Explosion-proof valves, battery cell assemblies and batteries

Abstract

This application relates to the field of battery component technology and discloses an explosion-proof valve, a battery cell assembly, and a battery, the explosion-proof valve comprising a valve body having an inner and outer side, a buffer groove installed in the valve body and recessed toward the inside of the valve body to form an annular groove structure, and a notched groove provided around the bottom wall of the buffer groove along the direction of extension of the buffer groove. The buffer groove formed in the valve body absorbs vibration energy and can effectively reduce the stress on the notched groove under the conditions of battery cell production, pack assembly, and overall vehicle vibration, making it less likely for the notched groove to fail due to fatigue fracture and ensuring the reliability of the explosion-proof valve. Furthermore, since the notched groove of the explosion-proof valve is located on the wall surface of the buffer groove on the valve body, the design maximization of the valve opening area of ​​the explosion-proof valve is ensured, the pressure release speed is improved, and pressure can be quickly released when the battery cell experiences thermal runaway, reducing the risk of the battery cell exploding.

Description

Technical Field

[0001] This application relates to the field of battery member technology, and more particularly to explosion-proof valves, battery cell assemblies, and batteries.

Background Art

[0002] An explosion-proof valve for a battery cell is a safety protection device applied to lithium batteries and other types of battery cells. The explosion-proof valve for a battery cell can release the internal pressure by providing a notch. When the internal pressure of the battery is too high, the notch of the explosion-proof valve makes it easier for the valve to be pushed out. As a result, the internal gas is released, the internal pressure is reduced, and an explosion caused by too rapid pressurization of the battery body can be prevented.

[0003] With the increase in the rapid charging speed of battery cells for power batteries, the voltage of the entire battery pack continues to rise. Therefore, it is necessary to install more cells for each battery pack. As a result, the thickness of each individual cell becomes thinner. When the battery cell becomes thinner, the area where the explosion-proof valve can be installed decreases. Under the condition of not changing the opening pressure, the remaining thickness of the notch becomes very thin, and the resistance to stress decreases. Therefore, under the conditions of battery cell production, pack assembly, and vehicle vibration, the notch of the explosion-proof valve is stressed and prone to fatigue fracture and failure, which exacerbates the problem.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of this, this application provides an explosion-proof valve, a battery cell assembly, and a battery to solve the problem that the remaining thickness of the notch of the explosion-proof valve is thin and fatigue fracture is likely to occur in the notch under stress.

Means for Solving the Problems

[0005] In a first aspect, this application provides an explosion-proof valve, and the explosion-proof valve includes a valve body having an inner side and an outer side, a buffer groove installed on the valve body and recessed toward the inner side of the valve body to form an annular concave groove structure The device comprises a notched groove formed around the bottom wall of the buffer groove along the extending direction of the buffer groove.

[0006] The beneficial effects are as follows: The buffer grooves formed in the valve body absorb vibration energy, effectively reducing the stress on the grooves under the conditions of battery cell production, pack assembly, and overall vehicle vibration. This makes it less likely for the grooves to fail due to fatigue fracture, ensuring the reliability of the explosion-proof valve. Furthermore, because the grooves of the explosion-proof valve are located on the bottom wall of the buffer grooves on the valve body, the opening area of ​​the explosion-proof valve is maximized, the pressure release speed is improved, and pressure can be released quickly when the battery cells experience thermal runaway, reducing the risk of battery cell explosion. In addition, because the grooves are located on the bottom wall of the buffer grooves, the residual thickness of the grooves is necessarily thinner than the bottom wall of the buffer grooves. This ensures the buffering effect of the buffer grooves while also ensuring that the grooves will rupture instead of the buffer grooves when the internal pressure of the battery cells rises.

[0007] In one selective embodiment, the grooves form a continuous closed loop, and the grooves include a deep groove portion and a shallow groove portion, wherein the residual thickness of the deep groove portion is less than the residual thickness of the shallow groove portion.

[0008] The beneficial effects are as follows: The grooves include deep and shallow sections, with the deep sections functioning as explosive sections and the shallow sections acting as connecting sections, so that even if there is a rupture in the deep section of the explosion-proof valve, the shallow section will still function. groove The part can still connect the central and outer parts of the valve body, preventing the central part of the valve body from popping out under internal pressure and posing a danger. Furthermore, at the same valve opening pressure, the groove depth of the grooves forming a continuous closed loop is the same as the grooves that do not form a closed loop in related technologies. groove Since the groove depth can be set to be shallower than the main groove depth, and even shallower for grooves including the deep groove section, the requirements for machining precision are further reduced, and as a result, production costs are effectively reduced.

[0009] In one selective embodiment, the transition between the deep groove portion and the shallow groove portion is either by a step or by a smooth transition.

[0010] The beneficial effects are as follows: When a step-like transition is applied between the deep groove and the shallow groove, the manufacturing process is simpler, saving time and labor. However, when a smooth transition is applied between the deep groove and the shallow groove, the stress of the transition is effectively reduced, improving the stability of the explosion-proof valve.

[0011] In one selective embodiment, the cross-sectional shape of the buffer groove is U-shaped.

[0012] The beneficial effects are as follows: The side walls of the U-shaped groove function as a structure that buffers and absorbs vibrations and deformations, resulting in reduced vibrations transmitted to the bottom wall, reduced stress generation in the grooves, improved buffering performance, and keeping the grooves intact during installation. In addition, the U-shaped buffer groove has a simple structure, making it easy to produce and manufacture.

[0013] In one selective embodiment, the cross-sectional shape of the groove is an inverted trapezoid.

[0014] The beneficial effects are as follows: The inverted trapezoidal cross-section of the grooves makes it easier for the central fracture portion of the valve body to detach during pressure release, increasing the explosive effect and improving the pressure release effect.

[0015] In one selective embodiment, at least the cross-sectional shape of the deep groove portion is an inverted trapezoid.

[0016] The beneficial effects are as follows: By setting the cross-sectional shape of at least the deep groove section as an inverted trapezoid, the explosive effect is enhanced, and if both the deep groove section and the shallow groove section are set as inverted trapezoids, production can be carried out using the same mold, thus reducing production costs.

[0017] In one selective embodiment, the length of the shallow groove portion accounts for 1 / 10 to 1 / 3 of the total length of the groove.

[0018] The beneficial effects are as follows: The deep groove section releases pressure as an explosive section, so in order to ensure the pressure release effect, the length of the shallow groove section should not be too long; otherwise, it will affect the opening of the explosion-proof valve or lead to an increase in the valve opening pressure. When the length of the shallow groove section accounts for 1 / 10 to 1 / 3 of the total length of the groove, neither affecting the opening of the explosion-proof valve nor leading to an increase in the valve opening pressure occurs. Moreover, even if there is a rupture in the deep groove section, the connection between the central and peripheral parts of the valve body is still ensured by the shallow groove section, preventing the central part from flying out and causing injury.

[0019] In one selective embodiment, the grooves are arranged continuously and are not in a closed loop.

[0020] The beneficial effects are as follows: The grooves are installed continuously and are not closed loops, and have physical connections. In the event of a rupture in the explosion-proof valve, the connection between the central and outer parts of the valve is achieved by the connection, improving safety after pressure release.

[0021] In a second aspect, the present application provides a battery cell assembly, the battery cell assembly is, A positive electrode aluminum sheet with a through groove, The system comprises an explosion-proof valve, as described in any one of the above items, which is sealed and installed within the aforementioned through groove.

[0022] The beneficial effects are as follows: Since the battery cell assembly includes the explosion-proof valve according to this application, it has the same technical effects as the aforementioned explosion-proof valve, and will not be explained again here.

[0023] In a third aspect, the present invention provides a battery comprising the above-described battery cell assembly.

[0024] The beneficial effects are as follows. Since the battery includes the battery cell assembly according to the present application, it has the same technical effects as the battery cell assembly, and will not be repeatedly described herein.

Brief Description of the Drawings

[0025] To more clearly illustrate the specific implementation forms of the present application or the technical solutions in the prior art, the accompanying drawings required for the description of the specific implementation forms of the present application or the prior art will be briefly described below. Of course, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative labor. [Figure 1] It is a schematic perspective structure diagram of the explosion-proof valve according to an embodiment of the present application. [Figure 2] It is a front view of the explosion-proof valve according to an embodiment of the present application. [Figure 3] It is a plan view of the explosion-proof valve according to an embodiment of the present application. [Figure 4] It is a cross-sectional view taken along A-A of FIG. 3. [Figure 5] It is a cross-sectional view taken along B-B of FIG. 3. [Figure 6] It is a schematic enlarged local structure diagram of the J part of FIG. 5. [Figure 7] It is a schematic enlarged local structure diagram of the I part of FIG. 5. [Figure 8] It is a schematic structure diagram of the connection part between the deep groove part and the shallow groove part of the explosion-proof valve according to an embodiment of the present application, showing a stepped transition state. [Figure 9] It is a schematic structure diagram of the connection part between the deep groove part and the shallow groove part of the explosion-proof valve according to an embodiment of the present application, showing a smooth transition state. [Figure 10] It is a schematic exploded structure diagram of the upper cover of the battery cell assembly according to an embodiment of the present application. [Figure 11] It is a front view of the upper cover of the battery cell assembly according to an embodiment of the present application. [Figure 12] It is a left side view of the upper cover of the battery cell assembly according to an embodiment of the present application. [Figure 13]This is a bottom view of the upper cover of a battery cell assembly according to an embodiment of the present application. [Figure 14] This is a plan view of the upper cover of a battery cell assembly according to an embodiment of the present invention. [Figure 15] This is a cross-sectional view of DD in Figure 14. [Figure 16] This is a cross-sectional view at CC in Figure 14. [Modes for carrying out the invention]

[0026] To clarify the purpose, technical solutions, and advantages of the embodiments of this application, the technical solutions will be described clearly and completely below with reference to the drawings relating to the embodiments of this application. Naturally, the embodiments described are only a part of the embodiments of this application, not all of them. A person skilled in the art will find that all other embodiments obtained without creative work based on the embodiments of this application fall within the scope of protection of this application.

[0027] In the description of this application, unless otherwise specified, "multiple" means two or more, and the directions or positional relationships indicated by terms such as "up," "down," "left," "right," "inside," "outside," "front end," "rear end," "first," and "last" are directions or positional relationships based on the drawings, intended to facilitate and simplify the description of this application, and do not indicate or imply that the shown device or element has a specific direction or must be constructed and operated in a specific direction, and therefore should not be understood as limiting this application. Furthermore, terms such as "first," "second," and "third" are used solely for explanatory purposes and should not be interpreted as indicating or implying relative importance.

[0028] In the description of this application, the terms "attachment," "connection," and "connection" should be understood in a broad sense unless specifically defined and limited thereto. For example, they may refer to fixed connections, removable connections, integrated connections, mechanical connections, electrical connections, direct connections, or indirect connections via an intermediate medium. Those skilled in the art will be able to understand the specific meaning of these terms in this application according to the actual circumstances.

[0029] According to a specific embodiment of the present application, an explosion-proof valve 7 is provided, as shown in Figures 1 to 9. The valve body 71 has an inner and an outer side, with the inner side corresponding to the inside of the battery cell, A buffer groove 72 is installed on the valve body 71 and is recessed toward the inside of the valve body 71, forming an annular groove structure, The device includes notched grooves 73 that are provided around the bottom wall of the buffer groove 72 along the direction of extension of the buffer groove 72.

[0030] The beneficial effects are as follows: The buffer groove 72 formed in the valve body 71 absorbs vibration energy, effectively reducing the stress on the groove 73 under the conditions of battery cell production, pack assembly, and overall vehicle vibration, making it less likely for the groove 73 to fail due to fatigue fracture, and ensuring the reliability of the explosion-proof valve 7. Furthermore, because the groove 73 of the explosion-proof valve 7 is located on the bottom wall of the buffer groove 72 on the valve body 71, the opening area of ​​the explosion-proof valve 7 is maximized, the pressure release speed is improved, and pressure can be released quickly when the battery cell experiences thermal runaway, reducing the risk of the battery cell exploding. In addition, because the groove 73 is located on the bottom wall of the buffer groove 72, the residual thickness of the groove 73 is necessarily thinner than the bottom wall of the buffer groove 72, ensuring the buffering effect of the buffer groove 72, while at the same time ensuring that the groove 73 will rupture instead of the buffer groove 72 when the internal pressure of the battery cell rises.

[0031] The residual thickness refers to the thickness remaining after subtracting the groove depth of the groove 73 from the wall thickness of the groove 73 (in this application, the wall thickness of the bottom wall of the buffer groove 72). The residual thickness of the groove 73 is smaller than the wall thickness of the bottom wall of the buffer groove 72.

[0032] Specifically, the wall surface of the valve body 71 is recessed downward to form a buffer groove 72, resulting in a simple structure and a simple molding process. The buffer groove 72 has high structural rigidity and good impact resistance, and can effectively buffer vibrations from being transmitted to the groove 73.

[0033] In one embodiment, the buffer groove 72 is located on the edge closest to the valve body 71.

[0034] By positioning the buffer groove 72 on the edge closest to the valve body 71, the buffer length of the buffer groove 72 is ensured, the pressure release area of ​​the explosion-proof valve 7 can be increased, and as a result, the speed of pressure release is ensured.

[0035] In one selective embodiment, the groove 73 forms a continuous closed loop and includes a deep groove portion 731 and a shallow groove portion 732, wherein the residual thickness of the deep groove portion 731 is less than the residual thickness of the shallow groove portion 732.

[0036] The beneficial effects are as follows: The groove 73 includes a deep groove portion 731 and a shallow groove portion 732, the deep groove portion 731 can function as an explosive portion and the shallow groove portion 732 can serve as a connecting portion, and the explosion-proof valve 7 can function even if there is a fracture in the deep groove portion 731. groove portion 732 However, since the central and outer parts of the valve body can still be connected, the central part of the valve body does not pop out under the action of internal pressure and pose a danger. Furthermore, at the same valve opening pressure, the groove depth of the grooves 73 that form a continuous closed loop is the same as the grooves that do not form a closed loop in related technologies. groove Since the groove depth can be set to be shallower than the main groove depth, and even shallower for grooves including the deep groove section 731, the requirements for machining accuracy are further reduced, and as a result, production costs are effectively reduced.

[0037] As shown in Figures 6 and 7, in this embodiment, the residual thickness T1 of the deep groove portion 731 and the residual thickness T2 of the shallow groove portion 732 of the groove 73 are both smaller than the wall thickness T0 of the bottom wall of the buffer groove 72, i.e., T1 <T2<T0である。

[0038] In some selective embodiments, as shown in Figure 8, the transition between the deep groove portion 731 and the shallow groove portion 732 is by a step.

[0039] When a configuration is applied in which the deep groove portion 731 and the shallow groove portion 732 are transitioned by a step, the manufacturing process is simplified, saving time and labor.

[0040] In some other embodiments, as shown in Figure 9, when a configuration is applied in which the transition between the deep groove portion 731 and the shallow groove portion 732 is smoothed by a transition portion 733, and the transition between the deep groove portion 731 and the shallow groove portion 732 is smoothed, the stress of the transition can be effectively reduced and the stability of the explosion-proof valve 7 can be improved.

[0041] In some selective embodiments, the cross-sectional shape of the buffer groove 72 is U-shaped.

[0042] The side walls of the U-shaped groove function as a structure that buffers and absorbs vibrations and deformations, resulting in reduced vibrations transmitted to the bottom wall, reduced stress generation in the groove 73, avoiding situations where stress concentrates in the groove 73 and causes failure, improving buffering performance, keeping the groove 73 intact during installation, and the U-shaped buffer groove 72 has a simple structure, making production and manufacturing easier.

[0043] In some selective embodiments, the cross-sectional shape of the groove 73 is an inverted trapezoid.

[0044] The inverted trapezoidal shape of the groove 73 makes it easier for the central fracture portion of the valve body 71 to detach when pressure is released, increasing the explosive effect and improving the pressure release effect.

[0045] In some selective embodiments, the cross-sectional shape of at least the deep groove portion 731 is an inverted trapezoid.

[0046] The explosive effect is enhanced by setting the cross-sectional shape of at least the deep groove section 731 as an inverted trapezoid. If both the deep groove section 731 and the shallow groove section 732 are set as inverted trapezoids, they can be produced using the same mold, thus reducing production costs.

[0047] In some selective embodiments, the length of the shallow groove portion 732 accounts for 1 / 10 to 1 / 3 of the total length of the groove 73.

[0048] Since the deep groove portion 731 releases pressure as an explosive portion, the length of the shallow groove portion 732 should not be too long in order to ensure the effect of pressure release; otherwise, it will affect the opening of the explosion-proof valve 7 or lead to an increase in the opening pressure of the explosion-proof valve 7. When the length of the shallow groove portion 732 occupies 1 / 10 to 1 / 3 of the total length of the groove 73, neither affecting the opening of the explosion-proof valve 7 nor leading to an increase in the opening pressure of the explosion-proof valve 7 occurs. Moreover, even if the deep groove portion 731 ruptures, the connection between the central and peripheral parts of the valve body is still ensured by the shallow groove portion 732, preventing the central part from flying out and causing injury.

[0049] In some selective embodiments, the grooves 73 are arranged continuously and are not in a closed loop.

[0050] The grooves 73 are installed continuously and do not form a closed loop. There is a physical connection between the central and peripheral portions of the explosion-proof valve 7. In the event of a rupture in the explosion-proof valve 7, the connection between the central and outer portions of the explosion-proof valve 7 is achieved by the connection, improving safety after pressure release.

[0051] However, in some other embodiments, the groove depth of the groove 73 of the explosion-proof valve 7, which does not form a closed loop, may change gradually. By gradually changing the groove 73 from one end to the other of the explosion-proof valve 7, the opening pressure of the explosion-proof valve 7 can be reduced and the explosion performance can be improved. The specific depths of the deepest and shallowest parts of the groove depth may be designed according to the explosion pressure.

[0052] In one embodiment, the buffer groove 72 forms an annular groove that extends at least once around the circumference, and the notched groove 73 is installed on the bottom wall of at least one of the annular grooves that extends around the circumference.

[0053] The buffer groove 72 forms an annular groove that extends at least once around the circumference, creating a complete buffer zone around the vibration transmission path and exhibiting an excellent buffering effect.

[0054] Specifically, to improve the cushioning effect, multiple fitted annular grooves can be installed as needed. The notched groove 73 is installed on the bottom wall of one of the annular grooves, and the notched groove 73 can be selected to be installed on the bottom wall of the outermost cushioning groove 72, thereby ensuring a pressure release area and pressure release effect. It can be selected and set according to the battery capacity, the need for pressure release, etc., offering a high degree of flexibility.

[0055] In one embodiment, the shape of the buffer groove 72 matches the shape of the outer casing of the valve body 71.

[0056] The shape of the buffer groove 72 matches the shape of the outer casing of the valve body 71, resulting in excellent buffer consistency in all directions over 360 degrees and high reliability.

[0057] In one embodiment, a wrap edge 74 is formed on the edge of the valve body 71, either adjacent to the buffer groove 72 or spaced apart from the buffer groove 72. Optionally, to create a more compact structure, the wrap edge 74 is formed around the circumferential edge of the buffer groove 72.

[0058] In some other embodiments, provided that the pressure relief requirement is met, the buffer groove 72 may be spaced apart from the wrap edge 74 to improve buffer reliability.

[0059] The valve body 71 is welded to the edge of the through groove 41 on the positive electrode aluminum seat 4 via a lap edge 74 at its edge. The thickness of the lap edge 74 is designed according to the requirements for welding reliability, with greater thickness resulting in higher reliability.

[0060] In the embodiments of this application, in other embodiments, a battery cell assembly is provided as shown in Figures 10 to 16, and this battery cell assembly is Positive pole 1, Seal ring 2, Positive electrode lower plastic sheet 3, A positive electrode aluminum sheet 4 is provided with a through groove 41. Positive electrode upper plastic sheet 5, Riveted joint block 6, An explosion-proof valve 7 is installed in a sealed manner within the through groove 41, and It is equipped with a valve film 8.

[0061] Since the battery cell assembly includes the explosion-proof valve 7 according to this application, the buffer groove 72 of the explosion-proof valve 7 effectively absorbs vibration energy, effectively reducing the stress on the groove 73 under the conditions of battery cell production, pack assembly, and overall vehicle vibration, making it less likely for the groove 73 to fail due to fatigue fracture, and ensuring the reliability of the explosion-proof valve 7. Furthermore, since the groove 73 of the explosion-proof valve 7 is located on the wall surface of the buffer groove 72 on the valve body 71, the opening area of ​​the explosion-proof valve 7 is maximized, the pressure release speed is improved, and pressure can be quickly released when the battery cell experiences thermal runaway, reducing the risk of the battery cell exploding.

[0062] In another embodiment of the present invention, a battery comprising the above-described battery cell assembly is further provided.

[0063] Since the battery comprises the battery cell assembly according to this application, it has the same technical effects as the battery cell assembly and will not be explained again here. The safety and reliability of the battery are further improved, and the safety of new energy vehicles is greatly enhanced by the installation of the above-mentioned battery.

[0064] While embodiments of the present application have been described in conjunction with the attached drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present application, such modifications and variations being limited by the attached claims.

[0065] This application claims priority to the Chinese patent application filed with the China National Patent Office on 13 May 2024, application number 202421053457.4, with the title of the invention "Explosion-proof valve, battery cell assembly and battery," all of which are incorporated herein by reference. [Explanation of Symbols]

[0066] 1. Positive pole column 2. Seal ring 3. Plastic sheet at the bottom of the positive electrode 4. Positive electrode aluminum sheet 41. Through groove 5. Plastic sheet on top of the positive electrode 6. Riveted joint block 7. Explosion-proof valve 71. Valve body 72, buffer groove 73. Notched grooves 731, deep groove part 732, Shallow groove part 733, transition part 74. Wrap Edge 8. Valve film

Claims

1. A valve body (71) having an inner and outer side, A buffer groove (72) is installed in the valve body (71) and is recessed toward the inside of the valve body (71) to form an annular groove structure, An explosion-proof valve characterized by comprising: a notched groove (73) formed annularly on the bottom wall of the buffer groove (72) along the extending direction of the buffer groove (72).

2. The explosion-proof valve according to claim 1, characterized in that the grooved portion (73) forms a continuous closed loop, the grooved portion (73) includes a deep groove portion (731) and a shallow groove portion (732), and the residual thickness of the deep groove portion (731) is smaller than the residual thickness of the shallow groove portion (732).

3. The explosion-proof valve according to claim 2, characterized in that the transition between the deep groove portion (731) and the shallow groove portion (732) is by a step, or the transition between the deep groove portion (731) and the shallow groove portion (732) is smooth.

4. The explosion-proof valve according to claim 1, characterized in that the cross-sectional shape of the buffer groove (72) is U-shaped.

5. The explosion-proof valve according to claim 1, characterized in that the cross-sectional shape of the groove (73) is an inverted trapezoid.

6. The explosion-proof valve according to claim 2, characterized in that at least the cross-sectional shape of the deep groove portion (731) is an inverted trapezoid.

7. The explosion-proof valve according to claim 2, characterized in that the length of the shallow groove portion (732) accounts for 1 / 10 to 1 / 3 of the total length of the grooved portion (73).

8. The explosion-proof valve according to claim 1, characterized in that the grooves (73) are installed continuously and do not form a closed loop.

9. A positive electrode aluminum sheet (4) having a through groove (41), A battery cell assembly comprising: an explosion-proof valve (7) according to any one of claims 1 to 8, which is sealed and installed within the through groove (41).

10. A battery characterized by comprising the battery cell assembly described in claim 9.

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