Design and Simulation of Micro-Electro-Mechanical Systems (MEMS) Capacitive Pressure Sensor for Thermal Runaway Detection in the Electric Vehicle

Abstract

Recent advancement of vehicle technologies has resulted in development of replacing conventional Internal combustion engine (ICE) to Electric Vehicle (EV) mostly powered by Lithium-ion batteries (LIB). These batteries contain massive amount of energy confined in a very small space. Thermal runaway occurs when the batteries and its circuits start to heat up anomaly. Thermal runaway can cause failures that can lead to battery ignition, resulting in explosions and imminent threats to life and property. This research focused on MEMS capacitance pressure sensor, using three distinct square slotted diaphragm designs: clamped-square, four-slotted-square, and eight-slotted-square diaphragms. The investigation commenced with an evaluation of diaphragm performance, and subsequently, the diaphragm was integrated into the structure of the MEMS capacitive pressure sensor and subjected to simulation. Varied pressure levels ranging from 0.1 to 0.35 MPa were applied to both the diaphragm and the pressure sensor. The outcomes revealed that the eight-slotted-square diaphragm yielded the most substantial displacement, registering at 5.507 µm. It also exhibited the highest Mises stress of 644.67 MPa, and recorded the highest mechanical sensitivity at 15.7545 (10^-12/Pa). The clamped-square design, despite its slotted area, yielded the highest capacitance value among the three designs for the pressure sensor.