Talk:Fuel cell
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[edit] Fuel cells vs batteries
"Fuel cells differ from batteries in that they consume reactants, which must be replenished, while batteries store electrical energy chemically in a closed system."
This distinction seems a little weak. Both batteries and fuel cells consume reactants. Most modern batteries cannot be replenished, but archaic ones like gravity cells could (replacing the anode and the electrolyte was routine).
Can someone clarify the distinction?Kurzon 00:10, 21 January 2007 (UTC)
From an intrinsic point of view, fuel cells and batteries are exactly the same: both generate compound by means of a chemical reaction, where the side effect is electricity and heat. But in reality comparing them is almost like comparing apples and oranges. Any weak distinction made, is only arbitrarily come up with a definition for fuel cell Vs battery. Exceptions to the definitions will arise. --Fieraloca 04:00, 7 February 2007 (UTC)
[edit] Electro-galvanic fuel cell
Electro-galvanic fuel cells have been used for decades for measuring oxygen concentration in a breathing mixture. Would a short description or a reference to the article / use be appropriate? Especially as to how the concentration of oxygen gives a difference in voltage, which is converted to a displayed oxygen concentration. --Seejyb 20:12, 20 May 2006 (UTC)
- They have their own article Electro-galvanic fuel cell--DV8 2XL 20:26, 20 May 2006 (UTC)
[edit] Removed image
Who removed the image from commons ? its a GFDL licensed image from the French wiki. Fuelcell.en.jpg Reg .Mion 05:46, 16 June 2006 (UTC)
[edit] water fuel cell
1989 A so-called water fuel cell is an unrelated claim of a perpetual motion device, which in fact was not claimed to function the way a fuel cell does.
If the water fuel cell has its own article it could be referenced on, it makes people more critical about real inventions and hoaxes, //Enron/Tesla Motors.Mion 16:31, 19 June 2006 (UTC)
- Wikipedia's job is not to make people critical of hoaxes. This belongs in the disambig page, which is why it was removed. Chris Cunningham 17:36, 11 August 2006 (UTC)
In which disambig page ? Mion 19:14, 11 August 2006 (UTC) , and read the first part of the sentence, If the water fuel cell has its own article it could be referenced on, the second part was my personal view. Mion 19:14, 11 August 2006 (UTC) thats why i put it back.
and another one, there are loads of patents given on the design, it has the design of a fuel cell, the fact that we didn't see one working , tja.Mion 19:14, 11 August 2006 (UTC)
- It isn't a real fuel cell, the disambig tag at the top of the page links to the article in question, and you haven't given a justification which fits with the goals of the project. It's pretty disingenuous of you to ask "which article" without actually doing a search for "water fuel cell". Chris Cunningham 21:53, 11 August 2006 (UTC)
ok, i missed the top link to the disamb page, and which article, did i ask you ? well , i think it still belongs in the history section of fuel cells, or are we making only an article about fuel cells that where succesfull ? in that case there is more to clean out. reg. Mion 23:24, 11 August 2006 (UTC)
- This article is about fuel cells which fit the description given in the intro, i.e. which take hydrogen and oxygen as fuels. The water fuel cell works the other way around, so it isn't a "fuel cell" as per this article. It is mentioned, in the disambiguation tag. It isn't part of the history of fuel cells as per this article. Chris Cunningham 07:22, 12 August 2006 (UTC)
Yes, which takes hydrogen and oxygen as fuels to create a current. see Reversible fuel cell. reg. Mion 11:26, 12 August 2006 (UTC)
- A speculative stub does not an argument make. Chris Cunningham 12:46, 13 August 2006 (UTC)
well, can the process be reversed in a fuel cell? Mion 13:45, 13 August 2006 (UTC)
First, the fact that the water fuel cell was granted a patent is absolutely irrelevant; in fact the patent was granted on the basis of construction of the invention, and not on whether the invention actually works.
Second, Nope, a fuel cell does not have to be used with H2 and O2 only, don't forget direct methanol fuel cells, solid oxide, etc etc etc. What characterizes the fuel cell is not the reactants it uses, but the exchange of protons between the cathode and the anode via dielectric media. --Fieraloca 04:15, 7 February 2007 (UTC)
[edit] DCFC
http://www.wired.com/news/planet/0,2782,69713,00.html Mion 13:12, 16 July 2006 (UTC)
[edit] Turning off vs. continuous operation
If the water is not evaporated quickly enough, it reduces efficiency, and if it is evaporated too fast, it can crack the fuel cell. So, if used in, say, an automobile, does it have to keep operating all the time even when the car is parked, or can it be shut down, unlike the ones used in the Apollo space missions? (Jim Lovell on Apollo 13 knew that if they shut down the fuel cells as Mission Control told them to, they could not be restarted.) GBC 17:21, 11 August 2006 (UTC)
- Yes, they can be started, but it will take some time before they operate at full efficiency (depending on type: SOFC take a full 8 hours!). More than cracking, the dry-out causes an increase in internal resistance (it just does not work), but such PEMFC systems usually come with an humidifier. As for the Apollo, they used quite primitive alkaline FC technology... I do not know the details, but they were probably short-lifespan gizmos (after all they had to last for a few days only) assembled thinking more about saving weight than flexibility in usage. Come think of it, there is at least one type that must be operated continuously, the PAFC (phosphoric acid): below 41˚C the acid solidifies, and good luck warming it up again... but PAFC are almost ignored nowadays.
Once the membrane is hydrated within the break-in period of a new fuel cell, full performane can be achieved within minutes. Continuous operation is not necesary. Water is not evaporated from a fuel cell; the gas diffusion layer moves the water into the flow field of the current collectors.--Fieraloca 08:34, 12 November 2006 (UTC)
It should be noted that start up time depends heavily on type of FC, modern PEMFCs can start within a few seconds. The startup time of a fuel cell system usually depends on time required to get the ion conductivity layer to produce adequate conductivity for the current required. Nafion, a popular material for PEMFC ion conductivity layer (electrolyte) can operate lower than 0 C (32 F). SOFCs need to reach about 600-800 C to start conducting ions for efficient operation.
[edit] Fuel cell definition
Oxford dictionary: • noun:
- a cell producing an electric current direct from a chemical reaction.
[[2]]Mion 11:52, 11 September 2006 (UTC)
- the indefinite article does not denote that any device matching that short description is a fuel cell, any more than a definition of a crow as a "black flying object" implies that cannonballs are crows. Consensus has been shown to be in favour of leaving this article only for devices matching the scientific definition of a fuel cell as a device which creates electricity through oxidation. Chris Cunningham 14:18, 11 September 2006 (UTC)
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- I cited a reference, the Oxford dictionary: can you give me an equal valuable reference on the scientific definition of a fuel cell ?
- If consencus has been reached, ok , where can i find it ? if not the first part of the article has to be rewritten.
- or the other way around, if i cant hold my argument i am going to revert it myself. Mion 14:29, 11 September 2006 (UTC)
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- Try some specific literature like "Fuel Cell System Explained" by Larminie and Dicks, it is a common textbook in the subject. You should find it in any university library.
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[edit] Need help in writing an article about Pure Hydrogen-Air Fuel Cell
Hi Mion or Anyone can help-- Please. . .
As ESL (English as second laguage) person I need help in writing an article on what I beleive it could be a break through in Fuel Cell research.
- I have found in the setting of embrittled aluminum as anode, stainless steel as cathode and water as electrolyte one can build Hydrogen-Air fuel cells; I have it test run for hundreds of hours, no membrane or catalyst required; This will be:
-
- The least expensive to build.
- CO and CO2 Immune.
If you can help me in anyway please foreward me a note at ephitran at gmail.com
Many Thanks.
Phi
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- My advice is that you get in touch with the electrochemistry department at your local university. Write them (in your own language) a short abstract about your experimental setup and analysis, and I'm sure they will either help you or tell you why your invention doesn't work (My guess is the power density is too low). You will need to have a peer-reviewed publication elsewhere before you can post an article on Wikipedia, since original research is not allowed here. Good luck. --PeR 09:19, 2 October 2006 (UTC)
You are talking about a galvanic cell. Yes, you can get a galvanic potential when you place certain dissimilar metals together e.g. zinc and copper. There's no particular use for such as power source in real life.--Fieraloca 08:29, 12 November 2006 (UTC)
[edit] CHP efficiency
The paragraph about combined heat and power (CHP) appears to contain contradictory information. It states that fuel-to-electricity conversion is "typically 15-20%". Toward the bottom of the same paragraph, however, it states that PAFCs, which dominate the CHP market provide electric conversion efficiencies typically around 45-50%.
I don't know which range of numbers is more accurate, but it would seem that at least one of them is wrong. --jfinlayson 10:59, 18 October 2006 (UTC)
[edit] Proposed correction to Fuel cell issues
"Water management (in PEMFCs). In this type of fuel cell, the membrane must be hydrated, requiring water to be evaporated at precisely the same rate that it is produced. If water is evaporated too quickly, the membrane dries, resistance across it increases, and eventually it will crack, creating a gas "short circuit" where hydrogen and oxygen combine directly, generating heat that will damage the fuel cell. If the water is evaporated too slowly, the electrodes will flood, preventing the reactants from reaching the catalyst and stopping the reaction. Methods to dispose of the excess water are being developed by fuel cell companies."
Fuel cells virtually never run at an ideal condition, where "the same amount of water generated is PRECISELY evaporated". The gas diffusion layers (GDL) take care of the water management. If you have ever ran a fuel cell, you would know that the excess water is continuously discharged through the cathode side. --Fieraloca 08:17, 12 November 2006 (UTC)
[edit] Propose to modify chart
Propose to remove Metal Hydride Fuel Cell MHFC and Direct Boro-Hydride FC from the chart of different types of fuel cells.
Metal hydrides and Sodium-Borohydrides are HYDRIDES not fuel cells. They are H2 storage media. The H2 obtained from these two types of hydrides are usually fed into PEMFC.--Fieraloca 08:21, 12 November 2006 (UTC)
[edit] Correction to fuel cell efficiency
Using cell voltage as an indicator of efficiency is the biggest non-sense that I have ever heard!!!
Example: Take a perfect fuel cell; at an open cell potential of 1.23V, the current is Zero, thus the amount of H2 consumed is also Zero. Which means that you have just invented a perpetual motion machine, no need to feed H2, just 1.23V of pure Potential?!?!?
The efficiency of a fuel cell has to be measured as a ratio between the amount of energy obtained Vs the total enthalpy differential. Or other methods would also be fine.
--Fiera 08:52, 12 November 2006 (UTC)
In calculus there is the idea of limits. The open cell potential is always an ideal approximation - you measure it with a multimeter that draws a few picoamps, never 0. Similarly, the amount of H2 consumed due to these picoamps is a few femtomoles, which is still quite a few atoms considering avogradro's number is about 6x1023. When you talk about voltage, or potential energy in general (voltage in an electric forcefield, height/pressure/liquid head in a gravitational forcefield, pressure/spring constant in an electric forcefield between atoms), you always talk about rate of change, energy gained vs. distance traveled, motion. It's how much energy I would get per foot if I traveled north down this hillisde, there is an idealized answer to that, similarly like there is an idealized answer to an open cell potential, how much energy you would get per electron flowing through your wire, how many volts it carries. But you don't actually get any energy if you don't take a step, just sit still. Measuring the energy you have to move by a millimeter down the hillside, record the results to calculate how much you would get per meter. Similarly, if I have a pipe with 20 psi pressure of water meaning each cubic centimeter could give me such and such energy if I let it flow through my turbine/electric generator, the higher the pressure the more energy I'd get per cc of liquid. Staring at the pressure gauge on the pipe expressing to me the "pure potential" does not mean I have a perpetual motion machine because nothing is moving. In fact all pressure gauges obtain their reading by moving, whether a few millimeters against a spring load, or a few nanometers against a piezoelectric membrane. Sillybilly 13:12, 12 November 2006 (UTC)
Uhm... yea... i think i was being sarcastic when I said I invented the perpetual motion machine. What I am referring to is the following quote from the main fuel cell page, under "efficiency":
The efficiency of a fuel is very dependent on the current through the fuel cell: as a general rule, the more current drawn, the lower the efficiency. A cell running at 0.6V has an efficiency of about 50%, meaning that 50% of the available energy content of the hydrogen is converted into electrical energy; the remaining 50% will be converted into heat. For a hydrogen cell the second law efficiency is equal to cell voltage divided by 1.23, when operating at standard conditions. This voltage varies with fuel used, and quality and temperature of the cell. The difference between enthalpy and Gibbs free energy (that cannot be recovered) will also appear as heat.
What I'm saying is that this entire parragraph is pure non-sense. Whoever wrote this believes that the current stays constant with changing cell potential, that energy is measured in Volts, and that the open cell potential would yield a perpetual motion machine. Paragraph will be deleted unless objected by anyone. --Fieraloca 04:45, 7 February 2007 (UTC)
[edit] The Birth of the Fuel Cell - But Who is the Father?
One cited article [4] in the history section claims that the fuel cell was not invented by Groove in 1839, but by Schoenbein, and that Groove did not build a fuel cell until 1842.
Most fuel cell related articles, in the "background" or "history" section will cite Groove as the inventor and the year as 1839. (See, for example, [5] or [6])
Does anyone know the truth behind this? I think the article needs to be clarified.
--PeR 12:31, 29 November 2006 (UTC)
[edit] Vehicles
There is mention of cars and other vehicles that use fuel cells but not other vehicles. Perhaps there should also me mention of the first space craft. This submarine also uses Fuel Cells. I do not know if there were any before it. http://en.wikipedia.org/wiki/Type_212_submarine
Yewenyi 04:12, 6 December 2006 (UTC)
[edit] Current or Voltage
Consider the following section:
The efficiency of a fuel is very dependent on the current through the fuel cell: as a general rule, the more current drawn, the lower the efficiency. A cell running at 0.6V has an efficiency of about 50%, meaning that 50% of the available energy content of the hydrogen is converted into electrical energy; the remaining 50% will be converted into heat. For a hydrogen cell the second law efficiency is equal to cell voltage divided by 1.23, when operating at standard conditions. This voltage varies with fuel used, and quality and temperature of the cell. The difference between enthalpy and Gibbs free energy (that cannot be recovered) will also appear as heat.
This is confusing. Firstly, it says the efficiency is current dependent. Next, it gives an estimate of efficiency for a particular voltage. This needs to be clarified.
Ordinary Person 06:28, 6 December 2006 (UTC)
Paragraph should be deleted. Inaccuracies cited under discussion --- Correction to fuel cell efficiency ---
Fuel cell efficiency is dependent on several factors (stoichiometric flow of reactants, recirc vs non-recirc systems, parasitic loads, humidification of reactants, cell impedance and resistance, diffusion properties of the microporous layers, catalyst activity, etc etc etc. Voltage alone says nothing.--Fieraloca 04:54, 7 February 2007 (UTC)
[edit] $30/kWh
Someone wrote that it would be reduced to $30/kWh. If you read the reference closely, that's not what it actually says. I'll correct this, but I thought I'd note it here too.
[edit] New fuel cell developed
It is a simpler design and is more efficient. It is expected to first be incorporated in smaller engines like those found in lawn mowers. That should make in impact, since they are not regulated.[7] Brian Pearson 23:05, 16 January 2007 (UTC)
[edit] Micro fuel cell demonstrated by Japan Steel Works at FC Expo 2007
Take a look at [8]. DFH 20:31, 8 February 2007 (UTC)
[edit] Future technology?
New offshoreship with FC tech coming soon [9] --OddMartin 23:42, 22 February 2007 (UTC)
