Chinese battery maker Xupai plans to supply sodium-ion low-voltage auxiliary batteries for BAIC Arcfox electric vehicles starting in 2027, targeting at least 200,000 units initially, according to its CEO Desmond Zhang, as reported by Automotive News Europe and Chinese outlet D1EV.
The deal marks a pragmatic entry for sodium-ion technology into the automotive sector, not as a traction battery but as a low-voltage auxiliary power source. Unlike the high-energy-density demands of driving batteries, this application prioritizes power output, temperature tolerance, longevity, safety, and cost—areas where sodium-ion cells can compete effectively.
In battery-electric vehicles (BEVs), a separate 12-volt battery handles initial wake-up functions like unlocking, interior lighting, and seat adjustment before the high-voltage system engages. It also powers the contactors that connect the main battery, meaning a depleted auxiliary battery can leave the vehicle undrivable even with a full traction pack. During operation, the auxiliary battery works with a DC-DC converter to buffer transient loads and provide backup power if the high-voltage system fails.
Xupai claims its sodium-ion cells operate between -20°C and 80°C without active thermal management, a wider range than typical lithium-ion batteries, which may degrade around 40°C and charge poorly below -20°C. These figures are company estimates and require validation in real-world vehicle testing. The International Energy Agency (IEA) has noted potential low-temperature advantages for next-generation sodium-ion batteries, though challenges remain in energy density, supply chain maturity, and cost.
Cost and market potential
Cost is another factor. Zhang estimates high-rate lithium-ion cells for automotive low-voltage systems cost $0.12–0.20 per watt-hour, while sodium-ion cells are around $0.10, offering a cell-level advantage. Energy storage lithium cells can be cheaper at $0.06, but their power characteristics do not meet low-voltage system requirements. These are company estimates, and sodium-ion's edge depends on raw material prices, yield rates, and scale.
The low-voltage battery's role is expanding with software-defined vehicles. Smart cockpits, advanced driver assistance systems (ADAS), and frequent OTA updates create pulsed power demands, making the auxiliary battery a foundation of the electrical architecture rather than a simple starter. Market Research estimates the global automotive low-voltage drive market will grow from about $2.1 billion last year to $2.7 billion by 2032.
German engineering firm IAV predicts sodium-ion could capture about 90% of automotive low-voltage applications within a decade, driven by software-defined vehicles. This is a forward-looking forecast that depends on cost, lifespan, and successful vehicle validation. The 48-volt architecture is seen as a next step, where sodium-ion could extend beyond 12-volt replacement into higher-voltage systems.
Still, mass adoption is far off. IDTechEx notes sodium-ion research spans decades, with only recent progress achieving automotive-grade cycle life and power density. Early products suffered capacity fade and cost disadvantages against lead-acid. Sodium-ion must still prove batch consistency, calendar life, crash safety, and lifecycle costs while competing with established lead-acid and falling lithium prices.
The Xupai-BAIC Arcfox partnership offers a pragmatic path: entering through low-voltage systems where power, temperature tolerance, and cost matter more than energy density. For sodium-ion, the first step into vehicles may not be driving the wheels, but waking up the car.
