A fuel cell converts hydrogen and oxygen into electricity, heat, and water through an electrochemical reaction. It has four main parts: an anode, cathode, catalyst, and proton exchange membrane. There are different types of fuel cells that use various electrolytes. Fuel cells have advantages like high efficiency, zero emissions, and quiet operation. Applications include stationary power sources, transportation, portable devices, and distributed power generation. Research continues to improve fuel cell performance and reduce costs.
3. A fuel cell is an electrochemical energy conversion
device that converts hydrogen and oxygen into
electricity, heat, and water as a result of a chemical
reaction.
1. Introduction
•Fuel and air react when they come into contact
through a porous membrane (electrolyte) which
separates them.
•This reaction results in a transfer of electrons and ions
across the electrolyte from the anode to the cathode.
5. (+)
(-)
Anode Cathode
Electrolyte
2.Parts of a fuel cell.
A fuel cell configuration
There are 4 main parts
• Anode
• Cathode
• Catalyst
• Proton exchange
membrane
(or)
• Solid oxide
electrolyte
6. The anode is the negative post of the fuel cell.
It conducts the electrons that are freed from the
hydrogen molecules so that they can be used in an
external circuit.
It has channels etched into it that disperse the
hydrogen gas equally over the surface of the
catalyst
7.
8. The cathode is the positive post of the fuel cell.
It has channels etched into it that distribute the
oxygen to the surface of the catalyst.
It also conducts the electrons back from the
external circuit to the catalyst, where they can
recombine with the hydrogen ions and oxygen to
form water.
9. The catalyst is a special material that facilitates
the reaction of oxygen and hydrogen.
It is usually made of platinum powder very thinly
coated onto carbon paper or cloth. The catalyst is
rough and porous so that the maximum surface
area of the platinum can be exposed to the
hydrogen or oxygen.
The platinum-coated side of the catalyst faces the
PEM.
10. The electrolyte is the proton exchange membrane.
This is a specially treated material that only
conducts positively charged ions.
The membrane blocks electrons.
12. 3. Types of fuel cells
There are different types of fuel cells, differentiated by the
type of electrolyte separating the hydrogen from the
oxygen. The types of fuel cells are:
• Alkaline fuel cells (AFC)
• Direct methanol fuel cells (DMFC)
• Molten carbonate fuel cell (MFFC)
• Phosphoric acid fuel cells (PAFC)
• Polymer electrolyte membrane fuel cells (PEMFC)
• Solid oxide fuel cells (SOFC)
13.
14. Used in spacecraft to provide drinking water and
electricity
Electrolyte: Aqueous solution of alkaline potassium
Hydroxide
Output of 300W -5KW
Power generation efficiency of about 70%
Too expensive for commercial applications
15. Used in hospitals, nursing homes and for all
commercial purposes
Electrolyte: Liquid Phosphoric acid
Catalyst: platinum
Electrical efficiency of 40%
Advantages :using impure hydrogen as fuel and
85% of the steam can be used for cogeneration
16. Also called as Solid Polymers and used for quick
startup in automobiles, light duty vehicles and
potentially to replace rechargeable batteries
Electrolyte :Solid organic polymer poly-
perflourosulfonic acid.
Catalyst: Metals (usually platinum) coated on both
sides of membrane act as catalyst
Advantages: Use of solid electrolyte reduces
corrosion and management problems
17. Majorly used for electric utility applications
Electrolyte: Liquid solution of lithium, sodium
and/or potassium carbonates.
Catalyst: Inexpensive metals can be used as
catalyst other than Platinum
Advantages: High operating temperature allow for
inexpensive catalysts
18. Highly promising fuel cell
Used in big, high-power applications including
industrial and large-scale central electricity
generating stations
Some developers also see SOFC use in motor
vehicles
Power generating efficiencies could reach 60%
and 85%
19. Principle:
The fuel is oxidized on
the anode and oxidant
reduced on the cathode. One
species of ions are
transported from one
electrode to the other
through the electrolyte to
combine there with their
counterparts, while electrons
travel through the external
circuit producing the
electrical current.
Electrons
(e-
)
Fuel
Permeable
Anode
Electrolyte
Oxidant
Permeable
Cathode
Fuel Oxidant
Cations
(+ve)
Anions (-ve)
4. Principle, construction and working
of H2-O2 fuel cell
20. Working
The Fuel gas (hydrogen rich) is passed towards the
anode where the following oxidation reaction occurs:
H2 (g) = 2H+ + 2e-
The liberated electrons from hydrogen in anode side do
not migrate through electrolyte.
Therefore, they passes through the external circuit
where work is performed, then finally goes into the
cathode.
On the other hand, the positive hydrogen ions (H+)
migrate across the electrolyte towards the cathode.
21. At the cathode side the hydrogen atom reacts with
oxygen gas (from air) and electrons to form water as
byproduct according to:
H2 + 1/2 O2 +2e-
H2O + Heat
fuel + oxidant product + Heat
The overall cell reaction is
25. The liberated electrons from the hydrogen are responsible for the
production of electricity.
The water is produced by the combination of hydrogen, oxygen
and liberated electrons and is sent out from the cell.
The DC current produced by fuel cell is later converted into AC
current using an inverter for practical application.
The voltage developed in a single fuel cell various from 0.7 to 1.4
volt.
More power can be obtained by arranging the individual fuel cell
as a stack. In this case, each single cell is sandwiched with one
another by a interconnect.
Therefore, electricity power ranging from 1kW to 200 kW can be
obtained for domestic as well as industrial application.
26. (a) Anode:
(b) Cathode:
• Cermet of Ni and type of
electrolyte.
• Thickest and strongest
• Oxidize the H2 Fuel
• Lanthanum Strontium
Magnetite(LSM)
• Similar thermal coefficient as of
electrolyte.
• Reaction occurs at triple phase
boundary.
27. (a)Electrolyte:
(d) Inter Connect :
• The interconnect can be either a metallic or ceramic
layer
that connects each individual cell.
• Chromium and steel-based alloys are mostly used.
• 95Cr-5Fe alloy.
The electrolyte is a dense layer of ceramic that
conducts oxygen ions.
Most Popular Electrolytes are :
• Yttria Stabilized Zirconia (YSZ)
• Gadolinium Doped Ceria (GDC)
29. Advantages
• Zero Emissions: a fuel cell vehicle only emits water
vapour. Therefore, no air pollution occurs.
• High efficiency: Fuel cells convert chemical energy
directly into electricity without the combustion
process. As a result, Fuel cells can achieve high
efficiencies in energy conversion.
• High power density: A high power density allows
fuel cells to be relatively compact source of electric
power, beneficial in application with space
constraints.
5. Advantage, disadvantage and
applications
30. • Quiet operation: Fuel cells can be used in
residential or built-up areas where the noise
pollution can be avoided.
• No recharge: Fuel cell systems do not require
recharging.
Disadvantages
• It is difficult to manufacture and store pure hydrogen
at higher pressure.
• It is very expensive as compared to battery
31. The high temperature limits applications of SOFC
units and they tend to be rather large
While solid electrolytes cannot leak, they can
crack.
Complex materials
Assembling
Maintenance
Design Cost & choice of material
33. (a) Stationary energy resources:
•Power for municipalities, rural areas and industries.
•Heat and electricity for homes.
•Long-lasting mobile power for computers, cell
phones and other electronics
(b) Transportation:
•Non polluting automobiles
•Inexpensive fuels
(c) Military applications:
• Fuel cells could significantly reduce deployment
costs
Other Applications
34. 1. Portable applications
• They used in portable appliances and power tools
• They can be used in small personal vehicles
• They are used Consumer electronics like laptops, cell
phones can be operated
• They can be used in Backup power
A laptop using a fuel cell power source can
operate for up to 20 hours on a single charge
of fuel (Courtesy: Ballard Power Systems
35. 2. Transportation applications
• They can be used for transport application in the
following areas,
• Industrial transportation
• Public transportation
Commercial transportation
(truck, tractors)
• Marine and Military
transportation
36. 3. Power distribution application
• Fuel cells can be used for the distribution of power
in various fields such as,
• Homes and small businesses
• Commercial and industrial sites
• Remote, off-grid locations (telecom towers, weather
stations)
37. Research
• Research is going now in the direction of lower-
temperature SOFC (400°C) in order to decrease
the materials cost, which will enable the use of
metallic materials with better thermal conductivity.
• Research is also going on in reducing start-up
time to be able to implement SOFCs in mobile
applications.
• Research is currently underway to improve the
fuel flexibility of SOFCs.