How Do Alkaline Batteries Work

What are Alkaline Batteries?

β€œAn alkaline battery is a type of primary battery whose energy is derived from the reaction of zinc metal and manganese dioxide. It is also a disposable battery.”

The alkaline battery gets its name from the fact that it uses an alkaline electrolyte of potassium hydroxide (KOH) rather than the acidic ammonium chloride (NH4Cl) or zinc chloride (ZnCl2) electrolyte used in zinc-carbon batteries. Other battery systems use alkaline electrolytes as well, but the active materials for the electrodes are different.

Alkaline batteries have a higher energy density and a longer shelf life than zinc-carbon batteries of the LeclanchΓ© cell or zinc chloride types while providing the same voltage.

Table of Contents

Structure of an Alkaline Battery

To generate electricity, a typical battery requires three components:

  • Anode
  • Cathode
  • An electrolyte

Components of Alkaline Battery

  • Steel shell
  • Other important accessories: Negative component- primarily made up of a sealing ring, a copper needle, and a base.
  • Steel can
  • Separator paper
  • Conductive graphite
  • Cathode mix
  • Conductive graphite
  • Cathode mix
  • Collector nail
  • Sealing plug
  • Sealant
  • Negative cap

 

Construction of an Alkaline Battery

  • The battery’s body is made of a hollow steel drum. This drum contains all of the battery’s materials and also serves as the cathode.
  • The battery’s positive terminal protrudes from the top of this drum.
  • The inner peripheral surface of the empty cylindrical drum is moulded with fine-grained manganese dioxide (MnO2) powder mixed with coal dust. This moulded mixture serves as the alkaline battery’s cathode mixture.
  • A paper separator is placed on the inner surface of the thick layer of cathode mixture. Inside this paper separator, the central space is filled with zinc powder and a potassium hydroxide electrolyte.
  • The zinc acts as an anode, and its powder form expands the contact surface.
  • The electrolyte is held in place between the cathode (MnO2) and the anode by a paper separator soaked in potassium hydroxide (Zn).
  • To collect the negative charge, a metallic pin (preferably made of brass) is inserted along the central axis of the alkaline battery. This is known as a negative collector pin. This pin comes into contact with a metallic end-sealed cap.
  • A plastic cover just inside the Metallic end sealed cap electrically separates the positive steel drum and negative end cap of an alkaline battery.

Working of an Alkaline Battery

A cell of an alkaline battery is a section of the battery. In a chemical power supply, a dry battery is the primary battery. It’s a disposable battery of some sort. It converts chemical energy into electrical energy by using manganese dioxide as the positive electrode and zinc cylinder as the negative electrode to power an external circuit. Because zinc is more active than manganese in the chemical reaction, zinc loses electrons and is oxidised, whereas manganese gains electrons and is reduced.

First half reaction,

Zn (s) + 2HO– (aq) β†’ Zn(s) + H2O (l) + 2e– (eΒ° = – 1.28 V)

Second half reaction,

2MnO2 (s) + H2O (l) + 2e– β†’ Mn2O3 (s) + 2HO– (aq) (eΒ° = + 0.15V)

Overall reaction,

Zn (s) + 2MnO2 (s) β‡Œ Mn2O3 + Zno (s) (eΒ° = 1.43 V)

Sometimes alkaline batteries occasionally leak or explode. This happens due to an internal short circuit. On removing the sealing ring, the electric fluid inside will flow out.

Note- If the fluid comes into contact with the skin, immediately wash it with water.

Since the air volume in alkaline batteries is very small, one should not be concerned about explosions; at most, the bottom of the negative electrode rushes out, usually within 20 cm, causing no serious injury to personnel.

There is no spontaneous combustion substance in alkaline batteries because alkaline batteries, unlike lithium batteries, do not spontaneously ignite.

Types of Alkaline Batteries

1. There are four types of batteries based on the composition of the active materials in the plates. These are their names:

  • Nickel iron (or Edison).
  • Nickel- cadmium (or Nife).
  • Silver zinc.
  • Alkum battery.

2. These batteries can also be classified as sealed or non-sealed depending on how they are assembled.

3. The alkaline battery is also classified as an enclosed pocket or open pocket battery based on the design of the plates.

Applications

Toys, flashlights, portable electronic circuits, breadboard circuits and digital cameras.

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Frequently Asked Questions on How Do Alkaline Batteries Work

Q1

What are alkaline batteries?

Alkaline batteries are disposable batteries with electrodes made of zinc and manganese dioxide. Potassium or sodium hydroxide is the alkaline electrolyte used. These batteries have a constant voltage and are more energy dense and leak resistant than carbon zinc batteries.

Q2

Why is alkaline battery named so?

Primary batteries are alkaline batteries. The alkaline battery gets its name from its alkaline electrolyte of potassium hydroxide, as opposed to the zinc-carbon batteries’ acidic ammonium chloride or zinc chloride electrolyte.

Q3

What happens when an alkaline battery is charged?

It is dangerous to recharge alkaline batteries. If cycling is not maintained, too much heat can accumulate. This could result in an alkaline battery exploding, which is a bad scenario in any case.

Q4

What are advantages of alkaline batteries?

The advantages of alkaline batteries are-

  • This product has a high energy density.
  • This battery is equally effective in continuous and intermittent applications.
  • This performs equally well at low and high discharge rates.
  • This performs equally well at room temperature and at low temperatures.
  • The internal resistance of an alkaline battery is also low.
  • It has a sufficiently long shelf-life.
  • This battery has a low leakage rate.
  • It is more dimensionally stable.
Q5

What is the distinction between alkaline and regular batteries?

Due to the materials used, alkaline batteries last longer. The most noticeable distinction between alkaline and non-alkaline batteries is the amount of power they provide. Carbon batteries do not have the same lifespan as alkaline batteries.

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