Battery shell and battery assembly

Abstract

The utility model provides a battery shell and a battery assembly. The battery case comprises a case body (1), a cover plate (2) and a nick (3), the cover plate (2) covers the case body (1), and the nick (3) extends in the circumferential direction of the surface of the case body (1) and forms a closed ring. According to the battery shell and the battery assembly provided by the utility model, the closed annular nicks are arranged on the surface of the shell along the circumferential direction, so that the problem that the nick area of an anti-explosion valve is untimely invalid due to the fact that the anti-explosion nicks are arranged on the local part of the shell of the existing battery shell to form a stress concentration area is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technology field, specifically, relate to a battery shell and battery assembly. BACKGROUND

[0002] In the lithium battery technical field, the design and implementation of the explosion-proof valve is one of the key links to ensure the safe operation of the battery. Under abnormal conditions such as overcharge, short circuit, and thermal runaway, a large amount of heat and gas will be generated inside the lithium battery. If these pressures cannot be released in time, the battery may explode, causing serious safety problems. Therefore, the role of the explosion-proof valve is to automatically open when the internal pressure of the battery reaches a certain threshold, releasing the excessive internal pressure and preventing the battery from exploding.

[0003] An explosion-proof valve is usually designed in a lithium battery as a safety protection mechanism. The main role of the explosion-proof valve is to release the excessive pressure by cracking the notch when the internal pressure of the battery exceeds the safety threshold, preventing the battery from exploding. The traditional notch design of the explosion-proof valve is mostly concentrated on the top or specific local area of the aluminum shell. The local setting of the notch will form a stress concentration point, which will bear a large local stress during assembly or use, possibly leading to premature failure of the explosion-proof valve notch area. Once the battery encounters an abnormal situation during use, the prematurely failed explosion-proof valve notch may cause the explosion-proof valve to open late or not release the internal pressure completely after opening, increasing the possibility of a dangerous battery. SUMMARY

[0004] The main purpose of the utility model is to provide a battery shell that can solve the problem of premature failure of the explosion-proof valve notch area caused by setting the explosion-proof notch on the local part of the shell, thereby causing the explosion-proof valve to open late or not release the internal pressure completely after opening, and further increasing the possibility of a dangerous battery.

[0005] To achieve the above purpose, according to one aspect of the utility model, a battery shell is provided, which includes a shell, a cover plate, and a notch. The cover plate is covered on the shell, and the notch extends along the circumferential surface of the shell and forms a closed ring shape.

[0006] Further, an electric core is arranged in the shell, and the notch is arranged on the inner wall of the shell between the cover plate and the electric core.

[0007] Further, the notch is arranged on the outer wall of the shell between the cover plate and the electric core.

[0008] Further, the most side edge of the notch is parallel to the plane where the cover plate is located.

[0009] Further, the first end of the battery shell is provided with a first cover plate, and the shell is provided with a first notch close to the first cover plate.

[0010] Further, the second end of the battery shell is provided with a second cover plate, and the shell is provided with a second score close to the second cover plate.

[0011] Further, the distance between the first score and the first cover plate is 4mm-10mm.

[0012] Further, the distance between the second score and the second cover plate is 4mm-10mm.

[0013] Further, the depth of the first score is 0.2mm-0.3mm.

[0014] Further, the depth of the second score is 0.2mm-0.3mm.

[0015] Further, the distance between the first score and the first cover plate is equal to the distance between the second score and the second cover plate.

[0016] Further, the depth of the first score is equal to the depth of the second score.

[0017] Further, the trajectory of the score is a straight line, a broken line or a wavy line.

[0018] Further, the cross-sectional shape of the score is a polygon or an arc.

[0019] Further, the shell and the cover plate are connected by laser welding or ultrasonic welding.

[0020] According to another aspect of the present application, a battery assembly is provided, comprising a battery cell and a battery shell, the battery cell is arranged in the battery shell, and the battery shell is the battery shell described above.

[0021] The technical scheme of the present application is applied, the shell is mainly used for accommodating and packaging the battery assembly, the cover plate is used for closing the top of the shell to ensure the sealing of the battery, and the score is a pre-designed weakening structure, the score is arranged along the inner wall of the shell in a circumferential direction to form a closed ring, when the internal pressure of the battery reaches a certain degree, the material at the score will be broken first to form a safe pressure relief channel. The battery shell provided by the present application solves the problem that the existing battery shell sets the explosion-proof score in a local stress concentration area of the shell to cause the explosion-proof valve score area to fail prematurely, ensures that the explosion-proof valve score can be opened in time, and can completely release the internal pressure after being opened, thereby improving the safety of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0022] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the exemplary embodiments of the present application and their description, serve to explain the present application, and do not constitute an improper limitation of the present application. In the drawings:

[0023] Figure 1 A front view of a battery shell of an embodiment of the utility model is shown; and

[0024] Figure 2 A front view of a battery shell of another embodiment of the utility model is shown.

[0025] Among them, the above-mentioned drawing includes the following figure marks:

[0026] 1, shell; 2, cover plate; 21, first cover plate; 22, second cover plate; 3, score; 31, first score; 32, second score. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.The utility model will be described in detail below with reference to the drawings and in combination with embodiments.

[0028] Combined with the drawings shown in Figure 1 And Figure 2 The utility model provides a kind of battery shell, which includes shell 1, cover plate 2 and score 3, cover plate 2 is covered on shell 1, and score 3 extends along the surface of shell 1 circumferentially and forms closed ring.

[0029] In the above technical solution, shell 1 is mainly used to accommodate and package battery components;Cover plate 2 is used to close the top of shell 1, to ensure the sealing of the battery interior;Score 3 is a kind of pre-designed weakening structure, which can be arranged on the inner wall or outer wall of shell 1, or on both the inner wall and the outer wall, and is arranged circumferentially along the side wall of shell 1 to form a closed ring. When the internal pressure of the battery reaches a certain degree, the material at score 3 will break first, forming a safe pressure relief channel. The battery shell provided by the utility model solves the problem that the existing battery shell sets the explosion-proof score in the local part of the shell to form a stress concentration area, which causes the explosion-proof valve score area to fail prematurely, ensures that the explosion-proof valve score can be opened in time, and can completely release the internal pressure after opening, thereby improving the safety of the battery.

[0030] In one embodiment, an electric core is arranged in shell 1, and score 3 is arranged on the inner wall of shell 1 between cover plate 2 and the electric core.

[0031] In the above technical solution, the score 3 is arranged on the inner wall of the shell 1 between the cover plate 2 and the battery cell, so that the breaking area of the score 3 and the pressure relief area formed after the breaking of the score 3 are larger than those of the explosion-proof valve arranged only on the cover plate, which means that the breaking at the score 3 can release the internal pressure faster and more uniformly when the battery is in thermal runaway, thereby reducing the risk of battery explosion and improving the safety of battery pressure relief. Meanwhile, arranging the score 3 on the inner wall can also improve the aesthetics of the appearance of the battery shell.

[0032] In one embodiment, the score 3 is arranged on the outer wall of the shell 1 between the cover plate 2 and the battery cell.

[0033] In the above technical solution, the score 3 is arranged on the outer wall, thereby forming a closed annular weak area on the outer surface of the shell 1. When thermal runaway occurs inside the battery, the shell 1 will preferentially break along the closed annular score 3, thereby quickly and uniformly releasing the internal pressure. In addition, arranging the score 3 on the outer wall facilitates the processing of the score 3, while ensuring the flatness of the inner surface of the shell 1, thereby preserving the structural strength inside the shell 1.

[0034] In one embodiment, the plane in which the edge of the score 3 closest to the cover plate 2 is located is parallel to the cover plate 2.

[0035] In the above technical solution, the plane in which the edge of the score 3 closest to the cover plate 2 is located is parallel to the cover plate 2, which helps to ensure that the pressure distribution of the material around the score 3 is more uniform when the pressure rises, thereby improving the predictability and consistency of the breaking of the score 3 and avoiding unexpected breaking caused by excessive local pressure, thereby ensuring the reliability of the explosion-proof score 3.

[0036] In one embodiment, the first end of the battery shell is provided with a first cover plate 21, and the side of the shell 1 close to the first cover plate 21 is provided with a first score 31.

[0037] In the above technical solution, the first cover plate 21 is usually connected to the positive or negative electrode of the battery, providing electrical connection between the outside of the battery and the internal battery cell. At the same time, the first cover plate 21 is tightly connected to the shell 1 by welding or other means, ensuring the sealing of the internal environment of the battery and protecting the battery from impurities such as water and dust in the external environment. In addition, when the battery is under pressure, the first cover plate 21 helps to maintain the overall structural stability of the battery. The first score 31 is located close to the first cover plate 21, and when it breaks, it can control the direction of pressure relief, avoiding the direct impact of gas on the electrical connection point or external equipment, and reducing possible damage.

[0038] In one embodiment, the second end of the battery shell is provided with a second cover plate 22, and the side of the shell 1 close to the second cover plate 22 is provided with a second score 32.

[0039] In the above technical solution, the second cover plate 22 is usually connected with the positive electrode or the negative electrode of the battery, providing electrical connection between the outside and the internal cell of the battery, and the second cover plate 22 is tightly connected with the shell 1 by welding or the like, ensuring the sealing of the internal environment of the battery and protecting the battery from impurities such as water and dust in the external environment. In addition, when the battery is under pressure, the second cover plate 22 helps to maintain the stability of the overall structure of the battery. The second notch 32 is located near the second cover plate 22, and when it breaks, it can control the direction of pressure relief, avoiding the gas directly impacting the electrical connection point or external equipment, and reducing the possible damage.

[0040] In one embodiment, the distance between the first notch 31 and the first cover plate 21 is 4mm-10mm.

[0041] In the above technical solution, the cover plate is usually fixed to the shell by laser welding or the like. Laser welding can produce local high temperature, and if the notch is too close to the cover plate, the heat generated during the welding process may affect the performance of the material at the notch, causing inconsistent opening pressure and affecting the reliability of the explosion-proof valve. Therefore, maintaining a distance of 4mm-10mm helps to place the first notch 31 outside the heat-affected zone of the laser welding of the first cover plate 21, ensuring the stable performance of the first notch 31 and not being affected by the temperature change during the welding process of the first cover plate 21. In addition, the notch will weaken the structural strength of the material, and if the distance is too close to the cover plate, it may affect the strength of the connection between the cover plate and the shell, causing the stability of the overall structure of the battery to decrease. A distance of 4mm-10mm can ensure that there is enough material thickness between the first notch 31 and the first cover plate 21, thereby maintaining the structural strength of the battery shell and reducing the impact of notch breaking on the overall performance of the shell.

[0042] In one embodiment, the distance between the second notch 32 and the second cover plate 22 is 4mm-10mm.

[0043] In the above technical solution, maintaining a distance of 4mm-10mm helps to place the second notch 32 outside the heat-affected zone of the laser welding of the second cover plate 22, ensuring the stable performance of the second notch 32 and not being affected by the temperature change during the welding process of the second cover plate 22. In addition, the notch will weaken the structural strength of the material, and if the distance is too close to the cover plate, it may affect the strength of the connection between the cover plate and the shell, causing the stability of the overall structure of the battery to decrease. A distance of 4mm-10mm can ensure that there is enough material thickness between the second notch 32 and the second cover plate 22, thereby maintaining the structural strength of the battery shell and reducing the impact of notch breaking on the overall performance of the shell.

[0044] In one embodiment, the depth of the first notch 31 is 0.2mm-0.3mm.

[0045] In the above technical solution, the depth of the notch is directly related to the level of the pressure relief threshold. By setting the depth of the first notch 31 in the range of 0.2mm-0.3mm, it can be ensured that the material at the first notch 31 can effectively and timely break when the internal pressure of the battery abnormally rises to the pressure relief threshold, realizing safe pressure relief. If the notch is too deep, it will excessively weaken the structural strength of the shell, increasing the risk of the battery breaking when subjected to external physical impact. On the contrary, if the notch is too shallow, it may not effectively break when the internal pressure of the battery abnormally rises, affecting the explosion-proof performance. Therefore, by setting the depth of the first notch 31 to 0.2mm-0.3mm, the structural strength of the shell is maximally maintained while ensuring that the first notch 31 can effectively break.

[0046] In one embodiment, the depth of the second notch 32 is 0.2mm-0.3mm.

[0047] In the above technical solution, the depth of the notch is directly related to the level of the pressure relief threshold. By setting the depth of the second notch 32 in the range of 0.2mm-0.3mm, it can be ensured that the material at the second notch 32 can effectively and timely break when the internal pressure of the battery abnormally rises to the pressure relief threshold, realizing safe pressure relief. If the notch is too deep, it will excessively weaken the structural strength of the shell, increasing the risk of the battery breaking when subjected to external physical impact. On the contrary, if the notch is too shallow, it may not effectively break when the internal pressure of the battery abnormally rises, affecting the explosion-proof performance. Therefore, by setting the depth of the second notch 32 to 0.2mm-0.3mm, the structural strength of the shell is maximally maintained while ensuring that the second notch 32 can effectively break.

[0048] In one embodiment, the distance between the first notch 31 and the first cover plate 21 is equal to the distance between the second notch 32 and the second cover plate 22.

[0049] In the above technical solution, by setting the equal distance, it can be ensured that the opening pressures on both sides of the positive and negative electrodes are consistent, so that the battery can be opened at a preset and consistent pressure value when the pressure on either side rises, improving the safety and reliability of the explosion-proof valve. The notch will weaken the structural strength of the battery shell, and the equal distance can ensure that the structural strength and stability of the shell on both sides of the positive and negative electrodes are similar when the battery is subjected to pressure, avoiding asymmetric breaking due to lower unilateral structural strength, and improving the overall structural performance and durability of the battery.

[0050] In one embodiment, the depth of the first notch 31 is equal to the depth of the second notch 32.

[0051] In the above technical solution, the depth of the first score 31 is equal to the depth of the second score 32, which can ensure that the first score 31 and the second score 32 have the same opening pressure under the same conditions, helping to ensure that the two explosion-proof valve scores open at the same time or almost simultaneously, providing more uniform pressure relief efficiency, thereby improving the safety and reliability of the explosion-proof valve. In addition, if the depths of the two scores are inconsistent, the resistance of the pressure relief path and the pressure relief rate will also be different, which may cause one score to open before the other, uneven pressure relief, affecting the internal thermal balance of the battery, thereby increasing the risk of thermal runaway.

[0052] In one embodiment, the trajectory of the score 3 is a straight line, a broken line, or a wavy line.

[0053] In the above technical solution, the design of the straight line score 3 is beneficial to control the depth and width of the score 3, simplify the manufacturing process, and reduce production costs. However, the breaking direction of the straight line score 3 may be relatively fixed, which may limit the range of gas release. The broken line score 3 can increase the complexity and length of the score 3 by introducing turning points in the score path, thereby providing a larger pressure relief area. The broken line design can also increase the flexibility of the pressure relief path, allowing gas to be released in multiple directions, which helps to reduce the local pressure of the battery and reduce the risk of thermal runaway. The wavy line score combines the advantages of straight line and broken line, with a more complex path and longer length, it can provide a larger pressure relief area and more flexible gas release direction. The design of the wavy line score helps to further disperse the stress when the score breaks, reduce the local pressure peak, and improve the pressure relief efficiency and safety.

[0054] In one embodiment, the cross-sectional shape of the score 3 is a polygon or an arc.

[0055] In the above technical solution, the polygonal cross-section can provide multiple material stress concentration points, which become multiple breaking points when the pressure reaches a certain level, making the pressure relief more uniform and controllable. The arc-shaped cross-section can provide a smooth transition, reducing material stress concentration, allowing the score to expand along a smooth curve when it breaks, avoiding the formation of sharp edges or fragments, reducing the risk of damage to internal and external components of the battery, while still maintaining good pressure relief capability. In terms of manufacturing process, both shapes can be achieved by modern laser cutting or mechanical processing technology, but the polygonal score may require more precise positioning and cutting, while the arc-shaped score requires a smooth cutting path. Selecting a shape that matches the needs of the manufacturing equipment and application scenario can optimize production efficiency and reduce production costs.

[0056] In one embodiment, the shell 1 and the cover plate 2 are connected by laser welding or ultrasonic welding.

[0057] In the above technical solution, laser welding and ultrasonic welding can form a strong connection between the shell 1 and the cover plate 2, improving the structural strength and sealing effect of the battery case, thereby improving the ability to resist external force impact, maintain the overall structure, and prevent external substances such as moisture and dust from entering the battery during transportation and use. Laser welding can precisely control the size of the heat-affected zone, and ultrasonic welding can control the depth and strength of the weld, which helps to improve the welding quality and consistency and reduce defects during production. Laser welding and ultrasonic welding can control the heat diffusion that occurs during the welding process, avoiding the adverse effects of the heat generated by welding on sensitive components inside the battery, especially the area of the explosion-proof valve notch, ensuring that the explosion-proof valve notch achieves the desired explosion-proof effect.

[0058] In one embodiment, the depth of the first notch 31 and the depth of the second notch 32 are both less than the thickness of the shell 1, avoiding separation of the shell 1 and the cover plate 2 at the notch.

[0059] As shown in Figure 1 and Figure 2 The utility model also provides a battery assembly, including electric core and battery case, electric core sets up in battery case, battery case is above -mentioned battery case.

[0060] In the above technical solution, by using the battery case with the closed ring-shaped explosion-proof notch as the shell of the battery assembly, the problem of premature failure of the explosion-proof valve notch in existing battery assemblies can be avoided, thereby improving the safety of the battery assembly.

[0061] From the above description, it can be seen that the above-mentioned embodiments of the utility model realize the following technical effects: the shell 1 is mainly used for accommodating and packaging the battery assembly; the cover plate 2 is used for closing the top of the shell 1, ensuring the sealing of the battery interior; the notch 3 is a pre-designed weakening structure, and the notch 3 is arranged along the inner wall of the shell 1 in a closed ring shape, when the internal pressure of the battery reaches a certain degree, the material at the notch 3 will break first, forming a safe pressure relief channel. The battery case provided by the utility model solves the problem of premature failure of the explosion-proof notch area caused by setting the explosion-proof notch in the local stress concentration area of the shell in the existing battery case, ensures that the explosion-proof valve notch can be opened in time, and can completely release the internal pressure after opening, thereby improving the safety of the battery.

[0062] Obviously, the above-described embodiments are only a part of the embodiments of the utility model, not all. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the utility model.

[0063] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0064] The preferred embodiments of the present application have been described above with the aid of drawing provided only by way of example and therefore changes in form and detail can be made therein without departing from the spirit and scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A battery housing, characterized by The battery shell comprises a shell (1), a cover plate (2) and a score line (3), the cover plate (2) is arranged on the shell (1), and the score line (3) extends along the surface of the shell (1) in a circumferential direction and forms a closed ring.

2. The battery case of claim 1, wherein, An electric core is arranged in the shell (1), and the score line (3) is arranged on the inner wall of the shell (1) between the cover plate (2) and the electric core; and / or the score line (3) is arranged on the outer wall of the shell (1) between the cover plate (2) and the electric core.

3. The battery case of claim 1, wherein, The plane where the most side edge of the score line (3) is located is parallel to the cover plate (2).

4. The battery case of claim 2, wherein, The first end of the battery shell is provided with a first cover plate (21), the shell (1) is provided with a first score line (31) close to the first cover plate (21), and / or the second end of the battery shell is provided with a second cover plate (22), and the shell (1) is provided with a second score line (32) close to the second cover plate (22).

5. The battery case of claim 4, wherein, The distance between the first score line (31) and the first cover plate (21) is 4mm-10mm; and / or the distance between the second score line (32) and the second cover plate (22) is 4mm-10mm.

6. The battery case of claim 4, wherein, The depth of the first score line (31) is 0.2mm-0.3mm; and / or the depth of the second score line (32) is 0.2mm-0.3mm.

7. The battery case of claim 5, wherein, The distance between the first score line (31) and the first cover plate (21) is equal to the distance between the second score line (32) and the second cover plate (22).

8. The battery case of claim 6, wherein, The depth of the first score line (31) is equal to the depth of the second score line (32).

9. The battery case of claim 1, wherein, The track of the score line (3) is a straight line, a broken line or a wavy line; and / or the cross-sectional shape of the score line (3) is a polygon or an arc.

10. The battery case of claim 1, wherein, The shell (1) and the cover plate (2) are connected by laser welding or ultrasonic welding.

11. A battery assembly characterized by, The battery shell comprises an electric core and a battery shell, the electric core is arranged in the battery shell, and the battery shell is the battery shell according to any one of claims 1-10. The battery shell comprises an electric core and a battery shell, the electric core is arranged in the battery shell, and the battery shell is the battery shell according to any one of claims 1-10.

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