The Secret is in Supercapacitors


When Elon Musk, the creator of Tesla, came to the United States, he was doing research on advanced and highly energy dense materials called supercapacitors at Stanford. He reiterated his interest in these components, “If I were to make a prediction, I’d think there’s a good chance that is not batteries, but super-capacitors.” He made these remarks as he spoke at the Cleantech Forum inSan Francisco when asked about the future of electric vehicles.

Supercapacitors perform a similar function as batteries, where they both are able to retain and store energy. In electric vehicles though, supercapacitors are able to efficiently store large amounts of energy that occurs during regenerative braking. When the need for acceleration comes, these supercapacitors would be able to supply the required energy burst at a much faster rate compared to ordinary batteries with a lower system energy loss.

The most common design is called the electric double-layer capacitor, where the electrochemical capacitor with very large energy density. The energy density of a supercapacitor is a hundred times greater than ordinary battery systems. Typically, a battery has a capacitance of tens of millifarads, while a supercapacitor of the same size has the capacity to store several farads.

Unfortunately, hybrid vehicles on the roads today use batteries because supercapacitors still are unable to store the energy storage per pound. For supercapacitors to provide the same amount of energy as batteries for electric cars, as there is a need for a large amount of surface area. This issue though can be resolved through the use of nanotechnology that increases the available surface area in large amounts. This can be designed in a way were conductive surfaces store electrons for rapid use, dispensing with the need to create large expensive thermal management systems to properly control the chemical reactions in the production of energy.

There are two aspects of current research that is being subject of focus and intensity. These include performance improvement together with overall cost. Back in 2000 a 3 kF capacitor would cost around U.S. $5,000 but in 2011, the same supercapacitor now merely costs U.S. $50. Other considerations being sought improved include the high self-discharge rate of supercapacitors and low maximum voltage, thus requiring series connections to achieve higher voltages.

The technology race is still ongoing and we are all in for the ride.