IFR21700 Cell Engineering Reference

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IFR21700 Cell Engineering Reference

Topwell's 21700 lifepo4 battery cell programme centres on the IFR21700-3000mAh (item TWE0501): a 3.2V nominal cylindrical cell rated 3000mAh at 0.2C discharge, measuring 21.7(±0.2) × 70.8(±0.2) mm and weighing roughly 63 g. Because the ifr21700 3000mah lifepo4 cell holds a 9A continuous and 15A peak discharge ceiling, ≤25 mΩ internal resistance and ≥2000 cycles to 80% capacity, it gives pack builders repeatable current headroom, clean 4S/8S/16S string math and a documented −20~60°C discharge window.

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21700 Lithium Battery 3.2V IFR21700-3000mAh LiFePO4 Rechargeable Cell

IFR21700 at a glance

3.2V

Nominal voltage

3000mAh

Capacity @0.2C discharge

21.7 × 70.8 mm

Diameter × height (±0.2 mm)

9A / 15A

Continuous / peak discharge

≤25 mΩ

Internal resistance

≥2000

Cycles to 80% capacity

≈63 g

Cell weight

1 year

Stated warranty

Single source of truth

Canonical IFR21700 Technical Specification Table

Every figure below is taken from the IFR21700 product page. Treat this table as the reference sheet when you compare this cell against another 21700 candidate, write a pack specification, or check a quotation line by line.

IFR21700, item TWE0501, in the 3.2V LiFePO4 cylindrical category.

Low-temperature 3.2V LiFePO4 cylindrical cell reference

Parameter	Specification	Remark
Model No.	IFR21700	Item No. TWE0501
Nominal voltage	3.2V	LiFePO4 chemistry
Nominal capacity	3000mAh	@0.2C discharge
Dimensions	21.7(±0.2) × 70.8(±0.2) mm max	Diameter × height
Cycle life	≥2000 times	Retaining ≥80% of initial capacity
Charge method	CC/CV with a dedicated lithium battery charger	Charge cut-off 3.6V
Discharge cut-off voltage	2.0V	Per cell
Standard charge current	600mA	Max continuous charge 3000mA
Standard discharge current	600mA	Max continuous discharge 9A
Peak discharge current	15A	Short-duration peaks only
Internal resistance	≤25 mΩ	Fresh cell
Weight	Approx. 63 g	Per cell
Operating ambient temperature	Charge 0~50°C, discharge −20~60°C	Recommended range
Storage temperature	−20~25°C (12 months); −20~35°C (3 months); −20~45°C (1 month)	Tiered by duration
Certificates	CE, CB, IEC62133, UL, PSE, RoHS, REACH, UN38.3, MSDS	Safety, environmental and transport
Management systems	ISO9001, ISO14001, BSCI	Quality and environmental management
Warranty	1 year	As stated on the product page

Transport documentation is supplied as UN38.3, MSDS and air/sea transport identification and classification reports. Confirm current certificate versions and destination-specific requirements when you place an order.

Mechanical fit

Dimensions, Tolerances and Space Budget

IFR21700 uses the familiar 21700 can format, so the mechanical question is rarely “does it fit at all” and almost always “how much clearance do I leave”. The ±0.2 mm tolerance applies to both the diameter and the max height.

21700 Lithium Battery 3.2V IFR21700-3000mAh LiFePO4 rechargeable cell dimensional reference

21.7(±0.2) mm diameter, 70.8(±0.2) mm max height, approx. 63 g.

Planning item	IFR21700 data	Design implication
Cell diameter	21.7 mm (±0.2)	Holder wells and cavities should clear the worst-case 21.9 mm
Cell height	70.8 mm max (±0.2)	Add height above the can for tabs, nickel strip, insulation and busbar
Cell weight	Approx. 63 g	4S1P ≈ 252 g and 16S1P ≈ 1.01 kg of cells, before BMS and enclosure
Single-row 4S length	4 × 21.7 mm = 86.8 mm	Minimum block length with no spacers, holders or end plates
Tolerance stack-up	±0.2 mm on diameter and height	Apply the tolerance to each cell in tightly stacked or press-fit cavities

Length, width and height of a finished block depend on cells per row plus holder walls, insulation paper, busbar thickness and the enclosure shell. Weight and length figures above are straightforward arithmetic on the published 63 g and 21.7 mm values.

Thermal envelope

Temperature Ranges, Storage Tiers and Derating

Two temperature tables matter in a real project: the operating window that decides whether the pack can run, and the storage tiers that decide how long it can sit on a shelf without losing capacity.

LiFePO4 cell thermal performance reference

Recommended ranges as published for the IFR21700 cell.

Condition	Recommended range
Charging	0~50°C
Discharging	−20~60°C
Storage up to 12 months	−20~25°C
Storage up to 3 months	−20~35°C
Storage up to 1 month	−20~45°C

Charging below 0°C falls outside the published charge range — outdoor and vehicle packs should include charge blocking or heating logic.
Cold discharge stays inside the −20~60°C window, but usable capacity drops as temperature falls; insulate or pre-warm winter-duty packs.
Long-term storage belongs in the 12-month tier at −20~25°C; the −20~45°C band is only rated for about one month.
Continuous high-temperature duty ages the cell faster, so keep sustained current below the 9A continuous limit and design airflow or heat spreading where the enclosure is sealed.

Configuration math

Pack-Sizing Quick Reference for IFR21700

Move from one cell to a finished pack configuration without recalculating each column. Voltage follows series count, capacity and current ceiling follow parallel count, and energy is the product of the two.

Wide-temperature 3.2V LiFePO4 cylindrical cell in a pack configuration reference

Strings scale by series count; current ceiling scales by parallel count.

Configuration	Nominal voltage	Pack capacity	Approx. energy	Continuous	Peak
4S1P	12.8V	3.0Ah	38.4Wh	9A	15A
8S1P	25.6V	3.0Ah	76.8Wh	9A	15A
16S1P	51.2V	3.0Ah	153.6Wh	9A	15A
4S2P	12.8V	6.0Ah	76.8Wh	18A	30A
8S2P	25.6V	6.0Ah	153.6Wh	18A	30A
16S2P	51.2V	6.0Ah	307.2Wh	18A	30A
16S4P	51.2V	12.0Ah	614.4Wh	36A	60A

Formulas: pack voltage = 3.2V × S · pack capacity = 3.0Ah × P · pack energy = voltage × capacity · discharge ceiling = 9A × P continuous and 15A × P peak. Cell-level values are taken from the IFR21700 product page; pack current assumes matched cells, balanced parallel strings and adequate wiring, and should be derated for temperature and connection losses.

Production and test evidence

Manufacturing Flow, 100% Testing and Certifications

Two claims carry most of the weight when qualifying a cell supplier: how consistently the cells are built, and what is verified before they leave the line. The IFR21700 page documents both.

2000-cycle 3.2V LiFePO4 cell production reference

Twelve documented production steps from electrode mixing to outbound quality control.

12-step production flow

01Materials mixing

02Coating

03Electrode piece rolling

04Electrode piece slitting

05Winding

06Into shell

07Tab welding & beading

08Injection

09Automatic laser welding

10Formation & capacity sorting

11Cycle test

12OQC test

Every cell is tested for 3 cycles before shipment, supporting the high consistency claim on capacity, voltage and resistance.
100% full test on appearance, voltage, capacity, resistance and size — a full pass per cell rather than a lot sample.
Capacity sorting at formation keeps parallel strings better matched, which matters for the 2P and 4P configurations above.

The supplier reports two decades in the battery field and ships by sea, air and express from Shenzhen, Shanghai and Hong Kong with dangerous-goods documentation such as UN38.3 and MSDS.

Application decisions

Match Your Use Case to a Cell Specification

Each card below pairs an application the supplier lists for this cell family with the specific published figure that governs the decision, and the check a buyer should run before committing to a pack design.

How to read the cards

The “spec fact” is a published IFR21700 value. The “buyer decision” is the engineering or commercial checkpoint that follows from it — string count, parallel count, thermal handling or storage policy.

Solar street light and lawn lamp

Spec fact3.2V nominal with a −20~60°C discharge window.

Buyer decisionMatch the string to the LED driver input window and confirm the all-night continuous draw stays inside 9A per cell.

Home energy storage, backup power and UPS

Spec fact≥2000 cycles to 80% capacity, associated with an 8–10 year use life.

Buyer decisionBuy on cost per cycle rather than peak power, and align inverter and BMS cut-offs with 3.6V / 2.0V per cell.

Golf cart, e-scooter and e-bike

Spec fact15A peak discharge per cell on top of 9A continuous.

Buyer decisionSize the parallel count so acceleration and hill-start inrush stay below 15A × P, and verify the controller’s peak demand.

Communication base station

Spec fact≤25 mΩ internal resistance with capacity, voltage and resistance sorting in production.

Buyer decisionInsist on matched parallel strings, and confirm the float-voltage window sits comfortably under the 3.6V charge cut-off per cell.

Power tools and garden tools

Spec fact9A continuous and 15A peak discharge; 3000mA maximum continuous charge.

Buyer decisionMeasure the tool’s stall and start-up current first, then choose 2P or 4P so the peak ceiling covers it with margin.

Emergency light, miner’s lamp and RV power

Spec factApprox. 63 g per cell at 3000mAh and 3.2V.

Buyer decisionRun the weight and runtime budget early: 3.0Ah × P per string, with cell weight multiplied across the whole pack.

Request a Quote, Sample or Custom Pack Support

Send your target voltage, capacity, continuous and peak current, enclosure dimensions and operating temperature range. Topwell supports OEM/ODM projects, sample evaluation for pilot builds and bulk orders, and can provide the product information PDF, certification documentation and dangerous-goods transport paperwork with your quotation.

View the IFR21700 Cell

Frequently Asked Questions

what are the headline specifications of the ifr21700 cell?

ifr21700 (item twe0501) is a 3.2v nominal lifepo4 cylindrical cell rated 3000mah at 0.2c discharge, measuring 21.7(±0.2) × 70.8(±0.2) mm and weighing approximately 63 g.

what continuous and peak current can one cell deliver?

standard discharge is 600ma, the maximum continuous discharge current is 9a and the peak discharge current is 15a, with internal resistance of ≤25 mω. pack-level current capability scales with the number of parallel cells.

how many cells are needed for 12v, 24v and 48v packs?

with a 3.2v nominal cell, a 4s string gives 12.8v nominal, an 8s string 25.6v and a 16s string 51.2v. using a 3.6v charge cut-off and a 2.0v discharge cut-off, a 4s pack charges to 14.4v and discharges to 8.0v.

what temperature ranges apply to charging, discharging and storage?

charging is recommended from 0~50°c and discharging from −20~60°c. storage is −20~25°c for up to 12 months, −20~35°c for up to 3 months and −20~45°c for up to 1 month.

what is the cycle life and expected service life?

cycle life is ≥2000 cycles while retaining at least 80% of initial capacity, which the product page associates with an 8–10 year use life in suitable applications.

what certifications, warranty and testing does the cell carry?

the cell is listed with ce, cb, iec62133, ul, pse, rohs, reach, un38.3 and msds documentation, plus iso9001, iso14001 and bsci quality and environmental management, and a 1-year warranty. every cell is tested for 3 cycles and receives a 100% full test on appearance, voltage, capacity, resistance and size.

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