Distributed Temperature Control for Safer Electric Vehicles

Abstract

As the adoption of electric vehicles continues to accelerate, managing the risks as- sociated with battery technology has become critical. To ensure the safety of people and goods, it is essential to secure battery packs throughout their whole lifecycle, during charging, discharging, logistic and storage phases. However, current battery packs, which must constantly evolve to meet demands for reduced weight, volume, and cost in a competitive market, often underestimate an essential parameter: temperature reading. Temperature monitoring is a key element of battery health, yet it is typically performed at only a few points on the pack, limiting the reliability of the diagnostic. The present study proposes a novel approach based on time-domain reflectometry (TDR) to achieve real-time, distributed temperature monitoring along a single cable sensor. While optical fibbers approaches are discussed in the literature, TDR methods present easier integration, cost-efficiency, robustness, and can be installed with existing battery cables. The possibility of using readily available components such as coaxial cables and time-domain reflectometers with advanced signal processing techniques enables accurate temperature measurement. The first results comprising calibration experiments for various coaxial cable and validated temperature measurements over a range of zero to five meters. Us- ing high-frequency signals, hot spots were detected with a precision of three centimeters, which is ideal for identifying overheating cells in a battery pack. Furthermore, the sys- tem can operate across a broad temperature range, including sub-zero environments and up to a hundred degrees, which is the range for battery surveillance. This innovative solution presents a promising path forward in Structural Health Monitoring, paving the way for safer and more reliable electric vehicle batteries.