Fuel Cell Bipolar Plate Coolant Flow Restrictors
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Solution Overview
Problem
Existing fuel cell bipolar plates have uniform coolant flow rates throughout the stack, which is inefficient as end portions generate less heat and do not require high coolant flow rates, leading to excessive cooling in these regions.
Innovation Solution
Incorporating stamped coolant flow restrictors in the header portions of bipolar plates, allowing for tailored coolant flow rates by using common stamping tooling and removing additional restrictors from sheets intended for higher temperature regions during trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single set of stamping tools is used for forming metal sheets in bipolar plates, then device complexity is reduced and manufacturing is simplified, but coolant flow rate cannot be tailored to match heat generation in different regions of the stack
Solution Approach 1:
The patent applies local quality by positioning flow restrictors at specific locations within the coolant channels - particularly in header portions and regions where coolant flow needs to be reduced. This allows different parts of the same bipolar plate to have different flow characteristics, enabling tailored coolant distribution without requiring different stamping tools for different plate positions in the stack.
2Ease of manufacture
If uniform coolant flow rates are used throughout the stack, then manufacturing is simplified, but excessive cooling occurs in end portions that generate less heat, reducing system efficiency
Solution Approach 1:
The patent changes the flow parameters by introducing flow restrictors that modify the coolant flow rate in specific regions. The restrictors create variable flow resistance along the coolant path, reducing flow rates in end portions and header regions where heat generation is lower, while maintaining adequate flow in high-heat-generation regions. This optimizes cooling efficiency without complicating the manufacturing process.
3Loss of energy
If additional flow restrictors are added to bipolar plates for optimized coolant distribution, then cooling efficiency improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies preliminary action by incorporating flow restrictors into the stamping process itself. The restrictors are formed as integral features of the bipolar plate during the initial stamping operation, rather than being added as separate components afterward. This preliminary incorporation of flow control features maintains manufacturing simplicity while achieving optimized coolant distribution.
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 allows for optimized coolant flow matching heat generation and loss across the fuel cell stack, reducing unnecessary cooling in lower heat generation regions and simplifying stamping tool requirements.
Implementation Method 1
Incorporating stamped coolant flow restrictors in the header portions of bipolar plates, allowing for tailored coolant flow rates
Implementation Method 2
Heat is produced in the operation of the stack of cells and coolant flow through the interior of the bipolar plates is used to cool the stack
Implementation Method 3
coolant flow through the interior of the bipolar plates is used to cool the stack
Data Source
AI summary
Bipolar plates in a fuel cell stack tend to experience lower operating temperatures near and at the ends of the stack, and these plates require lower coolant flow. But common stamping tooling can be used to make all of the plates for the stack when suitable coolant flow restrictors are stamped into each plate for lowest coolant flow. The flow restrictors are then trimmed (or their formation avoided) from those plates designated for higher coolant flow.