Bipolar Plate Bypass Channel Layout for Uniform Reactant Flow

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Solution Overview

Problem

Existing bipolar plates in fuel cells suffer from reactant bypass, leading to reduced utilization and concentration gradients that impair the electrochemical reaction efficiency.

Innovation Solution

The design incorporates bypass channels outside the active reaction area with flow connections and blockers to redirect reactants to areas of lower concentration, ensuring uniform distribution and increased reactant concentration at the edges of the flow field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a bypass channel is provided to allow reactant flow around the flow field, then reactant distribution can be improved, but reactant bypass and loss increase

Engineering Contradiction:
Improvereactant distributionVSAvoidreactant bypass loss
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The bypass channel is positioned specifically outside the active area rather than through it, creating different flow paths with different functions. The flow connection is located at a specific location (half of the flow field facing the outlet port) where reactant concentration is already reduced, optimizing the local reactant distribution without causing overall bypass loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The flow connection acts as an intermediary element that mediates between the bypass channel and the flow field. It controls the transfer of reactant from the bypass channel into the flow field at a strategically chosen location, allowing regulated mixing of fresh and consumed reactant to optimize distribution while preventing direct bypass.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If reactant is introduced into areas with already reduced concentration, then concentration gradients are reduced, but reaction efficiency may be compromised

Engineering Contradiction:
Improvereactant concentration uniformityVSAvoidelectrochemical reaction efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The invention changes the spatial parameter of reactant introduction by locating the flow connection in the half of the flow field facing the outlet port, where reactant concentration is already reduced. This parameter change optimizes the concentration gradient distribution, improving uniformity while maintaining sufficient driving force for the electrochemical reaction.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4022701B1Bipolar plate
Publication Date: 2026.03.11 AUDI AG
  • EP4022701B1 patent drawingFigure 1~2
  • EP4022701B1 patent drawingFigure 3~4
  • EP4022701B1 patent drawingFigure 5~7

AI summary

The invention relates to a bipolar plate (10) with a first inlet port (13) and a flow field (12) having a plurality of channels (11) for connecting the first inlet port (13) to a first outlet port (14) for a first reactant, and with a second inlet port (15) and a flow field (12) having a plurality of channels (11) for connecting the second inlet port (15) to a second outlet port (16) for a second reactant, at least one bypass channel (25) being present at the edge of at least one of the flow fields (12). Associated with the bypass channel (25) is at least one flow connection (26), which branches out of the bypass channel (25) into an adjacent edge channel (27) of the flow field (12).