Dipl.-Ing. Thorsten Opel (né Balzer), University of Bayreuth, GERMANY

Dr. Nico Langhof, University of Bayreuth, GERMANY

Prof. Dr.-Ing. Walter Krenkel, University of Bayreuth, GERMANY

Future mobility concepts like electric powered vehicles demand for new braking technologies and brake disc concepts. Due to the technological progress regarding the recuperation capabilities of electric vehicles, friction brakes are merely needed for complementary braking and more importantly for emergency braking manoeuvers. Consequently, new brake disc designs are viable in which for example the mass of the brake discs can be reduced. Due to the fact, that the brake discs in electric powered vehicles aren’t used as frequently, the corrosion of the brake discs and brake pads are problems which have to be coped with. Thusly the use case or rather the (performance) requirements for brake discs for electric powered vehicles are very different compared to brake discs for cars with internal combustion engines.

A new concept in the form of a metal-ceramic hybrid brake disc is propagated for the use in electric powered vehicles. It consists of an aluminium carrier body which is lined with ceramic friction segments on the friction surface of both sides. For the friction segments a short fibre reinforced ceramic matrix composite (in particular a carbon fibre reinforced silicon carbide: C/SiC) is used. The outlined concept allows for a light-weight, corrosion resistant and economically viable emergency brake with outstanding friction properties for the use in electric powered vehicles. An overview is given on the potential application areas and on the design, construction, manufacturing and testing of said hybrid brake disc.

A potential use case of a mid-class sedan with a mass of around 1.8 t and maximum travelling speeds of up to 200 km/h is taken as a basis for the design and construction of a metal-ceramic hybrid brake disc prototype. This prototype was tested on the dynamometer test bench at the University of Bayreuth under emergency braking conditions. Different characteristic values like wear, coefficient of friction and different temperatures were measured. The results are compared to results of standard commercially available brake discs (e. g. cast iron and carbon ceramic brake discs). Furthermore, possible joining methods were evaluated and thermomechanical characterisations of different joints were conducted.