Validation Methods for Thermal Runaway Validation of Aviation Batteries

Aviation rechargeable lithium-ion battery safety is governed by RTCA DO-311A, which provides the minimum operational performance standards required to obtain FAA certification. This document was developed to support the certification of batteries for traditional applications like engine, APU start, or bus hold-up. As such, this means of demonstrating compliance is prescriptive in the way safety is assured, particularly in the case of thermal runaway containment. In support of an FAA research effort, cell and module level design considerations and worst-case scenarios for thermal runaway testing were evaluated as means to support development processes to assure passenger safety by battery containment in an aircraft. Cell level conditions will be discussed to provide practical methods for causing the early exothermic reactions resulting in the thermal runaway at the cell level. This information serves to not only to guide mechanical design and materials selection, but also to guide the test methodology for triggering thermal runaway in the module. Module level testing will be discussed to characterize the propensity towards thermal runaway cell-to-cell propagation dependent on module design implementation. The results from cell and module level testing can be integrated into a practical, worst case, and system level test design to demonstrate thermal runaway safety. Comprehensive frameworks for evaluating cell, module, and system level protections will inform the development of new means of compliance used for the certification and validation of electrified battery systems in this emerging field of electrified aviation propulsion.