Challenge Bibendum - The electric car becomes a reality

Understanding Sustainable mobility	DISCOVERING THE SOLUTIONS	NEWS AND PUBLICATIONS	Events	Challenge Bibendum	Get involved	Michelin's involvement
Mobility and sustainability Challenges Making it happen Glossary Links	Energies & vehicles Urban mobility Connected mobility Road safety Challenge Bibendum Booklets	News and publications REPORT : Sustainable mobility in the US Report: Road Transport	Shows Calendar of Events	About Challenge Bibendum Berlin 2011 Past events	Avoid traffic jam Save Fuel Be a safe driver Car sharing/pooling Calculators	Commitment for sustainable mobility Performance and responsibility Products and services

Home DISCOVERING THE SOLUTIONS Energies & vehicles The electric car becomes a reality

The electric car becomes a reality

06-7-2010 by

Resume:
Lithium and lithium-ion batteries are ideal power sources for vehicle applications due to their unique features in terms of energy density.

The concern on global warming, the continuous increase of the oil cost, the need for efficient, sustainable transport, the call for the introduction in the road of a large fleet of zero emission or of controlled-emission vehicles. The full electric car (EV) operates with an electric engine, while the hybrid car (HEV) and the plug-in hybrid car (PHEV) share electric and combustion engines. All these vehicles require a battery for powering the electric engine. Lithium and lithium-ion batteries are ideal power sources for vehicle applications due to their unique features in terms of energy density.

What is a lithium-ion battery ?

In its most common configuration a lithium-ion battery is formed by a graphite anode and a transition metal lithium oxide LiMO₂, e.g. lithium cobalt oxide, cathode separated by an electrolyte consisting of a solution of a lithium salt in a liquid mixture of organic carbonates.

Lithium ions shuttle from the cathode to the anode across the electrolyte solution with a simultaneous release and acceptance of electrons that power the external load. Lithium-ion batteries are the power sources of choice for popular portable electronics, such as mobile phones, note books, Mp3 … and are currently produced at a rate of several billion units per year.

Can the present lithium-ion battery technology be extended to EV and HEV markets?

Although established commercial products, lithium-ion batteries still need further improvements to meet the requirements of emerging markets, such as those directed to the progress of sustainable road transport. The present lithium-ion battery technology does not yet allow their penetration on those markets. Enhancement in energy density and, especially, in safety level, as well as decrease in cost, are needed. These are not easy tasks and large investments are worldwide devoted to make them real.

Reasons for improving energy density

The energy density is the amount of watt-hour that the battery may produce by unit weight or unit volume. Obviously, for the use in a passenger car, the battery should be as light and as small as possible. Presently, lithium-ion batteries can offer values of about 150 Wh/kg and 300 Wh/liter, that are still not adequate for assuring long driving range with a single charge. Therefore, success in the EVs and HEVs markets requires new types of batteries with energy density levels four or five times higher than the present ones.

Why lithium/sulphur?

Large improvements in energy density may be only obtained by the development of new lithium battery technologies. Among these, the lithium/sulphur battery has a key role. This battery, in fact, provides in theory a significantly higher theoretical energy density than that offered by common lithium-ion batteries, namely 2,500 Wh/kg versus 500 Wh/kg. This implies that with the same weight, the lithium/sulphur battery can assure a driving range three times longer that that provided by the common lithium battery systems

Major players are positioning themselves for the development of the lithium/sulphur battery
A number of academic and industrial laboratories have research activities on the lithium/sulphur battery. However the practical development of this battery has so far been prevented by a series of issues involving, among others:

sulfide dissolution at the cathode, that limits the cycle life;
reactivity of the lithium metal anode, that induces safety hazards and
poor electronic conductivity of the active cathode material, that reduces the low rate capability.

Recent success opens the route for the practical exploitation of the Li/S battery

Recently a new type of lithium sulfur battery has ben reported by an Italian research team at the University of Rome Sapienza. The battery exploits a totally new chemistry involving a safe tin-carbon nanocomposite (to replace the reactive and unrealable common lithium metal anode), a plastic-like gel-polymer membrane (to replace the unstable and flammable common organic electrolyte solution) and a carbon/lithium sulfide composite (to replace common sulfur cathode). This battery is intrinsically safe, offers long cycle life and provides values of energy density three to four times higher than that offered by common lithium-ion batteries. It is expected that this new, high-energy battery may soon finds its way to large-scale, industrial production.

For further information on the lithium/sulphur battery :

Ahn, H-J , Kim, K-W and Ahn, J-H, Lithium Sulfur Cells, Encyclopedia of Power Sources, Elsevier, 2009, 155-161

J. Hassoun & B.Scrosati, Angew. Chem. Int. Ed. (2010) 49, 2371

http://www.wiley-vch.de/vch/journals/2002/press/201010press.html

Read also in this section:

- "EcoMeter Connect": Supporting Green Driving, Facilitating a Greener Society
- Driving GM Builds Commitment for Gas-Friendly and Gas-Free Driving
- Lithium-based Batteries for Electric and Hybrid-Electric Vehicles
- Recent development program for fuel cell technology in Japan
- Air Liquide and the Hydrogen issue
- Progress of Internal Combustion Engines
- Surpercharging automobile engines
- Batteries for Electric and Hybrid Electric Vehicles
- New homogeneous combustion processes
- Engines downsizing
- Fuel cell technology, an innovative powertrain solution

Categories: Battery - Energy - Electric vehicles - Hybrid vehicles

Keywords: battery - electric -

IN THIS SECTION