The electrochemist Michel Cassir is Director of Research for the CNRS and is actively working in the laboratory Chimie ParisTech on the electric battery and hydrogen fuel-cell. We wanted to know more about the evolution offered by these sources of energy in the automotive industry.
1° You are working on the improvement of batteries and fuel cells for over 20 years. Where are you now?
My laboratory has initiated research in the field of fuel-cells since the late 80s. We specialize in the high temperature fuel-cell, at least 650 ° C and have become over the years one of the reference laboratories at the international level in the field.
Renault is partnered with ParisTech three years ago to launch the "Institute of Sustainable Mobility" (IMD), which addresses both socio-economic and technical aspects.
But we are actively working with the manufacturer since 1998, following an industrial contract, we have developed work on fuel-cell with solid oxide (SOFC), operating at more than 750 ° C, for use in electric vehicles as auxiliary power or traction in second instance.
More recently, we have also integrated a new field that is the production of hydrogen by water electrolysis.
2° What are the most promising technologies in a 10 years time for the propulsion of green cars? (Hybrid, electric or fuel-cell ...)?
The evolution of green mobility suggests that this pathway is really credible on both societal and industrial levels. In the medium and long term, we must be fully aware that no technology is a panacea. We will need a variety of technologies not only because of the performance and charging time, but also existing resources of raw materials and the variety of transport needs (routes, geographical and economic context). In the short term, it seems to me that the hybrid solution –by the autonomy it offers and its flexibility of use- is the most appropriate for the market...
But the launch of fuel-cell cars
, more expensive, but flexible is near (2015 to 2017 according to some manufacturers). All these parameters must be taken into account to predict the market in a decade.
In my opinion, pure electric vehicles will ride alongside hybrids. Batteries and fuel-cells will have evolved to meet specific needs depending on the type of vehicle.
3° Is lithium-ion technology starting to show its limits, will it be replaced and when?
Changes are much slower to come to the market than in laboratories... But I think the Lithium-ion technology has still some room for significant developments. But in parallel Lithium-Polymer (Bolloré) may have a specific interest as seen in the car-sharing service car in Paris. It is safer, but also more expensive and offer lower energy densities.
In the future, we will most likely arise Lithium-air
(very interesting, but still not stable). The electric battery will win tens of kilometers in the next five years, but a revolution depends on new concepts explored.
Interview by Jérémi Michaux