Conceptualization of a novel battery thermal management system based on capillary-driven evaporative cooling

In conventional heat pipe based battery thermal management systems the thermal contact between the battery and the heat pipe is enhanced by means of heat conductive elements. These additional elements introduce multiple layers of thermal resistance and contribute to increased weight. This paper aims to address this issue by minimizing the contact thermal resistance and potentially reduce this additional weight. The proposed solution relies on capillary-driven evaporative cooling (CDEC), wherein a wick structure is directly integrated onto the battery's surface to enable direct cooling. To demonstrate this concept, an experimental study was conducted by affixing a Copper foam to an emulated battery block, and using ethanol and Novec 7000 as cooling media. The CDEC system's thermal performance was assessed under three heating conditions, and different operating conditions. The results indicated that the copper foam with higher pore density outperformed the other due to its greater wetting height. The maximum cell surface temperature was maintained around 40 degrees C for a continuous 50 W heat input. Furthermore, the thermal resistance of the system was lowered by a factor of 6 compared to an air-cooled system. The thermal resistance ranged from a minimum of 0.32 to a maximum of 1.5 K/W, which were comparatively low compared to some existing battery thermal management system designs. This paper in-troduces an innovative battery cooling concept, presents experimental evidence of its feasibility, and demon-strates its ability to effectively regulate battery temperature within acceptable limits even under high heat loads, while minimizing overall thermal resistance.