PENTA-LAYER BATTERY SEPARATOR

摘要

This invention provides a battery separator of improved resistance to splitting and puncture strength having five microporous membranes laminated together. The first, third, and fifth membranes are strength layers, and preferably are polypropylene. The second and fourth layers are shutdown layers, and preferably are polyethylene. The present invention is based on the discovery that a penta-layer separator having a construction of polypropylene-polyethylene-polypropylene-polyethylene-polypropylene has much greater resistance to splitting than a trilayer separator having a polypropylene-polyethylene-polypropylene construction with the same thickness.