The INR21700-50 is a 5000 mAh NCM cell in the 21700 format — 18 Wh per cell at 3.6 V nominal, up to ~250 Wh/kg at ≤72 g. It ships in two builds: the high-power 50D and the energy-optimized 50E. This page lays out the full factory test specifications; if you are deciding between the two builds, see 50D vs 50E compared.
Basic specifications
| Parameter | INR21700-50D | INR21700-50E |
|---|---|---|
| Nominal capacity (0.2C to 2.5 V) | 5000 mAh | 5000 mAh |
| Minimum capacity | 4900 mAh | 4900 mAh |
| Nominal voltage | 3.60 V | 3.60 V |
| Charge limit voltage | 4.20 V (4.25 V absolute upper limit) | 4.20 V (4.25 V absolute upper limit) |
| Discharge cut-off voltage | 2.50 V | 2.50 V |
| AC internal resistance (1 kHz) | ≤18 mΩ | ≤18 mΩ |
| Standard charge | 0.2C CC/CV to 4.20 V, 0.01C cut-off | 0.2C CC/CV to 4.20 V, 0.01C cut-off |
| Max continuous charge | 1C (5 A) | 0.5C (2.5 A) |
| Max continuous discharge | 3C (15 A) | 3C (15 A) |
| Max pulse discharge | 5C (not for cycling) | 5C (not for cycling) |
| Weight | ≤72 g | ≤72 g |
| Max size with PET sleeve | Ø21.7 ± 0.15 × 70.9 ± 0.2 mm | Ø21.0 ± 0.15 × 70.0 ± 0.2 mm |
| Charge temperature | 0 to 50 °C | 0 to 50 °C |
| Discharge temperature | −20 to 60 °C | −20 to 60 °C |
| Delivery voltage | ≥3.60 V (within 10 days ex-factory) | ≥3.60 V (within 10 days ex-factory) |
New to these terms? See the C-rate, capacity and cycle life glossary.
Discharge performance
Fully charged per the standard procedure, at 25 ± 2 °C:
| Test | Requirement (both builds) |
|---|---|
| 0.2C constant-current discharge to 2.5 V | ≥280 min |
| 1C constant-current discharge to 2.5 V | ≥54 min |
Cycle life
Cycle testing charges at 0.5C CC/CV (0.01C cut-off) with 10-minute rests between steps, until three consecutive discharges fall to 80% of the first-cycle capacity:
| Charge / discharge rate | 50D | 50E |
|---|---|---|
| 1C / 1C | ≥600 cycles | — |
| 0.5C / 1C | — | ≥800 cycles |
| 0.5C–1C / 3C | ≥300 cycles | ≥300 cycles |
Rate capability
Capacity retention when discharging at higher currents (charged 0.5C CC/CV, discharged to 2.5 V at 25 ± 2 °C, relative to the reference rate):
| Discharge rate | 50D | 50E |
|---|---|---|
| 1C | ≥97% | ≥97% |
| 2C | ≥95% | ≥95% |
| 3C | ≥92% | ≥93% |
Temperature performance
Relative discharge capacity at 0.2C versus the 25 °C reference:
| Ambient temperature | 50D | 50E |
|---|---|---|
| 55 °C | ≥95% | ≥98% |
| 0 °C | ≥85% | ≥85% |
| −10 °C | ≥80% | ≥80% |
| −20 °C | ≥60% | ≥70% |
Charge retention and storage
- 28-day retention: fully charged and stored at 25 ± 2 °C for 28 days, the cell retains ≥90% of nominal capacity (≥4500 mAh; ≥270 min at 0.2C).
- 12-month storage: stored at 40–50% state of charge at 25 ± 2 °C, the cell still delivers ≥4500 mAh after a standard recharge.
- Recommended storage windows: −5 to 45 °C up to one month, 0 to 45 °C up to six months, 20 to 25 °C for a year (0–60% RH).
Safety and abuse testing
Both builds pass the full factory abuse program with no fire and no explosion:
| Test | Condition |
|---|---|
| External short circuit | ≤80 mΩ circuit, monitored to temperature peak or 24 h; surface stays <150 °C |
| Overcharge | 1C forced charge past the limit voltage until current ≈ 0 A |
| Over-discharge | 0.2C discharge to 0 V |
| Forced discharge | 1C reverse charge for 90 min |
| Impact | 9.1 kg weight dropped 0.61 m onto a Ø15.8 mm bar across the cell |
| Crush | 13 kN between flat plates |
| Hot oven | Heated at 5 °C/min to 130 °C, held 30 min |
| Low pressure | 11.6 kPa (altitude simulation) for 6 h |
| Vibration | 0.8 mm amplitude, 10–55 Hz sweep, ~90–100 min, three axes |
| Free fall | 1.0 m drop, two per orientation |
Cells are UN38.3 transport tested and ship at 40–50% state of charge (3.60–3.65 V) — see battery shipping documents for the paperwork.
Ordering
Wholesale pricing, MOQ, batch capacity/IR binning reports and the full official datasheet (PDF) are provided after a short inquiry. Request the INR21700-50 datasheet & quote →