Energy

Tiny solar cells could soon charge electric vehicles while on the road

Tiny solar cells could soon ch...
Perovskite solar cells, which are much smaller than traditional panels, could soon revolutionize electric vehicle charging
Perovskite solar cells, which are much smaller than traditional panels, could soon revolutionize electric vehicle charging
View 1 Image
Perovskite solar cells, which are much smaller than traditional panels, could soon revolutionize electric vehicle charging
1/1
Perovskite solar cells, which are much smaller than traditional panels, could soon revolutionize electric vehicle charging

Researchers claim to have hit on the right combination of solar cell type and battery to charge an electric vehicle battery with higher efficiency than ever before. The team behind the research says the system could soon make it possible to attach small cells to a car that will charge the vehicle while being driven – on a sunny day, at least.

The researchers from Case Western Reserve University wired four perovskite solar cells in series to directly photo-charge lithium batteries with 7.8 percent efficiency, which they believe to be the most efficient configuration reported to date.

"We found the right match between the solar cell and battery... Others have used polymer solar cells to charge lithium batteries, but not with this efficiency," said Liming Dai, the leader of the research team, adding that the coupling appears to have outperformed all other reported pairings of photo-charging components and compatible batteries or super-capacitors.

Perovskite has been one of the most promising solar cell technologies to emerge of late, thanks to its ability to convert a broader spectrum of sunlight to electricity when compared to silicon-based cells. The crystalline material has a structure identical to the mineral of the same name, and its potential for highly efficient power conversion and a quick payback in terms of energy savings over traditional power sources have made it one of the fastest growing sectors in the solar power field. As a sort of added bonus, it has even been found to emit light at night, functioning similar to an LED.

Dai's lab created cells with three layers converted into a single perovskite film and then wired four of the 1 mm square cells in series, achieving a solar-to-electric power conversion efficiency of 12.65 percent.

When hooked up to charge small coin-sized lithium-ion batteries, the team achieved a conversion and storage efficiency of 7.8 percent and maintained it over a number of cycles.

"We envision, in the not too distant future, this is a system that you could have at home to refuel your car and, eventually, because perovskite solar cells can be made as a flexible film, they would be on the car itself," said contributing author Jiantie Xu.

This would seem to make the technology a perfect fit for cars with a more traditional look than the Immortus solar sports car, whose every available sky-facing surface is covered in 7 sq m (75 sq ft) of solar photovoltaic paneling.

The research was published in the most recent issue of Nature Communications.

Source: Case Western Reserve University

19 comments
PeterMortensene7877c8e180f4d2a
Lots of problems for this technology: 1. The power generated will be quite little with only the top of the car being effectively catching the sun's energy. Thus this is a charging solution and not a solution for when you are driving. 2. Even if we assume those 7 square meters some day can produce 1kW similar to what good solar panels do today in a bright sun, it means you get about 3 miles of driving for 1 hour of being in the sun. That's effectively a speed of 3 miles per hour if you just used the sun to drive. 3. The sun is not providing a constant amount of energy and for this reason the battery size still need to support same range. You can't plan your life to drive only on sunny days, can you? Thus there is no real argument of saving cost with a smaller battery and use them for these solar cells. Rather the car will overall be more expensive. 4. A car covered in expensive solar cells will be a nightmare to repair in case of an accident. Also these expensive parts with expensive repair process will make your insurance skyrocket. 5. Forget about getting the car in the color you want. This more expensive car will not leave much options for tailored colors. 6. 7 square meters of solar cells will add some weight of the car. Tell me if I made any error in the above...
Alien
So...will cars of the future have roofs that glow at night?
Martin Winlow
Typical EV uses ~20kW (thats 20 THOUSAND watts) at 60mph. 7.8% efficient charging x ~1kW electrical energy/m2 FULL sunshine x 2m2 sky-facing car area = 160W (enough for all the lights and wipers... maybe)
Larry Butler
Horsefeathers. It takes 50-100 KILOWATT HOURS of power to charge an EV. There are only so many watts/square meter of solar power and 12% of that isn't going to recharge what the brake lights use in the 10AM-2PM solar charging day.
RelayerM31
Even if it only provides a fraction of what the car needs it's a step in the right direction. Add a solar powered home power station and you're set.
JPWhite
A more efficient solar cell has general purpose use right? Not just for an EV. While the 7.8% power conversion stated maybe a record, there are no details on how much power in total was delivered to the car batteries. I can drive 4.3 miles on 1 kWh. It would be much more useful to say how much power they generated on average per day during testing rather than quote efficiency percentages.
S Michael
Stop talking and show us some proof of concept, today, not five years from now.
Tom Lee Mullins
I think this would be a big boost for electric vehicles.
Michael Crumpton
So lets take a look at the idea of putting panels on a car vs on your house. Most cars have close to 4sq meters or less of useful area for cells. Each sq meter can receive a maximum of 1000 watts in full direct sun. Lets say generously the cells can gather 20% of that energy, you have a total of 80 watts/sq meter or 320 watts total. That is fine if you want to power a scooter, but you would have to charge for several days to get a full charge in a car. Now, if you put the panels on your house or a stand, you can put as many panels as you have room (and money for), in the perfect position for maximum output and you can put that power directly into the grid (and take it out later when you get home to charge your car). You can't actually power the car from the solar panels, so it just adds more cost and complexity to the car for very little value. You would constantly be avoiding shady spots to park, and avoiding parking garages.
Siv
I just want to know why we are messing about with electricity and batteries which cause much more pollution in their transport and manufacture, when we could just modify our existing gas cars to run on hydrogen! They could even make a good noise like a petrol car so that a) I like driving it and b) the pedestrians can hear me coming. Even the existing petrol station networks could be converted to accommodate hydrogen filling pumps and that would avoid load of job losses in that sector. I appreciate that hydrogen currently is manufactured using electricity but pretty much every week in Gizmag there is some scientist showing off how to produce Hydrogen from a desalination plant or using bacteria from existing waste! I say forget batteries and sort Hydrogen power!!