Crashworthiness Models for Automotive Batteries

Safety is a key element of any device designed to store energy, particularly of electrochemical batteries, which convert energy of chemical reactions to electrical energy. Safety considerations are especially important when applied to large automotive batteries designed for propulsion of electric vehicles (EV). The high amount of energy stored in EV battery packs translates to higher probability of fire in case of severe deformation of battery compartment due to automotive crash or impact caused by road debris. While such demand for safety has resulted in heavier protection of battery enclosure, the mechanisms leading to internal short circuit due to deformation of the battery are not well understood even on the level of a single electrochemical cell. Moreover, not all internal shorts result in thermal runaway, and thus a criterion for catastrophic failure needs to be developed.This report summarizes the effort to pinpoint the critical deformation necessary to trigger a short via experimental study on large format automotive Li-ion cells subjected to large deformations as those occurring in deformation of battery module or pack. Mechanical properties of cell components were determined via experimental testing and served as input for constitutive models of finite element (FE) analysis. It has been rationalized that long-range stress fields occurring in spherical indentation of battery modules would trigger different deformation and failure scenarios compared to indentation of a single cell supported by a rigid flat surface. In order to investigate large deformations characteristic of battery module, a custom experimental set up has been built where the pouch cell was deformed against a compliant backing, which was represented by a ballistic clay. Experiments were also conducted on deformation of stacks of 10 pouch cells - configurations representing the half-modules in a Ford Focus EV battery pack without cooling plates and structural components. Comparison of the results shows promise for the compliant backing setup for safety evaluation of battery cells under more realistic conditions compared to indentation of single cell against undeformable backing where compression and electrode particle penetration through separator could be the major mechanism for short circuit.

  • Record URL:
  • Supplemental Notes:
    • Department of Energy Project 2088-A031-15.
  • Corporate Authors:

    Oak Ridge National Laboratory

    Oak Ridge, Tennessee  United States  37831

    National Highway Traffic Safety Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Department of Energy

    1000 Independence Avenue, SW
    Washington, DC  United States  20585
  • Authors:
    • Turner, John A
    • Kalnaus, Sergiy
    • Wang, Hsin
    • Simunovic, Srecko
    • Kumar, Abhishek
    • Gorti, Sarma
    • Allu, Srikanth
  • Publication Date: 2019-5


  • English

Media Info

  • Media Type: Web
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 47p

Subject/Index Terms

Filing Info

  • Accession Number: 01711154
  • Record Type: Publication
  • Report/Paper Numbers: DOT HS 812736
  • Contract Numbers: DE-AC05-00OR22725
  • Created Date: Jul 15 2019 1:14PM