Explosion-proof valve structure, top cover structure, and power battery

Abstract

An explosion-proof valve structure, a top cover structure, and a power battery. The explosion-proof valve structure comprises a body (1), a score (2) and a buffer rib (3), wherein the score (2) is annularly arranged on the body (1), and the buffer rib (3) is arranged on the body (1) and located between the score (2) and the edge of the body (1), the cross-section of the buffer rib (3) being bent.

Description

Explosion-proof valve structure, top cover structure and power battery

[0001] This application claims priority to the Chinese patent application No. 202420728595.1 filed on April 10, 2024 with the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of power batteries, for example, to an explosion-proof valve structure, a top cover structure and a power battery. BACKGROUND

[0003] As a key component of a power battery, a battery top cover has a significant impact on the energy density, economy and safety of the power battery. To ensure the safe use of the power battery, an explosion-proof valve structure is usually installed on the battery top cover. When the battery is improperly charged, disconnected or exposed to harsh weather, a large amount of gas is generated inside the battery and accompanied by a sharp rise in temperature. The internal pressure is too high to burst the explosion-proof valve structure to achieve pressure relief.

[0004] Square aluminum structural battery is widely used due to its advantages of light weight and low price. However, the strength of aluminum material is low. To meet the strength requirement of the explosion-proof valve structure, a very thick material is needed to make it, which will occupy a large amount of internal space of the battery, resulting in a low energy density of the power battery. Therefore, high-strength stainless steel material is gradually used as the material for making the explosion-proof valve structure. Under the condition of meeting the strength requirement, the thickness of stainless steel is reduced by 50%-70% compared with aluminum, which can save a large amount of internal space of the battery. The explosion-proof valve made of extremely thin stainless steel material is prone to crack during the welding process with the top cover due to thermal expansion and contraction, which may cause the power battery to leak.

[0005] SUMMARY

[0006] The present application provides an explosion-proof valve structure that can meet the pressure relief requirement and prevent the notch from cracking.

[0007] The explosion-proof valve structure comprises a body, a notch and a buffer rib. The notch is annularly arranged on the body. The buffer rib is arranged on the body and located between the notch and the edge of the body. The cross section of the buffer rib is in a bent shape.

[0008] In an embodiment, the buffer rib is concave, and the buffer rib and the body cooperate to form a groove. Alternatively, the buffer rib is convex, and the buffer rib and the body cooperate to form a protrusion.

[0009] In an embodiment, the notch comprises an opening section and a residual section. The two ends of the opening section are respectively connected to the two ends of the residual section. The thickness of the residual section is greater than the thickness of the opening section.

[0010] In one embodiment, the two ends of the buffer rib are flush with the two ends of the length direction of the opening section.

[0011] In one embodiment, the thickness of the buffer rib is greater than the thickness of the notch.

[0012] In one embodiment, the cross-sectional shape of the buffer rib is arc-shaped, U-shaped or V-shaped.

[0013] In one embodiment, the body includes a concave portion and an edge portion, the concave portion is located in the middle region of the body, the edge portion surrounds the concave portion, and the thickness of the concave portion is less than the thickness of the edge portion, the notch is arranged in the concave portion, and the buffer rib is arranged in the edge portion.

[0014] In one embodiment, the body is made of stainless steel plate.

[0015] The application provides a top cover structure which can prevent air leakage.

[0016] The top cover structure includes a top cover sheet and the above-mentioned explosion-proof valve structure, the top cover sheet has a mounting hole, and the body is circumferentially welded to the hole wall of the mounting hole.

[0017] The application provides a power battery with high safety factor.

[0018] The power battery includes a shell, a battery cell and the above-mentioned top cover structure, one end of the shell is open, the top cover sheet is circumferentially connected to the open end of the shell, the top cover sheet and the shell cooperate to form a mounting cavity, and the battery cell is arranged in the mounting cavity. BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a structural schematic view of an explosion-proof valve structure provided by an embodiment of the application;

[0020] FIG. 2 is a sectional view of a top cover structure provided by an embodiment of the application;

[0021] FIG. 3 is an enlarged view of A in FIG. 2;

[0022] FIG. 4 is a structural schematic view of a top cover sheet provided by an embodiment of the application;

[0023] FIG. 5 is a structural schematic view of a top cover structure provided by an embodiment of the application.

[0024] In the drawings:

[0025] 1, body; 11, concave portion; 12, edge portion; 2, notch; 21, opening section; 22, residual section; 3, buffer rib;

[0026] 10, top cover sheet; 101, mounting hole; 102, positive electrode hole; 103, negative electrode hole; 104, liquid injection hole. DETAILED DESCRIPTION

[0027] In the description of the present application, unless specifically defined and limited otherwise, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the meaning of the above terms in the present application can be understood according to the situation.

[0028] In the present application, unless specifically defined and limited otherwise, the first feature "on" or "under" the second feature can include that the first feature and the second feature are in direct contact, or that the first feature and the second feature are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0029] In the description of the present embodiment, the terms "up", "down", "right", and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0030] Embodiment one

[0031] Due to the high strength characteristics of stainless steel material, under the premise of meeting the strength requirements of explosion-proof valve, the thickness of stainless steel material is reduced by 50%-70% compared with aluminum material, which greatly saves the internal space of power battery, and the explosion-proof valve made of very thin stainless steel material is used. In order to meet the requirement of explosion of power battery under certain air pressure, the notch residual thickness is very thin, so in the welding process with the top cover sheet, the notch is easy to crack due to thermal expansion and cold contraction, and then causes the power battery to leak.

[0032] The present embodiment provides an explosion-proof valve structure, which can prevent the notch thereon from cracking under the premise of meeting the pressure relief requirement of the explosion-proof valve structure made of stainless steel material.

[0033] The explosion-proof valve structure is made of stainless steel plate, and comprises a body 1, a notch 2 and a buffer rib 3. The notch 2 is arranged around the body 1, and the buffer rib 3 is arranged on the body 1 and located between the notch 2 and the edge of the body 1. The buffer rib 3 is integrally formed with the body 1. When a large amount of gas is generated inside the power battery and the temperature rises sharply, the internal pressure is too high, and the gas will rush out along the notch 2 to open the explosion-proof valve structure to achieve the purpose of pressure relief. By arranging the buffer rib 3, during the welding process of the body 1 and the top cover sheet 10, thermal expansion and contraction will first cause the buffer rib 3 to be pulled, thereby buffering the pulling of the notch 2 caused by thermal expansion and contraction, effectively preventing the notch 2 from cracking, and avoiding gas leakage.

[0034] In this embodiment, the body 1 comprises a recess 11 and an edge portion 12. The recess 11 is located in the middle region of the body 1, and the edge portion 12 surrounds the recess 11. The thickness of the recess 11 is less than the thickness of the edge portion 12. The notch 2 is arranged in the recess 11, and the buffer rib 3 is arranged in the edge portion 12. When the internal pressure is too high, the gas will rush out along the notch 2 to open the recess 11, while the edge portion 12 is still connected to the top cover sheet 10, ensuring the overall stability of the explosion-proof valve structure and preventing the entire explosion-proof valve structure from being opened when the internal pressure is too high.

[0035] The notch 2 comprises an opening section 21 and a residual section 22. The two ends of the opening section 21 are respectively connected to the two ends of the residual section 22. In this embodiment, the thickness of the residual section 22 is greater than the thickness of the opening section 21. When the internal pressure is too high, the opening section 21 will first crack and continue to extend. When the crack extends along the opening section 21 to the residual section 22, the crack will be effectively blocked due to the greater thickness of the residual section 22 than that of the opening section 21, thereby avoiding the overall falling of the recess 11 and causing harm, and achieving the semi-opening of the explosion-proof valve structure and improving the safety performance.

[0036] For example, referring to FIG. 1, in this embodiment, the notch 2 is formed by stamping and has a runway shape. The opening section 21 comprises a first straight edge and two circular arcs. One end of each of the two circular arcs is connected to the two end portions of the first straight edge. The residual section 22 comprises a second straight edge. The other end of each of the two circular arcs is connected to the two end portions of the second straight edge. When the crack extends along the two circular arcs to the end portions of the second straight edge, it is blocked. The second straight edge is always connected to the body 1. In other feasible embodiments, the notch 2 can also have a square shape, a circular shape, a W shape or a Z shape, which is not limited in this embodiment.

[0037] The cross section of the buffer rib 3 is in a bent shape. For example, referring to Fig. 3, the buffer rib 3 is concave, and the buffer rib 3 and the body 1 form a groove. During the welding process of the body 1 and the top cover sheet 10, thermal expansion and contraction first causes the buffer rib 3 to be pulled, and the buffer rib 3 is in a state of being lifted or continuously concave. The buffer rib 3 can buffer the pull of the thermal expansion and contraction on the notch 2. In some embodiments, the buffer rib 3 is convex, and the buffer rib 3 and the body 1 form a convex. During the welding process of the body 1 and the top cover sheet 10, thermal expansion and contraction first causes the buffer rib 3 to be pulled, and the buffer rib 3 is in a state of being pulled down or continuously convex. The buffer rib 3 can also buffer the pull of the thermal expansion and contraction on the notch 2.

[0038] For example, the cross section of the buffer rib 3 is in an arc shape, a U shape or a V shape, and is in a bent shape to buffer the pull of the thermal expansion and contraction.

[0039] The thickness of the buffer rib 3 is greater than the thickness of the notch 2, so that the buffer rib 3 is first broken when the internal pressure is too large. In this embodiment, the thickness of the buffer rib 3 is the same as the thickness of other areas of the edge portion 12.

[0040] In this embodiment, the opening section 21 is the thinnest area of the body 1, the buffer rib 3 is arranged around the opening section 21, and the buffer rib 3 is located between the opening section 21 and the edge of the body 1. The two ends of the buffer rib 3 are flush with the two ends of the opening section 21 in the length direction, that is, the buffer rib 3 extends from one end of the opening section 21 to the other end of the opening section 21, so as to buffer the pull of the thinnest opening section 21 of the body 1, and at the same time, the structural strength is enhanced, and the opening section 21 can be effectively prevented from cracking.

[0041] The explosion-proof valve structure provided in this embodiment is arranged between the opening section 21 of the notch 2 and the edge of the body 1. On the one hand, the structural strength is enhanced, and on the other hand, during the welding process of the body 1 and the top cover sheet 10, thermal expansion and contraction first causes the buffer rib 3 to be pulled, and the buffer rib 3 buffers the pull of the thermal expansion and contraction on the notch 2. Therefore, the notch 2 on the explosion-proof valve structure made of stainless steel can be prevented from cracking, and the power battery can be prevented from leaking during use.

[0042] Embodiment Two

[0043] This embodiment provides a top cover structure. Referring to Figs. 4 and 5, the top cover structure includes a top cover sheet 10 and the above-mentioned explosion-proof valve structure. The top cover sheet 10 has a mounting hole 101, and the edge of the body 1 in the explosion-proof valve structure is circumferentially welded to the hole wall of the mounting hole 101. The welding method is laser welding, which has the characteristics of fast welding speed and large depth-width ratio.

[0044] The top cover sheet 10 also has a positive electrode hole 102, a negative electrode hole 103 and a liquid injection hole 104. The positive electrode pole can pass through the positive electrode hole 102 and lead out the internal battery cell. The negative electrode pole can pass through the negative electrode hole 103 and lead out the internal battery cell. The liquid injection hole 104 is arranged to supplement the electrolyte in the power battery, so as to ensure the power supply capacity of the power battery.

[0045] The top cover structure provided by the embodiment can effectively avoid the power battery from leaking gas during use.

[0046] Embodiment Three

[0047] The embodiment provides a power battery, which comprises a shell, a battery cell and the top cover structure as described above. One end of the shell is open. The top cover sheet 10 is circumferentially connected to the open end of the shell. The top cover sheet 10 cooperates with the shell to form a mounting cavity. The battery cell is arranged in the mounting cavity.

[0048] The top cover structure provided by the embodiment can effectively avoid gas leakage and has high safety.

Claims

1. An explosion-proof valve structure, comprising a body (1), a notch (2) and a buffer rib (3), wherein the notch (2) is arranged on the body (1) in a ring, and the buffer rib (3) is arranged on the body (1) and is located between the notch (2) and the edge of the body (1), and the cross section of the buffer rib (3) is bent.

2. The explosion-proof valve structure according to claim 1, wherein: The buffer rib (3) is concave, and the buffer rib (3) cooperates with the body (1) to form a groove; or the buffer rib (3) is convex, and the buffer rib (3) cooperates with the body (1) to form a protrusion.

3. The explosion-proof valve structure according to claim 1, wherein: The notch (2) comprises an opening section (21) and a residual section (22), the two ends of the opening section (21) are respectively connected to the two ends of the residual section (22), and the thickness of the residual section (22) is greater than the thickness of the opening section (21).

4. The explosion-proof valve structure according to claim 3, wherein: The two ends of the buffer rib (3) are respectively flush with the two ends of the opening section (21) in the length direction.

5. The explosion-proof valve structure according to claim 1, wherein: The thickness of the buffer rib (3) is greater than the thickness of the notch (2).

6. The explosion-proof valve structure according to claim 1, wherein: The cross-sectional shape of the buffer rib (3) is arc-shaped, U-shaped or V-shaped.

7. The explosion-proof valve structure according to claim 1, wherein: The body (1) comprises a recess (11) and an edge portion (12), wherein the recess (11) is located in a middle area of ​​the body (1), the edge portion (12) surrounds the recess (11), and the thickness of the recess (11) is smaller than the thickness of the edge portion (12), the notch (2) is arranged in the recess (11), and the buffer rib (3) is arranged in the edge portion (12).

8. The explosion-proof valve structure according to claim 1, wherein: The body (1) is made of stainless steel plate.

9. A top cover structure, comprising a top cover plate (10) and the explosion-proof valve structure according to any one of claims 1 to 8, wherein the top cover plate (10) has a mounting hole (101), and the body (1) is circumferentially welded to the hole wall of the mounting hole (101).

10. A power battery, comprising a shell, a battery cell and the top cover structure according to claim 9, wherein one end of the shell is open, the top cover sheet (10) is circumferentially connected to the open end of the shell, the top cover sheet (10) cooperates with the shell to form an installation cavity, and the battery cell is arranged in the installation cavity.

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