INR21700S-55P 21700 Battery: 5500mAh, 11A Fast Charge, 70A High-Drain Lithium-Ion Cell
If you are sourcing a high-rate 21700 battery for battery pack or base station designs, the INR21700S-55P is a strong candidate. It combines 5500mAh typical capacity, 3.6V nominal voltage, 11A fast charging, and up to 70A continuous discharge with an 80°C cutoff.
We supply this 21700 lithium-ion cell in bulk with competitive wholesale pricing and large stock.
Key Specifications at a Glance
| Item | INR21700S-55P |
|---|---|
| Cell format | Cylindrical 21700 lithium-ion cell |
| Nominal voltage | 3.6V |
| Standard discharge capacity | 5400mAh min / 5500mAh typ |
| Minimum energy | 19.4Wh |
| Charge cutoff voltage | 4.2V |
| Discharge cutoff voltage | 2.5V |
| Standard charge | 5.5A CCCV, 110mA cutoff |
| Max continuous charge | 11A |
| Max continuous discharge | 50A without 80°C cutoff; 70A with 80°C cutoff |
| Max pulse discharge | 175A for 10s at 25±2°C |
| Internal resistance | ≤4.0mΩ |
| DCR | ≤11mΩ at 50% SOC, 1C/10s |
| Dimensions | 21.35±0.15mm diameter × 70.7±0.2mm height |
| Weight | 68.0±1.5g |
| Shipping voltage | 3580–3600mV |
Performance Highlights for High-Drain 21700 Applications
The 5500mAh 21700 capacity gives pack designers a strong energy base, while the high-rate design supports demanding discharge profiles.
At the cell level, the 70A 21700 capability is specified with an 80°C temperature cutoff. Without that cutoff, the maximum continuous discharge is 50A. For short bursts, the cell supports 175A for 10 seconds at 25±2°C.
The 11A fast charge 21700 capability is useful for applications that need shorter charge times. Standard charging is 5.5A CCCV to 4.2V with a 110mA cutoff.
Low resistance helps reduce losses under high current. The cell is specified at ≤4.0mΩ internal resistance and ≤11mΩ DCR at 50% SOC, 1C/10s.
Cycle Life Depends on How You Use It
The INR21700S-55P offers different cycle-life ratings based on charge and discharge current:
- 1000 cycles to ≥80% capacity at 25°C, 5.5A charge / 5.5A discharge.
- 600 cycles to ≥60% capacity at 25°C, 8A charge / 30A discharge.
- 250 cycles to ≥60% capacity at 25°C, 11A charge / 30A discharge.
- 100 cycles to ≥60% capacity at -10°C, 2.75A charge / 11A discharge.
For long-life 21700 battery pack designs, thermal management and current margin matter. Running the cell at maximum current all the time will reduce cycle life compared with moderate current operation.
Safety and Pack Design Notes
Safety tests in the specification refer to GB31241-2022 / UN38.3 methods. The cell is tested for external short circuit, overcharge, forced discharge, low pressure, temperature cycling, vibration, drop, crush, heating, and heavy impact.
The cell itself is not a complete battery pack. A proper protection circuit is required. Recommended protection points include:
- Overcharge protection around 4.25V/cell.
- Over-discharge protection around 2.0V/cell.
- Overcurrent protection around 70A/cell.
- Precharge below 2.5V at ≤0.55A; stop if voltage does not recover above 3.0V.
- Do not use trickle charging.
- Keep charge voltage at or below 4.20V/cell, with charger accuracy designed so the cell never exceeds 4.23V.
- Connect cells by spot welding only. Do not solder directly or use ultrasonic welding.
- For series connections, use the same lot, shipping charge date, and capacity rank. Keep voltage difference within 20mV.
These design rules are important for anyone building a high drain 21700 battery pack or sourcing bulk 21700 cells for base station and industrial pack applications.
Wholesale 21700 Battery Price and Bulk Stock
We offer favorable wholesale pricing on the INR21700S-55P 21700 battery and maintain large stock for bulk orders.
Whether you need samples for evaluation, pilot-run quantities, or repeat bulk supply, we can support your project. Pricing depends on order quantity, destination, and shipping method.
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