Patent ID: 9028565
Filing Date: 2015-05-12
Classification: D01D,H01M,Y02E,Y10T

Abstract:
1. A method of making a composite separator for disposition between a negative electrode and a positive electrode in an electrochemical battery cell of a lithium ion battery, the method comprising: (a) providing a collector substrate that includes a collection face; (b) electrospinning a first non-woven polymer fiber mat onto the collection face of the collector substrate, the first non-woven polymer fiber mat comprising a fibrous web of one or more polymer fibers and having a top surface; (c) applying ceramic particles over the top surface of the first non-woven polymer fiber mat; and (d) electrospinning a second non-woven polymer fiber mat over the first non-woven polymer fiber mat and the ceramic particles to form a composite separator, the second non-woven polymer fiber mat comprising a fibrous web of one or more polymer fibers that are the same type as, or different from, the one or more polymer fibers in the first non-woven polymer fiber mat, wherein the composite separator includes a first major face provided by the first non-woven polymer fiber mat and a second major face provided by the second non-woven polymer fiber mat, the first and second major faces defining a thickness of the separator, and further comprising a first edge region adjacent to the first major face, a second edge region adjacent to the second major face, and an intermediate region between the first and second edge regions, the intermediate region comprising a greater weight percent of ceramic particles than each of the first and second edge regions based on the total weight of the ceramic particles and the one or more electrospun polymer fibers in each region.