The battery thermal management system has become an important aspect of the development of electric vehicles (EVs) which are widely considered as a promising option instead of internal combustion based vehicles (ICEs) for reducing the climate change effects. Particularly, advances in Lithium ion batteries with high energy density are considered key elements for wide spread acceptance of EVs. Batteries with larger energy densities exhibit the thermal issues, which creates decreased performances at higher operating temperatures and eventually turning thermal runaway into fire or explosion. In this paper, a novel design is presented with mineral oil as a coolant with channel guide. The temperature distribution is recorded at various coolant mass flow rates and pressure drop variation is discussed.

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The objective of this study was to numerically investigate the heat transfer characteristics of a 36V electronic control unit (ECU) system of an electric bicycle and to validate the experimental data. The temperatures of the ECU heatsink, seven metal-oxide-silicon field effect transistors (MOSFETs) and two capacitors of the 36V ECU system were numerically derived under variable operating conditions including power dissipation, thermal grease, ambient temperature and heatsink material, to analyze the heat transfer characteristics. When the thermal conductivity of the thermal grease increased from 0.01 W/m • C to 3.0 W/m • C, the temperatures of the seven MOSFETs and the two capacitors decreased by 51.245% and 3.58%, respectively. When the total power dissipation increased from 2.57 MW/m 3 to 4.26 MW/m 3 , the temperatures of the ECU heatsink, seven MOSFETs and the two capacitors increased by 20.95%, 30.31% and 21.54%, respectively. Furthermore, increasing the ambient temperatures from 30 • C to 40 • C resulted in an increase in the temperatures of the ECU heatsink, MOSFET and capacitor by 24.75%, 9.93% and 22.04% respectively.. These numerically derived temperatures for the MOSFET and the ECU heatsink were validated with the experimental results within a range of 7.2% and 1.7%, respectively. This confirmed that the applied numerical model was valid.Energies 2018, 11, 2506 2 of 17 vehicles. In addition, they concluded that the strong demand for gasoline-powered motorcycles and bans on electric two-wheelers due to safety concerns in urban areas are the largest resisting forces that limit the market growth of electric two-wheelers [7]. Jones et al. analyzed the motivation, perceptions and experience of electric bicycle owners in Europe. They concluded that electric bicycles motivate people to cycle who would not ride a conventional bicycle and that they would change the traveling behaviors of the cycling public [8].Many electric bicycles are hybrids and use human power as well as electrical power. An electrical powertrain consists of the battery charger, battery pack, electronic control unit (ECU), including the motor controller and the driving motor. Due to the rapid development of lithium-ion (Li-ion) battery technology, most electric bicycles are equipped with these batteries with a high-power density. Moreover, these batteries are sensitive to the environmental temperature and to the input/output current [9,10]. The ECU with the driving control motor unit is another important part of electric bicycles and is located between the battery and the motor (Figure 1). The ECU controls the motor speed, charging performances and several other functions, which controls the overall efficiency of the bicycle [11]. The capacitors in the ECU assist in maintaining the supply of a steady consistent current, resulting in a smooth and improved lifetime of the driving motor. This unit also supplies power to other electronic accessories such as the lights, horn and speed indicators. Thus, the performance of the ECU is crucial in det...