FMEA used for the identification of critical loads applied to second-life mobile and stationary applications

The use of Lithium-ion batteries in second-life applications is becoming increasingly widespread. A battery extracted from an electric vehicle can be used in a wide range of applications, both stationary (e.g. energy storage system connected to a renewable energy source) and mobile (e.g. warehouse´s industrial vehicle). In order to ensure a successful transition from first to second-life, it is important to guarantee high safety standards considering the different potentially critical loads applied.

This research aims to study the risks associated with pouch Lithium-ion batteries during use in applications with different degrees of mobility, i.e. mobile and stationary, considering the different types of loads, i.e. electrical, thermal and mechanical, that can be applied.

Critical loads were obtained by studying the scientific literature. The loads considered in the investigation are overcharge, overdischarge, high C-rate, high temperature, low temperature, mechanical shock, indentation, and vibrations. After identifying the potentially critical loads, the associated risks were studied. Finally, Failure Modes and Effects Analysis (FMEA) was used as a methodology to assess the magnitude of the risks and determine which loads are most critical. The FMEA was applied considering two different scenarios: stationary and mobile applications.

The results show that the highest risks for both mobile and stationary applications are associated with high C-rates and in the case of mobile applications to mechanical loads (e.g. mechanical shock), which are negligible in the case of stationary applications.

The findings of this investigation can be used by comparing the critical loads with the specific load case of the mobile or stationary second-life application to be implemented. The comparison can be used to validate or invalidate the use of second-life batteries for the considered specific application and ensure a safe second-life implementation.

Research and results are part of the SafeLIB project. SafeLIB is an interdisciplinary project focusing on the safety aspects of automotive batteries.