The battery technology for electric vehicles is constantly improving the capability of its charging and lifep, enabling a longer-lasting battery to be applied to a potential electric car avoiding the replacement problem (Bernardes, Espinosa & Tenorio, 2004). Various types of batteries has been employed through the history of electric vehicles, varying from lead-acid as in the first electric automobile to the Lithium-ion (Li-ion) cell technology in the modern era improving in range and efficiency, remaining environmentally friendly.
According to Tesla Motors, “The battery pack in the Tesla Roadster is the result of innovative systems engineering and 20 years of advances in Lithium-ion cell technology”. The Li-ion cell provides power efficiency, reliability for the electric vehicles. However, there are two types of Li-ion batteries one uses a liquid or gel for the electrolyte, and the other type uses a solid polymer making a dual role as separator and electrolyte. (Fuhs, 2009)
The high-powered Tesla vehicles are supplemented by a series of Li-ion batteries shown in fig: 1.7, in addition the set of batteries are enclosed in a single steel casing designed to withstand considerable condition in the vehicle. As one of the main benefit of the structure pack, it works similar as the radiator system of ICE. It serves to maintain the appropriate temperature level of each cell through a liquid coolant which enables effective heat transfer within the system. Whenever the battery temperature rises above a set threshold, the system releases a liquid coolant in the pack to stabilise the temperature in extreme condition (Tesla Motors, 2010).