Bipolar Plate Cooling Structure for Fuel Cell Corner Heat

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Solution Overview

Problem

Bipolar plates in electrochemical cells, such as fuel cells, experience inhomogeneous temperature fields due to isotropic flow resistance, leading to inefficient cooling and potential material durability issues from temperature peaks.

Innovation Solution

The bipolar plate design features offset elevations on plate elements, creating direction-dependent flow resistance and pass areas, allowing cooling water to preferentially flow into corner areas, thereby enhancing cooling efficiency and uniformity of the temperature field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If elevations on plate elements are arranged in a centered symmetric pattern, then manufacturing is simplified, but temperature distribution becomes inhomogeneous with local peaks

Engineering Contradiction:
Improveease of manufactureVSAvoidtemperature uniformity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent applies asymmetry by offsetting the elevations of the first plate element relative to the second plate element, creating an asymmetric arrangement that directs cooling water flow into corner areas. This asymmetric configuration eliminates temperature peaks and achieves homogeneous temperature distribution, resolving the contradiction between manufacturing simplicity and temperature uniformity.

Inventive Principle:
Principle #4Asymmetry

2Temperature

If cooling water flow is directed primarily along the length of the cell, then central areas are well cooled, but corner areas experience reduced flow and higher temperatures

Engineering Contradiction:
Improvecooling efficiencyVSAvoidflow distribution
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent applies local quality by creating direction-dependent flow resistance through the offset elevation arrangement. This causes the cooling water flow to adapt locally to different areas of the bipolar plate, with increased flow into corner areas and appropriate flow along the length, achieving homogeneous cooling throughout all regions.

Inventive Principle:
Principle #3Local quality

3Device complexity

If isotropic flow resistance is used, then flow paths are simple, but temperature peaks occur in corner areas due to reduced flow

Engineering Contradiction:
Improveflow channel complexityVSAvoidtemperature peaks
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent replaces isotropic (uniform in all directions) flow resistance with anisotropic (direction-dependent) flow resistance by offsetting the elevations. This asymmetric arrangement creates direction-dependent flow paths that naturally direct cooling water into corner areas, eliminating temperature peaks without requiring complex flow channel geometries.

Inventive Principle:
Principle #4Asymmetry

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 design ensures improved cooling distribution, reducing temperature peaks and enhancing the durability of materials by directing cooling water effectively into corner areas, resulting in a more uniform temperature field.

Implementation Method 1

the flow resistance being isotropic evenly over the surface... the flow resistance inhomogeneous or direction-dependent

Methodology Applied
Scientific EffectFlow resistance: Pressure Drop

Implementation Method 2

cooling water flows through them during operation... removing the reaction heat... improved cooling distribution

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP4078704B1Cooling of a fuel cell
Publication Date: 2023.11.08 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP4078704B1 patent drawingFigure 1~2
  • EP4078704B1 patent drawingFigure 3~4
  • EP4078704B1 patent drawingFigure 5~6

AI summary

The invention relates to a bipolar plate (1) for an electrochemical cell, comprising a flow space (4) which is arranged between a first plate element (2) and a second plate element (3) and has a flow inlet (5) and a flow outlet (6) for a coolant (K) flowing through the flow space (4), wherein each plate element (2, 3) has a contact plane (7) for contacting the other plate element (2, 3) in question and, between the flow inlet (5) and the flow outlet (6), a plurality of elevations (8) which protrude from the contact plane (7) and face away from the other plate element (2, 3) in question, which elevations have openings (9) facing the contact plane (7), and wherein first flow channels (10) are formed through the openings (9) in the elevations (8) by the elevations (8) of the two plate elements (2, 3) being offset from one another, wherein each elevation (8) at least partially overlaps at least one elevation (8) of the other plate element (2, 3) in question, wherein a direction-dependent flow resistance is set in the first flow channels (10) of the bipolar plate (1). The invention also relates to an electrochemical cell comprising a bipolar plate (1) according to the invention.