The thermal monitoring and management of lithium-ion batteries

Alcock, Keith Michael

Abstract

Battery Thermal Management Systems (BTMSs) are critical for the safe operation of Lithium-Ion Batteries (LIBs), especially in high-use applications such as electric vehicles (EVs). BTMSs are generally in charge of two major functions: monitoring battery temperature and managing temperature gradients caused by battery pack activity. The measuring of a LIB's temperature is essential for the successful deployment of battery packs. Furthermore, because degradation mechanisms are closely connected to battery temperature, the temperature gradient caused by battery discharge must be minimised as much as possible.

This thesis presents an experimental investigation of two battery thermal management fields: (i) testing of a novel temperature measurement method for individual cell-level monitoring of the LIB using Fibre Optic Sensors (FOS) and (ii) copper plated foam composite materials for passive LIB thermal management.

The first section of this thesis concentrates on the implementation of a FOS system on a single-cell and a three-cell parallel battery pack utilising Fibre Bragg Gratings (FBGs). In laboratory experiments, temperature measurements of a single-cell LIB and three-cell parallel battery pack are obtained by adopting a novel mounting method for the FOS, which is confirmed by comparison to standard thermocouple and platinum resistance sensing approaches. Cell-level temperature monitoring is achieved with an average error of 0.97 °C, 1.33 °C, and 1.27 °C for cells three different cells respectively, which is comparable with conventional thermocouple and platinum resistance sensing approaches.

The second section of this thesis demonstrates, experimentally, a novel use for copper plating of polyurethane foam substrates for passive battery thermal management. To capture heat generated by the cell, Phase Change Material (PCM) foam composites are used. A variety of experiments are carried out on various copper deposition quantities. The plated copper foam resulted in an average cell surface temperature reduction of 63.23%, which is comparable to the commercial alternative of 65.44% in the best scenario. This is crucial since the weight of the foam skeletons differs substantially in this scenario, with 91.47% less mass. It is demonstrated that copper plating can mimic the characteristics of solid commercially available foams, leading to a substantial reduction of copper material, lowering the total cost implication.

• Thesis Type: Thesis
• Deposit Date: Dec 8, 2023
• Publicly Available Date: Dec 8, 2023
• DOI: https://doi.org/10.17869/enu.2023.3406767
• Public URL: http://researchrepository.napier.ac.uk/Output/3406767
• Award Date: Oct 24, 2023