Radiation Testing of Commercial Rechargeable Lithium Polymer Batteries for Small Satellite Applications

Abstract

Commercial off-the-shelf (COTS) electrical components are becoming of interest for small satellite applications due to their accessibility, good performance, and low cost. We quantify the performance of Lithium Polymer (LiPo) COTS batteries under irradiation to assess their reliability. LiPo battery cells with LiCoO2 cathodes, nominal voltages of 3.7 V, and rated capacities of 6000 mAh are irradiated with a 30 MeV proton beam from the Middle East Technical University Defocusing Beamline, which delivers a maximum of 73 krad primary dose. Results show protons cause short-term damage, resulting in up to 17% faster discharge rates, which decreases after six months depending on the cell’s position and primary and secondary deposited dose. Additionally, a consumption rate increase of up to 42% occurs for the cells under prolonged secondary irradiation (1.2 krad). The separating polypropylene layer undergoes thinning and discoloration mainly due to secondary particles like neutrons and gammas. Finally, the LiCoO2 cathode of two batteries show dried polyvinylidene fluoride surface build-up, both potentially caused by discharge in a radioactive environment. Damaged cells do not suffer leakage.