For well over a century, the humble lead-acid battery has been one of the most familiar pieces of hardware under the hood, and one of the most common sources of frustration when a car refuses to wake up. Even modern electric vehicles still rely on a separate low-voltage battery to power computers, control modules, lights, infotainment systems and the electronics needed to bring the high-voltage propulsion system online. Now that long-standing arrangement is starting to change. Chinese battery manufacturer Xupai Power has become a supplier of sodium-ion low-voltage batteries for BAIC’s ARCFOX electric vehicles, marking an important step toward putting sodium-ion technology into regular passenger-car production as an alternative to the traditional 12-volt lead-acid battery.

The appeal is easy to understand. Sodium is abundant, relatively inexpensive and does not require some of the critical materials associated with conventional lithium-ion battery chemistries. Xupai says its automotive sodium-ion batteries can deliver strong cold-weather performance, substantial weight savings and significantly longer cycle life compared with traditional lead-acid designs. The company’s latest figures claim more than 5,000 deep-discharge cycles for its low-voltage technology, while its product range is being developed for 12V, 24V and 48V applications. That means sodium-ion is not limited to serving as an auxiliary battery in an EV. The same basic chemistry could eventually be used for conventional starter batteries, start-stop systems, mild hybrids and increasingly power-hungry low-voltage electrical architectures.

Weight could be another major advantage. Engineering work from IAV has demonstrated a 12-volt sodium-ion prototype with a minimum capacity of 70 Ah weighing about 9.9 kilograms, with the company estimating roughly 50 percent less weight than a comparable midrange lead-acid battery. That may not transform a vehicle’s efficiency on its own, but automakers spend enormous amounts of engineering effort removing kilograms wherever possible. Sodium-ion batteries also have the potential for excellent low-temperature operation, which matters because an auxiliary battery has to function reliably even when the main traction battery is sitting in bitter winter weather. Modern versions also incorporate their own battery-management electronics rather than behaving like the relatively simple lead-acid batteries drivers have known for generations.

Xupai and BAIC are far from alone in believing sodium has a future in cars. CATL has already taken the technology much further with its Naxtra sodium-ion traction battery, which the company says reaches energy density of up to 175 Wh/kg and retains more than 90 percent of its capacity at minus 40 degrees Celsius. Changan and CATL have also announced a mass-production passenger vehicle using sodium-ion propulsion batteries, showing that the chemistry is being pursued at both ends of the automotive electrical system. Meanwhile, Camel Group recently confirmed that one of its 12-volt sodium-ion batteries has entered a pre-development program with a major European automaker, and low-voltage battery giant Clarios is developing its own sodium-ion systems with partners including Altris, with plans for serial production before the end of the decade.

None of this means the lead-acid battery is about to disappear from dealership parts counters. Lead remains cheap, well understood and backed by an enormous manufacturing and recycling infrastructure built over generations. Sodium-ion still has to prove that its real-world durability, cost and packaging advantages hold up when production scales into the millions, and vehicle electrical systems may need to account for battery-management and charging requirements that differ from traditional lead-acid hardware. Still, the ARCFOX program is significant because it moves sodium-ion closer to being an actual factory-installed automotive component instead of an interesting laboratory alternative. After more than 100 years of lead-acid dominance, the little battery that starts or wakes up your car may finally be due for a serious technological rethink.