Why we need to test battery internal resistance？
Publish time : 2022-07-22
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Battery voltage, current and temperature are important operating parameters of the battery.However, it cannot reflect the internal state of the battery。Internal resistance is currently internationally recognized as the most effective and convenient performance parameter for battery measurement. It can reflect the performance indicators such as the deterioration degree and capacity status of the battery，And these indicators are not reflected by other operating parameters.
The main failure mode of the battery（Including the direct effects of battery water loss, negative plate vulcanization, positive plate corrosion and thermal runaway, the capacity of the battery decreases and the internal resistance increases）is the main cause of the increase in the internal resistance of the battery.
As the capacity state of the battery decreases, the internal resistance of the battery will increase. The larger the battery capacity, the smaller the internal resistance reflected. At the same time, with the increase of the deterioration degree of the battery, the internal resistance of the battery will also increase significantly。Therefore, the increase of the internal resistance of the battery is an important sign of the deterioration of the battery performance.
The research results of the International Telecom Power Annual Conference show that if the internal resistance of the battery exceeds 25% of the normal value, the capacity has been reduced to about 80% of its nominal capacity，If the internal resistance of the battery exceeds 50% of the normal value, the capacity of the battery has been reduced to below 80% of its nominal capacity and needs to be replaced in time.
By testing the internal resistance of the single battery in the battery pack, the performance state of each single battery in the battery pack can be accurately grasped.At the same time, it is of great significance to ensure the stability of battery power supply and prolong the service life of the battery pack.
