Before we get to the answer, let’s quickly talk about what a battery actually is. Chemical energy is stored in the battery, which in turn is converted into an electrical form.
Batteries consist of electrochemical devices such as one or more electrochemical cells, flow cells, or fuel cells. External connections provide power to electronic devices.
Batteries have a long history.
Although the Baghdad battery you see in the photo is thought to be the oldest known man-made battery, this claim is speculative. This clay pot, which is estimated to have been used between 250 BC and 640 AD, was thought to be an ancient “voltaic battery” because there was a copper cylinder and an iron rod fixed inside this cylinder, but these claims are considered as products of pseudoscience. After the US invasion of Iraq in 2003, the Iraqi National Museum was looted, and the Baghdad battery disappeared.
Speaking of “voltaic battery”; The modern development of batteries took place in 1800 thanks to the Italian physicist Alessandro Volta.
Thanks to this revolution that took place with the voltaic battery, batteries spread over a wide area. The reason why the unit of electromotive power or voltage is called volt is Volta’s work. Volta’s work is based on the work of Luigi Galvani.
Coming to the answer to our main question;
Let’s take a battery powered device, since it requires 3V to operate, two AA batteries of 1.5V each are needed. To get 3V from these two batteries, they must be connected in series because current can flow through it.
So what is connecting in series?
We can call it tying one after the other. Just as we place batteries one after the other in a flashlight, that is, the + and – ends touch each other, these ends of the batteries placed side by side should be as close to each other as possible.
As you can see in this image, if the same ends were facing the same place, an extra cable would be needed.
Since this is extra material and labor, the most economical and practical method is logically preferred. Every millimeter needs to be considered when designing a product, even the inclusion of an extra wire is seen as a waste and adds to the cost of production. It is the most efficient design in terms of total volume.
Therefore, these contacts are used for two different ends to come into contact:
In fact, the most logical design is this type of battery in the image, but since others are more common around the world, it has not had a say in the market.
Sources: Science ABC, Wikipedia, Wikipedia 2, Wikipedia 3