Evaluation of the battery degradation factors for nano-satellites at LEO

Mission design and spacecraft design are challenging activities, which have to be carefully conducted in order to achieve a successful mission for a nano-satellite. In NewSpace, especially in the area of nano-satellites, there is a strong drive towards agile and quickly market deployed products. Typically, commercial-off-the-shelf (COTS) batteries are used and their manufacturers rarely provides specifically needed information about them. Thus, it is necessary for the nano-satellite developer to assess the battery performance and lifetime, on their own, in order to support an accurate mission/spacecraft design. In the proposed approach, the possible degradation factors and their feasible ranges were firstly considered, in order to limit the test requirements, and the selected degradation tests were performed. The scope of battery performance indicators analysis was limited to battery capacity and resistance. Their change and sensitivity were evaluated in relation to calendar aging, considering temperature and state-of-charge factors, and to cycling aging, considering temperature and cycle depth factors, and to radiation aging. Afterwards, the identified degradation rates were used for lifetime modelling. The resulting lifetime model had 0.69% and 0.81% root-mean-square-error, compared to the experiment, for the prediction of capacity and resistance, respectively.