Battery, do you know how does it work?

Batteries are everywhere. The modern world is dependent on these portable sources of energy, which are found in everything from mobile devices to hearing aids to cars. 

But despite their prevalence in people's daily lives, batteries often go overlooked. Think about it: Do you really know how a battery works? Could you explain it to someone else?

What is Battery made of?

Batteries contain three basic parts: electrodes, an electrolyte and a separator. There are two electrodes in every battery. Both are made of conductive materials but serve different roles. One electrode is cathode which connects to the positive end of the battery and is where the electrical current leaves (or electrons enter) the battery during discharge, which is when the battery is being used to power something. The other electrode, known as the anode, connects to the negative end of the battery and is where the electrical current enters (or electrons leave) the battery during discharge.


Between these electrodes, as well as inside them, is the electrolyte. This is a liquid or gel-like substance that contains electrically charged particles, or ions. The ions combine with the materials that make up the electrodes, producing chemical reactions that allow a battery to generate an electric current.

The final part of the battery is separator which is straight forward. The separator's role is to keep the anode and the cathode separated from each other inside the battery. Without a separator, the two electrodes would come into contact, which would create a short circuit and prevent the battery from working properly.

How does a Battery work?

To envision how a battery works, picture yourself putting alkaline batteries, like double AAs, into a flashlight. When you put those batteries into the flashlight and then turn it on, what you're really doing is completing a circuit. The stored chemical energy in the battery converts to electrical energy, which travels out of the battery and into the base of the flashlight's bulb, causing it to light up. Then, the electric current re-enters the battery, but at the opposite end from where it came out originally.

All parts of the battery work together to make the flashlight light up. The electrodes in the battery contain atoms of certain conducting materials. For instance, in an alkaline battery, the anode is typically made of zinc, and manganese dioxide acts as the cathode. And the electrolyte between and inside those electrodes contains ions. When these ions meet up with the electrodes' atoms, certain electrochemical reactions take place between the ions and the electrodes' atoms.

The series of chemical reactions that occurs in the electrodes are collectively known as oxidation-reduction (redox) reactions. In a battery, the cathode is known as the oxidizing agent because it accepts electrons from the anode. The anode is known as the reducing agent, because it loses electrons.  

Ultimately, these reactions result in the flow of ions between the anode and the cathode, as well as the freeing of electrons from the atoms of the electrode.

These free electrons congregate inside the anode (the bottom, flat part of an alkaline battery). As a result, the two electrodes have different charges: The anode becomes negatively charged as electrons are released, and the cathode becomes positively charged as electrons (which are negatively charged) are consumed. This difference in charge causes the electrons to want to move toward the positively charged cathode. However, they don't have a way to get there inside the battery because the separator prevents them from doing so.

When you flick the switch on your flashlight, all that changes. The electrons now have a path to get to the cathode. But first, they must pass through the base of your flashlight's bulb. The circuit is completed when the electric current re-enters the battery through the top of the battery at the cathode.

If you liked this post, follow my blog for more technology reviews and share it on your favorite social media. If you have any inputs/queries post it in the comments, thank you.