Reducing temperature inhomogeneity in 280Ah lithium-ion battery and battery pack by single phase immersion cooling strategy

Abstract

The energy storage stations (EESs) exhibit a larger scale and more pronounced safety concerns than electric vehicles (EVs). Presently, EESs predominantly employ large-capacity lithium-ion batteries (Nominal capacity ≥280Ah) as the primary energy storage units, which possess a more distinct necessity of thermal management compared to their smaller batteries. To ensure the safety of EESs, this study conducted a series of analysis on the single-phase immersion cooling strategy, with a focus on key parameters such as coolants, flow direction, flow rate, and battery gap to evaluate their impact on temperature rise ($T$), module temperature difference ($\Delta T_{between-cells}$), and battery temperature difference ($\Delta T_{in-cells}$). The results demonstrated that the immersion battery thermal management strategy (IBTM) can effectively control $T$ and reduce temperature inhomogeneity in battery module, maintaining $T$ within 30 °C, keeping $\Delta T_{between-cells}$ within 0.5 °C and reducing $\Delta T_{in-cells}$ to 2.18 °C. Besides, flow directed along the thickness of the battery (Flow I) is more effective in reducing temperature inhomogeneity. Although Mineral Oil (MO) and AmpCool AC-100 (AC-100) exhibit relatively poor temperature control ability at low Reynolds numbers (Re), they demonstrate greater promising capabilities at higher Re values. This study is of great significance for promoting the optimization and safety design of large-capacity lithium-ion battery modules and improving the safety performance of EESs.