Lithium storage device with improved safety architecture
Improvements in the structural components and physical characteristics of lithium battery articles are provided. Standard lithium ion batteries, for example, are prone to certain phenomena related to short circuiting and have experienced high temperature occurrences and ultimate firing as a result. Structural concerns with battery components have been found to contribute to such problems. Improvements provided herein include the utilization of thin metallized current collectors (aluminum and/or copper, as examples), high shrinkage rate materials, materials that become nonconductive upon exposure to high temperatures, and combinations thereof. Such improvements accord the ability to withstand certain imperfections (dendrites, unexpected electrical surges, etc.) within the target lithium battery through provision of ostensibly an internal fuse within the subject lithium batteries themselves that prevents undesirable high temperature results from short circuits. Battery articles and methods of use thereof including such improvements are also encompassed within this disclosure.
1 . An energy storage device comprising an anode, a cathode, at least one separator present interposed between said anode and said cathode, at least one liquid electrolyte, and at least one current collector in contact with at least one of said anode and said cathode, wherein said at least one current collector has a top surface and a bottom surface; wherein said at least one separator is of a polymeric, ceramic, or nonwoven structure; wherein said at least one current collector comprises a polymer substrate exhibiting an areal density of at most 20 g/m 2 having a conductive coating on both surfaces thereof; wherein said at least one current collector further exhibits the capability to carry a current density when operating normally along a horizontal current pathway; and wherein said at least one separator does not exhibit a break therein when exposed to a temperature of 180° C. nor exhibit shrinkage in excess of 20% at 180° C. when subjected to the shrinkage test described in NASA TM—2010-216099 section 3.5.
2 . The energy storage device of claim 1 wherein said polymer substrate of said at least one current collector exhibits a porosity of at most 60%.