Like batteries, supercapacitors store and release electricity. However, rather than storing energy in the form of chemicals, they store electricity in a static state.
The two big roadblocks in the rapid adoption of electric vehicles have been their limited endurance – distance covered per unit of energy consumed – and inadequate battery charging stations. Besides, the lithium-ion batteries used in EVs today take hours to recharge. This also tests the patience of the vehicle owner. But all these issues could be a thing of the past.
In a study published in the journal Nature, researchers at the US-based Oak Ridge National Laboratory said that using machine learning, they have designed a supercapacitor material that stores four times as much energy as the best available commercial material. Calling their design a “real milestone”, they said this is the highest recorded storage capacitance for porous carbon.
They claim that their research could accelerate the development and improvement of carbon materials for use in supercapacitors (also called ultracapacitors). Simply put, more energy storage means improved regenerative brakes, power electronics and auxiliary power supplies for vehicles.
What is a supercapacitor?
Like batteries, supercapacitors store and release electricity. However, rather than storing energy in the form of chemicals, they store electricity in a static state. In the automotive sector, this allows them to collect the energy generated under braking and quickly release it within a short span of time to provide necessary boost during acceleration.
Fig 1. Improvement in supercapacitors could revolutionise the EV industry. Image via European Space Agency.
What are the advantages of a supercapacitor?
A big advantage of using supercapacitors as the power source for electric vehicles is they don’t degrade as quickly as lithium-ion batteries, thereby increasing the lifespan of an EV. The better the supercapacitor used the better the vehicle efficiency.
Supercapicitors also offer an opportunity to reduce the environmental impact of using lithium-ion power cells. They also handle wireless charging very well. When this feature is combined with their ability to charge quickly, it could remove the need to plug EVs into charging points for hours.
Since supercapacitors can be recharged many times with little or no degradation, they are often used in applications requiring many rapid charge or discharge cycles such as car booster packs and power banks. While a regular battery can handle around 2000-3000 charge/discharge cycles, supercapacitors can manage over 10 lakh such cycles. This means considerable savings in materials and costs.
These features could revolutionise the EV industry.
Disadvantages of Supercapacitors?
There are two main issues with supercapacitors. The first is energy density. The current generation of supercapacitors aren’t able to hold a large amount of charge. This makes them unsuitable to be used in electric vehicles. But the breakthrough by American researchers can help overcome this challenge. They are claiming to have designed a supercapacitor that can quadruple the energy storage capacity, a timely and welcome development for the EV industry.
The second issue is of discharging. Supercapacitors are unable to hold charge for long as of now. A supercapacitor-powered car left for a week is likely to be found with no charge. Researchers are working to overcome this challenge as well.
While it is not a given that improving storage capacity of supercapacitors will automatically mean they will substitute the large battery packs in electric vehicles, they definitely hold promise for the rapidly evolving EV industry. At this stage, EV manufacturers are desperately looking for newer technologies that can help them improve the user experience and build credibility against the Internal Combustion Engine (ICE).
