Bill Gates backs storage innovator

US energy storage technologist Aquion Energy has landed $35m in new funding from investors including Microsoft founder Bill Gates to push its “environmentally benign” aqueous hybrid ion (AHI) battery to commercial roll-out.

The financing round was led by Bright Capital with money from Gates, Gentry Venture Partners, Kleiner Perkins Caufield & Byers, Foundation Capital, and Advanced Technology Ventures.

Aquion says it will be delivering initial, pre-production AHI units to “selected lead customers and partners” throughout 2013.

That will be followed by the shipping of first commercial batteries from its high-volume manufacturing plant in Pittsburgh, Pennsylvania to “enable broad adoption of renewable energy technologies”.

The AHI battery system – based around a saltwater electrolyte, sodium ions, an activated carbon anode and manganese-oxide cathode, and cotton separator – is designed to be scaled from off- and micro-grid systems up to industrial energy storage, and grid-network applications.

Tests of prototype coin cells that followed the Sandia Nation Lab “partial state of charge” rapid cycling protocol showed a less than 10% capacity fade after more than 5,000 cycles at over 50% depth of discharge – a measure of a battery's state of charge.

Aquion’s AHI battery does not use corrosive reactions to store electrical energy, as is common for other battery chemistries such as lead-acid, meaning they do not need to be immediately charged once they have been discharged, and can held at a partial state of charge for “very long periods of time” without damage.

The batteries, which are non-toxic and contain no heavy metals, are also said to be “extremely fault tolerant” and can be short-circuited without causing an explosion or fire.

“Aquion has demonstrated the viability and potential disruptiveness of its novel energy storage technology. We expect Aquion’s products to be a key enabler for the emerging energy-storage industry that many experts predict will grow exponentially in the next decade,” says Bright Capital managing director Mikhail Chuchkevich.

Aquion chief executive Scott Pearson adds: “This group will provide critical operational and financial support to the company [in] launching our initial storage products and beginning to ramp the business in 2014 and beyond.”