Battery technology in EVs When discharged, a battery produces electrical energy by converting chemical energy, and when charged, it converts electrical energy back into chemical energy. Batteries are composed of electrochemical cells placed in a parallel–series configuration.
Domestic research on power batteries is mainly experimental, focusing on engineering applications, and in recent years, with the need for research on battery thermal management systems, it has gradually shifted to theoretical modeling and simulation analysis.
Vibration and shock tests must be performed on batteries to guarantee their reliability and protection. Currently, three international test standards, namely, UN 38.3, ISO 12405-1, and SA J2380, are frequently used for battery vibration and shock testing. The test standards for battery security and safety are listed in table 3 .
Li-ion-based batteries are utilized as the main energy source in BEVs, such as the Nissan Leaf, and Ni-MH batteries are frequently employed as backup energy sources in HEVs, such as the Toyota Prius. As a crucial module of EV, the battery has undergone a lengthy development process to fulfill the requirements of EV manufacturers.
A dedicated BMS is required to diagnose and predict these failures so that the battery can operate safely and efficiently [213, 214]. The cell capacity diminishes as cell breakdown progresses, whereas the internal cell endurance increases rapidly. This results in poor battery cell performance, rendering them unsuitable for use in EVs.
In order to ensure the safety of electric vehicles in high and low temperature environments, improve the performance of electric vehicles and the service life of power battery packs, power battery thermal management technology has been widely emphasized by major automobile companies.