A long-lasting battery from startup Amprius is slowly making its way to your cell phone

An under-the-radar startup is moving ever closer to seeing its long-lasting lithium ion batteries power a growing number of cell phones and tablets. Amprius, which was launched in 2008 as a spin-out company from Stanford University, is already shipping its batteries to a small number of (undisclosed) Asian smartphone makers, and this week is announcing that it’s closed on a round of $30 million to continue commercializing those batteries.

The funding was led by Asian private equity firm SAIF Partners, and included the company’s current investors like Innovation Endeavors — the fund of Google Chairman Eric Schmidt — Kleiner Perkins, VantagePoint Capital Partners, Stanford University, and others. The series C round brings Amprius’ total funds raised to $61 million, making the company one of the more well-funded battery startups out there these days.

Innovation in Manufacturing: A123Systems, Amprius Score Funds from FedsSo what’s so great about this battery? The claim is that it can last around 25 percent longer between charges than the current lithium ion batteries on the market. That means that cell phone and tablet makers could use the battery to boast that their gadgets can be more mobile and unplugged for longer than their competitors’. As smart phones and tablets connect to faster wireless networks, and users download an increasing amount of power-hungry apps onto devices, extending the battery life of gadgets is becoming a major competitive edge for manufacturers.

A lithium-ion battery — the standard being used in gadgets today — is made up of three pieces: an anode, a cathode and an electrolyte that shuttles lithium-ions between the cathode and anode. That shuttling process is what happens when you charge and discharge a battery. Over time lithium-ion batteries degrade: they stop holding a charge as well and as long as when they were new, and have other performance issues.

Amprius’ battery tech, which is based on research from Stanford Professor Yi Cui,¬†uses a nano-structured silicon material for the anode part of the battery and that material allows the anode to be shrunk fourfold. As a result the anode can deliver a fourfold increase in battery energy density, which is the amount of energy that can be stored in a battery per given volume. Regular lithium-ion batteries can have an energy density around 400 watt hours per liter, while Amprius’ batteries have between 650 and 700 watt hours per liter, and the company is working on a 750 watt hours per liter battery in the lab.

In Amprius’ labs, it’s also developing other next-gen battery technologies beyond what it’s already built, like silicon nanowire anodes, sulfur-based cathodes, and advanced manufacturing processes. The company is using some of its new funds to advance these innovations.

Amprius headquartersBeyond cell phones and tablets, Amprius is now looking at ways to commercialize its batteries for electric cars, too. A longer lasting electric car battery could add 25 percent driving range for the current range-strapped EVs out there. Most electric cars on the market have a standard range between 100 miles and 200 miles. Tesla, which uses standard lithium-ion batteries for its battery packs, has a top range of 300 miles for its largest battery pack.

As the market for electric vehicles grows, the car makers will be eager to invest in better batteries that can give them a competitive advantage. Tesla thoroughly investigates all new batteries in its labs to see if there are available innovations beyond the commodity batteries it uses now, which are low cost enough and already provide it with the range it needs.

Battery innovation is notoriously difficult to deliver, both for startups and large battery companies. Just look to the case of Envia, a startup which tried to hit certain milestones to maintain a deal with GM for its electric cars, to see how hard the battery startup market is. It’s particularly hard for battery startups that are trying to hit milestones set by venture capitalists and business folks that are used to the quicker timelines of the internet and digital sectors.

Because battery innovation take a long time and costs a lot to commercialize, most of the innovation in lithium-ion batteries is likely to come out of the giant Asian manufacturers, instead of startups backed by Silicon Valley. If Amprius turns out to be the outlier that can buck this trend and its batteries perform as advertised, it could stumble onto a major market, or get snapped up by one of the Asian giants.