Study on battery thermal management of autonomous underwater vehicle by bionic wave channels with liquid cooling

As lithium-ion batteries (LIBs) are used in autonomous underwater vehicles (AUVs) power systems, their thermal safety and reliability have seriously inhibited the development of AUVs toward high speed and long voyage. However, the related research on AUVs' battery thermal management is very limited. In this article, a novel and efficient liquid cooling scheme is proposed, for battery thermal management of AUV, which adopts bionic wave cooling channels. A three-dimensional heat dissipation model of the battery was developed, which considered the influence of battery internal resistance and state of charge on battery heat generation. The effects of discharge rate, channel shape, coolant mass flow rate, coolant inlet direction, and dynamic operation strategy on the battery maximum temperature and temperature variation were investigated during discharging process. It was found that the battery with bionic wave channels was superior to the battery with straight channels, regarding cooling efficiency. The maximum temperature and temperature difference of the former decreased by 12.8 and 5.3 K compared with the latter at 5C current discharging rate. Based on the bionic wave channels, increasing the mass flow rate of coolant was the most efficient route to reducing the maximum temperature and improving the uniformity of the battery temperature. A mass flow rate equal to 2.5 × 10−4 kg s−1 is reasonably recommended by considering the cooling efficiency comprehensively. The direction of the coolant inlet had little effect on the maximum temperature of the battery, but it significantly improved the uniformity of the battery temperature. Under the premise of meeting the cruising requirements of AUVs, alternating low-rate and high-rate discharge was more conducive to improving the temperature behavior of the battery. The conclusions of this article can provide reference for the battery thermal management system of AUVs.