Explosion-proof separator for Li-ion secondary batteries
A battery separator for a lithium-ion secondary battery is a microporbus membrane with an adjuvant. The microporous membrane is made of a thermoplastic, and has a thickness of 25 μm or less. The adjuvant, in an effective amount, is mixed into the membrane or coated thereon. The adjuvant is a material adapted to reduce or eliminate energy concentrations around the separator. The energy concentration is sufficient to initiate a reaction of the components of the lithium ion secondary battery.
1 . A battery separator for a lithium-ion secondary battery comprises:
a microporous membrane, said membrane having a thickness of 25 μm or less, said membrane being made of a thermoplastic, and an effective amount of an adjuvant adapted to reduce or eliminate energy concentrations around the separator, said energy concentrations being sufficient to initiate a reaction between components of said lithium ion secondary battery, said adjuvant being mixed into said membrane or coated thereon.
2 . The battery separator of claim 1 wherein said thermoplastic being polyethylene or copolymers of polyethylene.
3 . The battery separator of claim 1 herein said lithium ion secondary battery components being selected from the group consisting of anode materials, cathode materials, electrolytes, and separators.
4 . The battery separator of claim 1 wherein said adjuvant being adapted to quench or to retard said energy's ability to initiate a reaction between said lithium ion secondary battery components.
5 . The battery separator of claim 4 wherein said adjuvant being selected from the group consisting of: phosphates, halogenated polyethylene wax, triazine derivatives, and combinations thereof.
6 . The battery separator of claim 5 wherein said phosphate comprises a triphenyl phosphate.
7 . The battery separator of claim 6 wherein said triphenyl phosphate being about 1-60% by weight of the membrane of a substituted triaryl phosphate.
8 . The battery separator of claim 5 wherein said halogenated polyethylene wax comprises between about 2-20% by weight of said membrane.
9 . The battery separator of claim 5 wherein said triazine derivative comprises between about 0.5-10% by weight of said membrane.
10 . The battery separator of claim 1 wherein said adjuvant being adapted to conduct away said energy.
11 . The battery separator of claim 10 wherein said adjuvant being selected from the group consisting of inorganic materials, carbon black, organic materials, and combinations thereof.
12 . The battery separator of claim 11 wherein said inorganic materials being selected from the group consisting of Al 2 O 3 , SiO 2 , TiO 2 , and combinations thereof.
13 . The battery separator of claim 11 wherein said inorganic material comprises about 1-40% by weight of said membrane.
14 . The battery separator of claim 11 wherein said carbon black comprises about 1-40% by weight of said membrane.
15 . The battery separator of claim 11 wherein said organic material being selected from the group consisting of polyaniline, polyacetylene, and combinations thereof.
16 . The battery separator of claim 1 wherein said adjuvant being adapted to decompose to a gas.
17 . The battery separator of claim 16 wherein said adjuvant being selected from the group consisting of tetrazole-based compounds, semicarbazide-based compounds, and combinations thereof.
18 . The battery separator of claim 17 wherein said adjuvant comprises about 1-40% by weight of said membrane.
19 . The battery separator of claim 20 wherein said adjuvant comprises about 10-30% by weight of said membrane.
20 . The battery separator of claim 17 wherein said tetrazole-based compound being 5-phenyl tetrazole.
21 . The battery separator of claim 17 wherein said semicarbazide-based compound being p-toluenesulfonyl semicarbazide.
22 . A lithium ion battery having the separator according to claim 1.