CN-122025988-A - Explosion-proof valve for battery and preparation method and application thereof

Abstract

The invention relates to the technical field of battery explosion-proof valves, in particular to a battery explosion-proof valve, a preparation method and application thereof. The invention provides a battery explosion-proof valve, which comprises a first metal sheet layer, a low-melting-point hot melt adhesive film layer and a second metal sheet layer which are sequentially stacked from top to bottom, wherein the melting point of the low-melting-point hot melt adhesive film layer is 60-130 ℃, the material of the low-melting-point hot melt adhesive film layer comprises maleic anhydride modified polyolefin, and the polyolefin monomer for preparing the maleic anhydride modified polyolefin comprises propylene. The battery explosion-proof valve can improve the safety and reliability of the high-energy-density battery in use.

Inventors

• FU YOUHU
• DONG QINGSHAN
• FU YI

Assignees

• 昆山致信天城电子材料有限公司

Dates

Publication Date

20260512

Application Date

20260224

Claims (10)

1. 1. The battery explosion-proof valve is characterized by comprising a first metal sheet layer, a low-melting-point hot melt adhesive film layer and a second metal sheet layer which are sequentially stacked from top to bottom; The melting point of the low-melting-point thermosol film layer is 60-130 ℃; The material of the low-melting-point hot-melt adhesive film layer comprises maleic anhydride modified polyolefin; Polyolefin monomers from which the maleic anhydride modified polyolefin is prepared include propylene.
2. 2. The battery explosion-proof valve according to claim 1, wherein the grafting rate of maleic anhydride in the maleic anhydride modified polyolefin is 0.1-1.5%.
3. 3. The battery explosion-proof valve according to claim 1, wherein the weight average molecular weight of the maleic anhydride modified polyolefin is 20 to 40 ten thousand.
4. 4. The battery explosion protection valve as set forth in claim 1, wherein said polyolefin monomer further comprises one or more of ethylene, butene and octene.
5. 5. The battery explosion protection valve as set forth in claim 4, wherein said polyolefin monomer further comprises ethylene and butene; the mass ratio of the propylene to the ethylene to the butylene is (84-95): 1-10): 1-6.
6. 6. The battery explosion-proof valve according to any one of claims 1 to 5, wherein the thickness of the low melting point hot melt adhesive film layer is 10 to 1000 μm.
7. 7. The battery explosion-proof valve according to claim 1, wherein the thickness of the first metal sheet layer and the second metal sheet layer is independently 0.05-2 mm; The surfaces of the first metal sheet layer and the second metal sheet layer are of patterned structures; the first metal sheet layer and the second metal sheet layer are made of nickel sheets, copper nickel plating sheets, steel sheets, copper sheets or aluminum sheets independently.
8. 8. The battery explosion-proof valve as set forth in claim 1, wherein said first metal layer is a single piece and said second metal layer is a ring-shaped structure; the outer boundary dimension of the annular structure is greater than the dimension of the first metal layer; And the edge position of the second metal layer is connected to the steel shell of the lithium battery in a laser welding mode.
9. 9. The method for preparing the battery explosion-proof valve according to any one of claims 1 to 8, which is characterized by comprising the following steps: and sequentially overlapping the first metal sheet layer, the low-melting-point hot melt adhesive film layer and the second metal sheet layer together, and performing hot pressing to obtain the battery explosion-proof valve.
10. 10. The battery explosion-proof valve according to any one of claims 1 to 8 or the battery explosion-proof valve prepared by the preparation method according to claim 9 is applied to a high-energy-density lithium battery.

Description

Explosion-proof valve for battery and preparation method and application thereof Technical Field The invention relates to the technical field of battery explosion-proof valves, in particular to a battery explosion-proof valve, a preparation method and application thereof. Background Currently, with the increasing popularity of electronic products, lithium battery products are widely used in the fields of consumer electronics, vehicle-mounted and energy storage. In the market of lithium battery applications, there are products in which the battery case is a steel case, and the internal pressure is increased due to abnormal use during use, and the battery case is more destructive once explosion occurs. Therefore, an explosion-proof valve is generally mounted on a steel-shell battery, and the main purpose is to ensure safety by releasing pressure through the explosion-proof valve when high pressure is generated inside the battery. Currently available explosion-proof valves are mainly made by laser-pre-engraving "score lines" or a weak weld on the battery cover plate of a metal battery case. When the internal pressure increases and the pressure acting on the scored area exceeds the tensile strength of the material, the scored area will first fracture, forming a pressure relief channel. In addition, a ball valve type pressure release valve is provided, a small ball is placed in a ball valve seat and fixed by a spring or glue, when the pressure exceeds the pretightening force of the spring or the adhesive force of the glue, the small ball is jacked up, gas is discharged from a hole on the side edge, and after the pressure is reduced, the small ball can reset under the action of the spring. There is also a composite explosion-proof valve, a battery cover assembly integrating a PTC (positive temperature coefficient) which prevents an overcurrent and a CID (current termination device) which is a pressure sensitive mechanical device. Disclosure of Invention In view of the above, the invention aims to provide a battery explosion-proof valve, and a preparation method and application thereof. The battery explosion-proof valve can improve the safety and reliability of the high-energy-density battery in use. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a battery explosion-proof valve, which comprises a first metal sheet layer, a low-melting-point hot melt adhesive film layer and a second metal sheet layer which are sequentially stacked from top to bottom; The melting point of the low-melting-point thermosol film layer is 60-130 ℃; The material of the low-melting-point hot-melt adhesive film layer comprises maleic anhydride modified polyolefin; Polyolefin monomers from which the maleic anhydride modified polyolefin is prepared include propylene. Preferably, the grafting rate of the maleic anhydride in the maleic anhydride modified polyolefin is 0.1-1.5%. Preferably, the weight average molecular weight of the maleic anhydride modified polyolefin is 20-40 ten thousand. Preferably, the polyolefin monomer further comprises one or more of ethylene, butene and octene. Preferably, the polyolefin monomer further comprises ethylene and butene; the mass ratio of the propylene to the ethylene to the butylene is (84-95): 1-10): 1-6. Preferably, the thickness of the low-melting-point hot melt adhesive film layer is 10-1000 microns. Preferably, the thickness of the first metal sheet layer and the second metal sheet layer is independently 0.05-2 mm; The surfaces of the first metal sheet layer and the second metal sheet layer are of patterned structures; the first metal sheet layer and the second metal sheet layer are made of nickel sheets, copper nickel plating sheets, steel sheets, copper sheets or aluminum sheets independently. Preferably, the first metal sheet layer is a whole sheet, and the second metal sheet layer is an annular structure; the outer boundary dimension of the annular structure is greater than the dimension of the first sheet metal layer; and the edge position of the second metal sheet layer is connected to the steel shell of the lithium battery in a laser welding mode. The invention also provides a preparation method of the battery explosion-proof valve, which comprises the following steps: and sequentially overlapping the first metal sheet layer, the low-melting-point hot melt adhesive film layer and the second metal sheet layer together, and performing hot pressing to obtain the battery explosion-proof valve. The invention also provides the application of the battery explosion-proof valve in the high-energy density lithium battery or the battery explosion-proof valve prepared by the preparation method in the technical scheme. The invention provides a battery explosion-proof valve, which comprises a first metal sheet layer, a low-melting-point hot melt adhesive film layer and a second metal sheet layer which are sequentially stacked fro