Solid Polymer Electrolyte Membrane With Laser-Machined Ceramic Support

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Solution Overview

Problem

Solid polymer electrolyte membranes, such as those made of perfluorosulfonic acid (PFSA), suffer from low mechanical strength, leading to tearing and electrical shorting, especially when wet, and existing composite membranes with microporous structures have reduced conductivity and inadequate strength due to tortuous pore pathways and uniform pore distribution.

Innovation Solution

A novel solid polymer electrolyte composite membrane is created using a ceramic support with laser-machined pores arranged in a defined pattern, filled with a solid polymer electrolyte, providing enhanced mechanical strength and conductivity while maintaining dimensional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If PFSA PEM is made thin to decrease membrane resistance, then conductivity is improved, but mechanical strength deteriorates leading to tearing and shorting

Engineering Contradiction:

Improvemembrane resistanceVSAvoidmechanical strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent combines PFSA polymer with a microporous PTFE support layer to create a composite membrane structure. The PTFE support provides mechanical strength and dimensional stability, allowing the membrane to be made thinner without sacrificing structural integrity. This composite approach enables reduced membrane resistance while preventing tearing and electrical shorting that would occur in thin homogeneous PFSA membranes.

Inventive Principle:

Principle #40Composite materials

2Strength

If PFSA PEM is cross-linked to improve mechanical strength, then strength is improved, but brittleness increases under dry conditions

Engineering Contradiction:

Improvemechanical strengthVSAvoidbrittleness under dry conditions

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The microporous PTFE support layer serves as a mechanical reinforcement that provides strength without requiring cross-linking of the PFSA polymer. This avoids the brittleness issue associated with cross-linked membranes under dry conditions, as the PTFE support maintains flexibility and structural integrity across varying humidity conditions.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If homogeneous PFSA polymer is used, then manufacturing is simplified, but mechanical strength and durability deteriorate

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidmechanical strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent uses a microporous PTFE support layer with a homogeneous PFSA polymer coating. The PTFE support can be manufactured using established processes like electrochemical oxidation of metal sheets or sintering, providing a structurally sound base that simplifies the overall manufacturing approach while dramatically improving mechanical strength compared to homogeneous thin PFSA membranes.

Inventive Principle:

Principle #40Composite materials

4Strength

If microporous structure is introduced to improve strength, then mechanical strength is improved, but conductivity decreases due to tortuous pore pathways

Engineering Contradiction:

Improvemechanical strengthVSAvoidconductivity

Core Design Contradiction:

StrengthVSUse of energy by moving object

Solution Approach 1:

The patent creates a hierarchical pore structure where the microporous PTFE support provides mechanical strength, while the PFSA polymer fills the pores and provides ionic conduction pathways. The PFSA coating continuity ensures low resistance by providing direct conduction paths, while the PTFE support's porosity maintains mechanical integrity without creating tortuous pathways that would hinder conductivity.

Inventive Principle:

Principle #3Local quality

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 membrane exhibits improved mechanical strength and conductivity, reducing the risk of tearing and shorting, and allows for direct catalyst coating and uniform pressure distribution, enhancing the performance and durability of electrochemical devices.

Implementation Method 1

a plurality of pores extending from said top surface to said bottom surface; and (b) a first solid polymer electrolyte at least partially filling at least some of said pores

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

a first solid polymer electrolyte at least partially filling at least some of said pores

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS7947405B2Solid polymer electrolyte composite membrane comprising porous ceramic support

Publication Date: 2011.05.24 PLUG POWER

AI summary

A solid polymer electrolyte composite membrane and method of manufacturing the same. The composite membrane comprises a porous ceramic support having a top surface and a bottom surface. The porous ceramic support may be formed by laser micromachining a ceramic sheet or may be formed by electrochemically oxidizing a sheet of the base metal. A solid polymer electrolyte fills the pores of the ceramic support and preferably also covers the top and bottom surfaces of the support. Application of the solid polymer electrolyte to the porous support may take place by applying a dispersion to the support followed by a drying off of the solvent, by hot extrusion of the solid polymer electrolyte (or by hot extrusion of a precursor of the solid polymer electrolyte followed by in-situ conversion of the precursor to the solid polymer electrolyte) or by in-situ polymerization of a corresponding monomer of the solid polymer electrolyte.