Steel housing, explosion-proof steel housing, and steel housing assembly

Abstract

Disclosed in the present invention are a steel housing, an explosion-proof steel housing, and a steel housing assembly. The steel housing comprises: a shell which is open at at least one end, and a bottom cover plate for closing the opening end of the shell. The peripheral edge of the bottom cover plate is adapted to an inner cavity of the shell, and a retention space for accommodating a molten welding material is provided between the peripheral edge of the bottom cover plate and the shell. In the present application, the bottom cover plate for closing the opening end of the shell is a straight-edged plate requiring no stamping or milling of flange steps and other features, thereby making the stamping process simple and convenient, prolonging the service life of a stamping die, and allowing a wide range of selectable thicknesses for the bottom cover plate. The bottom cover plate is free of bosses and sharp corners, thus being beneficial to improve the space utilization of a battery cell inside the shell and preventing sharp corners from puncturing a blue film of the battery cell. The welding material retention space is provided between the bottom cover plate and the shell, enabling a smooth weld seam and firm welding.

Description

Steel outer shell, explosion-proof steel shell and steel shell components Technical Field

[0001] This invention relates to steel shells, explosion-proof steel shells, and steel shell assemblies. Background Technology

[0002] The stainless steel casing is a square shell welded from stainless steel material, open at both ends. A stainless steel bottom cover plate is welded to one end, forming the casing of the secondary battery. To facilitate assembly and welding with the casing, the bottom cover plate is usually stamped to form a flange step along its edge. However, this process results in a sharp corner at the top of the flange, which can easily puncture the blue film of the battery cell. At the same time, the small area of ​​the top flange is not conducive to the overall stress on the bottom of the battery cell. The R-angle in the step also makes it difficult to clean the corner. When using this method, the thickness of the bottom cover plate cannot be too thick, otherwise it will be difficult to stamp and form. Therefore, the thickness selection range of the bottom cover plate is small, stamping is difficult, and the mold life is short. CNC milling to process the step is inefficient, costly, and not conducive to mass production. Since the wall thickness of the casing is usually thin, typically made of sheet material with a thickness of 0.15mm to 0.25mm, it is easy to misalign during welding, resulting in welding defects such as weld holes, incomplete welds, weld burn-through, and molten beads.

[0003] The battery inside the sealed casing may generate high-temperature, high-pressure gas during use, potentially causing the casing to explode. To prevent this, the high-temperature, high-pressure gas inside the casing needs to be depressurized for explosion prevention. The conventional method is to stamp or CNC machine an explosion-proof countersunk hole for installing the explosion-proof valve on the bottom cover plate of the casing, and then weld the explosion-proof valve plate onto the countersunk hole. This process involves many steps. At the same time, to ensure the strength of the bottom cover plate and facilitate the welding of the explosion-proof valve plate at the countersunk hole, this cover plate needs to be relatively thick, usually around 1.5mm. Since stainless steel has a hardness of 150-180HV, the stamping and upsetting process is difficult. The thicker the cover plate, the more difficult it is to stamp, which will also greatly shorten the stamping life of the mold. Moreover, after actual stamping, the joints of each step form a rounded transition, making it impossible to clean the corners. This can easily cause interference when installing the explosion-proof valve plate, making the installation of the explosion-proof valve plate difficult and resulting in a low welding yield. On the other hand, using CNC milling to machine the steps of the explosion-proof countersunk hole is costly and slow in production efficiency, making it unsuitable for mass production. Summary of the Invention

[0004] In view of the shortcomings of the prior art, firstly, this application provides a steel shell with a straight-edged bottom cover plate that is easy to stamp and more firmly welded.

[0005] A steel casing includes a shell with an opening at at least one end and a bottom cover plate that seals the opening end of the shell. The periphery of the bottom cover plate is adapted to the inner cavity of the shell, and a retention space for accommodating molten welding material is provided at a position between the periphery of the bottom cover plate and the shell.

[0006] Secondly, this application provides an explosion-proof steel shell.

[0007] An explosion-proof steel shell includes a shell with an opening at least one end and a cover plate that seals the opening end of the shell. Explosion-proof grooves are formed on the surface of the cover plate, and the four periphery of the cover plate has a flange structure adapted to the inner wall of the shell.

[0008] Thirdly, this application also provides a steel shell assembly.

[0009] A steel shell assembly includes a shell with an opening at at least one end and a closure that seals the opening end of the shell. The closure includes a cover plate adapted to the opening end of the shell. Explosion-proof grooves are provided on the surface of the cover plate or the surface of the shell. The residual thickness of the explosion-proof grooves gradually increases or decreases from one end of the explosion-proof groove to the opposite end. Attached Figure Description

[0010] Figure 1 is an exploded view of the steel casing.

[0011] Figure 2 is a top view of the steel casing.

[0012] Figure 3 is a cross-sectional view of AA in Figure 2.

[0013] Figure 4 is an enlarged view of part A in Figure 3 of Example 1-1.

[0014] Figure 5 is a schematic diagram of the structure in Figure 4 after welding.

[0015] Figure 6 is an enlarged view of part A in Figure 3 of Examples 1-2.

[0016] Figure 7 is a schematic diagram of the structure in Figure 6 after welding.

[0017] Figure 8 is an enlarged view of part A in Figure 3 of Examples 1-3.

[0018] Figure 9 is a schematic diagram of the structure in Figure 8 after welding.

[0019] Figure 10 is an exploded view of the explosion-proof steel shell.

[0020] Figure 11 is a top view of the explosion-proof steel shell.

[0021] Figure 12 is a cross-sectional view of AA in Figure 11.

[0022] Figure 13 is an enlarged view of part A in Figure 12.

[0023] Figure 14 is an enlarged view of part B in Figure 12.

[0024] Figure 15 is an enlarged view of part A in Figure 12 of Example 2-2.

[0025] Figure 16 is an enlarged view of part A in Figure 12 of Examples 2-3.

[0026] Figure 17 is an enlarged view of part A in Figure 12 of Examples 2-4.

[0027] Figure 18 is a schematic diagram of the stamping head used for engraving explosion-proof marks.

[0028] Figure 19 is a perspective view of the steel shell assembly.

[0029] Figure 20 is an exploded view of the steel shell assembly.

[0030] Figure 21 is a top view of the steel shell assembly.

[0031] Figure 22 is a top view of the steel shell assembly after the protective film has been removed.

[0032] Figure 23 is a cross-sectional view of AA in Figure 21.

[0033] Figure 24 is an enlarged view of part A in Figure 23.

[0034] Figure 25 is an enlarged view of part B in Figure 23 of Example 3-1.

[0035] Figure 26 is an enlarged view of part A in Figure 23 of Example 3-2.

[0036] Figure 27 is an enlarged view of part A in Figure 23 of Example 3-3.

[0037] Figure 28 is an enlarged view of part A in Figure 23 of Examples 3-4. Detailed Implementation

[0038] Firstly, this application provides a steel casing.

[0039] Example 1-1

[0040] This embodiment discloses a steel shell with a straight-edged bottom cover plate 20, as shown in Figures 1-4. It includes a shell 10 with at least one open end and a bottom cover plate 20 that seals one open end of the shell 10. The periphery of the bottom cover plate 20 is adapted to the inner cavity of the shell 10, and a retention space for accommodating molten welding material is provided at the position between the periphery of the bottom cover plate 20 and the shell 10.

[0041] In this embodiment, the housing 10 is a cylindrical body with openings at both the top and bottom. The bottom cover plate 20 is disposed on one end of the housing 10 to close the opening. In this configuration, after the battery cell is installed inside the housing 10, the other open end of the housing 10 is closed with an electrode cover plate to form a power battery or battery pack. It can be understood that the housing 10 can also be closed at one end and open at the other end, with the bottom cover plate 20 disposed on the open end to close the opening. In this embodiment, the housing 10 is made of stainless steel sheet with a thickness of 0.15mm to 0.3mm. Referring to Figures 1-3, the housing 10 in this embodiment is a rectangular thin-walled cylindrical body with openings at both the top and bottom, including two oppositely arranged... The shell 10 has a wide sidewall and two oppositely arranged narrow sidewalls. The bottom cover plate 20 is a rectangular plate that fits the opening of the rectangular cylindrical shell 10. It can be understood that in other feasible embodiments, the shell 10 can also be a thin-walled cylindrical body in the shape of a square, circle or other polygon. Correspondingly, the shape of the bottom cover plate 20 is adapted to the shape of the opening end of the shell 10. After the shell 10 is made, the bottom cover plate 20 is fixedly connected to the shell 10 by welding. After being fixedly connected to the shell 10, the bottom cover plate 20 seals the opening end of the shell 10. In this embodiment, the shell 10 is placed vertically and the bottom cover plate 20 is set at the upper opening end of the shell 10 as an example for explanation.

[0042] Referring to Figures 1-5, the bottom cover plate 20 is a rectangular straight-edged plate that fits into the opening of the housing 10. In this embodiment, the bottom cover plate 20 is made of stainless steel or aluminum plate with a thickness of 0.4mm to 2.0mm. In a feasible embodiment, based on the design strength of the steel housing, the bottom cover plate 20 is preferably made of 0.6mm thick stainless steel plate. Specifically, it can be formed by stamping and cutting or laser cutting. In this embodiment, the housing 10 is preferably made of 0.2mm thick stainless steel plate. Since the thickness of the housing 10 is relatively thin, it cannot be manufactured by stamping. The housing 10 is manufactured by stamping, cutting, bending, and welding. When the bottom cover plate 20 is placed at the port of the housing 10 to seal the opening of the housing 10, the outer wall of the bottom cover plate 20 fits the inner wall of the housing 10. The upper surface of the bottom cover plate 20 is 0.3mm higher than the upper end surface of the housing 10, thus forming a gap between the upper end surface of the housing 10 and the outer peripheral surface of the bottom cover plate 20. A welding step is formed, which creates a retention space 301a for accommodating molten welding material. At this time, the insertion depth of the bottom cover plate 20 into the shell is 0.3 mm (the insertion depth of the bottom cover plate 20 is defined as the distance between the lower surface of the bottom cover plate 20 and the upper end face of the shell 10 in the height direction of the shell 10). When the bottom cover plate 20 is welded to the shell 10 using a laser hybrid welding process, the laser beam is directed horizontally towards the bottom cover plate 20 at the retention space 301a. The molten welding wire, the upper surface of the shell 10, and the outer peripheral surface of the bottom cover plate 20 melt and fill the reserved space 301a to form a molten pool 401a. During welding, under the blowing of the welding shielding gas, the reserved space 301a is eventually filled with a rounded molten pool 401a, resulting in a smooth and full weld scar. This increases the contact area between the bottom cover plate 20, the shell 10, and the molten pool 401a, thus making the bottom cover plate 20 and the shell 10 welded firmly and reliably.To facilitate the insertion of the lower part of the bottom cover plate 20 into the housing 10, a second rounded chamfer 203 is provided on all four periphery of the lower surface of the bottom cover plate 20. In this embodiment, the radius R2 of the second rounded chamfer 203 is 0.15mm. Since R2 is less than the insertion depth of the bottom cover plate 20 into the housing (0.3mm), a portion of the outer periphery of the bottom cover plate 20 contacts the inner wall of the housing 10, ensuring stable positioning. In another feasible embodiment, based on the design strength of the steel housing, the bottom cover plate 20 is preferably made of 0.4mm thick stainless steel plate. Specifically, it can be formed by stamping, shearing, or laser cutting. In this embodiment, the housing 10 is preferably made of stainless steel plate with a thickness of 0.15mm. When the bottom cover plate 20 is placed at the port of the housing 10 to seal the opening end of the housing 10, the outer wall of the bottom cover plate 20 is adapted to the inner wall of the housing 10, and the upper surface of the bottom cover plate 20 is 0.2mm higher than the upper end face of the housing 10. This forms a relatively small welding step between the upper end face of the housing 10 and the outer peripheral surface of the bottom cover plate 20, and the resulting retention space 301a is also relatively reduced. At this time, the insertion depth of the bottom cover plate 20 into the housing is 0.2mm. Since the thickness of the bottom cover plate 20 is reduced at this time, in this embodiment, the first The radius R2 of the double chamfer 203 is set to 0.1mm, so part of the outer peripheral surface of the bottom cover plate 20 contacts the inner wall surface of the housing 10, and the positioning is stable. In another feasible embodiment, according to the design strength of the steel housing, the bottom cover plate 20 is preferably made of 2mm thick stainless steel plate. Specifically, it can be made by stamping and cutting or laser cutting. In this embodiment, the housing 10 is preferably made of 0.3mm thick stainless steel plate. When the bottom cover plate 20 is placed at the port of the housing 10 to seal the opening end of the housing 10, the outer wall of the bottom cover plate 20 is adapted to the inner wall of the housing 10. The upper surface of the bottom cover plate 20 is 0.4 mm higher than the upper end face of the housing 10, thus forming a relatively high welding step between the upper end face of the housing 10 and the outer peripheral surface of the bottom cover plate 20. This also increases the size of the resulting space 301a. At this point, the insertion depth of the bottom cover plate 20 is 1.6 mm (the insertion depth of the bottom cover plate 20 is defined as the distance between the lower surface of the bottom cover plate 20 and the upper end face of the housing 10 in the height direction of the housing 10). In this embodiment, the radius R2 of the second chamfer 203 is set to 0.5 mm, so part of the outer peripheral surface of the bottom cover plate 20 contacts the inner wall surface of the housing 10, ensuring stable positioning. Of course, the thickness of the housing 10, the thickness of the bottom cover plate 20, the distance between the upper surface of the bottom cover plate 20 and the upper end face of the housing 10, and the radius R2 of the second chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be flexibly selected according to the specific design requirements of the steel housing, and will not be elaborated further here.In the above scheme, since the bottom cover plate 20 is a straight-edge plate and no upward or downward protruding steps or flanges are formed at the edge of the bottom cover plate 20, the internal space of the shell 10 is relatively large and the utilization rate is higher when this straight-edge bottom cover plate 20 is sealed and welded to the open end of the shell 10. It should be noted that the welding materials in this application not only include the welding wire used when welding the bottom cover plate to the shell using laser composite welding, but also, in other feasible embodiments, when laser welding is used, the welded body (such as the shell and bottom cover plate in this scheme) melts under the irradiation of the laser and fills the preset retention space to form a molten pool. The molten welded body in this molten pool also belongs to the welding materials referred to in this application.

[0043] Examples 1-2

[0044] In this embodiment, as shown in Figures 3, 6, and 7, the upper surface of the bottom cover plate 20 is flush with the upper end face of the shell 10. A first rounded chamfer 202 is provided along the four periphery of the bottom cover plate 20. The first rounded chamfer 202 and the upper inner wall of the shell 10 enclose a space 301b. When the bottom cover plate 20 and the shell 10 are welded using filler wire welding, the molten welding wire fills the space 301b formed by the first rounded chamfer 202 and the upper inner wall of the shell 10, forming a molten pool 401b. Under the blowing state of the protective gas during welding, the surface of the molten pool 401b is flat and smooth. Because this space 301b forms the molten pool 401b, the contact area between the bottom cover plate 20, the shell 10, and the molten pool 401b is increased, thus ensuring a firm and reliable weld between the bottom cover plate 20 and the shell 10. In one feasible implementation, when the thickness of the cover plate is set to 0.4mm according to the design strength of the steel shell, the shell 10 can be made of 0.15mm stainless steel plate. In this case, the radius R1 of the first rounded chamfer 202 can be set to 0.15mm, and the resulting space 301b is relatively small. The radius R2 of the second rounded chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be set to 0.1mm to 0.3mm, preferably 0.1mm. This ensures that part of the outer peripheral surface of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10, resulting in stable positioning between the bottom cover plate 20 and the shell 10, facilitating welding. When the thickness of the cover plate is set to 0.6mm according to the design strength of the steel shell, the shell 10 can be made of 0.2mm stainless steel plate. In this case, the radius R1 of the first rounded chamfer 202 can be set to... The radius R2 of the second rounded chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be set to 0.1mm to 0.3mm, preferably 0.2mm. This ensures that part of the outer periphery of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10, resulting in stable positioning between the bottom cover plate 20 and the shell 10 and facilitating welding. When higher strength of the steel shell is required, such as when the thickness of the bottom cover plate 20 is set to 2mm, the shell 10 can be made of 0.3mm stainless steel plate. In this case, the radius R1 of the first rounded chamfer 202 can be set to 0.5mm, and the radius R2 of the second rounded chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be set to 0.3mm. This ensures that part of the outer periphery of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10, resulting in stable positioning between the bottom cover plate 20 and the shell 10 and facilitating welding.

[0045] Examples 1-3

[0046] In this embodiment, as shown in Figures 3, 8, and 9, the upper surface of the bottom cover plate 20 is flush with the upper end face of the shell 10. A chamfer 201 is provided along the four perimeters of the bottom cover plate 20. The chamfer 201 and the upper inner wall of the shell 10 enclose a space 301c. When the bottom cover plate 20 and the shell 10 are welded using filler wire welding, the molten welding wire fills the space 301c formed by the chamfer 201 and the upper inner wall of the shell 10, forming a molten pool 401c. Under the blowing state of the protective gas during welding, the surface of the molten pool 401c is flat and smooth. Because this space 301c forms the molten pool 401c, it increases the contact area between the bottom cover plate 20, the shell 10, and the molten pool 401c, thus ensuring a firm and reliable weld between the bottom cover plate 20 and the shell 10. In one feasible implementation, when the thickness of the cover plate is set to be relatively thin according to the design strength of the steel shell, such as when the thickness of the cover plate is 0.4mm, the shell 10 can be made of 0.15mm stainless steel plate. In this case, the vertical chamfer distance of the straight chamfer 201 can be set to 0.15mm, and the horizontal chamfer distance can be set to 0.1mm. The resulting clearance space 301c is also relatively small. The radius R2 of the second round chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be set to 0.1mm to 0.3mm, preferably 0.1mm. Thus, part of the outer peripheral surface of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10, and the bottom cover plate 20 and the shell 10 are stably positioned, facilitating welding. When the thickness of the cover plate is set to be 0.6mm according to the design strength of the steel shell, the shell 10 can be made of 0.2mm stainless steel plate. In this case, the vertical chamfer distance of the straight chamfer 201 can be set to 0.2mm, and the horizontal chamfer distance can be set to 0.15mm. The chamfer distance can be set to 0.15mm, and the radius R2 of the second round chamfer 203 on the four periphery of the lower surface of the bottom cover plate 20 can be set to 0.1mm to 0.3mm, preferably 0.2mm. This ensures that part of the outer periphery of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10, resulting in stable positioning between the bottom cover plate 20 and the shell 10, facilitating welding. When higher strength is required for the steel shell, such as when the thickness of the bottom cover plate 20 is set to 2mm, the shell 10... It can be made of 0.3mm stainless steel plate. In this case, the vertical chamfer distance of the straight chamfer 201 can be set to 0.3mm, and the horizontal chamfer distance can be set to 0.2mm. The resulting space 301c is also relatively large. The radius R2 of the second round chamfer 203 on the four sides of the lower surface of the bottom cover plate 20 can be set to 0.5mm. As a result, part of the outer peripheral surface of the bottom cover plate 20 is in surface contact with the inner wall of the shell 10. The bottom cover plate 20 and the shell 10 are stably positioned and easy to weld.

[0047] Compared with the steel shell formed by stamping or milling a bottom cover plate 20 with flange steps and welding it to a thin-walled shell 10, the bottom cover plate 20 used to seal the opening of the shell 10 in this application is a straight-edged plate, which does not require stamping or milling of flange steps and other features. Therefore, stamping is convenient and simple, the cost is lower, the stamping die life is longer, the thickness of the bottom cover plate 20 can be selected in a wide range, and the bottom cover plate 20 has no bosses or sharp corners, which is conducive to increasing the space utilization of the battery cells inside the shell 10 and preventing sharp corners from piercing the blue film of the battery cells. A space for molten welding material is provided between the bottom cover plate 20 and the shell 10 to form a molten pool. Under the blowing of the welding shielding gas, the molten pool is smooth and full, and the welding is more solid.

[0048] Secondly, this application also provides an explosion-proof steel shell.

[0049] Example 2-1

[0050] This embodiment discloses an explosion-proof steel shell, as shown in Figure 10, including a shell 10 with an opening at least one end and a cover plate 20 that seals the opening end of the shell 10. Explosion-proof grooves 201 are formed on the surface of the cover plate 20, and the four periphery of the cover plate 20 are formed with flange structures that are adapted to the inner wall of the shell 10. It can be understood that the explosion-proof grooves 201 can also be provided on the surface of the shell 10, that is, the explosion-proof grooves 201 can be provided on the outer wall of the shell 10 or on the inner wall of the shell 10. In this embodiment, only the explosion-proof grooves 201 are provided on the surface of the cover plate 20 for description.

[0051] In this embodiment, the housing 10 is a cylindrical body with openings at both the top and bottom. The cover plate 20 is disposed on one end of the housing 10 to close the opening. In this configuration, the battery cell is installed inside the housing 10, and then the other opening is closed to form a power battery or battery pack. Understandably, the housing 10 can also be closed at one end and open at the other, with the cover plate 20 disposed on the open end to close the opening. In this embodiment, the housing 10 is made of stainless steel sheet with a thickness of 0.15mm to 0.25mm through cutting, bending, and welding. Preferably, it is made of stainless steel sheet with a thickness of 0.2mm. Referring to Figures 10 and 11, the housing 10 in this embodiment is a rectangular thin-walled structure with openings at both the top and bottom. The cylindrical body includes two oppositely arranged wide sidewalls and two oppositely arranged narrow sidewalls. The cover plate 20 is a rectangular plate that fits the opening of the rectangular cylindrical body 10. It can be understood that in other feasible embodiments, the body 10 can also be a square or other shape thin-walled cylindrical body. Correspondingly, the shape of the cover plate 20 is adapted to the shape of the opening end of the body 10. After the body 10 is manufactured, the cover plate 20 is fixedly connected to the body 10 by welding. After being fixedly connected to the body 10, the cover plate 20 seals the opening end of the body 10. In this embodiment, the body 10 is placed vertically and the cover plate 20 is set at the upper opening end of the body 10 as an example for explanation.

[0052] The cover plate 20 is a rectangular plate. The position of the explosion-proof markings 201 on the surface of the cover plate 20 can be determined according to the internal assembly of the housing 10, and can be set at any desired position on the cover plate 20. In this embodiment, the explosion-proof markings 201 are set at the middle position of the cover plate 20. Referring to Figures 11-14, the explosion-proof markings 201 are formed by stamping. The projection of the trajectory of the explosion-proof markings 201 on the surface of the cover plate 20 can be set as an ellipse, circle, square or other closed curve, as shown in Figures 10 and 11. In this embodiment, the explosion-proof markings 201 are... The trajectory of 01 is set as an elliptical curve along the length of the cover plate 20. Referring to Figures 12-14, the residual thickness of the explosion-proof notch 201 is 0.07mm to 0.14mm. As shown in Figure 14, the residual thickness of the explosion-proof notch 201 is defined as the remaining thickness H of the cover plate 20 after it is stamped and recessed at the explosion-proof notch 201. The explosion-proof notch 201 is formed only by the surface of the cover plate 20 recessing into the body of the cover plate 20. The opposite surface of the cover plate 20 remains flat and will not produce any protruding features at the location corresponding to the explosion-proof notch 201. The cross-section of the explosion-proof notch 201 can be a U-shaped groove, a V-shaped groove, or an inverted trapezoidal groove, as shown in Figures 13 and 14. In this embodiment, the explosion-proof notch 201 is preferably an inverted trapezoidal groove, thereby forming an explosion-proof valve for depressurizing the inner cavity of the housing 10 at the explosion-proof notch 201. Since the explosion-proof valve is stamped integrally with the cover plate 20, there is no need to separately assemble and weld the explosion-proof sheet. Therefore, the cover plate 20 does not need to be relatively thick due to the feasibility of assembling and welding with the explosion-proof sheet. In typical designs, this method of welding the explosion-proof sheet usually requires the cover plate 20 to be at least 1.5mm thick to ensure good welding of the individual explosion-proof sheet to the cover plate 20. Therefore, since there is no need to weld the explosion-proof sheet to the cover plate 20, this solution uses a stamped integrally formed cover plate 20. It can be formed by stamping thinner sheets or plates, such as stainless steel sheets or plates with a thickness of 0.15mm to 0.35mm. For example, it can be formed by stamping stainless steel sheets or plates with a thickness of 0.15mm, 0.2mm, 0.25mm or 0.35mm. In this solution, the cover plate 20 is preferably made of 0.2mm stainless steel sheet or plate. Therefore, due to the thinner thickness, the cover plate 20 of the integrated explosion-proof valve is easier to stamp and form, the process is simpler, the production efficiency is higher and the yield rate is higher. Thus, since the residual thickness at the explosion-proof notch 201 is smaller than the thickness at other locations of the cover plate 20, when the cover plate 20 is welded and fixed to the housing 10, when the pressure of the high-pressure gas generated in the housing 10, which is sealed at both ends, reaches the preset value, it will first crack at the explosion-proof notch 201 on the surface of the cover plate 20 to release pressure, preventing the gas pressure in the housing 10 from rising continuously and causing a more severe explosion of the entire housing 10, thereby achieving the purpose of pressure relief and explosion prevention.In this embodiment, the explosion-proof groove 201 is provided on the upper surface of the cover plate 20. To prevent other corrosive liquids or impurities from entering the explosion-proof groove 201 and corroding it, a protective film needs to be pasted on the upper surface of the cover plate 20 to protect the explosion-proof groove 201. In other feasible embodiments, the explosion-proof groove 201 can be provided on the lower surface of the cover plate 20. The explosion-proof groove 201 provided on the lower surface of the cover plate 20 can keep the upper surface of the cover plate 20 flat and beautiful, and there is no need to paste a protective film to protect the explosion-proof groove 201.

[0053] As an improvement to this embodiment, referring to Figures 12 to 14, the residual thickness of the explosion-proof marking 201 gradually increases or decreases from one end of the cover plate 20 to the opposite end. Please refer to Figure 18, which is a schematic diagram of a mold for stamping a head 30 to form the explosion-proof marking 201 on the surface of the cover plate 20. In this mold, the protrusion height of the protrusion 301 used to form the explosion-proof marking 201 gradually decreases or increases from one end of the head 30 to the opposite end. Therefore, the residual thickness of the explosion-proof marking 201 stamped on the surface of the cover plate 20 by the head 30 gradually increases or decreases from one end of the cover plate 20 to the opposite end. In this embodiment, the residual thickness of the explosion-proof marking 201 gradually increases or decreases along the length direction of the cover plate 20. It can be understood that in other feasible embodiments, the residual thickness of the explosion-proof marking 201 may also gradually increase or decrease along the width direction of the cover plate 20. In this embodiment, the residual thickness of the thinner end of the explosion-proof groove 201 can be set to 0.07mm to 0.09mm, and the residual thickness of the thicker end of the explosion-proof groove 201 can be set to 0.12mm to 0.14mm. Preferably, when the thickness of the cover plate 20 is 0.2mm, the residual thickness of the thinner end of the explosion-proof groove 201 is set to 0.08mm, and the residual thickness of the thicker end of the explosion-proof groove 201 is set to 0.13mm. Thus, because the residual thickness of the explosion-proof groove 201 gradually changes, when high pressure is generated inside the housing 10, each time a burst occurs, the cracking begins at the point where the residual thickness of the explosion-proof groove 201 is the smallest, and then gradually extends towards the end where the residual thickness of the explosion-proof groove 201 is thicker. The burst pressure relief is more stable. However, if the residual thickness of the explosion-proof groove 201 is set to be equal and unchanged, the location where the explosion-proof groove 201 begins to crack when the housing 10 bursts is unpredictable, or the entire explosion-proof groove 201 may burst simultaneously, causing the cover plate 20 to detach from the housing 10. In comparison, the variable residual thickness of the explosion-proof groove 201 in this solution makes the burst stability and controllability stronger.Understandably, when the residual thickness of the explosion-proof notch 201 is gradually varying, the projection of the trajectory of the explosion-proof notch 201 onto the cover plate surface can also be an unclosed curve. In this case, the residual thickness at the thicker end of the explosion-proof notch 201 is equal to the thickness of the cover plate 20. In this configuration, when high pressure is generated inside the housing 10, each time a burst occurs at the explosion-proof notch 201 to release pressure, the cracking begins at the position with the smallest residual thickness of the explosion-proof notch 201, and then gradually progresses towards the position with the smallest residual thickness of the explosion-proof notch 201. The thicker end extends and cracks, but since the thickness of the thicker end of the residual thickness of the explosion-proof groove 201 is the same as the thickness of the cover plate 20, compared with the explosion-proof groove 201 whose trajectory is a closed curve, the thickness of the thicker end of the residual thickness of this explosion-proof groove 201 whose trajectory is not closed is thicker. Therefore, the phenomenon that the entire explosion-proof groove 201 will completely crack when the housing 10 is burst and depressurized will not occur. This effectively avoids the situation where the cover plate 20 is splashed off and damages other components when the housing 10 is burst and depressurized.

[0054] In this embodiment, a steel pressure plate can be provided below the cover plate 20 to strengthen the cover plate 20 and improve its resistance to deformation. The steel pressure plate can be pasted on the lower surface of the cover plate 20. The length and width of the steel pressure plate are correspondingly smaller than the length and width of the cover plate 20. A through hole is provided in the middle of the steel pressure plate to cooperate with the explosion-proof notch 201, so that the pressure generated inside the housing 10 can be directly applied to the explosion-proof notch 201 on the cover plate 20. With the strengthening effect of the steel pressure plate, the thickness of the cover plate 20 can be as thin as possible, such as 0.15mm, while meeting the required strength of the cover plate 20. This makes the stamping and forming of the cover plate 20 easier and the yield rate higher.

[0055] Referring to Figures 12 and 13, in this embodiment, the flange structure includes a downward-facing flange 205a formed along the four periphery of the cover plate 20. The outer wall of the flange 205a is adapted to the inner wall of the housing 10. When a steel pressure plate is attached to the lower surface of the cover plate 20, the height of the flange 205a is less than the thickness of the steel pressure plate and the cover plate 20 combined (the height of the flange 205a is defined as the distance from the upper surface of the cover plate 20 to the lower end face of the flange 205a). Thus, the lower end of the flange 205a will not extend downward beyond the lower surface of the steel pressure plate below the cover plate 20, and will not interfere with components such as the battery cell installed inside the housing 10. In this embodiment, the height of the flange is 0.5mm to 0.7mm. m, preferably 0.6mm. Due to the setting of the flange 205a, the edge of the cover plate 20 has a certain elasticity. When the outer wall of the flange 205a is matched with the inner wall of the housing 10 to cover the upper port of the housing 10, the cover plate 20 is easier to assemble at the upper port of the housing 10. In this embodiment, when the cover plate 20 is assembled at the upper port of the housing 10, the insertion depth of the flange 205a into the housing is 0.25mm to 0.45mm (the insertion depth of the flange 205a is defined as the distance between the lower end face of the flange 205a and the upper end face of the housing 10). Preferably, the insertion depth of the flange 205a into the housing is 0.3mm. Of course, the insertion depth of the flange 205a into the housing can be reasonably adjusted according to the product specifications. In this embodiment, when the cover plate 20 is assembled onto the upper port of the housing 10 to close the upper port of the housing 10, the upper surface of the cover plate 20 is 0.15mm to 0.4mm higher than the upper end face of the housing 10, such as 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm or 0.4mm. Preferably, the upper surface of the cover plate 20 is 0.3mm higher than the upper end face of the housing 10, so that the upper surface of the cover plate 20 and the upper end face of the housing 10 form a welding step 203a that facilitates welding the cover plate 20 and the housing 10 together. Thus, when the cover plate 20 and the housing 10 are fused together by laser welding at the welding step 203a, a molten pool 204a is formed at the welding step 203a, filling the welding step 203a. During welding, under the blowing state of the protective gas, the molten pool 204a is full in shape and naturally forms a rounded corner state, resulting in a better welding effect.

[0056] Example 2-2

[0057] Referring to Figures 12 and 15, in this embodiment, the flange structure includes a U-shaped flange 205b with an upward opening formed along the four periphery of the cover plate 20. The outer wall of the U-shaped flange 205b is adapted to the inner wall of the housing 10. When a steel pressure plate is attached to the lower surface of the cover plate 20, the lower end face of the U-shaped flange 205b is located above the plane containing the lower surface of the steel pressure plate, or the lower end face of the U-shaped flange 205b is flush with the lower surface of the steel pressure plate. In this way, the lower end of the U-shaped flange 205b will not extend downward beyond the lower surface of the steel pressure plate below the cover plate 20, and will not interfere with components such as the battery cell installed in the housing 10. The upper end face of the U-shaped flange 205b is flush with the upper end face of the cover plate 20 or located below the plane containing the upper end face of the cover plate 20. Preferably, the upper end face of the U-shaped flange 205b is located below the plane containing the upper end face of the cover plate 20. Because the U-shaped flange... The flange 205b provides a certain degree of elasticity to the edge of the cover plate 20. When the outer wall of the U-shaped flange 205b is fitted with the inner wall of the housing 10 to cover the upper port of the housing 10, the cover plate 20 is more easily assembled onto the upper port of the housing 10. In this embodiment, the height of the U-shaped flange 205b is 0.6mm to 1.0mm (the height of the U-shaped flange 205b is defined as the distance from the upper surface of the cover plate 20 to the lower end face of the U-shaped flange 205b). Preferably, the depth of the U-shaped flange 205b is 0.25mm to 0.45mm after the cover plate 20 is assembled on the upper end of the housing 10. (The depth of the U-shaped flange 205b is defined as the distance between the lower end face of the U-shaped flange 205b and the upper end face of the housing 10). Preferably, the depth of the U-shaped flange 205b is 0.3mm. Of course, the depth of the U-shaped flange 205b can be reasonably adjusted according to the product specifications. In this embodiment, when the cover plate 20 is assembled to the upper port of the housing 10 to close the upper port of the housing 10, the upper end surface of the U-shaped flange 205b is 0.15mm to 0.4mm higher than the upper end surface of the housing 10, such as 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm or 0.4mm. Preferably, the upper end surface of the U-shaped flange 205b is 0.2mm higher than the upper end surface of the housing 10, so that the upper surface of the cover plate 20 and the upper end surface of the housing 10 form a welding step 203b that facilitates welding the cover plate 20 and the housing 10 together. Thus, when the cover plate 20 and the housing 10 are fused together by laser welding at the welding step 203b, a molten pool 204b is formed at the welding step 203b to fill the welding step 203b. During welding, under the blowing state of the protective gas, the molten pool 204b is full in shape and naturally forms a rounded corner state, resulting in a better welding effect.

[0058] Example 2-3

[0059] Referring to Figures 12 and 16, in this embodiment, the flange structure includes a U-shaped flange 205c with an upward opening formed along the four periphery of the cover plate 20. The outer wall of the U-shaped flange 205c is adapted to the inner wall of the housing 10. When a steel pressure plate is attached to the lower surface of the cover plate 20, the lower end face of the U-shaped flange 205c is located above the plane containing the lower surface of the steel pressure plate, or the lower end face of the U-shaped flange 205c is flush with the lower surface of the steel pressure plate. In this way, the lower end of the U-shaped flange 205c will not extend downward beyond the cover plate 20. The lower surface of the steel pressure plate below 0 will not interfere with components such as the battery cell installed in the housing 10. The upper end face of the U-shaped flange 205c is flush with the upper end face of the cover plate 20 or located in the space below the plane where the upper end face of the cover plate 20 is located. Preferably, the upper end face of the U-shaped flange 205c is located in the space below the plane where the upper end face of the cover plate 20 is located. The height of the U-shaped flange is 0.6mm to 1.0mm (the height of the U-shaped flange 205c is defined as the distance from the upper surface of the cover plate 20 to the lower end face of the U-shaped flange 205c), preferably 0.8mm. Because the U-shaped flange 205c provides a certain degree of elasticity to the edge of the cover plate 20, when the outer wall of the U-shaped flange 205c is fitted with the inner wall of the housing 10 to cover the upper port of the housing 10, the cover plate 20 is more easily assembled onto the upper port of the housing 10. In this embodiment, after the cover plate 20 is assembled onto the upper port of the housing 10, the insertion depth of the U-shaped flange 205c into the housing is 0.4mm to 0.6mm (the insertion depth of the U-shaped flange 205c is defined as the distance between the lower end face of the U-shaped flange 205c and the upper end face of the housing 10). Preferably, the insertion depth of the U-shaped flange 205c into the housing is 0.5mm. Of course, the insertion depth of the U-shaped flange 205c into the housing can be reasonably adjusted according to the product specifications. In this embodiment, when the cover plate 20 is assembled onto the upper port of the housing 10 to close the upper port of the housing 10, the upper end face of the U-shaped flange 205c is flush with the upper end face of the housing 10. When laser welding is used, welding is performed at the gap between the housing 10 and the U-shaped flange 205c, and a molten pool 204c is formed at the gap between the upper end face of the housing 10 and the upper end face of the U-shaped flange 205c.

[0060] Examples 2-4

[0061] Referring to Figures 12 and 17, in this embodiment, the flange structure includes a U-shaped flange 205d with an upward opening formed along the four periphery of the cover plate 20. The outer wall of the U-shaped flange 205d is adapted to the inner wall of the housing 10. When a steel pressure plate is attached to the lower surface of the cover plate 20, the lower end face of the U-shaped flange 205d is located above the plane of the lower surface of the steel pressure plate, or the lower end face of the U-shaped flange 205d is flush with the lower surface of the steel pressure plate. In this way, the lower end of the U-shaped flange 205d will not extend downward beyond the lower surface of the steel pressure plate below the cover plate 20, and will not interfere with components such as battery cells installed in the housing 10. The upper end face of the U-shaped flange 205d is flush with or located above the upper end face of the cover plate 20. The space below the plane where the upper end face of the cover plate 20 is located, preferably, the upper end face of the U-shaped flange 205d is located in the space below the plane where the upper end face of the cover plate 20 is located. The height of the U-shaped flange 205d is 0.6mm to 1.0mm (the height of the U-shaped flange 205d is defined as the distance from the upper surface of the cover plate 20 to the lower end face of the U-shaped flange 205d), preferably 0.8mm. The upper end face of the U-shaped flange 205d extends horizontally to form an overlap 202. In this embodiment, when the cover plate 20 is assembled to the upper port of the housing 10 to close the upper port of the housing 10, the lower surface of the overlap 202 is in contact with the upper end face of the housing 10, and the outer peripheral surface of the overlap 202 is flush with the outer wall of the housing 10. When laser welding is used, welding is performed at the gap between the shell 10 and the overlap 202, and a molten pool 204d is formed at the gap between the upper outer wall of the shell 10 and the outer peripheral surface of the overlap 202.

[0062] Thirdly, this application also provides a steel shell assembly with an integrated explosion-proof valve structure.

[0063] Example 3-1

[0064] The steel shell assembly disclosed in this embodiment, as shown in Figures 19-23, includes a shell 10 with at least one open end and a sealing member 20 that seals one open end of the shell 10. The sealing member 20 includes a cover plate 201 adapted to the open end of the shell 10. Explosion-proof grooves 2022 are provided on the surface of the cover plate 201 or the shell 10. A pressure relief portion 202 is formed on the cover plate 201. The pressure relief portion 202 includes a groove 2021 formed on the cover plate 201. Explosion-proof grooves 2022 are provided on the surface of the groove 2021.

[0065] In this embodiment, the housing 10 is a cylindrical body with openings at both the top and bottom. The sealing member 20 is disposed on one end of the housing 10 to close the opening. In this configuration, the battery cell is installed inside the housing 10, and then the other opening is closed to form a power battery or battery pack. Understandably, the housing 10 can also be closed at one end and open at the other end, with the sealing member 20 disposed on the open end to close the opening. In this embodiment, the housing 10 is made of stainless steel sheet with a thickness of 0.15mm to 0.25mm through cutting, punching positioning holes, bending, and welding. Preferably, it is made of stainless steel sheet with a thickness of 0.2mm. Referring to Figure 23, the housing 10 in this embodiment is a rectangular thin-walled structure with openings at both the top and bottom. The cylindrical body includes two oppositely arranged wide sidewalls and two oppositely arranged narrow sidewalls. The closure member 20 is a rectangular plate adapted to the opening of the rectangular cylindrical body shell 10. It can be understood that in other feasible embodiments, the shell 10 can also be a square or other shape thin-walled cylindrical body. Correspondingly, the shape of the closure member 20 is adapted to the shape of the opening end of the shell 10. After the shell 10 is manufactured, the closure member 20 is fixedly connected to the shell 10 by welding. After being fixedly connected to the shell 10, the closure member 20 seals the opening end of the shell 10 at that location. In this embodiment, the shell 10 is placed vertically and the closure member 20 is set at the upper opening end of the shell 10 as an example for explanation.

[0066] The cover plate 201 is a rectangular plate. The position of the recessed groove 2021 on the cover plate 201 can be determined according to the internal assembly of the housing 10. It can be set at any desired position on the cover plate 201. In this embodiment, the recessed groove 2021 is set at the middle position of the cover plate 201. Referring to Figures 20 and 23, the recessed groove 2021 can be formed by stamping the middle position of the cover plate 201 protruding towards the inner cavity of the housing 10. Then, explosion-proof grooves 2022 are stamped on the surface of the recessed groove 2021. The recessed groove 2021 can be set as a circular groove, a square groove, or a groove of other shapes, as shown in Figures 19 to 22. In this embodiment, the recessed groove 2021 is set as an elliptical groove along the length direction of the cover plate 201. Referring to Figures 23-25, on the surface near the recessed groove 2021 An explosion-proof groove 2022 with a closed curve trajectory is etched along the edge. The residual thickness of the explosion-proof groove 2022 is 0.07mm to 0.14mm, as shown in Figure 25. The residual thickness of the explosion-proof groove 2022 is defined as the remaining thickness H of the cover plate 201 after being stamped and recessed at the explosion-proof groove 2022. The explosion-proof groove 2022 is formed only by the upper surface of the groove 2021 recessed towards the inner cavity of the housing 10. The lower surface of the groove 2021 remains flat and will not have a downward protrusion at the location corresponding to the explosion-proof groove 2022. The cross-section of the explosion-proof groove 2022 can be a U-shaped groove, a V-shaped groove, or an inverted trapezoidal groove, as shown in Figure 25. In this embodiment, the explosion-proof groove 2022 is preferably an inverted trapezoidal groove. Thus, an explosion-proof valve for depressurizing the inner cavity of the housing 10 is formed at the groove 2021. Since the explosion-proof valve is integrally formed with the cover plate 201 by stamping, there is no need to separately assemble and weld the explosion-proof sheet. Therefore, the cover plate 201 does not need to be relatively thick due to the feasibility of assembling and welding with the explosion-proof sheet. In typical designs, this method of welding the explosion-proof sheet usually requires the cover plate 201 to be at least 1.5mm thick to ensure good welding of the explosion-proof sheet to the cover plate 201. Therefore, since there is no need to weld the explosion-proof sheet to the cover plate 201, this solution uses a cover plate 201 integrally formed by stamping. It can be formed by stamping thinner sheets or plates, and can be formed by integral stamping of stainless steel sheets or plates with a thickness of 0.15mm to 0.35mm. For example, it can be formed by integral stamping of stainless steel sheets or plates with a thickness of 0.15mm, 0.2mm, 0.25mm or 0.35mm. In this solution, the cover plate 201 is preferably made of 0.2mm stainless steel sheet or plate. Therefore, due to its thinner thickness, the cover plate 201 of the integral explosion-proof valve is easier to stamp and form, the process is simpler, the production efficiency is higher, and the yield rate is higher.Thus, since the residual thickness at the explosion-proof notch 2022 is smaller than the thickness at other locations of the cover plate 201 at the sink 2021, when the cover plate 201 is welded and fixed to the shell 10, when the pressure of the high-pressure gas generated in the shell 10, which is sealed at both ends, reaches the preset value, it will first crack at the notch on the surface of the sink 2021 to release pressure, preventing the gas pressure in the shell 10 from rising continuously and causing a more severe explosion of the entire shell 10, thus achieving the purpose of pressure relief and explosion prevention.

[0067] Understandably, in this application, the explosion-proof notch 2022 can also be optionally provided on the surface of the housing 10, that is, the explosion-proof notch 2022 can also be provided on the outer wall or inner wall of the housing 10 to form an explosion-proof valve structure integral with the housing.

[0068] As an improvement to this embodiment, referring to Figures 23 to 25, the residual thickness of the explosion-proof marking 2022 gradually increases or decreases from one end of the groove 2021 to the opposite end. Referring to Figure 18, which is a schematic diagram of a mold for stamping the explosion-proof marking 2022 onto the surface of the groove 2021, in which the protrusion height of the protrusion 301 used to stamp the explosion-proof marking 2022 increases or decreases from one end of the stamping head 30 to the opposite end. As the thickness of the explosion-proof markings 2022 pressed onto the surface of the groove 2021 by the stamping head 30 gradually decreases or increases, the residual thickness of these markings gradually increases or decreases from one end of the groove 2021 to the opposite end. In this embodiment, the residual thickness of the explosion-proof markings 2022 gradually increases or decreases along the length of the groove 2021. It can be understood that in other feasible embodiments, the residual thickness of the explosion-proof markings 2022 may also gradually increase or decrease along the width of the groove 2021. The residual thickness of the thinner end of the explosion-proof groove 2022 can be set to 0.07mm to 0.09mm, and the residual thickness of the thicker end of the explosion-proof groove 2022 can be set to 0.12mm to 0.14mm. Preferably, when the thickness of the cover plate 201 is 0.2mm, the residual thickness of the thinner end of the explosion-proof groove 2022 is set to 0.08mm, and the residual thickness of the thicker end of the explosion-proof groove 2022 is set to 0.13mm. It can be understood that when the thickness of the cover plate 201 decreases, the residual thickness of the thinner end and the residual thickness of the thicker end of the explosion-proof groove 2022 can be appropriately reduced accordingly. When the thickness of the cover plate 201 increases, the residual thickness of the thinner end and the residual thickness of the thicker end of the explosion-proof groove 2022 can be appropriately increased accordingly. Alternatively, the residual thickness of the thinner end and the residual thickness of the thicker end can be determined according to the parameters of the battery cell inside the housing 10 and the usage environment. Thus, because the residual thickness of the explosion-proof groove 2022 gradually changes, when high pressure is generated inside the housing 10, each time a burst occurs at the settling tank 2021, the cracking begins at the point where the residual thickness of the explosion-proof groove 2022 is the smallest, and then gradually extends towards the end with the thicker residual thickness. The bursting pressure relief is relatively stable. However, if the residual thickness of the explosion-proof groove 2022 is set to be equal and unchanged, the starting point of the cracking of the explosion-proof groove 2022 when the housing 10 bursts and releases pressure is unpredictable, or the entire explosion-proof groove 2022 may burst simultaneously, causing the cover plate 201 in the settling tank 2021 to splash off and detach from the housing 10. In comparison, the variable residual thickness of the explosion-proof groove 2022 in this solution makes the bursting stability and controllability stronger.Understandably, with the residual thickness of the explosion-proof notch 2022 gradually changing, the trajectory of the explosion-proof notch 2022 can also be an unclosed curved segment. In this case, the residual thickness at the thicker end of the explosion-proof notch 2022 is equal to the thickness of the cover plate 201. In this configuration, when high pressure is generated inside the housing 10, each time a burst occurs at the settling tank 2021 to release pressure, the crack will start from the position where the residual thickness of the explosion-proof notch 2022 is the smallest, and then gradually extend towards the thicker end of the explosion-proof notch 2022. Since the thickness of the thicker end of the residual thickness of the explosion-proof groove 2022 is the same as the thickness of the cover plate 201, the thicker end of the residual thickness of the explosion-proof groove 2022 with an unclosed trajectory is thicker than that of the explosion-proof groove 2022 with a closed trajectory. Therefore, the phenomenon that the entire explosion-proof groove 2022 will completely crack when the shell 10 is burst and depressurized will not occur. This effectively avoids the situation where the cover plate 201 at the sink 2021 of the shell 10 splashes off the cover plate 201 and damages other components when the shell 10 is burst and depressurized.

[0069] In this embodiment, the sealing member 20 further includes a protective film 203 for covering the sink 2021 to prevent debris from entering the sink 2021 and corroding the explosion-proof grooves 2022. As shown in Figures 22-24, a first sink platform 2023 is provided on the cover plate 201 around the outer periphery of the sink 2021. The height of the first sink platform 2023 is higher than the height of the sink 2021. The protective film 203 is pasted on the first sink platform 2023 to cover the entire sink 2021. After the protective film 203 is pasted, the lower surface of the protective film 203 is flush with the upper surface of the first sink platform 2023, and the upper surface of the protective film 203 is not higher than the upper surface of the cover plate 201. As shown in Figure 23, in this embodiment, the bottom wall of the sink 2021 is set as an upwardly convex arc surface, and the highest point of the surface of the sink 2021 is... The surface of the sink 2021 is not higher than the plane where the first sink platform 2023 is located. Preferably, the highest point of the surface of the sink 2021 is flush with the lower surface of the protective film 203. The bottom wall of the sink 2021 is set as an upwardly convex arc surface, which can increase the area of ​​pressure acting on the bottom surface of the sink 2021 when high pressure is generated inside the shell 10. This makes it easier for the cover plate 201 at the sink 2021 to break through the explosion-proof groove 2022 and release pressure. At the same time, the upwardly convex bottom wall of the sink 2021 can support the protective film 203 from below, preventing the protective film 203 from being easily broken due to accidental squeezing during transportation and use after the shell 10 is installed. In this way, the protective film 203 can effectively prevent debris such as dust and liquid from entering the sink 2021 and corroding the explosion-proof groove 2022.

[0070] The closure 20 in this embodiment also includes a steel pressure plate 204 for strengthening the cover plate 201 to improve the deformation resistance of the closure 20, as shown in Figures 23 and 24. In this embodiment, the steel pressure plate 204 is pasted on the lower surface of the cover plate 201. The length and width of the steel pressure plate 204 are both smaller than the length and width of the cover plate 201. The middle part of the steel pressure plate 204 has a mounting hole 2042 that cooperates with the sink 2021. The mounting hole 2042 is a through hole, so that the pressure generated inside the housing 10 can be directly applied to the bottom wall of the sink 2021. The upper surface of the steel pressure plate 204 is provided with a second sink 2041 that cooperates with the first sink 2023. When the steel pressure plate 204 is attached to the lower surface of the cover plate 201, the lower surface of the cover plate 201 is attached to the upper surface of the steel pressure plate 204, and the lower surface of the first sink 2023 is attached to the upper surface of the second sink 2041. The steel pressure plate 204 has a thickness of 0.5mm to 0.7mm. Preferably, the steel pressure plate 204 is integrally stamped from a 0.6mm thick stainless steel sheet. With the reinforcing effect of the steel pressure plate 204, the thickness of the cover plate 201 can be as thin as possible, such as 0.15mm, while meeting the required strength of the closure 20. This makes the stamping and forming of the cover plate 201 easier and the yield rate higher. In this embodiment, after the steel pressure plate 204 is attached to the lower surface of the cover plate 201, the lowest point of the sink 2021 is not lower than the plane where the bottom surface of the steel pressure plate 204 is located, to prevent the sink 2021 from being squeezed by the battery cell inside the housing 10, which would cause the explosion-proof groove 2022 to crack, thus ensuring explosion stability.

[0071] Referring to Figures 23 and 24, in this embodiment, the four periphery of the cover plate 201 are formed with downward-facing flanges 205a. The outer wall of the flange 205a is adapted to the inner wall of the housing 10. The height of the flange 205a is less than the thickness of the steel pressure plate 204 and the cover plate 201 stacked together. In this way, the lower end of the flange 205a will not extend downward beyond the lower surface of the steel pressure plate 204 below the cover plate 201, and will not interfere with components such as the battery cell installed in the housing 10. Due to the setting of the flange 205a, the edge of the cover plate 201 has a certain degree of elasticity. When the outer wall of the cover plate 201 is fitted onto the upper port of the housing 10 by the cooperation of the inner wall of the housing 10, the cover plate 201 is more easily assembled onto the upper port of the housing 10. In this embodiment, after the cover plate 201 is assembled onto the upper port of the housing 10, the insertion depth of the flange 205a into the housing is 0.25mm to 0.45mm (the insertion depth of the flange 205a is defined as the distance between the lower end face of the flange 205a and the upper end face of the housing 10). Preferably, the insertion depth of the flange 205a into the housing is 0.3mm. Of course, the insertion depth of the flange 205a into the housing can be reasonably adjusted according to the specifications of the product. In this embodiment, when the cover plate 201 is assembled onto the upper port of the housing 10 to close the upper port of the housing 10, the upper surface of the cover plate 201 is 0.15mm to 0.4mm higher than the upper end face of the housing 10. For example, it can be 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm or 0.4mm. Preferably, the upper surface of the cover plate 201 is 0.3mm higher than the upper end face of the housing 10, so that the upper surface of the cover plate 201 and the upper end face of the housing 10 form a welding step that facilitates welding the cover plate 201 and the housing 10 together. Thus, when the cover plate 201 and the housing 10 are melted and welded together by laser welding at the welding step, a molten pool 50a is formed at the welding step to fill the welding step. During welding, under the blowing state of the protective gas, the molten pool 50a is full in shape and naturally forms a rounded corner state, resulting in a better welding effect.

[0072] Example 3-2

[0073] Referring to Figures 23 and 26, in this embodiment, the four periphery of the cover plate 201 are formed with upward-opening U-shaped flanges 205b. The outer wall of the U-shaped flange 205b is adapted to the inner wall of the housing 10. The lower end face of the U-shaped flange 205b is located above the plane containing the lower surface of the steel pressure plate 204, or the lower end face of the U-shaped flange 205b is flush with the lower surface of the steel pressure plate 204. In this way, the lower end of the U-shaped flange 205b will not extend downward beyond the lower surface of the steel pressure plate 204 below the cover plate 201, and will not interfere with components such as the battery cell installed in the housing 10. The upper end face of the U-shaped flange 205b is flush with the upper end face of the cover plate 201 or located below the plane containing the upper end face of the cover plate 201. Preferably, the upper end face of the U-shaped flange 205b is... In the space below the plane where the upper end face of the cover plate 201 is located, the U-shaped flange 205b provides a certain degree of elasticity to the edge of the cover plate 201. When the outer wall of the U-shaped flange 205b is fitted with the inner wall of the housing 10 to cover the upper port of the housing 10, the cover plate 201 is more easily assembled onto the upper port of the housing 10. In this embodiment, after the cover plate 201 is assembled onto the upper port of the housing 10, the insertion depth of the U-shaped flange 205b into the housing is 0.25mm to 0.45mm (the insertion depth of the U-shaped flange 205b is defined as the distance between the lower end face of the U-shaped flange 205b and the upper end face of the housing 10). Preferably, the insertion depth of the U-shaped flange 205b into the housing is 0.3mm. Of course, the insertion depth of the U-shaped flange 205b into the housing can be reasonably adjusted according to the product specifications. In this embodiment, when the cover plate 201 is assembled to the upper port of the housing 10 to close the upper port of the housing 10, the upper end surface of the U-shaped flange 205b is 0.15mm to 0.4mm higher than the upper end surface of the housing 10. For example, it can be 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm or 0.4mm. Preferably, the upper end surface of the U-shaped flange 205b is 0.2mm higher than the upper end surface of the housing 10, so that the upper surface of the cover plate 201 and the upper end surface of the housing 10 form a welding step that facilitates welding the cover plate 201 and the housing 10 together. Thus, when the cover plate 201 and the housing 10 are melted and welded together by laser welding at the welding step, a molten pool 50b is formed at the welding step to fill the welding step. During welding, under the blowing state of the protective gas, the molten pool 50b is full in shape and naturally forms a rounded corner state, resulting in a better welding effect.

[0074] Example 3-3

[0075] Referring to Figures 23 and 27, in this embodiment, the four periphery of the cover plate 201 are formed with upward-opening U-shaped flanges 205c. The outer wall of the U-shaped flange 205c is adapted to the inner wall of the housing 10. The lower end face of the U-shaped flange 205c is located above the plane containing the lower surface of the steel pressure plate 204, or the lower end face of the U-shaped flange 205c is flush with the lower surface of the steel pressure plate 204. In this way, the lower end of the U-shaped flange 205c will not extend downward beyond the lower surface of the steel pressure plate 204 below the cover plate 201, and will not interfere with components such as battery cells installed in the housing 10. The upper end face of the U-shaped flange 205c is flush with the upper end face of the cover plate 201 or located below the plane containing the upper end face of the cover plate 201. Preferably, the upper end face of the U-shaped flange 205c is... The space below the plane containing the upper end face of the cover plate 201 is provided by the U-shaped flange 205c, which gives the edge of the cover plate 201 a certain degree of elasticity. When the outer wall of the U-shaped flange 205c is fitted with the inner wall of the housing 10 to cover the upper port of the housing 10, the cover plate 201 is more easily assembled onto the upper port of the housing 10. In this embodiment, after the cover plate 201 is assembled onto the upper port of the housing 10, the insertion depth of the U-shaped flange 205c into the housing is 0.4mm to 0.6mm (the insertion depth of the U-shaped flange 205c is defined as the distance between the lower end face of the U-shaped flange and the upper end face of the housing 10). Preferably, the insertion depth of the U-shaped flange 205c into the housing is 0.5mm. Of course, the insertion depth of the U-shaped flange 205c into the housing can be reasonably adjusted according to the product specifications. In this embodiment, when the cover plate 201 is assembled onto the upper port of the housing 10 to close the upper port of the housing 10, the upper end face of the U-shaped flange 205c is flush with the upper end face of the housing 10. When laser welding is used, welding is performed at the gap between the housing 10 and the U-shaped flange 205c, and a molten pool 50c is formed at the gap between the upper end face of the housing 10 and the upper end face of the U-shaped flange 205c.

[0076] Examples 3-4

[0077] Referring to Figures 23 and 28, in this embodiment, the four periphery of the cover plate 201 are formed with upward-opening U-shaped flanges 205d. The outer wall of the U-shaped flange 205d is adapted to the inner wall of the housing 10. The lower end face of the U-shaped flange 205d is located above the plane containing the lower surface of the steel pressure plate 204, or the lower end face of the U-shaped flange 205d is flush with the lower surface of the steel pressure plate 204. In this way, the lower end of the U-shaped flange 205d will not extend downward beyond the lower surface of the steel pressure plate 204 below the cover plate 201, and will not interfere with components such as the battery cell installed in the housing 10. The upper surface of the U-shaped flange 205d is flush with the upper surface of the cover plate 201 or located in the space below the plane containing the upper surface of the cover plate 201. Preferably, the upper surface of the U-shaped flange is located in the space below the plane containing the upper surface of the cover plate 201. The upper surface of the U-shaped flange 205d is provided with an overlap 206 extending horizontally. In this embodiment, when the cover plate 201 is assembled to the upper port of the housing 10 to close the upper port of the housing 10, the lower surface of the overlap 206 is in contact with the upper surface of the housing 10, and the outer peripheral surface of the overlap 206 is flush with the outer wall of the housing 10. When laser welding is used, welding is performed at the gap between the housing 10 and the overlap 206, forming a molten pool 50d at the gap between the upper outer wall of the housing 10 and the outer peripheral surface of the overlap 206.

Claims

1. A steel enclosure comprising a housing having at least one open end and a bottom cover plate closing the open end of the housing, the periphery of the bottom cover plate fitting the interior cavity of the housing, characterized in that: A space for accommodating molten welding material is provided at the position between the periphery of the bottom cover plate and the shell.

2. The steel casing according to claim 1, characterized in that: The upper surface of the bottom cover plate is 0.2mm to 0.4mm higher than the upper end surface of the shell, and the upper end surface of the shell and the outer peripheral surface of the bottom cover plate enclose the retention space.

3. The steel casing according to claim 1, characterized in that: The upper surface of the bottom cover plate has four perimeters with a first chamfer, which, together with the upper inner wall of the shell, forms the retention space; the first chamfer is a straight chamfer, the vertical distance of which is 0.15mm to 0.3mm, and the horizontal distance of which is 0.1mm to 0.2mm; or The first chamfer is a first round chamfer, and the radius R1 of the first round chamfer is 0.15mm to 0.3mm.

4. The steel casing according to claim 1, characterized in that: The shell is a thin-walled cylinder made of stainless steel sheet with a thickness of 0.15mm to 0.3mm.

5. The steel casing according to claim 1, characterized in that: The bottom cover plate is made of stainless steel sheet with a thickness of 0.4mm to 2.0mm. The bottom surface of the bottom cover plate has a second chamfer on all four sides. The second chamfer is a second round chamfer with a radius R2 of 0.1mm to 0.5mm.

6. An explosion-proof steel shell, comprising a shell open at at least one end and a cover plate sealing the open end of the shell, characterized in that: An explosion-proof structure is integrally formed on the surface of the cover plate or the shell, and a flange structure is formed on the four periphery of the cover plate, the outer wall of the flange structure being adapted to the inner wall of the shell.

7. The explosion-proof steel shell according to claim 6, characterized in that: The explosion-proof structure includes explosion-proof grooves provided on the surface of the cover plate or the housing. The residual thickness of the explosion-proof grooves gradually increases or decreases from one end to the opposite end. The residual thickness at the thinner end of the explosion-proof grooves is 0.07 mm to 0.09 mm, and the residual thickness at the thicker end of the explosion-proof grooves is 0.12 mm to 0.14 mm.

8. The explosion-proof steel shell according to claim 7, characterized in that: The cover plate is integrally stamped from a stainless steel sheet with a thickness of 0.15mm to 0.35mm, and the housing is made of a stainless steel sheet with a thickness of 0.15mm to 0.25mm. The cover plate and the housing are sealed and welded together.

9. The explosion-proof steel shell according to claim 6, characterized in that: The flange structure includes a downward flange formed along the four periphery of the cover plate. The outer wall of the flange is adapted to the inner wall of the housing. The height of the flange is 0.5mm to 0.7mm. The upper surface of the cover plate is 0.2mm to 0.4mm higher than the upper end face of the housing to form a welding step between the upper end face of the housing and the upper surface of the cover plate.

10. The explosion-proof steel shell according to claim 6, characterized in that: The flange structure includes an upward-opening U-shaped flange formed along the four perimeter of the cover plate. The outer wall of the U-shaped flange is adapted to the inner wall of the shell. The height of the U-shaped flange is 0.6mm to 1.0mm. The upper end face of the U-shaped flange is 0.15mm to 0.4mm higher than the upper end face of the shell to form a welding step between the upper end face of the shell and the upper surface of the cover plate.

11. The explosion-proof steel shell according to claim 6, characterized in that: The flange structure includes an upward-opening U-shaped flange formed along the four perimeter of the cover plate. The outer wall of the U-shaped flange is adapted to the inner wall of the shell. The height of the U-shaped flange is 0.6mm to 1.0mm, and the upper end face of the U-shaped flange is flush with the upper end face of the shell.

12. The explosion-proof steel shell according to claim 6, characterized in that: The flange structure includes a U-shaped flange with an upward opening formed along the four periphery of the cover plate. The outer wall of the U-shaped flange is adapted to the inner wall of the shell. The height of the U-shaped flange is 0.6mm to 1.0mm. The upper end face of the U-shaped flange is provided with an overlap extending in the horizontal direction. The lower surface of the overlap fits against the upper end face of the shell, and the outer periphery of the overlap is flush with the outer wall of the shell.

13. A steel shell assembly, comprising a shell open at at least one end and a closure sealing the open end of the shell, characterized in that: The closure includes a cover plate adapted to the open end of the housing. Explosion-proof grooves are provided on the surface of the cover plate or the surface of the housing. The residual thickness of the explosion-proof grooves gradually increases or decreases from one end of the explosion-proof groove to the opposite end.

14. The steel shell assembly according to claim 13, characterized in that: The cover plate is provided with a pressure relief section, which includes a groove formed on the cover plate, and the explosion-proof groove is provided on the surface of the groove.

15. The steel shell assembly according to claim 13, characterized in that: The residual thickness of the thinner end of the explosion-proof groove is 0.07mm to 0.09mm, and the residual thickness of the thicker end of the explosion-proof groove is 0.12mm to 0.14mm.

16. The steel shell assembly according to claim 14, characterized in that: A first sinking platform is provided on the cover plate around the outer periphery of the sinking trough. The height of the first sinking platform is higher than the height of the sinking trough. The first sinking platform is used to assemble the protective film.

17. The steel shell assembly according to claim 16, characterized in that: The closure also includes a steel pressure plate attached to the bottom surface of the cover plate. The steel pressure plate is integrally formed by stamping stainless steel sheet with a thickness of 0.5mm to 0.7mm. The steel pressure plate is provided with a second sinking platform that cooperates with the first sinking platform. The steel pressure plate is provided with mounting holes that cooperate with the sinking trough.

18. The steel shell assembly according to claim 13, characterized in that: The cover plate is integrally stamped from a stainless steel sheet with a thickness of 0.15mm to 0.35mm, and the shell is formed by bending and welding from a stainless steel sheet with a thickness of 0.15mm to 0.25mm. The cover plate is welded and fixed to the shell.

19. The steel shell assembly according to any one of claims 13 to 18, characterized in that: The cover plate has downward-facing flanges along its four perimeters, the outer walls of which are adapted to the inner walls of the housing. The upper surface of the cover plate is 0.15mm to 0.4mm higher than the upper end surface of the housing; or The cover plate has U-shaped flanges with upward openings on all four sides. The outer wall of the U-shaped flange is adapted to the inner wall of the shell. The upper end face of the U-shaped flange is flush with or higher than the upper end face of the shell. Preferably, the upper end face of the U-shaped flange is 0.15mm to 0.4mm higher than the upper end face of the shell.

20. The steel shell assembly according to any one of claims 13 to 18, characterized in that: The cover plate has U-shaped flanges with upward openings on all four sides. The outer wall of the U-shaped flange is adapted to the inner wall of the shell. The upper end face of the U-shaped flange is provided with an overlap extending in the horizontal direction. The lower surface of the overlap fits against the upper end face of the shell, and the outer peripheral surface of the overlap is flush with the outer wall of the shell.

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