A Brief Introduction to Battery Internal Resistance

Author: Polinovel    |    October 14, 2022
Battery Internal Resistance


With the use of batteries, the battery performance continues to decline, mainly in the form of capacity loss, internal resistance increase, etc. Do you know anything about battery internal resistance? What affects the internal resistance of the battery?

About Battery Internal Resistance

The internal resistance of the battery refers to the resistance of the current flowing through the battery when the battery is working, which includes ohmic internal resistance and polarization internal resistance.

The ohmic resistance is mainly composed of electrolyte resistance, current collector resistance, and transition resistance between the current collector and active mass. The polarization resistance refers to the internal resistance caused by the polarization of the positive and the negative electrodes during the electrochemical reaction.

What Affects The Internal Resistance of The Battery?

Battery internal resistance is not a fixed value. And it will be affected by many factors. Let’s take a look at the factors that affect the internal resistance of the battery.


The temperature has a great effect on internal resistance. The lower the temperature, the slower the ion transport inside the battery, and the greater the internal resistance of the battery.


The internal resistance varies when the battery is in different SOC. Generally, the internal resistance of the battery increases significantly at a deeper depth of discharge.

Charge Cut-off Voltage

The charge cut-off voltage has an effect on the internal resistance during the battery cycle. Too high or too low a charge cut-off voltage will increase the interface impedance of the electrode.

What’s more, during the battery cycle, the internal resistance of the battery increases with the depth of charge and discharge. The increase of the internal resistance is proportional to the strengthening of the depth of charge and discharge.

Final Thought

Internal resistance is one of the important indicators to evaluate the performance of batteries, so we should have a certain understanding of the internal resistance of batteries.

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