Li-Ion Cots Cells for Low Temperature Mars Landers

Abstract

This digest describes the work undertaken to develop a secondary Li-ion battery for use in European space exploration missions from Commercial off the Shelf (COTS) cells. The battery was required to operate at temperatures below −20°C and survive a freeze/thaw cycle. A previous paper [1] described the search for a suitable cell, and the initial data from the module life test. As the results from this testing were extremely promising, the project was extended to determine the module performance up to 720 Sols at −20°C. Very low temperature survivability tests were also performed on the selected cells with good results. Further work has therefore been carried out to determine the longer term effects following a freeze/thaw cycle. The final part of the project was to produce a performance model of the cells. Results from the simulations have been compared to test data for the selected cell type.