Development of a distributed optical thermometry technique for battery cells

Abstract

A distributed thermometry technique using optical frequency domain reflectometry (OFDR) is developed and proposed as a temperature distribution sensor for energy storage systems such as battery packs in electric vehicles. A thin optical fiber serves as the sensor and measurements can be made at all points along the length of the fiber, making it ideal for determining temperature distributions of battery cells and modules with varying form factor. Additional enhancements are implemented to the OFDR sensor to increase its performance as well as ease its implementation. Experimental verification shows 1 cm spatial resolution can be achieved with an uncertainty of +/- 0 . 7 ? using a common SMF-28e optical fiber. The sensor is then demonstrated on a stack of three lithium-ion battery cells to measure its temperature distribution during a 1C discharge cycle.