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GB/T 20042.6-2024Proton exchange membrane fuel cells - Part 6: Test methods for bipolar plate characteristics (English PDF)

质子交换膜燃料电池第6部分：双极板特性测试方法

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

March 15, 2024

Implementation date

October 1, 2024

Scope

GB/T 20042.6-2024 is the English-translated version of 质子交换膜燃料电池第6部分：双极板特性测试方法.

GB/T 20042.6-2024 specifies the test methods for the bipolar plate of a proton exchange membrane fuel cell. The bipolar plate is most of the mass and much of the cost of a stack, and it has to satisfy a set of requirements that pull against each other: conduct electricity through its thickness and across contact interfaces, conduct heat, be gas tight, resist corrosion in a hot acidic oxidising environment for thousands of hours, and be thin and cheap. The standard fixes how each of those is measured, which matters because metal and graphite composite plates are compared against each other on these numbers: the through-plane and interfacial contact resistance and the load at which it is measured, the gas permeability, the corrosion current under simulated anode and cathode conditions and the resulting ion release, the surface contact angle, the thermal conductivity, the flexural and compressive strength, the density and the dimensional and flatness measurements. The 2024 edition replaces GB/T 20042.6-2011. For a plate maker or a stack builder in China, this is the basis of comparison.

Document preview — GB/T 20042.6-2024

National Standard of the People's Republic of China

ICS: 27.070
Classification: k82
Replacing: GB/T 20042.6-2011

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

1 Scope
2 Normative References
3 Terms and Definitions
4 Flexural Strength Test of Bipolar Plate Materials
4.2 Preparation of the sample
4.3 Test methods
5 Density Test of Bipolar Plate Materials
5.2 Preparation of sample
6 Resistance Test of Bipolar Plate Material
6.2 Preparation of sample
6.3 Test methods
6.3.1 In-plane resistivity test
6.3.2 Through-plane resistivity test
6.3.3 Contact resistance test
6.4 Data processing
7 Corrosion Current Density Test of Bipolar Plate Materials
7.2 Preparation of sample
7.3 Test methods
7.3.1 Open circuit potential test
7.3.2 Dynamic potential test
7.3.3 Constant potential test
8 Area Utilization Rate Test of Bipolar Plate Component
8.2 Preparation of Sample
8.3 Test methods
9 Thickness Uniformity Test of Bipolar Plate Component
9.2 Preparation of sample
9.3 Test methods
9.4 Data processing
10 Groove Depth Uniformity Test of Bipolar Plate Component...
11 Flatness Test of Bipolar Plate Components...
12 Relative Flatness Test of Bipolar Plate Component...
13 Contact Resistance Test of Bipolar Plate Component...
14 Air Tightness Test of Bipolar Plate Component...
15 Water Contact Angle Test of Bipolar Plate Component...
16 Coating Thickness Test of Bipolar Plate Component...
17 Coating Bonding Strength Test of Bipolar Plate Component...
18 Corrosion Current Density Test of Bipolar Plate Component...
19 Specific Heat Capacity Test of Bipolar Plate Component...
20 Thermal Conductivity Test of Bipolar Plate Component...
21 Precipitation Ion Composition and Concentration Test for Bipolar Plate Component ...

1 Scope

This Document specifies the test methods for the flexural strength, density, resistance and corrosion current density, etc. of bipolar plate materials for proton exchange membrane fuel cells; and the test methods for the area utilization, thickness uniformity, groove depth uniformity, flatness, relative flatness, contact resistance, air tightness, etc. of bipolar plate components. This Document is applicable to various types of bipolar plate materials and components for proton exchange membrane fuel cells. NOTE. The definitions of bipolar plate materials and bipolar plate components are as follows:

a) Bipolar plate material. Plate material in the same state as the finished bipolar plate material;

b) Bipolar plate component. Finished bipolar plate in the same state as the used state.

2 Normative References

The provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document.

GB/T 230.2 Metallic materials - Rockwell hardness test - Part

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 The current value that is generated by the electrochemical damage caused by the corrosion potential on the surface of the bipolar plate material or component per unit area in the simulated fuel cell operating environment.

3.2 Interfacial contact resistance The resistance that is generated by the contact between the two material detection areas.

3.3 Through-plane resistivity The resistivity value of the bipolar plate material in the direction perpendicular to the plate surface. NOTE. The unit of through-plane resistivity is milliohm centimeters (mOmega·cm).

3.4 In-plane resistivity The resistivity value of the bipolar plate material in the direction parallel to the plate surface.

Note. The unit of in-plane resistivity is milliohm centimeters (mOmega·cm).

3.5 Flexural strength The maximum bending stress that a bipolar plate can withstand during bending under specified conditions.

3.6 Flatness The sum of the distances from the highest peak and the lowest valley on the surface of the measured part of the bipolar plate to the fitting plane under the specified pressure.

4 Flexural Strength Test of Bipolar Plate Materials

4.1 Test instruments The test instruments include the following equipment and tools.

4.2 Preparation of the sample

4.2.1 The width of the sample is 25mm±0.5mm and the length is 60mm±1mm. The sample size can also be determined by negotiation between the two parties. The deviation between the thickness of the sample on each part and the average thickness should not exceed 2%; and the deviation between the width and the average width shall not exceed 3%. The cross section of the sample shall be rectangular and without chamfers.

4.2.2 The number of samples is 5 (ensure 3 valid values to be obtained); and there shall be no wrinkles, scratches or damage.

4.2.3 For samples from different batches, they shall be sampled separately.

4.3 Test methods

4.3.1 Measure the width and thickness 3 times along the length of the sample; and take the average value respectively.

4.3.2 Adjust the support span to 40mm±0.3mm; place the prepared sample symmetrically on the two supports; and make the test machine pressure head and support axis perpendicular to the sample; and test the sample bending strength using the three-point bending method in accordance with GB/T 13465.2.

4.3.3 The pressure head applies load to the sample uniformly at a loading speed of 1 mm/min until the sample breaks; and the breaking load value is read.

4.4 Data processing The flexural strength of the sample is calculated according to Formula (1).

5 Density Test of Bipolar Plate Materials

5.1 Test instrument The test instrument includes the following equipment and tools.

5.2 Preparation of sample

5.2.1 The sample shape is square (5cm×5cm) and the area is 25cm2; the sample shape and size can also be negotiated by both parties to the test.

5.2.2 Clean the sample surface with ethanol or other solvents and dry it.

5.2.3 Remove grease from the metal wire.

5.3 Test methods The test is carried out according to the method specified in

4.2.3 of GB/T 4472-2011 for hydrostatic weighing method.

5.4 Data processing The density data of the sample is processed according to the method specified in

4.2.3.4 of GB/T 4472-2011.

6 Resistance Test of Bipolar Plate Material

6.1 Test instrument The test instrument includes the following equipment and tools.

6.2 Preparation of sample

6.2.1 The sample shape is square (5cm×5cm) and the area is 25cm2; the sample shape and size can also be negotiated by the test parties.

6.2.2 The number of samples is 5 (ensure 3 valid values to be obtained); and there shall be no wrinkles, scratches or damage.

6.2.3 For samples from different batches, they should be sampled separately.

6.3.1 In-plane resistivity test

6.3.1.1 The zero point of the tester shall be calibrated before each test. The influence of sample deformation, dust on the sample surface and other factors shall be avoided during the test.

6.3.2 Through-plane resistivity test

6.3.2.1 Use a low-resistance meter to test the resistance value; and the test electrode is a gold- plated copper electrode. The connection method between the gold-plated copper electrode and the wire is determined by negotiation between the two test parties to minimize the influence of the low-resistance meter on the test results.

6.3.2.2 Use a thickness gauge to measure the sample thickness; and the measurement positions shall be no less than 3.

6.3.3 Contact resistance test

6.3.3.1 Use a low resistance meter to test the resistance value; and the test electrode is a gold- plated copper electrode. The connection method between the gold-plated copper electrode and the wire is determined by negotiation between the two test parties to minimize the impact of the low resistance meter on the test results.

6.3.3.4 Use new carbon paper of the same specification for each test; and the carbon paper manufacturer and model shall be indicated in the test report.

6.4 Data processing

6.4.1 The in-plane resistivity of the sample is calculated according to Formula (2).

6.4.2 The through-plane resistivity of the sample is calculated according to Formulas (3) and (4).

6.4.3 The contact resistance of the sample is calculated according to Formula (5).

7 Corrosion Current Density Test of Bipolar Plate Materials

7.1 Test instrument The test instrument includes the following equipment and tools.

7.2 Preparation of sample

7.2.1 Cut the test material of a certain size as the sample, and ensure that the effective area of the sample is at least 1cm2.

7.2.2 Clean the sample surface with ethanol or other solvents; and dry it in a nitrogen environment at 80°C for 10min.

7.2.3 Seal the sample according to the opening shape on the side of the electrolytic cell to ensure that there is no leakage during the test.

7.2.4 The number of samples is 5 (ensure 3 valid values to be obtained); and there shall be no wrinkles, scratches or damage.

7.2.5 For samples from different batches, they should be sampled separately.

7.3.3 Constant potential test

7.3.3.1 Test with the sample as the working electrode, the saturated calomel electrode as the reference electrode, and the platinum sheet or platinum mesh as the auxiliary electrode. The reference electrode type can also be determined by negotiation between the two test parties; and the test potential is converted accordingly according to the used reference electrode type.

7.4 Data processing The corrosion current density of the sample is calculated according to Formula (6).

8 Area Utilization Rate Test of Bipolar Plate Component

8.1 Test instrument The test instrument includes a contour measuring instrument with an accuracy of 5µm.

8.2 Preparation of Sample

8.2.1 The sample is a complete bipolar plate with the number of 5 (ensure 3 valid values to be obtained); and there shall be no wrinkles, scratches or damage.

8.2.2 For samples from different batches, they should be sampled separately.

8.3 Test methods

8.3.1 Test at 25°C±2°C.

8.3.2 Use a transparent plate to apply a certain pressure to flatten the sample. The size of the transparent plate is larger than the sample size. The material, thickness and pressure of the transparent plate are determined by negotiation between the two test parties.

8.3.5 The membrane electrode manufacturer and model shall be indicated in the test report.

8.4 Data processing The area utilization rate of the sample is calculated according to Formula (7).

9 Thickness Uniformity Test of Bipolar Plate Component

9.1 Test instrument The test instrument includes the following equipment and tools.

9.2 Preparation of sample

9.2.1 The sample is a complete bipolar plate, with 5 samples (ensure 3 valid values to be obtained); and shall be free of wrinkles, scratches and damage.

9.2.2 For samples from different batches, they shall be sampled separately.

9.3 Test methods

9.3.1 Test at 25°C±2°C.

9.3.2 The zero point of the thickness gauge shall be calibrated before each measurement; and its zero point shall be rechecked after each sample measurement.

9.3.7 At the sample measurement position, use a thickness gauge to measure the thickness of the sealing groove edge or ridge on both sides of the sealing groove or flow field channel; and take the value on the larger side of the measurement value as the thickness of the sample.

9.4 Data processing

9.4.1 Data processing is performed on the thickness uniformity of the sample sealing area and active area, respectively.

9.4.2 The thickness uniformity of the sample is expressed by the average thickness, thickness

9.4.3 The average thickness of the sample is calculated according to Formula (8).

9.4.4 The thickness range of the sample is calculated according to Formula (9).

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 51 pages — is available in the English PDF.

Referenced standards

Normative references

GB/T 230.2 · GB/T 19466.4-2016 · GB/T 20428-2006 · GB/T 28634

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