Post 8 : Fuel Cell

Fuel  Cell

1. PEMFC 

     Fuel cell is an electrochemical device that generates electricity by combining hydrogen(H2) and oxygen(O2). If you want to keep a fuel cell generating electricity, just add more H2 and O2 to it. In other words, fuel cells won't go die, as long as we supply gas to them. Let's us look at the most promising kind of fuel cell, Polymer Electrolyte Membrane Fuel Cells (PEMFC). Among all fuel cells, PEMFC is more likely to be commercialized. The picture below shows a PEMFC's stucture.

pic. 1

 

2. How it works

     1. electrode : The anode conducts the electrons, so that they can go to the external circuit.

                           The cathode conducts the electrons back from the external circuit to the catalyst.

    

     2. electrolyte : In a PEMFC, the electrolyte is the proton exchange membrane. It only allows positively charged ions to go through. In this case, the proton exchange membrane let protons(H+) move from anode to cathode, and keep electrons from going into eletrolyte.

 

     3. catalyst : A catalyst is a substance whuch, without itself changing, quickens chemical reaction.

 

 

     The reaction occuring in a PEMFC is given by the picture below.First, hydrogen gas enters anode. When a H2 molecule comes to catalyst, it splits into two protons and two electrons. Then, the electrons go to the external circuit, and the protons move toward cathode. When electrons come to cathode from the external circuit, they react with protons and O2 molecules and form water and heat. 

 

pic.2

 

 3. Hydrogen cars

      According to this video, the Honda FCX clarity has been driven by people in the U.S. and Japan, and it is now testing in some European countries. There is a term called "Fuel Cell Stack" in this video that might confuse you. Since a single fuel cell can only generate electricity of 0.7 volts which can only light up some small device like a bulb. To increase the voltage of the electricity generated, we let the cell stacked in series.
      There are lots of advantage of using hydrongen cars. They are efficient, quite and they don't have any emission. What's more, their performance is good. Take the Honda FCX clarity for example, it performs very well at its top speed of 100 miles per hour!!(based on the video)

 

 

referance :

pic.1 and pic.2 : drawn by me