Flexible III-N Thin-Film Piezoelectric Sensor for Smart Lithium-Ion Battery Management System

Abstract

Although the embedded sensors in lithium-ion batteries must be active in harsh thermal and chemical conditions during thermal runaway, the current battery management system still faces challenges. We develop thermally/chemically stable III-nitride piezoelectric sensors to detect physical deformation in Li-ion batteries. Analysis reveals the increased piezoelectric outputs of sensors (similar to 6-times), correlating with battery degradation (70% level of initial capacity). Electrochemical impedance analysis confirms that the increased thickness changes of the battery accompany a 2.5-times increase in charge-transfer resistance. We simulate the calculations between the volumetric displacement and piezoelectric voltage of the sensor and support the experimental results.