Fuel Cell Stack Load Measurement Mechanism
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Solution Overview
Problem
Existing fuel cell stacks face challenges in maintaining uniform pressure distribution across unit cells due to variations in tightening loads over time, leading to reduced performance and the need for frequent re-tightening processes.
Innovation Solution
A fuel cell stack design incorporating a load measurement mechanism with load sensors and a pressure mechanism that applies a tightening load via load cells, allowing for accurate detection and adjustment of the load distribution across the stacked body, ensuring uniform pressure and enhanced tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tie-rod bolts are used to tighten the fuel cell stack, then the stacking structure is simple and easy to manufacture, but the pressure distribution becomes non-uniform and tightening load decreases over time
Solution Approach 1:
The single tie-rod bolt tightening system is segmented into multiple independent pressing blocks, each equipped with its own load cell and pressure control device. This segmentation allows independent control of pressure at different locations, enabling uniform pressure distribution across the fuel cell stack while maintaining structural simplicity.
Solution Approach 2:
Load cells are introduced as intermediary elements between the pressing blocks and the fuel cell stack. These load cells measure the actual pressure applied at each location and provide feedback to the pressure control devices, enabling precise control of pressure distribution without complicating the overall stacking structure.
2Manufacturing precision
If pressure force control devices are used to apply uniform pressure, then pressure distribution is improved, but the device complexity and re-tightening process complexity increase
Solution Approach 1:
The pressure control system is designed with universal components where each pressing block with its load cell and pressure control device can serve multiple functions: initial tightening, uniform pressure application, and re-tightening. This multi-functionality reduces overall system complexity by using identical modular units for different operational phases.
Solution Approach 2:
Load cells provide real-time feedback on the pressure applied at each location, which is then used by the pressure control devices to automatically adjust and maintain uniform pressure distribution. This closed-loop feedback system simplifies the control process and reduces the need for complex manual adjustment mechanisms.
3Reliability
If re-tightening is performed using tie-rod bolts, then tightening load compensation is achieved, but pressure distribution uniformity is lost
Solution Approach 1:
During the initial assembly, the pressing blocks are positioned and calibrated to apply uniform pressure across all fuel cell units. This preliminary uniform pressure application ensures that when re-tightening is needed later, the same modular pressing blocks can be reused to restore uniform pressure distribution, maintaining both reliability and precision.
Solution Approach 2:
The pressure control system is designed to be dynamic and adaptable, allowing the pressure control devices to adjust the force applied by each pressing block based on real-time load cell measurements. This dynamic adjustment capability enables the system to maintain uniform pressure distribution during both initial tightening and re-tightening operations.
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 enables precise detection and uniform distribution of tightening loads, improving power generation performance and simplifying the re-tightening process by maintaining optimal load conditions over time.
Implementation Method 1
A load measurement mechanism including a plurality of load sensors integrally connected to a connector member is provided between one of the end plates and the stacked body
Implementation Method 2
The pressure mechanism presses the load measurement mechanism toward the stacked body to thereby apply a tightening load to the stacked body via the plurality of load sensors
Data Source
AI summary
A fuel cell stack including a plurality of fuel cells each formed by stacking separators and an electrolyte membrane-electrode assembly. The electrolyte membrane-electrode assembly includes an electrolyte membrane provided with a pair of electrodes on the opposite sides thereof. A stacked body formed by stacking the fuel cells is provided with a pair of end plates at the opposite ends thereof in a stacking direction. The end plates are integrally fixed by fastening members with the distance between the end plates maintained. A load measurement mechanism including a plurality of load sensors integrally connected to a connector member is provided between one of the end plates and the stacked body. The one of the end plates is provided with a pressure mechanism. The pressure mechanism presses the load measurement mechanism toward the stacked body to thereby apply a tightening load to the stacked body via the load sensors.