Identifier: KD01RCM
Batteries are a part of our every day lives. They store energy in a chemical form and can be recharged and reused. With increasing emphasis on greener technologies such as hybrid and electric vehicles, more electric aircraft and renewable energy generation, battery technology becomes more important. In electric vehicles, the battery pack is crucial to the range of the vehicle. In the field of renewable energy generation this is used to store energy for off peak use while in modern aircraft the battery packs power up engines and aircraft systems, provide backup power for critical systems and power ground support to reduce airport emissions.
In each application, careful monitoring of the comfort temperature and voltages of the battery pack is crucial to life of the pack. Battery overheating is a main concern during repeated cycles of charging and discharging. Indeed, there have been a few cases in electric vehicles and aviation in which battery packs overheated to the extent of catching fire (Boeing 2013; Bullis, 2013), causing health and safety concerns.
Conventional battery pack cooling is inefficient. As the coolant passes over the battery stack, it gradually warms up, and its effectiveness to cool subsequent batteries deteriorates. This causes batteries in the same stack to be at different temperatures. As the battery chemistry is temperature sensitive, battery cells in the same pack but at different temperatures respond differently to charging and discharging cycles. Moreover, the battery cell at the highest temperature degrades at a faster rate thus dictating the life of the pack. To counter this problem, the industry has developed complex and expensive battery management systems that monitors the temperature of each cell and adjusts the individual charging rate. While this protects the cell, it limits the charging rate causing long waiting times in between battery use.
We tackle this challenge in two ways: by designing an evaporative cooling mechanism that keeps battery cells in the same stack at a uniform temperature and by redesigning the battery to include a cooling device within its structure. Both solutions promise a lower risk of battery overheating, a longer life, a simper battery management system and higher charging and discharging rates.