Optimisation of Cold Plate Design Technology for Blade Battery Management of New Energy Vehicles

Abstract

Blade batteries are widely used in new energy vehicles and the long strip structure helps improve the energy density of the system. Under high-rate operation and fast charging conditions, the heat accumulation on the surface and inside of the battery cell is easier to concentrate and the temperature gradient is enlarged, which affects the cycle life and increases the trigger probability of thermal runaway. To improve the heat dissipation capacity and temperature uniformity, three types of cold plate models with different flow channel structures, namely single straight channel, double serpentine channel and microchannel structure, are constructed in this study and the comparative analysis is carried out by combining experimental data with 3D thermal fluid-solid coupling simulation. The experimental samples were discharged at the inlet liquid temperature of 30 ℃ and the flow rate of 3.0-4.5 L/min and the data of multi-point temperature change on the surface of the battery cell were collected. The temperature error of the simulation model is controlled within 1.2 ℃ and the pressure drop error is controlled within 8 %, which verifies the reliability of the model. The results show that the microchannel structure has outstanding heat dissipation performance and the maximum temperature can be maintained at about 43 ℃, the maximum temperature difference (ΔT) can be controlled below 5 ℃ and the Temperature Uniformity Index (TUI) is raised to 0.89, which slows down the attenuation difference between cells and improves the thermal safety margin. The double serpentine channel balances the heat transfer capacity and flow resistance and its comprehensive performance is suitable for the platform power system in the middle power range. The single straight channel cold plate has advantages in pressure drop (ΔP) and system energy consumption and the temperature accumulation are more obvious under high heat flow conditions, which is suitable for low load scenarios. Combined with the life mechanism and vehicle thermal management framework, the cold plate structure selection and parameter classification application strategy are put forward, which can provide structural design reference for different types of new energy vehicle platforms. It is said that the Optimisation of cold plate structure affects the transient temperature control effect and has a long-term impact on the battery cycle decay rate, safety margin and system energy consumption level, which has engineering popularisation value.