Size-dependent Failure Behavior of Lithium-Iron Phosphate Battery under Mechanical Abuse

The use of battery electric vehicles is one of the green solutions to reduce environmental pollution and save the Earth. Based on the power, speed, and space constraints, the battery geometries (size and shape) are decided in the battery electric vehicles. However, battery failure assessment and abuse testing are much needed to ensure its safe operation. Herein, four types of lithium-iron phosphate batteries viz. 18650, 22650, 26650, and 32650 are considered to conduct lateral, longitudinal compression, and nail penetration tests. The mechanical failure is characterized by the voltage drop and temperature rise at the onset of the first short-circuit is identified by Aurdino-based voltage sensor module and temperature measurement module. The battery failure load and peak temperature at the onset of internal short-circuit during different mechanical abuse conditions are found to rely on the battery size strongly. The failure due to the onset of internal short circuit is observed to be delayed for small-sized 18650 batteries during lateral compression, unlike longitudinal compression and nail penetration test. At the onset of the short circuit, the LFPBs showed variation in temperature above the ambient value of 28 degree C. Among the LFPBs considered, the lowest variation of temperature rise (considering ambient temperature) is found to be 5.25 degree C for type 26650. The outcome of this work is anticipated to demonstrate the significance of the choice of battery sizes for different desired applications safely.Comment: 15 pages, 6 Figures, 2 tabl