Battery steel shell, battery cell and power device

Abstract

The utility model relates to the technical field of batteries, and discloses a battery steel shell, a battery cell and a power device. The battery steel shell comprises a shell body and a bottom plate, wherein the shell body is of a cylindrical structure with a cavity; the bottom plate is matched with the shell, the bottom plate is arranged at one end of the shell, and the other end of the shell is open; the bottom plate is provided with a rough area and a pressure relief structure. According to the utility model, the rough area is arranged on the bottom plate of the battery steel shell, so that the contact resistance during welding can be increased through the rough area, the negative tab can be more easily welded on the bottom plate of the battery steel shell, the welding strength is increased, the welding is firm, and insufficient welding or infirm spot welding is avoided; and therefore, the cylindrical battery meets the requirement on the welding quality in the welding process. The bottom plate of the battery steel shell is provided with the pressure relief structure, so that when the battery is in thermal runaway, the explosion-proof valve on the cover plate at the top of the battery cell is used for relieving pressure, and the pressure relief structure is also used for exhausting and relieving pressure, so that the safety performance of the battery is improved, and the finished battery cell meets the safety requirement.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery steel shell, a battery core and a power device. Background Art

[0002] Cylindrical batteries are highly standardized and have the most mature technology. Since 18650 cylindrical batteries have a long history, they have a high market penetration rate, and 21700 cylindrical batteries promote the rapid application of green power energy. Cylindrical batteries are widely used in different scenarios such as consumer electronics, power tools, energy storage market, light power, electric vehicles, etc.

[0003] At present, the battery cell shell is usually made of steel shell with a normal straight cylindrical structure. During the manufacturing process, the pole ear of the pole group needs to be welded to the bottom of the steel shell. During the welding process, it is easy to have a cold weld, which affects the performance of subsequent products and causes the battery to be scrapped due to poor performance. In addition, when the product fails to work safely, the explosion-proof valve of the battery does not meet the pressure relief requirements, making the battery lose its safety guarantee and ultimately posing a safety hazard.

[0004] Such a battery cell shell cannot meet the requirements of reducing the defective rate during welding and achieving a higher safety level. Utility Model Content

[0005] In view of this, the utility model provides a battery steel shell, a battery cell and a power device to solve the problem that the current battery steel shell structure cannot meet the requirements of reducing the defective rate in the welding process and meeting the higher level of safety requirements.

[0006] In the first aspect, the utility model provides a battery steel shell, including a shell and a bottom plate, the shell is a cylindrical structure with a cavity; the bottom plate matches the shell, the bottom plate is arranged at one end of the shell, and the other end of the shell is open; the bottom plate is provided with a rough area and a pressure relief structure.

[0007] Beneficial effects: The bottom plate of the battery steel shell is provided with a rough area, so that the rough area can increase the contact resistance during welding, making it easier to weld the negative electrode ear to the bottom plate of the battery steel shell, increasing the welding strength, making the welding firm, avoiding the occurrence of cold welding or loose spot welding, so that the cylindrical battery meets the requirements for welding quality during the welding process. Since the bottom plate of the battery steel shell is provided with a pressure relief structure, when the battery has thermal runaway, in addition to relieving pressure through the explosion-proof valve on the top cover of the battery cell, the pressure relief structure can also be used to exhaust and relieve pressure, thereby improving the safety performance of the battery and making the finished battery cell meet the safety requirements. Since the battery steel shell provided by the utility model is still a cylindrical structure as a whole, it does not affect the appearance of the battery steel shell, does not damage the appearance of the steel shell, conforms to the mass production of the production process, and meets the quality requirements of the welding process and the safety requirements of the product.

[0008] In an optional embodiment, the diameter of the rough area is D1, D1 = 4±1 mm, and the thickness of the rough area is T1, T1 = 0.03±0.01 mm.

[0009] Beneficial effect: With this arrangement, the shape of the rough area is adapted to the shape of the bottom plate, which is convenient for processing and positioning. The diameter and thickness of the rough area are controlled within the above range, which can adapt to the size of most cylindrical batteries to improve the welding strength requirements of the bottom of the battery steel shell.

[0010] In an optional embodiment, the pressure relief structure includes a notch, which is arranged on the outside of the rough area, and is a continuous or discontinuous arc, and the total length of the notch occupies a sector angle of not less than 60°.

[0011] Beneficial effect: The pressure relief structure adopts the form of notches, which is easy to process. The notches are set on the outside of the rough area, which is easy to explode when high-pressure gas is generated inside the battery cell, and the explosion area is large, which improves the reliability of battery safety control. The notches can be continuous or intermittent, and the total length of the notches occupies a sector angle greater than or equal to 60°, which can ensure the safety requirement of timely pressure relief when the battery is out of control.

[0012] In an optional embodiment, the diameter of the circle where the notch is located is D2, D2 = 10 ± 1 mm; and / or, the residual thickness of the notch is h, h = 0.08 ± 0.01 mm; and / or, the width of the notch is W, W = 0.1 ± 0.1 mm.

[0013] Beneficial effect: By limiting the diameter, residual thickness and width of the notch, it can be ensured that the notch can normally burst and release pressure when high-pressure gas is generated inside the battery cell.

[0014] In an optional embodiment, the outer diameter of the bottom plate is D3, 21.48 mm ≤ D3 ≤ 21.54 mm; and / or the thickness of the bottom plate excluding the rough area is T2, T2 = 0.3 ± 0.02 mm.

[0015] In an optional embodiment, the bottom plate is provided with a chamfer toward the shell, and the length of the chamfer is L, where L=0.7±0.1 mm.

[0016] Beneficial effect: By limiting the outer diameter of the bottom plate, the thickness of the bottom plate except the rough area, and the length of the chamfer of the bottom plate within the above range, the strength requirement of the battery steel shell can be guaranteed.

[0017] In an optional embodiment, the height of the shell is H, H=74.25±0.05mm; and / or the wall thickness of the shell is T3, 0.19mm≤T3≤0.22mm; and / or the outer diameter of the shell is D4, D4=21.5±0.05mm.

[0018] Beneficial effect: By limiting the height of the shell, the wall thickness of the shell and the outer diameter of the shell within the above-mentioned range, the battery steel shell can meet the application requirements of multiple scenarios.

[0019] In an optional embodiment, the outer diameter of the open end of the shell is D5, D5 = 21.60 ± 0.05 mm, and the wall thickness of the open end of the shell is T4, T4 = 0.25 ± 0.02 mm.

[0020] Advantageous Effects: By limiting the outer diameter of the open end of the shell and the wall thickness of the open end of the shell to the above range, the connection between the cover plate and the shell can be facilitated.

[0021] In the second aspect, the utility model provides a battery core, comprising the battery steel shell described in any one of the above embodiments, as well as a cover plate and an electrode group. The cover plate is arranged at the open end of the battery steel shell; an explosion-proof valve is arranged on the cover plate; and the electrode group is encapsulated in the inner cavity of the battery steel shell by the cover plate.

[0022] Beneficial effect: Since the battery cell includes the above-mentioned battery steel shell, the bottom plate of the battery steel shell is provided with a rough area, so that the rough area can increase the contact resistance during welding, increase the welding strength, make the welding firm, avoid the occurrence of cold welding or spot welding, so that the cylindrical battery meets the requirements for welding quality during the welding process. Since the bottom plate of the battery steel shell is provided with a pressure relief structure, when the battery has thermal runaway, the high-pressure gas inside the battery cell can be discharged and depressurized from the explosion-proof valve on the top cover of the battery cell through the pressure relief structure, and the gas can also be exhausted and depressurized from the pressure relief structure of the bottom plate of the battery steel shell, thereby increasing the insurance capacity, improving the safety performance of the battery, reducing the safety hazards when the battery fails, and making the finished battery cell meet the safety requirements.

[0023] In a third aspect, the utility model provides a power device, comprising a plurality of battery cells, wherein the battery cells include the battery steel shell of any one of the above technical solutions.

[0024] Beneficial effects: Since the power device includes the above-mentioned battery cell, it has all the beneficial effects of the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A cross-sectional view of a battery steel shell according to an embodiment of the utility model;

[0027] Figure 2 for Figure 1 A is a partial enlarged schematic diagram;

[0028] Figure 3 for Figure 1 A partial enlarged schematic diagram of point B in the middle;

[0029] Figure 4 for Figure 1 A bottom view of the battery steel case shown;

[0030] Figure 5 It is a partial cross-sectional view of the notch.

[0031] Description of reference numerals:

[0032] 10. Battery steel shell; 1. Shell; 2. Bottom plate; 21. Chamfer; 3. Rough area; 4. Pressure relief structure; 41. Scratches. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0034] In the battery manufacturing process, the different structures and usage scenarios of battery steel shells lead to differences in the manufacturing capacity and safety requirements of battery cells. Due to differences in process manufacturing methods, the structure and manufacturing of different steel shells have different effects on battery performance and safety, which greatly affects the performance and safety of the final product.

[0035] Currently, cold welding often occurs at the bottom of the battery steel shell during welding with the pole ear of the pole group, resulting in welding defects. At the same time, the product safety performance of the battery needs to be improved. In order to solve the above two technical problems at the same time, the utility model provides a structural design of a battery steel shell, so that the battery cell with the battery steel shell can fully meet the welding quality requirements of the cylindrical battery during the welding process and the safety requirements of the finished battery, which is very instructive for quality process product monitoring and finished product safety reliability.

[0036] Combine the following Figures 1 to 5 , describing an embodiment of the utility model.

[0037] According to an embodiment of the utility model, in a first aspect, a battery steel shell 10 is provided, comprising a shell 1 and a bottom plate 2, wherein the shell 1 is a cylindrical structure with a cavity; the bottom plate 2 matches the shell 1, the bottom plate 2 is arranged at one end of the shell 1, and the other end of the shell 1 is open; the bottom plate 2 is provided with a rough area 3 and a pressure relief structure 4.

[0038] The bottom plate 2 of the battery steel shell 10 is provided with a rough area 3, so that the rough area 3 can increase the contact resistance during welding, making it easier for the negative electrode ear to be welded to the bottom plate 2 of the battery steel shell 10, increasing the welding strength, making the welding firm, avoiding the occurrence of cold welding or spot welding, so that the cylindrical battery meets the requirements for welding quality during the welding process. Since the bottom plate 2 of the battery steel shell 10 is provided with a pressure relief structure 4, when the battery has thermal runaway, in addition to relieving pressure through the explosion-proof valve on the top cover of the battery cell, the pressure relief structure 4 can also be used to exhaust and relieve pressure, thereby improving the safety performance of the battery and making the finished battery cell meet the safety requirements. Since the battery steel shell 10 provided by the utility model is still a cylindrical structure as a whole, it does not affect the appearance of the battery steel shell 10, does not damage the appearance of the steel shell 1, conforms to the mass production of the production process, and meets the quality requirements of the welding process and the safety requirements of the product.

[0039] The shell 1 and the bottom plate 2 of the battery steel shell 10 can be connected by welding or can be integrally formed.

[0040] The following are eight specific experimental cases, see Table 1. Among them, S1 is the area of ​​the rough area, S2 is the area of ​​the welding area, and the verification result is the result of actual welding. Among them, "OK" means that the area of ​​the rough area 3 of the bottom plate 2 is sufficient, and the welding between the bottom plate 2 and the tab is firm, and "NG" means that the area of ​​the rough area 3 of the bottom plate 2 is seriously insufficient, and there is a virtual welding between the bottom plate 2 and the tab.

[0041] Table 1:

[0042]

[0043] As shown in Table 1, the diameter of the rough area is controlled within the range of D1 = 4 ± 1 mm to ensure that there is enough area of ​​the rough area to weld with the tab, so as to increase the welding resistance, thereby increasing the welding strength, ensuring that the welding is firm and stable, and there will be no defects such as displacement and cold welding. At the same time, the diameter of the rough area is controlled within the range of D1 = 4 ± 1 mm, and the specifications of the welding needle are not limited.

[0044] In one embodiment, Figure 3 As shown, the diameter of the rough area 3 is D1, D1 = 4 ± 1 mm, as Figure 2 As shown, the thickness of the rough area 3 is T1, T1 = 0.03 ± 0.01 mm.

[0045] Specifically, the rough area 3 is circular, so that the shape of the rough area 3 is adapted to the shape of the bottom plate 2, which is convenient for processing and positioning. In one embodiment, the rough area 3 is circular, and the rough area 3 is concentrically arranged with the bottom plate 2. The diameter of the rough area 3 is controlled within the range of 4±1mm, and the thickness of the rough area 3 is controlled within the range of 0.03±0.01mm, which can adapt to the size of most cylindrical batteries to improve the welding strength requirements of the bottom of the battery steel shell 10. In one embodiment, the diameter of the rough area 3 is 4mm, and the thickness of the rough area 3 is 0.03mm.

[0046] In one embodiment, the rough area 3 is formed by rolling with a rolling tool.

[0047] By rolling the bottom plate 2 with a rolling mold, a rough area 3 can be formed on the bottom plate 2, which is convenient for processing.

[0048] In one embodiment, the pressure relief structure 4 includes a notch 41 , which is disposed outside the rough area 3 , and is a continuous or discontinuous arc, and the total length of the notch 41 occupies a sector angle of not less than 60°.

[0049] The pressure relief structure 4 is in the form of a notch 41, which is easy to process. The notch 41 is arranged on the outside of the rough area 3, which is easy to explode when high-pressure gas is generated inside the battery cell, and the explosion area is large, which improves the reliability of battery safety control. The notch 41 can be continuous or intermittent, and the sector angle occupied by the total length of the notch 41 is greater than or equal to 60°, which can ensure the safety requirement of timely pressure relief when the battery is out of control. When the notch 41 is intermittent, multiple sections of the notch 41 are evenly spaced around the center of the bottom plate 2. In this way, the reliability of the notch 41 opening the pressure relief can be further improved.

[0050] In one embodiment, Figure 3 As shown, the diameter of the circle where the notch 41 is located is D2, D2 = 10 ± 1mm; and / or, as Figure 4 As shown, the residual thickness of the notch 41 is h, h = 0.08 ± 0.01 mm; and / or Figure 4 As shown, the width of the notch 41 is W, W = 0.1 ± 0.1 mm.

[0051] Specifically, the residual thickness of the notch 41 refers to the residual thickness of the notch 41 area of ​​the bottom plate 2 of the battery steel shell 10 after the notch 41 is set. If the notch 41 is an arc, and the diameter of the notch 41 is too large, it will be closer to the edge of the bottom plate 2; if the diameter of the notch 41 is too small, the notch 41 will be closer to the rough area 3, which is not conducive to processing. If the residual thickness of the notch 41 is too large or the width is too small, it is not conducive to the explosion and pressure relief of the bottom plate 2, and the safety cannot meet the requirements. If the residual thickness of the notch 41 is too small or the width is too large, it will affect the strength of the shell 1, so that the bottom plate 2 will explode in advance before the opening pressure is reached inside the battery cell, causing the battery to fail prematurely and affecting the battery life. By limiting the diameter, residual thickness and width of the notch 41, it can be ensured that the notch 41 explodes and releases pressure normally when high-pressure gas is generated inside the battery cell.

[0052] In one embodiment, the diameter of the notch 41 is 10 mm, the residual thickness of the notch 41 is 0.08 mm, and the width of the notch 41 is 0.1 mm.

[0053] In one embodiment, Figure 2 As shown, the outer diameter of the bottom plate 2 is D3, 21.48mm≤D3≤21.54mm; and / or, as Figure 2 As shown, the thickness of the bottom plate 2 excluding the rough area 3 is T2, where T2 = 0.3 ± 0.02 mm.

[0054] In one embodiment, Figure 2 As shown, the bottom plate 2 is provided with a chamfer 21 facing the housing 1 , and the length of the chamfer 21 is L, where L=0.7±0.1 mm.

[0055] By limiting the outer diameter of the bottom plate 2, the thickness of the bottom plate 2 except the rough area 3, and the length of the chamfer 21 of the bottom plate 2 within the above ranges, the strength requirement of the battery steel case 10 can be ensured.

[0056] In one embodiment, the outer diameter of the bottom plate 2 is 21.5 mm, the thickness of the bottom plate 2 excluding the rough area 3 is 0.3 mm, and the bottom plate 2 is provided with a chamfer 21 toward the housing 1, and the length of the chamfer 21 is 0.7 mm.

[0057] In one embodiment, Figure 1 As shown, the height of the housing 1 is H, H = 74.25 ± 0.05 mm; and / or Figure 2 As shown, the wall thickness of the housing 1 is T3, 0.19 mm ≤ T3 ≤ 0.22 mm; and / or, as Figure 1 As shown, the outer diameter of the housing 1 is D4, D4 = 21.5 ± 0.05 mm.

[0058] By limiting the height of the shell 1 , the wall thickness of the shell 1 , and the outer diameter of the shell 1 within the above-mentioned range, the battery steel shell 10 can meet the application requirements of multiple scenarios.

[0059] In one embodiment, the height of the shell 1 is 74.25 mm, the wall thickness of the shell 1 is 0.20 mm, and the outer diameter of the shell 1 is 21.5 mm.

[0060] In one embodiment, Figure 1 As shown, the outer diameter of the open end of the housing 1 is D5, D5 = 21.60 ± 0.05 mm. Figure 5 As shown, the wall thickness of the open end of the shell 1 is T4, T4 = 0.25 ± 0.02 mm.

[0061] By limiting the outer diameter of the open end of the housing 1 and the wall thickness of the open end of the housing 1 to the above ranges, the connection between the cover plate and the housing 1 can be facilitated.

[0062] In one embodiment, the outer diameter of the open end of the housing 1 is 21.60 mm, and the wall thickness of the open end of the housing 1 is 0.25 mm.

[0063] According to an embodiment of the utility model, in a second aspect, a battery cell is provided, comprising a battery steel shell 10 as described in any one of the above embodiments, a cover plate and a pole group. The cover plate is arranged at the open end of the battery steel shell 10; an explosion-proof valve is arranged on the cover plate; and the pole group is encapsulated in the inner cavity of the battery steel shell 10 by the cover plate.

[0064] Since the battery cell provided in this embodiment includes the battery steel shell 10 in the above embodiment, the bottom plate 2 of the battery steel shell 10 is provided with a rough area 3, so that the rough area 3 can increase the contact resistance during welding, increase the welding strength, make the welding firm, avoid the occurrence of cold welding or spot welding, so that the cylindrical battery meets the requirements for welding quality during the welding process. Since the bottom plate 2 of the battery steel shell 10 is provided with a pressure relief structure 4, when the battery has thermal runaway, the high-pressure gas inside the battery cell can be discharged and depressurized from the explosion-proof valve on the top cover of the battery cell through the pressure relief structure 4, and the gas can also be discharged and depressurized from the pressure relief structure 4 of the bottom plate 2 of the battery steel shell 10, thereby increasing the insurance capacity, improving the safety performance of the battery, reducing the safety hazards when the battery fails, and making the finished battery cell meet the safety requirements.

[0065] According to an embodiment of the utility model, in a third aspect, a power device is provided, comprising a plurality of battery cells, wherein the battery cells comprise a battery steel shell 10 according to any one of the above technical solutions.

[0066] Since the power device provided in this embodiment includes the battery cell of the above embodiment, it has all the beneficial effects of the above battery cell.

[0067] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery steel shell, characterized in that: include: A shell, wherein the shell is a cylindrical structure with a cavity; A bottom plate, the bottom plate matches the shell, the bottom plate is arranged at one end of the shell, and the other end of the shell is open; the bottom plate is provided with a rough area and a pressure relief structure, the rough area is circular and is concentrically arranged with the bottom plate, the pressure relief structure includes a notch, the notch is a continuous or discontinuous arc, the diameter of the circle where the notch is located is D2, D2 = 10 ± 1mm; and / or, the residual thickness of the notch is h, h = 0.08 ± 0.01mm; and / or, the width of the notch is W, W = 0.1 ± 0.1mm.

2. The battery steel shell according to claim 1, characterized in that: The diameter of the rough area is D1, D1=4±1 mm, and the thickness of the rough area is T1, T1=0.03±0.01 mm.

3. The battery steel shell according to claim 1 or 2, characterized in that: The notches are arranged outside the rough area, and the sector angle occupied by the total length of the notches is not less than 60°.

4. The battery steel shell according to claim 1 or 2, characterized in that: The outer diameter of the bottom plate is D3, 21.48 mm ≤ D3 ≤ 21.54 mm; and / or the thickness of the bottom plate excluding the rough area is T2, T2 = 0.3 ± 0.02 mm.

5. The battery steel shell according to claim 1 or 2, characterized in that: The bottom plate is provided with a chamfer toward the shell, and the length of the chamfer is L, where L=0.7±0.1 mm.

6. The battery steel shell according to claim 1 or 2, characterized in that: The height of the shell is H, H=74.25±0.05mm; and / or the wall thickness of the shell is T3, 0.19mm≤T3≤0.22mm; and / or the outer diameter of the shell is D4, D4=21.5±0.05mm.

7. The battery steel shell according to claim 1 or 2, characterized in that: The outer diameter of the open end of the shell is D5, D5 = 21.60 ± 0.05 mm, and the wall thickness of the open end of the shell is T4, T4 = 0.25 ± 0.02 mm.

8. A battery, characterized in that: include: The battery steel shell according to any one of claims 1 to 7; A cover plate, the cover plate being arranged at the open end of the battery steel shell; the cover plate being provided with an explosion-proof valve; The electrode group is encapsulated in the inner cavity of the battery steel shell by the cover plate.

9. A power device, characterized in that: The invention comprises a plurality of battery cells, wherein the battery cells comprise the battery steel shell according to any one of claims 1 to 7.

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