Fuel Cell Bipolar Plate with Variable Channel Widths

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Solution Overview

Problem

Existing fuel cell bipolar plates do not optimize power density and efficiency due to fixed channel and web structures, which lead to suboptimal fluid, heat, and charge transport, and are costly to produce with rigid materials.

Innovation Solution

The fuel cell bipolar plate features varying channel widths, web widths, and channel spacings along the flow direction to adapt to local conditions, allowing for optimized fluid, heat, and charge transport, and can be made from flexible, cost-effective materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If fixed channel and web structures are used in bipolar plates, then manufacturing is simplified, but power density and efficiency are not optimized due to suboptimal fluid, heat, and charge transport

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpower density
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies local quality by varying the channel width and web width along the flow direction to match local transport requirements. The channel width increases and web width decreases in the flow direction, optimizing fluid distribution, heat removal, and charge transport at different locations within the bipolar plate, thereby resolving the contradiction between manufacturing simplicity and power density optimization.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by transitioning from fixed, uniform channel and web structures to variable-width structures that adapt along the flow direction. This dynamic geometric variation allows the bipolar plate to optimize transport properties at different locations, improving power density while maintaining manufacturability through continuous or stepped width variations.

Inventive Principle:
Principle #15Dynamics

2Productivity

If variable channel and web widths are implemented, then fluid, heat, and charge transport are optimized, but manufacturing complexity increases

Engineering Contradiction:
Improvetransport efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent resolves this contradiction by implementing local quality through controlled geometric variations. The channel and web widths are varied systematically along the flow direction rather than randomly, creating an optimized transport structure that can be manufactured using techniques like variable depth embossing or multi-layer assembly, thus balancing transport efficiency with manageable manufacturing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the bipolar plate into multiple zones with different channel and web width characteristics. This segmentation allows optimization of transport properties in different regions while enabling modular manufacturing approaches, where each zone can be formed or assembled separately, thereby reducing overall manufacturing complexity despite the variable geometry.

Inventive Principle:
Principle #1Segmentation

3Strength

If rigid materials are used for bipolar plates, then structural strength is ensured, but production costs increase

Engineering Contradiction:
Improvestructural strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies this principle by utilizing flexible, thin-film materials for the bipolar plate structure. These flexible materials can be formed into the required variable channel and web width geometries through processes like embossing or lamination, reducing material costs compared to rigid materials while maintaining sufficient structural strength through the optimized geometric design and support from adjacent components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs composite materials by combining flexible bipolar plate materials with supportive structures or coatings. This composite approach allows the use of cost-effective flexible base materials while incorporating localized reinforcement or functional coatings to ensure adequate structural strength, thereby resolving the contradiction between material cost and structural requirements.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2297808B1Bipolar plate for a fuel cell arrangement, in particular for placement between two adjacent membrane electrode arrangements
Publication Date: 2014.02.26 MERCEDES BENZ GROUP AG
  • EP2297808B1 patent drawingFigure 1
  • EP2297808B1 patent drawingFigure 2~4
  • EP2297808B1 patent drawingFigure 5

AI summary

The invention relates to a bipolar plate (3) for a fuel cell arrangement (1), in particular for placement between two adjacent membrane electrode arrangements, comprising at least one or two plates disposed plane-parallel relative to one another, wherein a flow field (F) is formed from the channel structures made in the respective plate at least on one or both outsides, respectively, said channel structures comprising a plurality of channels (K) running between a fluid inlet (E) and a fluid outlet (A) and a plurality of webs (S) running between two channels (K). According to the invention, the channels (K) and/or the webs (S) comprise at least one varying channel width (b1), one varying web width (b2) and/or one varying channel distance (a) on at least one of the outsides along a flow direction (R) of a fluid between the fluid inlet (E) and the fluid outlet (A).