Direct Methanol Fuel Cell Gas Phase Fuel Supply
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Solution Overview
Problem
Direct methanol fuel cells face issues with methanol crossover, leading to reduced energy density and output due to incomplete fuel consumption and reverse electromotive force, especially when using high-concentration aqueous methanol solutions.
Innovation Solution
Supplying alcohol in a gaseous state, with minimal water content, to the fuel electrode, allowing for enhanced diffusibility and reactivity, and utilizing water generated at the air electrode to react with the alcohol at the fuel electrode, thereby reducing crossover and maintaining high energy density without external accessories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-concentration aqueous methanol solution is supplied to the fuel electrode, then energy density is improved, but methanol crossover increases leading to reduced output
Solution Approach 1:
The patent changes the physical state parameter of methanol from liquid to gas phase. By supplying methanol in gaseous form instead of aqueous solution, the system achieves both high energy density (pure methanol) and reduced crossover (gas phase diffusion control), resolving the contradiction between energy density and output
Solution Approach 2:
The patent utilizes phase transition of methanol from liquid to gas. The fuel supply unit vaporizes liquid methanol before supplying it to the fuel electrode, enabling the use of high-concentration methanol while controlling crossover through phase-controlled diffusion, thus maintaining both high energy density and output
2Ease of operation
If methanol is supplied in liquid state or as aqueous solution, then ease of supply is improved, but diffusibility and reactivity at fuel electrode deteriorate
Solution Approach 1:
The patent changes the physical state parameter of methanol from liquid to gas phase. By supplying methanol in gaseous form instead of aqueous solution, the system achieves both high energy density (pure methanol) and reduced crossover (gas phase diffusion control), resolving the contradiction between energy density and output
Solution Approach 2:
The patent utilizes phase transition of methanol from liquid to gas. The fuel supply unit vaporizes liquid methanol before supplying it to the fuel electrode, enabling the use of high-concentration methanol while controlling crossover through phase-controlled diffusion, thus maintaining both high energy density and output
3Object-affected harmful factors
If water is added to dilute methanol to reduce crossover, then crossover is reduced, but energy density deteriorates
Solution Approach 1:
The patent changes the physical state parameter of methanol from liquid to gas phase. By supplying methanol in gaseous form instead of aqueous solution, the system achieves both high energy density (pure methanol) and reduced crossover (gas phase diffusion control), resolving the contradiction between energy density and output
Solution Approach 2:
The patent utilizes phase transition of methanol from liquid to gas. The fuel supply unit vaporizes liquid methanol before supplying it to the fuel electrode, enabling the use of high-concentration methanol while controlling crossover through phase-controlled diffusion, thus maintaining both high energy density and output
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes fuel crossover, maintains high energy density, and allows for a more compact fuel cell design by utilizing water generated during the reaction, ensuring efficient and stable power generation.
Implementation Method 1
supplying alcohol in a gaseous state, with minimal water content, to the fuel electrode, allowing for enhanced diffusibility and reactivity
Implementation Method 2
a polymer solid electrolyte is used to form an ion-permeable electrolyte membrane
Implementation Method 3
methanol and water react with each other in a molar ratio of 1:1 on the fuel electrode side... Fuel electrode: CH3OH+H2O→CO2+6H++6e−... Air electrode: 3/2O2+6H++6e−→3H2O
Data Source
AI summary
An electrochemical energy generating apparatus with which the crossover of a fuel can be suppressed and a method of driving the apparatus are disclosed. The electrochemical energy generating apparatus (e.g., a fuel cell system) includes an electrochemical device (fuel cell) which has an electrolyte membrane 6 clamped between opposed electrodes and which generates electrochemical energy by a reaction of an alcohol with water at one (fuel electrode) of the electrodes and a fuel evaporating section by which a fuel including said alcohol and substantially not containing water is supplied in a gaseous state to the side of the one of the electrodes of the electrochemical device. The method of driving the electrochemical energy generating apparatus 1 includes supplying the fuel in the gaseous state to the one of the electrodes by the fuel evaporating section.