Battery capacity

Battery capacity is a measure of the charge that a battery can store. This capacity is typically measured in ampere hours (Ah) or milliampere hours (mAh), which are units of electric charge. The capacity of a battery determines how long it can provide power at a certain rate before it needs to be recharged.

Definition

The capacity of a battery is defined as the maximum amount of electric charge that can be extracted from it under certain conditions. It is typically measured in ampere hours (Ah) or milliampere hours (mAh), where 1 Ah = 1000 mAh. The capacity of a battery depends on several factors, including the chemical composition of the battery, the temperature, and the rate at which the charge is drawn from the battery.

Factors affecting battery capacity

Several factors can affect the capacity of a battery. These include:

• Chemical composition: The type of chemical reaction that occurs in a battery can affect its capacity. For example, lithium-ion batteries typically have a higher capacity than nickel-cadmium batteries.

• Temperature: The capacity of a battery can decrease at low temperatures. This is because the chemical reactions that produce electricity in a battery are less efficient at low temperatures.

• Discharge rate: The rate at which the charge is drawn from a battery can affect its capacity. If the discharge rate is high, the battery's capacity can be reduced.

• Age and usage: Over time, the capacity of a battery can decrease due to wear and tear and chemical degradation.

Measurement of battery capacity

The capacity of a battery is typically measured using a discharge test, where the battery is discharged at a constant current until it reaches a specified end voltage. The total charge that has been extracted from the battery is then calculated, giving the battery's capacity.

Battery capacity and energy storage

The capacity of a battery is a key factor in its ability to store energy. A battery with a high capacity can store more energy and can therefore provide power for a longer period of time before it needs to be recharged. This makes high-capacity batteries particularly useful in applications such as electric vehicles and renewable energy storage.