THERMAL MANAGEMENT TECHNOLOGIES OF LITHIUM-ION BATTERIES APPLIED FOR STATIONARY ENERGY STORAGE SYSTEMS : Investigation on the thermal behavior of Lithium-ion batteries

Sammanfattning: Batteries are promising sources of green and sustainable energy that have been widely used in various applications. Lithium-ion batteries (LIBs) have an important role in the energy storage sector due to its high specific energy and energy density relative to other rechargeable batteries. The main challenges for keeping the LIBs to work under safe conditions, and at high performance are strongly related to the battery thermal management. In this study, a critical literature review is first carried out to present the technology development status of the battery thermal management system (BTMS) based on air and liquid cooling for the application of battery energy storage systems (BESS). It was found that more attention has paid to the BTMS for electrical vehicle (EV) applications than for stationary BESS. Even though the active forced air cooling is the most commonly used method for stationary BESS, limited technical information is available. Liquid cooling has widely been used in EV applications with different system configurations and cooling patterns; nevertheless, the application for BESS is hard to find in literature.To ensure and analyze the performance of air and liquid cooling system, a battery and thermal model developed to be used for modeling of BTMS. The models are based on the car company BMW EV battery pack, which using Nickel Manganese Cobalt Oxide (NMC) prismatic lithium-ion cell. Both air and liquid cooling have been studied to evaluate the thermal performance of LIBs under the two cooling systems.According to the result, the air and liquid cooling are capable of maintaining BESS under safe operation conditions, but with considering some limits. The air-cooling is more suitable for low surrounding temperature or at low charging/discharge rate (C-rate), while liquid cooling enables BESS to operate at higher C-rates and higher surrounding temperatures. However, the requirement on the maximum temperature difference within a cell will limits the application of liquid cooling in some discharge cases at high C-rate. Finally, this work suggests that specific attention should be paid to the pack design. The design of the BMW pack is compact, which makes the air-cooling performance less efficient because of the air circulation inside the pack is low and liquid cooling is more suitable for this type of compact battery pack.