Incorporating FFTA based safety assessment of lithium-ion battery energy storage systems in multi-objective optimization for integrated energy systems

Lithium-ion Battery Energy Storage Systems (BESS) have been widely adopted in energy systems due to their many advantages. However, the high energy density and thermal stability issues associated with lithium-ion batteries have led to a rise in BESS-related safety incidents, which often bring about severe casualties and property losses. To accurately evaluate the safety of lithium-ion BESS, this study proposes a probabilistic risk assessment method (PRA) that incorporates fuzzy fault tree analysis (FFTA) with expert knowledge aggregation. This approach takes into account the impact of BESS design variations and provides risk probability estimates for safety incidents in BESS. Based on the risk assessment, an energy system design framework is developed. This framework introduces a quantified risk indicator for BESS and establishes a mixed integer linear programming (MILP) model to examine the implications of BESS design on self-safety, as well as its interactive effects on the economics of integrated energy systems (IES). A case study conducted in an industrial park in Ningde, China, demonstrates that differences in safety requirements from investors can lead to cost variations of up to 6.8%. Furthermore, the study reveals the deep coupling between the safety and economics of BESS, highlighting that a cost-optimal approach which neglects safety can result in a 4.5% increase in the probability of BESS safety incident risk compared to a safety-optimal approach. Overall, this study contributes to the understanding of the interplay between safety and economics in BESS design. By employing a combination of quantitative evaluation and mathematical optimization methods, the present study provides a rational and feasible strategy, as well as a modeling perspective, for the safety design of BESS, paving the way for safer and more efficient integration of BESS in integrated energy systems.