Development of bipolar plates as key components for air breathing PEM fuel cell and stack assembly method

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F18%3A43916125" target="_blank" >RIV/60461373:22310/18:43916125 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60461373:22310/18:43916138

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Development of bipolar plates as key components for air breathing PEM fuel cell and stack assembly method

Popis výsledku v původním jazyce

Fuel cells with polymer electrolyte (PEM FCs) represent a promising device for efficient conversion of chemical energy carried by fuel (hydrogen) into electrical energy. They possess several important advantages, such as high efficiency, high flexibility, silent operation, nontoxic reaction products (pure water) or absence of moving parts. The main application of this type of fuel cell in nowadays foreseen in car propulsion or in other mobile applications. Old generation of electric car used motors with operation voltage of 48 to 76 V. It was a reason, why maximal speed of these cars was 90 km per hour. Modern electric cars operate typically with voltage in a range of 300 to 400 V. Hydrogen fuel cell can provide maximal voltage of 1.223 V. It is clearly insufficient for desired applications. Using of voltage convertor to increase this value is possible. Nevertheless, such a high difference between original and target voltage decrease efficiency of conversion and increases complexity of converter. Fuel cells are therefore arranged into stacks to increase resulting operation voltage and to simplify the voltage conversion. Bipolar plates represent one of the vital components in such fuel cell stack. Bipolar plates have to be made of material with high chemical resistance, high electronic conductivity, high mechanical strength and low permeability. Chemical resistance is necessary, because corrosion of the cell would poison the cell. Low permeability of the material is necessary due the safety reasons (prevents mixing of hydrogen and oxygen). High electronic conductivity is essential to maintain the ohmic losses low. High mechanical strength of the material is necessary to minimize amount of material needed and thus to reduce the weight of stack. Both sides of bipolar plate are provided by gas distribution channels. They ensure homogeneous distribution of fuel and oxidation across the electrodes surface. Construction of bipolar electrode have to allow sealing and insulation of individual electrodes in stack. Bipolar plates are currently produced mainly from the carbon-based materials or from metals. Carbon based materials used in the fuel cells industry can be divided into two groups. First group represent high density microcrystalline graphite with density in range 1.9 – 2.1 g cm-3. Second group represents composite material based on carbon black particles blended with suitable polymer. Second group has a lower density, lower permeability for gases, better machinability and mechanical properties. Negative aspect represents higher ohmic resistance of this composite in comparison with high densities graphite. Finally, the membranes used to produce the fuel cells in a stack typically allow high current densities at low ohmic loses. This is typically achieved by choosing membranes of low thickness. One of disadvantages of thin membranes is low mechanical stability and tendency for rolling. Both problems is possible to solve by using fixation frame. T has to respect during its design properties of the electrodes to be used to assembly the MEA.

Název v anglickém jazyce

Development of bipolar plates as key components for air breathing PEM fuel cell and stack assembly method

Popis výsledku anglicky

Fuel cells with polymer electrolyte (PEM FCs) represent a promising device for efficient conversion of chemical energy carried by fuel (hydrogen) into electrical energy. They possess several important advantages, such as high efficiency, high flexibility, silent operation, nontoxic reaction products (pure water) or absence of moving parts. The main application of this type of fuel cell in nowadays foreseen in car propulsion or in other mobile applications. Old generation of electric car used motors with operation voltage of 48 to 76 V. It was a reason, why maximal speed of these cars was 90 km per hour. Modern electric cars operate typically with voltage in a range of 300 to 400 V. Hydrogen fuel cell can provide maximal voltage of 1.223 V. It is clearly insufficient for desired applications. Using of voltage convertor to increase this value is possible. Nevertheless, such a high difference between original and target voltage decrease efficiency of conversion and increases complexity of converter. Fuel cells are therefore arranged into stacks to increase resulting operation voltage and to simplify the voltage conversion. Bipolar plates represent one of the vital components in such fuel cell stack. Bipolar plates have to be made of material with high chemical resistance, high electronic conductivity, high mechanical strength and low permeability. Chemical resistance is necessary, because corrosion of the cell would poison the cell. Low permeability of the material is necessary due the safety reasons (prevents mixing of hydrogen and oxygen). High electronic conductivity is essential to maintain the ohmic losses low. High mechanical strength of the material is necessary to minimize amount of material needed and thus to reduce the weight of stack. Both sides of bipolar plate are provided by gas distribution channels. They ensure homogeneous distribution of fuel and oxidation across the electrodes surface. Construction of bipolar electrode have to allow sealing and insulation of individual electrodes in stack. Bipolar plates are currently produced mainly from the carbon-based materials or from metals. Carbon based materials used in the fuel cells industry can be divided into two groups. First group represent high density microcrystalline graphite with density in range 1.9 – 2.1 g cm-3. Second group represents composite material based on carbon black particles blended with suitable polymer. Second group has a lower density, lower permeability for gases, better machinability and mechanical properties. Negative aspect represents higher ohmic resistance of this composite in comparison with high densities graphite. Finally, the membranes used to produce the fuel cells in a stack typically allow high current densities at low ohmic loses. This is typically achieved by choosing membranes of low thickness. One of disadvantages of thin membranes is low mechanical stability and tendency for rolling. Both problems is possible to solve by using fixation frame. T has to respect during its design properties of the electrodes to be used to assembly the MEA.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10405 - Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)

Projekt

<a href="/cs/project/VI20152019018" target="_blank" >VI20152019018: Vývoj a realizace nezávislého DC zdroje napájení s vodíkovým palivovým článkem</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů