Week 2 Challenge

Question 1:
Compare four different types of fuel cells and state their applications.

Fuel cell type	Advantages	Challenges
Proton Exchange Membrane Fuel Cell (PEMFC)	- Solid electrolyte reduces corrosion and electrolytic management problems - Low temperature - Quick start-up and load following	- Expensive catalyst - Sensitive to fuel impurities
Solid Oxide Fuel Cell (SOFC)	- High efficiency - Fuel Flexibility - Solid electrolyte - Suitable for power and heating	- High-temperature corrosion and breakdown of cell components - Long start-up time - Limited number of shutdowns
Alkaline Fuel Cell (AFC)	- Wide range of stable materials allows lower-cost components - Low temperature - Quick start-up	- Sensitive to CO2 in fuel and air - Electrolyte management - Electrolyte conductivity
Direct Methanol Fuel Cell (DMFC)	- Ease of fuel delivery and storage - Low cost of Methanol - Operation at low temperatures and pressure	- Still emits CO2 - Sluggish kinetics of Methanol oxidation - Much slower than that Hydrogen - Methanol crossover reduces cell voltage

PEMFC stack PRAGMA industries

Solid Oxide Fuel Cell (SOFC): Bosch

Alkaline Fuel Cell (AFC)

Direct Methanol Fuel Cell (DMFC)

Question 2:
Using a plot with energy density and power density on the X and Y axis, arrange various battery types like lithium-ion, lead acid, Nickel Cadmium, Ultracapacitor, and fuel cell.

Energy storage device	Specific energy	Specific power
Lithium-Ion battery	100-265 wh/kg	250-340 w/kg
Lead acid battery	35-40 wh/kg	180 w/kg
Nickel Cadmium battery	40-60 wh/kg	150 w/kg
Ultracapacitor	0.5-30 wh/kg	Up to 10000 w/kg
Fuel cell	300-1000 wh/kg	10-210 w/kg

• The Ragone plot is very useful in determining the specific power and specific energy of energy storage devices.
• As we can see ultracapacitors are the best specific power devices, so it has the ability to charge and discharge very quickly which makes them very attractive to high-performance EV makers.
• Supercapacitors can operate at a temperature range of -40 to 100 Celsius
• Supercapacitors are designed to provide high power, long stability, and efficient storage.
• On the other hand, fuel cells are the highest specific energy devices but in the case of PEMFC - for example – the high cost of a fuel cell membrane is high, so research and development are there to reduce these costs.
• However, the power density of the fuel cell is much lower if compared to batteries and or ultracapacitors.
• Fuel cells win the debate of the charge/discharge time of the batteries if used in EVs 5 mins of refueling and range of 500KM approx.
• Battery recharging stations need a very strong infrastructure to be able to afford the very large load if many cars are charging at the same time, especially fast charging.
• But here’s the trade-off, Hydrogen refueling facilities and stations are very scarce in a country like Egypt almost no Hydrogen refueling station yet.