The internal resistance of all batteries is the smaller the better, the smaller the internal resistance, the stronger the discharge capacity of large current, the more full the release of electric energy.
Any power supply more or less has a certain internal resistance, in order to improve the load capacity, we want the power supply internal resistance as small as possible.
In the figure above, resistance R is the internal resistance of automobile battery, RL is the load, which is in series with the internal resistance R, and the current flowing through R is equal to the load current. Assuming that the size of the r is kept constant, the greater the load current, the greater the current through the resistance r, the higher the voltage at the ends of the r, so add the load RL on both ends of the voltage is reduced, if the pressure drop on the internal resistance is too large, even lead to RL unable to obtain the rated working voltage and can't work normally, so we hope the battery internal resistance as small as possible, in order to drive the heavy load, No significant pressure drop occurs on the internal resistance.
The internal resistance of the battery will increase with the growth of the use of time, especially the fast scrapped battery, the internal resistance increases significantly, although the battery voltage is higher after full charge, but because the internal resistance becomes larger, a large current load, the internal resistance will produce a larger voltage drop, so that the voltage at both ends of the load is reduced.
