The recent victory of the Toyota Supra HV-R in Japan's 24-hour Tokachi endurance race suggests that ultracapacitors will replace batteries in cars, according to industry analyst Strategy Analytics.

The Supra completed 616 laps during the endurance race, 19 more than the second placed car.

The vehicle was equipped with ultracapacitors instead of rechargeable batteries for power storage.

The analyst firm noted that the car was able to store large quantities of energy quickly from regenerative braking and apply this stored power quickly to its advantage.

German car maker BMW has also demonstrated this ability in its 'syncap' concept whereby two-thirds of total vehicle torque is generated by the syncaps enabling heavy SUVs to accelerate more quickly than before with improved fuel economy.

Batteries store electrical energy in chemical form, whereas capacitors use a pair of closely-spaced conductors to store energy in an electric field.

Capacitors are much lighter than batteries, and do not require the use of toxic materials. Furthermore, ultracapacitors have a superior charging/discharging cycle lifetime compared to rechargeable batteries.

Advanced materials such as carbon nanotubes are being investigated to further extend ultracapacitor abilities.

Kevin Mak, analyst for the Automotive Electronics Service at Strategy Analytics, said: "Impending emissions legislation will force car makers to look at energy saving technologies.

"Developments are apace to use ultracapacitors in 'stop-start' and regenerative braking systems in order to further reduce automobile fuel consumption and emissions and to power additional electrical functions.

"Full hybrid-power trains are also likely to use ultracapacitors alongside batteries, bringing a more balanced solution."

The analyst added that effective energy storage and recovery from ultracapacitors for vehicle electrical systems requires dynamic processor control and power converters, thus creating new opportunities for electronic module and semiconductor vendors.