A safer next-gen battery is used with solar panels for the first time

The unnerving capability of lithium ion batteries to catch on fire emerged as headline news last month, as Boeing was forced to ground its futuristic 787 Dreamliner FLEET after two batteries caught on fire. But the next generation of lithium ion batteries are promising to be safer, and a few of them are already starting to be used in real-world situations in the power grid, electric vehicles and gadgets.
Six-year-old startup Seeo — which is backed by Vinod Khosla, Google.org and others — has installed its first battery system to act as energy storage in conjunction with a solar panel system developed by SunEdison, according to Seeo CEO Hal Zarem, who I interviewed last week. The solar battery installation is a trial for now, but a sizable one: on the level of kilowatts and tens of kilowatts, explained Zarem. For comparison’s sake, the Nissan LEAF uses a 24 kilowatt hour battery, while an average cell phone will use 2,000 to 3,000 milliamp hour batteries (far smaller than a kilowatt hour of capacity).
SeeoBatteries, like the one Seeo has installed for SunEdison’s solar system, can act as storage for the energy produced by solar panels, so that when the sun goes down (or behind a cloud) the battery can then offer up the stored power. Utilities, building owners and even home owners are starting to see the benefits of having battery storage systems connected to solar systems, because power can be far more smooth and reliable. Likewise solar installer SolarCity (s SCTY) has been working with Tesla’s (s TSLA) batteries to sell a home battery system with its solar panels in certain markets.
The next-gen tech
So what makes Seeo’s batteries safer? It largely involves improvements to the electrolyte, or the medium that shuttles lithium ions back and forth between the cathode and the anode to charge and discharge the battery. Traditional lithium-ion battery electrolytes are mostly made of liquids, while Seeo is using a solid dry polymer based electrolyte, which feels like plastic to the touch.
The polymer is non-flammable and when combined with using lithium foil as the anode, the battery can be ultra light weight and also have a high energy density, or amount of energy that can be stored per a given weight. During an interview at Seeo’s headquarters last week I picked up and compared two battery packs — one made by Seeo, and one that used traditional lithium ion batteries — and the Seeo battery felt about three times lighter.
If traditional lithium ion batteries are overcharged they can have a margin of error in the danger zone of about 20 percent above the max voltage of the battery, explained Zarem. In contrast, Seeo batteries have a margin of error of 100 percent over the voltage. The batteries also won’t burst into flames if something penetrates it (for example, during a car crash).
Seeo isn’t the only one working on solid electrolytes for batteries. It’s actually a growing field for innovation, and startups like Sakti3, and Imprint Energy are working on this technology, as are researchers at Oak Ridge National Laboratory.

What’s next
Seeo has just started commercializing its technology and working with customers to test out its batteries. The company has built out a pilot production line at its headquarters in Hayward, Calif., which can make 4 MW hours worth of batteries using traditional manufacturing machines like coaters. I toured the company’s pilot line last week and the team is indeed heads down churning out small levels of Seeo batteries.
SeeoBut to get to the next-level of manufacturing, which involves hundreds of megawatt hours — the kind that could start to actually change the game for solar energy storage, or electric vehicles — Seeo plans to build a new factory somewhere in the U.S. this year, close enough to the Hayward site to create easy collaboration. It could end up being built in Hayward, says Zarem, but the company is still in the process of figuring out the best location.
Seeo could have to raise some sort of funding to get such a plant built, and probably has already started raising such funding. But on that funding note Zarem wouldn’t comment. Raising funding could be difficult in 2013, after so many advanced battery companies, like A123 Systems, struggled in 2012. Eventually Seeo also wants to build an even larger plant, but that would likely be developed outside of the U.S., in a low cost manufacturing part of the world, said Zarem.
Along with Google.org, and Khosla Ventures, Seeo also has investors Chinese firm GSR Ventures, and Presidio Ventures, a fund managed by Japanese giant Sumitomo. So clearly, Seeo has some strategic connections in overseas markets.
Seeo’s Zarem has an interesting perspective on the past couple of years of battery innovation. A generation of large battery factories were built out in recent years, he said, some using U.S. government funds to meet an anticipated market for electric cars (like A123 Systems). Unfortunately that electric car market didn’t emerge as quickly as expected, but it’s coming, as is energy storage for clean power.
Sometimes the companies that are the first to market either aren’t the right ones, or they’re too early, says Zarem. Of course, he’s hoping that Seeo has timed it just right.
This article was updated at 10:15AM to correct that the company has an investment from Google.org, instead of Google Ventures.