Experimental Investigation of Power Performance and Thermal Behaviour of the Powertrain in Battery Electric Vehicles

This research explores the power performance of a Battery Electric Vehicle

(BEV), specifically focusing on the MG ZS EV model (2023). The study aims to assess

the performance of the BEV’s powertrain system across a range of velocities and

analyse the thermal behaviour of its powertrain components. Testing was conducted on

both a chassis dynamometer and in real-world driving conditions, maintaining constant

speeds of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 km/h. When comparing power

consumption on the chassis dynamometer to real-world driving at 70, 80, 90, and 100

km/h, it was observed that the power demand on the road was higher by 14.58%,

23.18%, 36.17%, and 42.58%, respectively. This increase is attributed to aerodynamic

drag, which becomes more significant at higher speeds. The corresponding aerodynamic

drag forces at these speeds were calculated to be 53.18, 90.50, 156.43, and 198.36 N,

respectively. A quadratic relationship between driving power on the chassis

dynamometer (𝑃𝐷𝑦) and on the road (𝑃𝑅𝑑) was determined, resulting in the equation:

𝑃𝑅𝑑 = (1.03 × 10−4)𝑃𝐷𝑦

2 + 0.47415𝑃𝐷𝑦 ,with an R-squared value of 0.9979. This

equation allows for the prediction of driving power on a dynamometer to real-world

driving conditions. In terms of thermal behaviour, the powertrain components were

classified into two groups. The high-voltage battery pack showed a slight increase in

temperature, ranging from 33 to 35.5 °C. Meanwhile, the traction motor and inverter

exhibited a wider range of temperature accumulation depending on power demand, with

operational temperatures between 34 and 64 °C.