Lithium battery capacity tester technical principle and application scenarios

The core working principle of the lithium Battery Capacity Tester is based on the precise monitoring and data recording of the battery charging and discharging process. During the discharge phase, the tester draws current from the battery at a stable current, while closely monitoring and recording the discharge time and changes in the battery voltage. According to the power calculation formula in physics Q = I × t (where Q represents the power in coulombs; I represents the current in amperes; t represents the time in seconds), since the battery capacity is usually measured in milliampere hours (mAh), the battery capacity value can be obtained by multiplying the discharge current (converted to milliamperes) by the discharge time (converted to hours).

In order to ensure the accuracy of the measurement, a series of precise circuit modules are often integrated into the tester. Taking the common microcontroller-based tester as an example, it is generally equipped with a high-precision A/D conversion chip to convert the battery's analog voltage and current signals into digital signals for processing by the microcontroller. A/D sampling chips like PCF8591 have 4 analog input channels, which can accurately collect the battery voltage and the voltage signal converted by the current sensor. At the same time, a special current detection chip, such as ACS712, is also used, which can detect DC current within a certain range and convert the current into a proportional voltage value through the internal Hall device, greatly improving the accuracy and reliability of current detection.

How-to Guide

Preparation

Before using the lithium battery capacity tester, first make sure that the tester is in normal working condition. Check whether the appearance of the tester is damaged and whether the connection ports are loose. Then, select the appropriate test mode and parameter settings according to the type and specifications of the battery to be tested. For example, if the tester is a lithium-ion battery, it is necessary to set the battery type of the tester to lithium-ion battery, and reasonably set the discharge current, cut-off voltage and other parameters according to the nominal capacity and voltage range of the battery. At the same time, prepare the battery to be tested and ensure that the battery surface is clean and has no obvious damage or deformation.

Connecting the battery and testing

Correctly connect the positive and negative output lines of the lithium battery capacity tester to the positive and negative poles of the battery to be tested. When connecting, pay attention to the polarity not to be reversed, otherwise the tester and battery may be damaged. After the connection is completed, the tester usually emits a prompt tone or displays a successful connection message on the display. At this time, press the start button of the tester, and the tester will start to charge and discharge the battery according to the preset parameters. During the test, pay close attention to the various data displayed on the tester display, such as voltage, current, discharge time, capacity, etc., to ensure that the test process is normal. If the data is abnormal or the tester has an alarm message, the test should be stopped immediately and the cause should be checked.

Result reading and analysis

When the test is completed, the tester will directly display the battery capacity test results on the display. Some testers will also display the battery's charge and discharge curve, internal resistance and other related parameters at the same time. When reading the results, pay attention to the conversion of units to ensure that the obtained capacity value is accurate. For the analysis of the test results, if the battery capacity is not much different from the nominal capacity, it means that the battery performance is good; if the capacity is significantly lower than the nominal capacity, it indicates that the battery may have a capacity attenuation problem, and it is necessary to further check the battery's usage history, charge and discharge habits and other factors to determine whether the battery needs to be replaced or repaired. At the same time, other parameters provided by the tester, such as the shape of the charge and discharge curve, the size of the internal resistance, etc., can also be combined to comprehensively evaluate the health of the battery.