Small size, long life, SAFD18500 DB battery review

The SAFD14500 DA battery cell, launched by Shenzhen Genju Technology Co., Ltd. (hereinafter referred to as "Genju"), is a self-developed brand of the SAFD. Its brand focuses on high rate, high capacity and small size batteries, and is mainly used in smart two-wheel travel power tools, smart homes, smart robots, drones, portable energy storage, medical equipment, industrial equipment and other fields.

This time, the charging head network introduces the SAFD18500 DB battery cell to you. Compared with the 14500 DA, the height remains unchanged, the diameter increases by about 4mm, and the capacity increases by 1400mAh. It can still be used normally at minus 20 degrees; it has also passed UN38.3, IEC62133, MSDS, CE certification, as well as high-safety structural design, precise power-off and pressure relief devices. The following charging head network will comprehensively analyze the performance of this battery from the perspective of charging and discharging, internal resistance and temperature tests.

Appearance introduction

As usual, let's look at the appearance first.

The SAFD18500 DB battery cell is cylindrical in design and uses a green battery film color. The color of the film can be adjusted according to requirements to meet the diverse needs of customers.

The front of the SAFD18500 DB battery cell is sprayed with the battery code:

"SAFD18500 DA"

Rated capacity: 2300mAh@0.2C;

charge and discharge cut-off voltages are 4.2V/2.75V respectively;

nominal voltage: 3.6V;

nominal energy: 8.28Wh;

AC internal resistance: ≤55mΩ.

The negative contact surface of the SAFD18500DB battery cell is made of alloy metal material, anodized, and durable and corrosion-resistant.

The positive contact surface of the SAFD18500DB battery cell is still made of alloy material, and the disc uses four welding points for a more secure connection.

Using a plastic caliper, the cylindrical height of the SAFD18500DB battery cell is about 49.2mm.

Using a plastic caliper, the cylindrical diameter of the SAFD18500DB battery cell is about 18.2mm.

The SAFD18500DB battery cell is relatively small in the hands of an adult man.

The weight of the SAFD18500DB battery cell is about 33.9g.

Charge and discharge test

After looking at the appearance, let's get to the point; the following will be charged and discharged 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 calculate the total time consumed.

0.2C charging

Draw a line chart, set the current to 460mA, 0.2C to charge the SAFD18500DB battery cell, the charging cut-off voltage is 4.2V, and it takes 5 hours and 32 minutes.

0.5C charging

Draw a line graph, set the current to 1150mA, 0.5C is for SAFD18500DB battery charging, the charging cut-off voltage is 4.2V, and it takes 2 hours and 46 minutes.

1C charging

Draw a line graph, set the current to 2300mA, 1C is for SAFD18500DB battery charging, the charging cut-off voltage is 4.2V, and it takes 2 hours and 01 minutes.

Draw the test data into a line graph. In the charging test, 0.2C charging takes 5 hours and 32 minutes, 0.5C charging takes 2 hours and 48 minutes, and 1C charging takes 2 hours and 01 minutes.

Discharge test

In the discharge test phase, constant current discharge will be used to count its total time consumption and its discharged capacity and energy value.

0.2C discharge

Draw a line graph, set the current to 460mA, 0.2C discharge for SAFD18500DB battery, average voltage 3.59V, discharge to cut-off voltage 2.5V, take about 5 hours and 1 minute, discharge capacity 2309mAh, release energy 8.29Wh.

0.5C discharge

Draw a line graph, set the current to 1150mA, 0.2C discharge for SAFD18500DB battery, average voltage 3.53V, discharge to cut-off voltage 2.5V, take about 1 hour and 58 minutes, discharge capacity 2275mAh, release energy 8.04Wh.

1C discharge

Draw a line chart, set the current to 1150mA, 0.2C for SAFD18500DB battery cell discharge, average voltage 3.44V, discharge to cut-off voltage 2.5V, take about 58 minutes, discharge capacity 2244mAh, release energy 7.73Wh.

Summarize the test data into a table, it can be seen that the battery cell is discharged at three rates. The shortest discharge time is 1C discharge, which is about 58 minutes. The longest discharge time is 0.2C discharge, which is about 5 hours and 01 minutes.

Summarize the test data into a bar chart, the overall discharge energy in the discharge test is between 7.73-8.29Wh; the overall gap is not large, among which the highest discharge energy is 0.2C discharge gear, the discharge energy reaches 8.29Wh, exceeding the rated capacity; the lowest discharge energy is 1C discharge gear, the discharge energy is 7.73Wh.

Let's take a look at the difference in capacity released by each gear. By plotting the data into a curve, we can see that the 0.2C discharge gear releases a capacity of 2309mAh, which exceeds the rated capacity. The lowest discharge capacity is 2244mAh at the 1C discharge gear.

Internal resistance test

In the internal resistance test, the charging head network will use an internal resistance tester to test the full-charge internal resistance and the empty-charge internal resistance respectively.

The test data is summarized in a table. It can be seen that the full-charge internal resistance voltage is 4.2V, and the empty-charge internal resistance voltage is 2.5V. The nominal internal resistance of SAFD18500 DB battery cell is ≤55mΩ.

Drawing a bar chart, it can be seen that the 4.2V full-charge internal resistance is 46.78mΩ, and the 2.5V empty-charge internal resistance is 46.78mΩ. There is not much change between the full-charge and empty-charge internal resistances, and they do not exceed the nominal internal resistance, which is excellent.

Temperature test

In the temperature test, the charging head network will measure the temperature after 30 minutes of each charge and discharge rate.

Charging temperature test

0.2C charging

The SAFD18500 DB battery cell is charged at a rate of 0.2C for 30 minutes, and the maximum surface temperature is about 27.5℃.

0.5C charging

The SAFD18500 DB battery cell is charged at a rate of 0.5C for 30 minutes, and the maximum surface temperature is about 29℃.

1C charging

The SAFD18500 DB battery cell is charged at a rate of 1C for 30 minutes, and the maximum surface temperature is about 30.9℃.

Discharge temperature test

0.2C discharge

The SAFD18500 DB battery cell is discharged at a rate of 0.2C for 30 minutes, and the maximum surface temperature is about 26.5℃.

0.5C discharge

The SAFD18500 DB battery cell was discharged at a rate of 0.5C for 30 minutes, and the maximum surface temperature was about 28.2℃.

1C discharge

The SAFD18500 DB battery cell was discharged at a rate of 1C for 30 minutes, and the maximum surface temperature was about 25.6℃.

Summary of the charging head network

This SAFD18500 DB battery cell was tested by the charging head network at three rates: 0.2C, 0.5C and 1C. In terms of charging, the 1C rate charging can complete the charging in 2 hours and 01 minutes. In the discharge part, it can be seen that the 0.2C rate discharge discharge capacity is 2309mAh, which exceeds the nominal capacity, and the energy released is also the highest, reaching 8.29Wh.

Let's take a look at the internal resistance and temperature performance. The internal resistance values ​​​​did not exceed the nominal internal resistance in both empty and fully charged states, and were both around 46mΩ. The internal resistance in the two different states did not change much. In terms of temperature, the temperature was tested after 30 minutes of charge and discharge at three different rates. The temperature was in the range of 27-35℃, and the heat generation was relatively small. Overall, this SAFD18500 DB battery cell has excellent performance in terms of charge and discharge capabilities, internal resistance, and temperature performance. Its compact body can play a huge advantage in small electrical appliances such as electric toothbrushes and electric shavers, providing a high-quality choice for small and lightweight products.