Abstract
The paper presents the results of a collaborative research programme concerned with most aspects of thermal management of a compact electric vehicle fitted with a Sodium Nickel Chloride (ZEBRA®) traction battery. The battery operates with an electrolyte temperature typically around 320C, and an integrated approach to battery, powertrain and cabin climate thermal management is described. Experimental studies of cabin heating, air conditioning and powertrain cooling have been conducted at sub-system and whole-vehicle levels in order to objectively evaluate and validate various concepts. The experimental work is complemented by appropriate simulation activities, which include effects of the battery pack and power electronics thermal characteristics, along with the heat transfer properties of the passenger compartment and various heat exchangers. A primary objective of the work has been to integrate the vehicle thermal management sub-systems in order to recover waste energy wherever possible, and to effectively tackle the impact of a range of external climatic conditions. This leads to the minimisation of parasitic loads on the traction battery, and hence optimum range capability, whilst maintaining the desired levels of cabin climate and powertrain cooling performance. Results of the simulation and sub-system test work are presented along with whole-vehicle test data, demonstrating the benefits of the integrated approach in terms of powertrain thermal management, occupant comfort and vehicle range performance.
Keywords: Thermal, Battery, Heating, Cooling, Air Conditioning