Lithium battery capacity test explanation

Capacity is the core parameter of lithium batteries. Lithium battery manufacturers generally have special equipment for testing to ensure the quality of the products shipped. For ordinary users, how to know whether the capacity of their newly purchased lithium battery is qualified?

Here is a simple test method: the multimeter test method.

An example of a 1000mAh lithium battery (in addition to a lithium battery and a multimeter, a charger is also required)

First of all, we must theoretically understand the voltage values of lithium batteries:

1. Charge termination voltage: It is also the no-load voltage, that is, the highest voltage when not working, generally 4.2V.

2. Working/nominal voltage: It is also the load voltage. The voltage during normal operation is generally 3.7V.

3. Discharge termination voltage: that is, the voltage at which the battery cannot work, with different designs of 3V and 2.75v.

Start the test, first charge the battery with the charger, the full voltage is 4.2V, then use the multimeter as a constant current load, discharge at 0.2C (1000×0.2=200mA), set the multimeter discharge voltage to 3V, if discharge A time of 5 hours means that the battery is qualified. Today's lithium batteries can generally discharge to 2.75V, which is 80% as the discharge depth of the previous 3V termination voltage, but can be put into 8 hours, indicating that the power of the lithium battery has increased.

0.2C is an international standard test method. In practice, the 0.5C test is usually used. In this case, the multimeter is set to a constant current load of 500mA, and it can take more than two hours to reach the 3V voltage.

The above mentioned pass qualification is relative to the nominal capacity. The nominal capacity = discharge current × discharge time. If the above discharge time is not enough, it indicates that the capacity marked by the lithium battery is not enough 1000mAh, which is a kind of capacity virtual standard behavior, which is a kind of deception to the consumer.

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