APPARATUS FOR PINHOLE DETECTION AND PROCESS FOR IMPROVING YIELD IN THE MANUFACTURE OF BATTERIES

摘要

APPARATUS FOR PINHOLE DETECTION AND PROCESS FOR IMPROVING YIELD IN THE MANUFACTURE OF BATTERIES This invention pertains to microporous plastic films and to methods of inspecting such films. A significant number of rechargeable lithium batteries can be defective as fabricated and must be rejected. Flaws in the microporous polyolefin film separator, consisting of pinholes ?10 .mu.m in size, can be a cause for many defective cells. A novel apparatus and process is disclosed to detect the rare occurrence of pinholes over large areas in microporous polyolefin film separators used in rechargeable lithium batteries to improve battery yield.