Week 2 Challenge

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

Answer:

The four types of fuel cells are:

• Polymer Electrolyte Membrane Fuel Cell (PEM)
• Alkaline Fuel Cell (AFC)
• Direct Methonol Fuel Cell (DMFC)
• Solid Oxide Fuel Cell (SOFC)

	PEM	AFC	DMFC	SOFC
Power	0.01 - 250	0.1 - 50	0.001 - 100	0.5 - 2000
Efficiency	40-55%	55-70%	40%	40-72%
Operating Temperature	60-110	70-130	70-130	500-1000
Electrolyte	proton-conducting polymer membrane	aqueous Potassium Hydroxide	Nafion	Ceramic electrolyte
Fuel	Hydrogen	Hydrogen	Methanol	Hydrogen
Byproducts	Water and heat	Water	Water and CO2	Water
Reactions	At anode: At cathode: Overall reaction :	At anode: At cathode: Overall reaction:	At anode: At cathode: Overall reaction:	At anode: At cathod: Overall reaction:
Applications	Mobile, Low power generation	Space, Military	Mobile, Portable	Vehicle Auxillary Supply unit, Medium to Large scale power generation

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, fuel cell.

Answer:

The above graph shows the energy density and power density of capacitors, Supercapacitors, Batteries and Fuel cells. From the graph, it is evident that the Fuel cell have the Highest Energy density and Batteries are in between the Super capaciters and Fuel cells. Whereas, Fuel cell have the Lowest Power density and Batteries are in between the Super capaciters and Fuel cells.

The above graph shows energy density and power density of battery types like lithium ion, lead acid, Nickel Cadmium, Ultracapacitor, fuel cell.battery types like lithium ion, lead acid, Nickel Cadmium, Ultracapacitor, fuel cell.

Fuel cell has highest energy density which means we can travel long with a fuelcell equipped electric vehicle but it consist of lowest power density which result in slower acceleration and vehicle runs under a speed limit. Ultracapacitors have highest power density but lowest energy density and can not be used as standalone fuel source. it is either used with fuel cell or li-ion batteries. When compared to ultra capacitor, lead acid battery has higher energy density but low power density which means it has capacity to run a vehicle upto a distance bus has less power. Li-ion is most suitable and more economical for every pupose and every voltage rating it is used in combination of series and parallel to carry out the required voltage rating. Nickel Cadmium are better than lead acid battery but in comparision to the li-ion batteries they are similar or we can say as near as lead acid batteries.