Estimated Hydraulic Resistance of Electric Bus Battery Cooling System

Abstract

Modern electric drive transport largely uses lithium-ion battery packs. Maintaining a certain temperature range allows us to reach optimal output characteristics and long battery life. To perform this task, it is necessary to include a thermostatically controlled system in the battery pack, consisting of an electric pump and radiators to cool the batteries and fluid. One of the stages in development of a thermostatic system is to estimate the pressure head required for the pump, which depends on the hydraulic resistance of the system.The modular battery pack of an electric bus with an energy capacity of 150 kWh was used as the object of research. The article describes the stepwise calculation of the hydraulic resistance of a radiator using numerical simulation in the software complex Ansys CFX, and also concerns the calculation features of the fluid flow in the pipe. Carries out a comparative analysis to study the influence of the radiator channel shape on the hydraulic resistance on the basis of which an optimal shape of the channels is proposed to provide less resistance for the fluid flow. A mathematical model of the thermostatically controlled system of batteries was developed to determine the required characteristic of the pump. The presented model allows simulation of various schemes to connect the elements of the cooling system of batteries. As a result of calculations it has been found that it is necessary to use a parallel scheme of radiator connection, which provides minimum hydraulic resistance of the system.The proposed calculation method allows us to determine the hydraulic characteristics of the cooling system components at design stage and, subsequently, using the simulation, to calculate the required pump characteristic.