In recent years, decreasing vehicle costs and more options from car manufacturers have driven a steady increase in electric vehicle (EV) sales. With about 97 percent of battery charging taking place at work or at home, drivers of electric cars willing to accept that they may need to charge up over lunch when traveling longer distances.
The number of electric vehicles out on the streets is expected to keep multiplying as governments continue to incentivize clean energy and manufacturers find ways to make their cars more accessible. A big part of what is making that possible is ongoing innovation in battery technology, driven by demand for smaller, lighter, safer batteries that charge faster and last longer.
As the U.S. recommits to decreasing its dependence on fossil fuels and countries around the world strive to meet objectives set by the Paris Agreement, the pressure is on for advancements in science and technology that will make energy cleaner and more efficient. For the electric vehicle industry to make real progress, it needs to go beyond producing electric cars to enabling trucking and mass transportation to shift away from gas and diesel.
While consumers can shrug off the charging limitations of today’s EVs as a minor inconvenience, they are simply unacceptable for commercial industries like long haul trucking. Supply chains are meticulously planned and managed for maximum efficiency. Even minor delays, such as a few hours here and there to charge up, can result in an extensive increase in costs - and an 18-wheeler full of cargo requires significantly more power to move down the highway than a Tesla Model S.
Advances in battery technology will keep improving efficiency and charge times, but it won’t get us anywhere near what’s required to make it feasible for trucks and buses to “go green.” For electric vehicles to gain any meaningful foothold in commercial transport, the burden of charging would essentially need to be eliminated, and that will require a major breakthrough in semiconductor technology.
Most electronic devices, large and small, require electrical power to be converted from one form to another. At the heart of every modern power converter is the semiconductor power switch, which determines the performance of the whole system. While silicon (Si) has long been the dominant power switching semiconductor material, it fails to meet the performance demands of modern high-power applications such as electric vehicles, solar photovoltaics, and smart power grid distribution. Silicon carbide (SiC) has stepped in to provide some incremental improvements over Si, and it’s what is used in EVs today, but its performance still falls short of what’s needed to significantly move the industry forward.
Research has proven that gallium nitride (GaN) is far superior to its Si and SiC counterparts due to properties that allow for devices that are significantly smaller in size and weight, with no downgrade in performance. These systems are not only smaller and lighter, but much cheaper to produce.
Industry experts assert that GaN is the future of semiconductors, but there are technical challenges that have stunted its progression. While a handful of companies currently produce GaN enabled devices, processing challenges have limited their use to applications below 650V - acceptable for small electronics and lap top batteries, but not nearly enough to power a bus driving across the country.
So far, there are no viable GaN supported devices for high-voltage applications in the market, but the founders at Odyssey Semiconductor have patented a breakthrough process for building GaN devices that can power applications well beyond 650V. As the Odyssey team works to refine the process and produce the first engineering samples, Khurram Afridi, Associate Professor of Electrical and Computer Engineering, and his team at Cornell University have been busy researching potential applications based on the predicted performance of Odyssey’s GaN devices.
Most notable for the electric vehicle industry is the concept of “on-the-go” charging. Imagine a special lane on the highway that allows vehicles to recharge without even stopping. The massive infrastructure undertaking required means we won’t likely see driverless trucks making non-stop coast to coast trips in the near term, but it is an attainable future goal.
Once high-voltage GaN devices are available, there are many on-the-go charging applications that could be just around the corner. Companies with giant warehouses and distribution centers are already using robots for everything from cleaning the floors to stocking inventory, but even robots must take breaks to recharge. By charging on the go, a reduced fleet could accomplish the same or better results.
With the latest advancements in semiconductor and battery technology, cars and buses that charge while waiting for a traffic light to change could be a reality in a matter of years, not decades. The world of technology innovates at a blinding speed. While the semiconductor industry tends to reinvent itself at slightly less accelerated pace, the promise of GaN suggests that the next major transformation is just ahead, and it will usher in a world of possibilities we’ve only just begun to imagine.