The battery is the heart of an electric car - and also the number one object of research. Now there are signs of a breakthrough with lithium and air. But it will take until then a little bit.
Hauke Schrieber from the electric car is ready. Models such as Mitsubishi i-MiEV (photo) or Nissan Leaf show that construction and operation represent no more problems. Crucial weak point but are still the batteries: they are too expensive and too hard to allow enough range to have long load times and large temperature sensitivities. Modern lithium-ion batteries, as used for example in leaf weigh 250 kg and more, their energy density of about 170 watt hours per kilogram allows a maximum range of 160 kilometers. That's enough for many drivers though - but only for the second car.
The Karabag Fiat 500E runs with a lithium-polymer battery - including in large-AUTO BILD endurance test. To make the battery-electric car is really suitable for mass production, more powerful batteries need to be developed. After interim solutions such as lithium-polymer (used already in Karabag new 500E), the next generation of batteries produced in lithium-sulfur base. It could allow a range of up to 300 kilometers (see table below). The final breakthrough in battery technology, scientists expect in a good ten years from the lithium-air battery. Here, the cathode is replaced by oxygen from ambient air. The anode is metallic lithium. This makes the battery lighter and more compact.
Read also: The cost of the Nissan Leaf
But researchers still face many challenges. Only one problem: Moisture in the air can lead to an explosive reaction. Lithium-air batteries, therefore, need protective membranes that keep water reliably, but oxygen to pass through. If successful, the energy density is about ten times higher than currently installed batteries. And then with a significantly lower weight ranges of more than 500 kilometers would be possible. However, coverage is not all. Equally important is a long life, high load capacity, low weight and especially cost competitive. Currently, only the costs for an electric car battery around 10,000 €. The Federal Ministry for Education and Research supports the projects that are working on a series production of lithium-air batteries, with around 5.6 million €. In about two years should be clear whether and when lithium-air batteries are used in electric cars.
Energy storage for electric cars
Battery energy density in Wh / kg weight in kg Range in km in electric cars
Lithium-ion * 170 150 160 since 2007
Lithium-polymer 70 95 ** 180 since 2010
Lithium-sulfur 300 150 280 2020
Lithium-air 1000 80 500 2025
* = Values of the Nissan Leaf, ** = values from Kar
