EVE Energy was among the first to adopt the full-tab (multi-tab) technology, pioneering the launch of a series of full-tab cells including the 20PL, 30PL, 40PL, and 50PL. Recently, our team acquired what can be described as a “performance powerhouse” – the INR21700-50PL. According to available information, this EVE 21700 full-tab cell supports a maximum continuous discharge current of 125A (25C), a pulse discharge of 180A (36C) for 2 seconds, and a maximum charge rate of 10A (2C). Its performance is exceptionally robust, with a typical capacity of 5000mAh and the ability to operate within a wide temperature range of -20°C to 60°C. Let’s take a closer look at how this cell performs in real-world tests.
Close-up of the current shipping 50PL silkscreen:
Model: INR21700-50PL
Nominal Energy: 18Wh
Nominal Capacity: 5000mAh
Nominal Voltage: 3.6V
Products with the EVE logo on the silkscreen are expected to be released around November 2025.
Charge Test
The charge test will be performed using the constant current-constant voltage (CC-CV) method, and the total duration will be recorded.
0.2C/0.5C/1C/2C Charge test
Discharge Test
The discharge test phase will be conducted using a constant current (CC) discharge method. The total duration, along with the released capacity and energy output values, will be recorded and analyzed.
Internal Resistance Test
For the internal resistance test, Battery Network used an internal resistance tester to measure both the fully charged and fully discharged internal resistance.
The voltage for a fully charged state is 4.2V, and for a fully discharged state, it’s 2.5V. EVE Lithium Energy’s INR21700-50PL cell has a nominal internal resistance of ≤5mΩ.
The measured internal resistance at 4.2V (fully charged) was 2.98mΩ, and at 2.5V (fully discharged) it was 3.05mΩ. The cell’s internal resistance shows little variation between these two voltage states and is significantly lower than the nominal specification, indicating excellent performance.
Temperature Test
Charge Temperature Test
- Charging the EVE INR21700-50PL cell at a 0.2C rate for 30 minutes resulted in a surface center temperature of approximately 26.5°C.
- Charging at a 0.5C rate for 30 minutes resulted in a surface center temperature of approximately 26.5°C.
- Charging at a 1C rate for 30 minutes resulted in a maximum surface temperature of approximately 33.4°C.
- Charging at a 2C rate for 30 minutes resulted in a maximum surface temperature of approximately 42°C.
Discharge Temperature Test
- Discharging the EVE INR21700-50PL cell at a 0.2C rate for 30 minutes resulted in a surface center temperature of approximately 26.6°C.
- Discharging at a 0.5C rate for 30 minutes resulted in a surface center temperature of approximately 26.5°C.
- Discharging at a 1C rate for 30 minutes resulted in a maximum surface temperature of approximately 31.8°C.
- Discharging at a 3C rate for 19 minutes resulted in a maximum surface temperature of approximately 52.6°C.
- Discharging at a 5C rate for 11 minutes resulted in a maximum surface temperature of approximately 65.6°C.
- Discharging at an 8C rate for 7 minutes resulted in a maximum surface temperature of approximately 82°C.
Summary
Based on this evaluation of the EVE INR21700-50PL full-tab cell, its fundamental specifications are outstanding. Its ultra-high discharge capability of 125A continuous and 180A instantaneous discharge undoubtedly positions it as a top-tier product among 21700 format cells. It also supports 10A (2C) fast charging. Benefiting from the full-tab structure, its internal resistance is controlled at around 3mΩ, and it can operate within a wide temperature range of -20°C to 60°C.
Regarding charge and discharge performance:
- Charging: At the standard 0.2C rate, the time to reach 4.2V was about 4 hours 49 minutes, with a full complete charge (including tail current) taking about 5 hours 7 minutes. Under 2C fast charging, the time to reach 4.2V was about 38 minutes, with a full complete charge taking about 1 hour 4 minutes.
- Discharging: The discharged capacity at various rates was all above 4800mAh. The highest capacity was 4963mAh at the 0.2C discharge rate, while the lowest was 4818mAh at the 5C discharge rate. The overall discharge energy ranged between 16.15 Wh and 17.89 Wh.
In terms of temperature performance, the cell excelled during charging, with the maximum temperature reaching only about 42°C even at the highest charge rate. During discharge, the temperature increased with the discharge rate, peaking at around 82°C. Temperatures remained within acceptable standards for rates up to 8C. For internal resistance, the EVE INR21700-50PL cell, with a nominal specification of ≤5mΩ, measured 2.98mΩ at 4.2V (full) and 3.05mΩ at 2.5V (empty). The minimal difference between these states and the significantly lower-than-specified values demonstrate excellent performance.
Overall, the EVE INR21700-50PL full-tab cell, with its trio of high-performance characteristics – ~3mΩ internal resistance, 125A continuous discharge, and 10A fast charging – sets a new benchmark for 21700 cell performance. Its full-tab technology not only provides an ultimate solution for UAVs, offering “high power + long endurance + fast response,” but is also poised to drive technological iteration in other high-rate application fields such as power tools and energy storage systems.
