SBIR-STTR Award

This project will demonstrate the safety of the Li/CuCl*2 battery system and develop components and cells for 270 V bipolar batteries for the power system for the More Electric Aircraft (MEA). The Li/CuCl*2/inorganic electrolyte system can presently deliver 226 w/kg and 181 Whr/kg for continuous discharge at up to 10 mA/cm*2 (3C) for over 500 deep cycles. Such performance is unmatched by any other known rechargeable system. The approach to demonstrate the safety of Li/CuCl*2 cells that will be undertaken during Phase I will be to subject hermetically welded prismatic D size Li/CuC1*2 cells in stainless steel cases to electrical abuse tests, such as >25 mA/cm*2 charging pulses lasting approximately equal to 20 s. The prismatic D cells will contain a 2.0 x 4.0 cm CuCl*2 electrode and a less than 400 psi pressure vent. A number of innovative materials and approaches will be evaluated to improve the Li electrode cycling efficiency. At least 30% of the Phase I effort will involve work to develop and evaluate experimental methods to greatly reduce the probability of leakage of the plastic ring on the perimeter of bipolar electrodes. Preliminary designs and cost estimates will be prepared for the size of 270 V bipolar Li/CuCl2 battery that best meets the requirements for a MEA.

Keywords:
RECHARGEABLE BATTER* LITHIUM BATTER* SECONDARY BATTER* LITHIUM HIGH POWER BATTER*

During the project prototype 9.6 cm diameter multi-cell bipolar Li/CuC12 all inorganic electrolyte batteries will be constructed and electrical performance and safety abuse tests carried out to evaluate the batteries for More Electric Aircraft (MEA) applications. Similar tests will be carried out with ~5.0 Ahr Li/CuCl2 prismatic cells in hermetically TIG welded steel cases with vents. The Li/CuCl2 system can presently deliver 226 W/kg and 181 Whr/hg for continuous discharge at up to 10.0 mA/cm2 (3C) for over 500 deep cycles. Such performance is unmatched by any other known rechrageable system. The Phase I project demonstrated the ability of fully charged Li/CuCl2 cells of a unique new design to withstand 30 s, 40 mA/cm2 charging pulses after 20 deep cycles without bursting a 400 psi vent. Approximately 60% of the Phase II effort will involve technical development to characterize and improve the ability of cells to withstand a variety of electrical, thermal and mechanical abuse conditions. Oxidation resistant shutdown separators will be tested and the design refined to prevent venting during short circuit or mechanical abuse. Innovative materials and designs will be developed and quality standards established to improve and assure superior cycling, electrical and safety performance.