An Introduction to Batteries: The Science Made Simple
This article is designed to provide a complete, reliable, and simple explanation of batteries. It is written based entirely on scientific research, and every piece of content is supported by real data. First, this article clearly explains the historical background of batteries. It explains how old batteries were created, what technologies they were based on, and how they worked.
What is a battery?
A battery is a device that stores electrical energy in advance through various chemical processes, providing it when needed.
It performs two main functions:
1. Storing energy
2. Releasing it when needed
Inside the battery, chemical changes take place. Through these changes, chemicals react with each other and generate electricity. This electricity is released through the movement of electrons. This is the basic process of a battery. Batteries are used in a variety of fields, from small electronic devices (watches, remote controls) to large electric vehicles and solar energy storage systems.
Thus, the battery is an important, scientifically based invention that plays a vital role in various aspects of our lives. Definitions given by scientists for a battery – a clear explanation. Various scientists have provided unique definitions based on their research about the functioning and importance of the battery. All of this is designed to explain the chemical basis of the battery.
Alessandro Volta, considered the father of it all, stated that when two different metals and a wet conductor are connected together, a continuous flow of electricity will be generated. Based on this, a battery is defined as a device that continuously generates electricity through chemical reactions.
Subsequently, Michael Faraday stated, “Electricity is the result of direct chemical changes.” Based on this, a battery is defined as a device that generates electricity using chemical reactions.
John Frederick Daniel emphasized that batteries should be capable of providing stable and safe electricity. Therefore, according to his definition, a battery is a source of electricity with a constant voltage.
Expanding on this, William Crowe stated that “chemical energy can be completely converted into electrical energy.” Based on this, a battery is defined as a device that completely converts chemical energy into electrical energy.
All of these definitions explain the basic operating principles of a battery:
• Chemical changes
• Movement of electrons
• Continuous power output
• Constant voltage
All of this forms the scientific foundation for how batteries work. Thus, each scientist has emphasized the key features of the battery according to their time.(1),(2),(3),(4),(5)
Main Parts of a Battery
1. Anode
2. Cathode
3. Electrolyte
4. Separator
5. Current Collectors
6. Battery Casing
7. Terminal Connectors
01. Anode – The oxidation center of the battery
The anode, one of the key components of a battery, is where oxidation takes place. When chemical changes occur at this location, electrons leave the anode and move through the external circuit. Through this, chemical energy is converted into electrical energy. When a battery is supplying electricity, the anode usually acts as the negative terminal. Since this is the initial stage of electricity generation, it plays a key role in the operation of the battery.
The structure of the anode and its performance vary depending on the type of battery:
• In lithium-ion (Li-ion) batteries, the anode is usually graphite. Since it is arranged in thin layers, it has a high ability to absorb lithium ions.
• In zinc-carbon batteries, zinc acts as the anode. It has properties suitable for oxidation.
Thus, understanding the anode forms the foundation for a deeper understanding of the cell's process and its design.(6),(7),(8)
02.Cathode – The end where electricity ends in a battery
The cathode, one of the key components of a battery, is where reduction takes place. It accepts electrons from the anode via an external circuit. These electrons combine with chemicals at the cathode, causing chemical changes. Through this, the chemical energy inside the battery is converted into electrical energy. When a battery is supplying electricity, the cathode usually acts as the positive terminal. Electrons leave the anode, travel through the external circuit, and end up at the cathode. This movement creates the flow of electricity.
Depending on the type of battery, the materials used for the cathode vary:
• In lithium-ion (Li-ion) batteries, lithium metal oxide is used as the cathode.
• In zinc-carbon batteries, manganese dioxide acts as the cathode.
These types of cathode systems determine the capacity, long-term performance, and safety of the battery. The cathode acts as the final stage where electrical energy is generated and the terminal at which the electrical circuit ends.(9),(10),(11)
03. Electrolyte – A chemical medium through which ions move.
The electrolyte plays a very important role in the functioning of a battery. It acts as a chemical medium between the anode and the cathode. While electrons move inside the battery, ions move through the electrolyte. It is through the movement of these ions that the necessary chemical changes can take place at the anode and cathode. The basic requirement for electricity to flow is that the path for electrons to move out and the path for ions to move in work together. The electrolyte is the crucial bridge between the two. Without the electrolyte, electricity cannot flow through the battery.
Electrolytes can be in many forms:
• Liquid
• Gel
• Solid
Depending on the type of battery, the composition of the electrolyte also varies:
• Lithium salt solution is used as the electrolyte in lithium-ion batteries.
• In lead-acid batteries, sulfuric acid acts as the electrolyte.
The electrolyte acts as the main catalyst that drives the process of converting chemical energy inside the battery into electrical energy. It is a scientific fact that without this, the battery cannot function.
04. Separator – The battery's safety guard
The separator is an important safety component in the operation of a battery. This will form a thin film, preventing the anode and cathode from touching directly. Without this protection, there is a possibility of the two ends being connected directly and causing a short circuit, This may cause hazards such as battery malfunction or explosion. The separator prevents electrons from flowing directly. But at the same time, it allows the process of ions moving through the electrolyte.
This allows chemical changes to take place inside the battery, but ensures that the circuit operates safely and in a controlled manner. Separators are typically made of polymer-based materials. Although they are thin, they are heat-resistant and chemically stable. The separator is an indispensable component because it is a key component that ensures not only the performance of the battery, but also its safety. Without this, there is a high risk of battery failure. Therefore, the design and quality of the separator determines the reliability of the battery.
05.Current Collectors – The main components that collect electricity in a battery
Current collectors in a battery are key components that conduct electrons generated at the anode and cathode to an external circuit. Although they do not directly participate in chemical changes, they play an important role in ensuring the smooth flow of electricity and reducing power loss. During the operation of the battery, electrons generated at the anode escape and travel through the current collector to the external circuit. Similarly, current collectors also act as a place to accept the arrival of electrons at the cathode. Thus, their main task is to create a path for the smooth flow of electricity.
Typically, the following materials are used as current collectors in batteries:
• For the anode: Copper
• For the cathode: Aluminum
These materials are chosen because they are very strong and highly conductive. They improve battery performance, reduce power loss, and help maintain a smooth flow of electricity. Finally, current collectors are indispensable because, while they do not participate in direct chemical changes inside the cell, they are key components that create a path for the electricity to flow out. Without these, the battery's function cannot be fully fulfilled.
06. Battery Casing
The battery casing acts as the main component that protects all the internal components of the battery. It is a casing that surrounds all the internal components such as the anode, cathode, electrolyte, separator, and current collectors. This casing protects the internal components of the battery from external damage, moisture, strong vibrations, and hazards such as short circuits. The battery casing ensures not only the battery's performance, but also its reliability and long-term use. Without this, the internal components of the battery are more likely to fail due to direct contact with the external environment.
Typically, battery casings are made of:
• Thin metals
• Plastics
• Chemical-resistant materials
These materials are capable of withstanding heat, humidity, and chemical influences. Therefore, the battery casing is the fundamental source for the safety, performance, and long-term use of the battery. It is a scientific fact that without this, a battery cannot function fully.
07.Terminal Connectors – The main connections that connect the battery to external devices.
Terminal Connectors are the key components that connect the battery's functionality to external devices. These are arranged so that the anode and cathode terminals of the battery are exposed. Without these connections, the battery cannot be connected to any device; therefore, no electricity can flow out. The electrons generated in the battery reach these terminal connectors through current collectors and from there pass to the external circuit. This creates the opportunity for the battery to provide power to a device. These help in smooth flow of electricity and reduce power loss.
Terminal connectors are usually made of metals that conduct electricity very well, such as copper, brass, or aluminum. These are strong and capable of providing flexible connectivity. In short, without terminal connectors, a battery cannot function with any device. Therefore, these are considered the main functional and application link of the battery. (12),(13),(14)
Early Batteries
Baghdad Battery – A fascinating insight into an ancient electrical invention
The Baghdad battery is an ancient electrical device believed to have been created in Mesopotamia around 2500 years ago. This is considered possible evidence of early human knowledge of electricity. This device is said to have been created with a metal tube in a clay pot and an acidic liquid. Some scientists who have studied its structure believe it may have been used to power small electrical wires or for electroplating metals such as gold. A device like this is possible evidence that ancient humans had some knowledge of electricity.
However, the actual use of this device has not yet been fully confirmed. Discussions about this continue among researchers. The Baghdad Battery is considered an important milestone in the history of electricity and a symbol of the time when man began to explore electricity. This is an important discovery that expands our understanding of the early period of scientific development.(15,16,)
Voltaic Pile – The first working chemical cell
The voltaic pile was the first working chemical cell, created by Alessandro Volta in 1800. This is considered a revolutionary advancement in electricity generating devices. This battery was a structure in which plates of different metals (usually copper and zinc) were stacked on top of each other, with wet paper or cloth placed between them. Through this system, continuous electricity generation was possible. This went down in history as the first device to convert chemical energy into electrical energy.
The voltaic pile, due to its simple design and efficiency, is the foundation of modern battery technology. This proved for the first time that electricity could be generated as a result of chemical changes. Even today, the voltaic pile holds a prominent place in the history of education and science as a clear, simple, and working model. This demonstrates how deep human knowledge was in the early stages of electrical research.(17,18)
Daniell Cell – Early battery that provided constant voltage
Daniell cells, invented in 1836 by John Frederick Daniell, are considered one of the first working chemical cells to provide a constant voltage. It was designed to solve the problem of variable voltage in early batteries such as the voltaic pile. In Daniell cells, two different metal electrodes were used—one zinc, the other copper. These were immersed in their own salty liquids: Copper sulfate in copper, zinc sulfate in zinc . These two liquids were connected by a separator or salt bridge. This structure allowed ions to move freely, allowing electricity to flow smoothly. This battery generated electricity with a constant voltage using chemical changes,
Therefore, it was widely used as the first practical battery in factories and laboratories. Daniel cells laid the foundation for modern battery designs. They proved that electricity was not just a research curiosity, but could also be a usable source of power. Its design is a significant advance in the history of science.(19,20)
Lead–Acid Battery – The first rechargeable battery
The lead-acid battery, invented by French scientist Gaston Planté in 1859, holds a significant place in history as the world's first rechargeable battery. It is one of the most reliable power sources that is widely used till today. In this cell, a pure lead plate and a lead dioxide plate act as the anode and cathode. Both of these are immersed in a liquid electrolyte called sulfuric acid. When a battery operates, chemical energy is converted into electrical energy through the changes that occur between these chemical elements. The main advantage of a lead-acid battery is that it can be recharged and used repeatedly.
Because of this, Lead–Acid Battery is widely used in many fields:
• In vehicles (mainly in the starter battery of cars)
• In backup power systems used in case of power outages
• In stationary energy storage systems
Despite its simple design, it still plays an important role in many applications today due to its reliability, low cost, and resilience. The lead-acid battery is a strong foundation for the development of modern energy storage technology.(21,22)
Conclusion: The journey of the battery and its importance
A battery is a device that stores electrical energy in advance through various chemical processes, providing it when needed. It is made up of key components such as anode, cathode, electrolyte, separator, current collectors, and terminal connectors. Each component plays a distinct role, helping electricity flow smoothly and safely. Scientists define a battery as
“a device that generates or stores electricity through chemical reactions.”
This definition clearly explains the basic operation of a battery. Looking at the history of batteries, from ancient potential electrical devices like the Baghdad battery to pioneering inventions like the voltaic pile, Daniel cells, and lead–acid batteries, man has made continuous advances in his attempt to generate electrical power. All of these form the basis for high-performance batteries such as modern lithium-ion, sodium-ion, NiMH, and solar batteries. In today's world, batteries are not just a power source for devices, but have become key pillars for green energy, electric vehicles, and a sustainable future. The development of the battery reflects the depth of human knowledge and the advancement of technology. It is a powerful tool for improving science, the environment, and the quality of human life.
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