IEC 63202-1:2019

Photovoltaic cells - Part 1: Measurement of light-induced degradation of crystalline silicon photovoltaic cells

IEC 63202-1:2019 describes procedures for measuring the light-induced degradation (LID) of crystalline silicon photovoltaic (PV) cells in simulated sunlight. The magnitude of LID in a crystalline silicon PV cell is determined by comparing maximum output power at Standard Test Conditions (STC) before, and after, exposure to simulated sunlight at a specified temperature and irradiance.
The purpose of this document is to provide standardized PV cell LID information to help PV module manufacturers in minimizing the mismatch between cells within the same module, thereby maximizing power yield.

Cellules photovoltaïques - Partie 1: Mesure de la dégradation induite par la lumière des cellules photovoltaïques au silicium cristallin

l'IEC 63202-1:2019 décrit les procédures pour la mesure de la dégradation induite par la lumière (LID, light-induced degradation) des cellules photovoltaïques (PV) au silicium cristallin sous éclairement solaire simulé. L'amplitude de la dégradation induite par la lumière dans une cellule photovoltaïque au silicium cristallin est déterminée en comparant la puissance de sortie maximale aux conditions normales d’essai ((STC, standard test conditions) avant et après l'exposition à un éclairement solaire simulé, à une température et un éclairement spécifiés.
L'objet du présent document est de fournir des informations sur la dégradation induite par la lumière des cellules photovoltaïques normalisées, afin d'aider les fabricants de modules photovoltaïques à réduire le plus possible la désadaptation entre les cellules à l'intérieur du même module, augmentant ainsi au maximum le rendement de puissance.

General Information

• Status: Published
• Publication Date: 19-Jun-2019
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: WG 8 - TC 82/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 20-Jun-2019
• Completion Date: 31-May-2019

Overview

IEC 63202-1:2019 is an international standard published by the International Electrotechnical Commission (IEC) that specifies procedures for measuring the light-induced degradation (LID) of crystalline silicon photovoltaic (PV) cells. The standard focuses on evaluating the decrease in the maximum power output of PV cells after exposure to simulated sunlight under controlled conditions. This standardized approach enables PV module manufacturers and researchers to assess and minimize cell mismatch within modules, thereby optimizing power yield and enhancing solar panel performance.

Key Topics

• Light-Induced Degradation (LID) Measurement: IEC 63202-1 defines the method to quantify the effect of LID, which is the reduction in electrical performance of crystalline silicon PV cells caused by exposure to light. This is done by comparing the maximum power output before and after exposure to simulated sunlight under Standard Test Conditions (STC).

• Test Setup Requirements: The standard outlines the necessary apparatus, including steady-state Class BBB (or better) solar simulators, environmental chambers capable of maintaining cell temperatures around 60 ± 5 °C, and irradiance sensors compliant with IEC 60904 series requirements.

• Sample Size and Sampling: A minimum of twenty PV cells from the same sorting bin and batch are recommended to ensure statistical relevance. The standard encourages random sampling to accurately represent production quality.

• Testing Procedure: The test involves:

  • Measuring the initial I-V curves of each cell at STC, repeated three times to ensure precision.
  • Subjecting the cells to controlled light exposure until reaching a cumulative irradiance of 5 kWh/m² followed by intermittent exposures of 1 kWh/m².
  • Monitoring performance degradation until the LID magnitude stabilizes (quasi-stabilization), or until a total exposure of 20 kWh/m² is reached.
  • Regularly resting cells between measurements and potentially performing periodic electroluminescence (EL) tests to detect physical damage.

• Data Reporting and Analysis: The standard specifies comprehensive reporting of cell performance degradation, including power, current, and efficiency changes, with graphical presentation such as bar charts for clarity.

Applications

• PV Module Manufacturing: By standardizing LID measurement, IEC 63202-1 helps manufacturers minimize variations and mismatches between cells within the same module, improving overall module reliability and energy yield.

• Quality Control: Provides a reliable, repeatable test method to screen PV cells for LID behavior, supporting consistent product quality and benchmarking between different production batches or technologies.

• Research & Development: Assists in material and process optimization for crystalline silicon PV cells by enabling accurate assessment of light-induced degradation under simulated sunlight conditions.

• Performance Prediction: Enables more precise modeling of module degradation over time, contributing to better warranty estimations and lifespan forecasting for PV installations.

Related Standards

• IEC 60904 Series: Covers fundamental photovoltaic device testing methods including current-voltage (I-V) characterization (IEC 60904-1), reference device requirements (IEC 60904-2), and solar simulator performance (IEC 60904-9), which IEC 63202-1 references for test methodology and apparatus specifications.

• IEC 61215 Series: Focuses on the qualification and type approval of crystalline silicon terrestrial PV modules including LID measurements at the module level, providing context to cell-level measurements in IEC 63202-1.

• ISO/IEC Directives, Part 2: Provides guidelines on standard development and drafting practices referenced in preparing IEC 63202-1.

Summary

IEC 63202-1:2019 establishes essential standardized methods for accurately measuring the light-induced degradation of crystalline silicon photovoltaic cells under simulated sunlight. This standard is critical for PV manufacturers, laboratories, and researchers aiming to improve cell quality, reduce mismatch losses in modules, and maximize solar energy output. It complements existing photovoltaic testing standards and supports the ongoing advancement and reliability of solar energy technology globally.

Keywords: IEC 63202-1, light-induced degradation, LID measurement, crystalline silicon photovoltaic cells, solar simulator, photovoltaic testing, PV cell quality, photovoltaic standards, power output degradation, solar energy efficiency, photovoltaic module manufacturing.

Standards Content (Sample)

IEC 63202-1 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic cells –
Part 1: Measurement of light-induced degradation of crystalline silicon
photovoltaic cells
Cellules photovoltaïques –
Partie 1: Mesure de la dégradation induite par la lumière des cellules
photovoltaïques au silicium cristallin

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IEC 63202-1 ®
Edition 1.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic cells –
Part 1: Measurement of light-induced degradation of crystalline silicon

photovoltaic cells
Cellules photovoltaïques –
Partie 1: Mesure de la dégradation induite par la lumière des cellules

photovoltaïques au silicium cristallin

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-6896-4

– 2 – IEC 63202-1:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Apparatus . 6
5 Sampling . 6
6 Procedure for conditioning and evaluation . 6
7 Report . 8
Annex A (informative) Bar charts presented in the test report, showing the absolute
value of I degradation for all specimens after conditions in 6.1, 6.7 and 6.10 are met . 9
mp
Figure A.1 – I values of all test samples before and after LID tests . 9
mp
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC CELLS –
Part 1: Measurement of light-induced degradation
of crystalline silicon photovoltaic cells

FOREWORD
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International Standard IEC 63202-1 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1565/FDIS 82/1583/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 63202 series, published under the general title Photovoltaic cells,
can be found on the IEC website.

– 4 – IEC 63202-1:2019 © IEC 2019
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://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.
PHOTOVOLTAIC CELLS –
Part 1: Measurement of light-induced degradation
of crystalline silicon photovoltaic cells

1 Scope
This part of IEC 63202 describes procedures for measuring the light-induced degradation (LID)
of crystalline silicon photovoltaic (PV) cells in simulated sunlight. The magnitude of LID in a
crystalline silicon PV cell is determined by comparing maximum output power at Standard
Test Conditions (STC) before, and after, exposure to simulated sunlight at a specified
temperature and irradiance.
The purpose of this document is to provide standardized PV cell LID information to help PV
module manufacturers in minimizing the mismatch between cells within the same module,
thereby maximizing power yield.
When compared to PV module LID measurements described in the IEC 61215 series, several
extra experimental factors have been found to show significant impact on the PV cell LID test,
which were not considered by IEC 61215-2. This document provides a conditioning and
measurements procedure and parameter settings required for consistent PV cell LID
measurements.
LID magnitude is one important factor of cell quality. For cells from the same sorting bin, the
most important factor is the distribution of output power after LID.
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 60904-1, Photovoltaic devices – Part 1: Measurements of photovoltaic current-voltage
characteristics
IEC 60904-2, Photovoltaic devices – Part 2: Requirements for photovoltaic reference
devices
IEC 60904-9, Photovoltaic devices – Part 9: Solar simulator performance requirements
3 Terms and definitions
No terms and definitions are listed in this document.
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

– 6 – IEC 63202-1:2019 © IEC 2019
4 Apparatus
The following apparatus are required to perform the test procedures defined in this document:
a) Solar simulator 1: Solar simulator for I-V curve measurements in accordance with
±1 °C, and the
IEC 60904-9, with means to measure cell temperature accurately to within
means to simultaneously measure the current and voltage produced by the PV cell as
defined in IEC 60904-1.
b) An environmental chamber or a space that meets following requirements:
1) One or more irradiance sensors (meeting the requirements of IEC 60904-2) to monitor
the cumulative irradiance;
2) The means to mount test cells co-planar with the irradiance sensors;
3) The capability to control cell temperature in the range of (60 ± 5) °C during the light
exposure;
4) Relative humidity ≤ 50 %;
5) The internal air shall be free of corrosive or contaminating contents.
c) Solar simulator 2: Class BBB (or better) steady-state solar simulator in accordance with
IEC 60904-9, featuring a capability to provide irradiance of (1 000 ± 50) W/m on cells
mounted in an environmental chamber.
5 Sampling
A minimum of twenty PV cells is required for this test. Additional cells can be tested to make
up for any mechanical or handling damaged samples.
Under normal sampling criteria, test cells are randomly selected from the same sorting bin
and the same production batch. If cells are to be selected using a special sampling criterion,
the detailed sampling specification shall be included in the final report. All samples for this
test shall be assigned a unique identification number for tracking and reporting purpose.
Selected PV cells shall be stored in a sealed and dark container immediately after I-V
measurements to minimize the ambient light exposure.
6 Procedure for conditioning and evaluation
6.1 Following the procedures required in IEC 60904-1, measure the I-V curve of each cell
at STC. Each measurement shall be repeated three times. Calculate the intermittent power,
P (n=0,1,2…), as the average of the maximum power reading from the three I-V curves.
n
Between each measurement, the cell shall be rested for more than 3 s, to allow the cell
temperature to recover to its initial value. The contacting scheme for cell testing should not be
changed or disturbed during this test. The repeatability of these three readings shall be better
than 0,2 %.
6.2 Place the sampled cells in the test chamber (Clause 4b), and expose all the sampled
cells to solar simulator 2 with an irradiance of (1 000 ± 50) W/m . To compensate for spatial
non-uniformity, it is recommended to systematically rotate cells to different locations in the
chamber between exposure cycles. During light exposure, the temperature of all cells shall be
maintained within the range of (60 ± 5) °C.
6.3 After the exposure described in Step 6.2 is cumulated to 5 kWh/m , repeat Step 6.1.
To practically simplify the overall test, 5 kWh/m is recommended for the first cycle instead of
1kWh/m . This first cycle exposure may be adjusted based on cell technology or desired test
conditions.
6.4 Repeat Step 6.2 to a light exposure of 1 kWh/m , and then repeat Step 6.1.
6.5 For each sample cell, repeat Step 6.4 until it reaches the LID quasi-stabilization
condition, whereby the sample cell fulfils the following condition:
P − P
max min
<0,5%
P
average
where P , P and P are calculated from three consecutive output power
max min average
measurements P , P and P
n-2 n-1 n.
A similar formula and method are used for determining the magnitude of change of I .
mp
Where applicable, a similar formula and method can also be used for cell efficiency η and
other parameters.
When one particular test cell reaches the above mentioned LID quasi-stabilization condition,
its data for the last I-V measurements shall be properly recorded, and the cell shall be exempt
from further testing.
6.6 For samples that do not achieve quasi-stabilization, as defined in Step 6.5, repeat
Step 6.2 to a light exposure of 1 kWh/m , and the repeat Step 6.1.
6.7 A sample is exempt from further testing when either of the following conditions is met:
a) LID quasi-stabilization, as defined in Step 6.5, has been achieved, or
b) Cumulative exposure has reached 20 kWh/m .
6.8 The test terminates when all cells are exempt from further testing. All data shall be
recorded properly for the final report.
When the purpose of the test is to observe LID performance, the test may be continued
.
beyond 20 kWh/m
6.9 It is recommended to conduct the test without time delay between cycles; otherwise,
put the samples at room temperature (25 °C ± 5 °C) in a dark container, which is sealed or
with nitrogen gas purging.
6.10 Periodic electroluminescence (EL) testing of the samples is recommended to determine
whether or not cells are damaged due to repeated handling. If any damage is observed, by
either EL test or other ways, the data shall be specially marked in the final report.

– 8 – IEC 63202-1:2019 © IEC 2019
7 Report
Following completion of the procedure, a report of the test shall be prepared by the agency.
Additionally the following shall be included.
a) Description and identification of the item tested, including the specimen size, testing cells
details such as their origin and pedigree;
b) M
...