Anti-explosion valve plate of power battery and preparation method of anti-explosion valve plate

Abstract

The invention discloses an explosion-proof valve plate of a power battery, the explosion-proof valve plate comprises a steel sheet and a copper sheet stacked on the inner side of the steel sheet, the steel sheet and the copper sheet are compounded into a whole, the explosion-proof valve plate is also provided with explosion-proof nicks, the explosion-proof nicks comprise a first nick and a second nick, the cross sections of the first nick and the second nick are groove-shaped, and the first nick and the second nick are arranged in a staggered manner. The first nick extends from the outer surface of the steel sheet to the inner side of the steel sheet and does not penetrate through the steel sheet, the second nick extends from the bottom of the first nick to the inner side of the copper sheet and does not penetrate through the copper sheet, and the distance between the bottom of the second nick and the inner side face of the copper sheet is larger than or equal to 0.03 mm and smaller than 0.08 mm. According to the explosion-proof valve plate, the copper sheet is arranged at the bottom of the steel sheet, the hard steel material and the soft copper material are compounded together, and the first nick and the second nick are arranged, so that the structural strength of the explosion-proof valve plate is considered, the precision of the explosion-proof valve plate is ensured, the valve opening sensitivity is improved, the safety of a power battery is ensured, and the service life of the power battery is prolonged. And the risk of liquid leakage caused by thinning the nicks of the explosion-proof valve plate is avoided.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to an explosion-proof valve sheet of a power battery and a preparation method thereof. Background Art

[0002] At present, lithium-ion or sodium-ion power batteries have gradually become mainstream products in the new energy industry due to their high energy density, good capacity consistency, and ability to support high-rate charge and discharge. Conventional power battery structures generally have only one injection hole, and their common problems are:

[0003] 1. The cylindrical power battery ternary system generally prefers a steel shell structure, which is not easy to deform when the abnormal internal pressure inside the battery increases. However, due to the hardness of the steel material, the explosion-proof valve opening pressure is generally high, and the valve opening consistency is poor, which brings safety risks to the battery;

[0004] 2. A few manufacturers have tried to reduce the opening pressure of the valve by notching and thinning the steel explosion-proof valve, which has resulted in a significant weakening of the structural strength and the risk of leakage after vibration and impact. Summary of the invention

[0005] The object of the present invention is to provide an explosion-proof valve sheet for a power battery and a preparation method thereof, so as to solve the problems of poor valve opening consistency and liquid leakage of the explosion-proof valve in the prior art.

[0006] In order to achieve the above-mentioned purpose, the present invention provides an explosion-proof valve sheet of a power battery, comprising a steel sheet and a copper sheet stacked on the inner side of the steel sheet, the steel sheet and the copper sheet are composited into one, and the explosion-proof valve sheet is also provided with explosion-proof notches, the explosion-proof notches comprising a first notch and a second notch, the cross-sections of the first notch and the second notch are both groove-shaped, the first notch extends from the outer surface of the steel sheet to the inner side of the steel sheet and does not penetrate the steel sheet, the second notch extends from the bottom of the first notch to the inner side of the copper sheet and does not penetrate the copper sheet, and the distance between the bottom of the second notch and the inner side surface of the copper sheet is greater than or equal to 0.03 mm and less than 0.08 mm.

[0007] Preferably, the first notch and the second notch are both in arc structures, and the central angle of the arc structures is greater than or equal to 325 degrees and less than or equal to 350 degrees.

[0008] Preferably, the distance between the bottom of the first notch and the inner side surface of the steel sheet is greater than or equal to 0.05 mm and less than or equal to 0.15 mm, and the thickness of the copper sheet is greater than or equal to 0.08 mm and less than or equal to 0.2 mm.

[0009] Preferably, the cross-sections of the first notch and the second notch are both U-shaped or V-shaped.

[0010] The present invention also provides a method for preparing an explosion-proof valve sheet of a power battery, comprising the following steps: providing a steel sheet, on which a first notch is formed, the cross-section of the first notch is groove-shaped, the first notch extends from the outer surface of the steel sheet to the inner side of the steel sheet and does not penetrate the steel sheet; providing a copper sheet, and compounding the copper sheet on the inner side of the steel sheet; forming a second notch at the bottom of the first notch, the cross-section of the second notch is groove-shaped, the second notch extends to the inner side of the copper sheet and does not penetrate the copper sheet, and the distance between the bottom of the second notch and the inner side of the copper sheet is greater than or equal to 0.03 mm and less than 0.08 mm.

[0011] Preferably, the first notch and the second notch are both in arc structures, and the central angle of the arc structures is greater than or equal to 325 degrees and less than or equal to 350 degrees.

[0012] Preferably, the first notch is formed by a first stamping process, and the second notch is formed by a second stamping process.

[0013] Preferably, the distance between the bottom of the first notch and the inner side surface of the steel sheet is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

[0014] Preferably, in the step of providing the copper sheet, the thickness of the copper sheet is greater than or equal to 0.08 mm and less than or equal to 0.2 mm.

[0015] Preferably, the cross-sections of the first notch and the second notch are both U-shaped or V-shaped.

[0016] Compared with the prior art, the present invention arranges a copper sheet at the bottom of the steel sheet, compounds the harder steel and the softer copper together and arranges a first notch and a second notch, thereby taking into account the structural strength of the explosion-proof valve sheet while ensuring the accuracy of the explosion-proof valve sheet and improving the valve opening sensitivity. It not only solves the problem of low valve opening sensitivity of the notch of the pure steel explosion-proof valve sheet, but also improves the valve opening consistency of the steel shell power battery explosion-proof valve sheet, ensures the safety of the power battery, and avoids the risk of leakage caused by simply thinning the notch of the explosion-proof valve sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural diagram of the explosion-proof valve plate and the power battery housing after welding in an embodiment of the present invention.

[0018] Figure 2 It is a structural diagram of an explosion-proof valve disc at one angle in an embodiment of the present invention.

[0019] Figure 3 This is a structural diagram of the explosion-proof valve disc from another angle in an embodiment of the present invention.

[0020] Figure 4 This is a cross-sectional view of the explosion-proof valve sheet in an embodiment of the present invention, in which the second notch is not provided.

[0021] Figure 5 for Figure 4 Enlarged view of point A in the middle.

[0022] Figure 6 2 is a cross-sectional view of the explosion-proof valve sheet in an embodiment of the present invention, where a second notch has been provided. DETAILED DESCRIPTION

[0023] In order to explain the technical content, structural features and achieved effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0024] like Figures 1 to 6 As shown, an embodiment of the present invention provides an explosion-proof valve sheet 1 of a power battery, comprising a steel sheet 11 and a copper sheet 12 stacked on the inner side of the steel sheet 11, the steel sheet 11 and the copper sheet 12 are composited into one, and an explosion-proof notch 13 is further provided on the explosion-proof valve sheet 1, the explosion-proof notch 13 comprises a first notch 131 and a second notch 132, the cross-sections of the first notch 131 and the second notch 132 are both groove-shaped, the first notch 131 extends from the outer surface of the steel sheet 11 to the inner side of the steel sheet 11 and does not penetrate the steel sheet 11, the second notch 132 extends from the bottom of the first notch 131 to the inner side of the copper sheet 12 and does not penetrate the copper sheet 12, and the distance t between the bottom of the second notch 132 and the inner side of the copper sheet 12 is greater than or equal to 0.03 mm and less than 0.08 mm. Specifically, the power battery can be a cylindrical power battery, and the explosion-proof valve sheet 1 is generally circular. The explosion-proof valve sheet 1 of the power battery can be arranged on the battery top cover, or on the shell bottom of the shell, or on an independent steel sheet 11, and then the steel sheet 11 is welded to the shell with openings at both ends of the power battery. In the embodiment of the present invention, Figure 1 As shown, the explosion-proof valve sheet 1 is arranged on an independent steel sheet 11 and is welded to the shell 2. A liquid injection hole 14 is also arranged in the middle of the explosion-proof valve sheet 1. The first notch 131 and the second notch 132 are arranged around the liquid injection hole 14. The size of the bottom of the first notch 131 is larger than the size of the top opening of the second notch 132, and the depth of the first notch 131 is larger than the depth of the second notch 132. The distance t between the bottom of the second notch 132 and the inner side surface of the copper sheet 12 is greater than or equal to 0.03 mm and less than 0.08 mm, which ensures that the bottom of the second notch 132 and the inner side surface of the copper sheet 12 have a thicker thickness, effectively avoiding the occurrence of power battery leakage. Moreover, the copper sheet 12 is softer than the steel sheet 11. Under the same thickness, the copper sheet 12 is easier to be punched open, and the valve opening sensitivity is higher.

[0025] The embodiment of the present invention arranges a copper sheet 12 at the bottom of the steel sheet 11, composites the harder steel and the softer copper together, and arranges a first notch 131 and a second notch 132, thereby taking into account the structural strength of the explosion-proof valve sheet 1, while ensuring the accuracy of the explosion-proof valve sheet 1 and improving the valve opening sensitivity, thereby solving the problem of low valve opening sensitivity of the pure steel explosion-proof valve sheet 1 due to the notch, and improving the valve opening consistency of the steel shell power battery explosion-proof valve sheet 1, thereby ensuring the safety of the power battery and avoiding the risk of leakage caused by blindly thinning the notch of the explosion-proof valve sheet 1.

[0026] In the embodiment of the present invention, the first notch 131 and the second notch 132 are both in arc structures, and the central angle of the arc structures is greater than or equal to 325 degrees and less than or equal to 350 degrees. Specifically, Figure 3 As shown, the central angle a of the portion without the explosion-proof notch 13 is greater than or equal to 10 degrees and less than or equal to 35 degrees, and the sum of the central angle a of the arc structure and the central angle a of the portion without the explosion-proof notch 13 is 360 degrees. Adjusting the central angle of the arc structure can help fine-tune the structural strength of the explosion-proof valve plate 1.

[0027] In the embodiment of the present invention, Figures 4 to 5 As shown, the distance T1 between the bottom of the first notch 131 and the inner side of the steel sheet 11 is greater than or equal to 0.05 mm and less than or equal to 0.15 mm, the thickness T2 of the copper sheet 12 is greater than or equal to 0.08 mm and less than or equal to 0.2 mm, and the distance t between the bottom of the second notch 132 and the inner side of the copper sheet 12 is greater than or equal to 0.03 mm and less than 0.08 mm. Specifically, the thickness of the steel sheet 11 is greater than 0.15 mm and less than or equal to 0.5 mm, the first notch 131 can be formed by a stamping process, and the distance T1 between the bottom of the first notch 131 and the inner side of the steel sheet 11 is greater than or equal to 0.05 mm and less than or equal to 0.15 mm, which ensures that the steel sheet 11 has a certain structural strength, and the second notch 132 is formed by secondary correction of the notch precision stamping on the basis of the first notch 131, so as to ensure the accuracy of the second notch 132, thereby ensuring the consistency of the opening of the explosion-proof valve sheet 1.

[0028] In the embodiment of the present invention, the cross-sections of the first notch 131 and the second notch 132 are both U-shaped or V-shaped. Specifically, Figures 5 and 6 As shown, the cross-sections of the first notch 131 and the second notch 132 are both U-shaped.

[0029] The embodiment of the present invention further provides a method for manufacturing the explosion-proof valve sheet 1 of the power battery, comprising the following steps:

[0030] S1. Provide a steel sheet 11, and form a first notch 131 on the steel sheet 11. The cross section of the first notch 131 is groove-shaped. The first notch 131 extends from the outer surface of the steel sheet 11 to the inner side of the steel sheet 11 and does not penetrate the steel sheet 11. Specifically, Figures 4 to 5 As shown, the thickness of the steel sheet 11 is greater than 0.15 mm and less than or equal to 0.5 mm. A first notch 131 can be pre-formed on the steel sheet 11. The first notch 131 does not penetrate the steel sheet 11, thereby ensuring that the steel sheet 11 has a certain structural strength.

[0031] S2, providing a copper sheet 12, and compounding the copper sheet 12 on the inner side of the steel sheet 11; specifically, as Figures 4 to 5 As shown, the steel sheet 11 and the copper sheet 12 can be formed by a copper-steel composite process, and specifically, can be formed by a physical metallurgical preparation process such as hot rolling to achieve a firm integration of the steel sheet 11 and the copper sheet 12 .

[0032] S3, a second notch 132 is formed at the bottom of the first notch 131, the cross section of the second notch 132 is groove-shaped, the second notch 132 extends to the inner side of the copper sheet 12 and does not penetrate the copper sheet 12, and the distance t between the bottom of the second notch 132 and the inner side surface of the copper sheet 12 is greater than or equal to 0.03 mm and less than 0.08 mm. Specifically, as Figure 6 As shown, the size of the bottom of the first notch 131 is larger than the size of the top opening of the second notch 132, the depth of the first notch 131 is greater than the depth of the second notch 132, and there is a thicker thickness between the bottom of the second notch 132 and the inner side surface of the copper sheet 12, which effectively avoids the occurrence of power battery leakage.

[0033] In the embodiment of the present invention, the explosion-proof valve sheet 1 of the power battery can be arranged on the battery top cover, or on the shell bottom of the shell, or on an independent steel sheet 11, and then the steel sheet 11 is welded to the shell with openings at both ends of the power battery. In the embodiment of the present invention, Figure 1 As shown, the explosion-proof valve plate 1 is arranged on an independent steel plate 11 and is welded to the housing 2 . A liquid injection hole 14 is also arranged in the middle of the explosion-proof valve plate 1 . The first notch 131 and the second notch 132 are arranged around the liquid injection hole 14 .

[0034] The embodiment of the present invention first sets a first notch 131 on the steel sheet 11 and the first notch 131 does not penetrate the steel sheet 11, and then composites the steel sheet 11 with the copper sheet 12 and sets a second notch 132, so that the preparation method of the explosion-proof valve sheet 1 in the embodiment of the present invention not only takes into account the structural strength of the explosion-proof valve sheet 1, but also ensures the accuracy of the explosion-proof valve sheet 1 and improves the valve opening sensitivity, which not only solves the problem of low valve opening sensitivity of the pure steel explosion-proof valve sheet 1 due to the notch, but also improves the valve opening consistency of the steel shell power battery explosion-proof valve sheet 1, ensures the safety of the power battery, and avoids the risk of leakage caused by blindly thinning the notch of the explosion-proof valve sheet 1.

[0035] In the embodiment of the present invention, the first notch 131 is formed by a first stamping process, and the second notch 132 is formed by a second stamping process. Specifically, the distance T1 between the bottom of the first notch 131 and the inner side surface of the steel sheet 11 is greater than or equal to 0.05 mm and less than or equal to 0.15 mm. Therefore, the depth of the first notch 131 is relatively deep, and it can be rough-processed by the first stamping process. The precision of the first stamping process is relatively low. The equipment and stamping dies of the first stamping process and the second stamping process are different. The first stamping process is a rough stamping process, and the second stamping process is a fine stamping process. For example, the first stamping process can use pneumatic equipment and pneumatic dies. Due to factors such as air source fluctuations and fast speed, it can only be used for rough stamping. The second stamping process can use hydraulic equipment with stable pressure and slow speed, which is suitable for fine stamping.

[0036] Furthermore, in step S2, in the step of providing the copper sheet 12, the thickness T2 of the copper sheet 12 is greater than or equal to 0.08 mm and less than or equal to 0.2 mm.

[0037] In the embodiment of the present invention, the cross-sections of the first notch 131 and the second notch 132 are both U-shaped or V-shaped, which makes it easier to shape the first notch 131 and the second notch 132 .

[0038] The embodiment of the present invention performs explosion-proof valve pre-scoring, copper-steel compounding, secondary correction scoring, and arc structure center angle control on the steel sheet 11 of the power battery with a steel shell structure, thereby achieving: first, a first score 131 with a relatively thin thickness is punched on the steel sheet 11, and then the steel sheet 11 and the copper sheet 12 are compounded, and finally, the copper-steel composite sheet is stamped and cut, and a secondary correction scoring is performed at the position of the first score to form a second score 132; controlling the center angle of the arc structure can assist in fine-tuning the structural strength of the explosion-proof valve; and finally, the steel sheet 11 is punched and the copper sheet 12 is compounded, and finally, the copper-steel composite sheet is punched and cut, and a second correction scoring is performed at the position of the first score to form a second score 132; controlling the center angle of the arc structure can assist in fine-tuning the structural strength of the explosion-proof valve; and finally, the steel sheet 11 is punched and the copper sheet 12 is compounded, and finally, the copper-steel composite sheet is punched and cut, and ... Finally, the relatively hard steel sheet 11 and the relatively soft copper sheet 12 are compounded together; the first notch 131 of the steel explosion-proof valve sheet 1 takes into account the structural strength of the explosion-proof valve sheet 1 during the later stamping process; the secondary stamping correction notch, i.e., the second notch 132, ensures the accuracy of the explosion-proof valve sheet 1 and improves its valve opening sensitivity, which not only solves the problem of low valve opening sensitivity of pure steel explosion-proof valve notches, but also improves the consistency of valve opening of steel shell battery explosion-proof valves, ensures the safety of the battery, and avoids the risk of leakage caused by simply thinning the notches of the explosion-proof valves.

[0039] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. An explosion-proof valve sheet for a power battery, characterized in that: It includes a steel sheet and a copper sheet stacked on the inner side of the steel sheet, the steel sheet and the copper sheet are composited into one, and an explosion-proof notch is also provided on the explosion-proof valve sheet, the explosion-proof notch includes a first notch and a second notch, the cross-sections of the first notch and the second notch are both groove-shaped, the first notch extends from the outer surface of the steel sheet to the inner side of the steel sheet and does not penetrate the steel sheet, the second notch extends from the bottom of the first notch to the inner side of the copper sheet and does not penetrate the copper sheet, and the distance between the bottom of the second notch and the inner side of the copper sheet is greater than or equal to 0.03 mm and less than 0.08 mm.

2. The explosion-proof valve sheet of the power battery according to claim 1, characterized in that: The first notch and the second notch are both in arc structures, and the central angles of the arc structures are both greater than or equal to 325 degrees and less than or equal to 350 degrees.

3. The explosion-proof valve sheet of the power battery according to claim 1, characterized in that: The distance between the bottom of the first notch and the inner side surface of the steel sheet is greater than or equal to 0.05 mm and less than or equal to 0.15 mm, and the thickness of the copper sheet is greater than or equal to 0.08 mm and less than or equal to 0.2 mm.

4. The explosion-proof valve sheet of the power battery according to claim 1, characterized in that: The cross sections of the first notch and the second notch are both U-shaped or V-shaped.

5. A method for preparing an explosion-proof valve sheet for a power battery, characterized in that: The steps include: Providing a steel sheet, on which a first notch is formed, wherein the cross section of the first notch is groove-shaped, and the first notch extends from the outer surface of the steel sheet to the inner side of the steel sheet and does not penetrate the steel sheet; Providing a copper sheet, and compounding the copper sheet on the inner side of the steel sheet; A second notch is formed at the bottom of the first notch. The cross-section of the second notch is groove-shaped. The second notch extends toward the inner side of the copper sheet and does not penetrate the copper sheet. The distance between the bottom of the second notch and the inner side surface of the copper sheet is greater than or equal to 0.03 mm and less than 0.08 mm.

6. The method for preparing the explosion-proof valve sheet of the power battery according to claim 5, characterized in that: The first notch and the second notch are both in arc structures, and the central angles of the arc structures are both greater than or equal to 325 degrees and less than or equal to 350 degrees.

7. The method for preparing the explosion-proof valve sheet of a power battery according to claim 5, characterized in that: The first notch is formed by a first stamping process, and the second notch is formed by a second stamping process.

8. The method for preparing the explosion-proof valve sheet of a power battery according to claim 6, characterized in that: The distance between the bottom of the first notch and the inner side surface of the steel sheet is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

9. The method for preparing the explosion-proof valve sheet of a power battery according to claim 7, characterized in that: In the step of providing a copper sheet, the thickness of the copper sheet is greater than or equal to 0.08 mm and less than or equal to 0.2 mm.

10. The method for preparing the explosion-proof valve sheet of a power battery according to claim 9, characterized in that: The cross sections of the first notch and the second notch are both U-shaped or V-shaped.

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