Fuel Cells

Topic and Area of Science

• Topic: Creating Energy From Fuel Cells

• Areas of Science: Chemistry, Physics, Engineering

• What is a fuel cell?• A fuel cell operates like a battery,

converting chemical energy directly into electrical and thermal energy. A fuel cell and a battery are similar in many respects.

Big Question

• Purpose (Big Question) Do fuel cells provide an efficient

form of energy?

Hypothesis

• Hypothesis Fuel cells do not provide an efficient enough

form of energy because if they did they would be used more widely today in cars, trucks, and other vehicles.

Interesting facts• A fuel cell is a device that generates electricity by a

chemical reaction.• Every fuel cell has two electrodes, one positive

electrode and one negative electrode cell.• A fuel cell has an electrolyte, which carries electrically

charged particals.• Hydrogen is the basic fuel to power a fuel cell but fuel

cells also require oxygen.• The five major types of fuel cells are alkali, solid oxide,

phosphoric acid, molten carbonate, and proton exchange membrane.

• Each one of the fuel cells listed above works a bit different from each other.

• Friedrich Wilhelm Ostwald (1853-1932), a founder of the field of physical chemistry, provided much of the theoretical understanding of how fuel cells operate.

Materials

• Materials– Fuel cell car kit– 5 AA batteries– Distilled water– Electrical tape– Two books 1 in thick– Computer– Computer paper– Pencils– Computer ink– Binder– Paper protectors

Procedures

• Procedures• Assemble Fuel Cell Car

– Body– Wheels– Motor Cover– Fuel Cell Membrane– Cylinders for Hydrogen and Oxygen Collection

• Charge Fuel Cell Using Electrolysis– Fill fuel cell with water– Connect fuel cell to gas collection cylinders– Connect battery pack to fuel cell– Convert water to hydrogen and oxygen– Measure the amount of time required to produce oxygen and hydrogen using electrolysis

• Measure the ratio of oxygen to hydrogen

• Measure Time to Drain Fuel Cell– Connect the fuel cell wires to the car motor and operate until fuel cell is drained– Record the amount of time the car operates before draining the fuel cell

Procedures

• Repeat steps 3 & 4 several times to break in fuel cell membrane• Measure the Impact of Friction on the Time to Drain the Fuel Cell

– Operate the car suspended in air, on hardwood floors and on carpet– Record the amount of time the car runs on each surface before draining the fuel

cell• Measure the Amount of Battery Power Used to Charge the Fuel Cell

Compared to Powering the Car– Get three new AA batteries– Using two batteries, perform steps 3 and 4 continuously until the batteries

cannot power the electrolysis– Record the total amount of time the car runs– Hook up the third AA battery to the motor wires using electrical tape

• Record the total amount of time the car runs

– Compare the time the car runs when two batteries are use to charge the fuel cell compared to one battery powering the motor directly

Control Group and Variable

• Control Group: Car running in air without friction

• Variable: Power source: (a) batteries or (b) fuel cell using hydrogen and oxygen produced from batteries

Data

Hydrogen Oxygen

1 1:45 3:14 5:40

2 0:49 1:46 5:26

3 0:48 1:45 3:20

Averages 1:07 2:15 4:48

1 0:49 1:47 0:47

2 0:53 1:54 2:05

3 0:54 1:58 2:07

Averages 0:52 1:53 1:39

Hydrogen Oxygen

Single Battery

10:49

Double Battery

21:38

Test #Fuel Cell Charge #

Power Source

Time to Fill Gas (hr:min)

SurfaceRun Time (hr:min)

Observations

2 Fuel Cell Rug

- The car moved much slower on the carpet- The car ran for less than half as long on carpet as on wood- The hydrogen container fills up in about 50 seconds on each run

3 Air

- The car ran continuously for almost 11 hours using a single AA battery for power when held up between two books- Two batteries were assumed to power the car twice as long as one battery- The car did not slow down at all until the last couple of minutes

Test #Power Source

Surface

1 Fuel Cell Wood

Run Time (min:sec)

ObservationsFuel Cell Charge #

- The hydrogen container filled up in half the time as the oxygen- When the car stopped all the hydrogen was used, but only half the oxygen was used- The car ran close to full speed all the way until the end

Time to Fill Gas (hr:min)

DataHydrogen Oxygen

1 0:45 1:07

2 0:47 2:40

3 0:48 3:46

4 0:52 4:05

5 1:00 4:54

6 0:58 4:06

7 1:03 4:18

8 1:01 3:31

9 1:04 3:52

10 1:06 4:28

11 1:08 2:52

12 1:10 3:42

13 1:10 3:22

14 1:07 2:41

15 1:12 2:58

16 1:09 3:08

17 1:02 3:11

Averages 1:01 3:27

Total 17:17 58:41

Fuel Cell Charge #

Run Time (hr:min)

Remaining 139 Runs 8:16

Overall Total

156 Runs 9:15

# of Times Hydrogen Cylinder Filled

SurfaceRun Time (min:sec)

Observations

4 Fuel Cell Air

- The car runs approximately the same amount of time suspended in air as it does on the wood floor- After 17 charges of the fuel cell to make hydrogen and almost 1 hour of runtime the car batteries did not show signs of weakening- The batteries were used to fill the hydrogen container another 139 times- The estimated additional run time was 454 hours and 42 minutes- The total run time using batteries to charge the hydrogen until they ran out of charge was 513 hours and 23 minutes

Test #Fuel Cell Charge #

Power Source

Time to Fill Gas (hr:min)

Analysis of Data

Fuel Cell Batteries0

5

10

15

20

25

Run

Tim

e (h

rs)

• The car ran over twice as long on batteries as it did using batteries to separate hydrogen and power the fuel cell

• It takes more energy to separate hydrogen than the hydrogen creates in a fuel cell

Batteries used to separate hydrogen and oxygen

Batteries used to power car directly

Analysis of Data

wood rug0:000:280:571:261:552:242:523:213:504:194:48 Hydrogen Charge Time

Oxygen Charge Time

Run Time

Tim

e (m

in:s

ec)

• The oxygen cylinder took twice as long to fill as the hydrogen

• The car ran three times longer on the wood floor than on the rug

• It took more energy to run on the carpet because of friction

Analysis of Data• The experiment tested my hypothesis because I was able to test the amount of time

the car ran on batteries alone compared to running on a hydrogen powered fuel cell.

• Since the batteries were used to separate the hydrogen I could tell which used more battery power, running the car or creating hydrogen to run the car.

• The batteries alone were able to run the car for 21 hours and 38 minutes while the fuel cell was only able to run the car for 9 hours and 15 minutes using the same amount of battery power.

• I also noticed that the car could only run for less than half as long on carpet than a wood floor or air because of the friction.

• I believe the experiment tested my hypothesis because there were no malfunctions with the experiment and the car operated the way the manual explained.

• Almost every time I used the fuel cell to separate the hydrogen it took just about a minute and filled up in about half the time as the oxygen. This makes sense because there is twice as much hydrogen in water as oxygen.

Conclusion

• My hypothesis was correct because it took more energy to make the hydrogen than the hydrogen created in the fuel cell. Therefore the battery by itself was a more efficient form of energy than when used to charge the fuel cell. The batteries ran the car for over twice as long as the fuel cell and hydrogen using the same amount of battery power. This is because it takes a lot of energy to make the hydrogen. This is probably why fuel cells aren't used more often.

• If I changed the experiment I would like to find out if there are more efficient ways to make hydrogen than by using the fuel cell. Maybe by trying solar power so the energy would be free. That would make the fuel cell more efficient than the batteries.

• Questions I would have are: What is the best way to get hydrogen? How expensive is it to make fuel cells? If cars all ran on fuel cells where would people get the hydrogen?

Fuel Cell Experiment Pictures

Fuel Cell Experiment Pictures

Bibliography

www.Alternativegassolutions.com http://americanhistory.si.edu/fuelcells/basics.htm http://americanhistory.si.edu/fuelcells/glossary.htm www.bcsfuelcells.com/index.htm www.fuelcells.org www.fueleconomy.gov/feg/fuelcell.shtml www.utefuelcells.com

Any Questions???Thank you for

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