Alkaline Batteries – Chemistry, Working, Types & Uses

Alkaline batteries are the most popular and the most widely used batteries in the market. Since they are mainly used for domestic and household purposes, these batteries are more familiar to the common people. Apart from other battery technologies, alkaline batteries are available in numerous sizes and capacities which make them suitable for diverse applications. The article will give you some fundamental knowledge of alkaline batteries.

What are Alkaline Batteries?

Alkaline batteries
Alkaline batteries

Alkaline batteries get their name because of the alkaline electrolyte used in them. They are usually known as primary batteries. But the rechargeable version of alkaline batteries is now available on the market. Alkaline batteries are the most plentiful and widely produced battery on Earth.

Want to start with the basics? Read this article: How does a battery work? Symbol, Chemistry, & Basics

They are known for their long shelf life of about 5-10 years and easy handling. The nominal voltage of alkaline batteries is 1.5V. The amount of current delivered is relative to the size of the battery. It provides an average of 2500 mAh capacity, which is highly dependent on the connected load.

Alkaline batteries are considered low-risk batteries since they are not prone to accidents and are suitable for regular disposal.

Construction of Alkaline Battery

An alkaline battery has Zinc as the anode and Manganese dioxide as the cathode. Potassium hydroxide (KOH) is used as the electrolyte. The zinc reacts with KOH to release electrons and form zinc hydroxide and water. The electrons released by the anode migrate to the cathode via the circuit. This powers the devices connected in the circuit.

Construction of an Alkaline battery
Construction of an Alkaline battery

Once the electron reaches the cathode, it reacts with Manganese dioxide and water to form Manganese tri-oxide and hydroxide ions. This reaction keeps repeating until the circuit is closed. Thus only the anode and cathode are consumed during the reaction. The electrolyte is replenished at every cycle.

You should know: How Batteries are Made? Materials used and Construction

Types of Alkaline Battery Sizes

One of the most highlighted advantages of alkaline batteries is that they are available in different sizes. The popular standard sizes of alkaline batteries are AA, AAA, A23, 9V, and button size.

Size AA

These batteries are known as “Double A Batteries”. The nominal voltage produced by AA batteries is 1.5V. They are mostly used in toys or alarm clocks.

Size AAA

These batteries are known as ‘Tripple A Batteries’. It is smaller than AA batteries. The nominal voltage is 1.5V. The manor application is in the remote control.

Size A23

This battery type is known for its large nominal voltage, which is 12V. These are cylindrical batteries and are usually used in garage controls.

Size 9V

Similar to its name, these batteries produce a nominal voltage of 9V. These are rectangular batteries. It is larger in size. These batteries are suitable to work in extreme temperature conditions. The major applications include smoke detectors, battery-powered temperature alarms, infrared thermometers, walk-in coolers, etc.

Button Size

These are tiny-sized batteries used in small devices like watches and headphones. It usually comes in a coin shape. The nominal voltage for these batteries is 1.5V.

Note: These are a few among the various different sizes of alkaline batteries. The details of more sizes can be found in this article: 9 Types of Battery Sizes & Where are they Used?

Rechargeable Alkaline Batteries

Although alkaline batteries are more popular as primary batteries, the rechargeable version of alkaline batteries is also widely accepted. They were introduced in the early 1970s. Rechargeable alkaline batteries are also known as Rechargeable Alkaline Manganese (RAM). The nominal voltage is 1.5V and is comparatively cheaper than other rechargeable batteries.

The rechargeable alkaline batteries are also known for their long shelf life. It also supports a good cycle life of about 500 charges if recharged properly (at regular intervals).

As with any other rechargeable batteries, deep discharge badly affects the life of these batteries too. They are easy to dispose of and have less environmental impact compared to other cells. The major applications of rechargeable alkaline batteries include remote control handsets, portable radios, etc. Read more.

Applications of Alkaline Batteries

Alkaline batteries are preferred for low-current drain applications. It includes:

  • flashlights
  • MP3 players
  • portable radios
  • alarm clocks
  • digital cameras
  • remote controls
  • toys, etc.

Read also: Guide to Li-ion batteries – Chemistry, Uses, Alternatives & FAQs

Advantages of Alkaline Batteries

The advantages of alkaline batteries make a long list. This is why alkaline batteries have become the most preferred choice for domestic as well as some industrial purposes. Here are some common applications of Alkaline batteries.

  • Alkaline batteries are known for a long shelf life of about 5-10 years.
  • It provides a high energy density when compared to the similar-sized zinc-carbon battery,
  • It is suitable to use in different temperature ranges.
  • It has non-toxic chemical composition. Thus it is safe to handle and dispose of.
  • It is one of the largest produced batteries on the market. Hence they are easily available.
  • It costs very less compares to other battery technologies.
  • It has standard sizing and is available in numerous sizes. It helps the developers to fit the battery easily in their designs.
  • It has a low risk of leakage compared to other batteries.
  • Although alkaline batteries are more suitable for low-current drain applications, they can provide high voltages by connecting them in series.
  • An alkaline battery is an ideal choice for potting.

Potting is filling an enclosure with a compound to increase shock resistance and create a barrier against moisture and corrosive materials.

Read also: Lead-acid Battery- Chemistry, Uses, Pros & Cons

Disadvantages of Alkaline Batteries

Alkaline batteries possess fewer drawbacks compared to other battery technologies.

  1. The alkaline batteries have more internal resistance compared to other batteries. This reduces the power output and reduces efficiency as well.
  2. Compared to the latest battery technologies like lithium-ion batteries, alkaline batteries are heavier and bulkier.
  3. Over time, the alkaline batteries are vulnerable to leakage of corrosive liquid that damages the devices they are in. This mainly occurs when the battery is placed for long periods in unused devices.

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