Emerging Thermal Safety Characteristics of Large-Capacity Lithium Iron Phosphate Lithium-Ion Batteries

Abstract

Lithium iron phosphate is generally considered to be one of the most thermally stable cathode materials for commercial lithium-ion batteries, while emerging thermal safety characteristics rise with the large-capacity lithium-ion batteries in large-scale stationary energy storage power stations. In this review, different safety risks of lithium iron phosphate batteries compared with lithium nickel manganese cobalt oxide batteries from the view of general features of thermal runaway and the content of extremely dangerous hydrogen are discussed, especially the emerging thermal safety characteristics for large-capacity lithium-ion batteries. First, the prevailing belief that lithium iron phosphate is safer than lithium nickel manganese cobalt oxide is discussed based on the general features of thermal runaway, including characteristic temperature, heat generation, mass loss, and combustion possibility. Second, the rising viewpoint that the hydrogen content in the thermal runaway of lithium iron phosphate batteries is higher than that of lithium nickel manganese cobalt oxide batteries is examined. More importantly, different thermal behaviors are strongly related to the battery capacity (ampere hour). Additionally, the solutions to reduce hydrogen generation in lithium-ion batteries are presented in the outlook. This review presents comprehensive insights into the thermal safety behaviors of the commercial lithium-ion batteries with lithium iron phosphate cathodes.