Development of a hybrid battery thermal management system for electric vehicle based on merged digital and physical twinning

Sun, Zeyu (2024). Development of a hybrid battery thermal management system for electric vehicle based on merged digital and physical twinning. University of Birmingham. Ph.D.

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Abstract

Vehicle electrification is emerging as a prevailing trend in the automotive industry. Lithium-ion batteries (LiBs) are the energy storage devices for electric vehicles, and their performance, lifespan, and thermal stability are notably impacted by the ambient temperature and its gradient. Advanced battery thermal management systems (BTMS) not only maintain optimal battery operating temperatures in low-temperature environments but also promote rapid heat dissipation from the power battery to mitigate risks such as heat accumulation and thermal runaway, thereby ensuring the safety and reliability of electric vehicles. The purpose of PhD research is to design a BTMS considering battery safety in electrified vehicles. The digital-physical twinning methodology has been incorporated into this study, encompassing the development of numerical models and physical prototypes, thereby enhancing the efficiency and effectiveness of BTMS development processes. The research provided three main contributions:
1) An algorithm-driven optimization method for LiB thermal modelling is proposed. The experimental results at various loads and different ambient temperatures are used for calibration and validation of the thermal model. The irreversible heat item of the LiBs model introduced a set of correction factors as a function of the state of charge (SOC). By optimizing the correction factors, the surface temperature error between experimental data and the simulation results was reduced to less than 0.5 °C.
2) A passive thermal management solution using copper foam-PCM is studied experimentally to enhance the heat dissipation performance of the battery module. A prototype of the battery module composed of 16 thermal dummy cells was constructed and used to conduct a reliability analysis for thermal management strategies. The results revealed that the addition of copper foam can effectively improve the heat dissipation performance of PCM, and can reduce the maximum temperature and improve the temperature uniformity of the battery module.
3) A hybrid BTMS integrating active liquid cooling and passive cooling is developed to improve the heat dissipation performance of the battery module in normal and thermal runaway conditions. Based on the established CFD model, a parameterisation study was conducted on the effect of both the selection of filling materials and the coolant flow rate on the thermal state of the battery module. In the multi-physical coupled process, the governing equations of the model involved the energy conservation equation, mass conservation equation, and momentum conservation equation. The results revealed that the proposed hybrid BTMS can effectively prevent thermal runaway propagation in the battery module.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):