Battery explosion-proof valve plate and manufacturing method thereof

Abstract

The invention discloses a battery anti-explosion valve plate and a manufacturing method thereof. The manufacturing method comprises the following steps: taking a material of which the mechanical property meets requirements as an anti-explosion valve base material; an anti-explosion valve plate with anti-explosion nicks is obtained on the anti-explosion valve base material through stamping; and the anti-explosion valve plate is subjected to annealing treatment. According to the anti-explosion valve base material, material selection is conducted on the anti-explosion valve base material according to the force performance, the crystal structure of the anti-explosion valve plate in the area where the anti-explosion nicks are located is changed through annealing, grain size distribution is made to be uniform, the stress and hardness of the anti-explosion valve plate in the anti-explosion nick area are reduced, fluctuation of the bursting pressure of the anti-explosion valve plate can be reduced, and the anti-explosion valve plate has the good anti-explosion performance. And the anti-exposure valve plate reaches a stable explosion value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of secondary batteries, and particularly relates to a battery explosion-proof valve plate and a manufacturing method thereof. BACKGROUND

[0002] At present, the material of the battery explosion-proof valve plate (Vent) mainly adopts MFX2-O state aluminum, and is welded with a battery cover or a shell to form a battery safety valve. The structure can timely release pressure in extreme conditions such as battery thermal runaway, and significantly improves the safety protection level of vehicles and passengers. In order to ensure the reliability of the battery in extreme environments, high-strength corrosion-resistant materials are currently used to manufacture the shell and the battery cover, but the dissimilar metal welding of the battery explosion-proof valve plate with non-aluminum materials (such as stainless steel, titanium alloy, etc.) can cause the generation of interface brittle phase, galvanic corrosion and other problems, resulting in the decline of battery safety performance and the shortening of cycle life. SUMMARY

[0003] In view of the above problems of the prior art, the technical problem to be solved by the present application is to provide a battery explosion-proof valve plate and a manufacturing method thereof.

[0004] To solve the above technical problems, the present application provides the following technical solutions: A battery explosion-proof valve plate manufacturing method, comprising the following steps: S100, taking a material with required force performance as an explosion-proof valve base material; S200, obtaining an explosion-proof valve plate with explosion-proof notches on the explosion-proof valve base material by stamping; S300, annealing the explosion-proof valve plate.

[0005] Further, the surface roughness of the explosion-proof valve base material satisfies: Ra≤0.5 μm, Rz≤1 μm.

[0006] Further, in the S100 step, the explosion-proof valve base material is a titanium alloy material, and the force performance requirements are: tensile strength ≥240 MPa; yield strength 140 MPa-275 MPa; elongation 40%-50%; hardness 60HV-85HV.

[0007] Further, in the S100 step, the explosion-proof valve base material is a stainless steel material, and the force performance requirements are: tensile strength ≥480 MPa; yield strength ≥175-185 MPa; elongation ≥40%; hardness ≤187HV.

[0008] Further, the S200 step comprises the following sub-steps: S210, forming a groove on the explosion-proof valve base material; S220, Make the bottom of the groove bulge upward to form a convex part and an annular thinning transition area around the convex part; S230. Explosion-proof grooves are formed in the thinning transition zone by stamping to obtain an explosion-proof valve plate.

[0009] Furthermore, the thickness of the explosion-proof valve substrate is 0.15mm to 0.5mm; the thickness of the thinning transition zone is less than or equal to 60% of the thickness of the explosion-proof valve substrate; the residual thickness at the explosion-proof notch is 0.02mm to 0.08mm, and is less than or equal to 80% of the thickness of the thinning transition zone.

[0010] Furthermore, step S300 includes the following sub-steps: S310. Place the explosion-proof valve plate in the vacuum furnace and make the vacuum degree of the vacuum furnace reach 0.001Pa~0.1Pa; S320. Heat the vacuum furnace to the predetermined temperature and maintain the temperature for the predetermined time; S330. Argon or nitrogen gas is introduced into the vacuum furnace to accelerate cooling. When the pressure inside the furnace rises to greater than or equal to 0.2 kPa, the gas introduction is stopped, and cooling continues until the temperature of the explosion-proof valve plate is <100°C. Then, the explosion-proof valve plate is removed from the vacuum furnace.

[0011] Furthermore, the explosion-proof valve substrate is made of titanium alloy, and in step S320, the predetermined temperature range is 500℃~700℃, and the predetermined holding time ranges from 20min~40min; or The explosion-proof valve substrate is made of stainless steel. In step S320, the predetermined temperature range is 1000℃~1200℃, and the predetermined heat preservation time ranges from 90min~150min.

[0012] Furthermore, before annealing the explosion-proof valve plate, it must be cleaned. The cleaning process includes the following steps: S301. Use a high-concentration hydrocarbon cleaning solution to perform the first cleaning of the explosion-proof valve plate; S302. Use a low-concentration hydrocarbon cleaning solution to perform a second rinse on the explosion-proof valve plate; S303. Use pure water to rinse the explosion-proof valve plate to thoroughly remove any residual hydrocarbon cleaning solution on the explosion-proof valve plate; S304. Place the explosion-proof valve plate in a tunnel oven to dry it completely.

[0013] A battery explosion-proof valve plate is manufactured using the battery explosion-proof valve plate manufacturing method described in any of the above claims.

[0014] In this invention, the explosion-proof valve substrate is made of titanium alloy or stainless steel, consistent with the mainstream materials currently used in battery casings. This ensures that the material of the explosion-proof valve plate matches that of the battery casing, avoiding problems such as brittle phase formation and galvanic corrosion that can occur when welding dissimilar metals to the explosion-proof valve plate and the battery casing. By optimizing the annealing process parameters of the titanium alloy and stainless steel materials, the crystal structure of the explosion-proof valve plate in the area of ​​the explosion-proof markings can be altered, resulting in a uniform grain size distribution. This reduces the stress and hardness of the explosion-proof valve plate in the marking area, while also reducing fluctuations in the burst pressure of the explosion-proof valve plate. Furthermore, by selecting the explosion-proof valve substrate material based on its mechanical properties and improving the accuracy of the residual thickness of the explosion-proof markings by forming a thinning transition zone, the explosion-proof valve plate ultimately achieves a smaller and more stable burst value. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of an embodiment of the battery explosion-proof valve plate manufacturing method of the present invention.

[0016] Figure 2 This is a top view of the explosion-proof valve plate.

[0017] Figure 3 for Figure 2 A sectional view along line AA.

[0018] Figure 4 for Figure 3 Enlarged view of point B.

[0019] Figure 5 This is a flowchart of the cleaning process.

[0020] Figure 6 This is a flowchart for the annealing process.

[0021] The diagrams in the instruction manual are labeled as follows: Explosion-proof valve plate-1; Groove-2; Protrusion-3; Thinning transition zone-4; Explosion-proof groove-5. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0023] Please see Figure 1 , Figure 1This is a flowchart illustrating an embodiment of the battery explosion-proof valve plate manufacturing method of the present invention. The battery explosion-proof valve plate and its manufacturing method in this embodiment include the following steps: S100. Select a material that meets the required mechanical properties as the base material for the explosion-proof valve. In this embodiment, the base material is preferably a titanium alloy. Of course, the base material can also be stainless steel (e.g., 316L stainless steel) or other mainstream materials for battery casings. In this embodiment, experiments have shown that the mechanical properties of the same material can vary significantly, and mechanical properties such as tensile strength, yield strength, elongation, and hardness all have a certain impact on the performance of the battery explosion-proof valve plate 1. In order to meet the material flowability during stamping and ensure the subsequent service life of the explosion-proof valve plate 1, this embodiment studies the influence of the mechanical property indicators of different materials on the stamping process and the service life of the explosion-proof valve plate 1, and obtains the following two mechanical property requirements: (1) When the base material of the explosion-proof valve is titanium alloy, its mechanical performance requirements are as follows: Tensile strength ≥240MPa; yield strength 140MPa~275MPa; elongation 40%~50%; hardness 60HV~85HV.

[0024] (2) When the base material of the explosion-proof valve is 316L stainless steel, the mechanical performance requirements are as follows: Tensile strength ≥480MPa; yield strength ≥175~185MPa; elongation ≥40%; hardness ≤187HV.

[0025] The reason for using the above two materials for the explosion-proof valve substrate is as follows: To ensure the reliability of the battery in extreme environments, high-strength and corrosion-resistant materials are usually used instead of aluminum materials to manufacture the battery casing and battery cover. These non-aluminum materials are commonly titanium alloys and 316L stainless steel. In order to avoid problems such as the formation of brittle phases and galvanic corrosion caused by dissimilar metal welding between the battery casing or battery cover and the explosion-proof valve plate 1, which would lead to a decrease in battery safety performance and a shortened cycle life, it is necessary to use the same materials as the battery casing or battery cover to make the explosion-proof valve plate 1, that is, to use titanium alloys and 316L stainless steel.

[0026] The thickness d1 of the explosion-proof valve substrate using the above two materials is generally 0.15mm to 0.5mm, preferably 0.15mm to 0.3mm. For example, the thickness d1 of the explosion-proof valve substrate can be 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, etc. In this embodiment, the thickness d1 of the explosion-proof valve substrate is preferably 0.2mm.

[0027] Furthermore, since the residual thickness of the explosion-proof notch 5 in this embodiment is relatively small, to avoid excessive error in the residual thickness of the explosion-proof notch 5 due to the material itself, the surface roughness of the explosion-proof valve substrate is also tested when selecting it. A material with a surface roughness meeting the requirements is used as the explosion-proof valve substrate. The surface roughness of the explosion-proof valve substrate needs to meet the following requirements: Ra≤0.5μm, Rz≤1μm.

[0028] S200, please refer to Figure 2 , Figure 3 and Figure 4 An explosion-proof valve plate 1 with explosion-proof markings 5 ​​is obtained by continuous stamping on an explosion-proof valve substrate. This step may include the following sub-steps: S210. A groove 2 is formed on the explosion-proof valve substrate by stamping or extrusion, thereby reducing the thickness of the area where the groove 2 is located.

[0029] S220. The bottom of the groove 2 is raised upward to form a protrusion 3 and an annular thinning transition zone 4 surrounding the protrusion 3. By forming the protrusion 3 at the bottom of the groove 2, the stress caused by stamping or extrusion at the bottom of the groove 2 can be dispersed, reducing stress accumulation; the stretching effect during the formation of the protrusion 3 can also further reduce the thickness of the thinning transition zone 4. The thickness d2 of the thinning transition zone 4 is less than or equal to 60% of the thickness d1 of the explosion-proof valve substrate, preferably 40% to 60% of the thickness d1 of the explosion-proof valve substrate. In this embodiment, the thickness d2 of the thinning transition zone 4 is preferably 0.12 mm.

[0030] Because the material of the explosion-proof valve substrate is relatively thick, the explosion-proof groove 5 cannot be directly formed on the explosion-proof valve substrate in one go due to process limitations. In this embodiment, by first forming a thinning transition zone 4 with a relatively thin thickness, the explosion-proof groove 5 can be formed in the thinning transition zone 4 by one stamping, thereby improving the forming quality of the explosion-proof groove 5.

[0031] S230. Explosion-proof grooves 5 are formed in the thinning transition zone 4 by stamping to obtain the explosion-proof valve plate 1. The residual thickness d3 at the explosion-proof groove 5 is 0.02mm to 0.08mm, and is less than or equal to 80% of the thickness d2 of the thinning transition zone 4. For example, the residual thickness d3 at the explosion-proof groove 5 can be 80%, 70%, 60%, 50%, 40%, 30%, 20%, etc., of the thickness d2 of the thinning transition zone 4. Preferably, the residual thickness d3 at the explosion-proof groove 5 is 40% to 60% of the thickness d2 of the thinning transition zone 4. The residual thickness d3 at the explosion-proof groove 5 is the remaining thickness of the thinning transition zone 4 after stamping at the explosion-proof groove 5. For example, the residual thickness d3 at the explosion-proof groove 5 can be 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, etc. In this embodiment, the residual thickness d3 at the explosion-proof notch 5 is preferably 0.05 mm.

[0032] S300. Anneal the explosion-proof valve plate 1. During the aforementioned process, oil, dust, and other contaminants may accumulate on the surface of the explosion-proof valve plate 1. If these contaminants are not thoroughly cleaned, the following harmful effects may occur during the high-temperature annealing process: (1) Surface carburization and carbide formation. Oil stains and other contaminants are organic matter, mainly composed of hydrocarbons. In a high-temperature, oxygen-deficient annealing furnace (especially in a protective atmosphere or vacuum environment, although there is always a trace amount of oxygen in the furnace), these contaminants decompose into active carbon atoms. Active carbon atoms penetrate into the surface of the explosion-proof valve plate 1, leading to a local increase in carbon content. After annealing, the surface of the explosion-proof valve plate 1 becomes hard and brittle, and uneven hard spots may appear, or even network carbides may form. This will seriously affect subsequent machining and greatly reduce the fatigue strength and toughness of the parts.

[0033] (2) Surface oxidation and corrosion. Moisture and salt in contaminants (such as hand sweat and electrolytes in cutting fluid) will undergo a violent oxidation reaction with the metal matrix at high temperatures, or form low-melting-point eutectics, destroying the oxide protective film on the metal surface. This will lead to thickening of the oxide scale, forming an uneven oxide scale, resulting in increased material loss and a rough, uneven surface. The areas covered by contaminants will experience localized concentrated corrosion, forming pits or scars on the surface that are difficult to remove, rendering the explosion-proof valve plate 1 unusable.

[0034] (3) Affects furnace life and pollutes furnace environment. The pollutants carried by the explosion-proof valve plate 1 will volatilize or decompose at high temperature. The products will pollute the refractory materials in the furnace, reduce their heat preservation performance and service life, and also pollute the heating elements (such as electric furnace wire and silicon carbide rod), causing their resistance to change or even short circuit and burn out. It will also pollute the protective atmosphere in the furnace (such as nitrogen and hydrogen), causing the protective atmosphere to fail, and thus affecting the quality of other explosion-proof valve plates 1 in the same furnace.

[0035] (4) Affects the quality of subsequent processing. Defects such as oxide scale and carbides remaining on the surface after annealing will seriously affect the quality of subsequent surface treatments such as electroplating and spraying. The adhesion of the plating or coating to these defects is extremely poor, and problems such as blistering and peeling are prone to occur.

[0036] Therefore, before annealing the explosion-proof valve plate 1, it is generally necessary to clean it first; please refer to Figure 5 The cleaning process includes the following steps: S301. Use a high-concentration hydrocarbon cleaning solution to perform the first cleaning of the explosion-proof valve plate 1 to initially remove contaminants.

[0037] S302. Use a low-concentration hydrocarbon cleaning solution to perform a second rinse on the explosion-proof valve plate 1 to further reduce the residue of contaminants.

[0038] S303. Rinse the explosion-proof valve plate 1 with pure water to thoroughly remove the hydrocarbon cleaning solution remaining on the explosion-proof valve plate 1 during the first two cleaning steps.

[0039] S304. Place the explosion-proof valve plate 1 into a tunnel furnace for drying to ensure that the explosion-proof valve plate 1 is completely dry in order to facilitate subsequent annealing treatment.

[0040] Pre-annealing cleaning ensures uniform surface composition, removes all contaminants that may cause surface carburization or decarburization, and guarantees the uniformity of the overall chemical composition and microstructure of the workpiece after annealing. It also results in a uniform and clean metal surface, preventing defects such as oxide scale and corrosion pits, providing a good foundation for subsequent finishing or surface treatment. Furthermore, it maintains the cleanliness of the annealing furnace, ensuring its normal operation and process stability, and improving product yield. Therefore, pre-annealing cleaning is a crucial preliminary process for ensuring the quality and consistency of the final product.

[0041] Please see Figure 6 The annealing process may include the following sub-steps: S310. Place the explosion-proof valve plate 1 in the vacuum furnace and make the vacuum degree of the vacuum furnace reach 0.001Pa to 0.1Pa.

[0042] S320. Heat the vacuum furnace to a predetermined temperature and hold it at that temperature for a predetermined time. When the explosion-proof valve substrate is made of titanium alloy, the predetermined temperature range in this step is 500℃~700℃; for example, the predetermined temperature can be 500℃, 550℃, 600℃, 650℃, 700℃, etc., preferably 600℃. The predetermined holding time ranges from 20min to 40min; for example, the holding time can be 20min, 25min, 30min, 35min, 40min, etc., preferably 30min.

[0043] When the explosion-proof valve substrate is 316L stainless steel, the predetermined temperature range in this step is 1000℃~1200℃; for example, the predetermined temperature can be 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, etc., preferably 1100℃. The predetermined heat preservation time ranges from 90min to 150min; for example, the heat preservation time can be 90min, 100min, 110min, 120min, 130min, 140min, 150min, etc., preferably 120min, i.e., 2h.

[0044] S330. Argon or nitrogen gas is introduced into the vacuum furnace to accelerate cooling. When the pressure inside the furnace rises to greater than or equal to 0.2 kPa, the gas introduction is stopped, and the furnace is continuously cooled until the temperature of the explosion-proof valve plate 1 is <100°C. Then, the explosion-proof valve plate 1 is removed from the vacuum furnace.

[0045] Chromium is the core alloying element of stainless steel, and its "rust-proof" property comes from the dense chromium oxide passivation film that forms on the surface. Therefore, annealing of stainless steel has the following main functions: (1) Softening to eliminate work hardening. Stainless steel undergoes severe work hardening during cold working (such as stamping), resulting in increased strength and hardness, but a sharp decrease in plasticity and toughness, making subsequent processing difficult or even causing cracking. Annealing heats the stainless steel to above the recrystallization temperature, causing the elongated and broken grains to re-nucleate and grow, forming a new, equiaxed, stress-free grain structure. This eliminates work hardening and restores its excellent plasticity and toughness, thus avoiding large errors in the burst pressure of the explosion-proof valve plate 1.

[0046] (2) Eliminating internal stress and optimizing grain size. After cold working, stainless steel has residual stress inside the material, which can lead to dimensional instability or exacerbate stress corrosion cracking in corrosive environments. Annealing (especially stress-relief annealing, at a temperature below the recrystallization temperature) can cause atomic recovery, thereby relaxing and eliminating internal stress. By controlling the annealing temperature and time, uniform and fine grains can also be obtained, thereby further improving the overall mechanical properties of the material.

[0047] The properties of titanium alloys are highly dependent on their microstructure (α-phase, β-phase, and their morphology). Annealing of titanium alloys has the following main functions: (1) Eliminating residual stress. Titanium alloys have a low elastic modulus, which generates significant residual stress after cold working. These stresses significantly reduce the fatigue strength of titanium alloys, promote crack propagation, and cause deformation of parts during finishing or use. By performing stress-relief annealing at a temperature below the phase transformation point, internal stress can be eliminated without causing significant changes in the microstructure. This is crucial for ensuring the dimensional stability and safety of the explosion-proof valve plate 1.

[0048] (2) Improve plasticity and stabilize the microstructure to optimize comprehensive mechanical properties. After rapid cooling (e.g., air cooling) from the high-temperature β-phase region, titanium alloys (e.g., TC4) will obtain a non-equilibrium microstructure (e.g., martensitic α' phase or metastable α+β microstructure), which has high strength but poor plasticity and toughness, and the microstructure is unstable. Through recrystallization annealing or full annealing, the non-equilibrium metastable phase can be decomposed and transformed into a more stable and balanced α+β dual-phase microstructure, thereby significantly improving the plasticity, toughness and thermal stability of the alloy. By controlling the annealing temperature and time, the ratio, morphology and size of the α and β phases can also be adjusted, thereby obtaining a fine equiaxed microstructure and achieving the best match of strength, plasticity and toughness.

[0049] In this embodiment, the explosion-proof valve substrate is selected from titanium alloy or stainless steel, consistent with the mainstream materials currently used in battery casing manufacturing. This ensures that the material of the explosion-proof valve plate is the same as that of the battery casing, avoiding problems such as interface brittle phase formation and galvanic corrosion that can occur when dissimilar metals are welded between the explosion-proof valve plate 1 and the battery casing. By optimizing the annealing process parameters of the titanium alloy and stainless steel materials, the crystal structure of the explosion-proof valve plate in the area of ​​the explosion-proof groove can be changed, resulting in a uniform grain size distribution. This reduces the stress and hardness of the explosion-proof valve plate in the explosion-proof groove area, and also reduces the fluctuation of the explosion-proof valve plate's burst pressure. In addition, by selecting the explosion-proof valve substrate material based on its mechanical properties and improving the accuracy of the residual thickness of the explosion-proof groove by forming a thinning transition zone 4, the explosion-proof valve plate ultimately achieves a smaller and more stable burst pressure value.

[0050] This invention also discloses a battery explosion-proof valve plate. The battery explosion-proof valve plate of this embodiment can be manufactured using the battery explosion-proof valve plate manufacturing method described in any of the above embodiments. The material of the battery explosion-proof valve plate 1 in this embodiment can be consistent with the mainstream materials currently used in battery casing manufacturing, thereby avoiding problems such as interface brittle phase formation and galvanic corrosion that can occur when dissimilar metals are welded between the explosion-proof valve plate 1 and the battery casing. The explosion-proof valve plate 1 is manufactured using an optimized annealing process, which can reduce fluctuations in the burst pressure of the explosion-proof valve plate, enabling it to achieve a smaller and more stable burst pressure value.

[0051] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for manufacturing a battery explosion-proof valve plate, characterized in that, Includes the following steps: S100, Select a material whose mechanical properties meet the requirements as the base material for the explosion-proof valve; S200, An explosion-proof valve plate with explosion-proof markings is obtained by stamping on an explosion-proof valve substrate; S300, Anneal the explosion-proof valve plate.

2. The method for manufacturing a battery explosion-proof valve plate as described in claim 1, characterized in that, The surface roughness of the explosion-proof valve substrate satisfies: Ra≤0.5μm, Rz≤1μm.

3. The method for manufacturing a battery explosion-proof valve plate as described in claim 1, characterized in that, In step S100, the explosion-proof valve substrate is made of titanium alloy, and the required mechanical properties are as follows: Tensile strength ≥240MPa; yield strength 140MPa~275MPa; elongation 40%~50%; hardness 60HV~85HV.

4. The method for manufacturing a battery explosion-proof valve plate as described in claim 1, characterized in that, In step S100, the explosion-proof valve substrate is made of stainless steel, and the required mechanical properties are as follows: Tensile strength ≥480MPa; yield strength ≥175~185MPa; elongation ≥40%; hardness ≤187HV.

5. The method for manufacturing a battery explosion-proof valve plate as described in claim 1, characterized in that, Step S200 includes the following sub-steps: S210. A groove is formed on the explosion-proof valve substrate; S220, Make the bottom of the groove bulge upward to form a convex part and an annular thinning transition area around the convex part; S230. Explosion-proof grooves are formed in the thinning transition zone by stamping to obtain an explosion-proof valve plate.

6. The method for manufacturing a battery explosion-proof valve plate as described in claim 5, characterized in that: The thickness of the explosion-proof valve substrate is 0.15mm to 0.5mm; the thickness of the thinning transition zone is less than or equal to 60% of the thickness of the explosion-proof valve substrate; the residual thickness at the explosion-proof notch is 0.02mm to 0.08mm, and is less than or equal to 80% of the thickness of the thinning transition zone.

7. The method for manufacturing a battery explosion-proof valve plate as described in any one of claims 1 to 2, characterized in that, The S300 step includes the following sub-steps: S310. Place the explosion-proof valve plate in the vacuum furnace and make the vacuum degree of the vacuum furnace reach 0.001Pa~0.1Pa; S320. Heat the vacuum furnace to the predetermined temperature and maintain the temperature for the predetermined time; S330. Argon or nitrogen gas is introduced into the vacuum furnace to accelerate cooling. When the pressure inside the furnace rises to greater than or equal to 0.2 kPa, the gas introduction is stopped, and cooling continues until the temperature of the explosion-proof valve plate is <100°C. Then, the explosion-proof valve plate is removed from the vacuum furnace.

8. The method for manufacturing a battery explosion-proof valve plate as described in claim 7, characterized in that: The explosion-proof valve substrate is made of titanium alloy. In step S320, the predetermined temperature range is 500℃~700℃, and the predetermined holding time ranges from 20min~40min; or The explosion-proof valve substrate is made of stainless steel. In step S320, the predetermined temperature range is 1000℃~1200℃, and the predetermined heat preservation time ranges from 90min~150min.

9. The method for manufacturing a battery explosion-proof valve plate as described in claim 7, characterized in that, Before annealing the explosion-proof valve plate, it must be cleaned. The cleaning process includes the following steps: S301. Use a high-concentration hydrocarbon cleaning solution to perform the first cleaning of the explosion-proof valve plate; S302. Use a low-concentration hydrocarbon cleaning solution to perform a second rinse on the explosion-proof valve plate; S303. Use pure water to rinse the explosion-proof valve plate to thoroughly remove any residual hydrocarbon cleaning solution on the explosion-proof valve plate; S304. Place the explosion-proof valve plate in a tunnel oven to dry it completely.

10. A battery explosion-proof valve plate, characterized in that: It is manufactured using the battery explosion-proof valve plate manufacturing method as described in any one of claims 1 to 9.

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