How does a battery work?

Batteries are self-contained power packs that can produce electrical energy when required. The energy is stored in the form of mechanical energy in the battery, and through a few chemical reactions taking place, it is then converted into electrical energy. The mechanical energy in the battery can last for up to a few years, which is why batteries are the perfect example of portable power.

It seems amazing as to how batteries are making our life easier, and this compels us to wonder how does a battery works. It’s time that we solve the mystery and let you know all about the working of a battery.

The main parts of a battery

The power unit or the system inside the battery as a whole is known as a cell. A cell consists of three major components. Two of them are electrodes (electrical terminals) known as Cathode and Anode, and between the two terminals, there is a chemical known as Electrolyte. For the safety and convenience of consumers, the battery is covered with a plastic outer case.

Moreover, there are two electric terminals outside the cell marked plus (+) and minus (-). These terminals are connected to the cathode and anode inside the cell, which is the difference between a cell and a battery. A cell usually consists of only two electrical terminals. It is a complete system within itself, while a battery may have two or more cells connected together in order to get a sum of their energy.

The cathode and anode in a battery are always made from two different metals. It is because one of the electrodes, generally the cathode, is made from a material that tends to give up electrons. Whereas the anode is made up of a conducting material that always tends to receive electrons. This difference between the two electrodes makes the process of current flow work. If no difference occurred between the two materials, there would be no transfer of electrons, and the cell would not work.

How does a battery work?

The working principle of a battery is quite simple. The positive terminal of the battery is the cathode. While the negative terminal is known as an anode. It is important to understand that these terminals or cathodes work differently than they would in the process of electrolysis. In electrolysis, the cathode acts as a negative terminal while the anode is the positive terminal. But in the process of converting mechanical energy into electrical energy in a battery, the roles of the two electrodes are switched around.

There is a chemical electrolyte present between the two electrodes. In an ordinary battery, the electrolyte is a dry powder in most cases, but it can also be a liquid as long as it serves the purpose. After the battery is connected to an electronic device such as a lamp or a bulb and then switched on, the chemical process begins.

As an effect of one of the reactions taking place in the cell, positive ions and electrons are generated at the negative electrode. The positive ions produced then flow into the electrolyte. However, the electrons move towards the positive electrode through an outer circuit. The electrons on the way light up the electronic device that you have connected to the circuit.

At the positive electrode, a separate chemical reaction takes place. The incoming electrons from the negative electrode are combined with the ions (the ions are taken out of the electrolyte), and in this way, the circuit is completed.

The current flow is a result of these two chemical reactions going on in the cell simultaneously. However, the two reactions may depend upon the material of the electrodes and the electrolyte, but the principle remains the same. The principle is that electrons flow through the outer circuit while the ions react with electrolyte and then complete the circuit.

The fact that the electrons going towards the positive electrode through an outer circuit and not directly through the electrolysis may seem a little confusing, but there is a logic behind this process. Because of the composition and the chemistry of the electrolyte, the electrons cannot flow through it quickly.

Therefore, it prevents the electrons from going towards the positive electrode and acts as a barrier. Because of this, the easiest way that the electrons can get to the positive electrons is through the external circuit.

When is a battery considered flat?

Batteries do have a long life, but obviously, they cannot go on forever. After being used for a long time, the batteries lose their ability to convert mechanical energy into electrical energy. As it is used for longer, the chemicals that were once present in the battery gradually convert into other chemicals, and the battery’s ability to make electrical energy gradually decreases.

Consequently, the voltage of the battery decreases, and the battery is then considered flat, unable to produce electrical energy.


Batteries have become an essential component of our daily lives. There are various applications that need battery supply, and for that reason, it is crucial for you to know how does a battery works. Thoroughly reading this article will provide you enough information on the topic, and you will be able to identify and solve minor problems yourself. Knowing how a battery works will also allow you to use it proficiently and effectively.