What is Fuel cell: Definition and 57 Discussions

A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, whereas in a battery the chemical energy usually comes from metals and their ions or oxides that are commonly already present in the battery, except in flow batteries. Fuel cells can produce electricity continuously for as long as fuel and oxygen are supplied.
The first fuel cells were invented by Sir William Grove in 1838. The first commercial use of fuel cells came more than a century later following the invention of the hydrogen–oxygen fuel cell by Francis Thomas Bacon in 1932. The alkaline fuel cell, also known as the Bacon fuel cell after its inventor, has been used in NASA space programs since the mid-1960s to generate power for satellites and space capsules. Since then, fuel cells have been used in many other applications. Fuel cells are used for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. They are also used to power fuel cell vehicles, including forklifts, automobiles, buses, boats, motorcycles and submarines.
There are many types of fuel cells, but they all consist of an anode, a cathode, and an electrolyte that allows ions, often positively charged hydrogen ions (protons), to move between the two sides of the fuel cell. At the anode a catalyst causes the fuel to undergo oxidation reactions that generate ions (often positively charged hydrogen ions) and electrons. The ions move from the anode to the cathode through the electrolyte. At the same time, electrons flow from the anode to the cathode through an external circuit, producing direct current electricity. At the cathode, another catalyst causes ions, electrons, and oxygen to react, forming water and possibly other products. Fuel cells are classified by the type of electrolyte they use and by the difference in startup time ranging from 1 second for proton-exchange membrane fuel cells (PEM fuel cells, or PEMFC) to 10 minutes for solid oxide fuel cells (SOFC). A related technology is flow batteries, in which the fuel can be regenerated by recharging. Individual fuel cells produce relatively small electrical potentials, about 0.7 volts, so cells are "stacked", or placed in series, to create sufficient voltage to meet an application's requirements. In addition to electricity, fuel cells produce water, heat and, depending on the fuel source, very small amounts of nitrogen dioxide and other emissions. The energy efficiency of a fuel cell is generally between 40 and 60%; however, if waste heat is captured in a cogeneration scheme, efficiencies of up to 85% can be obtained.

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  1. J

    Fuel Cell Reaction Question - is this right?

    The quantity (dE_dP)_T can be derived using the Gibbs-Helmholtz equation which states that dE = TdS - PdV + μdN where E is the internal energy of the system, S is the entropy, V is the volume, N is the number of particles and μ is the chemical potential. Differentiating this equation with...
  2. E

    Reversible operation of fuel cell

    Can someone explain me what does the underlined part of the following passage mean? "The reversible operation of a fuel cell implies that the external circuit exactly balances its emf, with the result that its current output is negligible. In actual operation under reasonable load, internal...
  3. J

    Understanding the chemical process in a fuel cell

    Hello, I'm taking an energy class and I'll be giving a presentation on fuel cells. I was wondering if I could get some help understanding the whole process of the paper below. Unfortunately, I can't post the article because of copyrights. To summarize, it's a one compartment H2O2 fuel cell with...
  4. S

    Hydrogen to AC -- From the Fuel Cell to the Grid

    Fuel cells quickly provide electricity from H2 when switched on. But what exact steps get to Grid voltage? Are there many small inverters, and if so, how do they keep the output in step? What sort of efficiencies are there?
  5. A

    Fuel cell mass flow rate magnitudes

    Hello, Can you tell me please the mass flow rate of hydrogen and oxygen per unit of area of electrodes in fuel cells? Or if you have information on the mass flow rate of hydrogen and air per volume of fuel cell stack? I understand this may vary, but I am looking for publications or other...
  6. srinaath

    Why do we need to supply air to the cathode of a hydrogen fuel cell

    I am trying to understand the working of simple hydrogen fuel cell. We have anode (negative terminal), cathode (positive terminal), catalyst at anode to separate negative and positive ions of hydrogen atoms and electrolyte which allows only positive ions. We will be sending hydrogen fuel at...
  7. S

    Simulink model of a hybrid vehicle (replace battery with fuel cell)

    greetings, here I found a Simulink model on mathswork, I want to replace the battery with a fuel cell, so I'm stuck at the level of the energy management block. here is the link of the model: https://www.mathworks.com/matlabcentral/fileexchange/28441-hybrid-electric-vehicle-model-in-simulink...
  8. J

    Microbiological Fuel Cell: Negative Voltage

    Hello! I've been working on a few soil based MFCs and I have been monitoring my voltage and energy output for a week now. I've made the electrodes by covering stainless steel metal meshes with activated carbon using epoxy. I've gotten some funky results as attached. As you can see... the...
  9. D

    Getting rid of fuel cell / flow battery membrane

    I am aware of laminar flow but would like to look for some other ways. Is it possible to block ions from flowing in the "wrong" direction by applying a magnetic field to the electrolyte and let neutral molecules pass through?
  10. Jamison Bond

    HHO Easy Recombination to get electricity

    I was just wondering if there is an easy way to recombine hydrogen in a fuel cell style but effectively by doing electrolysis in reverse. Splitting is really easy but is there a way to get the HHO to recombine into water and release electricity effectively by reverse electrolysis? I get that...
  11. Thermo

    Fuel cell voltage end efficiency

    I know theoretically fuel cell efficiency decreases as temperature increases. But in practice it is vice versa. What is the reason of that? I couldn't find enough sources. Any kind of help is much appreciated.
  12. Z

    What is the forefront of research in energy?

    Essentially, I'm wondering (knowing virtually nothing at present), what is at the front of modern research in the realm of energy. Whether this be renewable energy, or simply more efficient ways of using energy (e.g. fuel cells?). I assume nuclear fusion will be mentioned too, so what obstacles...
  13. C

    Effect of Air temp on fuel cell

    Hi! Recently, I got a hobby grade mini- fuel cell after watching a youtube video. Sometimes the fuel cell doesn't perform steadily. What effect does the surrounding air temperature have on PEMs? will it work better if i run in near an AC? (:wink:) I've seen some really complex images on...
  14. 0

    Application of Series/Parallel connection of DMFC? (Direct Methanol Fuel Cell)

    Hello, Just as the title asks, what sort of applications would series and parallel connections of Direct Methanol Fuel Cell suit the best? Based from my understanding of Fuel Cells and experimental results, one cell is not enough to power anything, hence they are used in stacks, in addition...
  15. M

    Fuel cell open circuit voltage and pressure of reactants

    Hello, I have some questions regarding the nernst equation at open circuit voltage. We know E(OCV) = E0+ ln (PH2*PO2^0.5 / PH2O) I have some trouble with this: If I have dry gas (both for O2 and H2), and my circuit is open at 25°C and 1 atm I have no water in the circuit so what become the...
  16. C

    Surface area contact with catalyst effect on hydrogen redox

    I have also posted this question here: Relationship between surface area of electrode and reaction rate of hydrogen in fuel cells, but I really need an answer before tomorrow morning so I hope you don't mind me posting it here as well! I am looking at the effects of increasing the surface area...
  17. C

    Fuel Cell Collector: Optimizing Flow & Pressure

    Hi, I haven't posted anything on here in a long time, but thought somebody here could help me out. I am building a fuel system for an endurance sports car. I have a sealed 0.6 gallon collector in the fuel cell with three 75gph pumps, capable of 95psi feeding it, through 3/8" hose. It then...
  18. K

    Need to Find OCV for H2O2 Fuel Cell

    Homework Statement Calculate the open cell voltage for an H2/O2 fuel cell operating at P=1atm and T = 100°C Homework Equations Nernst Eq: Eo+(RT/nF)*ln[(aH2)*(aO2^1/2)/(aH2O)] The Attempt at a Solution E=1.17V+((8.314J/mol-K)*(373K))/((2e-)*(96486C/e-))*ln[(PH2*PO2^1/2)/PH2O]...
  19. P

    Help in fuel cell main references

    Hi As I am preparing for a presentation about modern http://scopewe.com/tag/fuel-cell-2/ I need some reference books or articles about fuel cells and the technology of these cells. I appreciate any information about these cells: 1.Solid oxide fuel cell (SOFC) 2.Alkaline fuel cell (AFC)...
  20. 4

    Natural Gas to generate hydrogen, fuel cell?

    Hi all, one last question for today - Given steam reforming of natural gas to generate hydrogen, what is the major difficulty with it with respect to most fuel cells? Thank you,
  21. 4

    Fuel Cell, Etn, Er and polarizations

    Can anyone help me explain the elements of the fuel cell polarization curve. Please be sure to include Etn, Er, and the various polarizations. I am interested by the use of thermodynamics as well... Thank you-
  22. R

    Is a fuel cell technically an energy storage device?

    I've heard fuel cells being called energy storage devices. However, unlike batteries, they only convert energy. They don't store anything unless you consider the brief moment of converting chemical energy to electrical energy storage time? Are there fuel cell types that store let's say hydrogen...
  23. A

    Fuel Cell with unpressurised Hydrogen and Oxygen

    Let's say I have a balloon full of Hydrogen that is STP, and outside this balloon I have normal air (containing oxygen) which is also STP. Is there a way to produce energy by turning these 2 items into a fuel cell, if so how practical is it (in a DIY setting) and is there anything that would...
  24. F

    Gasoline fuel cell (vs. gas generator)

    Fuel cells means chem engineering, right? (move to the right section if necessary) Anyway this sounds great, except that it still uses gasoline: http://www.technologyreview.com/energy/39203/
  25. L

    Understanding Free Energy in Fuel Cell Reactions

    I'm given a fuel cell that uses methane as fuel: (CH4) + 2(O2) --> 2(H2O) + (CO2) And I'm asked to find (a) the electrical work I can get out for each mole of methane, and (b) the amount of waste heat produced. I understand that ΔG is defined as the amount of useful non-mechanical work...
  26. M

    PEM Fuel Cell: Hydrogen Ion Diffusion Through Anode?

    Hey everyone, I was just wondering, in a PEM fuel cell the Hydrogen ion diffusion through the membrane is an important step. But don't these ions need to diffuse through the anode as well to reach the membrane? Also, if this is the case and the anode is a metal like Pt, wouldn't the diffusion...
  27. baywax

    Is there a way to replace nuclear power with a (big) hydrogen fuel cell

    Could one really big hydrogen fuel cell battery replace a nuclear reactor in providing power to millions of people? This may end up being a safer option for generating power.
  28. C

    Is it Possible to Build a Direct Borohydride Fuel Cell

    Basically as the title says, is it possible to build a DB fuel cell stack? Something that could output 100W (to power a laptop or for power outages). I actually have access to a couple of kilos of sodium borohydride and while looking at what I can do with the stuff I came across this type of...
  29. O

    Generating Electricity with HHO Gas: What Fuel Cell?

    Is there a way to make the atoms in HHO gas (Browns gas) to separte into it's elements; so the Hydrogen atoms go one way and the Oxygen in another way. By doing this I'm hoping to generate electricity from the reaction by bringing them together again. What kind of fuelcell do I need?
  30. S

    Fuel Cell Efficiency: Average Output for Cars, Homes, & More

    I understand that generating the hydrogen that powers a typical fuel cell is (prohibitively?) energy intensive at this point, but I was curious about the following: Assuming a sufficiently efficient catalyst was obtained that allowed large-scale production of pure hydrogen without...
  31. Saladsamurai

    Where Does Platinum Fit in Hydrogen Fuel Cells and Electrolysis?

    Hey folks, I am currently doing some research on hydrogen fuel cells as part of a project. I just wanted to clear up some confusion I am having with the whole *platinum issue.* Very generally speaking, this is what I have gathered on H2 Fuel cell vehicles: 1) Electrolysis is needed to...
  32. P

    Thermal Physics - Methane Fuel Cell

    I think I got a and b, the rest I did my best on, and I could use some guidance! Thanks!Homework Statement 1. [6] Methane (Natural Gas) Fuel Cell. Consider a fuel cell that uses methane as fuel. The chemical reaction is CH4 + 2O2 = 2H2O + CO2 + energy (a) [0.5] Measurements reveal that...
  33. C

    How to Calculate the Theoretical Voltage of a PEM Fuel Cell?

    Hi, I'm working on a commercially available PEM fuel cell and I'm trying to calculate the theoretical voltage of the cell: The only electrochemical reaction considered is H2 + 0.5O2 --> H2O And I understand that I need to use the Nernst equation: E = EO - (RT / 2F) ln (PH2O / (PH2 *...
  34. S

    Fuel cell stack model in femlab 3.1

    i am learning femlab 3.1...so following the model library given with the set of books.. but i am facing problems with the 3 d modelling.. as in case of fuel cell stack model..the solver is unable to solve even if all the steps are followed according to given instructions.. i have double...
  35. H

    Conversion of Internal Combustion Engine Vehicle to Hydrogen Fuel Cell Vehicle

    I’m from a group that is current working on the theory of a Hydrogen Economy. Our first area of development is the Hydrogen Highway. We are currently seeking help in the form of freelance / work for hire basically engineer(s) that could aid in design and calculations of internal combustion...
  36. C

    Understanding Nernst Voltage in Fuel Cells at High Temperatures

    Hello, I'm doing work in Fuel Cells and am having difficulty with a simple issue; the Nernst Voltage (E) is greater than the Standard Potential (EO) The only electrochemical reaction considered is H2 + 0.5O2 --> H2O The Nernst equation for this reaction is E = EO - (RT / 2F) ln (PH2O / (PH2...
  37. E

    Impact of Temperature on Fuel Cell Work Output

    Homework Statement 2 H2(g) + O2(g) 2 H2O(l) K = 1.28e83 As temperature increases, does the maximum amount of work obtained from the fuel cell reaction increase, decrease, or remain the same? Homework Equations 1. G = -RTln(K) 2. dG = dH - tdS 3. w_max = dG The Attempt...
  38. S

    Question: Fuel Cell Thermodynamic Equations

    I'm an undergrad working on fuel cells for a project and I have been using a book to aid me. There are several equations in the book that were not explained properly so I was hoping someone on this forum could help identify how they were derived. The first 2 is related to the pressure within...
  39. mtworkowski@o

    Exploring Fuel Cell Technology for Improved Energy Efficiency in Automobiles

    I've heard about the units that run on DC and extract O and H from water. The gases are then used on automobles to increase fuel mileage. I'd like to hear the thoughts on energe in and energy out. Also, as hybrids store energy for a finite number of power demands, can these fuel cells do a...
  40. N

    Fuel Cell Engineering: Pursue Education or Job After Physics Major?

    I have just finished my sophomore year at Columbia University with a major in physics. I chose Columbia College instead of the engineering school due to the better reputation/ranking and I was not sure whether to go into physics or engineering. However, after two years of courses, I am very...
  41. Greg Bernhardt

    Why aren't hydrogen fuel cell cars more popular than conventional batteries?

    Enuma's thread got me thinking why these isn't more buzz for the hydrogen cars like the Honda FCX, GM Sequel, Nissan Frontier, BMW 7...
  42. S

    Maximum Useful Work from a Fuel Cell

    What is the maximum useful work which can be obtained from a hydrogen-oxygen fuel cell that produces 1.96 kg of water at 25°C? How do we approach this problem? I guess -Ecell x charge = w?
  43. R

    Efficiency of a hydrogen fuel cell

    I'm trying to calulate the efficency of a small hydrogen fuell cell that I built. I have all of the measurements, but I'm not coming up with a resonable effiency. The power to electrolyze the water is the P IN. 3.25 W =2.5 V x 1.3Amps (.21 mA) We measured the electrical power out...
  44. R

    Calculating the efficency of a hydrogen fuel cell

    Homework Statement I'm trying to calulate the efficency of a small hydrogen fuell cell that I built. I have all of the measurements, but I'm not coming up with a resonable effiency. Homework Equations \frac{P OUT}{P IN}x 100 The power to electrolyze the water is the P IN. 3.25 W...
  45. A

    How does a Betavoltaic Laptop Fuel Cell work?

    http://www.nextenergynews.com/news1/next-energy-news-betavoltaic-10.1.html I cam across this article. It is horribly written from a scientific standpoint and lacks some necessary information on how the device works. But the basics are... Tritium is the beta source, porous silicon matrix...
  46. C

    Need of information about a hydrogen oxygen fuel cell

    Can anyone tell me if it is right to say that maximum power of a hydrogen oxygen fuel cell varies directly (with constant efficiency) with gas flow rate at constant pressure at room temperature
  47. P

    Help with a Hydrogen Fuel cell presentation

    I need help thinking of ideas for slides. I have "How it works", "benefits", "challenges", "Physics behind it", "Hydrogen vehicles", "Why Hydrogen", "What is a fuel cell", "Uses", "efficiency", "Fuel cell configurations". I can't think of anything else.
  48. Z

    Generating Electricity with Hydrogen Fuel Cells

    In my school we are developing and investigating the process of generating electricity by means of an hydrogen fuel cell. We have started with an aqueous solution of NaCl and connect it to a 12 volt generator. Then, we waited for 3-4 minutes and disconnected it from the generator and connected...
  49. T

    Could a Microscopic Compound Solve the Storage Issue for Fuel Cell Cars?

    i recently read in a popular science magizine about a guy inventing a substance that was like a "scafalding" for atoms. that the atoms (gas state) bonded to this structure (assuming this scaffalding is microscopic) making it "semi-solid" i don't know what you would call it. but what if you did...
  50. B

    Making a Hydrogen Fuel Cell: Is it Possible?

    how do i make a fuel cell which utilises hydrogen and oxygen to make water and in the meantime give out loads of heat. is it possible?: