Electric vehicles are here, on the market today, with more to come from nearly every major automaker by the early 2020s. While demand isn’t quite there yet, Tesla has scored major points with its success, not too far from producing its 1 millionth vehicle in the next year. While the market is changing, new engineering breakthroughs are sure to change EV culture. While some major hurtles still to overcome include extending battery range, building cheaper batteries, handling power degradation in cold temperatures, and lack of recyclability for older batteries, super capacitors are gaining traction as a viable option to aid in some of these areas.
Typically, a capacitor is used in a hybrid or electric vehicle to hold recaptured energy from regenerative braking. Capacitors hold a charge, but unlike a battery, they cannot hold the charge for very long. Energy recaptured and held in capacitors from regenerative braking is usually used shortly after when a driver hits the accelerator pedal to speed up, or in other ways by using technology within the cabin. While effective, technology on capacitors only went so far for a long time. Today, as engineering development continues, the “super” capacitor is in development, which is meant to take the basic concept of taking recaptured energy to the next level.
Every fully electric vehicle, be it a Tesla Model S, X, or 3, Chevy Bolt, or Nissan Leaf, all operate off the notion of a main battery holding the charge for the vehicle. The best batteries on the market can hold just under 340 miles, and those are on more expensive models. Most vehicles have a range in the 200-250 mile ballpark, which is enough to sustain a lot of local trips to work. Despite this, the mileage is not compelling enough for many to consider an EV because they cannot achieve the same longevity as a gas engine, which can easily bring you 350-500 miles on a full tank of gas. When you need to refuel, it takes minutes, compared to hours, in an EV. Super capacitors hope to help change this.
Batteries store energy by utilizing chemical reactions within the battery and use expensive metals such as cobalt and lithium, which makes them difficult to recycle. Capacitors are made of different materials that are much more environmentally friendly and store their energy in an electric field, similar to how balloons hold static electricity. The issue that has made the future of capacitors seem grim for many years is that they only hold about 5% of energy per kilogram that a lithium ion battery can. In other terms, a very bad energy storage density. The main bonus of using capacitors though, as utilized in regenerative breaking, is that they charge incredibly fast in comparison to the typical battery.
In recent years, engineering breakthroughs have broken the barriers that have made capacitors so inefficient through the development of a new polymer mesh material that can be used in making a capacitor. The dielectric properties of the material are tested and proven to be 1000 to 10,000 times greater than most existing conductors, bringing energy density up to as much as 180 Whr/kg (Watt Hours per kilogram), compared to a typical 10 Whr/kg.
While this new material is still in testing and development phase, this proves a great future of possibility for the new, so called “super” capacitors. Utilized with typical batteries, super capacitors can greatly accelerate recharge times and help bring overall charge range above 400 miles per charge in a vehicle, depending how they are integrated into the system. A 400 plus mile range is deemed acceptable to most auto critics and thought to be a major compelling factor for those considering the purchase or lease on an electric vehicle.
At the current state of the market, these new super capacitors will not find their way into EVs until sometime within the next decade, so electric vehicles will continue to be built off of pure lithium ion battery packs for a few more years. As forecasted by some, the flood of new EVs to the market by many manufacturers in the early 20s could cause a major disaster for certain brands if demand remains low, but as super capacitors find their way into vehicles, the case may become more compelling as range increases and prices drop. Elon Musk predicted this years ago, and as development gains speed, this could be a solution to the many problems that modern battery electric vehicles face.