Hydrophilic polymer coated microporous membranes capable of use as a battery separator
US4438185A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 3, 1982 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Sep 3, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention is directed to microporous membranes having a surfactant impregnated therein which is coated on at least one surface thereof with a polymer coating, such as cellulose acetate. The polymer coating possesses functional groups in the presence of an aqueous alkaline environment which permits it to undergo hydrogen bonding with water and to transport battery electrolyte through the coating by diffusion. The presence of the coating on the normally hydrophobic substrate membrane, when used in conjunction with a suitable surfactant, increases the wettability of the substrate membrane and thereby lowers its electrical resistance. The coating also serves to immobilize various soluble electrode derived ions at the coating-electrolyte interface thereby hindering their penetration into the pores of the substrate microporous membrane. Consequently, the plugging of the pores of the substrate membrane by these ions is substantially reduced thereby increasing the life of a battery in which said coated membranes are used as battery separators.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.