Battery research will give electric cars the same range as petrol onesPublished On: Thu, Apr 7th, 2011 | Transportation Science | By BioNews
Danish experts have suggested that more research into batteries was needed to give electric cars the same range as petrol cars.
The Achilles’ heel of the electric car remains its limited energy density of the batteries, which will only sustain short drives.
That is where Lithium air (Li-air) batteries come into play.
“If we succeed in developing this technology, we are facing the ultimate breakthrough for electric cars, because in practice, the energy density of Li-air batteries will be comparable to that of petrol and diesel, if you take into account that a combustion engine only has an efficiency of around 30 percent,” said Tejs Vegge, senior scientist at Riso DTU.
Now – 110 years after the first electric car, – battery technology, combined with the effect electronics and the electric engine, have come so far in performance, size and price that the electric car is again becoming interesting.
The electric car does not pollute locally and it can, if used cleverly, be utilised to introduce more renewable energy into the electricity supply.
Today, battery packs are expensive and are only able to store a relatively low amount of energy. Researchers all over the world are working to change that.
For electric cars to become the consumers’ preferred mode of transport, the battery capacity must be significantly increased.
The most promising electric car batteries are based on the metal lithium (Li). Lithium is a soft, silver-white metal – the lightest of all metals. Lithium is extremely reactive and corrodes quickly in a humid atmosphere. There, lithium is typically stored under kerosene to avoid contact with oxygen and water.
The lightness is one of the strengths of lithium.
Traditional car batteries are based on lead, which is one of the heaviest metals in existence.
To reduce the weight of batteries, lithium is the way to go. Just look at the prominence of rechargeable Li-ion batteries in e.g. mobile phones, cameras and MP3 and MP4 players. These batteries have the highest energy density among rechargeable batteries.
Lithium is naturally occurring with approx. 65 g per tonne in top soil and approx. 0.1 g per tonne of water and can be extracted from soil as well as water, but if the lithium content is small, the extraction is costly.
The fight over the world’s lithium resources will intensify in the future, but the upside is that the lithium part of batteries can be recycled, so when the batteries are worn out, the lithium can be extracted and form part of a new battery.
If batteries with an energy density this great become a reality, one could easily imagine electrically powered trucks.
Li-air batteries are thus a promising research area, but there are many research challenges to overcome before the batteries find their way to the electric cars.