Normal discharge can still be achieved at -40℃, WORWORF 18650 32ML cell evaluation
2023-12-20
Introduction
Previously, the charging head network introduced the R&D brand of Shenzhen Root Giant Technology Co., LTD. - WORWORF. WORWORF focuses on low-temperature batteries, which solve the pain point that people in cold areas often cannot use electronic products because of low temperatures, and has developed a variety of specifications to meet the size required by each equipment, as well as a variety of capacities, which can flexibly combine a variety of large-capacity battery packs.
This time, we will bring you the test of the 18650 32ML battery cell. Its nominal capacity is 3200mAh, which is the largest capacity in the series of batteries. It has also passed a variety of safety standards, as well as high-safety structural design, precise power-off, Pressure relief device; the charging head network will conduct tests from three aspects: charge and discharge, internal resistance and temperature to comprehensively analyze the performance of this battery core. Let’s take a look together.
Appearance introduction
As usual, let’s first take a look at the appearance of this battery cell.
The WORWORF18650 32ML battery cell is a cylindrical design with a gray battery core film color, and the film color can be adjusted according to requirements to meet the diverse needs of customers.
The other side of the WORWORF18650 32ML battery cell has a cell printing code:
"WWF 18650 32ML"
Rated capacity: 3200mAh@0.2C;
Nominal voltage: 3.6V; Nominal energy: 11.52Wh;
AC internal resistance: ≤35mΩ
"WWF 18650 32ML"
Rated capacity: 3200mAh@0.2C;
Nominal voltage: 3.6V; Nominal energy: 11.52Wh;
AC internal resistance: ≤35mΩ
The negative contact surface of WORWORF18650 32ML battery cell is made of alloy metal and treated with anodizing process, making it durable and anti-corrosion.
The positive contact surface of WORWORF18650 32ML battery cell is still made of alloy, and the wafers are also connected using four solder points.
Measured using a plastic caliper, the cylindrical height of WORWORF18650 32ML battery cell is approximately 65.2mm.
WORWORF18650 32ML battery column diameter is approximately 18.1mm.
WORWORF18650 32ML battery cell weighs approximately 44.8g.
WORWORF18650 32ML battery cell is relatively small in the hands of adult men and is of standard 18650 size.
Charge and discharge test
After looking at the appearance, let’s get to the point; below we will conduct charge and discharge tests at 0.2C, 0.5C and 1C rates.
Charging test
The charging test will perform constant current and constant voltage charging at 0.2C, 0.5C and 1C rates, and the total time consumption will be calculated.
0.2C charging
Draw a line chart, set the current to 640mA, and 0.2C to charge the WORWORF 18650 32ML battery. The charging cut-off voltage is 4.2V, which takes about 5 hours and 10 minutes.
0.5C charging
Draw a line chart, set the current to 1600mA, 0.5C to charge the WORWORF 18650 32ML battery, the charging cut-off voltage is 4.2V, and it takes about 2 hours and 28 minutes.
1C charging
Draw a line chart, set the current to 3200mA, 0.2C to charge the WORWORF 18650 32ML battery, the charging cut-off voltage is 4.2V, and it takes about 1 hour and 39 minutes.
The test data is drawn into a line chart. In the charging test, it took 5 hours and 10 minutes to fully charge at 0.2C, 2 hours and 28 minutes at 0.5C, and 1 hour and 39 minutes at 1C.
Discharge test
During the discharge test phase, constant current discharge will be used, and the total time taken and the discharged capacity and energy values will be calculated.
0.2C discharge
Draw a line chart, set the current to 640mA, 0.2C to discharge the WORWORF 18650 32ML battery cell, the average voltage is 3.63V, and the cut-off voltage is 2.5V. It takes about 9 hours and 41 minutes, the released capacity is 3104mAh, and the released energy is 11.25 Wh.
0.5C discharge
Draw a line graph, set the current to 1600mA, 0.2C to discharge the Volvaf 18650 32ML battery cell, the average voltage is 3.55V, and the cut-off voltage is 2.5V. It takes about 1 hour and 54 minutes, the released capacity is 3055mAh, and the released energy is 10.86 Wh.
1C discharge
Draw a line chart, set the current to 3200mA, 0.2C to discharge the Wovac 18650 32ML battery cell, the average voltage is 3.49V, and the cut-off voltage is 2.5V. It takes about 56 minutes, and the released capacity is 3033mAh, and the released energy is 10.57Wh.
Summarizing the test data into a table, we can see the gap between the discharge tests of the battery cells at three rates. The shortest discharge time is 1C discharge, with a discharge time of about 56 minutes. The longest discharge time is 0.2C discharge, and the discharge time is about 9 hours and 41 minutes.
The test data is summarized into a histogram. In the discharge test, the overall discharge energy is between 10.57-11.25Wh; the overall difference is not large. The highest discharge energy is the 0.2C discharge gear, and the discharge energy reaches 11.25Wh, which is basically the nominal value. Energy; the lowest discharge energy is the 1C discharge gear, with a discharge energy of 10.57Wh.
Let's take a look at the difference in capacity released by each gear. Draw the data on a curve chart. You can see that the 0.2C discharge gear has a capacity of 3104mAh, and the lowest capacity is the 1C discharge gear, which has a capacity of 3033mAh.
Internal resistance test
In the internal resistance test part, the charging head network will use internal resistance testing equipment to test the fully charged internal resistance and empty powered internal resistance respectively.
Summarizing the test data into a table, you can see that the internal resistance voltage of full power is 4.2V, the internal resistance voltage of empty power is 2.5V, and the nominal internal resistance of WORWORF 18650 32ML battery is ≤35mΩ.
Drawing a histogram, you can see that the internal resistance of 4.2V full power is 24.97mΩ, and the internal resistance of 2.5V empty power is 25.1mΩ. Neither exceeds the nominal internal resistance, and the internal resistance difference between full power and empty power is small. perform well.
Temperature test
In the temperature test part, the charging head network will measure the temperature after 30 minutes at each charge and discharge rate.
Charging temperature test
0.2C charging
Charge the WORWORF 18650 32ML battery at a rate of 0.2C for 30 minutes, and the maximum surface temperature is about 23.8°C.
0.5C charging
Charge the WORWORF 18650 32ML battery at a rate of 0.5C for 30 minutes, and the maximum surface temperature is about 27°C.
1C charging
When the WORWORF 18650 32ML battery was charged at a rate of 1C for 30 minutes, the maximum surface temperature was about 29.7°C.
Discharge temperature test
0.2C discharge
Discharge the WORWORF 18650 32ML battery at a rate of 0.2C for 30 minutes, and the maximum surface temperature is about 26°C.
0.5C discharge
The WORWORF 18650 32ML battery cell was discharged at a rate of 0.2C for 30 minutes, and the maximum surface temperature was about 30.8°C.
1C discharge
Discharge the WORWORF 18650 32ML battery at a rate of 1C for 30 minutes, and the maximum surface temperature is about 32.8°C.
Summary of charging head network
For this WORWORF 18650 32ML battery, the charging head network was tested at three rates of 0.2C, 0.5C and 1C. In terms of charging, charging at 1C rate can be completed in 1 hour and 39 minutes. In the discharge part, you can see 0.2 The C rate discharge discharge capacity is 3104mAh, which is close to the nominal capacity. The discharged energy is also the highest, reaching 11.25Wh.
Let’s take a look at the internal resistance and temperature performance. The internal resistance value does not exceed the nominal internal resistance in both empty and fully charged states, and is both around 24-25mΩ. In terms of temperature, after 30 minutes of charging and discharging in three groups of different rates. Test temperature, the temperature is in the range of 23-32℃, and the heat generation is small.
Overall, this WORWORF 18650 32ML battery cell has shown excellent performance in terms of charge and discharge capacity, internal resistance and temperature performance. It supports 3C discharge at room temperature and can discharge at 0.2C at -40 degrees Celsius. , the capacity retention rate is greater than or equal to 70%, providing strong support for electronic products in extreme climates.
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