Types Of Battery - Primary cell & Secondary cell

Introduction

Italian scientist Alessandro Volta in 1800 formed the battery and that's called the Voltas invention and also known by the name of voltaic Pile. The invention of the battery was a great discovery at that time. Before the battery, there were no electricity experiments because it was unsafe to experiment directly from the electricity. Many scientists contributed significantly to the electricity" namely Benjamin Franklin and Luigi Galvani. Luigi worked on animal electricity, which inspired him to answer various questions in his mind related to the electrical phenomenon. He is an Italian physicist who works on the frog's legs and discovers the animal's electricity. Alessandro Volta, Galvani is not satisfied with the concept of the idea of "animal electricity." Other than that he said that the electricity came due to the use of metal in that experiment process.

To conform his study or the concept, Alessandro formed the Voltaic Pile, which consisted of alternating discs of zinc and copper, separated by layers of cardboard soaked in saltwater. The pile produced a steady, continuous electrical current, unlike the sporadic sparks of static electricity. Volta’s goal was to create a reliable source of electricity that did not rely on mechanical friction or biological sources. His invention provided a constant and controlled flow of electric current, which was a significant advance over previous methods. The Voltaic Pile demonstrated that electricity could be generated chemically, and it laid the foundation for future developments in electrochemistry and electrical engineering. Volta’s invention was crucial in the development of electrical science. It led to further research and discoveries in electromagnetism and electrochemistry. The principles established by the Voltaic Pile influenced the creation of more advanced batteries and electrical devices.

The Voltas first invented the primary cell and further advancement was done by other scientists not just by one single scientist but by different scientists as British scientist John Daniell 1836 improved upon Volta's design with the Daniell Cell, which used copper and zinc electrodes and a more stable electrolyte solution (copper sulfate and sulfuric acid). This cell offered more consistent voltage and better performance compared to the Voltaic Pile. British chemist William Grove in 1839 created the Grove Cell, which utilized a combination of platinum and zinc electrodes with an acid and saline solution. These battery cells provide a more easily accessible current and improve the quality by using different electrolytes and the material used for them

The secondary cell was discovered by French engineer Gaston Plante They invented the lead-acid battery, the first commercially viable rechargeable battery. It used lead and lead dioxide electrodes with a sulfuric acid electrolyte. This type of battery is still used today in vehicles and for backup power systems. The Swedish engineer Waldemar Jungner developed the NiCd battery, which used nickel and cadmium electrodes. NiCd batteries were among the first widely used rechargeable batteries, suitable for portable electronics and tools.

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Types Of Batteries

Batteries can be categorized based on their chemistry, usage, and whether they are rechargeable or non-rechargeable.

Non-rechargeable batteries are called primary cell

Rechargeable batteries are called secondary cell

Primary Cells
In such cells, redox reaction occurs only once so cells can not be recharged again. The cell becomes dead after some time as electrode reactions cannot be reversed. For example, dry cells and mercury cells.

• Dry Cell
  • It is a compact form of the Lechlanche cell.
  • It has an anode of Zn-container and a cathode of graphite rod surrounded by MnO₂ + carbon.
  • Here a paste of NH₄Cl and ZnCl₂ is filled in between the electrodes.
    
    Cell Reactions
    At anode:
    Zn(s)→Zn+2(aq)+2e−
    At cathode:2MnO2( s)+2NH44(aq)+2e→Mn2O3( s)+2NH3( g)+H2O
  • Zn⁺² combines with NH₃ to form diammine Zn(II) cation.
  • A dry cell has a short life as NH₄Cl (acidic) corrodes the Zn-container even if the cell is not in use.
  • The cell potential is 1.25 to 1.5 volt
• Mercury Cell
  • In commonly used mercury cells the reducing agent is zinc and the oxidizing agent is mercury(II) oxide.
    
    Cell Reactions
    At anode:
    Zn(Hg)+2OH→ZnO(s)+H2U+2em
    
    At cathode:
    HgO+H2O+2e−→Hg(l)+2OH
  • 
    
    The overall reaction is:Zn(Hg)+HgO(s)→ZnO(s)+Hg(l)
  • The cell potential is approximately 1.35 V and remains constant throughout its life as the overall reaction does not involve any ion, whose concentration can change during its lifetime. It is used in hearing aids, watches, etc.

Secondary cell

A secondary cell, also known as a rechargeable battery, is a type of battery that can be recharged and used multiple times. Unlike primary cells, which are designed for single-use and must be disposed of once depleted, secondary cells can be restored to their full charge by applying an external electrical current.

Rechargeability
- Secondary cells can be recharged and used again after the initial discharge. This is achieved through a process where electrical energy is converted into chemical energy during charging.

Chemistry
- Various chemistries are used in secondary cells, including:
- Lead-Acid: Uses lead and lead dioxide electrodes with a sulfuric acid electrolyte.
- Nickel-Cadmium (NiCd): Uses nickel and cadmium electrodes with a potassium hydroxide electrolyte.

Applications
- Secondary cells are widely used in various applications, including:
- Consumer Electronics: Smartphones, laptops, tablets, and cameras.
- Electric Vehicles: Batteries for electric cars, bicycles, and scooters.
-*Power Tools: Rechargeable drills, saws, and other tools.
- Energy Storage Systems: Home energy storage and backup power solutions.

Advantages
- Cost-Efficient: Over time, secondary cells can be more economical than primary cells because they can be reused multiple times.
- Environmental Impact: Rechargeable batteries reduce waste since they do not need to be disposed of after a single use.
- Performance: Modern secondary cells often provide higher energy density and better performance compared to primary cells.

Disadvantages
-Initial Cost: Rechargeable batteries can be more expensive upfront compared to disposable ones.
- Maintenance: They may require specific charging protocols and can degrade over time, reducing their effective lifespan.

Secondary cells are essential in many modern technologies and applications due to their ability to be recharged and reused, contributing to more sustainable and efficient energy use.

For a better understanding of the topic and to learn more about Types Of Batteries - Primary cell & Secondary cell with video lesson we provide the link to the

YouTube video:

Some Solved Examples

Example.1

1. Choose the correct option :

a) Mercury batteries using a mercury oxide cathode have a flat discharge curve

b) Mercury batteries are used in voltage reference in electric instruments and in photographic light meters

c) Silver oxide batteries are used as an alternative to mercury batteries

1)a,b

2)b

3) (correct)a,b,c

4)a,c

Solution

Mercury batteries using mercury oxide cathode have a flat discharge curve and provide a constant voltage of 1.35 v for 95% of their lifetime. The rest is also correct.

Hence, the answer is the option (3).

Example.2

2 . Select the correct option in the context of dry cell

a) it is also called Lechlance cell

b) It can also be called Daniel cell

c) Electrolyte used is a moist paste of PbSO4 and PbSO4

1)a,c

2) (correct)c

3)a,b

4)b,c

Solution

As we have learned,

Batteries - Primary Cells
In such cells, redox reaction occurs only once so cells can not be recharged again. The cell dies after some time as electrode reactions cannot be reversed—for example, dry cells and mercury cells.

• Dry Cell
  • It is a compact form of the Leclanche cell.
  • It has an anode of Zn-container and a cathode of graphite rod surrounded by MnO₂ + carbon.
  • Here a paste of NH₄Cl and ZnCl₂ is filled in between the electrodes.
    Cell Reactions
    At anode:
    Zn(s)→Zn+2(aq)+2e−
  • 
    At cathode:2MnO2( s)+2NH4+(aq)+2e−→Mn2O3( s)+2NH3( g)+H2O
  • Zn⁺² combines with NH₃ to form diammine Zn(II) cation.
  • A dry cell has a short life as NH₄Cl (acidic) corrodes the Zn-container even if the cell is not in use.
  • The cell potential is 1.25 to 1.5 volt
• Lechlance and Daniel cells are different from dry cell

Hence, the answer is the option (2).

Example.3

3. A depolarizer used in dry cells is:

1)Ammonium chloride

2) (correct)Manganese dioxide

3)Potassium oxide

4)Sodium phosphate

Solution

As we have learned,

• Dry Cell
  • It is a compact form of the Leclanche cell.
  • It has an anode of Zn-container and a cathode of graphite rod surrounded by MnO₂ + carbon.
  • Here a paste of NH₄Cl and ZnCl₂ is filled in between the electrodes.
    Cell Reactions
    At anode:
    Zn(s)→Zn+2(aq)+2e−
  • 
    At cathode:2MnO2( s)+2NH4+(aq)+2e−→Mn2O3( s)+2NH3( g)+H2O
  • 
    
  • Zn⁺² combines with NH₃ to form diammine Zn(II) cation.
  • A dry cell has a short life as NH₄Cl (acidic) corrodes the Zn-container even if the cell is not in use.
  • The cell potential is 1.25 to 1.5 volts

MnO₂ acts as the depolarizer and presents the buildup of hydrogen gas molecules.

Hence, the answer is the option (2).

Example.4

4. Choose the incorrect option in the context of mercury cell :

a) AqO+KOH is used as an electrolyte

b) Zn is used as an electrolyte.

c) ZnO+KOH is used as an electrolyte

1)a,b.c

2) (correct)a,b

3)b,c

4)b

Solution

Electrolyte moist paste of KOH.

Cathode reaction IgO(s)+H2O(l)+2e−→Hg(1)+2OH−

Anode reaction Zn(Hg)+2OH−→ZnO(s)+H2O+2e−

ZnO+KOH◻ in the moist form is used as an electrolyte and zinc is used as an anode.

Hence, the answer is the option (2).

Example.5

5. Compound A used as a strong oxidizing agent is amphoteric. It is part of lead storage batteries. Compound A is:

1)PbO

2)Pb₃O₂

3) (correct)PbO₂

4)PbSO4

Solution

PbO₂ is an amphoteric and strong oxidizing agent and also a component of lead storage batteries in the cathode

Hence, the answer is the option (3).

Summary

Batteries are important as they provide a source of energy this feature makes them very important as they are used in mobiles and many more things. Dry cells are very small and easy to carry with them and due to their small size, they are very portable so they can be used in small devices which are movable devices like flashlights and remote controls. They are easy to handle and replace, with a long shelf life when unused. Unlike wet cells, dry cells don’t require maintenance or additional liquid. Mercury cells provide a consistent voltage output over a wide range of temperatures. The mercury cells have a long shelf life and maintain their charge for extended periods. Mercury Cell Compact Size: These cells are small and can be used in devices requiring precise, reliable power like hearing aids and wristwatches. However, mercury cells are less commonly used today due to environmental and health concerns related to mercury.

Over time, they are more economical because they can be reused multiple times. Though the initial cost might be higher, their ability to be recharged reduces the need for frequent replacements. Environmental Impact: Rechargeable batteries help reduce waste since they can be used repeatedly, leading to less battery disposal and environmental pollution.Performance: They often provide a higher energy density and can deliver more power compared to primary (non-rechargeable) cells. This makes them suitable for high-drain devices. these batteries are very Convenient as they are ideal for devices that need high power in a small compact size, as they can be recharged and used again rather than constantly needing fresh batteries.