A CFD thermal analysis and validation of a Li-ion pouch cell under different temperatures conditions

Abstract

Li-ion cells are one of the core components for the actual and future electric mobility. Differently from other types of applications and due to the high charge/discharge rates, the thermal-related issues in batteries for mobility are drastically relevant and can affect the reliability, the safety and the performance of the system. Indeed, limited temperature differences within a battery pack have a significant impact on its efficiency, thus it is important to predict and control the cell and battery pack temperature distribution. In the proposed study, a CFD analysis has been carried out to quantify the temperature and heat distribution on a single li-ion pouch cell. The main objective of this work is to determine the temperature imbalance on the cell and the required cooling load in order to be able to correctly design the cooling system and the best module architecture. The internal heat generation occurs as a result of electrochemical reactions taking place during charge and discharge of batteries. An electric model of the cell allows to assess the thermal power generation; the model parameters are changed according to the operative conditions to improve the accuracy, specifically to take into account varying temperature conditions and C-rates. The high accuracy of the model with respect to experimental data shows the potentiality of the proposed approach to support the optimization of Li-ion modules cooling systems and architecture design.

Improved Thermal Management of Li-Ion Batteries with Phase-Change Materials and Metal Fins

“…Four different cooling methods were studied, including natural convection air, finning, pure PCM, and PCM and finning. The model was validated using experimental tests conducted by Perez Estevez et al [44]. The purpose of the presented model is to highlight the results obtained during the discharge phase at 1C and 2C.…”

“…In the equation, UDS0 is the positive side diffusivity (m 2 /s), σ is the electric conductivity (S•m −1 ), δ is the thickness, and subscripts c and e denote the collector and electrode (m), respectively. An analogue equation was used to estimate UDS1, the negative side diffusivity [44].…”

“…Figure 5 identifies the measurement points located on the surface of the cell. The validation process consists of a comparison between the data obtained experimentally, contained in the study by Perez Estevez et al [44], and those obtained from the numerical model through the CFD simulation. A pouch cell with a graphite anode and a NMC cathode was used for the experimental activity.…”

“…Maximum heat production is generated at around 0% of the SOC. The temperature difference may be related to the determination of the set boundary conditions; in particular, the natural convection condition and its coefficient are an approximation of the reality of the problem [44]. The final MSE value for the battery voltage curve is 0.0413, a value strongly biased towards 0.…”