Forced Convective Immersion Cooling of Batteries With a Novel Phase-Change Slurry in High-Temperature Environments

Abstract

Thermal management of lithium-ion batteries in high-temperature environments is challenging because the available temperature range for safe operation is significantly limited. Therefore, this study proposes a novel immersion cooling of cylindrical 18650 Li-ion batteries using a phase-change material (PCM)-based slurry. The phase-change slurry, consisting of Organic Mixture-42 dispersed in silicone oil, is used as the coolant for the battery module, and its thermal and hydraulic performance is compared with that of a single-phase coolant. The proposed battery thermal management system design is numerically modeled using the multiscale multidomain framework with the Newman–Tiedemann–Gu–Kim model adopting a single-phase approximation for the slurry flow. The numerical model is validated against in-house experimental results by comparing average cell temperature profiles under similar operating conditions. A detailed parametric analysis is performed by varying slurry mass concentrations (0.5%, 1%, 2%, and 4%), flow rates (0.5, 1.0, 1.5, and 2.0 g/s), and ambient temperatures (35°C, 38°C, and 41°C) to assess their impact on thermal performance. The results indicate that the performance gain is maximum at a PCM concentration of 4% and a flow rate of 0.5 g/s, beyond which the benefits are offset by significantly increased pumping power. Incorporating PCM into the single-phase coolant significantly enhances the heat-carrying capacity, with a reduction in peak battery temperature rise by 11.8% for 4% PCM-slurry compared with silicone oil cooling, demonstrating the efficacy of the PCM, especially in high-temperature environments, where stabilizing battery temperature within a safe operating limit for a longer duration is essential.