Process failure mode – product failure mechanism- effect analysis ((PFM)²EA): A novel risk assessment methodology for automated battery disassembly - Integrating process and product safety in repurposing

Abstract

The increasing adoption of electric vehicles has led to a surge in end-of-life traction batteries, necessitating safe and efficient repurposing strategies. This study introduces a novel risk assessment methodology, the process failure mode - product failure mechanism - effect analysis ((PFM)²EA), designed to evaluate safety risks in automated battery disassembly processes. The (PFM)²EA method combines two established risk analysis approaches: one focused on manufacturing processes (process failure mode and effects analysis - PFMEA) and another on product failure behaviors (failure modes, mechanisms, and effects analysis - FMMEA). By linking these perspectives, the method addresses the critical gap between process and product risks in separation processes for battery repurposing. Our approach employs a tripartite risk categorization framework, distinguishing between immediate safety hazards, long-term safety risks, and potential performance issues of reused components. The method introduces a fourth variable to the traditional scoring system, which considers severity, likelihood of occurrence, and detectability of a product failure, by adding a fourth factor: the likelihood of process failure. The determination of which was simplified by implementing an analytic hierarchy process. This enhancement allows for a more comprehensive assessment of potential hazards originating from product failure mechanisms triggered by process faults. To validate the (PFM)²EA method, a preemptive risk assessment of theoretical automated disassembly processes for three commercially available battery systems has been conducted. The study focused on processes aimed at extracting energy storage components for reuse and repurposing, examining how safety considerations influence process selection. The findings demonstrate the effectiveness of the (PFM)²EA method in identifying and prioritizing safety risks in battery disassembly processes. A Monte Carlo Simulation confirmed the robustness of the risk evaluations under input uncertainty, reinforcing the method’s reliability. This research contributes to the development of safer and more efficient battery repurposing strategies, addressing critical challenges in the circular economy of energy storage systems.