Chinese automaker Changan Automobile has delivered the first 1,000 Oshan 520 electric sedans equipped with CATL’s Choco-SEB swappable battery system to a taxi company in Chongqing, marking the commercial debut of the battery technology.
The delivery comes as battery giant CATL and Changan accelerate rollout of the Choco-SEB ecosystem. Chongqing is currently home to 34 exchange stations compatible with the system, with the number expected to reach 50 by year-end. Each station can hold up to 30 batteries and enables swaps in under 100 seconds, significantly faster than the three-minute average for rival systems such as those from Nio.
“The Oshan 520 impressed with its range, performance and ability to leverage the fast-swap battery model, ideal for intensive fleet operations like taxis,” a Changan spokesperson said at the handover ceremony, according to Chinese media reports.
The Oshan 520, an electric version of the combustion-based Changan Eado, is powered by a 105 kW motor and delivers a range of up to 515 kilometres under the CLTC test cycle. The sedan uses the 25# variant of CATL’s Choco-SEB battery pack, which is suited for vehicles with wheelbases up to 2.90 metres. In Chongqing, the vehicles are reportedly fitted with LFP-based 56 kWh packs.
Originally unveiled under the Evogo concept in 2022, CATL’s Choco-SEB—short for “Swapping Electric Blocks”—was designed for flexibility, with modules resembling chocolate bars. While early concepts allowed for variable block configurations, current models come in two fixed sizes: the 20# pack for smaller vehicles and the 25# for mid-sized cars.
Changan is not expected to remain the only automaker using the technology. At least ten models are expected to be compatible with Choco-SEB by year-end, including the GAC Aion S, SAIC Maxus Mifa 9, Hongqi E-QM5, and Wuling Bingo.
CATL aims to deploy 1,000 passenger vehicle battery-swap stations in China by the end of 2025, with additional support from partner-operated sites. Separately, the company is planning 300 swap stations for electric trucks based on its larger 75# battery module.