There are several equipments that need electrical energy to work. Some of them need the battery to be changed, others have cells or batteries that are rechargeable. An example of the use of a rechargeable battery is the automobile, because when we start the engine, the battery in it provides the energy necessary to activate the starter motor.
We can say that this process occurs because the electrical energy that drives the starter nothing it is more than the energy that is stored in chemical bonds and turned into energy electrical. After the engine starts running, another device called an alternator (or dynamo) starts to work, charging the car's battery.
Current enters through the positive pole of the battery
We can see in the figure above that instead of the electric current leaving the positive terminal of the battery, it enters through the positive pole. Thus, the chemical reactions occur in the opposite direction to that verified in the phase in which the battery was activating the starter.
We see that in this process the battery receives electrical energy, which is stored in chemical bonds, and does not supply electrical energy to the circuit. So we say that the car battery works as a receiver and not a generator while the car is running.
We can find this same process with cordless phones as well as cell phone batteries. Because when we are using these types of phones their batteries work as generators, as the current leaves the positive pole. But when their batteries run out, or better, run out, they are placed in appliances connected to electricity to be charged.
In this phase, they do not function as generators, but as receivers: current enters through the positive pole. There are batteries that cannot be recharged, as chemical reactions cannot take place in reverse. Rechargeable batteries are also called reversible generators.
When a reversible generator acts as a receiver, its electromotive force (E) is often called the force. electromotive, which is abbreviated by f.c.e.m. An electric motor receiving power from a generator is also a receiver.
By Domitiano Marques
Graduated in Physics
Brazil School Team
Source: Brazil School - https://brasilescola.uol.com.br/fisica/recarregando-baterias.htm
