How does a battery work? Symbol, Chemistry, & Basics

Batteries are one of the most important inventions in history. They store energy that can be used to power devices like cell phones, laptops, and cars. But do you know how does a battery work? In this blog post, we’ll explore how batteries work, their types, and their basics. We’ll also discuss some of the applications of batteries. But before that, let’s look at the history of batteries.

History of batteries

Today the batteries are available in various shapes and sizes. But, the initial developments were bulky and much different from the current ones. Have a look at some of the initially developed batteries.

The wet cells

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Benjamin Franklin in the 18th century first created a setup that worked like a battery. In his setup, the electrodes were dipped in a jar containing an electrolyte. This setup was named the “Wet cells”.

The first true battery

Voltaic pile: The first battery
Voltaic pile: The first battery

With time, attempts were made to improve the performance of the battery. And Alessandro Volta came up with a design that performed a chemical reaction to store and release the charges. This arrangement then came to be known as “Voltaic Pile”.

Limitations

This model exhibited several limitations among which the corrosion of zinc plates was predominant. The Voltas battery went through several stages of evolution which improved its structure as well as performance. The corrosion of electrodes still remains unsolved but now with certain techniques, this process can be delayed.

New models

Voltaic Pile’s immediate successor was the Trough Battery and the journey went on. Now the type of batteries varies in size and models range from city clock batteries to heavy solar panels. Batteries are available in a numerous range of capacities and technology that suits the purpose.

What is a Cell?

A cell is a technical term for a single energy source that emits energy from a chemical reaction. This points to the fact that what we casually call a battery, is technically a cell. A cell is manufactured with a predefined volume of energy.

A single Cell
A single Cell

The requirement for more energy is achieved by combining multiple cells in series. This combination of cells is technically called batteries.

What is a Battery?

A battery is a combination of cells that stores energy in the form of chemical energy. It is available in different capacities according to which it can be used to power devices. The chemical reaction that happens in batteries causes the electrons to flow.

A battery with 6 cells
A battery with 6 cells

Batteries can power devices up to a limit that depends on the amount of energy stored and the load connected. The simple batteries used in households, which are usually called alkaline batteries power small devices. Once it drains out, it is thrown out. But reusable batteries are available on the market and can be recharged after use.

Types of battery

Battery varies in shape, size, capacity, and usage. As already mentioned batteries are available as rechargeable and non-rechargeable.

  • In small devices like watches, tiny round batteries are present (aka Coin cells)
  • And in devices like toys and remotes, cylindrical batteries are used (aka AA batteries)

Larger capacity batteries are used in laptops and other electronic devices.

What is the difference between a cell and a battery?

The battery is a conventional method of addressing these storage devices. The actual terminology for its single piece is ‘cell’. A cell is a single unit that provides electrical energy from the stored chemical energy. A battery is a collection of cells connected in any fashion to transfer energy.

Thus the battery is comparatively bulky and is capable to store more energy. So it is used to transfer energy for heavy loads. Perfect examples of a battery are the power bank and the inverter battery used in our houses. Even a 9 Volt battery is made up of six 1.5 V cells.

Note: For ease of understanding, this article uses the term ‘battery’ to address the energy storage unit.

Cell and Battery symbol

The symbol in the figure below is used to denote the presence of a battery or a cell in the circuit.

Representation of a cell
Representation of a cell
Representation of a battery
Representation of a battery

The short line denotes the negative terminal and the long line denotes the positive terminal. If only two lines are present (one short and one long) then it denotes a cell. But if multiple lines are present then it is a combination of cells, aka battery.

What are the components of a battery?

The three major components of a battery are cathode, anode, and electrolyte. A cathode is a positive terminal, an anode is a negative terminal and an electrolyte is a chemical substance that reacts with the terminals. The battery is connected to the circuit at these terminals.

These components are arranged carefully to ensure the perfect progress of chemical reactions as well as to ensure perfect insulation.

Structure of a battery

Let us discuss the basic structure of an ordinary alkaline battery, as shown in the figure below:

Structure of an alkaline battery
Structure of an alkaline battery

The outer plastic covering wrapped tight around the battery contains all the primary information such as the cell’s capacity, voltage, terminals, etc. It also has a key role to provide insulation to the battery.

Anode & Cathode identification

The plain end of an alkaline battery is the anode, while the popped-out region (the other end) is the cathode. Under the outer insulation, another covering of steel and nickel plating is present. It prevents the internal components from interacting with external atmospheric factors.

Multiple layers of different materials are present in the battery. These are placed in such a way that certain levels of voltage and current are maintained during the chemical reaction.

How does a battery work?

A battery consists of different materials made of atoms. A controlled reaction occurs inside the battery where the atoms interact with each other which causes free mobile electrons.

Reaction at anode

The anode is made of zinc. The atoms in electrolytes combine with the zinc atoms and undergo oxidation. As a result, free electrons are released which get collected under the brass pin.

Reaction at cathode

The cathode is made of manganese oxide. The atoms in the electrolyte combine with the manganese oxide atoms and undergo reduction.

Accumulation of electrons

As electrons are negatively charged, the accumulation of electrons under the brass pin makes it a negative terminal, while the other end of the battery becomes a positive terminal. This creates a potential difference at the two ends of the battery.

Movement of electrons

The free electrons have a tendency to move towards the positive terminal. But, due to a separator between both terminals, this movement does not occur. Hence, when the battery is not connected to any circuit, no electron movement happens.

When a battery gets connected to a circuit, it creates a path for the electrons to reach the positive terminal. Hence a conventional current starts flowing, opposite to the direction of electron flow. In this way, a battery works in a circuit.

Applications of Battery

The invention of batteries revolutionized our lives. Almost all the devices that we use now contain a type of battery inside it. Though the applications make a long list, let us see some of the prominent ones.

  • In houses, we use batteries to power remote controls, torchlight, etc.
  • In our day-to-day life, rechargeable batteries are used in digital cameras, cellphones laptops, etc.
  • Batteries are also used in health instruments such as hearing aids, valve assisting devices, artificial limbs, etc.
  • The batteries are also used in the medical sector. A particular example is an ECG heart monitor which should be kept ON all the time. Lithium-ion and nickel batteries are mostly utilized for such purposes.
  • The battery acts as a safety backup that can be used where there is a fluctuating power supply or unavailability of power.
  • Batteries in wireless receivers and radios for Military operations are another vital application.
  • One of the most celebrated applications of batteries is in the case of electric vehicles. Lithium-ion batteries are used to power automobiles that promote pollution-free as well as cost-effective transport.

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