(Invited) Impact of Aging on the Safety of Lithium-Ion Batteries and Implications for Diagnostics

The increasing voltage and energy density of lithium-ion (Li-ion) batteries have led to their widespread adoption in applications including consumer electronics, electric vehicles, and grid-tied energy storage systems (ESS). However, as energy density and installation sizes grow, so do concerns regarding safety, particularly the risks of thermal runaway and catastrophic fires. To better understand the risks and consequences associated with Li-ion battery failures, numerous studies have investigated their responses to various abuse scenarios. Additionally, established standards and certifications impose stringent requirements for battery safety testing. These tests are normally conducted with fresh batteries; however, given the expected lifetime of Li-ion batteries, it is critical to understand the safety profile of aged cells. This presentation explores the different degradation pathways of Li-ion cells cycled for more than seven years. We will also examine critical changes in the thermal, electrical, and mechanical abuse responses of these aged Li-ion cells compared to uncycled ones. By understanding how the safety profiles of aged cells differ from those of new cells, we can identify what diagnostics to prioritize and enable the design of more effective battery failure mitigation systems. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. SAND2024-17030A.