of comparative examples. The material of the battery case 1 in the six groups of examples and six groups of comparative examples is imported aluminum alloy MXF2, the material of the reinforcing rib 300 is copper material, the size of the explosion-proof valve 500 is 60 mm × 15 mm, and the cooling medium introduced into the cooling medium flow gap 400 during welding of the explosion-proof valve 500 is dry air.

[0058] In Example 1, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.35 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 3.33. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0059] In Example 2, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.5 mm, the thickness T1 of the reinforcing rib 300 is 0.45 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.11, A / B is 3. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0060] In Example 3, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 2.6 mm, the thickness T1 of the reinforcing rib 300 is 0.55 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 0.91, A / B is 1.73. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0061] In Example 4, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.25 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 3.6. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0062] In Example 5, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.5 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 3. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0063] In Example 6, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 2 mm, the thickness T1 of the reinforcing rib 300 is 0.37 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.35, A / B is 2.25. After welding the explosion-proof valve 500 to the mounting wall 110, no out-of-tolerance deformation occurs in the adjacent wall 120 (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is < 1, meeting the extrusion quality requirements. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, and the qualification rate is greater than 98%.

[0064] In Comparative Example 1, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.3 mm, the thickness T1 of the reinforcing rib 300 is 0.35 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.43, A / B is 3.46. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 has out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is greater than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is >1, which does not meet the extrusion quality. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, but the qualified rate is less than 98%.

[0065] In Comparative Example 2, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.2 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 3.75. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 has out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is greater than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is >1, which does not meet the extrusion quality. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, but the qualified rate is less than 98%.

[0066] In Comparative Example 3, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 2.7 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 1.67. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 does not have out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is <1, which meets the extrusion quality. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, but the reinforcing rib 300 occupies a large space, reducing the internal space utilization rate of the battery case 1 and being unfavorable for improving the energy density of the battery cell.

[0067] In Comparative Example 4, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.15 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 3.91. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 has out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is greater than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is >1, which does not meet the extrusion quality. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, but the qualified rate is less than 98%.

[0068] In Comparative Example 5, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 2.8 mm, the thickness T1 of the reinforcing rib 300 is 0.4 mm, the thickness T2 of the adjacent wall 120 is 0.5 mm, T2 / T1 is 1.25, A / B is 1.61. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 does not have out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is less than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is <1, which meets the extrusion quality. The helium leak detection of the explosion-proof valve 500 (i.e., the sealing detection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery case 1 both meet the requirements, but the reinforcing rib 300 occupies a large space, reducing the utilization rate of the internal space of the battery case 1 and being not conducive to improving the energy density of the battery cell.

[0069] In Comparative Example 6, the flow rate V of the cooling medium is 30 m / s, the minimum distance A between the hole wall of the explosion-proof hole 111 and the outer wall of the adjacent wall 120 is 4.5 mm, the distance B between the connection position of the reinforcing rib 300 and the adjacent wall 120 and the inner wall of the mounting wall 110 is 1.5 mm, the thickness T1 of the reinforcing rib 300 is 0.5 mm, the thickness T2 of the adjacent wall 120 is 0.4 mm, T2 / T1 is 0.8, A / B is 3. After welding the explosion-proof valve 500 to the mounting wall 110, the adjacent wall 120 has out-of-tolerance deformation (i.e., the concave deformation amount of the adjacent wall 120 is greater than 0.4 mm), the surface roughness Ra of each inner wall surface of the battery case 1 (including the reinforcing rib 300) is >1, which does not meet the extrusion quality. The appearance yield rate of the battery case 1 and the qualified rate of the battery case 1 are both less than 98%.

[0070] In summary, when 0.9≤T2 / T1<1.4, 1.73≤A / B≤3.6, T1≥0.35mm, B≥1.25mm, and V ranges from 30m / s to 40m / s, after the explosion-proof valve 500 is welded to the mounting wall 110, the adjacent wall 120 does not have excessive deformation (that is, the concave deformation of the adjacent wall 120 is less than 0.4mm), and the roughness Ra of each inner wall surface (including the reinforcing rib 300) of the battery shell 1 is less than 1, which meets the extrusion quality. The helium inspection of the explosion-proof valve 500 (that is, the sealing inspection between the explosion-proof valve 500 and the mounting wall 110) and the appearance of the battery shell 1 meet the requirements, and the qualified rate is greater than 98%.

[0071] This embodiment also provides a battery cell, such as Figure 7 As shown, the battery cell includes a pole group (not shown in the figure), a cover plate 2 and the above-mentioned battery shell 1, the cover plate 2 is sealed at the opening of the battery shell 1 so that the accommodating cavity 200 forms a closed cavity, and the pole group is arranged in the accommodating cavity 200. The battery cell adopts the above-mentioned battery shell 1, and the welding precision of the explosion-proof valve 500 is high, and it has high sealing performance.

[0072] Compared with setting the explosion-proof valve 500 on the cover plate 2 at the end of the battery shell 1, in the present embodiment, the explosion-proof valve 500 is set on the battery shell 1. When the explosion-proof valve 500 bursts open to exhaust gas, the path for the gas in the battery shell 1 to flow to the explosion-proof valve 500 is shorter, which is conducive to the rapid discharge of the high-pressure gas in the battery shell 1, and has the effect of improving the safety of the battery cell.

[0073] Furthermore, if Figure 6 and Figure 7 As shown, the battery cell also includes an explosion-proof valve 500, and a boss 113 is provided on the inner wall of the explosion-proof hole 111, and the boss 113 extends along the circumference of the explosion-proof hole 111 and is connected end to end. The explosion-proof valve 500 is placed on the side of the boss 113 away from the accommodating chamber 200 and is blocked in the explosion-proof hole 111. In actual production, the explosion-proof valve 500 is first placed on the side of the boss 113 away from the accommodating chamber 200, and then the edge of the explosion-proof valve 500 and the edge of the explosion-proof hole 111 are welded. The design of the boss 113 provides a support for the explosion-proof valve 500, which can not only improve the stability of the connection between the explosion-proof valve 500 and the mounting wall 1110, but also play a positioning effect on the explosion-proof valve 500 when assembling the explosion-proof valve 500 and the battery shell 1, which is conducive to reducing production difficulty and improving production efficiency.

[0074] This embodiment also provides a welding method for a battery shell 1 and an explosion-proof valve 500, which is used to weld the explosion-proof valve 500 to the above-mentioned battery shell 1, and can reduce the probability of thermoplastic deformation of the wall 100 of the battery shell 1 when welding the explosion-proof valve 500.

[0075] Specifically, the method includes the following steps:

[0076] A cooling medium flow gap 400 is formed between the inner wall of the installation wall 110, the inner wall of the adjacent wall 120, and the reinforcing rib 300, and a cooling medium is introduced into the cooling medium flow gap 400;

[0077] Weld the edge of the explosion-proof valve 500 and the edge of the explosion-proof hole 111.

[0078] The cooling medium flowing in the cooling medium flow gap 400 can absorb the welding heat, achieving the effect of rapid heat dissipation, reducing the probability of thermal deformation of the first easily deformable area 112 and the second easily deformable area 121, and thus achieving the effects of improving the welding accuracy of the explosion-proof valve 500 and improving the sealing performance between the explosion-proof valve 500 and the installation wall 110.

[0079] It should be noted that in actual application, the cooling medium can be introduced into the cooling medium flow gap 400 first, and then the explosion-proof valve 500 and the installation wall 110 are welded; or the explosion-proof valve 500 and the installation wall 110 can be welded first, and when the temperature of the first easily deformable area 112 and / or the second easily deformable area 121 rises to a certain temperature value, the cooling medium is introduced into the cooling medium flow gap 400; it can also be that the operation of introducing the cooling medium into the cooling medium flow gap 400 and the operation of welding the explosion-proof valve 500 are carried out simultaneously, which can be determined according to the actual production requirements.

[0080] In this embodiment, the cooling medium introduced into the cooling medium flow gap 400 is air. In actual application, a blower or other air supply equipment can be used to introduce air into the cooling medium flow gap 400, and there is no need to consider discharging the air in the cooling medium flow gap 400 after welding. It can be seen that using air as the cooling medium has the effects of reducing the production difficulty and improving the production efficiency. Of course, in other implementation schemes, cooling water or other cooling media can also be introduced into the cooling medium flow gap 400.

[0081] Furthermore, the flow rate V of the cooling medium is 20 m / s - 50 m / s. Exemplarily, V can be 20 m / s, 30 m / s, 35 m / s, 40 m / s, or 50 m / s, etc. Among them, it is better when V is 30 m / s - 40 m / s to ensure that the cooling medium has a relatively high flow rate to achieve the effect of rapid cooling. At the same time, the flow rate of the cooling medium should not be too fast. For example, if V is greater than 50 m / s, the problem of the battery case 1 shaking is likely to occur, which will affect the welding of the explosion-proof valve 500 and reduce the welding accuracy of the explosion-proof valve 500.

[0082] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. Battery case, characterized in that, Comprising: A plurality of wall bodies (100), the plurality of wall bodies (100) are sequentially connected end to end to enclose a receiving cavity (200), at least one of the plurality of wall bodies (100) is an installation wall (110), an explosion-proof hole (111) is provided on the installation wall (110), the wall body (100) connected to the installation wall (110) is an adjacent wall (120), and the edge of the adjacent wall (120) connected to the installation wall (110) extends along a first direction (D1); Reinforcing ribs (300), the reinforcing ribs (300) are arranged in the receiving cavity (200), and both sides of the reinforcing ribs (300) are respectively connected to the installation wall (110) and the adjacent wall (120), in the first direction (D1), the reinforcing ribs (300) extend from one side of the installation wall (110) to the other side.

2. The battery case according to claim 1, characterized in that, The thickness of the reinforcing rib (300) is T1, the thickness of the adjacent wall (120) is T2, and 0.9 ≤ T2 / T1 < 1.

4.

3. The battery case according to claim 1, characterized in that, The thickness of the reinforcing rib (300) is T1, and T1 ≥ 0.3 mm.

4. The battery case according to claim 1, characterized in that, The minimum distance between the hole wall of the explosion-proof hole (111) and the outer wall of the adjacent wall (120) is A, and the distance between the connection position of the reinforcing rib (300) and the adjacent wall (120) and the inner wall of the installation wall (110) is B; A / B ≥ 1.73; And / or, A / B ≤ 3.

6.

5. The battery case according to claim 1, characterized in that, A cooling medium circulation gap (400) is formed among the inner wall of the installation wall (110), the inner wall of the adjacent wall (120), and the reinforcing rib (300).

6. The battery case according to claim 5, characterized in that, The surface of the reinforcing rib (300) facing away from the cooling medium circulation gap (400) is a plane.

7. Battery cell, characterized in that, Comprising a pole group and the battery case (1) according to any one of claims 1-6, and the pole group is arranged in the receiving cavity (200).

8. The battery cell according to claim 7, wherein The battery cell further includes an explosion-proof valve (500), a boss (113) is provided on the inner wall of the explosion-proof hole (111), the boss (113) extends along the circumference of the explosion-proof hole (111) and is connected end to end, and the explosion-proof valve (500) is placed on the side of the boss (113) facing away from the receiving cavity (200) and blocks the explosion-proof hole (111).

9. The welding method of a battery case and an explosion-proof valve, characterized in that, Welding the explosion-proof valve (500) to the battery case (1) according to any one of claims 1-6 includes the following steps: A cooling medium circulation gap (400) is formed among the inner wall of the installation wall (110), the inner wall of the adjacent wall (120), and the reinforcing rib (300), and a cooling medium is introduced into the cooling medium circulation gap (400); Welding the edge of the explosion-proof valve (500) and the edge of the explosion-proof hole (111).

10. The welding method of the battery case and the explosion-proof valve according to claim 9, characterized in that, The flow velocity V of the cooling medium is 20 m / s - 50 m / s.

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