Nio Firefly Battery

The 2025 Nio Firefly battery uses LFP cells from Sunwoda and was originally suggested it would be to the CATL Choco-SEB swappable standard. However, see comment at end, this ended up being designed to be supported by the 5th gen Nio swap stations.

Metrics

  • Gravimetric Density
    • Energy = 134 Wh/kg
    • Power = 372 W10s/kg
    • Charge = 318 Wcont/kg

Specifications

  • Usable Energy = 41.2 kW (total = 42.1 kWh)
    • SoC Window = 97.9%
  • Nominal Voltage = 358.4 V
  • Nominal Capacity = 117.5 Ah
  • Peak Power ~ 116 kW10s
  • Pack Mass = 314 kg
  • Configuration = 1 # packs
    • 112 s 1 p
    • Total # cells = 112
Nio Firefly 2025 battery pack in chassiis image

How many people with fast charge this pack when it can be swapped or easily charged overnight at home?

Charging

  • Peak charge power = 100 kW
  • Charge time (10 to 80% = 28 minutes

The battery pack looks very standard.

This post has been built based on the support of and sponsorship from: Quarto Technical Services, Eatron Technologies and About:Energy

Cell

Cell is made by Sunwoda and this is the first time Nio have used there cells in a product.

  • Chemistry = LFP
  • Format = Prismatic
    • Capacity = 117.5 Ah
    • Nominal voltage = 3.2 V
    • Nominal energy = 375.9 Wh

References

  1. Firefly, Nio Firefly
  2. NIO and CATL Form Strategic Partnership on Battery Swapping, Nio Newsroom

See also: Benchmarking Battery Packs, Choco-SEB

2 thoughts on “Nio Firefly Battery”

  1. Yup, this is not the Choco-SEB compatible pack. Firefly is in a messy situation where it was originally going to have dedicated compact swap stations, but they decided last minute to integrate the brand’s packs into Nio’s 5th gen swap stations instead; they even showcased a working model shortly before the switch. I believe they said it was because they underestimated the bureaucracy and build time of swap stations in Europe compared to their experience in China, likely making the dedicated station’s size advantage for more quick and flexible installation irrelevant. The gen 5 Nio stations are only supposed to start appearing in August ’25 at the soonest.

    Later, they announced the brand’s cooperation with the Choco-SEB standard, but that will only be for following models starting next year at the earliest; the current model won’t be compatible.

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