Battery explosion valve

Abstract

The utility model discloses a battery explosion -proof valve, including the electric core explosion -proof valve subassembly, electric core explosion -proof valve subassembly includes electric core negative cover plate base plate, explosion -proof valve body, protection patch, sealing ring, pole, lower insulating sheet and riveting block, explosion -proof valve body adopts double parameter control mechanism, and through alloy solder layer is welded in the recess of electric core negative cover plate base plate, alloy solder layer can accurate adjustment melting point, high thermal conductivity, high mechanical strength and strong corrosion resistance according to thermal runaway parameter, to realize temperature -pressure double parameter collaborative control. In this way, through the special alloy solder realizes temperature -pressure double parameter collaborative control, effectively improves traditional explosion -proof valve control precision deficiency and life attenuation problem, explosion -proof valve body and alloy solder all have excellent electrolyte corrosion -resistant performance, can form stable passivation film in the nick area and welding interface, effectively suppress HF acid etching and fatigue crack propagation, ensure that explosion -proof valve is in the whole battery life cycle threshold parameter stability.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery safety technology, and in particular to a battery explosion-proof valve. Background Technology

[0002] As a core component of the battery safety system, the lithium battery explosion-proof valve's core function is to actively perform pressure relief operations when abnormal operating conditions occur inside the battery, thereby preventing explosions or fires. Currently, the mainstream lithium battery explosion-proof valve design in the industry generally uses a serrated, thin structure to achieve valve opening pressure regulation. However, this structure has three main technical bottlenecks: 1. Valve opening accuracy defects: Process fluctuations during stamping lead to inconsistent serration depths, causing a discrete distribution of burst pressure values, resulting in premature triggering or delayed initiation of the pressure relief action. 2. Cycle life degradation: The shell breathing effect during battery cycle charging and discharging causes stress concentration at the root of the serration, generating fatigue microcracks. Simultaneously, the corrosion of the serration area by the electrolyte (especially HF generated from the hydrolysis of LiPF6) further accelerates the degradation of burst pressure, leading to early failure or false triggering of the explosion-proof valve. 3. Thermal response hysteresis: A single valve body structure is difficult to adapt to localized thermal runaway scenarios. The time required for heat transfer to the fixed valve position is too long, and its response time lags significantly behind the critical time point of cell shell rupture.

[0003] Therefore, in order to solve the problems of insufficient control accuracy, lifespan degradation and thermal response delay of traditional solutions, there is an urgent need for a high-safety dual-threshold explosion-proof valve structure for batteries. Utility Model Content

[0004] To address the technical problems existing in the background art, this utility model proposes a battery explosion-proof valve.

[0005] This utility model proposes a battery explosion-proof valve, including a cell explosion-proof valve assembly. The cell explosion-proof valve assembly includes a cell negative electrode cover plate substrate, an explosion-proof valve body, a protective patch, a sealing ring, a terminal post, a lower insulating sheet, and a riveting block. The explosion-proof valve body adopts a dual-parameter control mechanism and is welded to the groove of the cell negative electrode cover plate substrate through an alloy solder layer. The alloy solder layer can precisely adjust the melting point, high thermal conductivity, high mechanical strength, and strong corrosion resistance according to thermal runaway parameters to achieve temperature-pressure dual-parameter coordinated control.

[0006] In this way, true dual-threshold collaborative control is achieved, the problem of lifespan degradation is solved, and the layout is flexible and highly adaptable.

[0007] Preferably, the alloy solder layer is made of bismuth-based alloy or indium-based alloy.

[0008] Thus, it possesses the characteristics of precisely adjustable melting point, high thermal conductivity, high mechanical strength, and strong corrosion resistance.

[0009] Preferably, the bismuth-based alloy is Bi57Sn42Ag1 or Bi58Sn42; the indium-based alloy is In52Sn48.

[0010] Thus, the volume shrinks rapidly during melting, causing the explosion-proof valve body 2 to rupture and release pressure within <3s.

[0011] Preferably, the explosion-proof valve body is made of aluminum alloy with a thickness of 0.1mm-0.3mm and has grooves on its surface with a residual thickness of 50-150μm.

[0012] Thus, it can withstand a static pressure of 0.8 MPa.

[0013] Preferably, the temperature threshold of the explosion-proof valve body 2 is 130±10℃, and the pressure threshold is 0.6-1MPa.

[0014] Thus, when the internal temperature of the battery rises to the melting point of the alloy solder (e.g., 130°C), the solder melts instantly, loses its strength, and shrinks. The explosion-proof valve body 2 is then pushed open under internal pressure, achieving rapid pressure relief. This mechanism is particularly effective against localized thermal runaway, reducing the response time to less than 3 seconds. Even if the temperature does not reach the threshold, if the internal pressure abnormally rises and exceeds the mechanical strength of the explosion-proof valve body 2 structure by 0.6-1.0 MPa, the explosion-proof valve body 2 will also crack along the grooves to release pressure. This dual protection ensures higher safety.

[0015] Preferably, the protective patch is fixed to the surface of the negative electrode cover plate substrate of the battery cell by adhesive backing.

[0016] This prevents mechanical damage and contamination during transportation and assembly.

[0017] Preferably, when applied to square battery cells, the explosion-proof valve body is disposed on one side of the battery top cover.

[0018] Preferably, when applied to blade-shaped battery cells, the explosion-proof valve body is symmetrically distributed on the pole sides at both ends of the battery cell.

[0019] In this way, a multi-level, three-dimensional safety protection system is formed, consisting of "dual triggering of the main explosion-proof valve by temperature and pressure + pressure triggering of the auxiliary pressure relief valve," which completely solves the problem of thermal response delay.

[0020] In summary, this utility model has the following beneficial effects: A special alloy solder is used to connect the explosion-proof valve body and the negative electrode cover plate substrate of the battery cell. This special alloy solder can precisely adjust its melting point, has high thermal conductivity, high mechanical strength, and strong corrosion resistance according to thermal runaway parameters. Through this special alloy solder, temperature and pressure dual-parameter coordinated control is achieved, effectively improving the problems of insufficient control accuracy and lifespan degradation in traditional explosion-proof valves. Both the explosion-proof valve body and the alloy solder have excellent resistance to electrolyte corrosion, and can form a stable passivation film in the scored area and welding interface, effectively inhibiting HF acid etching and fatigue crack propagation, ensuring the stability of the threshold parameters of the explosion-proof valve throughout the entire battery life cycle.

[0021] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing the position of the battery explosion-proof valve in Embodiment 2 of this utility model;

[0023] Figure 2 This is a schematic diagram of the explosion of the battery explosion-proof valve in Embodiment 2 of this utility model;

[0024] Figure 3 This is a cross-sectional schematic diagram of the positive electrode cover plate assembly according to Embodiment 2 of this utility model;

[0025] Figure 4 This is a schematic diagram of the negative electrode cover plate assembly according to Embodiment 2 of this utility model;

[0026] Figure 5 for Figure 4 Schematic diagram of the BB-direction cross section;

[0027] Figure 6 for Figure 5 Enlarged view of point C in the image.

[0028] In the picture:

[0029] 1. Battery cell negative electrode cover plate substrate; 2. Explosion-proof valve body; 3. Protective patch; 4. Sealing ring; 5. Terminal post; 6. Lower insulating sheet; 7. Riveting block; 8. Battery cell positive electrode cover plate substrate; 9. Auxiliary pressure relief valve. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0031] like Figure 1-6 As shown in the figure, the battery explosion-proof valve proposed in this embodiment includes a cell explosion-proof valve assembly. The cell explosion-proof valve assembly includes a cell negative electrode cover plate substrate 1, an explosion-proof valve body 2, a protective patch 3, a sealing ring 4, a terminal post 5, a lower insulating sheet 6, and a riveting block 7. The explosion-proof valve body 2 adopts a dual-parameter control mechanism and is welded to the groove of the cell negative electrode cover plate substrate 1 through an alloy solder layer. The alloy solder layer can accurately adjust the melting point, high thermal conductivity, high mechanical strength, and strong corrosion resistance according to the thermal runaway parameters to achieve temperature-pressure dual-parameter coordinated control.

[0032] Thus, a special alloy solder is used to connect the explosion-proof valve body 2 and the battery cell negative electrode cover plate substrate 1. This special alloy solder can be precisely adjusted according to the thermal runaway parameters, and has high thermal conductivity, high mechanical strength, and strong corrosion resistance. Through this special alloy solder, temperature and pressure dual parameter coordinated control is achieved, effectively improving the problems of insufficient control accuracy and lifespan decay of traditional explosion-proof valves. Its working mechanism is as follows: when the set temperature is reached, the welding material melts and starts to release pressure, quickly discharging gas and heat, solving the defect of delayed response under thermal runaway conditions in traditional solutions. Both the explosion-proof valve body 2 and the alloy solder have excellent resistance to electrolyte corrosion, and can form a stable passivation film in the etched area and welding interface, effectively inhibiting HF acid corrosion and fatigue crack propagation, ensuring that the threshold parameters of the explosion-proof valve remain stable throughout the entire battery life cycle.

[0033] Furthermore, the alloy solder layer is made of bismuth-based alloy or indium-based alloy. It features precisely adjustable melting point [the melting point can be precisely set within a specific temperature range (e.g., 130±10℃) according to the thermal runaway characteristics of different battery cells], high thermal conductivity [it can quickly conduct heat from inside the battery cell to the solder layer, shortening the temperature response time], high mechanical strength [under normal battery operating conditions, it can withstand an internal pressure of ≥0.6MPa together with the explosion-proof valve body, ensuring sealing reliability], and strong corrosion resistance [it can resist long-term corrosion from the battery's internal electrolyte system (e.g., LiPF6 / DMC / EC)].

[0034] Furthermore, the bismuth-based alloy is Bi57Sn42Ag1 or Bi58Sn42; the indium-based alloy is In52Sn48. Upon melting, the volume shrinks rapidly, causing the explosion-proof valve body 2 to rupture and release pressure within <3 seconds.

[0035] It should be noted that the negative electrode cover plate substrate 1 of the battery cell and the alloy solder layer work together to form a passivation film, which significantly improves the corrosion resistance to electrolytes [LiPF6 / DMC / EC, etc.].

[0036] In this embodiment, the explosion-proof valve body 2 is made of aluminum alloy with a thickness of 0.1mm-0.3mm and has grooves on its surface with a residual thickness of 50-150μm. This component can withstand a static pressure of 0.8MPa.

[0037] The explosion-proof valve body 2 has a temperature threshold of 130±10℃ and a pressure threshold of 0.6-1 MPa. When the internal temperature of the battery rises to the melting point of the alloy solder (e.g., 130℃), the solder melts instantly, loses its strength, and shrinks. Under the action of internal pressure, the explosion-proof valve body 2 is pushed open, achieving rapid pressure relief. This mechanism is particularly effective against localized thermal runaway, and the response time can be shortened to less than 3 seconds. Even if the temperature does not reach the threshold, if the internal pressure rises abnormally and exceeds the mechanical strength of the explosion-proof valve body 2 structure by 0.6-1.0 MPa, the explosion-proof valve body 2 will also crack along the groove to relieve pressure. This dual protection ensures higher safety.

[0038] It should be noted that the protective patch 3 is fixed to the surface of the negative electrode cover plate substrate 1 of the battery cell by adhesive backing to prevent mechanical damage and contamination during transportation and assembly.

[0039] Example 1: Blade Battery Application (When applied to blade-shaped cells, the explosion-proof valve body 2 is symmetrically distributed on the pole sides at both ends of the cell)

[0040] Structural composition: A circular groove is machined on the negative electrode cover plate substrate 1 of the battery cell. The explosion-proof valve body 2 is a circular aluminum alloy sheet, which is welded into the groove by a bismuth-based alloy solder layer (such as Bi57Sn42Ag1) to form an airtight seal. The protective patch 3 is attached to the outer surface of the negative electrode cover plate substrate 1 of the battery cell by high temperature resistant adhesive to prevent mechanical damage and contamination during transportation and assembly.

[0041] Key parameters: Explosion-proof valve body 2 thickness 0.2mm, scratch depth residual thickness 100μm, alloy solder melting point 130℃, this component can withstand a static pressure of 0.8MPa.

[0042] Working mechanism: When the battery experiences thermal runaway and the local temperature rapidly rises to 130°C, the alloy solder melts within 2 seconds. At this time, the internal pressure is usually higher than 0.3MPa, which quickly pushes open the explosion-proof valve body 2, which has lost its weld fixation, forming a large-area pressure relief channel.

[0043] If, for other reasons, the internal pressure reaches 0.8 MPa before the temperature, the explosion-proof valve body 2 will first tear at its weakest point, thus releasing the pressure.

[0044] Example 2: Application of square batteries (when applied to square cells, the explosion-proof valve body 2 is located on one side of the battery top cover)

[0045] For long, thin, square-shaped batteries, to solve the problem of long heat transfer paths:

[0046] Install the explosion-proof valve assembly at one end of the top cover along its length.

[0047] One or more auxiliary pressure relief valves 9 are additionally installed on the large side wall of the battery cell. These auxiliary pressure relief valves can be made of traditional etched aluminum diaphragms, and their pressure threshold can be slightly higher than that of the main explosion-proof valve body. This layout forms a multi-level, three-dimensional safety protection system of "main explosion-proof valve temperature / pressure dual trigger + auxiliary pressure relief valve pressure trigger", which completely solves the problem of thermal response delay.

[0048] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0049] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A battery explosion-proof valve, comprising a cell explosion-proof valve assembly, the cell explosion-proof valve assembly comprising a cell negative electrode cover plate substrate (1), an explosion-proof valve body (2), a protective patch (3), a sealing ring (4), an electrode post (5), a lower insulating sheet (6), and a riveting block (7), characterized in that, The explosion-proof valve body (2) adopts a dual-parameter control mechanism and is welded to the groove of the negative electrode cover plate substrate (1) of the battery cell through an alloy solder layer; the alloy solder layer can accurately adjust the melting point, high thermal conductivity, high mechanical strength and strong corrosion resistance according to the thermal runaway parameters, so as to achieve temperature-pressure dual-parameter coordinated control.

2. The battery explosion-proof valve according to claim 1, characterized in that, The alloy solder layer is made of bismuth-based alloy or indium-based alloy.

3. The battery explosion-proof valve according to claim 2, characterized in that, The bismuth-based alloy is Bi57Sn42Ag1 or Bi58Sn42; the indium-based alloy is In52Sn48.

4. The battery explosion-proof valve according to claim 1, characterized in that, The explosion-proof valve body (2) is made of aluminum alloy with a thickness of 0.1mm-0.3mm and has grooves on its surface with a residual thickness of 50-150μm.

5. The battery explosion-proof valve according to claim 4, characterized in that, The temperature threshold of the explosion-proof valve body (2) is 130±10℃, and the pressure threshold is 0.6-1MPa.

6. The battery explosion-proof valve according to claim 1, characterized in that, The protective patch (3) is fixed to the surface of the negative electrode cover plate substrate (1) of the battery cell by adhesive backing.

7. The battery explosion-proof valve according to claim 1, characterized in that, When applied to square battery cells, the explosion-proof valve body (2) is located on one side of the battery top cover.

8. The battery explosion-proof valve according to claim 1, characterized in that, When applied to blade-shaped battery cells, the explosion-proof valve body (2) is symmetrically distributed on the pole side at both ends of the battery cell.

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