Cylindrical 21700 High-Power Cell
Reliance RU50
Cylindrical 21700 cell delivering 5 Ah capacity and 50 A maximum discharge rate.
Overview
The Reliance RU50 is a high-power lithium-ion cylindrical 21700 cell designed for applications that demand very high continuous discharge rates. Released in 2026 and with the manufacturer based in China, this cylindrical 21700 cell delivers 5 Ah capacity and 18.0 Wh of energy at a nominal voltage of 3.6 V, with a maximum continuous discharge capability of 70 A, making it well suited to high-power systems operating under aggressive discharge profiles. A continuous discharge capability of 14.0 C places the RU50 among the highest-rated cells in the 21700 format within the Voltt library.
Key Features
Extremely high discharge rate: 70 A continuous (14.0 C)
Charging rate: 3.0 C charging rate
Applications: aviation, motorsports, drones
Technical Specifications from the Manufacturer
Parameter
Manufacturer
Reliance
Model
INR21700-RU50
Type
Li-ion
Form factor
Cylindrical 21700
Country of origin
China
Release year
2026
Nominal voltage
3.6
Energy capacity [Wh]
18
Capacity [Ah]
5
Gravimetric energy density [Wh/kg]
269
Gravimetric power density [W/kg]
3761
Max continuous discharge [A]
70
Volume [cm³]
25.1676
Mass [g]
67
Positive electrode (cathode)
Ni-based
Negative electrode (anode)
Value
Applications & Use‑Cases
The Reliance RU50 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.
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.
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 Reliance RU50 across key indicators, including constant current behaviour, rate capability, temperature dependence, and available power under representative drive cycle conditions.
Constant Current Voltage
Access Reliance RU50 constant-current discharge curves in Voltt to size your pack against the voltage window your system actually needs. (Chart shown is illustrative, not RU50 data.)
Constant Current Temperature
Access Reliance RU50 thermal discharge data in Voltt to specify cooling and cell spacing before you commit to a pack layout. (Chart shown is illustrative, not RU50 data.)
Pulse Power Behaviour
Access Reliance RU50 pulse power maps in Voltt to set peak current limits and parallel count for your worst-case load. (Chart shown is illustrative, not RU50 data.)
Dynamic Profile Response
Access Reliance RU50 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 RU50 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 Reliance RU50 with similar Cylindrical 21700 cells offering comparable capacity and performance characteristics.
Model
Capacity
Max Discharge
Typical Use
Access Cell Data
Manufacturer Background
Reliance
Reliance is a Chinese manufacturer of high-power cylindrical lithium-ion cells
Reliance is a Chinese cell manufacturer producing cylindrical lithium-ion cells in the 21700 format, built on a tabless electrode architecture that lowers internal resistance and improves heat rejection under sustained load. Its RS and RP model codes denote the high-rate and high-capacity lines, with the trailing figure indicating rated capacity. The cells are aimed at electric bicycles and light electric vehicles, karting and motorsport, power tools and other applications where continuous discharge rather than pack energy sets the requirement. The company entered the market recently and competes directly with the established high-power cylindrical suppliers. Its relevance lies in bringing tabless construction to a competitive price point.
Frequently Asked Questions
What is the capacity and voltage of the Reliance RU50?
The Reliance RU50 has a nominal capacity of 5 Ah and a nominal voltage of 3.6 V, providing 18.0 Wh of energy per cell.
What is the maximum continuous discharge capability of the Reliance RU50?
The Reliance RU50 supports continuous discharge rates up to 70 A.
How much does the Reliance RU50 weigh and what is its volume?
Physical dimensions are not specified for this cell.
In which industries is the Reliance RU50 commonly used?
The Reliance RU50 is used across aviation, motorsports, drones, applications that demand very high power output and thermal management under extreme discharge.
What is The Voltt and how does it accelerate cell evaluation?
The Voltt holds 500+ verified commercial cell datasheets alongside validated simulation models built from cells characterised in About:Energy's own lab. Engineers screen candidates against their real duty cycle before buying hardware, which cut cell evaluation time by seven months for McMurtry Automotive and reduces evaluation cycles by up to 70%.
What data can be extracted using The Voltt?
Constant-current discharge curves at multiple C-rates, DC internal resistance against state of charge and temperature, pulse power maps, thermal response, and full mission-profile simulation with user-defined pack configurations. Models are available as equivalent circuit, thermal, physics-based and degradation formats, exportable for use in MATLAB, Simulink and Python workflows.
