Failure mode analysis of lithium ion batteries operated for low Earth orbit CubeSat applications

摘要

Three types of 18-65 cylindrical lithium-ion cells with different positive active materials (NCA - nickel cobalt aluminium, NMC - nickel manganese cobalt, LFP - lithium iron phosphate), negative active material graphite average particle sizes (2 - 30 mu m) and electrode designs (high power, high energy) were tested using an ac-celerated low earth orbit (LEO) CubeSat power profile cycle. Each design yields a unique energy density, power capability and cycle life. Each cell type was tested in a 3P group configuration at 10 degrees C in atmospheric pressure (101 kPa-abs) and under vacuum (0.2 kPa-abs). Cell groups were operated in their respective pressure condition until they failed to successfully execute the accelerated LEO cycle. In atmospheric pressure and vacuum, both NMC groups failed due to internal resistance (IR) growth. The atmospheric pressure NCA group failed due to excessive internal gas build-up triggering the current interrupt device (CID) to electrically disconnect. The NCA group in vacuum failed from both IR growth and capacity degradation. The LFP groups both in atmospheric pressure and vacuum have completed approximately 5078 LEO cycles or 2800 equivalent cycles of initial measured coulombic capacity and are still operational with 19% and 21% capacity degradation from their initial measured coulombic capacity, respectively.