Internal flow cooling of cylindrical lithium-ion batteries

• An internal liquid cooling method for cylindrical lithium-ion batteries is proposed. • Different coolants at varying C-rates and flow rates are studied. • Internal cooling ensures safe and uniform temperature distribution across the battery. • The pressure drop and power consumption of the system are analyzed. • The developed internal cooling supports efficient end-of-life battery recycling strategies. Fast charging of high energy–density batteries is becoming increasingly popular for energy storage systems, including in commercial and off-road electric vehicles. At higher charging rates, the battery temperature and heat dissipation rate increase, leading to a loss in battery performance, efficiency, and eventual life span. In this study, we demonstrate internal flow cooling of lithium-ion cylindrical batteries to help mitigate these challenges. We demonstrate that internal flows can be combined with conventional external flows to achieve dual flow cooling of cylindrical cells. We show enhanced cooling for regular charging rates (1C) as well as fast charging rates (4C) using internal coolant flow in 25 °C ambient conditions. We benchmark the battery performance using state-of-the-art external active cooling methods. Internal flow cooling was studied using a range of potential coolants, including deionized (DI) water, Novec 7300, and a 1:1 mixture of ethylene glycol and DI water (WEG). During charge and discharge cycles at 4C, the maximum core temperature of an as-purchased 18,650 lithium-ion battery reached up to 55 °C in ambient conditions. By implementing our internal cooling method, we limited the maximum battery core temperature below 30 °C, which resides within the optimal working temperature range of the battery. The cooling method developed here not only helps to alleviate thermal management challenges limiting the adoption of fast charge and discharge, but it also provides opportunities to rethink battery design and cooling architecture of battery packs for a variety of energy and transportation applications.