Bipolar Plate Flow Layout for Even Coolant Distribution
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Solution Overview
Problem
In fuel cell stacks, the channel structure of bipolar plates leads to uneven mass flow distribution of coolant and fuel due to differences in boundary conditions at inlet and outlet regions, resulting in some surfaces not being supplied with coolant, particularly in embossed metallic plates where multiple channels are connected through a distribution channel, causing inefficiencies in cooling and fuel delivery.
Innovation Solution
The bipolar plate design features a distribution channel structure where the cooling fluid flows at an angle to the main flow direction, with a greater thickness in the distribution region than in the active field, allowing for optimized installation space and even mass flow distribution. This design includes embossed regions forming channel structures, with the cooling fluid channel structure and fuel channel structure aligned to ensure homogeneous flow, and the distribution channel structure is angled to compensate for the thickness difference, ensuring all surfaces are supplied with coolant and fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a distribution channel is used to connect multiple channels in the active field, then the pressure drop of reactants is reduced, but unequal mass flow distribution is created in the active field for the cooling fluid
Solution Approach 1:
The distribution channel is designed with a three-dimensional structure that includes a first region and a second region at different heights. The cooling fluid inlet is positioned in the first region while outlets are in the second region, utilizing vertical dimensionality to redistribute cooling fluid evenly across all active fields despite the horizontal pressure gradient caused by the distribution channel
Solution Approach 2:
The distribution channel is segmented into multiple regions (first region and second region) at different heights, with separate inlet and outlet positions. This segmentation allows independent control of cooling fluid entry and exit points, enabling even distribution to multiple active fields while maintaining the pressure-reducing distribution function
2Volume of moving object
If the thickness of the bipolar plate is increased in the distribution region, then installation space is optimized, but the overall plate complexity increases
Solution Approach 1:
The bipolar plate thickness is increased locally only in the distribution region where additional space is needed for the three-dimensional channel structure, while maintaining standard thickness in the active field regions. This localized thickening provides the necessary installation space for even cooling fluid distribution without unnecessarily increasing overall plate complexity
Data Source
AI summary
The invention relates to a bipolar plate (10) for a fuel cell stack (100). The bipolar plate (10) has a main extension plane (HE) and a main flow direction (HR) on the main extension plane (HE), a first bipolar plate half (12), a second bipolar plate half (14), an active field (40). a distribution region (50), and a port region (60).The port region (60) lias at least one port for supplying al least one fluid (F) onto the main extension plane (HE),said active field (40) having at least one cooling fluid channel structure (42) for a cooling process using a cooling fluid (KF) and al least one fuel channel structure (44) for supplying at least one fluid (F) to at least one adjacent membrane electrode assembly (110) of the fuel cell stack (100). The first bipolar plate lialf (12) and the second bipolar plate half (14) form at least one distribution channel structure (52) in the distribution region (50). wherein the distribution channel structure (52) is designed such that a cooling fluid (KF) flows through the distribution channel structure at an angle to the main flow direction (HR) on the main extension plane (HE), and the thickness (D1) of the bipolar plate (10) in the distribution region (50) is greater than the greatest thickness (D2) of the bipolar plate (10) in the active field (40).The invention additionally relates Io a fuel cell stack (100) with at least one bipolar plate (10) and at least one membrane electrode assembly (110).