Fuel Cell Current Collector with Variable Resistance Plates
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Solution Overview
Problem
Fuel cells experience slow cold start times and reduced durability of the membrane electrode assembly due to temperature distribution issues and open circuit voltage fluctuations, particularly during cold start and low power operations.
Innovation Solution
A current collector system with multiple plates of varying resistance values is integrated into the end plate, allowing for a self-discharge mode during cold starts and low power operations, where a high-resistance plate is used to rapidly heat the fuel cell and a low-resistance plate is used during normal operations, with a selection switch and controller to manage the modes based on temperature and voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a current collector plate with minimum resistance is used, then electricity supply efficiency is maximized, but cold start ability deteriorates due to insufficient heat generation
Solution Approach 1:
The system dynamically switches between different current collector plates based on operating conditions. A selection switch connects either the first current collector plate (high resistance) or the second current collector plate (minimum resistance) to the load, enabling adaptive resistance adjustment. During cold start, the high-resistance plate generates heat through I²R losses; during normal operation, the minimum-resistance plate maximizes power output.
Solution Approach 2:
The electrical resistance parameter of the current collector is changed based on operating conditions. The first current collector plate has higher resistance for heat generation during cold start, while the second current collector plate has minimum resistance for efficient power delivery during normal operation. The controller adjusts the resistance parameter by switching between plates according to temperature and power demand.
2Device complexity
If a single current collector plate is used, then device complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The current collector is segmented into multiple independent plates with different resistance characteristics. The first current collector plate and second current collector plate are separately constructed with distinct electrical properties, allowing each segment to serve specific functional requirements under different operating conditions.
Solution Approach 2:
The current collector system achieves multi-functionality by incorporating both high-resistance and minimum-resistance plates. The same current collector assembly can provide both heat generation (during cold start) and efficient power delivery (during normal operation), making the system universally adaptable to various operational requirements.
3Loss of energy
If minimum resistance current collector plate is used during cold start, then power loss is reduced, but temperature increase is insufficient for rapid startup
Solution Approach 1:
The system converts what would normally be wasted energy (I²R heat losses) into a beneficial effect during cold start. By intentionally using a high-resistance current collector plate, the electrical energy that would be lost as heat is instead utilized to warm up the fuel cell stack, transforming an energy loss into a useful heating function that enables rapid cold start.
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 solution improves cold startability by rapidly increasing the fuel cell temperature and reduces durability issues by consuming open circuit voltage, ensuring stable power generation and extended membrane electrode assembly life.
Implementation Method 1
a current collector plate formed of a material having a large resistance is selected, in a case where it is necessary to generate heat from a fuel cell during cold start
Implementation Method 2
a membrane electrode assembly (MEA) is positioned in the center of each unit cell of the fuel cell stack. The MEA preferably comprises a solid polymer electrolyte membrane 10, through which hydrogen ions (protons) are transported, and catalyst layers including a cathode (air electrode) 12 and an anode (fuel electrode) 14, which are suitably coated on both sides of the electrolyte membrane 10 so that hydrogen reacts with oxygen
Data Source
AI summary
The present invention provides a current collector of an end plate for a fuel cell and a method for controlling the same, in which a plurality of current collector plates having different resistance values is mounted on an end plate so that the current of a fuel cell is consumed during cold start and during low power operation to improve cold startability of the fuel cell and, further, the durability of a membrane electrode assembly (MEA) is improved due to an increase in voltage during low power operation.