| Comparing
the Effect of Electrical Load on a
Fuel Cell and Rechargeable Batteries |
|
Researched by Katie M.
|
|
The purpose of phase one of this experiment was to measure the electrical output of a hydrogen fuel cell at different load levels.
The purpose of phase two was to measure the electrical output of both Nickel-Cadmium and Nickel-Metal Hydride rechargeable batteries at different load levels.
The purpose of phase three was to compare the electrical output of a hydrogen fuel cell with the rechargeable batteries at different load levels.
I originally became interested in this area last year when I was reading a newspaper article saying that auto manufacturers might start making cars operated by fuel cells. That lead me to conduct a study to see if the electrical output of a fuel cell changed when operated at different temperatures. Following that series of experiments I became interested in fuel cell output under low and high load levels. At about the same time my brother was complaining about his rechargeable batteries not powering an electrical toy long enough. I decided to compare the fuel cell with rechargeable batteries.
The information gained from this experiment could
help consumers decide which rechargeable battery to purchase. It
could also help manufacturers decide whether a fuel cell would be preferable
to rechargeable batteries for a given load.
My first hypothesis was that the fuel cell would produce more electrical output as the load decreases. I based this on Mrs. Theresa Koehler, an employee for Pacific Northwest Laboratories, who told me via e-mail that fuel cells produce more electricity at higher load levels.
My second hypothesis was that the rechargeable batteries would produce more electrical output as the load decreased. I based this on an email from Mrs. Theresa Koehler, who told me that batteries can respond faster than fuel cells.
My third hypothesis was that fuel cells would have an overall greater electrical output than the rechargeable batteries. I based this also on a graph sent by Mrs. Koehler showing that fuel cells have a higher wattage per kilogram.
My fourth hypothesis was that the NI-MH rechargeable
batteries would have an overall greater electrical output than NI-CAD rechargeable
batteries.
I based this on a graph from Mrs. Koehler that showed
this with wattage compared to kilowatt hours.
The constants in this study were:
* The test group size
* The batteries
* The fuel cell
* device to recharge the batteries and the fuel cell
* The room that the experiment takes place
* The temperature that the experiment is conducted
* The type of battery
* The type of fuel cell
* The type of fuel used in the fuel cell
The first manipulated variable was the amount of electrical load that the fuel cell powered.
The second manipulated variable was the type of rechargeable battery.
The third manipulated variable was the amount of electrical load that the rechargeable batteries powered.
The responding variable was the electrical output of the fuel cell and the rechargeable batteries.
To measure the responding variable I will use a computerized voltage probe made by Vernier Company and Logger Pro 3.0 software
| QUANTITY | ITEM DESCRIPTION |
| 1 |
Hydrogen fuel cell |
| 4 |
AA Nickel Cadmium batteries |
| 4 | AA Nickel Metal Hydride batteries |
| 1 |
probe |
| 1 | room |
| 2 | 1.5v light bulbs |
| 1 | computer |
| 1 | 23 x 4 3/4in board |
| 1 | Logger pro disk |
| 2 | light bulb holders |
| 2 | terminal strips |
| 1 | 6 x 3 in stick of metal. |
| 3 | toggle switches |
| 1 | Knife Switch |
| 1 | battery holder |
| 1 | roll of split telephone wire. |
| 1 | solar panel |
| 1 | 100 watt lamp |
| 1 | AA Ni-Cad and Ni-MH safe battery charger |
| 8 | Alligator clips |
PREPARTION PHASE
1. Assemble the board
a. Screw the battery holder to one end of the board.
b. Put two wire leads to the ends of the holder.
c. Screw the knife switch onto the board and then
attach the leads to the switch.
d. Put two wire leads on the other end of the knife
switch.
e. Attach a Thamas Komos multimeter (set to 200ma)
to one lead.
f. Attach the terminal strips to the board opposite
of each other.
g. Attach the other metal probe on the multimeter
to one of the terminal strips.
h. Attach the light bulb holders in a row at the
end of the board.
i. Put the correct light bulbs into the
holders.
j. Put 4 pieces of wire onto both terminal strips.
k. Attach alligator clips on to all 8 pieces of wire.
2. Set up the logger pro and Vernier volt probe
a. Install Logger Pro 3 into a strong computer.
b. Set the time to 2 hours and record 60 times an
hour
c. Put in the desired battery and number of
light bulbs.
d. Attach the probe to the computer and to channel
1.
I. Phase 1: Fuel Cell
1. Get the fuel cell ready.
a. Take off the protector tubes on the side.
b. Use the syringe to pump water through the side
of the cell.
c. Stop when you put one ml of water into the cell.
d. Put 47 ml of water into the container that holds
the gas containers. Shine a lamp straight onto the middle of the solar
panel, with the panel flat, to break the water a part until the gas containers
have gas bubbles coming out of the top.
2. Do test one with load of 1 small flash light bulb
a. Start the collecting. Use a multimeter to measure
the amperage.
b. Conduct trial two. Use the same directions above
(1a - 1d and 2a)
c. Conduct trial three. Repeat step 2b.
d. Conduct trial four. Repeat step 2b.
3. Do test with load of 2 small flashlight bulbs
a. Repeat steps 1a-2c.
II. Phase 2: NI-CAD
1. Do test one with 1 flash light bulb
a. Start the stopwatch. Use a multimeter to measure
the output of the cell every minute. Stop when the battery runs out of
energy.
b. Conduct another trial. Use the same directions
above.
c. Charge the battery for seven hours.
d. Conduct the final two trials of this load.
2. Do test two with 2 flash light bulb
a. Repeat steps 1a-1d.
III. Phase 3: Ni-HM
1. Do test one with 1 flash light bulb
a. Start the stopwatch. Use a multimeter to measure
the amperage
b. Conduct another trial. Use the same directions
above
c. Charge the battery for seven hours.
d. Conduct another trial. Use the same directions
above
e. Conduct another trial. Use the same directions
above
2. Do test two with 2 flashlight bulb
a. Repeat steps 2a-2e.
The purpose of phase one of this experiment was to measure the electrical output of a hydrogen fuel cell at different load levels.
The purpose of phase two was to measure the electrical output of both Nickel-Cadmium and Nickel-Metal Hydride rechargeable batteries at different load levels.
The purpose of phase three was to compare the electrical output of a hydrogen fuel cell with the rechargeable batteries at different load levels.
The results of the experiment were that the Ni-HM batteries performed the best. They held an almost constant voltage throughout the 2 hour test. The fuel cell did the worst staying at about zero for the majority of the two hours. All of the batteries and the fuel cell did the best at lower load levels
See the table and graphs below
My hypothesis was that the fuel cell would produce more electrical output as the load decreases. The results indicate that this hypothesis should be accepted.
My second hypothesis was that the rechargeable batteries produce more electrical output as the load decreased. The results indicate that this hypothesis should be accepted.
My third hypothesis was that fuel cells would have an overall greater electrical output than the rechargeable batteries. The results indicate that this hypothesis should be rejected.
My fourth hypothesis was that the NI-MH rechargeable batteries would have an overall greater electrical output than NI-CAD rechargeable batteries. The results indicate that this hypothesis should be accepted.
Because of the results of this experiment, I wonder if the fuel cell would perform the same if I used regular drinking water in the fuel cell instead of distilled water. I also wonder if the amount of time I charged the fuel cell and the batteries affect the experiment. I also wonder what would happen if I used different brands of batteries. I especially wonder if using a bigger fuel cell would have made the experiment a better comparison test.
If I were to conduct this project again I would conduct
more trials. I might also try 2 more load levels. I could also record
data for more than 2 hours. I might try 5 hours. I would also record data
points less frequently so that my graphs would be easier to read.
ACKNOWLEDGEMENTS
I would like to thank the following people for helping
make my project possible:
* My parents for buying my materials and supporting
me
* My teachers for allowing me to miss some class
to work on this project.
* I would especially like to thank Mr. Newkirk and
Mrs. Helms for all of their hard work.
* Mr. McMillan for lending me the voltage probe and
logger pro.
* I would also especially like to thank my Dad for
all of this help this year and last.
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