Electric cars tend to become the emerging generation of automotive vehicles for the next decades. One of their main features is that they are rather silent and then present issues as: must electric cars be sonified for preventing pedestrians from dangers? If necessary, what kind of sound signal is to be put to fulfill safety rules without contributing to the environmental pollution ? Moreover, because the starting point of this thought is nearly a blank page, it opens a large field of experimentation on different aspects of sound design: innovative approaches to create sounds in interactive configurations, role of sound to convey functional informations, aesthetics qualities or even emotional feelings, etc. In the frame of an industrial collaboration, we tried to handle these questions by examining the state-of-the-art in that domain, defining the specifications that sound has to comply with (warning for direction and speed, driver feedback of speed and functioning, various branding components, etc.), prototyping various ideas of interactive sonification, and initiating evaluation experiments especially in terms of primary functions (notification of presence and approaching speed). Some results from different steps of this work together with overall reflections and perspectives on the general topic will be presented and discussed.