| abstract |
Disclosed is a battery separator which has an insulating layer comprising a fibrous material having a service temperature limit of 150˚C or higher, an inorganic microparticle having an insulating property and a binder or, alternatively, which has an insulating layer comprising a porous layer composed of a thermally meltable resin, an inorganic microparticle having an insulating property and a binder. The battery separator has a water content per unit volume of 1 mg/cm3 or less, as measured after maintaining the battery separator under the atmosphere of 20˚C and 60% RH for 24 hours. By using the battery separator, it becomes possible to provide a lithium secondary battery which has good reliability and safety and is excellent in storage properties and charge-discharge cycle properties. |