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Conduction is the process which dictates the transport of charges through the fuel cell layers, except for the membrane. That means that the lack of adequate contact between the diffusion layer, bipolar plates and cooling plates is the cause of most of the ohmic losses outside of the membrane. There is where most of the overall ohmic loss occur. To help solving that problem, either the membrane needs to be made thinner, or its material needs to be more conductive. History and tests given that, have told us that making the membrane thinner is easier than the alternative. The challenge with making the membrane material more conductive balancing that property with its thermal and chemical stability.  The image below describes the relationship between membrane thickness and local conductivity: Source: SPIEGEL, Colleen.  PEM Fuel Cell Modeling and Simulation Using MATLAB ® .  Burlington, MA, USA: Academic Press, 2008. 440 p.

California dominates the scene when it comes to having hydrogen fuel cell refueling stations in the United States. In 2013, the New York Times reported 10 stations in the country, with one located in Columbia, SC, eight in Southern California and one in Emeryville. In 2016, that number increased to 31 stations in the US, with California having the most of them (28). Iceland used to have a refueling station for three buses for the public transport of Reykjavik, which operated from 2003 to 2007.  The station had the capacity of generating its own hydrogen through a electrolyzing unit. Japan is one of the countries with the greatest number of hydrogen fuel cell refueling stations. Up May 2017, they had 91 stations. Sources:  Berman, Bradley. "Fuel Cells at Center Stage" , New York Times, 24 November 2013, p. AU1.   Alternative Fueling Station Counts by State , Alternative Fuels Data Center, accessed December 2, 2016.   ECTOS 2003-7" , Icelandic New Energy, acces

For a fuel cell to run efficiently, there needs to be proper control of its temperature and heat generation. Some fuel cells work well in room temperature, but others require temperatures as high as 1000 ºC, and any value outside of the accepted range results in lowered efficiency of the device. Higher temperatures lead to faster kinetics and voltage, and lower temperatures cause shorter warm-up times, lower thermodynamical stresses and retardation of corrosion and other temperature-dependent processes. For fuel cells, higher temperatures also mean greater vaporization of the liquid water and, as a result, more of the waste heat becomes the latent vaporization heat.  The temperature profile in a fuel cell is ever-changing, even when the flow rate of the gases is constant. That happens because of the transfer of heat and phase change of some reactants. The accurate prediction of the temperature and heat distribution is essential to determine temperature-dependent parameters and r

The main objective when design flow fields is balancing the pressure drop and the amount of gas that is distributed to the GDL and catalyst layers. Parallel, serpentine and interdigitated designs are the most popular for fuel cell channels. In relatively small fuel cells, the serpentine design is usually used because the hydrogen reaction is not rate limiting and water blockage in the humidified anode can happen. In the image below, you can see a serpentine flow field design. The flow path is continuous and relatively efficient in distributing gas across the fuel cell. However, since the path is longer than in other designs, pressure loss might be a problem. One advantage of the design if that a block in the path does not compromise activity downstream. A disadvantage is that more gas needs to be input into the fuel cell because the design favors the depletion of the components. Another disadvantage is the build up of water in the cathode during extended periods of operation of

Although fuel cells were not investigated much during the 1800s and 1900s, the credit for the invention of the first fuel cells goes to William Grove. Intensive research on the topic began in the 1960s with NASA and only recently has commercialization of the technology begun to be conceivable. The image below is a summary of the history of the fuel cells. Before William Grove had invented the first fuel cell in 1839, William Nicholson and Anthony Carlislie came up with the process of using electricity of break water into hydrogen and oxygen in 1800. Willian, then, based his first fuel cell on their discovery. The device, called the gas battery or "Grove cell", was a combination of " electrodes in a series circuit, with separate platinum electrodes in oxygen and hydrogen submerged in a dilute sulfuric acid electrolyte solution" and it generated 12 amps of current at about 1.8 volts.  NASA began research on fuel cells for Project Gemini, which employed th