A Sensitive Capacitive Pressure Sensor with Micro-Dome Iontronic Structure for Lithium-Ion Batteries

The safety performance of lithium-ion batteries is a key factor affecting the development of electric vehicles, among which safety hazards caused by mechanical stress have attracted much attention. Monitoring the contact pressure between lithium-ion batteries can provide more information about the state of health, while existing sensing devices have low integration and poor real-time performance. In this study, a capacitive pressure sensor with a micro-dome structure ionic gel dielectric layer is designed. Through multi-physics simulation analysis, the stress distribution characteristics and pressure response mechanism of the sensor are systematically revealed. The sensor exhibits a stepped sensitivity characteristic within a three-level pressure range, and has the advantages of high sensitivity, fast response (98 ms), and excellent durability (over 4000 compression cycles). It can be integrated into the gaps between battery cells without affecting module assembly and normal operation. Experimental verification shows that the sensor can effectively monitor the pressure changes of lithium-ion batteries under mechanical shock at different speeds and charge–discharge cycles at different rates. This study provides an innovative solution for lithium-ion battery safety monitoring.