Saft, the high-tech industrial battery specialist, has signed an agreement with ESMA, the Russian Joint Stock Company, to co-operate in the development, production and commercialisation of supercapacitors based on ESMA’s technology. The agreement enables Saft to add new supercapacitor technology to its portfolio of battery technologies.

Initial applications will be for the starting up of heavy duty diesel engines used in industry or public transport, in particular for low temperatures or in frequent stop-start usage, but Saft’s expectation is that their new products will find numerous other applications for peak power and energy storage.

Saft is aiming initially at the US market, and the first results of its new agreement will be seen later in 2009, when Saft’s US manufacturing facility in Valdosta, Georgia, will commence production of a new generation of asymmetric nickel supercapacitors that will work in combination with batteries on heavy vehicles in a large variety of markets including, but not limited to, industry or public transportation. By providing more reliable starting power for large diesel engines in stressful conditions the supercapacitors will allow the vehicle battery to be optimised for the application.

In addition to the co-operative agreement with ESMA, Saft has also signed a distribution agreement for the supercapacitors with KBi (Kold Ban International) the US company specialising in diesel engine starting systems that is already an established ESMA distributor for North America.

‘ESMA’s asymmetric nickel supercapacitors are recognised in independent laboratory tests as offering the best low temperature engine starting performance currently available’ says Xavier Delacroix, the general manager of Saft’s IBG division. ‘This co-operative agreement adds an exciting new dimension to Saft’s range of battery technologies, while our US manufacturing presence and global footprint will help bring ESMA’s supercapacitors to a much wider market.’

ESMA’s asymmetric nickel capacitors feature one battery electrode mated with a double layer charge storage (capacitor) electrode. This combination, says its maker, offers a number of advantages over the standard, more common symmetric design including improved safety, higher specific energy, more stable operating voltage, lower materials and manufacturing costs, and voltage self-balancing in high-voltage strings of capacitor cells. The design has an important synergy with Saft’s manufacturing capabilities since the construction is similar to that used in nickel-cadmium cells, so ESMA’s supercapacitors can be manufactured on existing Saft production lines.

Since a supercapacitor stores energy electrostatically, with no physical changes taking place, it can have a service life of a million or more charge/discharge cycles, with no maintenance required. Furthermore, the performance of a supercapacitor remains stable over a very wide temperature range (typically -40°C to +70°C), which is what makes them so well suited for starting up heavy diesel engines at low temperatures.

The advantages of capacitors as storage lie in their robustness and ability to discharge more or less instantaneously, but their very low capacity renders them useless for power purposes. But the advent of supercapacitors (aka ‘ultracapacitors’) based on activated carbon structures with an enormously extended surface area has increased the available charge capacity from microfarads to farads (a factor of a million) and even to kilofarads. (A one farad capacitor would be able to deliver one amp at one volt for one second). Applications are likely to use battery-capacitor hybrids that will combine the capacitor’s advantage of instant response with the battery’s ability to recharge it immediately after discharge.

Seven or eight years ago Saft contemplated the manufacture of supercapacitors that could employ manufacturing techniques already used in the production of its lithium-ion batteries, but the project did not get past the prototype stage.