Batteries? This is how they are made!
Batteries have become indispensable in our lives. Our smartphones, laptops, remote controls, watches, digital devices, cars, ... nearly all the devices we use wirelessly contain a battery. But what exactly is INSIDE a battery? And how are batteries made?
Frog legs, lemons, and cola
The very first precursor of the battery was a frog's leg.
What? How?
Yep, the Italian scientist Galvani discovered that a frog's leg moved when you held a metal rod against it. His colleague Volta made the connection with the hook by which the frog's leg was hung. He suspected that it was the different types of metals reacting 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 a saline solution and inserted one copper plate and one zinc plate. He connected both metal plates and generated electricity. The first battery was born!
A frog's leg is now not the most convenient conductor, so you can also perform this test to generate electricity using a lemon or a bit of cola. As long as the liquid contains salt or acid, and the two plates are made of different types of metal, you can probably generate a minimal amount of electrical current.
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Batteries inside out: how a battery is made
If you make a battery today, you don't have to work with frog legs, lemons, or cola. You also can't just make a modern battery at home. The metals contained in it are not intended for home use. Batteries are produced in large quantities in a professional environment. Alkaline batteries are now produced at a rate of more than 1000 pieces per minute.
Making a standard alkaline battery starts with a thin empty steel casing. This casing, by making contact with manganese dioxide (positive electrode), forms the positive side of the battery. First, you insert a thick metal ring made of manganese dioxide into the casing. Then follows a thin layer of paper soaked in electrolyte - taking over the role of the frog leg - so that the manganese dioxide does not directly come into contact with the next type of metal: a zinc paste (negative electrode). Finally, a cap is placed on the battery which has a kind of needle stuck into the zinc paste. This cap is the negative side of the battery.
When you now connect the positive side (where the manganese ring is) with the negative side (sitting in the zinc paste), you create a closed circuit. Now the negative electrons are attracted by the positive, and this causes the device to 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 experiments of Galvani and Volta is retained.
Types of batteries include:
- the alkaline battery, carbon battery: zinc + manganese dioxide
- the traditional car battery: lead + lead dioxide
- the Li-ion: a collective name where lithium is always an active component, but which, in combination with many other metals, can form the basis of a lithium battery.
- Ni-Cd: nickel and cadmium
- Zinc-air battery: This is a unique case. In this battery, there is only one active element. The air that reacts with the zinc is around the battery. Therefore, this battery is equipped with a sticker that covers the holes and will let the necessary air through once it is removed. It is advisable to wait a few minutes after removing the sticker before using it.
