Credit: Creative Commons Lic.
One of the drawbacks of electric vehicles (EV) is that it can take up to 8 hours to fully charge their lithium-ion batteries.
Swiss researchers, however, say that by increasing the electrical charge, EVs can potentially be fully charged in about 15 minutes.
In a paper published yesterday, researchers from the Ecole Polytechnique Federale de Lausanne (EFPL) (Swiss Federal Institute of Technology in Lausanne) said an EV charging station with 4.5 megawatts (MV) of power could charge a vehicle in 15 minutes.
Unfortunately, 4.5MW is the power equivalent of 4,500 washing machines. "This would bring down the power grid," the researchers stated.
To overcome drawing such a significant charge from the power grid at one time, the researchers created a buffer storage system that disconnects from the grid before releasing the 4.5MW charge to an EV.
"We came up with a system of intermediate storage," said Alfred Rufer, a researcher in EPFL's Industrial Electronics Lab. "And this can be done using the low-voltage grid (used for residential electricity needs) or the medium-voltage grid (used for regional power distribution), which significantly reduces the required investment."
The EPFL researchers, along with other partner universities, built an intermediate storage battery. In the space of 15 minutes, it provided the 20 kilowatt hour (kWh) to 30 kWh needed to charge a standard electric car battery.
The "Intermediate" storage is achieved using a lithium iron battery the size of a shipping container, which is constantly charging at a low level of power from the grid. When a car needs a quick charge, the buffer battery promptly transfers the stored electricity to the vehicle.
"Our aim was to get under the psychological threshold of a half hour," Massimiliano Capezzali, deputy director of the EPFL Energy Center and leader of the research project, said in a statement. "But there is room for improvement."
A Tesla Supercharger station. Credit: Tesla
Supercharger stations are able to partially charge a Tesla Model S sedan in 30 minutes, giving it a 170-mile range. A full charge takes 75 minutes.
Superchargers consist of multiple Model S chargers working in parallel to deliver up to 120 kW of direct current (DC) power directly to the battery, according to Tesla.
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