lithium sulfur battery
Image credit: Oxis Energy.

Many years ago, I learned of a technology that could turn the energy industry upside down — The lithium sulfur battery. It could achieve a gravimetric energy density of 400 Wh/kg. The majority of electric vehicle batteries are well under 200 Wh/kg. This means that lithium sulfur battery technology could at least double EV range without adding a single pound of weight, and quadruple most of them. Imagine a Tesla Model S that could travel up to 800 miles per charge!

lithium sulfur battery
Image credit: Oxis Energy.

Oxis Energy is going to start selling lithium sulfur batteries in 2016, aiming for a cost of $250/kWh by 2020. This is inexpensive compared to current lithium-ion batteries which cost $400-$500/kWh, however, their prices can (and probably will) decline by 2020 as well. As incredible as the range implications I mentioned above are, the financial implications are even greater. $250/kWh could slash thousands from the cost of electric vehicles, making them much more competitive with gasoline-powered cars.

‘The overall cost of the materials is less – an example of this is sulfur, key to the technology, which cost under $200 per tonne,’ said Howells, adding that the ‘predicted costs of lithium sulfur when production is ramped up is lower than competing lithium-ion technologies.’

The battery technology is undergoing testing at the Culham Science Centre in Oxford as part of Project Helios. The test system is a solar power supply utilizing a 3.8 kW 16 panel PV array, a 48 volt, 3 kW Oxis battery pack, and an SMA Sunny Boy inverter. It is currently being used to recharge a driverless vehicle. The current battery achieves an energy density of 300 Wh/kg, but they anticipate an increase to 400 Wh/kg in 2016.