Written by Sarya Gulec
Today, batteries hold great prominence for human civilization as they enable efficient energy transportation and instant charging opportunities. In a world without batteries; phones, computers, and similar electronic devices would be much harder to recharge as plug usage would be obligatory. In this article, the historical importance and mechanics of the battery will be explained.
The history of batteries started when Italian scientist Allesandro Volta developed the first battery, opening the gate for further discoveries. Later in 1780, Galvani showed that frogs' legs hanging on iron or brass hooks would twitch when touched with a probe of some other type of metal. He believed this electricity came from the frogs’ tissues, calling it “Animal Electricity.”
Volta was initially impressed with Galvani’s findings. However, he realized that the electric current was coming from the iron hooks to the probe’s metal and was merely being transmitted through the frogs’ tissues. He experimented with stacks of layers of silver and zinc interspersed with layers of cloth or paper soaked in salt water and found that an electric current did flow through a wire applied to both ends of the pile.[3]
Batteries store chemical energy and convert it to electricity, just like many other energy sources we use. For example, logs and oxygen store energy in their chemical bonds until burning converts some of that chemical energy to heat.[4] Gasoline and oxygen mixture also stores chemical energy until converted to mechanical energy in a car engine. Similarly, converting electricity to chemical energy is essential to store energy.
Batteries consist of two electrical terminals called the “cathode” and the “anode,” the positive and negative sides of a battery connected in an electrical circuit, separated by a chemical material called an “electrolyte.” This system is known as electrochemistry, and the system that underpins a battery is called an electrochemical cell.[5] This causes an electrical difference in the anode and cathode. Electrons want to rearrange themselves to eliminate this difference; therefore, they repel each other and move somewhere else with fewer electrons.
Electrons move through the circuit, while ions (atoms or molecules with an electric charge) simultaneously move through the electrolyte.[3] In a rechargeable battery, electrons and ions can move in both directions through the circuit and electrolyte. Electrons increase the chemical potential energy when they move from the cathode to the anode, thus charging the battery. When electrons move in the other direction, they convert this chemical potential energy to electricity in the circuit and discharge the battery. During charging or discharging, the oppositely charged ions move inside the battery through the electrolyte to balance the charge of the electrons moving through the external circuit and produce a sustainable, rechargeable system.[3] Once charged, the battery can be disconnected from the circuit to store the chemical potential energy for later use as electricity.
Electrodes
To have an electron flow, you should have areas electrons can flow from and flow to. The electrons flow from a negative electrode called the anode to a positive electrode called the cathode. These electrodes are usually of different metal types or other chemical compounds.
In Volta’s pile, zinc was the anode, and silver oxide was the battery’s cathode. He stacked many of these cells together to make the total pile and activate the voltage.[1,4]
Electrons have a negative charge. As we send the flow of negative electrons through our circuit, we need a way to balance that charge movement. The electrolyte provides a medium through which charge-balancing positive ions can flow.[3]
References:
1. (50), moelflow, & (48), minnowpond1. (n.d.). Electrochemistry - what is voltaic cells?. Steemit. https://steemit.com/science/@moelflow/electrochemistry-what-is-voltaic-cells
2. Batteries, circuits, and transformers. (2022, December 16). U.S. Energy Information Administration (EIA). https://www.eia.gov/energyexplained/electricity/batteries-circuits-and-transformers.php
DOE. (n.d.). DOE Explains...Batteries. Energy.gov. https://www.energy.gov/science/doe-explainsbatteries
How a battery works. (2022, March 11). Curious. https://www.science.org.au/curious/technology-future/batteries
How do batteries work? (n.d.). Northwestern QRG. https://www.qrg.northwestern.edu/projects/vss/docs/power/2-how-do-batteries-work.html
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