Nio subsidiary Firefly to integrate CATL’s battery swap technology

It was already known before the world premiere that the small electric car from Firefly unveiled in December will use a different battery swap system to Nio and Onvo – the dimensions alone mean that the standard Nio batteries with 75, 100 or, in China, up to 150 kWh will not fit into the four-metre-long small car with a wheelbase of 2.62 metres.

Although Nio agreed on a battery swap cooperation with CATL for its Firefly brand this week, this only applies to upcoming models that are currently still in development – but not to the Firefly EV presented in December. This will go on sale on 19 April, as Nio has now announced – and at the same time confirmed that its own battery exchange stations will initially be set up for the Firefly EV.

Initially, “demonstration stations will be set up for battery swapping in cities with a high number of users,” explained Daniel Jin, President of Firefly. In the future, the model will be connected to Nio’s fifth-generation battery exchange stations and thus integrated into Nio’s battery exchange system, Jin continues. In China, the company is currently setting up the fourth-generation stations for the Nio and Onvo brands. This means that there will initially be two Nio systems, which will then be merged in the next generation.

Firefly to switch to CATL battery system

However, a much bigger change is in store for the upcoming Firefly models after the four-metre-long small car: The other Firefly models will switch to CATL’s Choco-SEB system. Almost exactly a year ago, Nio and CATL signed a cooperation agreement to develop longer-lasting e-car batteries for Nio’s battery replacement requirements – which has now resulted in Nio switching to the CATL system, at least for Firefly. This step has not yet been confirmed for the Onvo and Nio brands.

It is now clear that Nio is utilising a cooperation agreement concluded with CATL for Firefly almost exactly one year ago. CATL is already the main supplier for Nio’s battery cells, but the car manufacturer is responsible for assembling the packs itself.

The CATL subsidiary CAES (Contemporary Amperex Energy Service Technology) presented this Choco-SEB system (SEB stands for Swapping Electric Block and ‘Choco’ refers to the look of the SEB) for the first time at the beginning of 2022. At the end of 2024, CATL then presented two battery packs for the swap system – the 20# for smaller cars and the 25# for larger vehicles. There is already a striking parallel today: according to the application for approval, the 42.1 kWh batteries with LFP cells from the Firefly EV will be assembled by Sunwoda – but there were rumours early on that Sunwoda would only be responsible for assembly and that the cells would come from another company. This could be CATL, which is already the main supplier for Nio. This is because the 20#, which is intended for vehicles such as the Firefly EV, also has 42 kWh in the LFP version – this ‘coincidence’ has already led to speculation in China that it could be CATL’s Choco-SEB system. This battery can be used via the CATL tariff for 369 yuan per month (around €48/month).

Although CATL’s Choco-SEBs are making their debut in Nio’s budget brand Firefly, the larger 25# packs could also form the basis for future Nio models – but this has not been confirmed. However, the joint statement states that they want to “promote the development and adoption of national standards for battery swap technology in China to further enhance battery compatibility across different brands and models.” It would therefore make sense not to permanently operate two systems in parallel, especially as the manufacturer-open CATL approach is likely to be more widespread than the Nio system.

In order to consolidate the strategic partnership, CATL is investing up to 2.5 billion yuan (316 million euros) in Nio Power, the car manufacturer’s energy division. The aim is to achieve synergy effects through exchange and cooperation in the areas of technology, capital and business.

“The strategic cooperation between NIO and CATL marks a pivotal moment, propelling battery swapping into a brand-new phase,” says Nio CEO William Li. “With the support from CATL, NIO’s swapping network will extend to more regions and provide better services. This cooperation is beyond capital investment—it facilitates mutual empowerment in technological standards and service systems.” CATL CEO Robin Zeng added: “Leveraging our Choco-Swap and the parallel operations of both CATL’s and NIO’s networks, we are able to build a smart power network that caters to a wide range of needs across multiple levels and dimensions.”

cnevpost.com (Firefly), cnevpost.com (cooperation with CATL)