US battery lab finds new way to supercharge in 10 minutes
Researchers from PennState University (US) have developed a new design for lithium-ion batteries to safely supercharge it in 10 minutes or less and add an extra 300 kilometers to an electric car’s range.
The technique is to build in nickel foils that can heat the battery to 60°C in less than thirty seconds, avoiding lithium-plate deposits that deteriorate the battery rapidly otherwise. Their findings were described in the scientific journal Joule.
1.700 instead of 60 cycles
The team at the Battery and Energy Storage Technology (BEST) Center of the university found out that with the conventional method for fast charging at 20°C, the battery lasted for 60 cycles before the deteriorating effect of lithium-plating at the negative electrode occurred.
By inserting the nickel foils to preheat the battery rapidly to 60°C, the battery could be fast-charged from 1.700 to 2.500 times before the lithium-plating effect surfaces that limits the performance of the cell. That’s the equivalent of 14 years of use or 750.000 km of life, Chao-Yang Wang, co-director of the BEST Center, told the NewScientist.
Overturning old ideas
The scientists tested supercharging at 400 kW with temperatures of 40°C, 49°C, and 60°C, and compared with a control battery at 20°C. It showed performance was best between 49 and 60°C, and deteriorating won’t occur if the heating is limited to a short time.
It overturns the ‘old idea’ that batteries shouldn’t be charged at high temperatures, says Chao-Yang Wang. He and his team found out that the “benefits of a short burst of high temperature far outweigh the negatives.”
Preparing five-minute charging
According to the researchers, the technique is utterly scalable because it works with industrially available electrodes, and they already tested it in large battery packs. The nickel foil would add a 0,47% extra cost to the battery cells, but it would eliminate the need for external heaters in current models.
Chao-Yang Wang’s team is now planning to push the technique one step further and have a car battery charged in five minutes for the same range. But according to Wang, this “will require highly stable electrolytes and active materials in addition to the self-heating structure we have invented.”