This part of GB/T 20042 specifies the terms and definitions of the test method for membrane electrode assembly (MEA) of proton exchange membrane fuel cell, as well as thickness uniformity test, platinum loading test, single-cell polarization curve test, hydrogen crossover current density test, activation overpotential and ohmic overpotential tests, and electrochemical active surface area test.
This part is applicable to all types of proton exchange membrane fuel cells.
2 Normative references
The following documents contain provisions which, through reference in this part of GB/T 20042, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GB/T 6672-2001 Plastics film and sheeting - Determination of thickness by mechanical scanning (ISO 4593:1993, IDT)
GB/T 19596 Terminology of electric vehicles (GB/T 19596-2004, ISO 8713:2002, NEQ)
GB/T 20042.1 Proton exchange membrane fuel cell - Terminology
3 Terms and definitions
For the purposes of this part, the terms and definitions given in GB/T 19596 and GB/T 20042.1 apply.
3.1
platinum loading
the amount of precious metal Pt on the membrane electrode per unit area, expressed in mg/cm2
3.2
reactant stoichiometry
the ratio of the actual supply amount of gaseous reactant to the amount of gaseous reactant required for the actual output current of a single cell calculated according to the Faraday's law
Note: The gaseous reactant utilization and the stoichiometry are reciprocal with each other.
3.3
hydrogen crossover current density
the speed of hydrogen passing through the membrane electrode measured by electrochemical method under certain conditions of temperature, pressure and relative humidity, expressed in A/cm2
3.4
electrochemical area (ECA)
the active specific surface area of the catalyst tested electrochemically in the membrane electrode, expressed in m2/g
Note: ECA of membrane electrode is related to factors such as electrocatalyst activity and electrode structure of proton exchange membrane fuel cell (PEMFC).
