Fuel Cell Bipolar Plate ALD Coating for Corrosion and Water Management

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Solution Overview

Problem

Fuel cell bipolar plates face challenges with corrosion resistance and water management, particularly due to the harsh environment and reactive gases, leading to energy loss and low power stability, which conventional noble metal coatings fail to address effectively.

Innovation Solution

A process involving anodizing a conductive metal plate to form a corrosion-resistant surface layer with a water contact angle less than 40 degrees, followed by depositing a conductive layer using atomic layer deposition (ALD) with materials like metal oxides, nitrides, or carbon to enhance corrosion resistance and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional noble metal coatings (gold, platinum) are applied to bipolar plates, then corrosion resistance is improved, but water contact angle increases above 40 degrees leading to poor water management

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidwater management

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention changes the surface properties of the bipolar plate by applying a hydrophilic coating that reduces the water contact angle to below 40 degrees, fundamentally altering the wetting characteristics to improve water management while maintaining corrosion resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite coating structure combining hydrophilic materials with corrosion-resistant properties, creating a multi-functional surface layer that simultaneously addresses both corrosion protection and water management requirements

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If low cost metal sheets (stainless steel, aluminum) are used for bipolar plates, then manufacturing cost and weight are reduced, but corrosion resistance deteriorates due to fluoride ions from membrane electrolyte

Engineering Contradiction:

Improvemanufacturing costVSAvoidcorrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention introduces a protective coating layer as an intermediary between the metal substrate and the corrosive fuel cell environment, blocking fluoride ions from attacking the metal while allowing the plate to maintain its low cost and light weight advantages

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces expensive noble metal bipolar plates with affordable metal sheets that have limited corrosion resistance, but compensates by applying a protective coating that extends their service life and reliability

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If metal plates are made into very thin sheets for low weight and cost, then productivity and ease of manufacture are improved, but corrosion resistance deteriorates due to increased surface area to volume ratio

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidcorrosion resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention employs a thin protective coating film on the metal bipolar plate that provides corrosion resistance without significantly increasing the overall thickness, allowing the plate to remain thin and lightweight while gaining enhanced durability

Inventive Principle:

Principle #30Flexible shells and thin films

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

The solution provides bipolar plates with excellent corrosion resistance, low electric contact resistance, and improved water management, ensuring stable fuel cell performance and power density.

Implementation Method 1

anodizing the conductive metal plate to form a corrosion resistant surface layer

Methodology Applied

Scientific EffectAnodizing: Anodising

Implementation Method 2

depositing at least one conductive layer above the corrosion resistant surface layer using atomic layer deposition method

Methodology Applied

Scientific EffectAtomic layer deposition: Physical Vapour Deposition

Data Source

PatentUS9136545B2Low cost fuel cell bipolar plate and process of making the same

Publication Date: 2015.09.15 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Fuel cell bipolar plates are made by depositing a pinhole free corrosion resistant and/or a conductive layer on a metal plate using an atomic layer deposition method. In one embodiment, a conductive layer is deposited on an anodized metal plate using atomic layer deposition method. In another embodiment, at least one corrosion resistant metal oxide layer and at least one conductive layer are deposited on a metal plate individually using atomic layer deposition method. In yet another embodiment, a corrosion resistant and conductive metal oxynitride layer is deposited on a metal plate using an atomic layer deposition method.