As electric vehicles go mainstream, the auto industry has largely reached the consensus that the next big thing is no longer about eliminating gas engines, but finding the most efficient method to generate electricity to power cars. Some companies, including Tesla, focus on perfecting the already popular lithium-ion batteries; others take the risk to explore new battery tech such as hydrogen fuel cells and solid-state batteries.
But few have pursued an alternative energy source that dominates elsewhere: solar power.
What’s stopping EV companies from making a car wrapped in solar panels that can automatically charge itself up when it’s sunny outside and then have enough juice to hit the road the next morning? The concept sounds simple enough and perfectly environmentally friendly.
In fact, there were some early attempts at harnessing the sun’s energy for automobiles. In 1955, a General Motors engineer built a tiny, 15-inch-long solar car, dubbed the Sunmobile, to show the possibilities of solar energy. Unfortunately, they were unable to build out the prototype into a fully solar-powered car due to limitations in energy efficiency, storage and (obviously) weather. And since, engineers have come to the conclusion that no solar panel can generate enough power to support a car’s regular use while being small enough to be carried around by a car.
But Laurin Hahn, the founder and CEO of German startup Sono Motors, believes that the idea is still worth exploring. His approach is intuitive: using solar at maximum by wrapping an entire car in solar cells.
“People will always say it’s a gimmick. But it’s not. Solar brings down costs and makes EV more affordable without sacrificing the convenience,” Hahn told Observer in an interview last month.
At this year’s (virtual) Consumer Electronics Show in January, Sono unveiled its latest prototype SEV (solar electric vehicle), a passenger car called Sion. The company also showcased a trailer outfitted with Sono’s solar body panels to demonstrate the technology’s potential to be integrated into other vehicles.
At first glance, Sion doesn’t look much different than any other black compact car roaming the streets in European cities. But upon closer inspection, it becomes clear that the car’s exterior is made up of hundreds of solar cells molded into polymer. These solar cells (which total 248 in all) convert sunlight into energy, which is then stored in the vehicle’s battery. Based on average weather in Munich, solar cells on a Sion can generate up to 1.2 kilowatts a day, which translates into 21 miles of driving range. That alone is enough for most commuters in Europe, who on average drive 11 miles a day.
In America, people drive a bit more (average 30 miles a day), but also likely live in places that have more sunny days than Munich.
Yet, it’s still not quite a fully solar-power car. Combined with its built-in lithium-ion battery, a Sion can last for 155 miles on a single charge at a maximum speed of 140 km/h (87 mph).
But Sono’s solar panels aren’t designed to replace traditional charging methods anyway, Hahn stressed. Instead, it’s supposed to be a power supplement to reduce a battery car’s reliance on charging infrastructure. In Germany, for instance, where commuters drive 10 miles daily, solar integration in the Sion car extends the need to plug in from once a week to once a month.
The larger purpose is to integrate the technology into the rest of the transportation industry. “We have a two-fold goal: to build an affordable mass-market SEV and to make this technology available to other battery-powered vehicles, trains, boats, basically any moving thing that consumes electricity,” Hahn explained.
“We have huge demand from refrigerated trucks, for example,” added Thomas Hausch, Sono’s chief operating officer. “The trailer industry has huge pressure to move toward zero-emission. And we have found a solution for them that’s viable and affordable.”
In January, Sono struck a deal to license its solar technology to EasyMile, a French company making electric autonomous shuttle buses. Not disclosing names, Hahn said the company is in talks with several mobility companies “that have a lot of vehicles on the road,” and “they are highly interested.”
Correction: A previous version of this article inaccurately stated that Sono is in talks with U.S. automakers for licensing deals.