Thermo-Electrochemical Mechanisms of Lithium Ion Battery Assemblies for Human Space Flight Applications
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Advanced energy storage and power management systems designed through rigorous materials selection, testing and analysis processes are essential to ensuring mission longevity and success for human space flight applications. Lithium ion (Li-ion) batteries provide superior performance characteristics, low mass and energy dense solutions. These features lead to the growing utilization of Li-ion technology for rockets, space exploration vehicles and satellites. Knowing that efficiency and survivability are influenced by temperature and that thermal safety concerns (i.e. thermal runaway) impede the utilization of Li-ion technology for human space flight applications, this dissertation focuses on the thermo-electrochemical mechanisms of Li-ion batteries. Test and analysis techniques developed here support the design of safe Li-ion battery assemblies.
Current finite element simulation methods support detailed analysis of thermo-electrochemical processes; however, said software packages do not maintain capabilities to incorporate the influence of thermal radiation driven orbital environments. In this dissertation, we couple existing thermo-electrochemical models of Li-ion battery local heat generation with specialized radiation analysis software, Thermal Desktop. The unique capability gained by employing Thermal Desktop is further demonstrated by simulating Li-ion battery thermal performance in example orbital environments exterior to a small satellite. Results provide demonstration of Li-ion battery thermo-electrochemical performance in space environments.
Experimental characterization of thermal runaway energy release with accelerated rate calorimetry supports safer thermal management systems. ‘Standard’ accelerated rate calorimetry setup provides means to measure the addition of energy exhibited through the body of a Li-ion cell. This dissertation considers the total energy generated during thermal runaway as distributions between cell body and hot gases via inclusion of a unique secondary enclosure inside the calorimeter. This closed system not only contains the cell body and gaseous species, but also captures energy release associated with rapid heat transfer to the system unobserved by measurements taken on the cell body. An inverse relationship between state-of-charge and onset temperature is observed. Energy contained in the cell body and gaseous species are successfully characterized. Significant additional energy is measured with the heating of the secondary enclosure. Improved calorimeter apparatus including a secondary enclosure provides essential capability to measuring total energy release distributions during thermal runaway.