A battery is actually quite special. Thanks to this little metal thing, everything comes to life: light comes from your flashlight, you can make calls with your smartphone and you can play on your Playstation. But how did batteries ever come about and how do they work? You read it here.
The discovery of the battery
No joke: the very first precursor to the battery was a frog’s leg. In 1780, the Italian scientist Luigi Galvani discovered that a frog’s leg moved if you held a metal rod against it. His colleague Alessandro Volta made the link with the hook with which the frog’s leg was hung. He suspected that it was the different metals that reacted with each other and – with the frog as a conductor – caused the frog’s leg to contract. To test and prove his theory, Volta filled a bowl with saline and inserted one copper plate and one zinc plate into it. He connected both metal plates and got power. The first battery was born!
How does a battery work?
A battery consists of 3 parts: the negative terminal (-), the positive terminal (+), and an electrolyte. The negative terminal of the battery releases electrons. A flow of electrons is what we call ‘electricity. The positive terminal is on the other side of the battery. This part of the battery, as it were, receives the power and gives it to the device containing the battery. Between the minus pole and the plus pole is a compound called an electrolyte. This is a kind of gel that mainly consists of salts and acids. The electrolyte causes a chemical reaction (conduction) that allows the electricity to flow. Yes! Your flashlight lights up again, the remote control works again or the toy makes noise again!
In fact, we can say that batteries are small chemical factories. That is quite exciting, so we have to handle it safely and responsibly. Did you know that batteries used to have a paper casing? That was way too fragile and quickly leaked. As a result, you got rust in appliances and there were health risks. Nowadays, the outside of batteries is made of metal.
A battery contains all kinds of substances that are bad for the environment. That is why it is important not to throw empty batteries in the trash, but to hand them in. This can be done in the supermarket or hardware store, but perhaps also at your school (and if that is not the case yet, your school can register here for free)! We can then reuse the materials to make new products such as a bicycle, gutter, or cheese slicer.
Batteries inside out: this is how a battery is made
If you make a battery today, you don’t have to deal with frog legs, lemons, or cola. You can’t just make a modern battery at home. The metals contained in it are not intended for home use. Batteries are made in large quantities in a professional environment. Alkaline batteries are made today at a rate of over 1000 pieces per minute.
Making an ordinary alkaline battery starts with a thin, empty steel shell. Due to the contact with the manganese dioxide (positive electrode), this sleeve forms the plus side of the battery. First, you put a thick metal ring in the sleeve, which is made of manganese dioxide. Then follows a thin layer of paper soaked in the electrolyte – which takes over the role of the frog’s leg – so that the manganese dioxide does not come into direct contact with the next type of metal: a zinc paste (negative electrode). Finally, a cap goes on the battery that is in the zinc paste with a kind of needle. That cap is the negative side of the battery.
When you now connect the plus side (where the manganese ring is) and the minus side (which is in the zinc paste), you get a closed circle. Now the negative electrons are attracted to the positive ones, and that makes the device work.
Which metals are found in batteries?
There are many types of batteries, each with a different composition. The principle of the two different metals from the frog leg of Galvani and Volta is preserved.
For example, batteries consist of:
- the alkaline battery, carbon battery : zinc + manganese dioxide
- the classic car battery: lead + lead dioxide
- the li-ion: a collective name in which lithium is an active ingredient, but which, in combination with many other metals, can form the basis of a lithium battery.
- Ni Cd: nickel and cadmium
- Zinc air battery: Is a unique case. This battery contains only one active element. The air with which the zinc reacts surrounds the battery. That is why this battery is equipped with a sticker that covers the holes and that will let the necessary air through when it is removed. It is best to wait a few minutes after removing the sticker before using it.