The temperature of electric vehicle batteries needs to be controlled through a thermal management system to ensure working performance, service life, and safety. In this paper, TAFEL-LAE895 100Ah ternary Li-ion batteries were used, and discharging experiments at different rates were conducted to study the surface temperature increasing characteristics of the battery. To dissipate heat, heat pipes with high thermal conductivity were used to accelerate dissipating heat on the surface of the battery. We found that the heat pipe was sufficient to keep the battery temperature within the desired range with a midlevel discharge rate. For further improvement, an additional thermoelectric cooler was needed for a high discharge rate. Simulations were completed with a battery management system based on a heat pipe and with a combined heat pipe and thermoelectric cooler, and the results were in line with the experimental results. The findings show that the combined system can effectively reduce the surface temperature of a battery within the full range of discharge rates expected in the battery used.

Latent heat thermal energy storage systems play a crucial role in aligning energy supply with demand, enhancing the efficiency of energy usage, thereby aiding in energy conservation and emissions reduction, and promoting the efficient use of renewable energy. Therefore, we constructed an experimental apparatus for a shell-and-tube latent heat storage. This apparatus was utilized to investigate how varying the inclination angle of the heat storage device, the inlet temperature of the heat transfer fluid (HTF), and water flow direction affect both the heat transfer behavior and the thermal efficiency of the system. The findings indicate that as the inlet temperature rises, the melting rate of the phase-change material (PCM) increases; when the inclination angle is 0°, for every 5 °C increase in water temperature, the time required to reach thermal equilibrium is shortened by 2 h, and the time needed for the PCM to transition from a solid to a liquid state is correspondingly reduced by 2 h. Additionally, the temperature variation trend of the phase-change material remains fundamentally consistent at different inclination angles. However, as the angle increases from 0° to 90°, there is a gradual reduction in the melting rate. Whether the water enters from the top or bottom, the melting rate of the PCM remains almost unchanged, and the stabilized temperature of the PCM is also nearly the same.

Thermal management of lithium-ion batteries is crucial for enhancing the performance and safety of electric vehicles. This study proposes a novel liquid cooling plate featuring gradually varied circular notched fins (GV-CNF) to improve the thermal management of a commercial LiFePO₄ battery. The results indicate that GV-CNF provides a more uniform temperature distribution, a lower T_a, and a reduced ∆P compared to circular fins under identical conditions, leading to a 41.1% improvement in the comprehensive performance evaluation indicator (TP). Notably, the value of TP increases with the height of the coolant channel; however, when the channel height exceeds 4 mm, the change in TP value becomes minimal. Afterward, further studies were conducted to investigate the effects of different inlet–outlet configurations on the cooling performance. The single-inlet, dual-outlet configuration (Type III) for the liquid cooling plate not only reduces the T_a value but also exhibits the lowest ∆P and a smaller high-temperature region. Additionally, when the outlet spacing (L) is 81 mm, the lowest T_a recorded is 27.87 °C, and the ∆P is 3.13 Pa, indicating that this is the best outlet spacing. Additionally, comparative analysis of GV-CNF with serpentine-channel and circular-fin cooling structures reveals that the GV-CNF design effectively reduces the maximum temperature of the battery module, minimizes localized heat accumulation, and maintains low energy consumption, demonstrating superior overall thermal performance.

The spontaneous combustion of electric vehicles occurs frequently, and the main reason is the thermal runaway of a lithium-ion battery. In order to prevent the heat that is produced in the use of a lithium-ion battery out of control, this study proposed a coolant circulation cooling system, that is, the heat generated by the lithium-ion battery is transferred to heat sinks through aluminum plates and copper rods, and then dissipated through the coolant. Based on a CALB-LB5F73 LiFePO₄ battery pack, experiments with the coolant circulation cooling system were conducted to study the temperature rise characteristics at different ambient temperatures. The temperature of the battery pack was still close to the upper limit of permitted temperature when the ambient temperature reached 313 K. Further improvement, increasing the diameter of copper rod of the system was proposed to enhance heat dissipation and simulations with this scheme were completed. The findings show that the cooling system can clearly reduce the temperature of a lithium-ion battery pack and control the temperature within the safe temperature range.

Thermoelectric generators (TEG) is the device that can directly convert heat into electricity by the Seebeck effect, which is fascinated for waste heat recovery. An experiment was setup to study the influence of heat flux through the thermoelectric module on the power output and efficiency of a commercial Bi₂Te₃-based thermoelectric modules. The experimental result indicated that the power output evidently increased with the increasing heat flux through the thermoelectric module (TEM), while the conversion efficiency increased significantly at first then the tendency became mild with the increasing heat flux for a given air flow velocity and flow temperature. The temperature differences across the thermoelectric module are almost identical with various air velocity, while the power output and efficiency increased with the increase of cooling flow velocity with a fixed heat flux through the TEM. The power output and efficiency almost linearly decreased with the increase of cooling flow temperature with a fixed heat flux through the TEM and a fixed cooling flow velocity. The maximum output power can be obtained by maximization heat flux without exceeding the upper temperature limit of thermoelectric module.