Proton Exchange Membrane Fuel Cell — Part 3: Test Method for Proton Exchange Membrane
1 Scope
This document describes the thickness uniformity test, proton conductivity test, equivalent weight test, gas permeation rate test, tensile property test, swelling rate test and water absorption test of for proton exchange membrane used in proton exchange membrane fuel cells.
This document is applicable to all types of proton exchange membranes.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1040.3-2006 Plastics — Determination of Tensile Properties — Part 3: Test Conditions for Films and Sheets (ISO 527-3:1995, IDT)
GB/T 1446-2005 Fiber-reinforced Plastics Composites — The Generals for Determination of Properties
GB/T 20042.1-2017 Proton Exchange Membrane Fuel Cell — Part 1: Terminology
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 20042.1-2017 and the following apply.
3.1
proton conductivity
ability of the membrane to conduct protons; proton conductivity is the inverse of the resistivity.
Note 1: Proton conductivity is an electrochemical index to measure the proton conductivity of the membrane, which reflects the mobility of protons within the membrane.
Note 2: Proton conductivity is expressed in Siemens per centimeter (S/cm).
3.2
equivalent weight; EW
mass of a dry membrane containing 1 mole of protons
Note 1: It has a reciprocal relationship with IEC (Ion Exchange Capacity), which indicates the size of the ion exchange capacity, reflecting the acid concentration in the proton exchange membrane.
Note 2: Equivalent weight is expressed in grams per mole (g/mol).
3.3
tensile strength
ratio of the maximum tensile force before fracture to the cross-sectional area of a standard membrane sample applied to the tensile force at a given temperature, humidity and tensile speed
Note 1: Transverse tensile strength: the tensile strength of the membrane parallel to the reel direction of membrane, expressed as σTD.
Note 2: Longitudinal tensile strength: the tensile strength of the membrane perpendicular to the reel direction of membrane, expressed as σMD.
3.4
modulus of elasticity in tension
slope of initial straight part of the stress-strain curve of proton exchange membrane
Note 1: Transverse modulus of elasticity in tension: the tensile modulus of the membrane parallel to the reel direction of membrane, expressed as ETD.
Note 2: Longitudinal modulus of elasticity in tension: the tensile elastic modulus of the membrane perpendicular to the reel direction of membrane, expressed as EMD.
Note 3: The slopes of the two points on the recommended stress-strain curve with strains ε1 = 0.5% and ε2 = 2.5% are the elastic modulus.
Note 4: The modulus of elasticity in tension is expressed as E and in Megapascals (MPa).
3.5
tensile strain at break
increment per unit length of the original gauge length at the time of sample fracture
Note 1: Transverse tensile strain at break: the fracture tensile strain of the membrane parallel to the reel direction of membrane, expressed as εTD.
Note 2: Longitudinal tensile strain at break: the fracture tensile strain of the membrane perpendicular to the reel direction of membrane, expressed as εMD.
Note 3: Tensile strain at break is expressed as ε, in dimensionless ratio or percentage (%).
3.6
peeling force at 180° angle
load required for the continuous peeling, at 180° angle, of sample with a certain width and tested at a certain speed
Note: Peeling force at 180° angle, is expressed in newtons per millimeter (N/mm).
3.7
gas permeation rate
volume of gas passing through the sample per unit area per unit time at constant temperature and unit pressure difference
Note: gas permeation rate is expressed as volume value at standard temperature and pressure, in cubic centimeters per square meter per day per Pascal [cm3/(m2·d·Pa)].
3.8
gas permeation coefficient
volume of gas permeating through the sample per unit thickness and per unit area per unit time at stable transmission and at constant temperature and unit pressure difference.
Note: Gas permeation coefficient is expressed as volume value at standard temperature and pressure, in cubic centimeters by centimeter per square centimeter per second per Pascal [cm3·cm/(cm2·s·Pa)].
3.9
water uptake
water absorption of dry membrane per unit mass at a given temperature
Note: Water absorption is expressed as %.
3.10
swelling rate
size change relative to the dry membrane in transverse, longitudinal and thickness directions at a given temperature
Note 1: Dimensional changes in the transverse, longitudinal and thickness directions are denoted as TD, MD and Z axes respectively.
Note 2: Swelling rate is expressed as %.
Foreword III
Introduction V
1 Scope
2 Normative References
3 Terms and Definitions
4 Thickness Uniformity Test
4.1 Test apparatus
4.2 Sample preparation and conditioning
4.3 Test methods
4.4 Data processing
5 Proton Conductivity Test
5.1 Test apparatus
5.2 Sample preparation and conditioning
5.3 Test methods
5.4 Data processing
6 Equivalent Weight (EW) Test
6.1 Instruments and apparatus
6.2 Preparation of samples
6.3 Test methods
6.4 Data processing
7 Gas Permeation Rate Test
7.1 Test apparatus
7.2 Preparation of sample
7.3 Test methods
7.4 Data processing
8 Tensile Performance Test
8.1 Instruments and apparatus
8.2 Sample preparation and conditioning
8.3 Test methods
8.4 Calculation and expression of results
9 Peeling Force at 180° Angle
9.1 Test apparatus
9.2 Sample preparation and conditioning
9.3 Test methods
9.4 Expression of results
10 Swelling Rate Test
10.1 Test apparatus
10.2 Sample preparation and conditioning
10.3 Test methods
10.4 Data processing
11 Water Uptake Test
11.1 General
11.2 Test apparatus
11.3 Sample preparation
11.4 Test methods
11.5 Data processing
Annex A (Informative) Preparation
A.1 General
A.2 Data acquisition and recording
Annex B (Informative) Test Report
B.1 General
B.2 Report contents
B.3 Report type
