GB/T 20042.6-2024 Proton exchange membrane fuel cell - Part 6: Test method of bipolar plate properties
1 Scope
This document specifies the test methods for the flexural strength, density, electrical resistance, corrosion current density, etc. of bipolar plate materials for proton exchange membrane fuel cells, as well as the test methods for the area utilization, thickness uniformity, groove depth uniformity, flatness, relative flatness, interfacial contact resistance, gas tightness, etc. of bipolar plate components.
This document is applicable to bipolar plate materials and components for various types of proton exchange membrane fuel cells.
Note: The bipolar plate materials and bipolar plate components are defined as follows:
a) Bipolar plate materials: Sheet materials in the same state as the finished bipolar plate materials;
b) Bipolar plate components: Finished bipolar plates in the same state as their intended use.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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 230.2 Metallic materials - Rockwell hardness test - Part 2: Verification and calibration of testing machines and indenters
GB/T 1958 Geometrical product specifications (GPS) - Geometrical tolerance - Verification
GB/T 4472-2011 Determination of density and relative density for chemical products
GB/T 13465.2 Test method of impermeable graphite materials - Part 2: Flexure strength
GB/T 19466.4-2016 Plastics - Differential scanning calorimetry (DSC) - Part 4: Determination of specific heat capacity
GB/T 20042.1-2017 Proton exchange membrane fuel cell - Part 1: Terminology
GB/T 20428-2006 Granite surface plates
GB/T 22588-2008 Determination of thermal diffusivity or thermal conductivity by the flash method
GB/T 28634 Microbeam analysis - Electron probe microanalysis - Quantitative point analysis for bulk specimen using wavelength dispersive X-ray spectroscopy
GB/T 30693-2014 Measurement of water-contact angle of plastic films
GB/T 30707-2014 Testing method on adhesion of fine ceramic coatings - Scratching
GB/T 30902 Inorganic chemicals for industrial use - Determination of impurity element - Inductively coupled plasma optical emission spectrometry (ICP-OES)
GB/T 31563-2015 Metallic coatings - Measurement of coating thickness - Scanning electron microscope method
GB/T 34672 Chemical reagent - General rules for the ion chromatography
JJG 508 Resistivity measuring instruments with four-probe array method
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
corrosion current density
current value generated per unit area on the surface of a bipolar plate material or component due to electrochemical damage at the corrosion potential in a simulated fuel cell operating environment
Note 1: The magnitude of the corrosion current density reflects the corrosion rate of the bipolar plate and is a physical quantity characterizing the corrosion resistance of bipolar plate materials and components in a simulated fuel cell operating environment.
Note 2: The corrosion current density is expressed in μA/cm2.
3.2
interfacial contact resistance
electrical resistance generated due to contact between the test areas of two materials
Note 1: The interfacial contact resistance of a bipolar plate primarily refers to the contact resistance between the effective area of the bipolar plate corresponding to the membrane electrode assembly and the carbon paper.
Note 2: The interfacial contact resistance is expressed in mΩ·cm2.
3.3
through-plane resistivity
resistivity value of a bipolar plate material in the direction perpendicular to the plate surface
Note: The through-plane resistivity is expressed in mΩ·cm.
3.4
in-plane resistivity
resistivity value of a bipolar plate material in the direction parallel to the plate surface
Note: The in-plane resistivity is expressed in mΩ·cm.
3.5
flexural strength
maximum bending stress that a bipolar plate can withstand during bending under specified conditions
Note: The flexural strength is expressed in MPa.
3.6
flatness
sum of the distances from the highest peak point and the lowest valley point on the extracted surface of the measured portion of a bipolar plate to the fitted plane under specified pressure
Note 1: The flatness of a bipolar plate directly affects the interfacial contact resistance between the bipolar plate and the gas diffusion layer, thereby influencing cell performance.
Note 2: The flatness is expressed in mm.
3.7
relative flatness
maximum bending amount of a bipolar plate in its free state expressed as a percentage of the plate length
Note: The relative flatness of a bipolar plate directly affects the dimensional assembly accuracy of the bipolar plate in the cell, thereby influencing cell performance.
4 Flexural strength test for bipolar plate materials
4.1 Test instruments
The test instruments shall include the following equipment and tools:
——Testing machine: With an accuracy meeting the requirements of class 0.5;
——Test fixture: It shall not cause damage to the sample; during application of the load, the longitudinal axis of the sample shall coincide with the tensile direction passing through the centerline of the fixture;
——Test indenter: With a radius of 5.0mm±0.1mm;
——Thickness gauge: With an accuracy of 1μm, used to measure the thickness of the sample;
——Vernier caliper: With an accuracy of 0.02mm, used to measure the length and width of the sample.
4.2 Sample preparation
Contents
Foreword II
Introduction IV
1 Scope
2 Normative references
3 Terms and definitions
4 Flexural strength test for bipolar plate materials
5 Density test for bipolar plate materials
6 Resistance test for bipolar plate materials
7 Corrosion current density test for bipolar plate materials
8 Area utilization test for bipolar plate components
9 Thickness uniformity test for bipolar plate components
10 Groove depth uniformity test for bipolar plate components
11 Flatness test for bipolar plate components
12 Relative flatness test for bipolar plate components
13 Interfacial contact resistance test for bipolar plate components
14 Gas tightness test for bipolar plate components
15 Water contact angle test for bipolar plate components
16 Coating thickness test for bipolar plate components
17 Coating adhesion strength test for bipolar plate components
18 Corrosion current density test for bipolar plate components
19 Specific heat capacity test for bipolar plate components
20 Thermal conductivity test for bipolar plate components
21 Test for composition and concentration of precipitated ions from bipolar plate components
22 Test index applicability, test preparation and test report
Annex A (Normative) Test index applicability
Annex B (Informative) Test preparation
Annex C (Informative) Test report
Bibliography
