High-C-rate Capacity Remains Stable! Yichuan New Energy INR21700-50PL Full-Tab Battery Cell Review
Introduction
As cylindrical lithium-ion battery cells continue to evolve toward higher capacity, higher discharge rates, and improved safety, the 21700 format has become a mainstream choice for energy storage power supplies, power tools, high-power portable devices, and other applications due to its balanced volumetric energy density and power performance.
Yichuan New Energy is a professional manufacturer specializing in the R&D and production of cylindrical power and energy-storage cells. Leveraging technologies such as a full-tab design and LATP cathode coating, Yichuan has developed the INR21700-50PL high-capacity power cell.
With a nominal capacity of 5000mAh, the cell supports 3C fast charging and up to 12C continuous discharge, with a nominal internal resistance of ≤5mΩ. It combines long runtime with high-power output capability.
This review provides a comprehensive evaluation of the cell, covering its appearance, manufacturing details, specifications, internal resistance, multi-rate charging performance, multi-rate discharge performance, and temperature characteristics during charging and discharging.
Appearance
The cell is wrapped in a gray heat-shrink film. The film surface is smooth and closely fitted to the steel casing without obvious gaps. Complete product specifications are laser-marked on the middle section of the casing, while the positive (+) and negative (-) polarity markings are shown on the two ends.
The printed markings are clear and legible. The key specifications include:
Model: INR21700-50PL
Nominal voltage: 3.6V
Nominal energy: 18.00Wh
Nominal capacity: 5000mAh
Brand: YICHUAN
Production batch: 26G18
Serial number: 02219234
The positive terminal uses an LATP coating, which helps reduce interfacial side reactions, improve lithium-ion conductivity, reduce interfacial impedance, enhance thermal safety, and delay thermal runaway, while also maintaining low-temperature performance.
The negative terminal features a flat steel casing bottom with a characteristic spiral-pattern stamping in the center, reflecting the internal winding structure of the cylindrical cell.
Dimensions & Weight
Measured dimensions:
Height: approximately 70.9mm
Diameter: approximately 21.3mm
Weight: approximately 69g
These measurements are highly consistent with the manufacturer’s specifications.
Specification Overview
The Yichuan New Energy INR21700-50PL full-tab cell has a nominal capacity of 5000mAh and a minimum capacity of 4950mAh.
Key electrical specifications include:
Nominal voltage: 3.6V
Charge cut-off voltage: 4.2V
Discharge cut-off voltage: 2.5V
Standard charging current: 0.5C
Standard discharge current: 0.2C
Maximum charging rate: 3C
Maximum continuous discharge: 12C / 60A
Maximum cell temperature during discharge: 80°C, with temperature cut-off protection
These specifications provide strong high-power output capability.
Physical and environmental specifications:
Height: 70.80 ± 0.2mm
Diameter: 21.40 ± 0.2mm
Weight: ≤70g
AC internal resistance at 1000Hz: ≤5mΩ
Charging temperature: -10°C to 50°C
Discharging temperature: -40°C to 60°C
Humidity: 0–70% RH, non-condensing
Storage temperature requirements vary according to storage duration. For long-term storage of up to 12 months, the recommended temperature range is -20°C to 25°C.
Internal Resistance Test
The internal resistance was measured using a Hantai HBT4561A internal resistance tester at both full and empty states.
The manufacturer’s specified internal resistance is ≤5mΩ.
The actual test results were:
At 4.2V full charge: 1.93mΩ
At 2.5V discharge state: 2.25mΩ
The measured resistance was therefore significantly lower than the specified maximum value.
Charging Test
The cell was tested at multiple charging rates from 0.2C to 3C.
0.2C Charging
Charging current: 1000mA
Total charging time: approximately 5 hours 32 minutes
20%: 1h 11min
50%: 2h 47min
80%: 4h 16min
100%: 5h 32min
0.5C Charging
Charging current: 2500mA
Total charging time: approximately 2 hours 27 minutes
20%: 28min
50%: 1h 06min
80%: 1h 42min
100%: 2h 27min
1C Charging
Charging current: 5000mA
Total charging time: approximately 1 hour 26 minutes
20%: 13min
50%: 33min
80%: 51min
100%: 1h 26min
2C Charging
Charging current: 10000mA
Total charging time: approximately 50 minutes
20%: 6min
50%: 16min
80%: 25min
100%: 50min
3C Charging
Charging current: 15000mA
Total charging time: approximately 37 minutes
20%: 4min
50%: 10min
80%: 16min
100%: 37min
The cell was also tested at 3C / 15A and successfully passed the ChargerLAB 1050 fast-charging test.
The ChargerLAB 1050 test uses 50% charging within 10 minutes as the benchmark for evaluating fast-charging performance.
Discharge Test
Discharge tests were conducted at 25 ± 2°C using constant-current discharge.
0.2C Discharge
Current: 1000mA
Average voltage: 3.59V
Capacity: 5198mAh
Energy: 18.67Wh
Discharge time: approximately 5h 11min
0.5C Discharge
Current: 2500mA
Average voltage: 3.59V
Capacity: 5041mAh
Energy: 18.08Wh
Discharge time: approximately 2h
1C Discharge
Current: 5000mA
Average voltage: 3.56V
Capacity: 4985mAh
Energy: 17.77Wh
Discharge time: approximately 59min
3C Discharge
Current: 15000mA
Average voltage: 3.49V
Capacity: 5058mAh
Energy: 17.63Wh
Discharge time: approximately 20min
5C Discharge
Current: 25000mA
Average voltage: 3.43V
Capacity: 5126mAh
Energy: 17.58Wh
Discharge time: approximately 12min
8C Discharge
Current: 40000mA
Average voltage: 3.35V
Capacity: 5110mAh
Energy: 17.13Wh
Discharge time: approximately 7min
The test results show that the cell maintained more than 5000mAh capacity at most of the tested high discharge rates, demonstrating strong high-rate discharge performance.
Charging Temperature Test
The surface temperature was measured during charging at different rates.
Charging Rate Temperature
0.2C approx. 25.8°C
0.5C approx. 26.9°C
1C approx. 31.4°C
2C approx. 39.1°C
3C approx. 53°C
At 3C charging, the cell reached a surface temperature of approximately 53°C after 15 minutes.
Discharge Temperature Test
The surface temperature was also measured at different discharge rates.
Discharge Rate Temperature
0.2C approx. 25.1°C
0.5C approx. 26.1°C
1C approx. 31.5°C
3C approx. 52.2°C
5C approx. 72.2°C
8C approx. 88.2°C
Conclusion
Overall, the Yichuan New Energy INR21700-50PL full-tab cell demonstrated strong and balanced performance.
From a manufacturing perspective, the cell features a clean appearance, clear markings, and measured dimensions and weight that closely match the manufacturer’s specifications.
From an electrical performance perspective, the measured internal resistance was below 2mΩ, significantly lower than the specified maximum of 5mΩ, demonstrating the low-resistance advantage of the full-tab design.
The charging tests covered 0.2C to 3C, and the cell successfully passed the ChargerLAB 1050 fast-charging test at 3C / 15A.
The discharge tests covered low-rate to 8C high-rate discharge, with the measured capacity exceeding the nominal 5000mAh capacity at most tested rates.
Temperature testing showed moderate temperature rise under conventional charging and discharging conditions. Combined with the thermal-safety benefits of the LATP cathode coating, the cell demonstrates reliable overall performance.
Overall, the Yichuan INR21700-50PL combines high energy density, high-rate performance, and thermal stability, making it suitable for applications including high-power energy storage systems, power tools, high-power portable power supplies, and other demanding battery applications.
