From mechanical to regenerative braking - Implications of the transition towards electric mobility on aspects of deceleration and tribological brake additives

Abstract

New concepts of mobility, as part of societal change in form of mega trends, are leading to disruption in the automotive industry. Above all the rise of electric mobility is creating changes in structures within the whole sector supply chain. While still only modestly in use up to now, the majority of automotive sector specific forecasts estimate a market share for electric vehicles of 50% and above by 2030. All major automotive manufacturers invest massively in electric driving concepts. In this context, the brakes are one of the most important pieces of safety equipment on a vehicle. Whereas in internal combustion engine vehicles, the braking system is mostly based on creating abrasion resistance thereby inducing the deceleration, brakes in electric vehicles aim at avoiding the latter. Through regeneration, the electric braking system can convert the kinetic energy previously lost and convert it into electric energy subsequently used for acceleration of the vehicle. This shift in paradigm is causing manufacturers to rethink from the scratch the requirements, possibilities and layout of brake systems. At the same time, the given legislation demands compliance with existing standards that even though presumably outdated, may impede further commercialization of beneficial changes. As a consequence, these developments also have a strong impact on tier 3 suppliers such as producers of additives for friction materials. Aim of this thesis is to provide an overview over the fundamentals of friction braking, regenerative braking and presumably new necessities and challenges, followed by pointing out subsequent implications on friction materials currently in use.