California-based sodium-ion battery company Unigrid has announced the launch of Na+Casa, its first-generation residential energy storage system (RESS) and says it has completed the first installations of the system in homes across Europe.
The Na+Casa systems contain battery cells made with the company’s proprietary sodium chromium oxide (NaCrO2 – often abbreviated NCO) cathode technology, which Unigrid says gives the batteries an extremely long usable lifespan and zero fire risk, compared to traditional lithium ion battery cells.
Unigrid says the Na+Casa battery has an operational lifespan of 10,000 charge-discharge cycles of 100% of its capacity — equal to daily cycling for more than 27 years. Some of the company’s commercial products promise lifespans of greater than 30,000 cycles.
In addition to the longevity benefits, the company touts the battery’s ability to charge at temperatures between -4° and 140° F (-20° to 60° C) and discharge at temperatures between -40° and 140° F (-40° to 60° C).
“As residential energy bills rise — especially during extreme weather events such as the record heatwave we are seeing around the world — homeowners need storage that is safe, reliable, and financially sound,” said Unigrid CEO Darren H. S. Tan in a statement. “With Na+Casa, UNIGRID is moving NCO sodium-ion from just a promising technology to a tangible residential storage product, giving installers and integrators a lucrative alternative to lithium-ion.”
Weighing 240 lbs (108.9 kg) and measuring 18.78 inches (477 mm) wide, 34.12 inches (869 mm) tall and 10.6 inches (269 mm) deep, the Na+Casa battery can be mounted on a wall or installed with optional wheels. Each battery can store 9.25 kWh of usable electricity, with a nominal voltage of 46.4V and a standard charge and discharge amperage of 50A (discharge surging up to a 200A pulse).
The Unigrid batteries currently have UN 38.3 certification, and the company expects to have CE listing and UL 9540 and UL1973 certifications completed soon.
Unigrid said the battery is compatible with most existing hybrid inverters and was designed to simplify residential solar retrofits and be price-competitive with lithium-ion solutions today. The company expects to launch the Na+Casa battery in the U.S. by the end of 2026.
The Na+Casa battery is part of a nascent group of sodium-ion batteries coming to certain markets around the world. Other entrants include a recent modular residential offerings from Eleven Energy, Biwatt and Lithium Valley, the final two of which have obtained the UL certifications necessary for sales to the U.S. market.
Unigrid has said it plans to reach a milestone of 1 GWh of battery cell production in 2026, and Tan has argued that the 25-year lifespan of the batteries will make them ideal for long-term third party ownership under a leasing model.
Unigrid is preparing to test that model in commercial energy storage deployments in California later this year, and the company’s new residential offering is set to take its place alongside the larger commercial batteries.
“It’s going to be a long-term asset, and by offering it at zero money down, we can reap monthly benefits together with the user rather than forcing them to fork out a large amount of cash on day one hoping that this thing will last 25 years,” said Tan, in comments to pv magazine USA in May, 2026. “We take the risk away from them.”
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