1.Why do you need to test the internal resistance and open circuit voltage of a battery?
Testing the internal resistance and voltage of the battery is a quick and effective method to identify the battery’s conditions.
2.What are the test methods for battery internal resistance?
According to the different battery models established, there are two main methods: AC injection method and DC discharge method.
3.What is the basic principle of AC internal resistance method?
The AC internal resistance method is based on the battery impedance model to measure the vector impedance of battery.
4.What is the AC internal resistance?
It is the equivalent resistance of the battery impedance in the vector plane.
5.What are the differences between the AC test method and the DC discharge method for
battery internal resistance?
Because the two test methods are based on different models, there is not much contrast.
But both can be used to evaluate the performance of the battery. Generally, in the internal resistance test of the lithium battery, the AC test method is more common.
6.What is the test frequency used by the AC test method?
7.What equipment can be used to test the DC resistance of the battery?
Hope instrument’s DC electronic loads have the function of testing the DC internal resistance of the battery.
8.Does the eddy current effect on test accuracy?
Due to the eddy current effect of the AC signal, part of the current is bypassed, which results in a reduction in test accuracy.
9.Under what circumstances does eddy currents occur?
There is a metal plane near the loop plane 10cm formed by the test leads, or there is a metal substance in the loop.
10.Why is the use of four probe test method?
The two probe test is only suitable for impedance measurement at the Ω level. The internal resistance of the battery is generally at the mΩ level, and the four-terminal test can reach the impedance test at the μΩ level.