Will we be driving only electric cars in twenty years' time?
The first, purely electrically-driven compact and sports cars are already on the market, but they are much more expensive than their classic diesel or petrol engine counterparts and have a range of no more than 100 kilometres. Only light, high-performance and cheap lithium-ion batteries will help electric cars achieve a breakthrough. Will such electricity storage devices reach production standard in the near future?
A million electric cars could be driving on German roads by 2020, optimists say. To begin with, the aim is for electric vehicles to establish themselves against petrol-driven models in city traffic. “For that, we need electricity generated from renewable sources and new vehicle concepts,” says Prof. Dr Horst E. Friedrich, Head of the DLR Institute of Vehicle Concepts in Stuttgart.
Cheap batteries with greater power
This cannot be done with batteries which still cost at least 10,000 Euros for a Golf-class vehicle. This is why battery manufacturers around the world are pursuing the same objective – greater power from lighter and cheaper batteries. The current undisputed market leader is the Japanese company Panasonic, whose batteries are driving hundreds of thousands of hybrid cars. European industry is aiming to catch up. Companies such as BASF, Bosch, Evonik, Li-Tec and VW are preparing for the billion-Euro market in electric vehicles through cooperative ventures.
Up to 30 percent more power with nanotechnology and iron phosphate
The state-of-the-art battery cathode (the positive pole) consists of a one-third mix of metal oxides. It is composed of cobalt, manganese, aluminium or nickel oxide, each coupled with lithium, the source of ions. “But we don’t yet know who will build the best batteries in future,” says battery expert Andreas Jossen from the Centre for Solar Energy and Hydrogen Research (ZSW) in Ulm. In addition to many nanostructured materials, lithium iron phosphate looks very promising. It offers a high level of protection against short circuits when used as the battery cathode. Iron phosphate is also significantly cheaper than the cobalt compounds in widespread use today.
The negative pole of the lithium-ion battery can also be improved. Today, the battery anode mostly consists of graphite. A battery with an anode consisting of tiny silicon nanowires could deliver at least 30 percent more electricity. The team of materials researcher Helmut Föll from Kiel University recently demonstrated the production of such nanostructures using a fast and cheap process. Initial tests confirm the potential increase in power, although it might still be a few years before this patented technology is ready for production. “Such progress will increase the energy density of lithium-ion batteries. I anticipate an energy density of 300 watt-hours per kilogram in the next few years,” says Friedrich. At present, the best batteries measure up to 200 watt-hours per kilogram.
Internal combustion engine still has potential
Petrol-driven vehicles will not disappear from our roads in the coming decades either. However, because of high oil prices and growing competition from electric vehicles, it is set to become more refined. Thanks to lightweight construction, improved combustion processes and exhaust treatment methods for petrol and diesel engines, there will not just be small numbers of cars with good fuel economy but whole fleets with consumption values of three litres and less per 100 kilometres. In twenty years' time, we are likely to see both vehicles with internal combustion engines and electric cars on our roads.
The DLR energy question of the week in 'The future of energy' Year of Science
The Federal Ministry of Education and Research (BMBF) has given the Year of Science 2010 the motto 'The future of energy'. For this reason the science journalist Jan Oliver Löfken will this year answer a question on the subject of energy in his blog each week. Do you have a question about how our energy supply might look in the future? Or do you want to know, for example, how a wave power plant works and how it can efficiently generate electricity? Then send us your question by email. Science journalist Jan Oliver Löfken will investigate the answers and publish them each week in this blog.