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
Tell me if I made any error in the above...
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)
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.
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.
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!!