5.4.4 Commercial Cells

Question 1

What are the different types of commercial cells?

Answer 1

• Rechargeable cells
• Non-rechargeable
• Fuel cells

Question 2

What factors do the types of cells depend on?

Answer 2

• Voltage required
• Current needed
• Size of cell
• Cost

Question 3

What is a battery

Answer 3

• A collection of cells joined together

Question 4

Disadvantages of non-rechargeable cells

Answer 4

• Impractical as a portable device due to hazardous liquids
• Corrosive contents can cause casing to wear away, causing electrolyte to leak out (zinc-carbon cells)
• Irreversible, cannot be recharged

Question 5

Advantages of non-rechargeable cells

Answer 5

• Cheap
• Long life
• Torches, radios, clocks

Question 6

How do rechargeable cells work?

Answer 6

• Chemical reaction reversed by applying voltage greater than the cell voltage
• Electrons pushed in opposite directon
• Lead-acid batteries
• NiCad cells
• Lithium cells

Question 7

What is a lead acid battery made of?

Answer 7

• 6 cells joined in series
• Lead is negative electrode
• Lead IV Oxide positive electrode
• Sulphuric acid electrolyte

Question 8

Advantages of lead acid batteries (rechargeable ones)

Answer 8

• High current for short period of time (good for starting cars)
• Can be reused

Question 9

Disadvantages of lead acid batteries (rechargeable ones)

Answer 9

• Very heavy
• Toxic materials (lead and lead IV oxide)
• Sulphuric acid is VERY corrosive
• So hard to dispose of

Question 10

What are NiCad cells? Advantages and disadvantages?

Answer 10

• Nickel (negative electrode)
• Cadmium (positive electrode)
  .
  Adv :
• Can be recharged a lot
• Commercially valuable
  .
  Disadv :
• Expensive
• Cadmium is a toxic metal, so disposal causes environmental issues