Battery Encyclopedia


Is the internal resistance of the battery better with a larger value, or is it better with a smaller value?

The smaller the internal resistance of all batteries, the better. The smaller the internal resistance, the stronger the high current discharge ability, and the more fully the electrical energy is released. Any power supply has a certain degree of internal resistance, and in order to improve its load-bearing capacity, we hope that the internal resistance of the power supply is as small as possible. The resistance r in the above figure represents the internal resistance of the car battery, RL represents the load, and it is in series with the internal resistance r of the battery. The current flowing through r is equal to the load current. Assuming the size of r remains unchanged, the larger the load current, the greater the current flowing through the internal resistance r, and the higher the voltage at both ends of r, resulting in a decrease in the voltage applied at both ends of the load RL. If the voltage drop on the internal resistance is too large, it may even result in the RL not being able to obtain the rated working voltage and not working properly. Therefore, we hope that the internal resistance of the battery is as small as possible, so that there will be no significant voltage drop on the internal resistance when driving heavy loads. The internal resistance of a battery will increase with usage time, especially for batteries that are about to be scrapped. The internal resistance significantly increases. Although the battery voltage is high after being fully charged, the internal resistance becomes larger. Once a high current load is connected, a significant voltage drop will occur on the internal resistance, resulting in a decrease in the voltage at both ends of the load.

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