Reducing wind resistance, reducing weight and improving the efficiency of power system are the main ways to improve the working efficiency of automobiles nowadays. Hidden door handles, virtual rearview mirrors, streamlined body and the use of aluminum or carbon fiber materials to reduce wind resistance or weight have been designed. Recently, however, foreign research institutes seem to be studying how to reduce the weight of electric vehicles in an impossible field, that is, motor. The Fraunhofer Institute of Chemical Technology (ICT) and the Karlsruhe Institute of Technology (KIT) recently proposed in Germany that plastics be used instead of metal enclosures of motors to reduce the weight of electric vehicles.
On the traditional internal combustion engine vehicle, the efficiency of energy conversion of the engine is low. At present, the energy conversion efficiency of the best fuel engine can only reach about 40%, and the remaining 60% of the energy will be lost in the form of heat energy, so the internal combustion engine needs more heat-resistant metal as the shell to provide protection.
Electric motors on electric vehicles have inherent advantages in energy conversion efficiency, which can reach 90% or even higher, while the remaining 10% will be consumed in the form of heat. Therefore, as long as the motor does a good job of heat dissipation, there is no need to put forward higher requirements on materials in terms of heat resistance, which makes it possible to use high-strength plastic casing motor.
In order to solve the effect of 10% heat generated by kinetic energy conversion on plastic shell, a rectangular heat sink is used around the stator to achieve more efficient heat dissipation, and a similar heat dissipation design is adopted on the rotor to achieve 80% (or even higher) of this part of heat, so as to ensure that the motor works. It will not produce too high temperature to affect the strength of plastic shell.
Ultimately, if the plastic-enclosed motor can prove to be as reliable as the metal-enclosed motor and be applied, it can not only save the manufacturing cost of the motor and improve the production efficiency, but also reduce the weight of the electric vehicle.