The fast charging comes from the nanotechnology developed by StoreDot for lithium ion batteries, which trades off some energy density and cycle lifetime.
“Our vision is five minutes – five minutes full charging of any electric vehicle,” said Doron Myersdorf CEO of StoreDot. “We have demonstrated a two wheeler and we are working on a four wheeler.”
StoreDot was founded 8 years ago in Israel and has raised $130m. Strategic partners include TDK for cell manufacturing, car and truck maker Daimler, Samsung for consumer equipment including mobile phones and BP for charging infrastructure.
The company has 57 patents granted and 48 in process on nanotech metalliods of tin, silicon and germanium, all known to have high diffusion and low resistance for lithium ions used in the cell. “The challenge is to replace the materials in the battery particularly the graphite, which limits the fast charging and to do that we need to rethink the materials,” said Myersdorf.
Storedot also develops organic compounds as 3D binders, protecting silicon with a polymer style material that will give it the flexibility to absorb the ions but make sure there are no cracks or impurities as it inflates and deflates during charging. Some of the binders are self healing so if there are cracks they heal over time.
The demonstration uses the first generation cells that are now starting to sample.
“At the end of 2018 we signed a manufacturing partnership with EVE Energy in Shenzen and we are working very closely with them to release Gen 1 which is ready for sampling and most likely they will produce Gen 2 among other partners,” said Myersdorf.
Next: Fast charging battery test
Testing is key to the technology development. “Our data scientists correlate the vast amount of data,” he said. “We have thousands of cells in development and each of those produces a lot of data every minute to the cloud so we are using AI and machine learning to see which formulation perform best.”
“Most of our competitors are focussed on increasing the energy density – we are different, we are focussed in the ultra fast charging as the number one parameter. We are compromising 10 to 20 percent in energy density but this opens up a whole new set of opportunities with the ultra fast charging,” he said,
The drone system charges with a constant current (CC) charger at 135A to give a 6.8Ah battery pack a 30 minute mission time with minimal changes to the 4.5kW charger or the drone battery management system. In contrast, an electric car fast charger operates at 200 to 500A.
There is also a tradeoff in battery life. “We can charge in one minute – the technology charges in one minute but you pay in the number of cycles, 150 cycles for 5 minutes, perhaps 30 cycles for one min. This technology can really take all the power in a short amount of time,” he said during the demonstration.
A thousand first generation cells have been produced with 100 to 160 cycle lifetime and a temperature range of -20 to +60 degC and the cost is likely to be two to three times that of current graphite lithium ion cells. “In 18 months we will sample gen 2 in small form factor with slightly higher energy and much better cycle life,” said Myersdorf.
Qualcomm has launched its latest fast charging technology for Andorid phones that can charge a mainstream ltihium ion mobile phone battery to 50 percent in five minutes, again using constant current, but requiring longer for the rest of the battery using constant voltage: QUALCOMM LAUNCHES 100W QUICK CHARGE 5
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