Why test for battery internal resistance?
Publish time : 2022-11-23
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Battery voltage, current, and temperature are important operating parameters of the battery, but they cannot reflect the internal status of the battery Internal resistance, as the most effective and convenient performance parameter for the battery recognized internationally, can reflect the deterioration degree, capacity state and other performance indicators of the battery, but these indicators are unable to reflect other operating parameters.
The main failure mode of the battery: water loss, negative plate vulcanization, positive plate corrosion and thermal runaway direct influence the capacity of the battery decreases and the internal resistance increases, which is the main reason for the increase of the battery internal resistance.
As the capacity of the battery decreases, the internal resistance of the battery increases. The larger the capacity of the battery, the smaller the internal resistance, and with the increase of the deterioration of the battery, the internal resistance of the battery will also be significantly increased，Therefore, the internal resistance of the battery has a close relationship with its capacity: the increase of the internal resistance of the battery is an important sign of the deterioration of the battery performance.
Research presented at the International Telecommunication Power Conference showed that if the internal resistance of a battery exceeds the normal value by 25%, the capacity has been reduced to about 80% of its nominal capacity，If the internal resistance of a battery exceeds 50% of the normal value, the capacity of the battery is reduced to less than 80% of the nominal capacity. Replace the battery in time.
Batteries are used in series at most sites, and the performance of a single battery directly affects the performance of the battery group. A poor battery in a battery pack will accelerate the deterioration of other batteries in series with it. Therefore, the monitoring of single battery is a necessary condition to ensure the capacity and service life of the battery group.
By testing the internal resistance of each battery in the battery pack, the performance state of each battery in the battery pack can be accurately mastered. At the same time, it is of great significance to ensure the stability of battery power supply and prolong the service life of battery set.
