Unigrid unveils sodium-ion residential energy storage systems

California-based battery developer Unigrid has launched its first residential energy storage system, Na+Casa, utilizing proprietary sodium-ion technology. The system aims to provide a safer and more durable alternative to conventional lithium-ion batteries, boasting a lifespan of over 27 years and a wide operational temperature range. This launch marks a significant step in the commercialization of sodium-ion chemistry for the residential market as the company begins initial installations in Europe.

Unigrid’s Na+Casa system is built around the company’s proprietary sodium chromium oxide (NaCrO₂ or NCO) cathode technology, which is designed to eliminate the fire risks typically associated with lithium-ion batteries. The battery module offers 9.25 kWh of usable energy and is rated for 10,000 full charge-discharge cycles at 100% depth of discharge, which equates to more than 27 years of daily use. Some of the company’s commercial-grade products are even rated for up to 30,000 cycles, highlighting the long-term durability of the NCO chemistry.

The hardware is designed for versatility, featuring a wall-mounted form factor with optional wheels and weighing 108.9 kg. Technically, the unit operates at a nominal voltage of 46.4 V with a standard charge and discharge current of 50 A, though it can support discharge pulses as high as 200 A. A key differentiator for the Na+Casa is its resilience to extreme weather; it can charge in temperatures as low as -20 C and discharge in environments reaching -40 C, while maintaining performance up to 60 C.

While initial installations have already commenced in Europe, Unigrid expects to bring the product to the United States market by the end of 2026. The system is designed to be cost-competitive with lithium-ion alternatives and compatible with most existing hybrid inverters to facilitate easy solar retrofits. To support this rollout, Unigrid aims to reach 1 GWh of annual battery cell production capacity by 2026 and is exploring third-party ownership models to lower the upfront cost barrier for homeowners.

The introduction of Na+Casa places Unigrid among a competitive field of sodium-ion developers, including Eleven Energy, Biwatt, and Lithium Valley. Unigrid is currently working toward completing CE marking and UL 9540 and UL 1973 certifications to solidify its market position. CEO Darren H. S. Tan emphasized that the technology’s long lifespan makes it an ideal asset for leasing models, which the company plans to pilot in commercial energy storage projects in California later this year.