LAS VEGAS — In the future, you’ll be able to recharge your electric car for free — using only the sun.
That’s Ford’s vision, at least. At the Consumer Electronics Show here, Ford is showing off a prototype of a solar-powered plug-in hybrid. The company has designed a system that will allow the car to use the sun to fully recharge its batteries in eight hours, given the amount of sunlight seen in a typical American city.
The car is basically a standard C-Max Energi plug-in onto which the company has affixed some of SunPower’s highest-efficiency solar panels, the X21s. They work in tandem with the car’s own sensors and a specially designed canopy that helps direct sunlight to the panels.
While the SunPower panels are among the most efficient on the market, they only convert about 21 percent of sun energy into electricity. As such, they aren’t enough to fully recharge the C-Max’s 8 kWh during the day. In fact, over the course of eight hours, the panels on the C-Max would only be able to replenish about 1kWh of energy, said Ford’s Mike Tinskey, Ford’s global director of vehicle electrification and infrastructure.
So, the company has designed an aluminum canopy to hold acrylic magnifying lenses that would concentrate sunlight onto the solar panels. The lenses would essentially increase the amount of sunlight hitting the panels eight times, allowing them to fully recharge the car’s battery in eight hours.
Well, they would, if the sun stayed stationary in the sky for that full time. But it doesn’t, of course. So Ford’s solar recharging system envisions using the car’s sensors and capability for autonomous movements to continually, but gradually, reposition the car during the day so the optimum amount of sunlight is hitting the solar panels. The car would move in 1-inch increments, moving about 7 feet during the course of the day to follow the sun.
For now, the system is simply a prototype. Ford hasn’t committed to building the car or the canopy. And the company is wrestling with how to address serious questions concerning its feasibility, Tinskey said.
In particular, the company needs to show that the system will be robust enough to handle potentially dangerous weather events, such as hailstorms. The company also needs to figure out how to protect people from being harmed by the solar concentrator. And it’s still working on the business model.
Showing that the system is robust shouldn’t be difficult, Tinskey said; the solar panels are the same as those that are already mounted on the roofs of homes, so they’re already built to withstand things like hail. And Ford has some ideas on how to protect people from the solar rays. One possible solution would be a system that would electrically change the transparency of the lens when the canopy detected people or animals nearby.
In terms of the business case, the canopy is designed to be relatively low cost, and, by providing free power, could potentially save consumers significant money on their electrical bills, argued Tinskey. It also could make a lot of sense in areas of the world whose electrical grids are underdeveloped or as a greenhouse gas-saving measure in areas that generate electricity from carbon-spewing coal. And, the system could prove a relatively low-cost alternative for companies exploring options for allowing their employees to recharge their electric cars.
But he acknowledged that the system won’t be practical for all consumers. They’ll have to have a sufficient space for their cars to move and track the sun. And the car will have to be able to move in an east-to-west direction.
Those and other to-be-resolved issues are “why we’re calling this a concept,” Tinskey said. He added, “We want to start the discussion.”
Photo, of Ford’s solar-powered concept vehicle and canopy, by Troy Wolverton