Cylindrical 21700 High-Power Cell
Samsung 51X
Cylindrical 21700 cell delivering 5 Ah capacity with 247 Wh/kg energy density and 15 A maximum discharge rate.
Overview
The Samsung 51X is a lithium-ion cylindrical 21700 cell designed for applications that demand reliable performance and consistent capacity delivery. Released in 2023 and with the manufacturer based in South Korea, this cylindrical 21700 cell delivers 5 Ah capacity and 18.3 Wh of energy at a nominal voltage of 3.65 V, with a maximum continuous discharge capability of 15 A, making it well suited to energy-focused applications requiring extended runtime.
Key Features
High discharge rate: 15 A continuous (3.0 C)
Energy density: 247 Wh/kg
Power density: 740 W/kg
Applications: aviation, motorsports, e-mobility
Technical Specifications from the Manufacturer
Parameter
Manufacturer
Samsung
Model
51X
Type
Li-ion
Form factor
Cylindrical 21700
Country of origin
South Korea
Release year
2023
Nominal voltage
3.65
Energy capacity [Wh]
18.25
Capacity [Ah]
5
Gravimetric energy density [Wh/kg]
247
Gravimetric power density [W/kg]
740
Max continuous discharge [A]
15
Volume [cm³]
24.6
Mass [g]
74
Positive electrode (cathode)
Negative electrode (anode)
Value
Applications & Use‑Cases
The Samsung 51X is well suited to the following applications due to its cylindrical 21700 form factor and high power performance.
Aviation: Requires high specific energy for extended flight duration, high power-to-weight ratio for climb performance, and reliable operation across wide temperature ranges at altitude.
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 Samsung 51X across key indicators, including constant current behaviour, rate capability, temperature dependence, and available power under representative drive cycle conditions.
Constant Current Voltage
Access Samsung 51X constant-current discharge curves in Voltt to size your pack against the voltage window your system actually needs. (Chart shown is illustrative, not 51X data.)
Constant Current Temperature
Access Samsung 51X thermal discharge data in Voltt to specify cooling and cell spacing before you commit to a pack layout. (Chart shown is illustrative, not 51X data.)
Pulse Power Behaviour
Access Samsung 51X pulse power maps in Voltt to set peak current limits and parallel count for your worst-case load. (Chart shown is illustrative, not 51X data.)
Dynamic Profile Response
Access Samsung 51X 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 51X 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 Samsung 51X with similar Cylindrical 21700 cells offering comparable capacity and performance characteristics.
Model
Capacity
Max Discharge
Typical Use
Access Cell Data
Manufacturer Background
Samsung SDI
Samsung SDI is a South Korean manufacturer producing cylindrical, prismatic and pouch lithium-ion cells
Samsung SDI is headquartered in Yongin, South Korea, and manufactures lithium-ion cells across cylindrical, prismatic and pouch formats. Its cylindrical 18650 and 21700 cells cover both energy-led and high-power variants, using high-nickel NCA and NCM cathode chemistry, and are widely used in power tools, electric two-wheelers, vacuum cleaners and vehicle packs. The model codes denote capacity class and rate capability, and the range is among the most thoroughly characterised in independent testing. Manufacturing spans South Korea, China, Hungary and the United States, including joint ventures with automotive partners. Its position rests on consistent cell-to-cell quality and a catalogue that has changed slowly and predictably.
Frequently Asked Questions
What is the capacity and voltage of the Samsung 51X?
The Samsung 51X has a nominal capacity of 5 Ah and a nominal voltage of 3.65 V, providing 18.3 Wh of energy per cell.
What is the maximum continuous discharge capability of the Samsung 51X?
The Samsung 51X supports continuous discharge rates up to 15 A, delivering a power density of 740 W/kg.
How much does the Samsung 51X weigh and what is its volume?
The cell has a mass of 74 g and a volume of 24.6 cm³.
In which industries is the Samsung 51X commonly used?
The Samsung 51X is used across aviation, motorsports, e-mobility, applications that demand high power delivery and reliable performance across demanding duty cycles.
How does the Samsung 51X compare with the Samsung 50U?
Comparing the Samsung 51X with the Samsung 50U: capacity 5 Ah against 5 Ah; maximum continuous discharge 15 A against 60 A; energy density 247 Wh/kg against 250 Wh/kg; mass 74 g against 72 g. Both datasheets can be compared side by side in The Voltt.
What chemistry and format is the Samsung 51X?
The Samsung 51X is a cylindrical 21700 cell. It has a nominal voltage of 3.65 V and a volume of 24.6 cm³. Its full datasheet is free to view in The Voltt.
