Update: Nio announced that the first version of the Firefly EV, which will launch on April 19, will use demonstration Nio Group battery swap stations, a separate swap station network from what Nio-branded vehicles use. A later version and other models under the brand will support CATL’s Choco-SEB standard and Nio Group’s fifth generation on swap stations.

Nio and CATL announced a partnership to build a battery swap network together. Nio’s brand Firefly will adopt CATL Choco-SEB standard, and CATL will invest 2.5 billion yuan (346 million USD) into Nio Power, the company’s battery swap unit.

Nio and CATL signed an agreement today at CATL headquarters in Ningde, Fujian province. The two companies will jointly build battery swap stations for passenger cars of various brands across China.

The cooperation’s goal is to build the “world’s largest battery swap network for passenger cars,” accelerate the adoption of battery swap vehicles and services, and set a battery swap standard.

As part of the deal, Nio’s new brand, Firefly, will adopt CATL’s new battery swap standard, Choco-SEB. Firefly is not compatible with any of Nio’s current swap stations. CATL is said to “support Nio in developing battery swap network”.

The agreement highlights that both battery swap networks will run parallel. Nio-branded vehicles will continue using the existing Nio swap network, while Firefly will use CATL’s Choco swap standard.

CATL announced the Choco-SEB standard in December, along with 10 models from automakers such as Changan, SAIC, Wuling, and GAC Aion. These models will feature battery swap under the Choco standard. Models under the Firefly brand will join this alliance.

CATL CEO and founder Robin Zeng and Nio’s CEO and founder William Li attended the signing ceremony. Yang Jun, CATL’s battery swap GM, and Shen Fei, Nio’s senior VP, signed the agreement.

Li stated that the partnership between NIO and CATL represents a significant milestone, ushering battery swapping into a new stage of development.

On December 18 2024, CATL unveiled two standardized chocolate battery packs, 20# and 25#, designed for battery swapping. The company’s founder and CEO, Robin Zheng, announced that it plans to build 1,000 battery swap stations next year, with the ultimate goal of 30,000 swap stations in China.

“We will continue to promote the standardization of battery swapping, and the most important thing is the standardization of battery size,” said Zheng during CATL’s Battery Swap Ecosystem Conference in Xiamen.

The 20# and 25# choco batteries, officially called Choco-SEB (Swapping Electric Blocks) battery packs, will support lithium iron phosphate (LFP) and lithium nickel manganese cobalt (NMC) chemistry versions. They are designed for A0 to B class EVs and provide up to 600 km CLTC range.

CATL’s Choco-SEB swap stations will have 14 – 30 large battery compartments. It will take 100 seconds to change an empty battery for a full one, and the daily capacity is 822 swaps. The cost of using a Choco-SEB battery swap subscription will be 0.1 yuan/km (0.014 USD), according to CATL.