Will excessive internal resistance of the battery affect its lifespan?

The answer is yes. The internal resistance of the battery is one of the important indicators to measure its health status. Excessive internal resistance will directly affect the discharge performance and charging efficiency of the battery, thereby shortening its service life. The following are several main factors that affect the internal resistance of the battery:

1) Use time
As the battery is used for a longer time, problems such as electrolyte dehydration, corrosion of the plates and connecting strips, sulfation of the plates, deformation of the plates, and shedding of active substances will gradually appear. These factors will cause the battery capacity to decrease, the internal resistance to gradually increase, and in severe cases, it may even fail to work normally.

2) Charge and structural design
The different physical properties of the battery at the time of leaving the factory, such as the depth of the electrolyte, the thickness of the active material on the electrode surface, and the porosity of the electrode, will lead to differences in its internal resistance, thereby affecting its actual charge storage capacity. Batteries with optimized structures usually have lower internal resistance and more stable performance.

3) Ambient temperature
The influence of temperature on internal resistance is also very significant. The increase in ambient temperature will accelerate the diffusion rate of the reactants, promote charge transfer and electrode reaction processes, and reduce the internal resistance of the battery; in a low temperature environment, these processes become slow, and the internal resistance increases, which in turn affects the performance of the battery.

4) Model and manufacturing process
Batteries of different manufacturers, types and models have different internal resistances due to differences in electrode materials, electrolyte formulations, diaphragm types and structural designs. Excellent materials and precise assembly processes help to reduce the initial internal resistance and improve the overall performance of the battery.

5) Influence of measurement frequency
The internal resistance test of most batteries currently actually measures its impedance, including resistance and capacitive reactance. Since the capacitive reactance is related to the test signal frequency, if the capacitive reactance is not reasonably analyzed and processed, the measured internal resistance data will not truly reflect the electrical state of the battery. Therefore, a scientific measurement method should be based on the phase relationship between current and voltage to eliminate the influence of capacitive reactance, so that a consistent internal resistance value can be obtained at different frequencies.

6) Measuring current and timing
During the internal resistance measurement process, the current magnitude and duration of the applied signal will also affect the test results. When a larger test current is used, the polarization phenomenon will be more obvious, resulting in measurement errors. To ensure the objectivity of the measurement, it is recommended to use a smaller signal current for testing. For example, when the measured current does not exceed 0.05 times the rated discharge rate of the battery for 10 hours (i.e. ≤0.05C10), the internal resistance data obtained is more representative and accurate.

About the nominal voltage of the battery

People often say that the voltage of a battery is 12V. The "12V" here refers to its nominal voltage, also known as the nominal potential. The single cell voltage of a standard lead-acid battery is 2V, and usually 6 single cells are connected in series to form a 12V battery. Battery packs used in electric vehicles and power systems are often composed of 2 to 5 12V batteries connected in series to form a 24V, 36V, 48V or even 60V battery pack. These values ​​reflect the theoretical voltage of the battery pack under standard conditions, which is determined by the chemical materials and structure used.