What is a Dry Cell?

Many of the electronic devices in our day-to-day life use dry cells like a TV remote control, children’s toys, wall clock, etc. It is a type of electric battery and consists of electrochemical cells. It converts chemical energy into electrical energy with the help of which our electronic devices work. The first commercial electrochemical cell was developed by a German Scientist named Carl Gassner in 1886 after the development of wet zinc-carbon batteries.

In this article, we are going to study the definition of dry cell battery, its structure, working, uses and advantages.

History of Dry Cell- Carl Gassner

Carl Gassner (17 November 1855 in Mainz – 31 January 1942) was a German physicist, scientist, and inventor best known for improving the Leclanché cell and fostering the development of the first dry cell, also known as the zinc–carbon battery, that was less likely to break or leak and could be mass-produced on a large scale.

Structure of Dry Cell

A commonly used dry-cell battery is made of up zinc-carbon battery which is cuboidal or cylindrical in shape. The outer container of the cell is made up of zinc which acts as an anode and the central carbon rod which is surrounded by a mixture of carbon and manganese dioxide (MnO2) acts as a cathode.

A paste of ammonium chloride (NH4cl) is filled in the rest of the body of the cell which acts as an electrolyte. Also, there is a separator that is present in between the ammonium chloride and zinc. It helps in preventing any kind of reaction between them. The diagram given below will give us a better view regarding the structure of dry cells.

Working of Dry Cell

Chemical Reactions are at the heart of a dry cell's operation. Electrons travel from one electrode to the other as a result of interactions between the electrolyte and the electrodes. Acids, for example, dissolve in water and generate ionized particles. There are two types of ionized particles. The positive ions are referred to as cations, while the negative ions are referred to as anions. The acids that dissolve in water are referred to as electrolytes..

The electrolyte in the above-mentioned diagram is zinc chloride. Ammonium chloride jelly can also be used as an electrolyte. Electrodes are formed by metal rods immersed in electrolytes. A positive electrode serves as the anode, and a negative electrode serves as the cathode, based on the chemical properties of the metal rods.

The oppositely charged ions are drawn to the electrodes. The anode attracts the cations, while the cathode draws the anions. Electrons flow from one direction to the other in this process, resulting in a charge flow. This is referred to as current.

Chemical Reactions Inside the Dry Cell

The components that are present inside the cell i.e, zinc, carbon, manganese dioxide, and ammonium chloride react with one another through a chemical reaction. These chemical reactions are called the half cell reaction process which has the following steps.

Step 1:

• In this step, a reduction reaction occurs between manganese dioxide (MnO2) and ammonium chloride (NH4cl). The carbon form of graphite acts as a supporter during this reaction. So, the reduction reaction is given as,

• $2NH_4^++2MnO_2\longrightarrow Mn_2O_3+H_2O$

Step 2:

• In this step, the zinc container which acts as anode undergoes an oxidation reaction and it is given as,

• $Zn\longrightarrow Zn^{2+}+2e^-$

The most commonly used cell is the zinc-carbon cell and it is also called the Leclanche cell. The same kind of half cell reactions occurs in alkaline batteries in which KOH or NAOH replaces the ammonium chloride. Now, the half cell reactions are,

$Zncl_2+2NH_3\longrightarrow Zn(NH_3)_2cl_2$

$MnO_2+H_2\longrightarrow Mn_2O_3+H_2O$

Therefore, the overall cell reaction is written as,

$Zn+2MnO_2+2NH_4cl\longrightarrow Mn_2O_3+Zn(NH_3)cl_2+H_2O$

Thus in this way, the cell works through these reactions to provide the necessary potential difference for conduction of electric current.

Difference Between a Dry Cell and Wet Cell

• In electricity, a battery consists of several electrochemical cells which convert the stored chemical energy to electrical energy and the dry cell is one of the general types of it.

• Basically, it consists of a low moisture electrolyte in the form of a paste which resists it from flowing and makes it suitable for use in portable equipment. Unlike the wet cell battery that contains a liquid electrolyte, one of the typical examples of it is lead-acid batteries.

• One of the problems of wet cell batteries is that they need to be handled carefully so that the liquid present in them should not be spilled out.

Uses of Dry Cell

They are the most commonly used battery type in electronic devices. So the uses of it are as follows.

• For small handheld devices such as calculators, clocks, and watches we use alkaline batteries as they provide high capacity outputs.

• Devices like cameras and smoke alarms work well with lithium batteries as they require minimum output and lithium batteries contain three volt capacity per cell.

• Most of the small motor designs use dry cell sources for their operation. Nickel-metal hydride, lead-acid gel, and nickel-cadmium are some of the examples of it.

Advantages of Dry Cell

• Dry cells have high energy density so they are easy to make in compact sizes and hence they are easy to carry and transport.

• They are very cheap and easily available.

• They have very low hazardous effects on our environment.

• There is no fear of any kind of linkage in them.

Interesting Facts About Dry Cell

Did you know that dry cells can be recharged?

Yes, let us have a look at this fact. All of the electrons are in the anode when a battery is fully charged. When it stops working, it implies that the majority of the electrons have migrated to the cathode. Some, but not all, batteries can be recharged. When we connect them to an external power source, we reverse the process and return the electrons to their proper location.

Some people, though, become lost along the road. As a result, each time we recharge a battery, it becomes weaker. That's why your phone and watch batteries survive for a shorter and shorter period of time before needing to be replaced.

Conclusion

We can conclude that a dry cell is one of the greatest inventions of all time, it has become an essential part of our livelihood. In this article, we have seen how dry cells work, structure of the dry cell, and how they're used. It's worth noting that the battery only works when the electrodes are physically in contact with one another. Between the two electrodes, there must be a conducting medium.