Rechargeable lithium-ion cell Samsung INR21700-40T 3.6V 4000mAh 35A (21700)

Samsung INR21700-40T is a rechargeable lithium-ion cell in 21700 format with a nominal voltage of 3.6V and a rated capacity of 4000mAh. The cell is engineered to combine high energy density with a high continuous discharge capability, offering stable voltage under load and extended runtime for demanding portable power applications. Intended for use in assemblies with appropriate protection and charging systems, this cell supports applications that require both sustained energy storage and moderate-to-high discharge currents.

Advantages

The cell provides a balance of high capacity and a 35A continuous discharge capability, enabling longer run times without compromising the ability to deliver sustained current when needed. Its 21700 format increases usable energy per cell compared with smaller formats, while consistent voltage under load helps maintain device performance. When used in properly designed packs with battery management and thermal protection, the cell delivers reliable cycle life and predictable behavior across a range of temperatures and loads.

Suitable for

• Battery packs for e-bikes and electric scooters
• High-power flashlights and portable lighting
• Power tools and cordless equipment
• DIY battery packs and energy storage modules
• Hobbyist high-drain devices and custom electronics

Key specifications

• Cell format: 21700 cylindrical cell
• Nominal voltage: 3.6 V
• Rated capacity: 4000 mAh
• Continuous discharge current: up to 35 A
• Chemistry: lithium-ion (NMC-based INR type)
• Typical use case: high-energy and high-drain applications

How to use

Install the cell only into devices or battery packs designed for 21700 lithium-ion cells and ensure correct polarity. Use a compatible charger and a battery management system (BMS) or protection circuit to control charge and discharge limits, balancing and cell monitoring. Observe manufacturer recommendations for charge voltage and current limits and avoid charging at temperatures outside the cell’s safe operating range. Cells should be assembled into packs by qualified persons or professionals who can ensure proper mechanical fixation, electrical connections, and thermal management.

Usage recommendations

Operate the cell within recommended charge and discharge parameters, store at moderate state of charge in a cool, dry place for prolonged storage, and avoid exposing cells to mechanical damage, extreme temperatures, or water. Always use appropriate protection circuitry and follow local regulations for transport and disposal of lithium-ion cells.