New 'Passive' Battery Thermal Management System

Zero Electric Vehicles, Inc, announced what they describe as a revolutionary, low-cost, sustainable plant-based "passive" thermal management technology for BEV mobility applications.

"We are thrilled to announce this breakthrough. Dr. Kannan and his team have worked tirelessly to pioneer this new method to stabilize battery thermal management during faster charge/discharge cycling. This innovation is a shining example of the focus and commitment ZEV has to offer towards the next chapter in EV adoption," said Carolyn Maury, ZEV CEO.

Lithium-ion battery (LIB) systems with liquid electrolytes currently hold a large portion of the portable and automotive battery markets, with several advantages over other battery systems, such as higher operating voltage, higher energy and power densities, lower self-discharge rate, and longer cycle life. However, safety is still a major issue for LIBs in electric power equipment as liquid electrolytes contain combustible organic solvents, leading to a risk of catching on fire during faster charge and discharge operations, especially in larger modules. In particular, the battery module's temperature profile and pack play a crucial role in terms of performance and safety for automotive applications. A properly designed thermal management system is essential to prevent overheating and uneven heating across a large battery module, leading to degradation, mismatch in cell capacity and thermal runaway. Hence, battery thermal management is critical for improving thermal safety, prolonging the cycle life and overall lifespan of batteries with liquid electrolytes at a high charge and discharge rate.

Historically, air is used as a cooling medium by passing between the LIB cells for controlling the module temperature. Liquid has also been used for cooling of battery cells and can be circulated to a remote liquid-to-air heat exchanger for discharging excess rejected heat. However, this active cooling/thermal management of the LIB module consumes additional electrical energy. The revolutionary passive thermal management system with sustainable plant-based phase change material (PCM) eutectic mixture is demonstrated to ensure thermal uniformity with exceptional safety with higher charge/discharge rates. Initial research with cylindrical LIBs with groundbreaking results through passive thermal management using plant-based PCM in a battery module has been protected through U.S. patent application # 63/207,509.

"ZEV's immersive method to passive battery temperature control is a significant breakthrough in LIB thermal stability across operating temperatures and fast charge/discharge cycling, improving battery performance, cycle life and safety for ZEV customers,"

said Dr. A.M. Kannan, ZEV Chief Scientist and Lead Inventor on the announcement.