Sodium battery enters series production at Arcfox as 12-volt battery

An electric car has a small energy-storage unit that does not drive the wheels: It powers the electrical system, control units, infotainment and driver assistance. In electric vehicles from BAIC’s Arcfox brand, this task is now handled by a sodium-ion battery from Xupai. The manufacturer is thus bringing a replacement for the conventional 12-volt lead-acid battery into series production for passenger cars for the first time.

The technical difference is most apparent in service life and weight. For its 12-volt auxiliary battery, Xupai specifies more than 3000 cycles at 100 percent depth of discharge. Conventional AGM or EFB lead-acid batteries, which are common in Europe, typically achieve 200 to 400 cycles at a high depth of discharge, according to the cited data. Xupai’s starter variants are expected to deliver 500 to 900 amperes and be around 55 percent lighter than comparable lead-acid batteries.

The battery is not simply a different cell chemistry. A BMS, or battery management system, monitors voltage and temperature and can shut down in a controlled manner in the event of a short circuit. The batteries communicate via CAN or CAN-FD, common data connections in vehicles, and are intended to work as plug-and-play replacements in standard sizes without modifications to the vehicle’s electrical system. Compared with lead-acid batteries, sulfuric acid, corrosion and explosive-gas formation in the event of overcharging are eliminated; compared with lithium-NMC and NCA cells, the tendency toward thermal runaway is expected to be significantly lower.

So what does this change in concrete terms? For drivers, a longer-lasting and lighter electrical-system battery could mean fewer visits to the workshop. For independent repair shops, the work is shifting: Diagnostic equipment must be able to handle BMS communication, and chargers must offer suitable charging profiles. According to the assessment by heise online, wider adoption would reduce demand for conventional lead-acid replacement batteries and thus cut into part of the existing replacement-parts business.

BAIC is meanwhile looking beyond the small battery. The group’s in-house research department has developed a prismatic sodium-ion cell with more than 170 Wh/kg; it is expected to be capable of being largely charged in around 11 minutes at a high charging rate of 4C. CATL is already supplying a 45-kWh sodium-ion drive battery for the Changan Nevo A06. According to heise online, however, there is still no official development plan for broad series production beyond individual BAIC models. In Europe, Camel Group is working on a pre-development project with a major automaker, while Clarios is developing sodium-ion electrical-system batteries for original equipment and the aftermarket.