What is battery internal resistance? It refers to the resistance of current flowing through the battery when it is working. It consists of ohmic resistance and polarization resistance. The large internal resistance of the battery will lead to the decrease of the working voltage and the shortening of the discharge time. The internal resistance is mainly affected by the material, manufacturing process and structure of the battery. It is an important parameter to measure battery performance. Note: the internal resistance in charge state is generally taken as the standard. The internal resistance of the battery should be measured by a special internal resistance meter instead of the ohm range of a multimeter.