Advanced Battery Thermal Management Solution for Electric Vehicles

Electric vehicles (EVs) are experiencing explosive developments due to their advantages in energy conservation and environmental protection. As a pivotal component of EVs, the safety performance of lithium-ion batteries directly affects driving miles and even safety; hence, a battery thermal management system (BTMS) is especially important. To improve the thermal safety performance of power battery modules, first, a new leak-proof phase change material (PCM)-coupled liquid-cooled composite BTMS for large-scale battery modules is proposed in this research. Second, the numerical simulation analysis method was utilized to analyze the influences of the fluid flow channel shape, working fluid inlet temperature, inlet velocity, and reverse flow conditions on the BTMS. Eventually, the abovementioned performances were compared with the traditional PCM-coupled liquid-cooling strategy. The relative data indicated that the T_max was reduced by 17.5% and the ΔT_max was decreased by 19.5% compared to the liquid-cooling approach. Further, compared with conventionally designed PCM composite liquid cooling, the ΔT_max was reduced by 34.9%. The corresponding data showed that, when using the e-type flow channel, reverse flow II, the inlet flow velocity was 0.001–0.005 m/s, and the inlet temperature was the ambient temperature of the working condition. The thermal performance of the anti-leakage system with a thermal conduction slot PCM-coupled liquid-cooling composite BTMS reached optimal thermal performance. The outcome proved the superiority of the proposed BTMS regarding temperature control and temperature equalization capabilities. It also further reduced the demand for liquid-cooling components, avoided the problem of the easy leakage of the PCM, and decreased energy consumption. Full article

With an increase in global warming, battery electric vehicles (BEVs), which are environmentally friendly, have been rapidly commercialized to replace conventional vehicles with internal combustion engines. Unlike traditional internal combustion engine vehicles, the powertrain system of BEVs operates with high efficiency, resulting in lower heat generation. This poses a challenge for cabin heating under low-temperature conditions. Conversely, under high-temperature conditions, the operating temperature of a high-voltage battery (HVB) is lower than the ambient air temperature, which makes cooling through ambient air challenging. To overcome these challenges, in this study, we proposed an integrated thermal management system (ITMS) based on a heat pump system capable of stable thermal management under diverse climatic conditions. Furthermore, to assess the ability of the proposed ITMS to perform thermal management under various climatic conditions, we integrated a detailed powertrain system model incorporating BEV specifications and the proposed ITMS model based on the heat pump system. The ITMS model was evaluated under high-load-driving conditions, specifically the HWFET scenario, demonstrating its capability to perform stable thermal management not only under high-temperature conditions, such as at 36 °C, but also under low-temperature conditions, such as at −10 °C, through the designated thermal management modes. Full article

This study proposes a simulation technique for investigating a battery thermal management system based on direct refrigerant cooling (BTMS-DRC). The main focus is to investigate the temperature uniformity and working temperature of the module housing. The simulation technique employs a finite element method for a combined conduction–convection heat transfer to predict the module housing temperature. The refrigerant side is based on two-phase flow evaporation, which is represented by the convection heat transfer under a certain refrigerant saturation temperature. The real BTMS-DRC, which is based on the dual-evaporator vapor compression refrigeration system, is constructed for experimentation with the test bench. The simulated result is validated with the experimental results to ensure correction of the modelling. Error rates of approximately 2.9–7.2% are noted throughout the specified working conditions. The BTMS can produce temperatures of less than 35 °C under conditions where 80–320 W heat is generated. The difference in the temperature of the module is around 1.7–4.2 °C. This study also investigates the impact of heat generation, the convection heat transfer coefficient (h_ref), the refrigerant saturation temperature, and thermal conductivity on the module’s temperature. The thermal conductivity ranges from 25 to 430 W/m·K, while the h_ref ranges from 80 to 400 W/m²·K. Full article

The electric vehicle thermal management system (EVTMS) plays a crucial role in ensuring battery efficiency, driving range, and passenger comfort. However, EVTMSs still face unresolved challenges, such as accurate modeling, compensating for temperature variations, and achieving efficient control strategies. Addressing these issues is crucial for enhancing the performance, reliability, and energy efficiency of electric vehicles. Therefore, this study presents a cooling EVTMS model, considering both the battery pack temperature and the cabin comfort, and utilizes the prediction of neural network as a feedforward in a fuzzy PI controller to compensate for the model temperature variations. The simulation results reveal that, compared with PI controller and MPC, the neural network fuzzy PI (NN-Fuzzy PI) controller can well predict and compensate for the system’s nonlinear characteristics as well as the time-delay caused by heat transfer, achieving superior control performance and reducing energy consumption. The battery pack temperature and $\mathrm{PMV}$ fluctuations are effectively constrained within [−0.5, 0.5] and [−0.1, 0.1], reducing up to 150% and 164%, and the energy consumption of the pump and compressor are reduced by up to 0.23 and 100.1 $\mathrm{KJ}$, with ranges of 18% and 2.68%. Meanwhile, the neural network feedforward also works effectively in different controllers. The findings of this research can provide valuable insights for TMS engineers to select advanced control strategies. Full article

The thermal performance of a lithium-ion battery module comprising three cells contained within a casing was investigated at discharge rates of 3C and 5C with three different cooling strategies: forced air, phase-change material (PCM), and a hybrid system using a combination of forced air and the PCM. Three levels of fan speed (5000 rpm; 7000 rpm; and 9000 rpm) for cooling air flow were considered. A numerical simulation of heat transfer was performed using the ANSYS Fluent software. The electrochemical modelling of a battery was developed based on the NTGK approach, and the phase-change phenomenon was treated as an enthesis–porosity problem. The composite PCM, aluminum metal foam embedded in n-octadecane, had better heat dissipation performance than forced air convection. The PCM is significantly more effective at heat dissipation than forced air. Interestingly, when using a hybrid cooling system that combines forced air and a PCM, although it meets the operational requirements for Li-ion batteries in regard to maximum temperature and temperature uniformity at a 3C discharge rate, the airflow appears to have a negligible effect on thermal management and yields an indiscernible change in temperature. This can be attributed to a complex flow pattern that developed in a casing as a result of the suboptimal design of the inlet and outlet. Further studies will be required for the optimal positioning of the inlet and outlet, as well as the effectiveness of combining liquid cooling methods. Full article

The transportation sector is a significant contributor to greenhouse gas (GHG) emissions due to large energy consumption, which is why there is a need to promote the use of electric vehicles (EVs) to mitigate overall GHG emissions. To ensure market confidence towards EVs, battery packs’ energy storage capacity and thermal management system (TMS) must be optimized. Designing a battery pack that can withstand changes in temperature is essential to the TMS. In this study, we proposed two battery pack designs with cell arrangement angles of $\theta =\pi /3$ and $\theta =\pi$, respectively, to investigate TMS. The CAD models were drawn, and simulations were performed using ANSYS Fluent with a mesh size of 0.005m. The computational fluid dynamics (CFD) analysis was conducted to obtain the maximum and average temperature and fluid flow velocity. Our results show that the 3 parallel and 8 series (3p8s) battery pack design with a cell arrangement angle of $\theta =\pi /3$ is the most feasible and can consistently perform in thermal management. This design also has 15% less volume than the cell arrangement of $\theta =\pi$, allowing for more battery packs to be incorporated in the EV for a longer range of travel. Furthermore, this design can maintain the battery pack at its optimal operating temperature of 25 °C, reducing the incidence of battery runaway and ultimately lowering the EVs maintenance costs. The proposed design approach can serve as a basis for designing battery packs with optimized thermal management systems for EVs, contributing to the global effort to reduce GHG emissions. Full article

The development of hybrid technology can effectively solve the problems of the high pollution and energy consumption levels of automobiles. Therefore, an energy consumption prediction and control algorithm for hybrid vehicles based on a minimum equivalent fuel consumption model is proposed. The model’s battery power consumption is equivalent to the fuel consumption, and the sum of the engine fuel consumption and the battery equivalent fuel consumption is established as the objective function. By utilizing these factors, an innovative minimum equivalent fuel consumption model was constructed that could be used to measure the energy efficiency of hybrid vehicles. The longitudinal force result of braking force distribution control was obtained, as well as the energy consumption prediction structure of a hybrid electric vehicle. The rolling resistance, air resistance, and climbing resistance of the hybrid electric vehicles were calculated, and the energy consumption control algorithm for hybrid electric vehicles was constructed according to the calculation results. The experimental results indicated that under this research algorithm, the driving energy consumption of hybrid electric vehicles was relatively low and the energy consumption and energy efficiency measurements effectively met the actual demand, and the energy consumption prediction and control results were good. Full article

Electric vehicles (EVs) have become a viable solution to the emerging global climate crisis. Rechargeable battery packs are the basic unit of the energy storage system of these vehicles. The battery thermal management system (BTMS) is the primary control unit of the energy source of the vehicles. EV performance is governed by specific power, charging/discharging rate, specific energy, and cycle life of the battery packs. Nevertheless, these parameters are affected by temperature, making thermal management the most significant factor for the performance of a battery pack in an EV. Although the BTMS has acquired plenty of attention, research on the efficiency of the liquid cooling-based BTMS for actual drive cycles has been minimal. Liquid cooling, with appropriate configuration, can provide up to 3500 times more efficient cooling than air cooling. Direct/immersive and indirect liquid cooling are the main types of liquid cooling systems. Immersive/direct cooling utilizes the technique of direct contact between coolant and battery surface, which could provide larger heat transfer across the pack; however, parameters such as leakage, configuration, efficiency, etc., are needed to be considered. Indirect cooling techniques include cold plates, liquid jackets, discrete tubes, etc. It could result in complex configuration or thermal non-uniformity inside the pack. The paper intends to contribute to the alleviation of these gaps by studying various techniques, including different configurations, coolant flow, nanoparticles, varying discharging rates, different coolants, etc. This paper provides a comprehensive perspective of various techniques employed in liquid cooling battery packs, identifying the shortcomings in direct/immersive and indirect liquid cooling systems and discussing their mitigation strategies. Full article