Lithium energy storage device with internal fuse
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 a sealed energy storage device container housing an anode, a cathode, at least one polymeric or fabric separator present between said anode and said cathode, at least one current collector in contact with at least one of said anode and said cathode and not in contact with said at least one separator, and liquid electrolytes; wherein said current collector comprises a conductive material coated on a polymeric material substrate, wherein said current collector exhibits the ability to carry a current density when operating normally along a current pathway horizontally along said current collector, wherein said current collector is unable to support a current through a point contact on the surface of the current collector, wherein said polymeric material substrate of said current collector exhibits heat shrinkage at 200° C. of at least 5%, and wherein said energy storage device exhibits no appreciable current pathway when subject to a short circuit.
2. The energy storage device of claim 1 wherein said current along the horizontal pathway is at least 0.1 A/cm, and said current through the point contact is at most 5 A/mm 2 .
3. The energy storage device of claim 1 wherein said current collector exhibits a thickness of less than 20 microns with resistance less than 1 ohm/square.
4. The energy storage device of claim 3 wherein said conductive material exhibits a total thickness of less than 5 microns.
5. The energy storage device of claim 3 wherein said current exhibits a conductivity of between 1 mOhm/square and 1 ohm/square.
6. The energy storage device of claim 1 wherein said device further comprises a separator, said separator exhibiting a heat shrinkage of less than 5% after 1 hour at 200° C.
7. The energy storage device of claim 3 wherein said device further comprises a separator, said separator exhibiting a heat shrinkage of less than 5% after 1 hour at 200° C.