COMPOSITE SEPARATOR FOR ELECTROCHEMICAL CELL CAPABLE OF SUSTAINED SHUTDOWN

摘要

This invention provides a multi-layer article comprising a first electrode material, a second electrode material, and a porous separator disposed between and in contact with the first and the second electrode materials, wherein the porous separator comprises a nonwoven consisting essentially of a plurality of fibers of a fully aromatic polyimide. Also provided is a method for preparing the multi-layer article, and an electrochemical cell employing the same. A multi-layer article comprising a polyimide nonwoven with enhanced properties is also provided.

主权项

1. A multi-layer article comprising a first positive electrode material, a second negative electrode material, and a porous separator disposed between and in contact with the first and the second electrode materials, wherein the porous separator comprises a porous film (layer A) disposed in a face to face relationship with a non-woven fabric layer (layer B);
said non-woven fabric layer B having a mean fiber diameter of 3 μm or less, a mean pore size of 6 μm or less, and a porosity less than 60%; said porous film A having a thickness of 2 μm or greater and is a micro-porous polyolefin membrane having a mean flow pore size of less than or equal to 0.5 μm and a porosity of 30 to 60%;and wherein;
the B layer comprises a non-thermoplastic polymer present at a weight percentage of layer B of 50% or more; and wherein the thickness of the A layer plus the B layer combined is less than or equal to 50 microns.