[Corrected, 9:35 pm.] Ask an engineer why we power our cars with gasoline rather than electric batteries and you’ll get a geeky answer: energy density. Said another way, gasoline holds far more energy in a given space than any battery ever has.
Ann Arbor, MI-based Sakti3 yesterday published test results that show its battery has double the energy density of today’s lithium ion batteries used in consumer electronics and many electric vehicles. Practically speaking, that means a Tesla Model S electric sedan could have almost double the driving range and a smart watch could run for nine hours on a charge, rather than three and a half.
On a technical level, it’s an impressive result. But it’s worth remembering that many battery technologies have fallen far short from the hype. One company called Envia Systems, which, like Sakti3 received funding from GM Ventures, claimed a breakthrough in energy density for lithium-ion batteries but failed to deliver the promised performance when planned, according to reports. [The original article misstated Envia Systems’ status as a business.]
Still, there are reasons to believe that Sakti3—which plans to have its batteries in consumer electronics in only two years—has got something real. The first reason is its technology. A conventional lithium-ion battery has two electrodes and a liquid electrolyte through which charged atoms flow between the positive and negative electrodes during charging and discharging. The design requires supporting materials, such as separators, and cooling systems that don’t actually store energy.
Sakti3 is making a solid-state lithium battery, which is made out of three solid layers—anode, cathode, and electrolyte—an approach that saves space and weight. These batteries promise to be cheaper than today’s lithium-ion batteries and are considered safe, whereas electrolytes are often flammable. The company has been making prototypes on modified vapor deposition equipment used in industries, such as solar and flat panel displays.
The solid-state technology gives it an advantage because all the incumbent lithium-ion battery makers use effectively the same manufacturing equipment, says CEO, founder, and Xconomist Ann Marie Sastry. “Our approach uses a completely different manufacturing platform, which we strongly believed was necessary to make the big leap in energy density,” she says.
Also, the company’s business strategy has been designed to get a product out quickly and without burning through huge amounts of capital—a peril in the world of hardware manufacturing. It’s relied heavily on mathematical simulations in designing its cells and it could make its first product through a contract manufacturing partnership, Sastry says. It’s also built prototypes on equipment that can scale up to high volumes, important for keeping costs low.
“The whole point was to develop batteries based on something that already exists because we didn’t want to invent a battery cell, a manufacturing process, and equipment. That takes a long time and there’s an enormous amount of technical risk,” she says. The six-year-old company raised a bit more than $30 million to date.
Satki3’s progress is a rare glimmer of good news among companies developing advanced batteries for consumer electronics or electric vehicles. There are a number of startups building new types of batteries for grid storage, but lithium-ion batteries are expected to dominate the auto and electronics industry for years. There are a handful of other companies also developing solid-state batteries, including Toyota as well as startups Seeo in Hayward, CA, and Solid Power Battery, a spinout from the University of Colorado Boulder. Another solid-state battery hopeful called Planar Energy appears to have shut down.
Cost-wise, Sastry thinks the company can deliver batteries at about $100 per kilowatt-hour, substantially less than half the current cost of lithium-ion batteries used in electric vehicles. At this point, the company has no concrete plans in the auto industry but when it comes to consumer electronics, “we see a very clear path to make these battery cells.”
