A document discusses a thin layer of composite material, made from nano scale particles of nickel and Teflon, placed within a battery cell as a layer within the anode and/or the cathode. There it conducts electrons at room temperature, then switches to an insulator at an elevated temperature to prevent thermal runaway caused by internal short circuits. The material layer controls excess currents from metal-to-metal or metal-to-carbon shorts that might result from cell crush or a manufacturing defect.
The use of recently available nanoscale particles of nickel and Teflon permits an improved, homogenous material with the potential to be finetuned to a unique switch temperature, sufficiently below the onset of a catastrophic chemical reaction. The smaller particles also permit the formation of a thinner control film layer (<40 μm), which can be incorporated into commercial high-rate lithium primary and secondary cells. This innovation increases safety for high-rate batteries, thus preventing injury to nearby personnel and equipment.
This work was done by Robert C. McDonald, Shelly L. Van Blarcom, and Katherine E. Kwasnik of Giner, Inc. for Johnson Space Center.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:
Robert C. McDonald, PhD
89 Rumford Ave.
Newton, MA 02466
Phone No.: (781) 529-0530