Battery shell structure with variable wall thickness and cylindrical battery

Abstract

The utility model discloses a battery shell structure with variable wall thickness and a cylindrical battery, the battery shell structure comprises a shell with at least one open end, and a cover plate is matched at the open part of the shell; the side wall at the opening of the shell is thickened inwards to form a first thick wall area, and the length of the first thick wall area in the axial direction of the shell is larger than the thickness of the cover plate; the diameter of the cover plate is matched with the inner diameter of the first thick-wall area, and the cover plate is welded to the first thick-wall area in a matched mode. The utility model has the advantages of reasonable structural design, difficult burn-through deformation, and the like, and is favorable for improving the production qualification rate.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a battery casing structure with variable wall thickness and a cylindrical battery. Background Technology

[0002] Currently, with the rapid development of the new energy industry, society's requirements for the energy density, safety performance, and fast charging performance of lithium-ion batteries are further increasing. Large cylindrical batteries, as a widely accepted solution, are ushering in a broad market space. Large cylindrical batteries mainly consist of a casing and a wound core assembly housed within the casing. The wound core assembly is inserted through the open end of the casing and then sealed by welding with a cover plate. However, existing casings have a uniform wall thickness and are relatively thin overall. When welding the cover plate to the casing, the thinner sheet material is prone to deformation or burn-through, easily resulting in pinholes and air leaks, leading to poor sealing and affecting the assembly qualification rate. Utility Model Content

[0003] In view of the shortcomings of the prior art, the technical problem to be solved by this utility model is: how to provide a variable wall thickness battery casing structure and cylindrical battery with reasonable structural design, which is not easy to burn through and deform, and which is conducive to improving the production qualification rate.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A variable wall thickness battery casing structure includes a casing with an opening at at least one end, and a cover plate fitting at the opening of the casing; the sidewall of the casing opening is thickened inward to form a first thick wall region, the length of the first thick wall region in the axial direction of the casing is greater than the thickness of the cover plate; the diameter of the cover plate matches the inner diameter of the first thick wall region and is welded to the first thick wall region.

[0006] In the above structure, the opening of the shell thickens inward to form the first thick wall area, which makes it less likely for the cover plate to be burned through or deformed when welding to the opening of the shell, thereby reducing the chance of air leakage and pinholes and improving the pass rate.

[0007] Furthermore, the housing has an inwardly thickened, annular second thick-walled region. At least two second thick-walled regions are spaced apart along the axial direction of the housing. A thin-walled region is formed between each second thick-walled region and an adjacent first or second thick-walled region.

[0008] In this way, the second thick-walled area can provide better support strength to the casing to prevent external impacts from affecting the inside of the battery; while the thin-walled area, due to its thinner wall thickness, has better ductility and can be easily expanded when a failure occurs inside the battery, avoiding a sharp increase in internal pressure that could cause an explosion and reducing the risk of battery explosion.

[0009] Furthermore, the thickness of the first thick-walled region and the second thick-walled region is 0.4 to 0.6 mm; the thickness of the thin-walled region is 0.2 to 0.3 mm.

[0010] Furthermore, the inner diameters of the first thick-walled region and the second thick-walled region gradually increase towards the adjacent thin-walled region to form a transition zone.

[0011] In this way, stress concentration between the thin-walled and thick-walled regions can be avoided through the transition zone, which can both ensure the structural strength of the battery and improve its safety in the event of battery failure.

[0012] Furthermore, the axial length of the second thick-walled region and the thin-walled region is 1 to 2 cm.

[0013] Furthermore, the outer side of the cover plate has a flange that protrudes radially outward, and the outer diameter of the flange is consistent with the outer diameter of the housing.

[0014] Furthermore, the cover plate has a coaxial mounting hole in the middle, and an electrode post is insulatedly riveted to the mounting hole; the electrode post has a through-hole in the middle, and a sealing pin is fitted on the injection hole.

[0015] Furthermore, an insulating pad with a sealing ring is provided between the pole and the cover plate; the inner side of the cover plate has an annular insulating pad, the inner ring of which is insulatedly connected to the sealing ring and riveted between the pole and the cover plate, and the outer diameter of the insulating pad matches the inner diameter of the housing.

[0016] Furthermore, the outer end of the injection hole has an annular groove that expands radially outward, and the thickness of the sealing pin matches the depth of the annular groove.

[0017] A cylindrical battery includes a battery casing structure with variable wall thickness as described above.

[0018] In summary, this utility model has the advantages of reasonable structural design, resistance to burn-through and deformation, and improved production qualification rate. Attached Figure Description

[0019] Figure 1 This is a cross-sectional structural diagram of an embodiment.

[0020] Figure 2 for Figure 1 A partial structural diagram.

[0021] Figure 3 This is a schematic diagram of the bottom of the shell. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments.

[0023] In practical implementation: such as Figure 1 and Figure 2 As shown, a variable wall thickness battery casing structure includes a casing 1 with an open end, a cover plate 2 fitting at the open end of the casing 1, and C-shaped explosion-proof grooves on the bottom of the casing 1. Figure 3 As shown; the sidewall at the opening of the housing 1 thickens inward to form a first thick-walled region 11, the length of the first thick-walled region 11 in the axial direction of the housing 1 is greater than the thickness of the cover plate 2; the diameter of the cover plate 2 matches the inner diameter of the first thick-walled region 11 and is welded to the first thick-walled region 11. In this embodiment, the outer side of the cover plate 2 has a flange 21 that protrudes radially outward, the outer diameter of the flange 21 is the same as the outer diameter of the housing 1, and it covers the end of the housing 1.

[0024] The housing 1 has an inwardly thickened, annular second thick-walled region 12. At least two of these second thick-walled regions 12 are spaced apart along the axial direction of the housing 1. A thin-walled region 13 is formed between each second thick-walled region 12 and an adjacent first thick-walled region 11 or second thick-walled region 12. The inner diameters of the first thick-walled region 11 and the second thick-walled region 12 gradually increase towards the adjacent thin-walled region 13, forming a transition region 14. In this embodiment, the thickness of the first thick-walled region 11 and the second thick-walled region 12 is 0.5 mm; the thickness of the thin-walled region 13 is 0.3 mm; and the axial length of the second thick-walled region 12 and the thin-walled region 13 is 1–2 cm.

[0025] The cover plate 2 has a coaxial mounting hole in its center, and an electrode post 3 is insulatedly riveted to the mounting hole. The electrode post 3 has a through-hole 31 in its center, and a sealing pin 32 fits onto the injection hole 31. The outer end of the injection hole 31 has an annular groove that expands radially outward, and the thickness of the sealing pin 32 matches the depth of the annular groove. A sealing ring 22 is provided as an insulating pad between the electrode post 3 and the cover plate 2. The inner side of the cover plate 2 has an annular insulating pad 23, the inner ring of which is insulatedly connected to the sealing ring 22 and riveted between the electrode post 3 and the cover plate 2. The outer diameter of the insulating pad 23 matches the inner diameter of the housing 1.

[0026] In this embodiment, the casing 1 has a first thick-walled region, a thin-walled region, and a second thick-walled region spaced apart. The thick-walled region has a larger thickness, which can increase the structural strength of the battery and prevent external impacts from affecting the battery's interior. The thin-walled region has a smaller thickness, which can easily expand when the battery fails internally, increasing the internal space of the battery and preventing a rapid increase in pressure that could lead to an explosion, thus reducing the risk of explosion. If the internal failure state of the battery continues and the pressure continues to increase, the explosion-proof grooves on the casing will be broken through, releasing the pressure.

[0027] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A battery casing structure with variable wall thickness, characterized in that, The shell (1) includes a shell (1) with an opening at at least one end, and a cover plate (2) is fitted at the opening of the shell (1); the side wall of the shell (1) at the opening is thickened inward to form a first thick wall region (11), and the length of the first thick wall region (11) in the axial direction of the shell (1) is greater than the thickness of the cover plate (2); the diameter of the cover plate (2) matches the inner diameter of the first thick wall region (11) and is welded to the first thick wall region (11).

2. The variable wall thickness battery casing structure as described in claim 1, characterized in that, The housing (1) has an inwardly thickened second thick-walled region (12) forming an annular shape. At least two second thick-walled regions (12) are provided at intervals along the axial direction of the housing (1). A thin-walled region (13) is formed between any second thick-walled region (12) and the adjacent first thick-walled region (11) or second thick-walled region (12).

3. The variable wall thickness battery casing structure as described in claim 2, characterized in that, The thickness of the first thick-walled region (11) and the second thick-walled region (12) is 0.4 to 0.6 mm; the thickness of the thin-walled region (13) is 0.2 to 0.3 mm.

4. The variable wall thickness battery casing structure as described in claim 2, characterized in that, The inner diameters of the first thick-walled region (11) and the second thick-walled region (12) gradually increase toward the adjacent thin-walled region (13) to form a transition region (14).

5. The variable wall thickness battery casing structure as described in claim 2, characterized in that, The axial length of the second thick-walled region (12) and thin-walled region (13) is 1 to 2 cm.

6. The variable wall thickness battery casing structure as described in claim 1, characterized in that, The outer side of the cover plate (2) has a flange (21) that protrudes radially outward, and the outer diameter of the flange (21) is the same as the outer diameter of the shell (1).

7. The variable wall thickness battery casing structure as described in claim 1, characterized in that, The cover plate (2) has a coaxial mounting hole in the middle, and an electrode post (3) is insulatedly riveted to the mounting hole; the electrode post (3) has a through injection hole (31) in the middle, and a sealing nail (32) is fitted on the injection hole (31).

8. The variable wall thickness battery casing structure as described in claim 7, characterized in that, An insulating pad with a sealing ring (22) is provided between the pole post (3) and the cover plate (2); the inner side of the cover plate (2) has an annular insulating pad (23), the inner ring of the insulating pad (23) is insulatedly connected to the sealing ring (22) and riveted between the pole post (3) and the cover plate (2), and the outer diameter of the insulating pad (23) matches the inner diameter of the housing (1).

9. The variable wall thickness battery casing structure as described in claim 7, characterized in that, The outer end of the injection hole (31) has an annular groove that expands radially outward, and the thickness of the sealing pin (32) matches the depth of the annular groove.

10. A cylindrical battery, characterized in that, Includes the variable wall thickness battery casing structure as described in any one of claims 1 to 9.

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