Methanol fuel cells are divided into direct methanol fuel cells (DMFC) and recombinant methanol fuel cells (RMFC), which are mainly developed for portable devices such as mobile phones and notebook computers. Although the energy density of methanol fuel cells is not as high as other types of fuel cells, it has the advantages that methanol fuel is easy to carry and easy to store, so methanol fuel cells are more suitable for portable devices.
So far, no actual methanol fuel cell products have entered the civilian market. The development of methanol fuel cells is still underway. The research direction is mostly focused on the miniaturization of batteries, service life, energy density, and power efficiency. Improvements, it takes time for the methanol fuel cell to actually be mass-produced. In any case, most people think that methanol fuel cells will replace traditional batteries as the main power source for portable devices. It can be seen that in recent years, various manufacturers have successively launched their own prototypes/prototypes. This article roughly describes the principle of DMFC, and introduces RMFC from the defects of DMFC. Finally, several prototypes and products of RMFC are listed.
First, DMFC
In terms of technical principles, the DMFC is mature. It can generate stable energy immediately, and does not need to cool the battery body during the reaction; the methanol fuel used is easy to store because it is in liquid form, and does not condense in cold environments; it is safe in size and weight reduction. The DMFC is also easy to do. All these advantages make the DMFC more advantageous than other types of fuel cells in some applications. For example, we can see the DMFC in the household appliances such as lawnmowers and chainsaws, and we can also see the passenger liner. The store uses DMFC as a backup energy source, and the micro DMFC becomes an alternative energy source for portable devices. Figure 1 shows the DMFC-based music player from Toshiba.
The DMFC typically includes a permeable electrolyte membrane through which methanol passes through the anode of the DMFC and air passes through the cathode of the DMFC. The chemical reaction with methanol and air produces electricity, which does not burn and only produces CO2 and water. Methanol is decomposed into hydrogen atoms and CO2, and protons form H2O with O2 in the air, and electrons pass through an external circuit to reach the negative electrode of the film. The equation for the chemical reaction is as follows:
Full reaction equation:
CH3OH +3/2O2=CO2 + 2H2O
anode:
CH3OH + H2O=CO2 + 6H+ + 6e-
cathode:
3/2O2 + 6H+ + 6e-=3H2O
2. Defects of DMFC Electrolyte membranes of methanol aqueous fuel cells (DMFC) mostly use Perfluoro sulfone acid-based materials. Since this material forms a cluster inside, protons surrounded by water molecules can form a channel for proton hydrates. Therefore, the conductivity of the proton is very high, however, the same combination of methanol as the proton hydrate crosses the film and reduces the utilization of methanol. This is known as the crossover phenomenon of methanol. Once the methanol penetrates, it will be at the cathode. The catalyst reacts with oxygen, which causes problems such as voltage drop. Increasing the battery capacity is very effective using a high concentration aqueous methanol solution, but a high concentration aqueous methanol solution is also liable to cause methanol breakthrough. Therefore, the electrolyte membrane is required to have high proton conductivity, and it is also necessary to control the penetration of methanol. This is actually a fatal flaw in the DMFC. Hydrogen ions need to be carried by water through the polymer film. In order to avoid this situation, researchers have taken various other methods to prevent the penetration of methanol, such as increasing the isolation of methanol and high. The isolation layer of the molecular film, the use of a water-repellent gradient, and the like.
Another problem faced by the DMFC is the discharge of CO2. Although methanol can be supplied passively (ie, without the use of a pump), the accumulation of CO2 in the catalyst can result in a decrease in the utilization of the catalyst. Systems using pumps increase the complexity and volume of the system. Finally, CO is produced along with carbon atoms and oxygen atoms. In the system using platinum catalyst, CO temporarily poisons the platinum catalyst, although the electrode can be added with a ruthenium atom to react the CO on the poisoned catalyst and get rid of the catalyst. However, when the CO concentration is too high, the fuel cell has to increase the electrode. The bismuth content, which is also the electrode active area of ​​the DMFC is 10 times that of the PEMFC.
Developed a DMFC system for motorcycles. Figure 4 shows the structure of this system and the name of each part of its device. The principle of power generation and the structure of the battery theme can also be seen in Figure 5. This system claims to have a rated output of 500W, a rated voltage of 24V and a weight of 20kg. In this system, a fuel tank and a water tank are stored, and a 50% methanol solution is stored in the fuel tank. The function of the water tank is to maintain the concentration of the methanol-water solution supplied to the battery main body at a constant 1 M/L (3.2% mass). ). In the battery body, the aqueous solution contains CO2 bubbles generated by chemical reactions, which are transported back to the tank through the pipeline loop, and the bubbles are isolated. Yamaha has developed a special concentration sensor and control circuit for monitoring the concentration of methanol. The working principle of this system is such that when the concentration of methanol in the solution passed to the battery body is low to some extent, the system will produce a The control signal is used to transfer a high concentration of methanol solution from a methanol tank to the solution to be reacted to increase their concentration. In addition, Yamaha has developed a high-efficiency air pump to pump air to the cathode of the battery body, which contains a screening program. Finally, the air passes through the vapor device through the heat exchanger member where it is used to accelerate the concentration of the solution and finally they are transported out of the system. In a low concentration solution tank, the moisture content of the used solution is controlled and excess water is released outside the system. In order to integrate this system into the motorcycle, the structure of the battery should be adjusted according to the shape of the motorcycle to achieve a balance of weight.
Developed DMFC for military use. Shows the fuel cell shown at the Fuel Cell Show in November 2006, showing the "MOBION 1M" portable fuel cell developed by MTI for military use, using 100% methanol as fuel, rated at 0.7 W, the external dimensions are 34mm × 95mm × 153mm. The fuel cartridge is built-in and has an energy density of 150 Wh per fill. Through MIT's mobion technology, 100% methanol can be directly injected into the anode of the DMFC, thus avoiding the problems of other types of DMFCs requiring water to be injected into the battery body, and eliminating the need to add micro pumps and micro-systems to the system. The subsystem of the catheter. Its principle can be referred to in the MTI technology by controlling to maintain a constant supply of 100% methanol, and evenly distributing them through the battery body without using a pump.
Second, RMFC
RMFC is actually a PEMFC that recombines methanol, and only methanol is used as the main raw material. The difference is that an external recombiner is used, usually a tiny methanol recombiner. In the RMFC, methanol does not directly enter the battery body for chemical reaction, thus avoiding the defects of the DMFC described above, and it can also make up for the insufficient output power of the DMFC. According to the research results of casio and hitachi last year, the output energy density of methanol fuel cells can be increased to 200mW/cm2, or higher, which means that its output power can exceed 10W to drive portable devices.
1. Introduction In order to maintain the energy density of PEMFC, avoid the power attenuation caused by external reorganization; in addition, due to the need of a certain temperature environment during the reorganization process, increasing the temperature of recombination will help to increase the hydrogen-oxygen conversion rate of methanol. Therefore, the proper control of temperature and chemical dose can give the desired concentration of hydrogen and oxygen. At present, steam recombination or autothermal recombination temperature can be as low as 200-300 °C. Another benefit of using external recombination is that the recombined gas can qualitatively oxidize CO, thereby reducing CO problems and reducing the amount of catalyst used, but high-temperature fuel cells resistant to CO poisoning can also be used.
Since the operating temperature of the micro-recombined methanol fuel cell is as high as 200-300 ° C, and the current problems faced by the RMFC are the start-up time and the start-up temperature, the micro RMFC usually burns the catalyst on the upper layer of the recombiner to quickly reach the start-up. The starting temperature of the reorganization. Both DMFC and RMFC need to add micro-rechargeable batteries to cope with sudden power requirements, and hybrid fuel cells and secondary batteries can also be used to reduce the power requirements of fuel cells.
2. The RMFC prototype developed by Casio is a prototype of a recombined methanol fuel cell exhibited by Casio in November 2006. In the demonstration, this system can drive digital cameras. The prototype compactly assembles a Reformer, a Cell Stack, and two Fuel Cartridges, and the fuel line is mounted at the bottom. Other components include two liquid pumps for supplying methanol to the battery body, a liquid flow sensor for measuring the flow of methanol, an on/off valve for controlling the supply of methanol, and a pump for air and hydrogen. Different valves control the flow of air, and two flow sensors for measuring air act as auxiliary devices. As can be seen in the prototype, the control circuits are not integrated, the DC/DC circuits and control circuits are peripheral circuits, which are not shown in Figure 8.
(1) The structure of the Casio prototype. This system uses methanol at a concentration of 60% mass as a fuel. Methanol was delivered to the recombiner from two 8 mL fuel cartridges (18 mm diameter, 10 mm length) by two liquid pumps while the flow was controlled by a liquid sensor. The liquid pump was jointly developed by Casio and Fraunhofer IZM (a research institute in Germany). The reformer produces hydrogen from methanol by steam reforming. The resulting hydrogen is either transferred to the fuel cell body or combusted in a reformer to ensure the temperature required for the catalyst at startup. For this reason, on/off valves are used to control flow on different flow channels.
In addition to supplying air to the fuel cell body, the air pump must inject air into the recombinator to remove the incidental CO. In addition, the supply of air is also for the combustion of hydrogen to promote the reaction rate of the catalyst in the reformer. Air is injected directly into the fuel cell body by the pump without the need for a valve. Air flow sensors and different types of valves are installed in each channel of the recombinator to accurately control air flow. The power generated by the fuel cell is then supplied to a digital camera via a DC/DC converter circuit to drive a digital camera. When the four batteries used in the fuel cell main body drive the digital camera in the way of the demonstration, Casio claims that 20 batteries can drive the notebook. In order to commercialize in 2008, the company plans to release fuel cell samples after upgrading the prototype.
(2) Several important components of the Casio prototype. The prototype includes an electronic penetration (EO) pump that was introduced on November 29 last year. This device accurately dispenses methanol fuel while maintaining a high voltage in a compressed 0.5 cc unit. It is manufactured from materials manufactured by NANO Fu-sion Technologies. Casio's successful experience in the RMFC field also includes other key components such as thermal insulation recombiners for extracting hydrogen from methanol, as well as fuel cell bodies, etc., see Figure 9. The so-called "EO pump" mentioned here is a small fuel pump composed of an electroosmotic material which is a dielectric similar to helium and which generates an electric potential when it comes into contact with a liquid. When the voltage is applied to it, the liquid inside it will flow. Regardless of the size, it distributes liquid at high pressure and does not use a motor drive. More importantly, it operates without noise and eliminates problems such as vibration. Casio developed this liquid fuel pump with its patented technology combined with Nano Fusion's electro-permeable material (1mm diameter, 1mm thick), which is mainly used in RMFC in mobile devices. Casio has solved the inherent problems in EO pumps, such as changes in the magnetic susceptibility of electroosmotic materials due to collisions, such as the accumulation of vapor bubbles generated during liquid electrolysis. Finally, the EO pump can be concentrated in a 0.5 cc container and maintain a flow rate of 90 μL/min even at a pressure of 100 kPa.
Another important device recombiner uses the principle of water vapor to heat methanol to 280 ° C and extract hydrogen therefrom. Its structure is shown in Figure 10. In fact, this reorganizer has undergone several improvements, and it is said that it currently solves the problems of insulation, long startup time and excessive CO generation, and casio claims to ship recombiner samples for laptops in 2007. In terms of internal structure, the main components of the recombiner are two glass substrates, and they are vacuum insulated, and a thin film of gold is coated on the inner surface of the substrate to minimize heat radiation. According to reports, the surface temperature of this recombiner is 40 ° C, or 20 ° C higher than room temperature. The recombiner consists of three channels, one for the hydrogen combustion channel to provide heat for the methanol to recombine hydrogen, the recombination reaction channel for the fuel and water vapor reactions to be carried out, and the CO channel for elimination to eliminate the CO by-product.
3, Ultracell25
As early as 2005, Ultracell introduced an RMFC and claimed that its energy density is twice that of a normal lithium-ion battery. At about 40 ounces, the size of the battery is comparable to that of a flat paper novel. Through the technology of ultracell, the used waste fuel can be "hot swap" and reused to ensure continuous power supply. The RMFC was originally developed for military use by ultracell, model XX90, which provides 45 watts of power. The commercial use of ultracell25 was released in 2006 and can be used in the corporate, industrial and mobile devices sectors, with a corresponding military version of XX25. Figure 11 shows the RMFC product XX25 for military use from Ultracell, which is said to power 72 hours of uninterrupted production equipment.
Third, several fuel cell comparisons Several other fuel cells include melt-cast carbonate FC (MCFC), solid oxide FC (SOFC), phosphoric acid FC (PAFC), which are also used for electricity and heat generation. MCFCs typically use natural gas as a fuel. SOFC uses hydrogen carbon compounds or H2 as fuel. MCFC and SOFC operate at high temperatures (>650°C and 800-1000°C, respectively), SOFC provides the highest power efficiency (44%-50%) and can exceed 80% in co-generation mode. In addition, a polymer electrolyte film FC (PEMFC) is also often used in electric vehicles, and can also be used for fixed electric power generation. In order not to emit harmful substances, PEMFC requires a pure H2 input and does not produce CO2 during the reaction. They operate at low temperatures to provide 35%-40% conversion efficiency. Most fuel cell vehicles use PEMFC, and it also accounts for 70%-80% of the small solid fuel cell market. In the medium and long term, MCFC and SOFC are expected to occupy the large-size solid fuel cell market. SOFC currently accounts for 15%-20% of this market segment. Thousands of FCs are produced globally each year, 80% of which are used for stationary and mobile equipment, and the rest for fuel cell vehicle demonstration projects.
If the cost of H2 and fuel cells is greatly reduced, and the rules for limiting CO2 emissions are introduced and effectively implemented, then FC may achieve significant market growth in the next 10 years (to 30% market share by 2050). The potential for fixed FC distribution growth depends on the raw material price list rules, which depend on the price of electronic materials and natural gas. SOFC and MCFC use natural gas as the main fuel, and by 2050, it will occupy 5% of the global fuel cell market share.
So far, no actual methanol fuel cell products have entered the civilian market. The development of methanol fuel cells is still underway. The research direction is mostly focused on the miniaturization of batteries, service life, energy density, and power efficiency. Improvements, it takes time for the methanol fuel cell to actually be mass-produced. In any case, most people think that methanol fuel cells will replace traditional batteries as the main power source for portable devices. It can be seen that in recent years, various manufacturers have successively launched their own prototypes/prototypes. This article roughly describes the principle of DMFC, and introduces RMFC from the defects of DMFC. Finally, several prototypes and products of RMFC are listed.
First, DMFC
In terms of technical principles, the DMFC is mature. It can generate stable energy immediately, and does not need to cool the battery body during the reaction; the methanol fuel used is easy to store because it is in liquid form, and does not condense in cold environments; it is safe in size and weight reduction. The DMFC is also easy to do. All these advantages make the DMFC more advantageous than other types of fuel cells in some applications. For example, we can see the DMFC in the household appliances such as lawnmowers and chainsaws, and we can also see the passenger liner. The store uses DMFC as a backup energy source, and the micro DMFC becomes an alternative energy source for portable devices. Figure 1 shows the DMFC-based music player from Toshiba.
The DMFC typically includes a permeable electrolyte membrane through which methanol passes through the anode of the DMFC and air passes through the cathode of the DMFC. The chemical reaction with methanol and air produces electricity, which does not burn and only produces CO2 and water. Methanol is decomposed into hydrogen atoms and CO2, and protons form H2O with O2 in the air, and electrons pass through an external circuit to reach the negative electrode of the film. The equation for the chemical reaction is as follows:
Full reaction equation:
CH3OH +3/2O2=CO2 + 2H2O
anode:
CH3OH + H2O=CO2 + 6H+ + 6e-
cathode:
3/2O2 + 6H+ + 6e-=3H2O
2. Defects of DMFC Electrolyte membranes of methanol aqueous fuel cells (DMFC) mostly use Perfluoro sulfone acid-based materials. Since this material forms a cluster inside, protons surrounded by water molecules can form a channel for proton hydrates. Therefore, the conductivity of the proton is very high, however, the same combination of methanol as the proton hydrate crosses the film and reduces the utilization of methanol. This is known as the crossover phenomenon of methanol. Once the methanol penetrates, it will be at the cathode. The catalyst reacts with oxygen, which causes problems such as voltage drop. Increasing the battery capacity is very effective using a high concentration aqueous methanol solution, but a high concentration aqueous methanol solution is also liable to cause methanol breakthrough. Therefore, the electrolyte membrane is required to have high proton conductivity, and it is also necessary to control the penetration of methanol. This is actually a fatal flaw in the DMFC. Hydrogen ions need to be carried by water through the polymer film. In order to avoid this situation, researchers have taken various other methods to prevent the penetration of methanol, such as increasing the isolation of methanol and high. The isolation layer of the molecular film, the use of a water-repellent gradient, and the like.
Another problem faced by the DMFC is the discharge of CO2. Although methanol can be supplied passively (ie, without the use of a pump), the accumulation of CO2 in the catalyst can result in a decrease in the utilization of the catalyst. Systems using pumps increase the complexity and volume of the system. Finally, CO is produced along with carbon atoms and oxygen atoms. In the system using platinum catalyst, CO temporarily poisons the platinum catalyst, although the electrode can be added with a ruthenium atom to react the CO on the poisoned catalyst and get rid of the catalyst. However, when the CO concentration is too high, the fuel cell has to increase the electrode. The bismuth content, which is also the electrode active area of ​​the DMFC is 10 times that of the PEMFC.
Developed a DMFC system for motorcycles. Figure 4 shows the structure of this system and the name of each part of its device. The principle of power generation and the structure of the battery theme can also be seen in Figure 5. This system claims to have a rated output of 500W, a rated voltage of 24V and a weight of 20kg. In this system, a fuel tank and a water tank are stored, and a 50% methanol solution is stored in the fuel tank. The function of the water tank is to maintain the concentration of the methanol-water solution supplied to the battery main body at a constant 1 M/L (3.2% mass). ). In the battery body, the aqueous solution contains CO2 bubbles generated by chemical reactions, which are transported back to the tank through the pipeline loop, and the bubbles are isolated. Yamaha has developed a special concentration sensor and control circuit for monitoring the concentration of methanol. The working principle of this system is such that when the concentration of methanol in the solution passed to the battery body is low to some extent, the system will produce a The control signal is used to transfer a high concentration of methanol solution from a methanol tank to the solution to be reacted to increase their concentration. In addition, Yamaha has developed a high-efficiency air pump to pump air to the cathode of the battery body, which contains a screening program. Finally, the air passes through the vapor device through the heat exchanger member where it is used to accelerate the concentration of the solution and finally they are transported out of the system. In a low concentration solution tank, the moisture content of the used solution is controlled and excess water is released outside the system. In order to integrate this system into the motorcycle, the structure of the battery should be adjusted according to the shape of the motorcycle to achieve a balance of weight.
Developed DMFC for military use. Shows the fuel cell shown at the Fuel Cell Show in November 2006, showing the "MOBION 1M" portable fuel cell developed by MTI for military use, using 100% methanol as fuel, rated at 0.7 W, the external dimensions are 34mm × 95mm × 153mm. The fuel cartridge is built-in and has an energy density of 150 Wh per fill. Through MIT's mobion technology, 100% methanol can be directly injected into the anode of the DMFC, thus avoiding the problems of other types of DMFCs requiring water to be injected into the battery body, and eliminating the need to add micro pumps and micro-systems to the system. The subsystem of the catheter. Its principle can be referred to in the MTI technology by controlling to maintain a constant supply of 100% methanol, and evenly distributing them through the battery body without using a pump.
Second, RMFC
RMFC is actually a PEMFC that recombines methanol, and only methanol is used as the main raw material. The difference is that an external recombiner is used, usually a tiny methanol recombiner. In the RMFC, methanol does not directly enter the battery body for chemical reaction, thus avoiding the defects of the DMFC described above, and it can also make up for the insufficient output power of the DMFC. According to the research results of casio and hitachi last year, the output energy density of methanol fuel cells can be increased to 200mW/cm2, or higher, which means that its output power can exceed 10W to drive portable devices.
1. Introduction In order to maintain the energy density of PEMFC, avoid the power attenuation caused by external reorganization; in addition, due to the need of a certain temperature environment during the reorganization process, increasing the temperature of recombination will help to increase the hydrogen-oxygen conversion rate of methanol. Therefore, the proper control of temperature and chemical dose can give the desired concentration of hydrogen and oxygen. At present, steam recombination or autothermal recombination temperature can be as low as 200-300 °C. Another benefit of using external recombination is that the recombined gas can qualitatively oxidize CO, thereby reducing CO problems and reducing the amount of catalyst used, but high-temperature fuel cells resistant to CO poisoning can also be used.
Since the operating temperature of the micro-recombined methanol fuel cell is as high as 200-300 ° C, and the current problems faced by the RMFC are the start-up time and the start-up temperature, the micro RMFC usually burns the catalyst on the upper layer of the recombiner to quickly reach the start-up. The starting temperature of the reorganization. Both DMFC and RMFC need to add micro-rechargeable batteries to cope with sudden power requirements, and hybrid fuel cells and secondary batteries can also be used to reduce the power requirements of fuel cells.
2. The RMFC prototype developed by Casio is a prototype of a recombined methanol fuel cell exhibited by Casio in November 2006. In the demonstration, this system can drive digital cameras. The prototype compactly assembles a Reformer, a Cell Stack, and two Fuel Cartridges, and the fuel line is mounted at the bottom. Other components include two liquid pumps for supplying methanol to the battery body, a liquid flow sensor for measuring the flow of methanol, an on/off valve for controlling the supply of methanol, and a pump for air and hydrogen. Different valves control the flow of air, and two flow sensors for measuring air act as auxiliary devices. As can be seen in the prototype, the control circuits are not integrated, the DC/DC circuits and control circuits are peripheral circuits, which are not shown in Figure 8.
(1) The structure of the Casio prototype. This system uses methanol at a concentration of 60% mass as a fuel. Methanol was delivered to the recombiner from two 8 mL fuel cartridges (18 mm diameter, 10 mm length) by two liquid pumps while the flow was controlled by a liquid sensor. The liquid pump was jointly developed by Casio and Fraunhofer IZM (a research institute in Germany). The reformer produces hydrogen from methanol by steam reforming. The resulting hydrogen is either transferred to the fuel cell body or combusted in a reformer to ensure the temperature required for the catalyst at startup. For this reason, on/off valves are used to control flow on different flow channels.
In addition to supplying air to the fuel cell body, the air pump must inject air into the recombinator to remove the incidental CO. In addition, the supply of air is also for the combustion of hydrogen to promote the reaction rate of the catalyst in the reformer. Air is injected directly into the fuel cell body by the pump without the need for a valve. Air flow sensors and different types of valves are installed in each channel of the recombinator to accurately control air flow. The power generated by the fuel cell is then supplied to a digital camera via a DC/DC converter circuit to drive a digital camera. When the four batteries used in the fuel cell main body drive the digital camera in the way of the demonstration, Casio claims that 20 batteries can drive the notebook. In order to commercialize in 2008, the company plans to release fuel cell samples after upgrading the prototype.
(2) Several important components of the Casio prototype. The prototype includes an electronic penetration (EO) pump that was introduced on November 29 last year. This device accurately dispenses methanol fuel while maintaining a high voltage in a compressed 0.5 cc unit. It is manufactured from materials manufactured by NANO Fu-sion Technologies. Casio's successful experience in the RMFC field also includes other key components such as thermal insulation recombiners for extracting hydrogen from methanol, as well as fuel cell bodies, etc., see Figure 9. The so-called "EO pump" mentioned here is a small fuel pump composed of an electroosmotic material which is a dielectric similar to helium and which generates an electric potential when it comes into contact with a liquid. When the voltage is applied to it, the liquid inside it will flow. Regardless of the size, it distributes liquid at high pressure and does not use a motor drive. More importantly, it operates without noise and eliminates problems such as vibration. Casio developed this liquid fuel pump with its patented technology combined with Nano Fusion's electro-permeable material (1mm diameter, 1mm thick), which is mainly used in RMFC in mobile devices. Casio has solved the inherent problems in EO pumps, such as changes in the magnetic susceptibility of electroosmotic materials due to collisions, such as the accumulation of vapor bubbles generated during liquid electrolysis. Finally, the EO pump can be concentrated in a 0.5 cc container and maintain a flow rate of 90 μL/min even at a pressure of 100 kPa.
Another important device recombiner uses the principle of water vapor to heat methanol to 280 ° C and extract hydrogen therefrom. Its structure is shown in Figure 10. In fact, this reorganizer has undergone several improvements, and it is said that it currently solves the problems of insulation, long startup time and excessive CO generation, and casio claims to ship recombiner samples for laptops in 2007. In terms of internal structure, the main components of the recombiner are two glass substrates, and they are vacuum insulated, and a thin film of gold is coated on the inner surface of the substrate to minimize heat radiation. According to reports, the surface temperature of this recombiner is 40 ° C, or 20 ° C higher than room temperature. The recombiner consists of three channels, one for the hydrogen combustion channel to provide heat for the methanol to recombine hydrogen, the recombination reaction channel for the fuel and water vapor reactions to be carried out, and the CO channel for elimination to eliminate the CO by-product.
3, Ultracell25
As early as 2005, Ultracell introduced an RMFC and claimed that its energy density is twice that of a normal lithium-ion battery. At about 40 ounces, the size of the battery is comparable to that of a flat paper novel. Through the technology of ultracell, the used waste fuel can be "hot swap" and reused to ensure continuous power supply. The RMFC was originally developed for military use by ultracell, model XX90, which provides 45 watts of power. The commercial use of ultracell25 was released in 2006 and can be used in the corporate, industrial and mobile devices sectors, with a corresponding military version of XX25. Figure 11 shows the RMFC product XX25 for military use from Ultracell, which is said to power 72 hours of uninterrupted production equipment.
Third, several fuel cell comparisons Several other fuel cells include melt-cast carbonate FC (MCFC), solid oxide FC (SOFC), phosphoric acid FC (PAFC), which are also used for electricity and heat generation. MCFCs typically use natural gas as a fuel. SOFC uses hydrogen carbon compounds or H2 as fuel. MCFC and SOFC operate at high temperatures (>650°C and 800-1000°C, respectively), SOFC provides the highest power efficiency (44%-50%) and can exceed 80% in co-generation mode. In addition, a polymer electrolyte film FC (PEMFC) is also often used in electric vehicles, and can also be used for fixed electric power generation. In order not to emit harmful substances, PEMFC requires a pure H2 input and does not produce CO2 during the reaction. They operate at low temperatures to provide 35%-40% conversion efficiency. Most fuel cell vehicles use PEMFC, and it also accounts for 70%-80% of the small solid fuel cell market. In the medium and long term, MCFC and SOFC are expected to occupy the large-size solid fuel cell market. SOFC currently accounts for 15%-20% of this market segment. Thousands of FCs are produced globally each year, 80% of which are used for stationary and mobile equipment, and the rest for fuel cell vehicle demonstration projects.
If the cost of H2 and fuel cells is greatly reduced, and the rules for limiting CO2 emissions are introduced and effectively implemented, then FC may achieve significant market growth in the next 10 years (to 30% market share by 2050). The potential for fixed FC distribution growth depends on the raw material price list rules, which depend on the price of electronic materials and natural gas. SOFC and MCFC use natural gas as the main fuel, and by 2050, it will occupy 5% of the global fuel cell market share.
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