GB/T 20042.7-2024 PDF EnglishUS$665.00 · In stock · Download in 9 seconds
GB/T 20042.7-2024: Proton exchange membrane fuel cells - Part 7: Test method of carbon paper properties Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB/T 20042.7: Historical versions
Similar standardsGB/T 20042.7-2024: Proton exchange membrane fuel cells - Part 7: Test method of carbon paper properties---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT20042.7-2024 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 27.070 CCS K 82 Replacing GB/T 20042.7-2014 Proton exchange membrane fuel cell - Part 7.Test method of carbon paper properties Issued on. DECEMBER 31, 2024 Implemented on. JULY 01, 2025 Issued by. Status Administration for Market Regulation; National Standardization Administration. Table of ContentsForeword... 3 Introduction... 5 1 Scope... 6 2 Normative references... 6 3 Terms and definitions... 6 4 Symbols... 9 5 Sample and test preparation... 12 6 Test instruments and apparatus... 13 7 Thickness uniformity test... 14 8 Resistance test... 15 9 Mechanical strength test... 19 10 Gas permeability test... 21 11 Porosity test... 23 12 Bulk density test... 23 13 Surface density test... 24 14 Roughness test... 24 15 Through-plane thermal conductivity test... 26 16 Bending stiffness test... 28 17 Static contact angle test... 28 18 Durability test (acid oxidation method)... 28 19 Test Report... 28 Appendix A (Informative) Test Preparation... 30 Appendix B (Informative) Test report... 31 Appendix C (Informative) Test of the total resistance of the two copper electrodes and the contact area specific resistance between the carbon paper and the electrodes... 33 Appendix D (Informative) Test for in-plane gas permeability... 34 Appendix E (Informative) Porosity test... 36 Appendix F (Informative) Surface roughness test method... 38 Appendix G (Informative) Bending stiffness test... 40 Appendix H (Informative) Static contact angle test... 42 Appendix I (Informative) Durability test (acid oxidation method)... 43 References... 451 ScopeThis document defines the terms and definitions of carbon paper for proton exchange membrane fuel cells; describes the test methods for the properties of carbon paper for proton exchange membrane fuel cells, including thickness uniformity test, resistance test, mechanical strength test, air permeability test, porosity test, bulk density test, surface density test, roughness test, vertical thermal conductivity test, bending stiffness test, static contact angle test, durability test, as well as the test report. This document is applicable to the detection of carbon paper for proton exchange membrane fuel cells.2 Normative referencesThe contents of the following documents constitute the essential terms of this document through normative references in the text. Among them, for dated references, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies to this document. GB/T 1040.3-2006 Plastics - Determination of tensile properties - Part 3.Test conditions for films and sheets GB/T 20042.1-2017 Proton exchange membrane fuel cell - Part 1.Terminology GB/T 28816-2020 Fuel cell - Terminology3 Terms and definitionsThe terms and definitions defined in GB/T 20042.1-2017 and GB/T 28816-2020, as well as the following terms and definitions, apply to this document. 3.1 Area specific resistance Under specified pressure conditions, the ohmic resistance of carbon paper multiplied by its effective area. Note. The unit of area specific resistance is milliohm square centimeter (mΩ·cm2). 3.2 Through-plane resistivity The resistivity in the direction perpendicular to the surface of carbon paper. Note. The unit of through-plane resistivity is milliohm centimeters (mΩ·cm). 3.3 In-plane resistivity The resistivity in the direction parallel to the surface of carbon paper. Note. The unit of in-plane resistivity is milliohm centimeters (mΩ·cm). 3.4 Through-plane gas permeability The permeability in the direction perpendicular to the surface of carbon paper. Note. The unit of through-plane gas permeability is milliliter millimeters per square centimeter hour Pa [mL·mm/(cm2·h·Pa)]. 3.5 In-plane gas permeability The permeability in the direction parallel to the surface of carbon paper. Note. The unit of in-plane gas permeability is milliliter millimeters per square centimeter hour Pa [mL·mm/(cm2·h·Pa)]. 3.6 Porosity The percentage of pore volume of carbon paper to its total volume.4 SymbolsThe following symbols apply to this document. Note. The symbols, meanings, units used in this document are shown in Table 1, including appropriate units of measurement.5 Sample and test preparation5.1 Sample preparation 5.1.1 The shape, size, quantity of the sample to be tested shall be determined by negotiation between the tester and the sample sender. 5.2 Test preparation 5.2.1 For each test, testing instruments and equipment that meet the accuracy requirements shall be selected, to minimize the measurement error. 5.2.3 Each test shall be tested at least 3 times (to ensure that 3 valid values are obtained). 5.2.4 Unless otherwise specified, the temperature of the test environment is 23 °C ± 5 °C.6 Test instruments and apparatusThe instruments and apparatus used in the test methods given in this document and their accuracy requirements are as follows.7 Thickness uniformity test7.1 Test method 7.1.1 The zero point of the thickness gauge shall be calibrated before each measurement; the zero point shall be rechecked after each set of specimen measurements. 7.2 Data processing 7.2.1 The thickness uniformity of the sample is expressed by the average thickness, thickness standard deviation, thickness dispersion coefficient. 7.2.2 The average thickness is calculated according to formula (1). 7.2.3 Thickness standard deviation is calculated according to formula (2). 7.2.4 Thickness dispersion coefficient is calculated according to formula (3).8 Resistance test8.1 In-plane resistivity test 8.1.1 Test method 8.1.1.1 Use a length measuring instrument to measure the length and width of the sample. 8.1.2 Data processing Calculate the in-plane resistivity according to formula (4). 8.2 Through-plane resistivity test 8.2.1 Test method 8.2.2 Data processing Calculate the through resistivity according to formula (5). 8.3 Area specific resistance test 8.3.1 Test method9 Mechanical strength test9.1 Tensile strength test 9.1.1 Test method 9.1.1.1 Measure the average thickness of the sample according to the method in Chapter 7. 9.1.1.4 Perform a tensile strength test on a mechanical properties testing machine. The tensile rate shall be maintained at 10 mm/min. 9.1.1.5 After the specimen breaks, read the corresponding load value. If the specimen breaks somewhere within ±5 mm of the marking line, the result shall be discarded. 9.1.2 Data processing 9.2 Compression property test 9.2.1 Cut the test material with the same cross-sectional size as the flat plate fixture of the testing machine, as the sample. 9.2.2 Place the sample between two smooth flat plate fixtures. During the test, pressure is applied to the outside of the two clamps; a clamp displacement value and the sample thickness dpi are recorded for each 0.05 MPa increase in pressure. When the specified pressure is reached, the test is stopped. 9.2.3 Calculate the compression rate of the sample according to formula (8). ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. 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