How Does a Battery Work?

Batteries produce electrons within their containers to power many different types of electrical devices. Because the flow of electrons through a device is important in powering it, a battery has to somehow produce a seemingly endless supply of them to continually power the device.

Within the actual container of a battery, typically a metal cylindrical shell, there are various chemicals. These chemicals react with one another and through what’s known as an electrochemical reaction, these chemicals release electrons to the outside.

The Components

A battery consists of three main components. First of all, every battery must have a positive and negative terminal. This is not to say that each one is charged a certain way, it just means that as electrons flow out, the “potential” charge of the other terminal is lower than the one expelling electrons. These two terminals complete a circuit. If you were to connect a wire between the negative terminal of a battery and the positive terminal, electrons would flow from the negative end of the battery and go back into the battery through a positive end. This is how batteries stay good for quite a while.

Practical Application

When you put a battery into something like a television remote, every time a button is pressed on the remote, current is pulled from the battery through the negative terminal. The electrons flow through the remote and their power is harnessed to utilize the button. Then, when the electrons are finished doing their job, they’re passed back through another wire and go back into the battery through the positive terminal. Because electrons and matter can’t just disappear, completing this circuit is essential to prevent electrons from building up inside of your television remote or any other device.

Over time, electrons are lost to the outside world. Because of wire resistance and contact with other things, the percentage of electrons that make it back into the battery isn’t quite 100%. This is why batteries lose their charge after a while. Once electrons make it back into a battery through the positively charged terminal of a battery, they make their way back into the atoms of the chemicals within the battery. This allows the battery to continue performing its function and produce more chemical reactions.

The Actual Chemical Reaction

So, how exactly do batteries produce electrons through chemical reactions? There are many different types of batteries out there all operating under different principles, but for this example we’re going to take a look at car batteries. The batteries you buy in the store, like Duracell or Rayovac, use less volatile chemicals in their batteries as for household use, using the same thing as a car battery would be dangerous. Typically, standard AA or AAA batteries use a zinc-carbon reaction.

Car batteries operate under a lead-acid reaction. Within a car battery’s cell, there are two plates. One plate is made of lead and the other is made of lead dioxide. Both plates are immersed in a sulfuric acid liquid. The lead plate releases lead ions that combine with the sulfate ions produced by the sulfuric acid. These two combine to form lead sulfate and an electron. This new lead sulfate, along with other sulfate ions, hydrogen ions, and more lead dioxide make their way to the lead dioxide plate. On this plate, water, electrons, and lead sulfate build up. Once the battery discharges, all of the electrons leave the top plate and go out of the negative terminal of the battery, leaving lead sulfate and water behind. These then disassociate and begin the entire process again when electrons come back into the battery.

Zinc is by far the most popular choice of chemical to put into a battery, and apart from car batteries, it’s in about 90% of the batteries you come into contact with on a daily basis.

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