IEC 62282-7-2:2021

Fuel cell technologies - Part 7-2: Test methods - Single cell and stack performance tests for solid oxide fuel cells (SOFCs)

IEC 62282-7-2:2021 applies to SOFC cell/stack assembly units, testing systems, instruments and measuring methods, and specifies test methods to test the performance of SOFC cells and stacks. This document is not applicable to small button cells that are designed for SOFC material testing and provide no practical means of fuel utilization measurement. This document is used based on the recommendation of the entity that provides the cell performance specification or for acquiring data on a cell or stack in order to estimate the performance of a system based on it. Users of this document can selectively execute test items suitable for their purposes from those described in this document. This first edition cancels and replaces IEC TS 62282-7-2 published in 2014. This edition includes the following significant technical changes with respect to IEC TS 62282­7-2:2014:
- users can substitute selected test methods of this document with equivalent test methods of IEC 62282-8-101 for solid oxide cell (SOC) operation for energy storage purposes, operated in reverse or reversible mode;
- terms and definitions are aligned with the corresponding terms and definitions in IEC 62282-8-101;
- symbols are aligned with the corresponding symbols in IEC 62282-8-101.

Technologies des piles à combustible - Partie 7-2: Méthodes d’essai - Essais de performance de cellule élémentaire et de pile pour les piles à combustible à oxyde solide (SOFC)

IEC 62282-7-2:2021 s’applique aux entités d'assemblage de cellules/piles SOFC, aux systèmes d'essai, aux instruments et aux méthodes de mesure, et spécifie des méthodes d'essai afin de vérifier les performances des cellules et des piles SOFC. Le présent document n'est pas applicable aux petites piles boutons qui sont conçues pour les essais de matériaux SOFC et ne prévoient aucun moyen pratique de mesure de l'utilisation de combustible.
Le présent document est utilisé en réponse à la recommandation de l'entité qui fournit la spécification des performances des cellules ou pour l'acquisition de données sur une cellule ou une pile afin d'estimer les performances d'un système sur la base de ces données. Dans ce but, les utilisateurs du présent document peuvent choisir d'exécuter des éléments d'essai parmi ceux qui sont décrits ici.Cette première édition annule et remplace l'IEC TS 62282-7-2 parue en 2014. Cette édition inclut les modifications techniques majeures suivantes par rapport à l’IEC TS 62282-7-2:2014:
- les utilisateurs peuvent remplacer les méthodes d’essai sélectionnées du présent document par les méthodes d’essai équivalentes de l’IEC 62282-8-101 pour l’utilisation des piles à oxyde solide (SOC – solid oxide cell) à des fins de stockage de l’énergie, en mode inversé ou réversible;
- les termes et définitions sont alignés sur les termes et définitions correspondants de l’IEC 62282-8-101;
- les symboles sont alignés sur les symboles correspondants de l’IEC 62282-8-101.

General Information

• Status: Published
• Publication Date: 20-May-2021
• ICS: 27.070 - Fuel cells
• Technical Committee: TC 105 - Fuel cell technologies
• Drafting Committee: MT 103 - TC 105/MT 103
• Current Stage: DELPUB - Deleted Publication
• Start Date: 07-Mar-2025
• Completion Date: 30-Jun-2023

Relations

• Replaces: IEC TS 62282-7-2:2014 - Fuel cell technologies - Part 7-2: Test methods - Single cell and stack performance tests for solid oxide fuel cells (SOFC)
• Effective Date: 05-Sep-2023
• Revised: IEC 62282-7-2:2025 - Fuel cell technologies - Part 7-2: Test methods - Single cell and stack performance tests for solid oxide fuel cells (SOFCs)
• Effective Date: 05-Sep-2023

Overview

IEC 62282-7-2:2021 - Fuel cell technologies – Part 7-2: Test methods – Single cell and stack performance tests for solid oxide fuel cells (SOFCs) - specifies standardized test methods for evaluating the electrical, thermal and fuel-utilization performance of SOFC cells and stacks. The standard covers test system configuration, required instruments and measurement methods, test procedures (rating, I‑V curves, fuel/oxygen utilization, durability, thermal cycling, internal reforming and impedance analysis), and test reporting. Small button cells used only for material screening are explicitly excluded.

Key topics and technical requirements

• Test system and subsystems: Requirements for cell/stack assembly units, gas supply and manifolding, electrical connections, heaters and controls needed to reproduce repeatable SOFC test conditions.
• Instruments & measurement methods: Guidance on instrument selection, measurement uncertainties, and methods for measuring anode/cathode gas composition, cell/stack temperature, voltage, current, total impedance and mechanical loading.
• Standard test procedures: Defined steps for initial conditioning, rated power tests, current–voltage (I‑V) characteristics, effective fuel utilization dependency, long‑term durability, thermal cycling durability, internal reforming performance and resistance component identification.
• Data, stability & uncertainty: Criteria for stable operating states, data acquisition practices, calculation methods (e.g., effective fuel/oxygen utilization), and requirements for uncertainty evaluation and reporting.
• Safety and applicability: General safety conditions for test setups and clear scope limitations; users may selectively apply relevant test items.
• Alignment with related SOC/SOFC documents: Allows substitution of selected methods with equivalent tests from IEC 62282-8-101 for reversible solid oxide cell (SOC) operation; terms and symbols align with IEC 62282-8-101.

Practical applications and who uses this standard

• Manufacturers and OEMs: To validate cell/stack performance claims, set product specifications, and support quality control.
• Test laboratories and certification bodies: For standardized, repeatable performance and durability testing and for producing comparable test reports.
• System integrators and developers: To estimate system-level performance from cell/stack data (e.g., rated power, fuel utilization) and support system design choices.
• R&D groups and universities: To benchmark new materials, cell designs, and internal reforming strategies under agreed procedures.
• Investors and procurement teams: To assess technical risk, lifetime expectations and comparability between suppliers.

Related standards

• IEC 62282 series - Fuel cell technologies (general family)
• IEC 62282-8-101 - Test methods and definitions for solid oxide cell (SOC) reversible operation (noted as an allowable substitution source in this edition)

Keywords: IEC 62282-7-2, SOFC test methods, solid oxide fuel cells, single cell and stack performance, I‑V characteristics, durability testing, effective fuel utilization, testing system, instrument uncertainty.

Standards Content (Sample)

IEC 62282-7-2 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
Fuel cell technologies –
Part 7-2: Test methods – Single cell and stack performance tests for solid oxide
fuel cells (SOFCs)
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IEC 62282-7-2 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
Fuel cell technologies –
Part 7-2: Test methods – Single cell and stack performance tests for solid oxide

fuel cells (SOFCs)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.070 ISBN 978-2-8322-9805-3

– 2 – IEC 62282-7-2:2021  IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and symbols. 8
3.1 Terms and definitions . 8
3.2 Symbols . 10
4 General safety conditions . 11
5 Cell/stack assembly unit . 11
6 Testing system . 12
6.1 Subsystems in testing system . 12
6.2 Maximum variation in control items of testing system . 13
7 Instruments and measurement methods . 14
7.1 General . 14
7.2 Instrument uncertainty . 14
7.3 Anode gas . 14
7.4 Cathode gas . 17
7.5 Output voltage . 18
7.6 Output current . 18
7.7 Cell/stack assembly unit temperature . 18
7.8 Mechanical load . 18
7.9 Total impedance . 18
7.10 Ambient conditions. 19
8 Test preparation . 19
8.1 General . 19
8.2 Standard test conditions and test range . 19
8.3 Components and impurities of anode gas and cathode gas . 20
8.4 Basis of the test procedure . 20
8.5 Confirmation of aging conditions of unit . 20
8.6 Confirmation of criteria of stable state . 20
8.7 Data acquisition method . 20
9 Test procedure . 20
9.1 Set-up . 20
9.2 Initial conditioning . 21
9.3 Shut-down . 21
10 Performance test . 21
10.1 Rated power test . 21
10.2 Current-voltage characteristics test . 22
10.3 Effective fuel utilization dependency test . 23
10.4 Long term durability test . 24
10.5 Thermal cycling durability test . 25
10.6 Internal reforming performance test . 26
10.7 Resistance components identification test . 27
11 Test report . 28
11.1 General . 28

11.2 Report items . 28
11.3 Test unit data description . 29
11.4 Test conditions description. 29
11.5 Test data description . 29
11.6 Uncertainty evaluation . 29
Annex A (informative) Example of cell assembly unit . 30
Annex B (informative) Calculation of effective fuel utilization . 31
B.1 General . 31
B.2 Calculation method . 31
B.3 Calculation examples . 32
Annex C (informative) Calculation of effective oxygen utilization . 34
C.1 General . 34
C.2 Calculation method . 34
C.3 Calculation example . 35
Annex D (informative) Maximum width of the voltage hysteresis in I‑V characteristics test . 36
Annex E (informative) Current-voltage characteristics test under constant effective
fuel utilization . 37
Annex F (informative) Test report (template) . 38
F.1 Overview. 38
F.2 General information . 38
F.3 Test unit data description . 38
F.4 Test conditions . 39
F.5 Rated power test . 39
F.6 Current-voltage characteristics test . 39
F.7 Effective fuel utilization dependency test . 40
F.8 Long-term durability test . 41
F.9 Thermal cycling durability test . 42
F.10 Internal reforming performance test . 42
F.11 Resistance components identification test . 43
Annex G (informative) Method for determining instrument uncertainty . 44
Bibliography . 45

Figure 1 – Testing system . 12
Figure 2 – Typical diagram of complex impedance plot for SOFC . 28
Figure A.1 – Example of cell assembly unit . 30
Figure D.1 – Voltage hysteresis at a given sweep rate in I-V characteristics test . 36
Figure E.1 – Example of the record in current-voltage characteristics test under
constant effective fuel utilization . 37

Table 1 – Symbols . 10
Table B.1 − n for representative fuels . 32
j
Table B.2 − Anode gas composition, flow rate of each fuel component q , and n q . 32
j j j
Table C.1 − Cathode gas composition, q , and I . 35
O2 theory
– 4 – IEC 62282-7-2:2021  IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUEL CELL TECHNOLOGIES –
Part 7-2: Test methods – Single cell and
stack performance tests for solid oxide fuel cells (SOFCs)

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62282-7-2 has been prepared by IEC technical committee 105: Fuel cell technologies. It
is an International Standard.
This first edition cancels and replaces IEC TS 62282-7-2 published in 2014.
This edition includes the following significant technical changes with respect to
IEC TS 62282-7-2:2014:
a) users can substitute selected test methods of this document with equivalent test methods
of IEC 62282-8-101 for solid oxide cell (SOC) operation for energy storage purposes,
operated in reverse or reversible mode;
b) terms and definitions are aligned with the corresponding terms and definitions in
IEC 62282-8-101;
c) symbols are aligned with the corresponding symbols in IEC 62282-8-101.

The text of this International Standard is based on the following documents:
FDIS Report on voting
105/847/FDIS 105/851/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,
available at www.iec.ch/members_experts/refdocs. The main document types developed by
IEC are described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 62282 series, published under the general title Fuel cell
technologies, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 62282-7-2:2021  IEC 2021
INTRODUCTION
This part of IEC 62282 specifies test methods for a single cell and stack (denoted as
"cell/stack" hereafter) that is required in power generation systems using solid oxide fuel cells
(SOFCs).
SOFCs have a broad range of geometry and size. As such, in general, peripherals like current
collectors and gas manifolds are unique to each cell or stack and are often incorporated into a
cell or stack to form one integrated unit. In addition, they tend to have a significant effect on
the power generation characteristics of the cell or stack. This document therefore introduces
as its subject "cell/stack assembly units", which are defined as those units containing not only
a cell or stack but also peripherals.

FUEL CELL TECHNOLOGIES –
Part 7-2: Test methods – Single cell and
stack performance tests for solid oxide fuel cells (SOFCs)

1 Scope
This part of IEC 62282 applies to SOFC cell/stack assembly units, testing systems,
instruments and measuring methods, and specifies test methods to test the performance of
SOFC cells and stacks.
This document is not applicable to small button cells that are designed for SOFC material
testing and provide no practical means of fuel utilization measurement.
This document is used based on the recommendation of the entity that provides the cell
performance specification or for acquiring data on a cell or stack in order to estimate the
performance of a system based on it. Users of this document can selectively execute test
items suitable for their purposes from those described in this document.
Users can substitute selected test methods of this document with equivalent test methods of
IEC 62282-8-101 for solid oxide cell (SOC) operation for energy storage purposes, operated
in reverse or reversible mode.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60050-485, International Electrotechnical Vocabulary (IEV) – Part 485: Fuel cell
technologies (available at http://www.electropedia.org)
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
IEC 60584-3, Thermocouples – Part 3: Extension and compensating cables – Tolerances and
identification system
IEC 61515, Mineral insulated metal-sheathed thermocouple cables and thermocouples
ISO 5168, Measurement of fluid flow – Procedures for the evaluation of uncertainties
ISO 6141, Gas analysis – Contents of certificates for calibration gas mixtures
ISO 6142-1, Gas analysis – Preparation of calibration gas mixtures – Gravimetric method for
Class I mixtures
ISO 6143, Gas analysis – Comparison methods for determining and checking the composition
of calibration gas mixtures
ISO 6145-7, Gas analysis – Preparation of calibration gas mixtures using dynamic methods –
Part 7: Thermal mass-flow controllers

– 8 – IEC 62282-7-2:2021  IEC 2021
ISO 6974 (all parts), Natural gas – Determination of composition with defined uncertainty by
gas chromatography
ISO 7066-2, Assessment of uncertainty in the calibration and use of flow measurement
devices – Part 2: Non-linear calibration relationships
ISO 8573-1, Compressed air – Part 1: Contaminants and purity classes
ISO 8756, Air quality – Handling of temperature, pressure and humidity data
ISO 12185, Crude petroleum and petroleum products – Determination of density – Oscillating
U-tube method
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-485 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
cell/stack assembly unit
unit including a single cell or stack, as well as gas supply parts, current collector parts, and
any other peripherals as required for power generation tests
3.1.2
active electrode area
geometric electrode area upon which an electrochemical reaction occurs
Note 1 to entry: Usually this is the smaller of the anode and cathode areas.
3.1.3
current density
current divided by the active electrode area
3.1.4
average repeating unit voltage
cell/stack assembly unit voltage divided by the number of the cells in a series connection in
the unit
3.1.5
standard temperature and pressure
STP
temperature of 0 °C and an absolute pressure of 101,325 kPa, respectively
3.1.6
anode gas
gas that is supplied to the inlet of the anode of a single cell/stack assembly unit
Note 1 to entry: Such a gas belongs to one of the following categories:
a) pure hydrogen or mixture that contains hydrogen as a principal component with water vapour or nitrogen;

b) reformed gas of raw fuel of SOFC such as methane or kerosene premixed with water vapour or air as oxidant;
c) simulated gas of reformate that contains hydrogen, water vapour, carbon monoxide, carbon dioxide, methane,
nitrogen, etc., as main components;
d) methane, alcohols and other raw fuels directly supplied in pure form or mixed with water vapour and/or air.
3.1.7
cathode gas
gas that is supplied to the inlet of the cathode of a single cell/stack assembly unit
Note 1 to entry: Oxygen and nitrogen are its main components.
3.1.8
current collector
conductive material in a fuel cell that collects electrons from the anode side or conducts
electrons to the cathode side
3.1.9
stable state
condition of a cell/stack assembly unit at which the unit is stable enough for any controlling
parameter and the output voltage or output current of the unit to remain within its tolerance
range of variation
3.1.10
theoretical current
current when the supplied anode gas or cathode gas is completely consumed in
electrochemical reactions divided by the number of cells in a series connection
3.1.11
effective fuel utilization
ratio of the actual output current of the cell/stack assembly unit to the theoretical current
Note 1 to entry: The effective utilization is the utilization of reactants in the electrochemical reaction due to the
actual current. This may be less than the actual or total utilization if there are gas inlet and cross leaks.
Note 2 to entry: Causes of less-than-optimal currents include losses due to electronic conduction within the
cell/stack assembly, gas leaks and anode gas pass-through.
Note 3 to entry: A calculation method of effective fuel utilization is given in Annex B.
3.1.12
effective oxygen utilization
ratio of the actual output current of the cell/stack assembly unit to the theoretical current
Note 1 to entry: The effective utilization is the utilization of reactants in the electrochemical reaction due to the
actual current. This may be less than the actual or total utilization if there are gas inlet and cross leaks.
Note 2 to entry: A calculation method of effective oxygen utilization is given in Annex C.
3.1.13
maximum effective fuel utilization
highest effective fuel utilization that the unit can operate at, without causing unacceptable
degradation
Note 1 to entry: The acceptable degradation rate is usually obtained from the developer.
3.1.14
minimum cell/stack assembly unit voltage
lowest cell/stack assembly unit voltage specified by the manufacturer

– 10 – IEC 62282-7-2:2021  IEC 2021
3.1.15
open circuit voltage
OCV
voltage across the terminals of a fuel cell with cathode and anode gases present and in the
absence of external current flow
Note 1 to entry: Also known as "no-load voltage".
3.1.16
power density
ratio of the power to the active electrode area of a cell/stack assembly unit
Note 1 to entry: Power density is calculated from the voltage multiplied by the current density (P = V × J, where J
d
is current density).
3.1.17
total impedance
frequency-dependent losses due to ohmic, activation, diffusion, concentration effects, stray
(parasitic) capacitance and inductances
3.1.18
total resistance
real part of the low-frequency limit of total impedance
3.1.19
stoichiometric ratio
ratio between the number of moles of reactant gas flowing per unit time to that needed by the
electrochemical reaction
Note 1 to entry: The terms, "stoichiometric ratio" and "reactant gas utilization," are related. The reciprocal of the
fraction of the gas utilized is the stoichiometric ratio.
3.2 Symbols
Table 1 lists the symbols and units that are used in this document.
Table 1 – Symbols
Symbol Definition Unit
a
a Error limit specified from specification of instrument
I Current A
J Current density A/cm
n Number of transferred electrons
N Number of cells in a series connection
p Absolute pressure of anode gas kPa
a
p Absolute pressure of cathode gas kPa
c
P Output power W
P Output power density W/cm
d
q Flow rate of anode gas l/min (STP)
a
q Flow rate of cathode gas l/min (STP)
c
q Flow rate of fuel component j in anode gas l/min (STP)
j
t Time s, min, h
T Cell/stack assembly unit operating temperature °C
op
a
u Combined standard uncertainty for instruments
I
a
u Standard uncertainty for instrument i
I,i
Symbol Definition Unit
U Effective fuel utilization %
f
U Effective oxygen utilization %
O2
a
U Extended instrument uncertainty
I
V Voltage V
b
x Molar fraction of component i or Mole percent of component i mol/mol or mol %
i
c Concentration of component i mol/m

i
ξ Hydrocarbon conversion rate for hydrocarbon component j %
j
a
Denotes where the unit varies depending on the specification.
b
Mole percent expressed as one hundred times mole fraction.

4 General safety conditions
An operating fuel cell uses oxidizing and combustible gases. Typically, these gases are stored
in high-pressure containers. The fuel cell itself may be operated at pressures greater than
atmospheric pressure. Those who carry out cell/stack assembly unit testing shall be trained
and experienced in the operation of test systems and specifically in safety procedures
involving electrical equipment and reactive, compressed gases.
The test personnel are responsible for obtaining and following all applicable safety codes and
generally accepted engineering practices related to their test system, facility, fuels (with
particular attention to compressed gases), and exhaust products.
Materials which are compatible with the use and storage of the reactant gases shall be used
during testing. Local safety codes and standards for working with hydrogen, hydrocarbons
and carbon monoxide should be followed.
In summary, safely operating a test station requires appropriate technical training and
experience as well as safety facilities and equipment, all of which are outside the scope of
this document.
5 Cell/stack assembly unit
A cell/stack assembly unit includes a cell or stack, gas supply, current leads, and such other
peripherals as required for power generation tests. It shall be provided with single or multiple
measuring points for temperature and voltage, and one set of current lead points, all to be
specified by the manufacturer.
As shown in Annex A, the boundary of a cell/stack assembly unit goes through the anode gas
supply port, cathode gas supply port, temperature measuring point, current lead points,
voltage measuring points and mechanical load application points.
Some cell/stack assembly units may have no exhaust port for the anode gas or cathode gas
because of the configuration of the cells. In such cases, the gas flow field pattern and its
material shall be determined by the method recommended by the manufacturer. The load
application method shall be also based on the recommendation of the manufacturer. The
maximum operating temperature from the manufacturer shall not be exceeded.
If the components of a cell/stack assembly unit other than a cell/stack are not specified by the
manufacturer, the following shall be described in the test report, as a minimum:
a) materials and geometry of the peripheral components to be used for testing;
b) flow patterns and directions of anode and cathode gases;

– 12 – IEC 62282-7-2:2021  IEC 2021
c) locations of temperature measurement, mechanical load application, voltage
measurement and current leads;
d) magnitude of the mechanical load;
e) configuration of assembly unit and its assembling method.
6 Testing system
6.1 Subsystems in testing system
6.1.1 General
As shown in Figure 1, a testing system consists of an anode gas control subsystem, cathode
gas control subsystem, cell/stack assembly unit temperature control subsystem, output power
control subsystem, measurement and data acquisition subsystem and safety subsystem. It
may also include a mechanical load control subsystem, anode gas and cathode gas pressure
control subsystem and/or a test system control subsystem that controls the whole testing
system, if needed.
Figure 1 – Testing system
6.1.2 Anode gas control subsystem
The anode gas control subsystem controls the flow rate, composition and temperature of the
anode gas supplied to the cell/stack assembly unit. If the gas composition is to be maintained
throughout the piping, then attention shall be paid to the materials, temperature, inner
diameter and length of the piping. Where necessary, the piping shall be heated and/or
thermally insulated in order to prevent condensation of water vapour.
Care should be taken to avoid other phenomena, such as carbon deposits, and the
evaporation and transport of undesired materials in the gas streams, such as chromium.
6.1.3 Cathode gas control subsystem
The cathode gas control subsystem controls the flow rate, composition and temperature of the
cathode gas supplied to the cell/stack assembly unit.

6.1.4 Cell/stack assembly unit temperature control subsystem
The cell/stack assembly unit temperature control subsystem controls, at least, the electric
furnace or the unit temperature. It maintains the operating temperature. The electric furnace
shall be selected to maintain the temperature distribution within the specified tolerance level.
Efforts should be made to minimize the electrical noise that the electric furnace generates
while providing heat. It is assumed that all the test systems will use an electrical furnace for
simplicity and safety reasons.
6.1.5 Output power control subsystem
The output power control subsystem controls the output current or output voltage of the
cell/stack assembly unit.
6.1.6 Measurement and data acquisition subsystem
The measurement and data acquisition subsystem acquires and records the cell/stack
assembly unit temperature, current, voltage, anode gas flow rate, cathode gas flow rate, and
optionally, environmental conditions (ambient temperature, relative humidity, and atmospheric
pressure) in accordance with the specified method. If necessary, it also acquires and records
the mechanical load applied to the cell; the temperature, composition and pressure of the
cathode gas and the anode gas; the flow rate, composition, temperature and pressure of
anode and cathode exhaust gases; and cell/stack assembly unit impedance data, etc., in
accordance with the specified method.
6.1.7 Safety subsystem
The safety subsystem functions as a detector and alarm system for malfunctioning of the test
system based on predefined parameters and criteria. If it detects a serious fault, then it shall
automatically establish a safe state in the test system. The anode should be purged with an
inert gas, such as nitrogen, which could also contain hydrogen at concentrations below the
lower flammability limit.
6.1.8 Mechanical load control subsystem
The optional mechanical load control subsystem regulates the mechanical load that is applied
to increase the contact among components in the cell/stack assembly unit. The subsystem
should be strong enough to apply the required mechanical load under the test conditions and
to maintain the load for long term operation.
6.1.9 Gas pressure control subsystem for anode and cathode
The optional gas pressure control subsystem for anode and cathode gases regulates the
pressure of these gases by the use of a back pressure control valve, etc.
6.1.10 Test system control subsystem
The test system control subsystem provides the integrated control for each control subsystem
and data acquisition subsystem.
6.2 Maximum variation in control items of testing system
The tolerable variation of each control item in the testing system shall fall within the following
ranges:
In the case of current control: current: ±1 % relative to rated value
point;
In the case of voltage control: voltage: ±1 % relative to set point;
Temperature: ±1,0 % relative to set point;

– 14 – IEC 62282-7-2:2021  IEC 2021
NOTE 1 Temperature variation at the set point of less than ±5 K will increase reproducibility.
Anode and cathode gas flow rates: ±1 % relative to rated;
Anode gas composition: ±2,0 mol % for H , N ;
2 2
±2,0 mol % for CO, CO , CH ;
2 4
±5,0 mol % for H O (water vapour concentration);
In case of bubbler or sparger humidification: Dew point temperature: ±1 °C;
NOTE 2 At water vapour concentrations greater than 10 mol %, a bubbler system (sparger) can cause higher
uncertainty.
Cathode gas composition: ±1,0 mol % of the target O concentration;
Where pressures of anode and cathode ±1 % of rated condition, when pressure of rated

gases are to be controlled, pressures of condition is equal to or larger than 0,3 MPa; and
anode and cathode gases: 3 kPa, when pressure of rated condition is
smaller than 0,3 MPa.
7 Instruments and measurement methods
7.1 General
Measuring instruments shall meet the requirement of 7.2. As a minimum, the flow rate and
composition of the anode and cathode gases as well as the temperature, voltage, and current
of the cell/stack assembly unit shall be measured. Additional measurements shall be taken
based on the test parameters and/or test conditions. Some of the following items specified in
7.3 or 7.4 may not be measurable in the case of a cell/stack assembly unit having no anode or
cathode gas exhaust port.
7.2 Instrument uncertainty
The expanded uncertainty of each measuring instrument (coverage factor k = 2) at the time of
calibration or that estimated from the class of instrument shall meet the following
requirements:
NOTE Coverage factor is defined in ISO/IEC Guide 98-3.
Current: ±1 % relative to rated;
Voltage: ±0,5 % relative to OCV;
Temperature: ±1,0 % of reading;
Flow rates of anode and cathode gases: ±2 % of rated;
Pressures of anode and cathode gases: ±1 % of reading;average
Anode gas composition: ±2 mol % for H , H O, and N ;
2 2 2
±1 mol % for CO, CO , and CH ;
2 4
Cathode gas composition: ±0,3 mol % for O (balance N ).
2 2
7.3 Anode gas
7.3.1 Anode gas flow rate
The anode gas flow rate shall be measured using mass flow meters, volumetric flow meters or
turbine-type flow meters. The flow meter shall be selected by taking into consideration the
species in the supplied gas, the range of flow rates, and the allowable uncertainty of the flow
meter. When measurements are made on a volumetric basis, they shall be converted to mass
flow rate by measuring the gas temperature and pressure or gas density in the vicinity of the
flow meters. Measurement uncertainty for dry gases should be evaluated in accordance with
ISO 5168 or ISO 7066-2.
7.3.2 Anode gas composition
The anode gas composition should be measured when the performance of the cell/stack
assembly unit is measured. If this is not possible, however, the anode gas composition shall
be measured during the preparation of the performance test under the same conditions as
those of the cell performance test.
When anode gas is supplied in one of the following conditions a) to d) below, and if the gas
supply line has no reactors, such as a reformer, and is confirmed to insignificantly change the
gas composition, composition may be calculated based on the composition table published by
the gas supplier and values obtained from each flow meter, in accordance with ISO 6145-7:
a) a single-composition gas such as hydrogen is supplied;
b) a mixed gas of known composition is supplied;
c) anode gas is supplied by mixing component gases in a controlled manner using multiple
flow meters;
d) gases under b) and c) above are supplied in combination.
The anode gas shall be sampled near the anode gas supply port of the cell/stack assembly
unit and analysed using an infrared spectroscopy, mass spectrometer, gas chromatograph or
similar device. The gas sample shall be transported from its origin to the point of analysis in a
manner which minimizes changes in composition. Thus, the material, temperature, diameter
and the length of the tubing shall be carefully chosen to minimize the compositional change in
the sampling tubing. When necessary, it shall be heated to avoid the condensation of the
water vapour.
If water vapour is likely to affect measurement, remove water from the gas sample or dilute
the gas sample with argon or a similar inert gas.
The result of such analysis for gas component i, expressed as c (mol/m ) shall be normalized
i
to obtain a normalized concentration, x (mol /mol), using the following equation:
i
c
i
x = (1)
i
c
∑ i
i
where c represents the sum of concentrations of all component gases in the analysis.
∑ i
i
The gas analyser shall be calibrated using a standard gas of known mass ratio.
The measurement uncertainty shall be evaluated in accordance with ISO 6974 (all parts),
ISO 6141, ISO 6142-1, or ISO 6143.
7.3.3 Anode gas temperature
The gas temperature shall be measured near the anode gas supply port of the cell/stack
assembly unit by using a thermocouple or sheathed thermocouple and an extension leadwire
of a type and class in accordance with IEC 60584-1, IEC 60584-3 or IEC 61515. When there
is a reactor such as a reformer, the gas temperature at the exit of the reactor should also be
measured.
NOTE There can be significant differences between the temperature of the tube wall and the temperature of the
bulk gas.
If it is difficult to measure the gas temperature during the cell performance test, the anode gas
temperature shall be measured during the preparation of the performance test under the same
conditions as those of the performance test.

– 16 – IEC 62282-7-2:2021  IEC 2021
7.3.4 Anode gas pressure
The anode gas pressure shall be measured upstream of the anode gas supply port of the
cell/stack assembly unit by using a calibrated pressure sensor, manometer, Bourdon tube or
similar instrument. The measuring instrument shall be located in such a manner that the
uncertainty is minimized in consideration of any pressure loss within the piping, piping
temperature and other factors. Condensation of water vapour during measurement shall be
prevented. One way may be to measure the pressure by injecting a very small amount of dry
nitrogen gas or similar into the pipe, close to the measuring instrument.
7.3.5 Anode exhaust gas flow rate
The anode exhaust gas flow rate shall be measured using mass flow meters, volumetric flow
meters or turbine-type flow meters after implementing a means to prevent water condensation
from affecting the stability of anode gas flow or after removing water from the gas flow. When
measurements are made on a volumetric basis, they shall be converted to mass flow rate by
measuring the gas temperature and pressure or gas density in the vicinity of the flow meters.
Alternatively, the anode exhaust gas flow rate can be calculated from the component
concentrations of the anode exhaust gas, tracer concentration and tracer flow rate by
precisely adding a minute amount of a gas that is not contained in the anode exhaust gas as
the tracer. The gas analyser shall be calibrated using a standard gas of known mass ratio.
Measurement uncertainty shall be evaluated in accordance with ISO 6974 (all parts),
ISO 6141, ISO 6142-1, or ISO 6143.
The exhaust gas shall be handled with caution for reasons of safety and the environment,
since it may still contain hydrogen, carbon monoxide and hydrocarbons.

7.3.6 Anode exhaust gas component
The anode exhaust gas shall be sampled near the anode gas exhaust port of the cell/stack
assembly unit. The sample shall be analysed using an infrared spectrophotometer
...

IEC 62282-7-2 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 7-2: Test methods – Single cell and stack performance tests for solid oxide
fuel cells (SOFCs)
Technologies des piles à combustible –
Partie 7-2: Méthodes d’essai – Essais de performance de cellule élémentaire et
de pile pour les piles à combustible à oxyde solide (SOFC)

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IEC 62282-7-2 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 7-2: Test methods – Single cell and stack performance tests for solid oxide

fuel cells (SOFCs)
Technologies des piles à combustible –

Partie 7-2: Méthodes d’essai – Essais de performance de cellule élémentaire et

de pile pour les piles à combustible à oxyde solide (SOFC)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.070 ISBN 978-2-8322-1037-3

– 2 – IEC 62282-7-2:2021  IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and symbols. 8
3.1 Terms and definitions . 8
3.2 Symbols . 10
4 General safety conditions . 11
5 Cell/stack assembly unit . 11
6 Testing system . 12
6.1 Subsystems in testing system . 12
6.2 Maximum variation in control items of testing system . 13
7 Instruments and measurement methods . 14
7.1 General . 14
7.2 Instrument uncertainty . 14
7.3 Anode gas . 14
7.4 Cathode gas . 17
7.5 Output voltage . 18
7.6 Output current . 18
7.7 Cell/stack assembly unit temperature . 18
7.8 Mechanical load . 18
7.9 Total impedance . 18
7.10 Ambient conditions. 19
8 Test preparation . 19
8.1 General . 19
8.2 Standard test conditions and test range . 19
8.3 Components and impurities of anode gas and cathode gas . 20
8.4 Basis of the test procedure . 20
8.5 Confirmation of aging conditions of unit . 20
8.6 Confirmation of criteria of stable state . 20
8.7 Data acquisition method . 20
9 Test procedure . 20
9.1 Set-up . 20
9.2 Initial conditioning . 21
9.3 Shut-down . 21
10 Performance test . 21
10.1 Rated power test . 21
10.2 Current-voltage characteristics test . 22
10.3 Effective fuel utilization dependency test . 23
10.4 Long term durability test . 24
10.5 Thermal cycling durability test . 25
10.6 Internal reforming performance test . 26
10.7 Resistance components identification test . 27
11 Test report . 28
11.1 General . 28

11.2 Report items . 28
11.3 Test unit data description . 29
11.4 Test conditions description. 29
11.5 Test data description . 29
11.6 Uncertainty evaluation . 29
Annex A (informative) Example of cell assembly unit . 30
Annex B (informative) Calculation of effective fuel utilization . 31
B.1 General . 31
B.2 Calculation method . 31
B.3 Calculation examples . 32
Annex C (informative) Calculation of effective oxygen utilization . 34
C.1 General . 34
C.2 Calculation method . 34
C.3 Calculation example . 35
Annex D (informative) Maximum width of the voltage hysteresis in I‑V characteristics test . 36
Annex E (informative) Current-voltage characteristics test under constant effective
fuel utilization . 37
Annex F (informative) Test report (template) . 38
F.1 Overview. 38
F.2 General information . 38
F.3 Test unit data description . 38
F.4 Test conditions . 39
F.5 Rated power test . 39
F.6 Current-voltage characteristics test . 39
F.7 Effective fuel utilization dependency test . 40
F.8 Long-term durability test . 41
F.9 Thermal cycling durability test . 42
F.10 Internal reforming performance test . 42
F.11 Resistance components identification test . 43
Annex G (informative) Method for determining instrument uncertainty . 44
Bibliography . 45

Figure 1 – Testing system . 12
Figure 2 – Typical diagram of complex impedance plot for SOFC . 28
Figure A.1 – Example of cell assembly unit . 30
Figure D.1 – Voltage hysteresis at a given sweep rate in I-V characteristics test . 36
Figure E.1 – Example of the record in current-voltage characteristics test under
constant effective fuel utilization . 37

Table 1 – Symbols . 10
Table B.1 − n for representative fuels . 32
j
Table B.2 − Anode gas composition, flow rate of each fuel component q , and n q . 32
j j j
Table C.1 − Cathode gas composition, q , and I . 35
O2 theory
– 4 – IEC 62282-7-2:2021  IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUEL CELL TECHNOLOGIES –
Part 7-2: Test methods – Single cell and
stack performance tests for solid oxide fuel cells (SOFCs)

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC
Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62282-7-2 has been prepared by IEC technical committee 105: Fuel cell technologies. It
is an International Standard.
This first edition cancels and replaces IEC TS 62282-7-2 published in 2014.
This edition includes the following significant technical changes with respect to
IEC TS 62282-7-2:2014:
a) users can substitute selected test methods of this document with equivalent test methods
of IEC 62282-8-101 for solid oxide cell (SOC) operation for energy storage purposes,
operated in reverse or reversible mode;
b) terms and definitions are aligned with the corresponding terms and definitions in
IEC 62282-8-101;
c) symbols are aligned with the corresponding symbols in IEC 62282-8-101.

The text of this International Standard is based on the following documents:
FDIS Report on voting
105/847/FDIS 105/851/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,
available at www.iec.ch/members_experts/refdocs. The main document types developed by
IEC are described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 62282 series, published under the general title Fuel cell
technologies, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 62282-7-2:2021  IEC 2021
INTRODUCTION
This part of IEC 62282 specifies test methods for a single cell and stack (denoted as
"cell/stack" hereafter) that is required in power generation systems using solid oxide fuel cells
(SOFCs).
SOFCs have a broad range of geometry and size. As such, in general, peripherals like current
collectors and gas manifolds are unique to each cell or stack and are often incorporated into a
cell or stack to form one integrated unit. In addition, they tend to have a significant effect on
the power generation characteristics of the cell or stack. This document therefore introduces
as its subject "cell/stack assembly units", which are defined as those units containing not only
a cell or stack but also peripherals.

FUEL CELL TECHNOLOGIES –
Part 7-2: Test methods – Single cell and
stack performance tests for solid oxide fuel cells (SOFCs)

1 Scope
This part of IEC 62282 applies to SOFC cell/stack assembly units, testing systems,
instruments and measuring methods, and specifies test methods to test the performance of
SOFC cells and stacks.
This document is not applicable to small button cells that are designed for SOFC material
testing and provide no practical means of fuel utilization measurement.
This document is used based on the recommendation of the entity that provides the cell
performance specification or for acquiring data on a cell or stack in order to estimate the
performance of a system based on it. Users of this document can selectively execute test
items suitable for their purposes from those described in this document.
Users can substitute selected test methods of this document with equivalent test methods of
IEC 62282-8-101 for solid oxide cell (SOC) operation for energy storage purposes, operated
in reverse or reversible mode.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60050-485, International Electrotechnical Vocabulary (IEV) – Part 485: Fuel cell
technologies (available at http://www.electropedia.org)
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
IEC 60584-3, Thermocouples – Part 3: Extension and compensating cables – Tolerances and
identification system
IEC 61515, Mineral insulated metal-sheathed thermocouple cables and thermocouples
ISO 5168, Measurement of fluid flow – Procedures for the evaluation of uncertainties
ISO 6141, Gas analysis – Contents of certificates for calibration gas mixtures
ISO 6142-1, Gas analysis – Preparation of calibration gas mixtures – Gravimetric method for
Class I mixtures
ISO 6143, Gas analysis – Comparison methods for determining and checking the composition
of calibration gas mixtures
ISO 6145-7, Gas analysis – Preparation of calibration gas mixtures using dynamic methods –
Part 7: Thermal mass-flow controllers

– 8 – IEC 62282-7-2:2021  IEC 2021
ISO 6974 (all parts), Natural gas – Determination of composition with defined uncertainty by
gas chromatography
ISO 7066-2, Assessment of uncertainty in the calibration and use of flow measurement
devices – Part 2: Non-linear calibration relationships
ISO 8573-1, Compressed air – Part 1: Contaminants and purity classes
ISO 8756, Air quality – Handling of temperature, pressure and humidity data
ISO 12185, Crude petroleum and petroleum products – Determination of density – Oscillating
U-tube method
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-485 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
cell/stack assembly unit
unit including a single cell or stack, as well as gas supply parts, current collector parts, and
any other peripherals as required for power generation tests
3.1.2
active electrode area
geometric electrode area upon which an electrochemical reaction occurs
Note 1 to entry: Usually this is the smaller of the anode and cathode areas.
3.1.3
current density
current divided by the active electrode area
3.1.4
average repeating unit voltage
cell/stack assembly unit voltage divided by the number of the cells in a series connection in
the unit
3.1.5
standard temperature and pressure
STP
temperature of 0 °C and an absolute pressure of 101,325 kPa, respectively
3.1.6
anode gas
gas that is supplied to the inlet of the anode of a single cell/stack assembly unit
Note 1 to entry: Such a gas belongs to one of the following categories:
a) pure hydrogen or mixture that contains hydrogen as a principal component with water vapour or nitrogen;

b) reformed gas of raw fuel of SOFC such as methane or kerosene premixed with water vapour or air as oxidant;
c) simulated gas of reformate that contains hydrogen, water vapour, carbon monoxide, carbon dioxide, methane,
nitrogen, etc., as main components;
d) methane, alcohols and other raw fuels directly supplied in pure form or mixed with water vapour and/or air.
3.1.7
cathode gas
gas that is supplied to the inlet of the cathode of a single cell/stack assembly unit
Note 1 to entry: Oxygen and nitrogen are its main components.
3.1.8
current collector
conductive material in a fuel cell that collects electrons from the anode side or conducts
electrons to the cathode side
3.1.9
stable state
condition of a cell/stack assembly unit at which the unit is stable enough for any controlling
parameter and the output voltage or output current of the unit to remain within its tolerance
range of variation
3.1.10
theoretical current
current when the supplied anode gas or cathode gas is completely consumed in
electrochemical reactions divided by the number of cells in a series connection
3.1.11
effective fuel utilization
ratio of the actual output current of the cell/stack assembly unit to the theoretical current
Note 1 to entry: The effective utilization is the utilization of reactants in the electrochemical reaction due to the
actual current. This may be less than the actual or total utilization if there are gas inlet and cross leaks.
Note 2 to entry: Causes of less-than-optimal currents include losses due to electronic conduction within the
cell/stack assembly, gas leaks and anode gas pass-through.
Note 3 to entry: A calculation method of effective fuel utilization is given in Annex B.
3.1.12
effective oxygen utilization
ratio of the actual output current of the cell/stack assembly unit to the theoretical current
Note 1 to entry: The effective utilization is the utilization of reactants in the electrochemical reaction due to the
actual current. This may be less than the actual or total utilization if there are gas inlet and cross leaks.
Note 2 to entry: A calculation method of effective oxygen utilization is given in Annex C.
3.1.13
maximum effective fuel utilization
highest effective fuel utilization that the unit can operate at, without causing unacceptable
degradation
Note 1 to entry: The acceptable degradation rate is usually obtained from the developer.
3.1.14
minimum cell/stack assembly unit voltage
lowest cell/stack assembly unit voltage specified by the manufacturer

– 10 – IEC 62282-7-2:2021  IEC 2021
3.1.15
open circuit voltage
OCV
voltage across the terminals of a fuel cell with cathode and anode gases present and in the
absence of external current flow
Note 1 to entry: Also known as "no-load voltage".
3.1.16
power density
ratio of the power to the active electrode area of a cell/stack assembly unit
Note 1 to entry: Power density is calculated from the voltage multiplied by the current density (P = V × J, where J
d
is current density).
3.1.17
total impedance
frequency-dependent losses due to ohmic, activation, diffusion, concentration effects, stray
(parasitic) capacitance and inductances
3.1.18
total resistance
real part of the low-frequency limit of total impedance
3.1.19
stoichiometric ratio
ratio between the number of moles of reactant gas flowing per unit time to that needed by the
electrochemical reaction
Note 1 to entry: The terms, "stoichiometric ratio" and "reactant gas utilization," are related. The reciprocal of the
fraction of the gas utilized is the stoichiometric ratio.
3.2 Symbols
Table 1 lists the symbols and units that are used in this document.
Table 1 – Symbols
Symbol Definition Unit
a
a Error limit specified from specification of instrument
I Current A
J Current density A/cm
n Number of transferred electrons
N Number of cells in a series connection
p Absolute pressure of anode gas kPa
a
p Absolute pressure of cathode gas kPa
c
P Output power W
P Output power density W/cm
d
q Flow rate of anode gas l/min (STP)
a
q Flow rate of cathode gas l/min (STP)
c
q Flow rate of fuel component j in anode gas l/min (STP)
j
t Time s, min, h
T Cell/stack assembly unit operating temperature °C
op
a
u Combined standard uncertainty for instruments
I
a
u Standard uncertainty for instrument i
I,i
Symbol Definition Unit
U Effective fuel utilization %
f
U Effective oxygen utilization %
O2
a
U Extended instrument uncertainty
I
V Voltage V
b
x Molar fraction of component i or Mole percent of component i mol/mol or mol %
i
c Concentration of component i mol/m

i
ξ Hydrocarbon conversion rate for hydrocarbon component j %
j
a
Denotes where the unit varies depending on the specification.
b
Mole percent expressed as one hundred times mole fraction.

4 General safety conditions
An operating fuel cell uses oxidizing and combustible gases. Typically, these gases are stored
in high-pressure containers. The fuel cell itself may be operated at pressures greater than
atmospheric pressure. Those who carry out cell/stack assembly unit testing shall be trained
and experienced in the operation of test systems and specifically in safety procedures
involving electrical equipment and reactive, compressed gases.
The test personnel are responsible for obtaining and following all applicable safety codes and
generally accepted engineering practices related to their test system, facility, fuels (with
particular attention to compressed gases), and exhaust products.
Materials which are compatible with the use and storage of the reactant gases shall be used
during testing. Local safety codes and standards for working with hydrogen, hydrocarbons
and carbon monoxide should be followed.
In summary, safely operating a test station requires appropriate technical training and
experience as well as safety facilities and equipment, all of which are outside the scope of
this document.
5 Cell/stack assembly unit
A cell/stack assembly unit includes a cell or stack, gas supply, current leads, and such other
peripherals as required for power generation tests. It shall be provided with single or multiple
measuring points for temperature and voltage, and one set of current lead points, all to be
specified by the manufacturer.
As shown in Annex A, the boundary of a cell/stack assembly unit goes through the anode gas
supply port, cathode gas supply port, temperature measuring point, current lead points,
voltage measuring points and mechanical load application points.
Some cell/stack assembly units may have no exhaust port for the anode gas or cathode gas
because of the configuration of the cells. In such cases, the gas flow field pattern and its
material shall be determined by the method recommended by the manufacturer. The load
application method shall be also based on the recommendation of the manufacturer. The
maximum operating temperature from the manufacturer shall not be exceeded.
If the components of a cell/stack assembly unit other than a cell/stack are not specified by the
manufacturer, the following shall be described in the test report, as a minimum:
a) materials and geometry of the peripheral components to be used for testing;
b) flow patterns and directions of anode and cathode gases;

– 12 – IEC 62282-7-2:2021  IEC 2021
c) locations of temperature measurement, mechanical load application, voltage
measurement and current leads;
d) magnitude of the mechanical load;
e) configuration of assembly unit and its assembling method.
6 Testing system
6.1 Subsystems in testing system
6.1.1 General
As shown in Figure 1, a testing system consists of an anode gas control subsystem, cathode
gas control subsystem, cell/stack assembly unit temperature control subsystem, output power
control subsystem, measurement and data acquisition subsystem and safety subsystem. It
may also include a mechanical load control subsystem, anode gas and cathode gas pressure
control subsystem and/or a test system control subsystem that controls the whole testing
system, if needed.
Figure 1 – Testing system
6.1.2 Anode gas control subsystem
The anode gas control subsystem controls the flow rate, composition and temperature of the
anode gas supplied to the cell/stack assembly unit. If the gas composition is to be maintained
throughout the piping, then attention shall be paid to the materials, temperature, inner
diameter and length of the piping. Where necessary, the piping shall be heated and/or
thermally insulated in order to prevent condensation of water vapour.
Care should be taken to avoid other phenomena, such as carbon deposits, and the
evaporation and transport of undesired materials in the gas streams, such as chromium.
6.1.3 Cathode gas control subsystem
The cathode gas control subsystem controls the flow rate, composition and temperature of the
cathode gas supplied to the cell/stack assembly unit.

6.1.4 Cell/stack assembly unit temperature control subsystem
The cell/stack assembly unit temperature control subsystem controls, at least, the electric
furnace or the unit temperature. It maintains the operating temperature. The electric furnace
shall be selected to maintain the temperature distribution within the specified tolerance level.
Efforts should be made to minimize the electrical noise that the electric furnace generates
while providing heat. It is assumed that all the test systems will use an electrical furnace for
simplicity and safety reasons.
6.1.5 Output power control subsystem
The output power control subsystem controls the output current or output voltage of the
cell/stack assembly unit.
6.1.6 Measurement and data acquisition subsystem
The measurement and data acquisition subsystem acquires and records the cell/stack
assembly unit temperature, current, voltage, anode gas flow rate, cathode gas flow rate, and
optionally, environmental conditions (ambient temperature, relative humidity, and atmospheric
pressure) in accordance with the specified method. If necessary, it also acquires and records
the mechanical load applied to the cell; the temperature, composition and pressure of the
cathode gas and the anode gas; the flow rate, composition, temperature and pressure of
anode and cathode exhaust gases; and cell/stack assembly unit impedance data, etc., in
accordance with the specified method.
6.1.7 Safety subsystem
The safety subsystem functions as a detector and alarm system for malfunctioning of the test
system based on predefined parameters and criteria. If it detects a serious fault, then it shall
automatically establish a safe state in the test system. The anode should be purged with an
inert gas, such as nitrogen, which could also contain hydrogen at concentrations below the
lower flammability limit.
6.1.8 Mechanical load control subsystem
The optional mechanical load control subsystem regulates the mechanical load that is applied
to increase the contact among components in the cell/stack assembly unit. The subsystem
should be strong enough to apply the required mechanical load under the test conditions and
to maintain the load for long term operation.
6.1.9 Gas pressure control subsystem for anode and cathode
The optional gas pressure control subsystem for anode and cathode gases regulates the
pressure of these gases by the use of a back pressure control valve, etc.
6.1.10 Test system control subsystem
The test system control subsystem provides the integrated control for each control subsystem
and data acquisition subsystem.
6.2 Maximum variation in control items of testing system
The tolerable variation of each control item in the testing system shall fall within the following
ranges:
In the case of current control: current: ±1 % relative to rated value
point;
In the case of voltage control: voltage: ±1 % relative to set point;
Temperature: ±1,0 % relative to set point;

– 14 – IEC 62282-7-2:2021  IEC 2021
NOTE 1 Temperature variation at the set point of less than ±5 K will increase reproducibility.
Anode and cathode gas flow rates: ±1 % relative to rated;
Anode gas composition: ±2,0 mol % for H , N ;
2 2
±2,0 mol % for CO, CO , CH ;
2 4
±5,0 mol % for H O (water vapour concentration);
In case of bubbler or sparger humidification: Dew point temperature: ±1 °C;
NOTE 2 At water vapour concentrations greater than 10 mol %, a bubbler system (sparger) can cause higher
uncertainty.
Cathode gas composition: ±1,0 mol % of the target O concentration;
Where pressures of anode and cathode ±1 % of rated condition, when pressure of rated

gases are to be controlled, pressures of condition is equal to or larger than 0,3 MPa; and
anode and cathode gases: 3 kPa, when pressure of rated condition is
smaller than 0,3 MPa.
7 Instruments and measurement methods
7.1 General
Measuring instruments shall meet the requirement of 7.2. As a minimum, the flow rate and
composition of the anode and cathode gases as well as the temperature, voltage, and current
of the cell/stack assembly unit shall be measured. Additional measurements shall be taken
based on the test parameters and/or test conditions. Some of the following items specified in
7.3 or 7.4 may not be measurable in the case of a cell/stack assembly unit having no anode or
cathode gas exhaust port.
7.2 Instrument uncertainty
The expanded uncertainty of each measuring instrument (coverage factor k = 2) at the time of
calibration or that estimated from the class of instrument shall meet the following
requirements:
NOTE Coverage factor is defined in ISO/IEC Guide 98-3.
Current: ±1 % relative to rated;
Voltage: ±0,5 % relative to OCV;
Temperature: ±1,0 % of reading;
Flow rates of anode and cathode gases: ±2 % of rated;
Pressures of anode and cathode gases: ±1 % of reading;average
Anode gas composition: ±2 mol % for H , H O, and N ;
2 2 2
±1 mol % for CO, CO , and CH ;
2 4
Cathode gas composition: ±0,3 mol % for O (balance N ).
2 2
7.3 Anode gas
7.3.1 Anode gas flow rate
The anode gas flow rate shall be measured using mass flow meters, volumetric flow meters or
turbine-type flow meters. The flow meter shall be selected by taking into consideration the
species in the supplied gas, the range of flow rates, and the allowable uncertainty of the flow
meter. When measurements are made on a volumetric basis, they shall be converted to mass
flow rate by measuring the gas temperature and pressure or gas density in the vicinity of the
flow meters. Measurement uncertainty for dry gases should be evaluated in accordance with
ISO 5168 or ISO 7066-2.
7.3.2 Anode gas composition
The anode gas composition should be measured when the performance of the cell/stack
assembly unit is measured. If this is not possible, however, the anode gas composition shall
be measured during the preparation of the performance test under the same conditions as
those of the cell performance test.
When anode gas is supplied in one of the following conditions a) to d) below, and if the gas
supply line has no reactors, such as a reformer, and is confirmed to insignificantly change the
gas composition, composition may be calculated based on the composition table published by
the gas supplier and values obtained from each flow meter, in accordance with ISO 6145-7:
a) a single-composition gas such as hydrogen is supplied;
b) a mixed gas of known composition is supplied;
c) anode gas is supplied by mixing component gases in a controlled manner using multiple
flow meters;
d) gases under b) and c) above are supplied in combination.
The anode gas shall be sampled near the anode gas supply port of the cell/stack assembly
unit and analysed using an infrared spectroscopy, mass spectrometer, gas chromatograph or
similar device. The gas sample shall be transported from its origin to the point of analysis in a
manner which minimizes changes in composition. Thus, the material, temperature, diameter
and the length of the tubing shall be carefully chosen to minimize the compositional change in
the sampling tubing. When necessary, it shall be heated to avoid the condensation of the
water vapour.
If water vapour is likely to affect measurement, remove water from the gas sample or dilute
the gas sample with argon or a similar inert gas.
The result of such analysis for gas component i, expressed as c (mol/m ) shall be normalized
i
to obtain a normalized concentration, x (mol /mol), using the following equation:
i
c
i
x =
(1)
i
c
i
∑
i
c
where  represents the sum of concentrations of all component gases in the analysis.
∑ i
i
The gas analyser shall be calibrated using a standard gas of known mass ratio.
The measurement uncertainty shall be evaluated in accordance
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