Fuel Cell Dummy Cell Liquid Management
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Solution Overview
Problem
In fuel cell modules, liquid formation in the reactant gas supply path can lead to blockages, reducing electricity generation efficiency due to water condensation or flow from upstream devices, especially under acceleration or low temperatures.
Innovation Solution
Incorporating a dummy cell with a lower pressure loss reactant gas flow path than the fuel cells, along with design features like spacers and gas diffusion layers, to direct liquid away from the fuel cells, ensuring that the reactant gas flow rate into the dummy cell is higher than into the fuel cells, thus minimizing liquid inflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dummy cell is added to the fuel cell module, then liquid inflow into fuel cells is suppressed, but device complexity increases
Solution Approach 1:
A dummy cell is introduced as an intermediary component between the reactant gas supply path and the fuel cells. This dummy cell acts as a mediator that absorbs excess liquid through its higher gas permeability, preventing liquid from entering the fuel cells while maintaining system functionality.
Solution Approach 2:
The dummy cell utilizes porous materials with high gas permeability to allow reactant gas to pass through while capturing liquid. The porous structure enables selective permeation where gas can flow freely but liquid is retained, solving the liquid inflow problem without blocking the gas supply path.
2Reliability
If reactant gas flow rate into dummy cell is increased, then liquid inflow into fuel cells is reduced, but pressure loss in fuel cell system increases
Solution Approach 1:
Different regions of the system are given different flow resistance characteristics. The dummy cell is designed with locally optimized high permeability properties compared to the fuel cells, creating a localized low-resistance path that naturally directs gas flow distribution without requiring system-wide pressure increases.
Solution Approach 2:
The gas permeability parameter of the dummy cell is specifically adjusted to be higher than that of the fuel cells. By changing this physical parameter, the system achieves automatic flow distribution where the dummy cell absorbs excess gas flow and associated liquid, while the fuel cells receive appropriate flow rates without excessive pressure loss.
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 configuration effectively suppresses liquid inflow into the fuel cells, maintaining proper electricity generation by ensuring the reactant gas flow path of the dummy cell has a lower pressure loss than that of the fuel cells, preventing blockages and maintaining efficiency.
Implementation Method 1
Pressure loss of the reactant gas flow path of the dummy cell is smaller than pressure loss of the reactant gas flow path of the fuel cells
Implementation Method 2
When a liquid is present in the reactant gas supply path, the liquid will be carried downstream by the reactant gas
Implementation Method 3
a spacer that has aeration properties and that is interposed between the first separator and the second separator
Implementation Method 4
a gas diffusion layer that has aeration properties
Implementation Method 5
a gas diffusion layer that has aeration properties
Data Source
AI summary
A fuel cell module includes a stack including a plurality of fuel cells stacked together, at least one dummy cell in contact with the stack at an end portion of the stack in a stacking direction, a reactant gas supply path configured to supply a reactant gas that is either a fuel gas or an oxidant gas to the fuel cells and the dummy cell, and a reactant gas discharge path in communication with the fuel cells and the dummy cell. The fuel cells and the dummy cell each include a reactant gas flow path configured to cause the reactant gas from the reactant gas supply path to flow toward the reactant gas discharge path. Pressure loss of the reactant gas flow path of the dummy cell is smaller than pressure loss of the reactant gas flow path of the fuel cells.