The discharge current is the current that an accumulator or battery can deliver over a certain period of time. The discharge current depends on the nominal capacity and the C coefficient, the state of charge, the internal resistance, the end-of-discharge voltage and the time curve of the discharge.
The discharge current is directly related to the C coefficient and the nominal capacity of rechargeable batteries. The C coefficient indicates the discharge time and the nominal capacity indicates the discharge current that can be drawn during this time. It should be noted, however, that the efficiency of the discharge can decrease slightly with increasing current, depending on the battery design. This means that a battery with a nominal capacity of 1 ampere-hour( Ah) will not deliver 1 ampere (A) for one hour, but slightly less.
It is important to note the discharge pattern, as certain batteries are better suited for constant low current discharge, while others are better suited for short duration high current discharge or constantly changing current discharge. The C-coefficient or C-factor does some justice to this distinction, because it indicates the charge current or discharge current of a battery in relation to its rated capacity. The amount of time it takes to discharge is equal to the discharge time. The C value indicates the maximum current in relation to the battery capacity. For example, a battery with a C coefficient of 2C can deliver a discharge current of 2 A for one hour, or a discharge current of 1 A for two hours.
The discharge current can be drawn until the final discharge voltage is reached. This applies equally to rechargeable batteries for mobile devices and to power batteries for electric vehicles. To prevent damage caused by excessive discharge currents, certain batteries, such as lithium-ion batteries, have excessive discharge currents limited electronically.