Optimization analysis of DC charging pile heat dissipation system for electric vehicles


In order to solve the problem of heat dissipation of charging pile under the new demand conditions such as increased output power, complex internal structure and harsh outdoor working environment, it is necessary to analyze the thermal characteristics of charging pile. This paper takes 150kW DC charging pile as the research object and establishes its thermal characteristic model. The finite volume method is used to analyze the flow field and temperature field in the forced air-cooled charging pile, and the system ventilation and cooling scheme is optimized to compare and analyze the cooling effect of the charging pile under the actual ventilation and the improved ventilation scheme, and the effects of factors such as the pile fan air volume and output power on the temperature field of the charging pile are further studied. The results show that the improved ventilation optimization scheme is more conducive to reducing wind resistance and accelerating system heat dissipation, which provides theoretical guidance for DC charging pile product development.

It is estimated that the reliability of components will be halved for every 10℃ increase in ambient temperature [2-6], and the failure of components will affect the reliable charging of the whole charging pile. Therefore, efficient heat dissipation design is an important part of the structural design of charging pile equipment, and it is also one of the important factors to ensure the stable operation of the equipment.
Currently, Computational Fluid Dynamics (CFD) has become an important means of analyzing thermal simulation problems, and numerical analysis of CFD simulation can provide an intuitive understanding of the velocity distribution, temperature distribution, and pressure distribution at any location in the simulation model in advance.

The 150kW DC charging pile is composed of power module, DC bus, AC/DC insulation detection system, auxiliary power supply, inlet switch and shell, etc. The modeling software is used to establish a three-dimensional model of the charging pile, which has the external dimensions of 1880mm×786mm×695mm, and the structure is shown in Figu
Internal structure of charging pile leipole axial fans
This DC charging pile adopts EVR700-15000 power module, and the module itself has 4 fans blowing from the front side to the back side of the module, so the charging pile adopts the forced air cooling by installing extractor fan on the back side of the pile body. Among many cooling methods, the cooling capacity of forced convection air cooling is much better than natural convection air cooling, and it is simpler and easier to realize than water cooling and oil cooling, with higher reliability, and it is the main cooling method for commonly used outdoor cabinet devices. The main heat dissipation method for commonly used outdoor cabinet devices.

CFD simulation analysis model of charging pile

The power module consists of front and rear air inlets and outlets, upper and lower aluminum-zinc-plated plates, and internal heat sinks, etc. The 10 power modules are arranged in order from bottom to top, the DC bus, AC and DC detecting part and auxiliary power supply are installed in the middle of the 8th module and the 9th power module, and AC contactors and inlet switches are installed at the bottom of the power module. The finite volume model is shown in Figure 2. The three-dimensional model is effectively simplified by omitting the parts with little change in heat exchange and airflow. The actual ventilation of the charging pile adopts the ventilation path of installing fans on the back side and the top of the pile body to extract air, and the outside air enters the module from the two air inlet ports of the pile body and the air inlet holes on the top and bottom of the pile body, and then passes through the ducts in the module to discharge the heat by the rear side outlet.
CFD simulation analysis model of charging pile
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