IEC TS 63202-6:2026
(Main)Photovoltaic cells - Part 6: Hot water soaking test for crystalline silicon photovoltaic cells
- Abstract
IEC TS 63202:2026 defines a hot water soaking test to determine whether crystalline silicon photovoltaic (PV) cells have metallization that is durable enough to be used in PV modules.
It is applied to crystalline silicon PV cells whose metallization is made with conductive metal pastes.
Hot water soaking test is an accelerated aging test carried out using conditions of high temperature and humidity. This test can be used to identify cells with poor metal adhesion. Such cells shed some of their metal during delivery and storage, causing visual defects and potential risk of module reliability issues.
- Status
- Published
- Publication Date
- 06-Oct-2026
- Technical Committee
- TC 82 - Solar photovoltaic energy systems
- Drafting Committee
- WG 8 - TC 82/WG 8
- Current Stage
- PPUB - Publication issued
- Start Date
- 07-Oct-2026
- Completion Date
- 09-Oct-2026
IEC TS 63202-6:2026 is an IEC Technical Specification on a hot water soaking test for crystalline silicon photovoltaic (PV) cells. It specifies a way to judge whether cell metallization made with conductive metal pastes is durable enough for use in PV modules, and it is aimed at people qualifying cells, testing them, or checking their reliability in practice.
What does IEC TS 63202-6 specify?
IEC TS 63202-6 defines an accelerated aging test that combines high temperature and humidity to reveal weak metallization adhesion on crystalline silicon PV cells. The method is intended to find cells that can shed metal during delivery or storage, which can lead to visual defects and later module reliability concerns.
The document is organized into:
- Scope, normative references, terms and definitions, apparatus, sampling, procedures, and test report
- Four normative annexes that set out the process flow, tape locations, evaluation criteria, and inspection criteria
| Annex | What it covers |
|---|---|
| Annex A | Process flow for the test procedures |
| Annex B | Location of adhesive tapes on the cell |
| Annex C | Evaluation criteria for the adhesion test |
| Annex D | Assessment and inspection criteria for bubbling, metal shedding, blackening, and yellowing |
What are the key requirements of IEC TS 63202-6?
IEC TS 63202-6 combines a pre-check, a hot water soak, a visual inspection, and a post-soak adhesion check. In practice, the test shows whether metallization stays attached after stress and whether the cell surface changes in a way that suggests poor durability.
Apparatus and materials
Clause 4 requires a controlled electric-heated water bath, level III water in accordance with ISO 3696, suitable pressure-sensitive adhesive tape, and a steel roller. The water bath must hold the test temperature at 85 °C within a narrow tolerance and keep the working zone reasonably uniform, because uneven heating can change the result from sample to sample.
Sampling and identification
Clause 5 calls for at least eight cells, with test cells and control cells assigned separate roles. The samples are taken randomly from the same batch and given unique identification numbers, so each result can be traced and reported clearly.
Procedure sequence
Clause 6 starts with a visual check of both sides of each cell for metallization defects such as uneven color, weak bonding, bulging, edge bending, or loose metal powder. This step matters because damaged samples can distort the test outcome.
The adhesion test in Clause 6.2 is performed on dry samples before soaking. Tape is applied at several areas, including busbar and finger interfaces and other sensitive locations, then rolled and removed at a controlled speed to see whether metal shreds come away with the tape. Annex C provides the evaluation criteria.
The hot water soaking step in Clause 6.3 uses samples 3 to 6 in hot water for the stated soak period. The orientation depends on whether the cell is mono-facial or bifacial, and the operator watches for continuous bubbles during soaking. Annex D explains how to judge the bubbling and other visible changes.
Clause 6.4 compares the soaked cells with the control cells and looks for metal powder shedding and color change, especially yellowing or blackening. Clause 6.5 then repeats the adhesion test on selected soaked samples to show whether the bond has weakened after exposure.
Test report
Clause 7 requires a report that identifies the laboratory, the client when relevant, the tested item, the sample set, the test dates, any deviations from the method, and photos or other evidence from the inspection and evaluation steps. This makes the result usable for qualification, audits, and follow-up decisions.
What terms does IEC TS 63202-6 use?
- Photovoltaic (PV) - Refers to cells that convert light into electrical energy.
- Metallization - The metal pattern on the cell that carries current and must stay bonded to the silicon wafer.
- Conductive metal pastes - The metal-paste material used to form the metallization on the cells covered by this test.
- Adhesion test - The tape-and-roller check used before and after soaking to see whether metal comes away from the surface.
- Hot water soaking - The accelerated aging exposure in hot water used to stress the metallization.
- Control cells - Samples kept for comparison during visual inspection after soaking.
- Visual inspection - The check for metal powder shedding, color change, bubbling, and other visible damage.
Who uses IEC TS 63202-6?
IEC TS 63202-6 is used in the solar PV industry by cell manufacturers, module makers, and test laboratories. Quality managers and reliability engineers use it when qualifying metallization processes, screening batches, investigating metal adhesion problems, or comparing incoming cells against reliability expectations. Buyers and technical auditors can also use the method to request a specific, repeatable test for crystalline silicon PV cells.
Which standards are used with IEC TS 63202-6?
- IEC 60454-2:2007 - Gives the methods of test for pressure-sensitive adhesive tapes for electrical purposes, which supports the tape and roller checks used in the adhesion test.
- IEC 60454-3 (all parts) - Gives specifications for individual adhesive-tape materials, which helps select tape that fits the method.
- ISO 3696 - Specifies water for analytical laboratory use, which IEC TS 63202-6 uses for the test water quality.
What does the IEC TS 63202-6 document contain?
IEC TS 63202-6 contains a process flow figure, a figure showing adhesive-tape locations, a figure for adhesion-test evaluation, and a table of assessment and inspection criteria. It also gives a step-by-step method for sample handling, soaking, drying, visual checking, and post-soak adhesion testing.
The document is practical rather than theoretical. It tells the reader what equipment to use, how to place samples in the bath, what to observe during soaking, what to compare after soaking, and what to include in the final report. That makes it useful for laboratory work, process qualification, and reliability screening.
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Frequently Asked Questions
IEC TS 63202-6:2026 is a technical specification published by the International Electrotechnical Commission (IEC). Its full title is "Photovoltaic cells - Part 6: Hot water soaking test for crystalline silicon photovoltaic cells". This standard covers: IEC TS 63202:2026 defines a hot water soaking test to determine whether crystalline silicon photovoltaic (PV) cells have metallization that is durable enough to be used in PV modules. It is applied to crystalline silicon PV cells whose metallization is made with conductive metal pastes. Hot water soaking test is an accelerated aging test carried out using conditions of high temperature and humidity. This test can be used to identify cells with poor metal adhesion. Such cells shed some of their metal during delivery and storage, causing visual defects and potential risk of module reliability issues.
IEC TS 63202:2026 defines a hot water soaking test to determine whether crystalline silicon photovoltaic (PV) cells have metallization that is durable enough to be used in PV modules. It is applied to crystalline silicon PV cells whose metallization is made with conductive metal pastes. Hot water soaking test is an accelerated aging test carried out using conditions of high temperature and humidity. This test can be used to identify cells with poor metal adhesion. Such cells shed some of their metal during delivery and storage, causing visual defects and potential risk of module reliability issues.
IEC TS 63202-6:2026 is classified under the following ICS (International Classification for Standards) categories: 27.160 - Solar energy engineering. The ICS classification helps identify the subject area and facilitates finding related standards.
IEC TS 63202-6:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
IEC TS 63202-6 ®
Edition 1.0 2026-10
TECHNICAL
SPECIFICATION
Photovoltaic cells -
Part 6: Hot water soaking test for crystalline silicon photovoltaic cells
ICS 27.160 ISBN 978-2-8327-1534-5
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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Apparatus . 4
4.1 Electric-heated water bath . 4
4.2 Water . 5
4.3 Tape . 5
4.4 Steel roller . 5
5 Sampling . 5
6 Procedures . 5
6.1 General . 5
6.2 Adhesion test . 6
6.3 Hot water soaking . 6
6.4 Visual inspection . 6
6.5 Post Soaking Adhesion Test . 6
7 Test report . 7
Annex A (normative) Process flow . 8
Annex B (normative) Location of adhesive tapes . 9
Annex C (normative) Evaluation criteria . 10
Annex D (normative) Assessment and inspection criteria . 11
Figure 1 – Structure diagram of an electric-heated water bath . 5
Figure A.1 – Test procedures . 8
Figure B.1 – Adhesive tape locations . 9
Figure C.1 – Adhesion test evaluation criteria . 10
Table D.1 – Phenomena assessment criteria and visual inspection criteria . 11
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Photovoltaic cells -
Part 6: Hot water soaking test for crystalline silicon photovoltaic cells
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IEC TS 63202-6 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
82/2639/DTS 82/2689/RVDTS
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 Technical Specification 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/publications.
A list of all parts in the IEC 63202 series, published under the general title Photovoltaic cells,
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.
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