Put together the best solar panels money can buy, super-efficient batteries and decades of car-making know-how and, theoretically, a vehicle might run forever. That’s the audacious motivation behind a project by Toyota Motor Corp., Sharp Corp. and New Energy and Industrial Technology Development Organization of Japan, or NEDO, to test a Prius that could revolutionize transportation.
Even if fully electric cars overtake petroleum-powered vehicles in sales, they still need to be plugged in, which means building a network of charging stations across the globe. The sun, on the other hand, shines everywhere for free, and when that energy is paired with enough battery capacity to propel automobiles at night, solar-powered cars could leapfrog all the new-energy technologies being developed, from plug-in hybrids to hydrogen fuel-cell vehicles,.
But the current forecast is only partly sunny because there’s still some work left to reach that level of efficiency.
“This is not a technology we are going to see widely used in the next decades,” said Takeshi Miyao, an auto analyst at consultancy Carnorama. “It’s going to take a long time.”
Not for lack of trying. Toyota and Hyundai Motor Co. already introduced commercial models with solar panels on the roof, but they were too underpowered and could barely juice the sound system.
“The solar car’s advantage is that — while it can’t drive for a long range — it’s really independent of charging facilities,” said Koji Makino, a project manager at Toyota.
Indeed, there have been some breakthroughs, mainly due to advancements by Sharp. The prototype’s solar panel converts sunlight at an efficiency level of more than 34%, compared with about 20% for current panels on the market.
Because the solar cell being used by Toyota, Sharp and NEDO is only about 0.03 mm thick, it can be placed on more surfaces, including the curvy parts of the roof, hood and hatchback. The electrical system can charge the vehicle even when it’s on the move.
If the car is driven four days a week for a maximum of 50 kilometers a day, there’s no need to plug into an outlet, NEDO’s Yamazaki said.