GB/T 31886.2-2015Test method about the influence of gaseous contaminant(s) in reaction gas on the performance of proton exchange membrane fuel cells——Part 2: Gaseous contaminant(s) in hydrogen (English PDF)

3.1 Clean air

The air that contains various contaminants whose concentrations do not exceed the annual average primary concentration limit specified in 4.2 of GB 3095-2012.

NOTE 1. the definition of clean air in this Standard is only for its use as a fuel cell oxidant.

NOTE 2. the recommended clean air for this Standard is a formulated gas with oxygen concentration of 21%, balance gas of nitrogen.

3.2 Gaseous contaminants in hydrogen gas

Other gases contained in the fuel hydrogen. The applicable gaseous contaminant in this Standard is CO.

3.3 Fuel cell poisoning

The phenomenon of voltage attenuation of fuel cell caused by the gaseous contaminants in the reaction gas.

NOTE: all "poisoning" in this Standard refers to "fuel cell poisoning".

3.4 Poisoning operation

The process of operating that the fuel cell adopts the reaction gas containing the gaseous contaminants.

NOTE 1. the definition of poisoning in this Standard is only for fuel cell.

NOTE 2. the contaminants indicate the gas components that may cause the poisoning of the fuel cell.

4.1 Test bench of fuel cell

According to the provisions of 6.1 sample preparation and 6.2 test instrument and device in GB/T 20042.5-2009, the basic information of fuel cell under test is provided as follows.

--- The effective area of the sample membrane electrode is 50cm²; the surrounding area outside the effective area shall be sealed;

--- The flow filed plate adopts pure graphite plate with a serpentine flow filed;

--- The collector plate adopts the silver or gold coated stainless steel plate;

--- Fuel cell manufacturer provides cathode anode catalytic layer platinum load.

5.2 Determination of test conditions

According to the atmospheric pressure test method specified in 6.7 of GB/T 20042.5-2009, the following test conditions shall be determined.

--- The type of the used contaminants (X) and target contaminant volume fraction (cXd);

--- The operating temperature of fuel cell. 75°C;

--- The test current densities are. 200 mA/cm2, 500 mA/cm2 and 800 mA/cm2;

--- The lowest voltage for the fuel cell operating (Umin). 0.3V;

--- The longest poisoning time (tdmax). 10h;

--- The fuel gas outlet back pressure is 0MPa, stoichiometric ratio is 1.2; relative humidity is 100%;

--- The oxidant outlet back pressure is 0MPa, stoichiometric ratio is 2.5; relative humidity is 100%;

--- The continuous sampling interval for each parameter during the test shall not exceed 1min; thereof, the continuous sampling interval of voltage and current shall not exceed 10s.

5.3 Preparation of reaction gas

Pure hydrogen. take the hydrogen, the quality of which shall be above that required by GB/T 3634.2-2011 as the pure hydrogen source for test.

Clean air of oxidant. prepare enough clean air as the air source required by the test.

Gaseous contaminant of hydrogen before dilution. according to the provisions of GB/T 5274 and GB/T 5275.10, prepare the standard and enough gaseous contaminant of Where. Qa1 - pure hydrogen intake flow on steady state phase; Q'a1 - hydrogen with contaminant intake flow before dilution;

Qa - total air intake flow; d - dilution ration of hydrogen with contaminant.

6.2.3.2 End of poisoning phase

When the fuel cell is operated under poisoning conditions to reach one of the following conditions, the poisoning test is terminated; record the test end time to be tc. The end conditions are as follows.

a) Reach the fuel cell poison voltage platform area and continue to operate in the voltage platform area for more than 60min; the maximum fluctuation range of the fuel cell voltage in the area doesn't exceed ±15mV; the average difference of voltage within any 2min shall not exceed 5mV;

b) The fuel cell voltage reaches the minimum operating voltage (Umin) of 0.3V;

c) The fuel cell is operated to the maximum poisoning time (tdmax) of 10h.

6.2.4 Recovery phase

After the completion of the anti-poisoning test, switch the fuel hydrogen into pure hydrogen to continue the test for 5h; recover the verification against the fuel cell (during such switching process, the fuel cell mustn't be unloaded or shutdown).

6.3 Data processing

6.3.1 General

The test in this Standard is performed under constant current; when judging the fuel cell performance before and after the poisoning, the voltage change shall be taken as the reference basis. According to the data of this test, the average voltage on steady state phase, average voltage after poisoning, average poisoning time, and attenuation amplitude can be calculated.

6.3.2 Steady state performance (Uw)

The arithmetic mean value of the voltage of the fuel cell sample i in the steady state operating phase shall be calculated as per the Formula (4); it is used to characterize […]