lications involving cell safety through battery system safety. The focus is on refining large-format lithium-ion battery standards (UL 2580 for electric vehicles, UL 2271 for light electric vehicles and UL 1973 for light electric rail and stationary applications — for more information, please refer to the third article in this journal, “Advancing Lithium-ion Battery Standards”), revising cell requirements to address specific applications, verifying cell operating regions, ensuring that battery systems maintain safe cell operating regions, and exploring system failure mode effects analysis (FMEA) and functional safety.10
Research at UL, along with collaborations with well-known battery safety research laboratories, has resulted in the development of the Indentation Induced ISC test. This testing approach shows promise as a candidate for battery safety standards, most likely as a screening test. To date, analysis of results from cells subjected to the Indentation Induced ISC test shows a correlation between test performance (observed severity of failure) and a variety of cell parameters, including energy density, thermal stability of active materials and cell chemistry.11
With recalls and other safety issues related to lithium-ion batteries still making headlines, there is a heightened need for the kind of open and cooperative dialogue UL and other key stakeholders are engaging in to share information on the failure modes of lithium-ion cells and to help develop and refine ISC tests for consensus-based safety standards.12 We are committed to evolving standards to help drive the safe use of lithium-ion batteries as their applications expand to more and more industries and products. As the leading organization for lithium-ion battery safety testing, UL is focused on the full range of battery chemistries and designs, including different materials, component-level characterization at the cell level and highly integrated battery systems. We will continue to dedicate significant resources to battery safety research and will continue to actively improve existing standards and develop new ones.