Cylindrical 21700 High-Power Cell
FEB 55S
Cylindrical 21700 cell delivering 5.5 Ah capacity, 264 Wh/kg energy density and 30 A maximum discharge rate.
Overview
The FEB 21700-55S is a high-power Li-ion cylindrical 21700 cell designed for applications that demand sustained high current. Released in 2026 and with the manufacturer based in China, this cylindrical 21700 cell delivers 5.5 Ah capacity and 19.8 Wh of energy at a nominal voltage of 3.6 V, with a maximum continuous discharge capability of 30 A, making it well suited to high-power systems. The silicon-bearing anode contributes to that energy density. Its 264 Wh/kg gravimetric energy density is above the 21700 cylindrical median of 257 Wh/kg in the About:Energy battery library.
Key Features
High discharge rate: 30 A continuous (5.5 C)
Energy density: 264 Wh/kg
Power density: 1,440 W/kg
Capacity: 5.5 Ah nominal capacity
Applications: drones, motorsports, e-mobility
Technical Specifications from the Manufacturer
Parameter
Manufacturer
FEB
Model
21700-55S
Type
Li-ion
Form factor
Cylindrical 21700
Country of origin
China
Release year
2026
Nominal voltage
3.6
Energy capacity [Wh]
19.8
Capacity [Ah]
5.5
Gravimetric energy density [Wh/kg]
264
Gravimetric power density [W/kg]
1440
Max continuous discharge [A]
30
Volume [cm³]
26.1191
Mass [g]
75
Positive electrode (cathode)
Ni-based
Negative electrode (anode)
Graphite/Si additive
Value
Applications & Use‑Cases
The FEB 21700-55S is well suited to the following applications due to its 21700 format and high power performance.
Drones: Demands high gravimetric power density for thrust and payload capacity, rapid current response for flight control, and stable voltage delivery across dynamic flight profiles.
Motorsports: Demands sustained high discharge under competitive load profiles, rapid transient response for acceleration, and thermal stability to maintain performance during race conditions.
E-Mobility: Requires balanced energy and power density for range and acceleration, high cycle life for daily use, and robust calendar life to ensure long-term reliability.
General Applications: Suitable for applications requiring reliable lithium-ion performance with proven cycle life, consistent capacity delivery, and operational safety across diverse use cases.
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Performance & Model Data
Below are modelled performance metrics for the FEB 21700-55S across key indicators, including constant current behaviour, rate capability, temperature dependence, and available power under representative drive cycle conditions.
Constant Current Voltage
Access FEB 55S constant-current discharge curves in Voltt to size your pack against the voltage window your system actually needs. (Chart shown is illustrative, not 55S data.)
Constant Current Temperature
Access FEB 55S thermal discharge data in Voltt to specify cooling and cell spacing before you commit to a pack layout. (Chart shown is illustrative, not 55S data.)
Pulse Power Behaviour
Access FEB 55S pulse power maps in Voltt to set peak current limits and parallel count for your worst-case load. (Chart shown is illustrative, not 55S data.)
Dynamic Profile Response
Access FEB 55S mission profile simulations in Voltt to prove the pack holds up over a real duty cycle before you build it. (Chart shown is illustrative, not 55S data.)
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Case Studies
See how we helped McMurtry reduce cell evaluation time by 70% through data driven testing and modelling.
Motorsports
McMurtry Automotive: Faster cell evaluation
McMurtry Automotive used The Voltt and validated cell models to evaluate the transition from the Molicel P45B to P50B during early pack concept development.
Side by side modelling enabled rapid comparison of electrical and thermal behaviour, avoiding lengthy physical test campaigns. This approach reduced cell evaluation time by seven months, allowing the team to lock in cell selection and pack assumptions earlier while lowering technical risk and accelerating vehicle development.
Comparison with Related Cells
Compare the FEB 21700-55S with similar Cylindrical 21700 cells offering comparable capacity and performance characteristics.
Model
Capacity
Max Discharge
Typical Use
Access Cell Data
Manufacturer Background
FEB
FEB is a Chinese cylindrical lithium-ion cell manufacturer
Far East Battery, trading as FEB, was founded in 2009 and is a core subsidiary of the listed Far East Smart Energy group. The company develops and manufactures cylindrical lithium-ion cells, modules and complete pack systems, with the 18650 and 21700 formats forming the backbone of its catalogue. FEB serves electric vehicles, stationary energy storage, electric two-wheelers, power tools and consumer electronics, giving it volume across several high-turnover segments. It has pushed mass-produced 21700 capacity upward in successive steps, releasing higher-capacity variants ahead of much of the market while holding the same cell dimensions. Its position rests on capacity records within established formats rather than novel chemistries.
Frequently Asked Questions
What is the capacity and voltage of the FEB 21700-55S?
The FEB 21700-55S has a nominal capacity of 5.5 Ah and a nominal voltage of 3.6 V, providing 19.8 Wh of energy per cell.
What is the maximum continuous discharge capability of the FEB 21700-55S?
The FEB 21700-55S supports continuous discharge rates up to 30 A, delivering a power density of 1,440 W/kg.
How much does the FEB 21700-55S weigh and what is its volume?
The cell has a mass of 75 g and a volume of 26.1 cm³.
In which industries is the FEB 21700-55S commonly used?
The FEB 21700-55S is used across drones, motorsports, e-mobility, applications that demand sustained high current.
How does the FEB 55S compare with the Samsung 58E?
Comparing the FEB 55S with the Samsung 58E: capacity 5.5 Ah against 5.5 Ah; maximum continuous discharge 30 A against 11 A; energy density 264 Wh/kg against 270 Wh/kg; mass 75 g against 74 g. Both datasheets can be compared side by side in The Voltt.
What chemistry and format is the FEB 55S?
The FEB 55S is a cylindrical 21700 cell with a Ni-based cathode and a Graphite/Si additive anode. It has a nominal voltage of 3.6 V and a volume of 26.1 cm³. Its full datasheet is free to view in The Voltt.
