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Standard ID | GB/T 20042.3-2022 (GB/T20042.3-2022) | Description (Translated English) | Proton exchange membrane fuel cell - Part 3: Test method for proton exchange membrane | Sector / Industry | National Standard (Recommended) | Classification of Chinese Standard | K82 | Classification of International Standard | 27.070 | Word Count Estimation | 22,224 | Date of Issue | 2022-03-09 | Date of Implementation | 2022-10-01 | Older Standard (superseded by this standard) | GB/T 20042.3-2009 | Quoted Standard | GB/T 1040.3-2006; GB/T 1446-2005; GB/T 20042.1-2017 | Drafting Organization | Shandong Dongyue Future Hydrogen Energy Materials Co., Ltd., Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Shanghai Jiaotong University, Wuhan University of Technology, Shandong Guochuang Fuel Cell Technology Innovation Center Co., Ltd., China Quality Certification Center, North China Electric Power University, Wuxi City Products Quality Supervision and Inspection Institute, Beijing Institute of Electrical Technology and Economics of Machinery Industry, Xinyuan Power Co., Ltd., Shenzhen Institute of Standards and Technology, Suzhou Kerun New Materials Co., Ltd., Shanghai Yihydro Technology Co., Ltd., Shanghai Jiehydro Technology Co., Ltd. , Beijing Hydrogen Pure Energy Technology Co., Ltd., Zhejiang Gaocheng Green Energy Technology Co., Ltd., CRRC Qingdao Sifang Locomotive and Rolling Stock Co., Ltd., Beijing Changzheng Tianmin High-Tech Co., Ltd., Wuxi Weifu High-Tech Group Co., Ltd., Great Wall Motors Baoding Hydrogen Energy Co., Ltd. | Administrative Organization | National Fuel Cell and Flow Battery Standardization Technical Committee (SAC/TC 342) | Proposing organization | China Electrical Equipment Industry Association | Issuing agency(ies) | State Administration for Market Regulation, National Standardization Administration | Summary | This standard specifies the thickness uniformity test, proton conductivity test, ion exchange equivalent test, air permeability test, tensile property test, swelling rate test and water absorption test of proton exchange membrane fuel cells. | Standard ID | GB/T 20042.3-2009 (GB/T20042.3-2009) | Description (Translated English) | Proton exchange membrane fuel cell. Part 3: Test method for proton exchange membrane | Sector / Industry | National Standard (Recommended) | Classification of Chinese Standard | K82 | Classification of International Standard | 27.070 | Word Count Estimation | 16,142 | Date of Issue | 2009-04-21 | Date of Implementation | 2009-11-01 | Quoted Standard | GB/T 1040.3-2006; GB/T 1462-2005; GB/T 6672-2001; GB/T 20042.1 | Drafting Organization | Dalian Institute of Chemical Physics, Chinese Academy of | Administrative Organization | National Fuel Cell Standardization Technical Committee | Regulation (derived from) | Announcement of Newly Approved National Standards No. 6, 2009 (No. 146 overall) | Proposing organization | China Electrical Equipment Industry Association | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | Summary | This standard specifies the proton exchange membrane fuel cell proton exchange membrane test methods and definitions of terms, thickness uniformity test, test proton conductivity, ion exchange equivalent testing, permeability testing, tensile testing, swelling and water absorption rate testing testing. This section applies to all types of proton exchange membrane. |
GB/T 20042.3-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.070
CCS K 82
Replacing GB/T 20042.3-2009
Proton exchange membrane fuel cell - Part 3: Test method
for proton exchange membrane
ISSUED ON: MARCH 09, 2022
IMPLEMENTED ON: OCTOBER 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 4
Introduction ... 6
1 Scope ... 7
2 Normative references ... 7
3 Terms and definitions... 7
4 Thickness uniformity test ... 10
4.1 Test equipment ... 10
4.2 Sample preparation and conditioning ... 10
4.3 Test method ... 10
4.4 Data processing ... 11
5 Proton conductivity test ... 12
5.1 Test equipment ... 12
5.2 Sample preparation and conditioning ... 14
5.3 Test method ... 14
5.4 Data processing ... 14
6 Equivalent weight (EW) test ... 15
6.1 Instruments and equipment ... 15
6.2 Sample preparation ... 15
6.3 Test method ... 15
6.4 Data processing ... 15
7 Air permeability test ... 16
7.1 Test equipment ... 16
7.2 Sample preparation ... 17
7.3 Test method ... 17
7.4 Data processing ... 18
8 Tensile property test ... 19
8.1 Instruments and equipment ... 19
8.2 Sample preparation and conditioning ... 19
8.3 Test method ... 20
8.4 Result representation and calculation ... 20
9 Peeling force test at 180° angle ... 21
9.1 Test equipment ... 21
9.2 Sample preparation and conditioning ... 22
9.3 Test method ... 22
9.4 Expression of sample results ... 24
10 Swelling rate test ... 24
10.1 Test equipment ... 24
10.2 Sample preparation and conditioning ... 24
10.3 Test method ... 25
10.4 Data processing ... 25
11 Water uptake test ... 26
11.1 General ... 26
11.2 Test equipment ... 26
11.3 Sample preparation ... 26
11.4 Test method ... 26
11.5 Data processing ... 27
Appendix A (Informative) Test preparation ... 28
A.1 General ... 28
A.2 Data collection and recording ... 28
Appendix B (Informative) Test report ... 29
B.1 General ... 29
B.2 Content of the report ... 29
B.3 Type of report ... 30
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, air permeability test, tensile property test, swelling rate test, and
water uptake test for proton exchange membranes used in proton exchange membrane
fuel cells.
This document applies to all types of proton exchange membranes.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this
document and are indispensable for its application. For dated references, only the
version corresponding to that date is applicable to this document; for undated references,
the latest version (including all amendments) is applicable to this document.
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
GB/T 20042.1-2017, Proton exchange membrane fuel cell - Part 1: Terminology
3 Terms and definitions
Terms and definitions determined by GB/T 20042.1-2017 and the following ones are
applicable to this document.
3.1
proton conductivity
The ability of a membrane to conduct protons, which is the reciprocal of resistivity.
Note 1: Proton conductivity is an electrochemical indicator to measure the proton
conduction capability of the membrane, which reflects the size of the proton
mobility in the membrane.
Note 2: The unit of proton conductivity is Siemens per centimeter (S/cm).
3.2
equivalent weight; EW
Dry membrane mass containing 1 mol of protons.
Note 1: It has a reciprocal relationship with IEC (Ion Exchange Capacity) which
represents the size of the ion exchange capacity, and reflects the acid
concentration in the proton exchange membrane.
Note 2: The unit of equivalent weight is grams per mole (g/mol).
3.3
tensile strength
At given temperature, humidity and tensile speed, when a tensile force is applied to a
standard membrane sample, the ratio OF the maximum tensile force that the sample
withstands before breaking TO the cross-sectional area of the sample.
Note 1: Transverse tensile strength: indicates the tensile strength of the membrane
parallel to the membrane roll axial direction, expressed by σTD.
Note 2: Longitudinal tensile strength: represents the tensile strength of the membrane
perpendicular to the direction of principal axis of the membrane roll, expressed
by σMD.
3.4
modulus of elasticity in tension
The slope of the initial straight-line portion of the stress-strain curve in a proton
exchange membrane.
Note 1: Transverse modulus of elasticity in tension: represents the modulus of elasticity
in tension of the membrane parallel to the membrane roll axial direction,
expressed by ETD.
Note 2: Longitudinal modulus of elasticity in tension: represents the modulus of
elasticity in tension of the membrane perpendicular to the direction of principal
axis of the membrane roll, expressed by EMD.
Note 3: The slope of the two points on the recommended stress-strain curve where the
strains are ε1 = 0.5% and ε2 = 2.5% is the modulus of elasticity in tension.
Note 4: The modulus of elasticity in tension is represented by E, in megapascals (MPa).
3.5
tensile strain at break
The increment per unit length of the original gauge length when the sample breaks.
Note 1: Transverse tensile strain at break: indicates the tensile strain at break of the
membrane parallel to the membrane roll axial direction, expressed by εTD.
Note 2: Longitudinal tensile strain at break: represents the tensile strain at break of the
membrane perpendicular to the direction of principal axis of the membrane
roll, expressed by εMD.
Note 3: The tensile strain at break is represented by ε, in a dimensionless ratio or
percentage (%).
3.6
peeling force at 180° angle
Under the peeling condition where the peeling angle is 180°, the load required for
continuous peeling of a test strip of certain width at a certain speed.
Note: The unit of peeling force at 180° angle is Newtons per millimeter (N/mm).
3.7
gas permeation rate
Under constant temperature and unit pressure difference, during steady permeation, the
volume of gas permeating the unit area of the sample per unit time.
Note: The gas permeation rate is expressed by the volume value under standard
temperature and pressure, and the unit is cubic centimeters per square meter day
Pa [cm3/(m2·d·Pa)].
3.8
gas permeation coefficient
Under constant temperature and unit pressure difference, during steady permeation, the
volume of gas permeating the unit thickness and unit area of the sample per unit time.
Note: The gas permeation coefficient is expressed by the volume value under standard
temperature and pressure, and the unit is cubic centimeter per square meter
second Pa [cm3·cm/(cm2·s·Pa)].
3.9
water uptake
The amount of water absorbed per unit mass of dry membrane at a given temperature.
Note: Water uptake is expressed in %.
3.10
swelling rate
Dimensional change in the transverse, longitudinal and thickness directions relative to
the dry membrane at a given temperature.
Note 1: The dimensional changes in the transverse, longitudinal and thickness
directions are recorded as TD, MD and Z axis, respectively.
Note 2: Swelling rate is expressed in %.
4 Thickness uniformity test
4.1 Test equipment
4.1.1 Thickness gauge: The accuracy is not less than 0.1 μm.
Note: See Appendix A for detailed content of test preparation.
4.1.2 Caliper: The accuracy is not less than 0.02 mm; it is used to test the length and
width of the membrane.
4.2 Sample preparation and conditioning
4.2.1 Sample preparation
The sample can be square or circular; the effective area is at least 100 cm2.
The sample shall be free of wrinkles, defects and breakage.
4.2.2 Sample conditioning
Place the samples under the condition where the temperature is 23 °C ± 2 °C and the
relative humidity is 50% ± 5% for more than 12 h.
4.3 Test method
4.3.1 The zero point of the thickness gauge shall be calibrated before each measurement,
and the zero point shall be rechecked after each sample measurement.
4.3.2 During the measurement, lower the measuring head gently to avoid deformation
of the sample. During the test, the strength of the test head applied to the surface of the
sample shall be selected between 0.7 N/cm2 and 2 N/cm2.
σ – the in-plane proton conductivity of the sample, in Siemens per centimeter (S/cm);
a – the distance between two electrodes, in centimeters (cm);
R – measured impedance of the sample, in ohms (Ω);
b – the effective length of the membrane in the direction perpendicular to the electrode,
in centimeters (cm);
d – the thickness of the sample, in centimeters (cm).
Note: Take 3 samples as a group, and calculate the average value as the test result.
6 Equivalent weight (EW) test
Note: See Appendix A for detailed content of test preparation, and Appendix B for
content of test report.
6.1 Instruments and equipment
6.1.1 Analytical balance: The division value is not less than 0.1 mg.
6.1.2 Automatic potentiometric titrator: The pH value accuracy is not less than 0.1.
6.2 Sample preparation
Take a sample whose mass is not less than 0.5 g; cut it into pieces, and place it in a
vacuum oven. Under the vacuum conditions where the absolute pressure is not higher
than 20 kPa and the temperature is 80 °C, vacuum dry it for 8 hours; move it to a
desiccator and cool it to room temperature; then, quickly weigh (complete within 30 s)
to constant weight. The difference between the two weights shall be less than 0.2 mg.
6.3 Test method
6.3.1 After taking it out of the oven, move it to a desiccator and cool it to room
temperature; immediately use an analytical balance to weigh the mass m of the dry
membrane.
6.3.2 Put the sample into a sealed reagent bottle that is filled with saturated sodium
chloride solution, and stir for 24 h.
6.3.3 Use NaOH standard solution, and use an automatic potentiometric titrator to titrate
to neutrality; record the volume VNaOH of the consumed NaOH solution.
6.4 Data processing
Calculate the EW value of the membrane according to Formula (5):
7.1.3 Water bath circulation temperature control device: The temperature control
accuracy is ±0.05 °C.
7.2 Sample preparation
7.2.1 The sample shall be representative and free of wrinkles or visible defects. The
sample is generally circular; its diameter depends on the instrument used; the number
of samples shall meet the requirements of 3 effective parallel tests.
7.2.2 Before the test, the sample shall be dried for at least 4 h at a temperature of 80 °C.
7.3 Test method
7.3.1 Separate the high-pressure chamber and the low-pressure chamber of the
differential-pressure gas permeameter, and apply vacuum grease evenly to the area
outside the test marking line of the low-pressure chamber test bench.
7.3.2 Place a piece of medium-speed qualitative filter paper, which is cut as required,
just above the central cavity of the low-pressure chamber test bench.
7.3.3 Flatly attach the prepared samples to the low-pressure chamber test bench that is
coated with grease; ensure that no air bubbles are generated in the contact area between
the sample and the grease.
7.3.4 Close the high-pressure chamber and the low-pressure chamber tightly; open the
water bath circulation; set the temperature of the temperature control device to 23 °C.
7.3.5 Turn on the power switch of the gas permeameter; open the computer operating
software of the instrument; run the replacement process of safe gas (nitrogen or other
inert gas) for a time of not less than 600 s.
7.3.6 After the replacement of the safe gas, switch the valve, and pass in high-purity
hydrogen; at the same time, turn on the vacuum pump; simultaneously evacuate and
degas the high-pressure chamber and the low-pressure chamber to below 10 Pa.
7.3.7 Close the isolation valve, open the test gas cylinder and the gas source switch, and
charge the test gas into the high-pressure chamber. The gas pressure in the high-pressure
chamber shall be within the range of 1.0×105 Pa ~ 1.1×105 Pa. When the pressure is too
high, the isolation valve shall be opened to discharge.
7.3.8 After the degassing is completed, the instrument automatically closes the exhaust
valves of the high- and low-pressure chambers and starts the air permeability test.
7.3.9 Exclude the nonlinear permeation stage at the beginning of the test, and record
the pressure change value ΔP of the low-pressure chamber and the test time t.
7.3.10 Continue the test until the pressure change of the low-pressure chamber remains
constant within the same time interval, and a stable permeation is achieved. Take at
7.4.3 For a given test apparatus, the low-pressure chamber volume V and the
penetration area S of the sample are constants.
7.4.4 The test results are expressed as the arithmetic mean of each group of samples.
8 Tensile property test
Note: See Appendix A for detailed content of test preparation, and Appendix B for
content of test report.
8.1 Instruments and equipment
8.1.1 Testing machine
Any testing machine that can meet the test requirements of this chapter is acceptable.
8.1.2 Test fixture
The test fixture shall not cause the sample to break at the fixture. When a load is applied,
the longitudinal axis of the sample shall coincide with the tensile direction passing
through the centerline of the fixture.
8.1.3 Thickness gauge and caliper
8.1.3.1 Thickness gauge: The accuracy is not less than 0.1 μm.
8.1.3.2 Caliper: The accuracy is not less than 0.02 mm; it is used to test the length and
width of the membrane.
8.2 Sample preparation and conditioning
8.2.1 The samples shall be cut at equal intervals along the longitudinal and transverse
directions of the material to be tested, and cut into dumbbells or strips of a certain size
according to the method specified in GB/T 1040.3-2006. The edge of the sample shall
be smooth without gaps. Use a low-power magnifying glass to check the gaps, and
discard samples with defective edges.
8.2.2 The samples are grouped according to each test direction, and the number of
samples in each group shall meet the requirements of 3 valid tests.
8.2.3 Accurately print or draw a marking according to the sample size requirements.
This marking shall have no effect on the sample.
8.2.4 Sample conditioning: The sample shall be placed for at least 4 h under constant
temperature and humidity conditions where the temperature is 23 °C ± 2 °C and the
relative humidity is 50% ± 5%.
9.1.2 Tensile testing machine
The tensile testing machine shall make the failure load of the sample between 15% and
85% of the full standard load. The force value indication error shall not be greater than
1%. The testing machine shall continuously peel at a rising speed of 300 mm/min ± 10
mm/min or a suitable speed, and shall be able to automatically record the relevant
displacement and load.
9.2 Sample preparation and conditioning
9.2.1 Sample preparation
The test sample is in the shape of a long strip; the longitudinal sides are parallel; the
width of the sample is 15mm ± 0.1mm, and the length is not less than 250 mm; each
group of test strips is not less than 5. Peel off the composite layer and the base material
in advance for 50 mm along the direction of the sample; there shall be no obvious
damage to the peeled part.
9.2.2 Sample conditioning
The test sample shall be placed for at least 4 h under constant temperature and humidity
conditions where the temperature is 23 °C ± 2 °C and the relative humidity is 50% ±
5%.
9.3 Test method
9.3.1 Measure the width of the test sample under constant temperature and humidity
conditions where the temperature is 23 °C ± 2 °C and the relative humidity is 50% ±
5%. The width of each sample shall be measured at 3 points within the gauge length,
and the average value shall be taken. The width measurement accuracy is ±0.5%.
9.3.2 Clamp the peeled part of the test sample on the upper and lower fixtures of the
testing machine; make the longitudinal axis of the peeled part of the test sample
coincide with the center line of the upper and lower fixtures, and clamp it. The pressure
value of the pneumatic clamp shall be selected in the range of 0.3 MPa ~ 0.7 MPa.
During the test, the unpeeled part is T-shaped with the tensile direction, as shown in
Figure 4. Record the stress-strain curve of the peeling process.
d1 – the thickness size of the sample after immersion in a constant temperature water
bath, in micrometers (μm);
d0 – the initial thickness size of the sample, in micrometers (μm).
Note 2: Take 3 samples as a group, and calculate the average value as the test result.
11 Water uptake test
Note: See Appendix A for detailed content of test preparation, and Appendix B for
content of test report.
11.1 General
This chapter specifies the method for determining the water uptake of proton exchange
membranes for fuel cells under specified dimensions, temperatures and water
immersion conditions.
The immersion temperature for the two methods specified in this chapter is 23 °C ±
2 °C and boiling water temperature is 100°C ± 2°C.
11.2 Test equipment
11.2.1 Analytical balance: The division value is 0.1 mg.
11.2.2 Oven: It can be controlled at 80 °C ± 0.2 °C.
11.2.3 Constant temperature water bath: The temperature control accuracy is ±0.2 °C.
11.3 Sample preparation
11.3.1 According to the provisions of GB/T 1446-2005, intercept a square sample
whose side length is 50 mm ± 1 mm or a circular sample whose diameter is 50 mm ± 1
mm as the sample to be tested.
11.3.2 The number of samples shall be at least 3, and there shall be no wrinkles, defects
and damage.
11.4 Test method
Place the sample in an oven at 80 °C ± 2 °C to dry for 24 h; move to a desiccator and
cool to room temperature; use an analytical balance to weigh the initial mass m0 of the
sample.
The test methods for water uptake at 23 °C and 100 °C are as follows:
......
GB/T 20042.3-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.070
K 82
Proton exchange membrane fuel cell –
Part 3. Test method for proton exchange membrane
ISSUED ON. APRIL 21, 2009
IMPLEMENTED ON. NOVEMBER 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword . 3
1 Scope .. 4
2 Normative references . 4
3 Terms and definitions . 4
4 Thickness uniformity test . 5
5 Proton conductivity test . 7
6 Ion exchange equivalent weight (EW) test . 9
7 Air permeability test .. 10
8 Tensile test . 12
9 Swelling rate test . 14
10 Water absorption test .. 16
Appendix A (Informative) Test preparation . 18
Appendix B (Informative) Test report .. 19
Proton exchange membrane fuel cell –
Part 3. Test method for proton exchange membrane
1 Scope
This part of GB/T 20042 specifies terms and definitions, thickness uniformity
test, proton conductivity test, ion exchange equivalent test, air permeability test,
tensile test, swelling ratio test, water absorption tests for the proton exchange
membrane test method for proton exchange membrane fuel cells.
This part applies to various types of proton exchange membranes.
2 Normative references
The provisions in following documents become the provisions of this part
through reference in GB/T 20042. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Standard;
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
GB/T 1040.3-2006 Plastics - Determination of tensile properties - Part 3. Test
conditions for membranes and sheets (ISO 527-3.1995, IDT)
GB/T 1462-2005 Test methods for water absorption of fiber reinforced
plastics
GB/T 6672-2001 Plastics membrane and sheeting - Determination of
thickness by mechanical scanning (ISO 4593.1993, IDT)
GB/T 20042.1 Proton exchange membrane fuel cell - Terminology
3 Terms and definitions
The terms and definitions defined in GB/T 20042.1 and the following terms and
definitions apply to this part.
3.1
Proton conductivity
4.1.1 Thickness gauge. The precision is 0.1 μm, which is used to test the
membrane thickness of the thickness 10 μm ~ 200 μm.
4.1.2 Caliper. The precision is 0.01 mm, which is used to test the length and
width of the membrane.
4.2 Sample preparation
The sample can be square or round, with an effective area of at least 100 cm2.
The sample shall be free from wrinkles, defects, or damages.
4.3 Test methods
4.3.1 PLACE the sample at a temperature of 25 °C ± 2 °C and a relative
humidity of 50% ± 5% for 12 hours.
Note. The constant temperature and humidity conditions for placing the sample
can also be determined through consultation between the supplier and
purchaser.
4.3.2 Before each measurement, it shall calibrate the zero point of the thickness
gauge, check the zero point again after the measurement of each specimen.
4.3.3 Slowly LOWER down the measurement head during measurement to
avoid deformation of the sample. During the test process, SELECT the strength
applied by the test head onto the sample surface between 0.7 N/cm2 ~ 2 N/cm2.
Note. DuPont NRE212 membrane test thickness is 53.5 μm when the test head
strength is applied to the surface of the sample is 1.75 N/cm2.
4.3.4 PERFORM test in a constant temperature and humidity environment with
a temperature of 25 °C ± 2 °C and a relative humidity of 50% ± 5%. The number
of test points per 100 cm2 of sample is not less than 9 and are evenly distributed,
the distance from the test point to the edge of the sample shall be greater than
5 mm.
4.4 Data processing
The thickness uniformity of the sample is expressed by the difference between
the maximum thickness and the minimum thickness as well as the relative
thickness deviation.
4.4.1 The difference between the maximum value and the minimum value is
calculated in accordance with formula (1).
Where.
5.3 Test methods
5.3.1 At the constant temperature and humidity conditions of 25 °C ± 2 °C and
relative humidity of 50% ± 5%, USE the thickness gauge to measure the sample
thickness, TAKE the average value of three points as the calculated thickness
d value.
5.3.2 FIX the sample in the conductivity measuring pool as shown in Figure 1,
USE a torque wrench to tighten the bolt at a torque of 3 N•m. Then PLACE the
conductivity measuring pool in a constant temperature and humidity
environment with a temperature of 25 °C ± 2 °C and a relative humidity of 50%
± 5%. At the frequency range of (1 ~ 2 × 106) Hz and a disturbance voltage of
10 mV, USE the electrochemical impedance tester to measure the impedance
spectrogram of the sample.
5.4 Data processing
In the measured impedance spectrogram, READ the impedance value (R) of
the sample from the intersection point of the high-frequency part of the spectral
line with the real axis, USE the formula (4) to calculate the proton conductivity
of the sample.
Where.
σ - The proton conductivity of the sample, in units of Siemens per centimeter
(S/cm);
α - Distance between two electrodes, in centimeters (cm);
R - The measured impedance of the sample, in the unit of ohm (Ω);
b - The effective length of the membrane in the direction perpendicular to the
electrode, in centimeters (cm);
d - The thickness of the sample, in centimeters (cm).
TAKE 3 samples as a group, CALCULATE the average value as the test result.
6 Ion exchange equivalent weight (EW) test
6.1 Instruments and equipment
6.1.1 Analytical balance. The precision is 0.1 mg.
6.1.2 Automatic potentiometric titrator. pH precision is not less than 0.1.
8.1.2 Test fixture
The test fixture shall not cause the specimen to break at the fixture. When the
load is applied, the longitudinal axis of the specimen shall be matched with the
direction of tensioning through the center line of the fixture.
8.1.3 Thickness gauges and calipers
8.1.3.1 Thickness gauge. The precision is not less than 0.1 μm. It is used to test
the thickness of the membrane with a thickness of 10 μm ~ 200 μm.
8.1.3.2 Caliper. The precision is not less than 0.01 mm, which is used to test
the length and width of the membrane.
8.2 Sample preparation
8.2.1 Samples shall be cut at equal intervals along two directions of the length
(x-direction) and width (y-direction) of the test material, cut to a certain size of
dumbbell or bar shape in accordance with GB/T 1040.3-2006. The edge of the
sample shall be smooth and unnotched, the notch can be inspected with a low-
magnification magnifier, the samples with defective edges can be discarded.
8.2.2 Samples are grouped in accordance with each test direction. The number
of samples in each group shall meet the requirements of 3 valid tests.
8.2.3 Accurately PRINT or DRAW markings as required by the size of the
sample. This marking shall not have any effect on the sample.
8.2.4 PLACE the sample at a constant temperature and humidity of 25 °C ±
2 °C and relative humidity of 50% ± 5% for at least 4 h. Placement conditions
can also be agreed by the parties involved.
8.3 Test methods
8.3.1 Under constant temperature and humidity conditions with a temperature
of 25 °C ± 2 °C and a relative humidity of 50% ± 5%, MEASURE the thickness
of the sample. The thickness and width of each sample shall be measured in
the gauge length at three points and the average value taken. The thickness
measurement precision is ± 0.2% and the width measurement precision is ±
0.5%.
8.3.2 PLACE the sample in the test fixture, so that the longitudinal axis of the
sample coincides with the center connection line of the upper and lower fixtures,
CLAMP it tightly. The pressure value of the pneumatic clamp is selected within
the range of 0.3 MPa ~ 0.7 MPa.
8.3.3 The tensile speed of the testing machine is selected within the range of
50 mm/min ~ 200 mm/min.
bath, in cubic microns (µm3);
V0 - The initial volume of the sample, in cubic microns (µm3).
TAKE 3 samples as a group, CALCULATE the average value as the test result.
If the difference in the swelling rate between any two samples in a group of
samples exceeds 5%, it shall find the cause and make determination again.
10 Water absorption test
REFER to the method specified in GB/T 1462-2005.
10.1 Overview
This part specifies the method for the determination of the amount of water
absorbed by a proton exchange membrane for fuel cells at a specified size,
temperature, and immersion time.
The immersion temperatures for the two methods specified in this part are 25 °C
± 2 °C and boiling water temperature 100 °C ± 2 °C.
10.2 Test instruments
10.2.1 Analytical balance. The precision is 0.1 mg.
10.2.2 Oven. It can be controlled at 80 °C ± 2 °C or other mutually agreed
temperature.
10.2.3 Constant temperature water bath. The temperature control precision is
± 0.2 °C.
10.3 Sample preparation
10.3.1 CUT a square or round test material of a certain size as a sample.
10.3.2 The number of samples shall be at least 3 and shall be free from wrinkles,
defects and damages.
10.4 Test methods
10.4.1 After the sample is dried in an oven at 80 °C ± 2 °C for 24 h, TRANSFER
it to a desiccator to cool it to room temperature. USE an analytical balance to
weigh the initial mass W0 of the sample.
10.4.2 PLACE the sample in a constant temperature water bath at a given
temperature for a minimum of 24 h.
Appendix A
(Informative)
Test preparation
A.1 Overview
This Appendix describes the typical items that sh...
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