In 2013-14, the newly launched Boeing 787 experienced a series of incidents highlighting problems with lithium-ion batteries used in the new aircraft’s systems. These began with a fire that started in a battery that overheated in an empty 787 operated by Japan Airlines at Boston’s Logan Airport in January 2013. Then a few days later, a battery malfunction on board an All Nippon Airways 787 forced the aircraft to make an emergency landing. These incidents eventually led to the temporary global grounding of the entire 787 fleet.
With safety and reliability major concerns when it comes to lithium-ion battery use, multi-physics simulation company Comsol has been developing mathematical modeling tools to help engineers improve battery design. “The understanding and optimization of fundamental components of the battery such as electrodes, electrolyte and separator can be accelerated using modeling and simulations,” says Ed Fontes, chief technology officer at Comsol. The systems for thermal management, current collection and state-of-health monitoring of lithium-ion batteries also can be developed with high-fidelity, multi-physics simulations, potentially improving performance and enhancing safety characteristics.
Battery life is a major consideration, to which safety and reliability are closely related. Discharge, wear and failure should occur slowly, and in a controlled and transparent way. “This is not only an issue of the chemistry of the battery but also of the design, since uneven current density distribution and poor control of discharge/recharge and of the thermal management system may accelerate wear and increase the risks of failure,” Fontes says.
“Short circuits formed by metal deposition may be responsible for decrease in performance as well as an increased risk for runaway heating,” he notes. “Technologies for state-of-health monitoring are required in order to continuously assess the state of the battery system and the risks of failure.”