Battery casing, battery and battery module

Abstract

The present invention belongs to the technical field of batteries, and discloses a battery shell, a battery and a battery module. The battery shell includes a shell body, and the shell body includes two opposite butt joints. The two butt joints are welded to form a weld structure, so that the shell body forms an open hollow shell structure, and the butt joint includes a bright band, and the width dimension of the bright band along the first direction is W, and the wall thickness dimension of the shell body is T, and 0.3≤W / T≤0.8 is satisfied. By limiting the width dimension W of the bright band along the first direction and the wall thickness dimension T of the shell body, so that both satisfy 0.3≤W / T≤0.8, it is ensured that the bright band of the butt joint occupies a sufficient area, so that during welding, the flat and smooth butt joint surface can effectively improve the quality of the welding of the two butt joint surfaces, thereby improving the structural strength and pressure bearing capacity of the battery shell weld structure, avoiding leakage of the battery shell weld structure under internal pressure, and improving the sealing.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery casing, a battery and a battery module. Background Art

[0002] The battery casing has the functions of insulation, sealing, current conduction, pressure relief and fuse protection. The current conduction is achieved by welding the poles on the battery casing to the pole ears of the battery cell pole group, thereby realizing the current conduction function. The insulation function is achieved by arranging plastic parts outside the poles to avoid contact between the poles and the casing, thereby realizing the insulation function.

[0003] The battery casing is usually made of raw material plates through bending, rolling, welding and cutting processes. When the battery is used in a long-term cycle of charge and discharge, high-temperature and high-pressure gas will be generated inside. At this time, the welding joints of the battery casing will be subjected to the pressure brought by the high-temperature and high-pressure gas, and the surface of the raw material plates used to form the battery casing is relatively rough at the joints, resulting in low structural strength and poor pressure bearing capacity at the welding joints of the battery casing formed after welding. It is easy to leak under the pressure of the high-temperature and high-pressure gas and has poor sealing. Summary of the invention

[0004] The object of the present invention is to provide a battery housing, a battery and a battery module, which have high structural strength, strong pressure bearing capacity, are not prone to leakage under the pressure of high-temperature and high-pressure gas, and have good sealing performance.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] On the one hand, a battery shell is provided, the battery shell comprising a shell body, the shell body comprising two opposite butt joint surfaces, the two opposite butt joint surfaces being welded to form a weld structure, so that the shell body forms a hollow shell structure with an open opening;

[0007] The butt joint surface comprises a bright band, the width dimension of the bright band along the first direction is W, the wall thickness dimension of the shell body is T, and the condition 0.3≤W / T≤0.8 is satisfied.

[0008] Optionally, the weld structure includes a first boss, the first boss protrudes toward one side of the shell body along the first direction, the length dimension of the first boss along the second direction is L1, and satisfies 1.4T≤L1≤2T.

[0009] Optionally, the weld structure includes a second boss, the second boss protrudes toward the other side of the shell body along the first direction, the length dimension of the second boss along the second direction is L2, and satisfies T≤L2≤1.8T.

[0010] Optionally, a length dimension L2 of the second boss is smaller than a length dimension L1 of the first boss.

[0011] Optionally, a height dimension of the first boss protruding along the first direction is h1, a height dimension of the second boss protruding along the first direction is h2, and 1≤h1 / h2≤4 is satisfied.

[0012] Optionally, a protective fillet is provided on a side of the first boss facing away from the second boss;

[0013] And / or, the protective fillet is provided on a side of the second boss facing away from the first boss.

[0014] Optionally, the two butting surfaces are spliced ​​by high-frequency welding.

[0015] Optionally, the bursting pressure of the shell body is P, P≥1.2Mpa, and the wall thickness dimension T of the shell body satisfies, 0.3mm≤T≤2mm.

[0016] On the other hand, a battery is also provided, comprising a battery casing as described in any one of the above items, and further comprising a pole group and a battery cover, wherein the battery cover is arranged on the opening of the battery casing to form a closed accommodating cavity, and the pole group is accommodated in the accommodating cavity.

[0017] On the other hand, a battery module is also provided, the battery module comprising at least two batteries as described above.

[0018] Beneficial effects of the present invention:

[0019] The present invention provides a battery shell, which includes a shell body formed by splicing two butt joint surfaces. By limiting the width dimension W of a bright band of a butt joint surface on the shell body along a first direction and the wall thickness dimension T of the shell body, the width dimension W of the bright band of the butt joint surface along the first direction and the wall thickness dimension T of the shell body satisfy 0.3≤W / T≤0.8, ensuring that the bright band of the butt joint surface occupies a sufficient area, so that when the two butt joint surfaces are welded, the flat and smooth butt joint surface can effectively improve the quality of the welding of the two butt joint surfaces, thereby improving the structural strength and pressure bearing capacity of the battery shell weld structure, avoiding leakage of the battery shell weld structure under the pressure of high-temperature and high-pressure gas, and improving the sealing.

[0020] The present invention also provides a battery, which has a higher pressure-bearing capacity by applying the above-mentioned battery casing, thereby preventing the battery from being scrapped after a short period of use due to leakage caused by high-temperature and high-pressure gas exerting pressure on the weld structure, thereby extending the service life of the battery and the product quality.

[0021] The present invention also provides a battery module, which, by applying the above-mentioned battery, avoids the situation in which, when the battery is in thermal runaway, the high-temperature and high-pressure gas is not discharged along the set position, but leaks at the weld structure of the battery shell, causing influence on the normal operation of other batteries, thereby improving the overall protection and safety of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a cross-sectional stereoscopic display diagram of the docking surface on the battery housing provided by the present invention;

[0023] Figure 2 It is a cross-sectional plane diagram showing the docking surface on the battery housing provided by the present invention;

[0024] Figure 3 It is a structural schematic diagram of the upper shell body of the battery shell provided by the present invention;

[0025] Figure 4 It is a partial structural cross-sectional view of the weld structure on the battery housing provided by the present invention;

[0026] Figure 5 It is a metallographic diagram of a battery casing provided by the present invention when the breaking position is not at the weld structure during a tensile test;

[0027] Figure 6 It is a metallographic diagram of a battery casing provided by the present invention when the breaking position is located at the weld structure during a tensile test.

[0028] In the figure:

[0029] 1. Shell body; 11. Butt joint surface; 111. Bright band; 112. Fillet band; 113. Shear band; 114. Kneading band; 12. Welding seam structure; 121. First boss; 122. Second boss; 123. Protective fillet. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0034] The battery casing has the functions of insulation, sealing, current conduction, pressure relief and fuse protection. The current conduction is achieved by welding the poles on the battery casing to the pole ears of the battery cell pole group, thereby realizing the current conduction function. The insulation function is achieved by arranging plastic parts outside the poles to avoid contact between the poles and the casing, thereby realizing the insulation function.

[0035] The battery casing is usually made of raw material plates through bending, rolling, welding and cutting processes. When the battery is used in a long-term cycle of charge and discharge, high-temperature and high-pressure gas will be generated inside. At this time, the welding joints of the battery casing will be subjected to the pressure brought by the high-temperature and high-pressure gas, and the surface of the raw material plates used to form the battery casing is relatively rough at the joints, resulting in low structural strength and poor pressure bearing capacity at the welding joints of the battery casing formed after welding. It is easy to leak under the pressure of the high-temperature and high-pressure gas and has poor sealing.

[0036] Therefore, in order to improve the structural strength of the weld, enhance the pressure bearing capacity of the weld, avoid leakage under the pressure of high-temperature and high-pressure gas, and improve the sealing of the weld, this embodiment provides a battery housing.

[0037] like Figures 1 to 6 As shown, the battery shell includes a shell body 1, which includes two opposite butt joint surfaces 11. The two opposite butt joint surfaces 11 are welded to form a weld structure 12, so that the shell body 1 forms a hollow shell structure with an open opening. The butt joint surface 11 includes a bright band 111, and the width dimension of the bright band 111 along the first direction is W. The wall thickness dimension of the shell body 1 is T, and it satisfies 0.3≤W / T≤0.8.

[0038] The battery shell includes a shell body 1 composed of two butt joints 11. The width dimension W of the bright band 111 of the butt joint 11 on the shell body 1 along the first direction and the wall thickness dimension T of the shell body 1 are limited so that the width dimension W of the bright band 111 of the butt joint 11 along the first direction and the wall thickness dimension T of the shell body 1 satisfy 0.3≤W / T≤0.8, thereby ensuring that the bright band 111 of the butt joint 11 occupies a sufficient area. Therefore, when the two butt joints 11 are welded, the flat and smooth butt joint 11 can effectively improve the quality of the welding of the two butt joints 11, thereby improving the structural strength and pressure bearing capacity of the battery shell weld structure 12, avoiding leakage of the battery shell weld structure 12 under the pressure of high-temperature and high-pressure gas, and improving the sealing.

[0039] The structure of the battery shell and the range limitations of the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 can be used in various types of power batteries. However, in this embodiment, the battery shell is mainly for blade lithium-ion power batteries, whose positive and negative pole ears are located on both sides of the pole group, so the shell body 1 is a hollow shell structure with open sides.

[0040] In this embodiment, when the cutting blade cuts the plate material for making the outer shell body 1, the cross section formed by the plate material after being sheared can be divided into four areas. When the cutting blade shears the plate material, a rounded corner band 112 is formed at the upper end of the cross section of the plate material. When the cutting blade continues to press downward, the plate material is cut open by the shear force to form a bright band 111. When the cutting blade continues to move downward, the internal stress of the plate material reaches the shear limit and begins to break, forming a shearing band 113. When the cutting blade continues to move downward, a kneading band 114 is formed at the lower end of the cross section of the plate material.

[0041] In this embodiment, for the convenience of description, the trajectory of the cutting blade punching the plate material for making the shell body 1 to form the butt joint surface 11 is defined as the first direction, and X is used to represent the first direction.

[0042] As shown in Table 1, this embodiment provides fifteen groups of embodiments, so that the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 meet the range of 0.3≤W / T≤0.8, and the two butt joint surfaces 11 are subjected to a tensile test and a helium test after welding to simulate the working environment under high temperature and high pressure gas pressure, so as to judge whether the tensile strength and air tightness of the two butt joint surfaces 11 after welding meet the requirements, wherein the tensile strength is greater than 150Mpa, such as Figure 5 As shown, the breaking position is not at the weld structure 12, which meets the strength requirements. Figure 6 As shown in the figure, the breaking position is at the weld structure 12, which does not meet the strength requirements. The helium test leakage rate is less than 1×10 -7 Pa·m 3 / s, the sealing requirements are met.

[0043] Table 1

[0044]

[0045] In Example 01, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.3. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 168 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 3.2×10 -8 Pa·m 3 / s.

[0046] In Example 02, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.45. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 172 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 5.7×10 -8 Pa·m 3 / s.

[0047] In Example 03, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.55. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 174 MPa, and the fracture position is not at the weld structure 12. The helium test leakage rate is 2.5×10 -8 Pa·m 3 / s.

[0048] In Example 04, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.7. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 186 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 3.6×10 -8 Pa·m 3 / s.

[0049] In Example 05, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.8. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 198 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 2.2×10 -8 Pa·m 3 / s.

[0050] In Example 06, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.3. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 170 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 6.2×10 -9 Pa·m 3 / s.

[0051] In Example 07, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.6. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 180 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.9×10 -8 Pa·m 3 / s.

[0052] In Example 08, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.8. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 175 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 9.2×10 -9 Pa·m 3 / s.

[0053] In Example 09, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.35. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 169 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 9.2×10 -8 Pa·m 3 / s.

[0054] In Example 10, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.55. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 173 MPa, and the fracture position is not at the weld structure 12. The helium test leakage rate is 2.0×10 -8 Pa·m 3 / s.

[0055] In Example 11, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.75. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 193 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 2.9×10 -8 Pa·m 3 / s.

[0056] In Example 12, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.3. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 171 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 3.2×10 -8 Pa·m 3 / s.

[0057] In Example 13, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.45. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 175 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 6.2×10 -8 Pa·m 3 / s.

[0058] In Example 14, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.6. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 182 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.2×10 -8 Pa·m 3 / s.

[0059] In Example 15, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.8. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 196 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.2×10 -9 Pa·m 3 / s.

[0060] It can be seen from Examples 01 to 15 that the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 meet the condition limited by the range of 0.3≤W / T≤0.8. After welding, the two butt joints 11 are subjected to a tensile test and a helium test. The tensile strength of the two butt joints 11 after welding is greater than 150Mpa, and the breaking position is not at the weld structure 12. In addition, the air tightness of the two butt joints 11 after welding meets the requirements, and the helium test leakage rate is less than 1×10 -7 Pa·m 3 / s, the sealing requirements are met.

[0061] As shown in Table 2, this embodiment provides 19 groups of comparative examples. Under the condition that the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 do not meet the range limit of 0.3≤W / T≤0.8, the two butt joint surfaces 11 are subjected to a tensile test and a helium test after welding to simulate the working environment under high temperature and high pressure gas pressure to determine whether the tensile strength and air tightness of the two butt joint surfaces 11 after welding meet the requirements. If the tensile strength is greater than 150Mpa and the breaking position is not at the weld structure 12, the strength requirements are met, and the helium test leakage rate is less than 1×10 -7 Pa·m 3 / s, the sealing requirements are met.

[0062] Table 2

[0063]

[0064] In comparative example 01, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.28. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 148 MPa, and the fracture position is at the weld structure 12. The leakage rate measured by the helium test is 3.2×10 -8 Pa·m 3 / s.

[0065] In comparative example 02, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.25. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 142 MPa, and the fracture position is at the weld structure 12. The helium test leakage rate is 6.0×10 -8 Pa·m 3 / s.

[0066] In comparative example 03, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.15. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 138 MPa, and the fracture position is at the weld structure 12. The helium test leakage rate is 7.6×10 -9 Pa·m 3 / s.

[0067] In comparative example 04, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.1. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 131 MPa, and the fracture position is at the weld structure 12. The helium test leakage rate is 9.1×10 -8 Pa·m 3 / s.

[0068] In comparative example 05, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.25. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 144 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 1.9×10 -8 Pa·m 3 / s.

[0069] In comparative example 06, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.15. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 135 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 3.5×10 -8 Pa·m 3 / s.

[0070] In comparative example 07, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.25. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 146 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 7.1×10 -8 Pa·m 3 / s.

[0071] In comparative example 08, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.2. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 140 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 5.5×10 -8 Pa·m 3 / s.

[0072] In comparative example 09, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.28. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 149 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 3.1×10 -8 Pa·m 3 / s.

[0073] In comparative example 10, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.2. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 141 MPa, and the breaking position is at the weld structure 12. The leakage rate measured by the helium test is 7.3×10 -8 Pa·m 3 / s.

[0074] It can be seen from comparative examples 01 to 10 that when the ratio of the width dimension W of the bright band 111 along the first direction to the wall thickness dimension T of the shell body 1 is less than the minimum value in the range of 0.3≤W / T≤0.8, the two butt joint surfaces 11 are subjected to a tensile test and a helium test after welding. The tensile strength of the two butt joint surfaces 11 after welding is less than 150Mpa, and the breaking position is at the weld structure 12. However, the air tightness of the two butt joint surfaces 11 after welding meets the requirements, and the helium test leakage rate is less than 1×10 -7 Pa·m 3 / s, meeting the sealing requirements.

[0075] In comparative example 11, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.85. After the two butt surfaces 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt surfaces 11 are welded is 166 MPa, and the fracture position is not at the weld structure 12. The helium test leakage rate is 2.2×10 -5 Pa·m 3 / s.

[0076] In comparative example 12, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.95. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 178 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.0×10 -6 Pa·m 3 / s.

[0077] In comparative example 13, the wall thickness dimension T of the shell body 1 is set to 0.3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=1. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 186 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.2×10 -7 Pa·m 3 / s.

[0078] In comparative example 14, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.9. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 170 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 3.1×10 -7 Pa·m 3 / s.

[0079] In comparative example 15, the wall thickness dimension T of the shell body 1 is set to 1.2 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.95. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 180 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 4.9×10 -5 Pa·m 3 / s.

[0080] In comparative example 16, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.85. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 166 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 7.2×10 -6 Pa·m 3 / s.

[0081] In comparative example 17, the wall thickness dimension T of the shell body 1 is set to 2.5 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=1. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 190 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 9.0×10 -7 Pa·m 3 / s.

[0082] In comparative example 18, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=0.85. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 168 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 1.6×10 -5 Pa·m 3 / s.

[0083] In comparative example 19, the wall thickness dimension T of the shell body 1 is set to 3 mm, and the ratio between the width dimension W of the bright band 111 along the first direction and the wall thickness dimension T of the shell body 1 is set to W / T=1. After the two butt joints 11 are welded, a tensile test and a helium test are performed. It is measured that the strength of the shell body 1 when the two butt joints 11 are broken after welding is 192 MPa, and the breaking position is not at the weld structure 12. The leakage rate measured by the helium test is 3.6×10 -6 Pa·m 3 / s.

[0084] It can be seen from Comparative Examples 11 to 19 that when the ratio of the width dimension W of the bright band 111 along the first direction to the wall thickness dimension T of the shell body 1 is greater than the maximum value in the range of 0.3≤W / T≤0.8, the two butt joints 11 are subjected to a tensile test and a helium test after welding. The tensile strength of the two butt joints 11 after welding is greater than 150Mpa, and the breaking position is not at the weld structure 12. However, the helium test leakage rate of the two butt joints 11 after welding is greater than 1×10 -7 Pa·m 3 / s, does not meet the airtightness requirements.

[0085] Alternatively, if Figure 4 As shown, the weld structure 12 includes a first boss 121, and the first boss 121 protrudes toward one side of the shell body 1 along the first direction. The length dimension of the first boss 121 along the second direction is L1, and satisfies 1.4T≤L1≤2T. Since the first boss 121 is located inside the shell body 1, the length dimension L1 of the first boss 121 along the second direction is limited to satisfy 1.4T≤L1≤2T. On the one hand, it is prevented that the length dimension L1 is too small, which affects the structural strength after welding, and on the other hand, it is prevented that the length dimension L1 is too large, which occupies too much space and leads to low energy density. In this embodiment, after the welding is completed, the first boss 121 is polished to ensure that the length dimension L1 of the first boss 121 along the second direction meets the requirements.

[0086] Alternatively, if Figure 4As shown, the weld structure 12 includes a second boss 122, and the second boss 122 protrudes toward the other side of the shell body 1 along the first direction. The length dimension of the second boss 122 along the second direction is L2, and satisfies T≤L2≤1.8T. Since the second boss 122 is located outside the shell body 1, the length dimension L2 of the second boss 122 along the second direction is limited to satisfy T≤L2≤1.8T. On the one hand, it is avoided that the length dimension L2 is too small, which affects the structural strength after welding, and on the other hand, it is avoided that the length dimension L2 is too large, which affects the flatness of the outside of the battery shell. In this embodiment, after the welding is completed, the second boss 122 is polished to ensure that the length dimension L2 of the second boss 122 along the second direction meets the requirements.

[0087] In this embodiment, the two butt surfaces 11 are spliced ​​by high-frequency welding. By adopting high-frequency welding, the skin effect and the proximity effect are utilized to quickly concentrate the electrical energy on the surface of the weldment, so that the metal is quickly heated to the melting point, the heating speed is accelerated, thereby shortening the time required for the welding process and improving production efficiency.

[0088] The high-frequency welding process utilizes high-frequency current to generate resistance heat on the metal surface, heating the butt joint surface 11 to a molten state, and applying extrusion force at the same time to fuse the two butt joint surfaces 11 together for welding. When they are squeezed against each other, a first boss 121 and a second boss 122 with opposite protrusion directions are formed simultaneously. In this embodiment, for the sake of convenience, the protrusion direction of the first boss 121 and the second boss 122 is defined as the second direction, and Y is used to represent the second direction.

[0089] Optionally, the length dimension L2 of the second boss 122 is smaller than the length dimension L1 of the first boss 121. Since the second boss 122 is located on the outside of the shell body 1 and the first boss 121 is located on the inside of the shell body 1, and the flatness requirement of the outside of the shell body 1 needs to be ensured, the limitation on the second boss 122 is stricter than that on the first boss 121 located inside, that is, the length dimension L2 of the second boss 122 is ensured to be smaller than the length dimension L1 of the first boss 121.

[0090] Alternatively, if Figure 4 As shown, the height dimension of the first boss 121 protruding along the first direction is h1, and the height dimension of the second boss 122 protruding along the first direction is h2, and they satisfy 1≤h1 / h2≤4. By limiting the height dimension h1 of the first boss 121 and the height dimension h2 of the second boss 122 protruding along the first direction, so that both satisfy 1≤h1 / h2≤4, on the one hand, it is prevented that the height of the protrusion is too small, which affects the strength and air tightness after welding, and on the other hand, it is prevented that the height of the first boss 121 protruding inward is too large, which occupies space, and it is prevented that the height of the second boss 122 protruding outward is too large, which affects the flatness of the shell body 1.

[0091] Alternatively, if Figure 4 As shown, a protective fillet 123 is provided on the side of the first boss 121 away from the second boss 122. By providing the protective fillet 123 on the side of the first boss 121 away from the second boss 122, the first boss 121 is prevented from scratching the internal pole group.

[0092] Alternatively, if Figure 4 As shown, a protective rounded corner 123 is provided on the side of the second boss 122 away from the first boss 121. By providing the protective rounded corner 123 on the side of the second boss 122 away from the first boss 121, scratches on adjacent batteries are avoided when multiple batteries are combined.

[0093] Optionally, the bursting pressure of the shell body 1 is P, P≥1.2Mpa, and the wall thickness T of the shell body 1 satisfies 0.3mm≤T≤2mm. By limiting the wall thickness T of the shell body 1 to meet the requirement of 0.3mm≤T≤2mm, the bursting pressure P≥1.2Mpa of the shell body 1 is met.

[0094] In this embodiment, a battery is also provided, the battery comprising the above-mentioned battery housing, the battery further comprising a pole group and a battery cover, the battery cover is arranged at the open portion of the battery housing to form a closed accommodation cavity, and the pole group is accommodated in the accommodation cavity. By using the above-mentioned battery housing, the battery has a higher pressure bearing capacity, and avoids the battery from being scrapped due to leakage caused by the high-temperature and high-pressure gas exerting pressure on the weld structure 12 after a short period of use, thereby extending the service life of the battery and the product quality.

[0095] In this embodiment, a battery module is also provided, the battery module comprising at least two of the above-mentioned batteries. By using the above-mentioned batteries, the battery module avoids the situation that when the battery is in thermal runaway, the high-temperature and high-pressure gas is not discharged along the set position, but leaks at the weld structure 12 of the battery shell, which affects other normal operation of the battery, thereby improving the overall protection and safety of the battery module.

[0096] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A battery housing, characterized in that: The battery housing comprises a housing body, wherein the housing body comprises two opposite butt joint surfaces, and the two opposite butt joint surfaces are welded to form a weld structure, so that the housing body forms a hollow shell structure with an open opening; The butt joint surface is formed by cutting the plate material used to make the shell body with a cutting blade, and a rounded corner band, a bright band, a fracture band and a kneading band are sequentially formed on the butt joint surface. The width dimension of the bright band along the first direction is W, and the wall thickness dimension of the shell body is T, and it satisfies 0.3≤W / T≤0.

8.

2. The battery housing according to claim 1, characterized in that: The welding seam structure includes a first boss, which protrudes toward one side of the shell body along the first direction, and a length dimension of the first boss along the second direction is L1, and satisfies 1.4T≤L1≤2T.

3. The battery housing according to claim 2, characterized in that: The welding seam structure includes a second boss, the second boss protrudes toward the other side of the shell body along the first direction, the length dimension of the second boss along the second direction is L2, and satisfies T≤L2≤1.8T.

4. The battery housing according to claim 3, characterized in that: The length dimension L2 of the second boss is smaller than the length dimension L1 of the first boss.

5. The battery housing according to claim 3, characterized in that: A height dimension of the first boss protruding along the first direction is h1, a height dimension of the second boss protruding along the first direction is h2, and 1≤h1 / h2≤4 is satisfied.

6. The battery housing according to claim 5, characterized in that: A protective fillet is provided on a side of the first boss facing away from the second boss; And / or, the protective fillet is provided on a side of the second boss facing away from the first boss.

7. The battery housing according to claim 1, characterized in that: The two butt joints are joined by high frequency welding.

8. The battery housing according to claim 1, characterized in that: The bursting pressure of the shell body is P, P≥1.2Mpa, and the wall thickness dimension T of the shell body satisfies, 0.3mm≤T≤2mm.

9. A battery, characterized in that The battery comprises a battery casing as described in any one of claims 1-8, and the battery further comprises a pole group and a battery cover, wherein the battery cover is arranged on an open portion of the battery casing to form a closed accommodating cavity, and the pole group is accommodated in the accommodating cavity.

10. A battery module, characterized in that: The battery module comprises at least two batteries as claimed in claim 9.

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