Batteries might charge more quickly, but what are the power delivery issues?

The company is the latest in a string of organisations believing they can solve what, on the face of it, appears to be a significant challenge. A Singapore university claimed recently it could get batteries charged to 70% capacity in 2 minutes; earlier in 2014, the University of California unveiled a technology which it said will allow smartphones to be charged 'in minutes'. What these approaches seem to have in common is a new take on how the battery is constructed. StoreDot's technology is based on what it calls Nanodots – uniform crystals, each 2nm in diameter, formed from what the company says are bio organic peptide molecules. StoreDot says the crystals have the potential to be used in displays for smartphones and TVs, batteries, bio-LEDs and bio-lasers, with applications in nanomedicinal technology, drug delivery and food security labelling. Investors appear to be impressed; StoreDot has, apparently, received $48million in two funding rounds, including an investment from an as yet unnamed Asian mobile phone company. When used in batteries, StoreDot says Nanodots increase electrode capacitance, which reduces the charging time. It may well be that a Nanodot based battery can store charge more efficiently than those currently used in mobile phones, but the limiting factor – at least in my mind – is the battery charger. The story has been run by Reuters, which features a picture of a Samsung mobile phone indicating that its battery had been charged in less than 30s. Let's think about the power delivery issue. The battery in the Samsung Galaxy S5 has a capacity of 2800mAhr, which equates to 10368 Coulombs. If the battery is charged in 30s, then 10368/30 = 346A. The S5's battery is charged at 4.4V, so 4.4*346 = 1.5kW. That's going to need something slightly larger than the plug top devices we're currently using.