Comparison of fuel cells to galvanic cells

Question 1

Comparison of definitions?

Answer 1

Both electrochemical cells
FUel cells are a type of galvanic cell
Compare: reactants sourced internally/externally
Compare: (un)limited reactants
COmpare: needs recharging?

Question 2

Comparison of function?

Answer 2

Both convert chemical energy to electrical energy.
Galvanic cells best for portable items used intermittently.
Fuel cells best for both portable and fixed items used constantly.

Question 3

Energy transformations?

Answer 3

BOth from chemical to electrical

Question 4

Fuel efficiencies?

Answer 4

Fuel cells: 40-60%; up to 85% if heat produced by cell is also used to generate electricity.
Galvanic cell: 60-90%

Question 5

Typical applications of each?

Answer 5

Fuel cells: cars, buses, commercial electricity generation, emergency back up power supplies
Galvanic cell: primary cells for portable things eg. watches, hearing aids; secondary cells for cars, mobile phones, computers

Question 6

Advantages of fuel cells?

Answer 6

More energy efficient (explanation above)
Hydrogen fuel cells don’t produce greenhouse gases
Fuel cells generate electricity as long as fuel is supplied, whereas conventional batteries need to be recharged/replaced
Can use a variety of fuels
Electricity can be generated on site and users are not reliant on connection to an electricity grid. Waste heat can be used to heat water/provide heating.

Question 7

Disadvantages of fuel cells?

Answer 7

Require constant fuel supply
Can be expensive in their fuels, electrolytes and catalysts
For using fuel cells in transport, they’ll need an extensive network of hydrogen filling stations
Hydrogen in fuel cells often sourced from fossil fuels, resulting in energy loss and generation of ghg.
Issues associated with stoage and safety of hydrogen fuel.