Secretive company claims battery breakthrough

A secretive Texas company claims to have developed a technology that could make traditional batteries a thing of the past and power devices of all sizes ranging from cars to mobile computers.

The company, EEStor, says it could ship a system for use in an electric car as soon as this year, according to a report in MIT Technology Review .

The first product will be an Electrical Energy Storage Unit (EESU) weighing less than 100 pounds and capable of driving a small electric car for 200 miles – and then recharge in less than ten minutes, the company claims.

At US prices, the unit could power a car for 500 miles on $9 worth of electricity.

The EESU is described as a ‘battery-ultracapacitor hybrid’. An ultracapacitor is a more capacious version of the tiny capacitors used in electronics, which act as a reservoir of charge, rather like a lake that is fed and drained by a stream of water.

A simple capacitor consists of two closely spaced plates separated by an insulator, or dielectric. Different dielectrics have a profound effect on how much charge can be stored.

Ultracapacitors with a high energy density have been developed for hybrid vehicles that boost efficiency by harvesting braking energy as electricity. Their advantage is that that can charge and discharge very quickly but they cannot store anything like as much as electricity as a battery.

EEStor, according to the Technology Review, claims have got round this that by using a dielectric based on “barium-titanate powders” of a constituency capable of withstanding a voltage across the capacitor of 1200- 3500 volts.

The result is a device capable of storing 280 watts-hours per kilogram compared with 32 watt-hours per kilogram of a lead-acid gel car battery.

It is also rather more than twice the energy density of the lithium-ion batteries used on laptops – which means they would easily meet the industry target of lasting a working day without a recharge.

Richard Weir, EEStor chief executive, told Technology Review that the system can be “tuned” to applications at widely different scales – right down to driving a heart pacemaker.

It was unclear whether a small application like a laptop power unit would require high voltages but they are not unknown in consumer electronics – a cathode ray tube typically uses several thousand volts.  But clearly there would be safety issues, even in a car.

EEStor’s claims have been met with some scepticism, according to MIT Review.