2. 1. Introduction
2. Design Principle & operation of Fuel Cell.
3. Types of Fuel Cells.
4. Comparison of Fuel cell with Battery and IC Engine
5. Fuel Cell Efficiency.
6. Advantages and Disadvantages
7. Application of Fuel Cell.
8. Recent Development.
3. What is a Fuel Cell ?
1. A fuel cell is an electrochemical energy conversion
2. A fuel cell converts the chemicals hydrogen and oxygen
3. A fuel cell is a device that generates electricity by a
4. Every fuel cell has two electrodes, one positive and one
negative, called cathode and anode respectively. The
reactions that produce electricity take place at the
4. Why we need Fuel Cells ?
1. Due to energy crisis all over the world.
2. Due to the issue of global warming.
3. Due to the unavailability of different renewable sources at each and
every place due to geographic condition.
4. Fuel cell provides an alternate efficient non polluting power source that
produces no noise and has no moving parts.
5. It is expected that by 2050 the global energy demand is going to rise by
2 to 3 times.
5. The basic principle of the fuel cell is illustrated in the
The core of each fuel cell consists of an electrolyte and
At the negative anode, a fuel such as hydrogen is being
oxidized, while at the positive cathode, oxygen is reduced.
Ions are transported through the electrolyte from one side
to the other.
Chemistry of fuel cell:
At Anode:- 2H2 → 4H+ + 4e-
At Cathode:- O2 + 4H+ + 4e- → 2H2O
Net Reaction: 2H2 + O2 → 2H2O
6. Classification of fuel cells is very difficult as several operational variable exists.
1. Based on the temperature range in which they operate: low temperature(25-
100), medium temperature (100-500) , high temperature(500-1000) & very
high temperature(above 1000)
2. According to the type of electrolyte : aqueous, non aqueous, molten or solid.
3. According to the physical state of the fuel: Gas(hydrogen, lower hydrocarbons)
, Liquid(alcohols, hydrazine, higher hydrocarbons), Solid(Metals).
Another Classification :
1. Primary fuel cell: Reactants are passed through the cell only once & the
products of the reaction being discarded. (H 2 – O 2 fuel cell )
2. Secondary fuel cell: Reactants are passed through the cell many times
because they are regenerated by different methods.( Nitric oxide – chlorine
8. 1. 40% KOH solution as electrolyte (Ion exchange membrane).
2. The membrane is non permeable to the reactant gases, hydrogen and oxygen,
which thus prevents them from coming into contact.
3. The membrane is however , permeable to hydrogen ions which are the current
carriers in the electrolyte.
4. The desired properties of an ideal ion exchange membrane electrolyte are:
a) High ionic conductivity.
b) Zero electronic conductivity
c) Low permeability of fuel and oxidant
d) Low degree of electro-osmosis.
e) High resistance to dehydration.
f) High resistance to its oxidation or hydrolysis and,
g) Mechanical stability
9. 1. The most interesting fuel cells for the near future are modified hydrogen- oxygen
cells, in which a gaseous or liquid hydrocarbon is the source of hydrogen.
2. Coal may be serve as the primary energy source for fuel cells. Cells based on fossil
fuels have three main components.
a) The fuel processor which converts the fossil fuel into a hydrogen rich gas.
b) The power section consisting of the actual fuel cell (or combination of cells), and
c) The inverter for changing the direct current generated by the fuel cell into alternating
current to be transmitted to user.
10. 1. In this the ammonia gas obtained from the stored liquid is decomposed
catalytically into hydrogen and nitrogen.
2. Part of the hydrogen is burned in air to provide the heat required for the
3. Other hydrogen is supplied to the negative electrode of the hydrogen cell in
which potassium hydroxide is used as electrolyte.
4. The nitrogen produced due to decomposition is an inert gas and plays no roll
in the cell.
5. The advantage of ammonia as fuel is that it can be stored in the liquid
6. The disadvantage include higher vapour pressure and cell operate
satisfactory at low temperature.
11. 1. A compact fuel cell for mobile application possibly for vehicle propulsion
utilizes the liquid hydrazine as a fuel and hydrogen peroxide or air as the
2. Hydrazine is injected as required into the aqueous potassium hydroxide
electrolyte to provide the active material at the negative electrode.
3. The oxygen is either supplied by decomposition or from air.
4. The electrode is made up of nickel (negative) or silver (positive) as the
5. The overall cell reaction is the oxidation of hydrazine to water and nitrogen, but
the discharged e.m.f is similar to that of the hydrogen oxygen cell.
12. A regenerative fuel cell is one in which the
fuel cell product (water) is recovered into
the reactants (hydrogen and oxygen) by one
of the several possible methods – thermal,
chemical, photochemical, electrical and
There are two stages in a regenerative fuel
a) Conversion of fuel cell reactants into
products while producing electrical
b) Reconversion of fuel cell products into
Hydrogen Fuel Cell Galvanic Cell (Battery)
01 Open system Closed system
02 Anode and cathode are gases make
contact with a platinum catalyst.
Anode and cathode are
03 Reactants are externally supplied, no
Reactants are internally conducted, require
Hydrogen Fuel Cell IC Engine
01 Output is electrical work. Output is mechanical work.
02 Fuel and oxidant respond
Fuel and oxidant reacts by the
process of combustion.
03 Modest to nil pollution produced Use of fossil fuels can generate
1. Both use hydrogen-rich fuel.
2. Both employ compressed air as the oxidant.
3. Both require cooling.
15. 1. 40% efficiency generated, converting methanol to
hydrogen in reformer
2. 80% of hydrogen energy content converted to electrical
3. 80% efficiency for inverter/motor – Converts electrical to
4. Overall efficiency of 24-32%
16. 1. Fuel cell system are ecofriendly.
2. High conversion efficiency .
3. Extremely low emission.
4. Noise less operations so readily accepted in residential areas.
5. Availability to use at any location. So less transmission & distribution losses.
6. No requirements of cooling tower as conventional plants.
7. Less space require as compared to conventional plants.
17. 1. Higher Initial Cost.
2. Lower Service Life.
3. Fuelling fuel cells is still a major problem since the production, transportation,
distribution and storage of hydrogen is difficult.
4. The technology is not yet fully developed and few products are available.
5. Fuel cells are currently very expensive to produce, since most units are hand-made.
18. The application of the fuel cell may be discussed in the following areas.
1. Domestic Power
2. Central Power Station.
3. Automotive Vehicles.
4. Special Application
19. 1. LLC, Latham, NY has successfully developed 50 KW power plant.
2. Fuel cell of capacity 1.5KW is powering houses in Australia.
3. GAIL is actively involved in establishing fuel infrastructure for fuel cell vehicles
4. CECRI, Karaikudi has developed and tested MCFC stack.
1. Ministry of NCES
3. CSIR labs