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SAMSUNG INR21700-40T

SAMSUNG INR21700-40T

Technical Specifications

Cell Type: Lithium-ion rechargeable cylindrical cell (21700 format)
Nominal Voltage: ~ 3.6 V
Typical Capacity: Min 4,000 mAh (Rated capacity min ~3,900 mAh)
Dimensions: Diameter Max ~21.22 mm, Height Max ~70.30 mm
Weight: Max ~70.0 g

Max Charge Voltage: 4.20 V 
Discharge Cut-off Voltage: 2.5 V
Max Continuous Discharge Current: 35 A (Without temperature cut) / 45 A (With 80 °C temperature cut)
Cycle Life: After 250 cycles at 6 A charge / 35 A discharge, capacity ≥ ~2,400 mAh (≈ 60% of initial)
Operating Temperature Range: Charge: 0 °C to 45 °C; Discharge: –20 °C to 60 °C (surface temp results up to 80 °C) 

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Key Performance Highlights

  1. Very High Discharge Capability: Supports continuous discharge up to 35 A, and up to 45 A with thermal cutoff at 80 °C.
  2. Good Capacity: Rated standard discharge capacity is 4,000 mAh, with a minimum rated capacity of ~3,900 mAh under 10 A discharge.
  3. Low Internal Resistance: Initial AC internal impedance ≤ 12 mΩ (measured at 1 kHz) after standard charge.
  4. Fast Charging Capability: Charging support at 6 A (rated) and standard 2 A with CC-CV profile up to 4.20 V.
  5. Cycle Life: Rated for 250 cycles, retaining ≥ 2,400 mAh (~60% of standard capacity) when discharged at 35 A.
  6. Wide Discharge Rate Performance: At 20 A retains ~95%, at 30 A ~93%, and at 40 A ~90% of capacity (relative to 10 A discharge).
  7. Robust Temperature Performance: Discharge capacity remains stable across a wide temperature range (–20 °C to 60 °C) per spec.
  8. Durable Design: Physical dimensions: max height ~70.30 mm, diameter ~21.22 mm; max weight 70 g.
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INR21700-40T certificatesMSDS, UN38.3, UL, CB, IEC62133, BIS, etc.

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Frequently Asked Questions

What are the key electrical and mechanical parameters?

  • Standard discharge capacity: minimum ~4,000 mAh; rated capacity: ~3,900 mAh.
  • Nominal voltage: 3.6 V.
  • Cell dimensions: up to 70.30 mm height × 21.22 mm diameter.
  • Weight: 70 g max per datasheet.

What are the appropriate charge / discharge protocols for pack design?

  • Charging method: CC-CV (constant current / constant voltage), up to 4.20 V.
  • Standard charge current: ~2 A; rapid (“rated”) charge: up to ~6 A.
  • Discharge cutoff voltage: 2.5 V.

What is the continuous and peak discharge current?

  • Continuous discharge: 35 A (surface temperature based, no thermal cut) per datasheet.
  • With thermal cutoff (at ~80 °C), discharge up to 45 A is specified.
  • Pulse discharge (short bursts) of up to ~70 A potentially possible per third-party spec listing.

What is the expected cycle life under realistic load conditions?

  • Cycle life spec: ≥ 250 cycles to 60% of original capacity when charged at 6 A and discharged at 35 A.
  • Designers should account for capacity fade in high-power applications, especially for high-cycle or high-rate use cases.

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