If there’s one thing that is holding batteries back, it’s cost.
The most typical sort of battery, lithium-ion, still costs about $140 per kilowatt hour per pack. While this is sufficiently small to drive rapid adoption of electrical vehicles, even the least expensive lithium-ion chemicals are still too expensive to install large batteries in every home to protect against blackouts.
Instead, manufacturers have begun exploring sodium-ion batteries not as a substitute, but as a complement to lithium-ion batteries.
“If produced at the same scale, the sodium ion should be about half the cost of producing lithium iron phosphate because the raw materials are a hundred times cheaper” – Darren Tan, co-founder and CEO of the company Unigridhe told TechCrunch.
Despite its guarantees, sodium ion is not yet ready for widespread use. Batteries fabricated from it are not very dense, which makes them too large and too heavy for electric vehicles. Additionally, many variants behave in a different way from lithium-ion batteries when charging and discharging, which implies that packs made using sodium ions require recent electronics to manage them.
Tan’s startup believes it has solved these problems by using a recent chemical based on sodium oxide and chromium in one half of the battery and tin in the other (though Tan emphasizes that the company can substitute other materials on either side). Unigrid batteries take up no extra space than lithium iron phosphate cells, sometimes less. Additionally, their power output mimics that of lithium-ion, so the company can use the same electronics, and they are made from commonly available materials. “Twice as much copper is produced each year as chromium,” Tan said.
The company was born out of Tan’s research at the University of California, San Diego, where he was a graduate student under Shirley Meng, a prolific materials scientist specializing in energy storage. Their goal was not only to create a cheaper battery, but also one that was safer.
Unigrid batteries is not going to overheat and catch fire until the internal temperature rises to several hundred degrees Celsius, Tan said. “Sodium-ion should not be like lithium-ion, it should be much safer, so that it can be put in buildings, hospitals, data centers, so that we can achieve widespread distributed energy storage,” he said.
To supply so many batteries, Unigrid is not going to build its own factories. Instead, it’ll work with smaller battery makers that exist simply to create third-party designs. Think of them like TSMC, which makes computer chips for firms like Apple and Nvidia, albeit on a much smaller scale. Unigrid’s chemistry division runs on existing equipment, and Tan said there is enough spare capability at these plants to produce batteries on a megawatt-hour scale.
Unigrid’s first market can be energy storage for buildings and small campuses, but it also wants to supply makers of so-called light electric vehicles akin to scooters, motorcycles and tuk-tuks. These forms of small vehicles are popular in India and Southeast Asia, where intense heat can make lithium-ion batteries prone to overheating. “There are huge opportunities where the climate is very warm and there are a lot of battery fires,” Tan said.
To start producing sodium-ion batteries, Unigrid raised $12 million in Series A funding. The round was led by Transition VC and Ritz Venture Capital, with participation from Union Square Ventures and Foothill Ventures.
Tan hopes that Unigrid will start selling cells sooner or later. “We really wanted to do something that could have a more immediate and shorter-term impact, something we could bring to market in the next five years,” he said.