A battery core explosion-proof valve and top cover structure

Abstract

The utility model provides a battery cell explosion-proof valve and top cover structure, which relates to the field of battery technology. The explosion-proof valve includes an explosion-proof plate, which includes a mounting portion and an explosion-proof portion. The explosion-proof portion is provided with a first protrusion, a second protrusion and an explosion-proof line. The first protrusion protrudes upward in a spherical shape, the second protrusion is arranged around the outer periphery of the first protrusion, and the explosion-proof line is arranged on the outer periphery of the second protrusion. The explosion-proof plate is applied to a top cover structure, which includes a cover plate, and the cover plate is evenly provided with a plurality of pole holes along the length direction. A mounting hole for installing the above-mentioned explosion-proof plate is provided between two adjacent pole holes. The utility model shortens the diffusion path of the reaction gas from the pole to the explosion-proof plate by providing two explosion-proof plates, thereby improving the explosion-proof control sensitivity of the battery; the first protrusion and the second protrusion ensure that the explosion-proof portion maintains structural stability when subjected to impact within the explosion-proof opening pressure, thereby avoiding loss of the explosion-proof function due to premature deformation.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an explosion-proof valve for a battery cell and a top cover structure. Background Art

[0002] The research and development and production of batteries must all take into account the safety standards of batteries. Explosion-proof valves are an essential safety line of defense for large-capacity batteries to prevent batteries from exploding after thermal runaway occurs. Existing battery cell top covers usually only have one explosion-proof valve in the middle, and the gas opening path is preset by etching explosion-proof lines with different patterns on the surface. Existing explosion-proof parts are mostly flat, and are prone to bulging and deformation after being subjected to thermal expansion pressure several times (not exceeding the pressure relief threshold), resulting in errors in the sensing of the actual gas pressure inside the battery cell. Furthermore, as the battery capacity increases, the heat generated by the battery is more concentrated on the pole than the interior, and as the distance between the winding core and the top cover is continuously reduced, the diffusion space of the thermal expansion gas of the battery cell is also reduced, and the gas diffusion transfer speed is far less than the local thermal runaway speed of the battery cell, resulting in the explosion-proof valve being unable to achieve timely sensing and pressure relief of the battery cell, and the battery cell has exploded. Utility Model Content

[0003] In order to overcome the defects of the prior art, the technical problem to be solved by the utility model is to propose a battery core explosion-proof valve and a top cover structure, adopting the following technical solutions:

[0004] The utility model provides an explosion-proof valve for an electric core, comprising an explosion-proof piece, wherein the explosion-proof piece comprises a mounting portion and an explosion-proof portion, wherein the explosion-proof piece is provided with a first protrusion, a second protrusion and an explosion-proof line at the explosion-proof portion; the first protrusion protrudes upward in a spherical shape, and the second protrusion is arranged around the outer periphery of the first protrusion; the explosion-proof line is arranged on the outer periphery of the second protrusion.

[0005] As a further improvement, it also includes a connecting portion, which is connected between the installation portion and the explosion-proof portion.

[0006] As a further improvement, the second protrusion is in a closed loop shape, and the protrusion direction of the second protrusion is consistent with that of the first protrusion.

[0007] As a further improvement, the cross section of the first protrusion is in an arc shape, and its radius is greater than the radius of the second protrusion.

[0008] As a further improvement, a groove used as an explosion-proof line is provided at the connection between the connecting portion and the mounting portion, and the depth of the groove is 40% to 80% of the thickness of the connection.

[0009] As a further improvement, a connection position for forming an open ring is provided between the beginning and the end of the groove, and the width of the connection position is 2 mm to 10 mm.

[0010] The utility model further provides a battery cell top cover structure, including a cover plate, wherein the cover plate is evenly provided with a plurality of pole holes along the length direction, and mounting holes are respectively provided between two adjacent pole holes, and a battery cell explosion-proof valve as described in any one of the above items is fixedly installed in the two mounting holes.

[0011] As a further improvement, the cover plate is provided with a reinforcement portion, the reinforcement portion is connected to the cover plate via a slope structure, and the mounting hole is provided on the reinforcement portion.

[0012] As a further improvement, the two sides of the reinforcement portion along the length direction are convex semicircular, and the cover plate is provided with the mounting hole at the center of the semicircle.

[0013] As a further improvement, a mounting groove is arranged around the periphery of the lower side of the mounting hole, and the mounting portion is fixed to the mounting groove by gluing or welding.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] Firstly, in the utility model, a plurality of pole holes are arranged on the cover plate, and mounting holes are respectively arranged at the three-divided points between two adjacent pole holes, and explosion-proof plates are fixedly installed in the mounting holes. This structure shortens the diffusion path of the reaction gas from the pole to the explosion-proof plate, effectively shortens the opening induction time of the explosion-proof plate, and prevents battery explosion caused by local decompression.

[0016] Secondly, in the utility model, there is a height difference between the installation part and the explosion-proof part of the explosion-proof plate, and the two are connected by a slope structure. The explosion-proof part is provided with a spherical crown-shaped first protrusion and an annular second protrusion. When thermal runaway occurs, the internal thermal expansion pressure impacts the first protrusion, and the inner wall of the first protrusion unloads the impact to the surroundings. The annular protrusion structure of the second protrusion further strengthens the axial pressure bearing capacity of the first protrusion and bears the impact unloaded by the first protrusion. Through the above structure, the anti-interference ability of the explosion-proof part is strengthened, and deformation caused by multiple small-scale impacts during long-term use is avoided, resulting in failure of pressure relief control.

[0017] Thirdly, a boss is stamped in the middle of the cover plate of the utility model, and the two sides of the boss are outwardly convex semicircles, and the mounting hole is arranged at the center of the semicircle, so as to maintain the stability of the explosion-proof plate under impact and ensure effective pressure relief control.

[0018] Fourthly, the utility model has an explosion-proof line etched on the edge of the explosion-proof part. When the explosion-proof piece is subjected to an impact exceeding the opening pressure, the explosion-proof line breaks to release the pressure, and a blank etching area of ​​2 to 10 mm is left to prevent the metal diaphragm from flying out after the explosion-proof piece is opened. This structure does not rely on a complex mechanical structure, but achieves the explosion-proof function through the structural characteristics of the groove, reducing the complexity of the design and the possibility of failure. The reserved connection position prevents the diaphragm from being opened and causing damage to the surrounding electrical environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the following is a brief introduction to the drawings required for use in the implementation mode. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2 It is a schematic diagram of the overall structure of the explosion-proof disk in the utility model;

[0022] Figure 3 It is a schematic diagram of the assembly of the utility model;

[0023] Figure 4 It is a front cross-sectional view of the utility model;

[0024] Figure 5 for Figure 4 The enlarged view of point A in the middle;

[0025] Figure 6 It is a top view of the explosion-proof disk in the utility model.

[0026] Reference numerals:

[0027] 1-cover plate; 2-pole hole; 3-mounting hole; 4-explosion-proof disk; 5-liquid injection hole;

[0028] 11- Strengthening Department;

[0029] 31-mounting slot;

[0030] 41-installation part; 42-explosion-proof part; 43-connection part; 44-explosion-proof line; 44a-connection position;

[0031] 421 - first protrusion; 422 - second protrusion. DETAILED DESCRIPTION

[0032] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the accompanying drawings:

[0033] In the description of the present invention, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. The orientation or position relationship indicated by the terms "portion", "side", "end", etc. is based on the orientation or position relationship shown in the drawings and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0034] like Figure 1 As shown, the present application provides a battery cell top cover structure, including a cover plate 1, which covers and is fixed to the upper end of the battery packaging shell, and is used to isolate the electrical environment inside the packaging shell from the external environment to ensure the normal operation of the battery. The cover plate 1 mentioned in this description is adapted to the shape of the packaging shell. For the convenience of explanation, the square lithium battery cell will be used as an example for explanation below. The cover plate 1 is evenly provided with a number of pole holes 2 along the length direction, and a number of mounting holes 3 are provided between two adjacent pole holes 2. The mounting holes 3 are used to fix and install the explosion-proof plate 4. The cover plate 1 is preferably made of a material with a certain hardness and strength, such as aluminum alloy. Preferably, two of the above-mentioned mounting holes 3 are provided between two adjacent pole holes 2, and the two mounting holes 3 are respectively provided at the three-division point between the two pole holes 2. The mounting hole 3 is circular, which is convenient for alignment and has good force uniformity.

[0035] Specifically, in order to increase the capacity of the battery cell, the battery currently makes full use of the internal space of the packaging shell, so that the space between the battery roll core and the top cover is reduced. This will directly lead to the narrowing of the diffusion channel of the gas generated by thermal expansion when the battery pole undergoes thermal runaway. In a narrower pipe, the thermal expansion gas molecules have an increased chance of colliding with the channel wall during transmission. This frequent collision not only leads to energy loss, but also causes the movement direction of the gas molecules to change multiple times, thereby slowing down the overall transmission speed of the gas. In addition, the narrow pipe limits the flow space of the gas molecules, making the flow of gas in the pipe more restricted, which will cause the thermal expansion gas to be unable to diffuse to the explosion-proof plate 4 in time. By setting two explosion-proof plates 4 between the two poles, the path length of the thermal expansion gas diffusion to the explosion-proof plate 4 is shortened, the induction time of the explosion-proof plate 4 opening is effectively shortened, and the sensitivity of the battery explosion-proof control is improved. Through the above structure, the risks that may arise when the battery pole undergoes thermal runaway can be better dealt with, and the reliability and safety of the battery system can be improved.

[0036] As a supplement, the following description is for the convenience of further understanding the structure of the cover plate 1. They are all conventional structures and are not shown in the drawings: the lower side of the cover plate 1 is fixed with a lower plastic, a positive pole column component and a negative pole column component. The pole column components include a fixing ring, a pole terminal, an integrally injected sealing ring and an insulating anti-rotation reinforcement ring. The lower plastic has a pole hole 2 at the position corresponding to the pole. The positive and negative pole column components partially match and cover the corresponding pole hole 2, and partially extend above the top surface of the top cover sheet.

[0037] like Figure 2 As shown, the explosion-proof piece 4 includes a mounting portion 41, a connecting portion 43 and an explosion-proof portion 42. The connecting portion 43 is connected between the mounting portion 41 and the explosion-proof portion 42, so that there is an up and down height difference between the mounting portion 41 and the explosion-proof portion 42; the explosion-proof portion 42 is provided with a first protrusion 421, a second protrusion 422 and an explosion-proof line 44; the first protrusion 421 protrudes upward in a spherical shape, and the second protrusion 422 is arranged around the outer periphery of the first protrusion 421; the explosion-proof line 44 is arranged on the outer periphery of the second protrusion 422.

[0038] In a specific embodiment, the mounting portion 41 is circular, and the connecting portion 43 is a sloped surface that slopes downward from the outside to the inside, so that the explosion-proof portion 42 is lower than the mounting portion 41. The cross section of the first protrusion 421 is arc-shaped, and the second protrusion 422 is a closed-loop arc-shaped protrusion arranged around the first protrusion 421. The radius of the first protrusion 421 is greater than the radius of the second protrusion 422. When the battery has thermal runaway, the internal thermal expansion pressure impacts the first protrusion 421, and the inner wall of the first protrusion 421 unloads the impact to the surrounding area. On the one hand, the second protrusion 422 enhances the bearing capacity of the first protrusion 421 against the axial force, and at the same time, it also bears the impact unloaded by the first protrusion 421. In daily operation of the battery, the chemical reaction between the electrolyte and the electrode produces gas, and the electrode heats up. Due to the thermal expansion effect, pressure is generated inside the battery. Usually, this pressure will remain within the normal range and will not cause thermal runaway, but it will still produce short-term shocks. These shocks are particularly frequent during the battery charge and discharge cycle. Although they do not exceed the explosion-proof threshold, they will have a certain impact on the explosion-proof structure. Through the above structure, it is ensured that the explosion-proof part 42 can remain stable when facing multiple shocks caused by the above situations, and will not deform prematurely due to repeated shocks and lose the explosion-proof function.

[0039] like Figure 3 As shown, a mounting groove 31 is arranged around the periphery of the lower side of the mounting hole 3 , and the mounting portion 41 of the explosion-proof disc 4 is fixedly arranged in the mounting groove 31 .

[0040] In a specific embodiment, an annular groove is provided along the edge of the lower side of the mounting hole 3 to form the above-mentioned mounting groove 31. The mounting portion 41 of the explosion-proof disk 4 is an annular plate matching the size of the groove. When installing, the mounting portion 41 is fitted into the mounting groove 31. Preferably, the mounting portion 41 is fixedly connected to the mounting portion 41 by welding. In addition, the fixed connection can also be performed by gluing or other methods.

[0041] like Figure 2 As shown, combined with Figure 4-Figure 6 , the connection between the connecting portion 43 of the explosion-proof plate 4 and the mounting portion 41 is provided with a groove as an explosion-proof line 44, which is formed by etching with a laser, a carving knife or a chemical solution, and the depth of the groove is 40% to 80% of the thickness of the connection. The specific depth can be selected according to the material of the explosion-proof plate 4, and is not specifically limited here. More specifically, the mounting portion 41, the connecting portion 43 and the explosion-proof portion 42 are integrally formed and have equal thickness. When the explosion-proof portion 42 is subjected to a pressure exceeding the explosion-proof opening threshold, the explosion-proof plate 4 breaks along the explosion-proof line 44 to release the pressure. The cross-sectional shape of the above-mentioned groove includes but is not limited to an inverted triangle, an inverted trapezoid, a lower semicircle, or other shapes that are easy to process, preferably a cross-sectional shape in which the width gradually increases from the bottom of the groove to the notch.

[0042] Further, such as Figure 6 As shown, the explosion-proof line 44 is reserved with a connection position 44a. The connection position 44a refers to a portion of the explosion-proof line 44 that is not etched. When the battery reaches a certain pressure inside due to thermal runaway, the explosion-proof piece 4 breaks along the explosion-proof line 44 and tilts relative to the cover plate 1. The explosion-proof part 42 and the cover plate 1 remain connected at the connection position 44a and will not be directly separated and opened, preventing the membrane from being opened and causing damage to the surrounding mechanical structure and electrical environment, thereby ensuring the safety performance of the explosion-proof piece 4 when it explodes. Preferably, the width of the connection position 44a is 2mm to 10mm, and the specific width can be selected according to the material of the explosion-proof piece 4, and is not specifically limited here.

[0043] like Figure 1 and Figure 3 As shown, the cover plate 1 is provided with a reinforcement portion 11 , which is connected to the cover plate 1 via a slope structure. The reinforcement portion 11 is provided with the above-mentioned mounting hole 3 , and the reinforcement portion 11 is also provided with a liquid injection hole 5 , which is located between the two mounting holes 3 .

[0044] In a specific embodiment, the middle portion of the cover plate 1 is stamped to form a boss, and the two sides of the boss along the length direction are outwardly convex semicircular, and the cover plate 1 is provided with the above-mentioned mounting hole 3 at the center of the semicircle.

[0045] The above description is only the preferred implementation of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A battery core explosion-proof valve, comprising an explosion-proof disc (4), the explosion-proof disc comprising a mounting portion (41) and an explosion-proof portion (42), characterized in that: The explosion-proof plate (4) is provided with a first protrusion (421), a second protrusion (422) and an explosion-proof line (44) at the explosion-proof portion (42); the first protrusion (421) protrudes upward in a spherical shape, and the second protrusion (422) is arranged around the outer periphery of the first protrusion (421); and the explosion-proof line (44) is arranged on the outer periphery of the second protrusion (422).

2. The battery core explosion-proof valve according to claim 1, characterized in that: It also includes a connecting portion (43), wherein the connecting portion (43) is connected between the mounting portion (41) and the explosion-proof portion (42).

3. The battery core explosion-proof valve according to claim 1, characterized in that: The second protrusion (422) is in a closed loop shape, and the protrusion direction of the second protrusion (422) is consistent with that of the first protrusion (421).

4. A battery core explosion-proof valve as claimed in claim 1 or 3, characterized in that: The cross section of the first protrusion (421) is in the shape of an arc, and its radius is greater than the radius of the second protrusion (422).

5. The battery core explosion-proof valve according to claim 2, characterized in that: A groove used as an explosion-proof line (44) is provided at the connection between the connecting portion (43) and the mounting portion (41), and the depth of the groove is 40% to 80% of the thickness of the connection.

6. The battery core explosion-proof valve according to claim 5, characterized in that: A connection position (44a) for forming an open ring is provided between the beginning and the end of the groove, and the width of the connection position (44a) is 2 mm to 10 mm.

7. A battery cell top cover structure, characterized in that: The invention comprises a cover plate (1), wherein the cover plate (1) is evenly provided with a plurality of pole holes (2) along the length direction, a plurality of mounting holes (3) are provided between two adjacent pole holes (2), and a battery cell explosion-proof valve as described in any one of claims 1 to 6 is fixedly installed in the plurality of mounting holes (3).

8. A battery cell top cover structure as claimed in claim 7, characterized in that: The cover plate (1) is provided with a reinforcement portion (11), the reinforcement portion (11) is connected to the cover plate (1) via a slope structure, and the mounting hole (3) is provided on the reinforcement portion (11).

9. A battery cell top cover structure as claimed in claim 8, characterized in that: The two sides of the reinforcement portion (11) along the length direction are outwardly convex semicircular, and the cover plate (1) is provided with the mounting hole (3) at the center of the semicircle.

10. The battery cell top cover structure according to claim 7, characterized in that: A mounting groove (31) is arranged around the periphery of the lower side of the mounting hole (3), and the mounting portion (41) is fixed to the mounting groove (31) by gluing or welding.

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