SEMI International Standards
Standards New Activity Report Form (SNARF)
Date Prepared: 11/16/2023Revised (if Applicable):

Document Number: 7166
SNARF for: Revision to SEMI PV79-0818, Test Method for Exposure Durability of Photovoltaic (PV) Cells to Acetic Acid Vapor

Originating Global Technical Committee: Photovoltaic
Originating TC Chapter: China
Task Force (TF) in which work is to be carried out: Crystalline Silicon Solar Cell Task Force
Note: If a new task force is needed, also submit a task force organization form (TFOF)

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1. Rationale:
a. Describe the need or problem addressed by this activity.
(Indicate the customer, what benefits they will receive, and if possible, quantify the impact on the return on investment [ROI] if the Document is implemented.)
In crystalline silicon photovoltaic (PV) modules, metal finger corrosion of PV cells has been recognized as a major degradation induced by humidity & temperature stress in the long term. In order to evaluate the module durability the damp heat (DH) stress test has been deployed. However, current DH test requires thousands of hours to complete. To shorten test duration and enable effective mass production monitoring, Japan experts have proposed the standard “SEMI PV79 Test Method for Exposure Durability of Photovoltaic (PV) Cells to Acetic Acid Vapor”, this method can reduce the test duration down to several ten hours, saving both the time and cost. SEMI PV79 was published in August 2017, 6 years past. With the development of new technologies, this standard has some limitations. After discussion with the original author of the standard, Ph.D Tadanori Tanahashi, we decided to amend the standard.
In recent years, with the rapid development of PV technology, N-type cells are gradually rising, TOPCon and HJT production capacity and demand increase, N-type cells ushered in a broad market space. Under the background of accelerated expansion of new high-efficiency cells, the evolution of cell technology has accelerated, especially the selection of encapsulation. The acetic acid released by ethylene vinyl acetate (EVA) hydrolysis have a great effect on the corrosion of metal contact in N-type cells than traditional P-type cells, and N-type cells are also more sensitive to flux, pollution ect., especially the sensitivity of the alloy layer after soldering, which increases the long-term reliability risk of N-type modules. SEMI PV79 only proposed a general test condition of 50mmol/L at 85 ℃ for 12h, without distinguishing N-type cells from PERC cells. N-type cells are more sensitive to water and acetic acid corrosion, and the test conditions of the original standard are harsh for N type cells. If the original standard is followed, the degradation of N-type cells will exceed 50%, and the differentiation is not significant. We further supplement the original standard to distinguish N type and PERC cells , we suggest add the acetic acid corrosion standard of N-type cells: 0.05mol/L 85℃ 8h (PERC: 0.5mol/L 85℃ 15h). In addition, considering the impact of flux and other pollutions we recommend adding flux and pollutions corrosion verification program.


b. Estimate effect on industry.
2: Major effect on an industry sector - identify the relevant sector
Sector or Company Information:

c. Estimate technical difficulty of the activity.
II: Some Difficulty - Disagreements on known requirements exist but developing consensus is possible

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2. Scope:
a: Describe the technical areas to be covered or addressed by this Document development activity. For Subordinate Standards, list common concepts or criteria that the Subordinate Standard inherits from the Primary Standard, as well as differences from the Primary Standard:

1．The provisions of this standard are based on the former standard SEMI PV79 and, as a supplement and an option, cover the acetic acid corrosion standard for N type and PERC cells and the details of the test tooling.

2. The test method distinguishes the types of cell samples. The test condition of N type cell is 0.05mol/L 85℃ 8h, and the test condition of P type (PERC) cell is 0.5mol/L 85℃ 15h.

3. The air circulating fan in the original standard can uniformly maintain the acetic acid concentration in the test chamber. This standard controls the wind speed of the air circulating fan in the original standard, and the wind speed is controlled at 0.3 ±0.1 m /s.

4. We use a fixed spacing polypropylene hollow-out frame to place the PV cells, which can evenly expose cells to acetic acid vapor, and at the same time complete the test of multiple cells, improving the test efficiency and accuracy.

5. Considering the influence of flux, pollution and welding process, related simulation tests are added.



b: Expected result of activity
Major revision to an existing Standard or Safety Guideline

For a new Subordinate Standard, identify the Primary Standard here:


Modification of an existing part of Standard(s) or Safety Guideline(s) including Appendices, Complementary Files, and Supplementary Materials

For Standards, identify the Standard Subtype below:
Test Method

Miscellaneous (describe below):

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3. Projected Timetable for Completion:

a: General Milestones
a. Activity Start: 11/01/2023b. 1st Draft by: 01/01/2024
c. (Optional) Informational Ballot by: d. Letter Ballot by: 07/01/2024
e. TC Chapter Approval By:11/01/2024

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4. Liaisons with other Global Technical Committees/TC Chapters/Subcommittees/TFs:
a. List SEMI global technical committees, TC Chapters, subcommittees, or task forces in your or other Regions/Locales that should be kept informed regarding the progress of this activity. (Refer to SEMI Standards organization charts and global technical committee charters and scopes as needed.)


b. List any planned Type I Liaisons with external nonprofit organizations (e.g., SDO) that should receive Draft Documents from Standards staff for feedback during this activity and be notified when the Letter Ballot is issued (refer to Procedure Manual § 7):


c. Intercommittee Ballots:
will be issued – identify the recipient global technical committee(s):

Identify the recipient global technical committee(s):
Photovoltaic (PV) - Materials
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5. Safety Considerations:
The resulting document is expected:
NOT to be a Safety Guideline

NOTE FOR "to be a Safety Guideline": When all safety-related information is removed from the Document, the Document is NOT technically sound and complete - Refer to Section 15.1 of the Regulations for special procedures to be followed.

NOTE FOR "NOT to be a Safety Guideline": When all safety-related information is removed from the Document, the Document is still technically sound and complete.

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6. Intellectual Property Considerations:
Note: Both a: and b: below should be checked for Revision of existing Standard(s) and Safety Guideline(s).

a. For a new Standard or Safety Guideline and for any part to be modified or added in a Revision of published Standards and Safety Guidelines:


If "patented technology is intended to be included in the proposed Standard(s) or Safety Guideline(s) " is selected above, then also check one:


b. For Revision, Reapproval, Reinstatement, or Withdrawal of existing Standard(s) and Safety Guideline(s):
there is no known material patented technology necessary to use or implement the Standard(s) and Safety Guideline(s), there is previously known material patented technology necessary to use or implement the Standard(s) and Safety Guideline(s)

c. The body of the Document and any Appendices, Complementary Files, Related Information sections, or Various Materials that may or may not be a part of the Document by reference:
will incorporate Copyrighted Item, the incorporation of Copyrighted Item will NOT be required



NOTE FOR ‘the use of patented technology or the incorporation of Copyrighted Item(s) is NOT required’: If in the course of developing the Document, it is determined that the use of patented technology or Copyrighted Item(s) is necessary for the Document, the provisions of Regulations § 16 must be followed.

NOTE FOR ’will incorporate Copyrighted Item’: A copyright release letter must be obtained from the copyright owner prior to publication.

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7. Comments, Special Circumstances:
None.

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8. TC Member Review:
took place between (put dates below) before approval by the GCS, or

Member Review Start Date; 10/31/2023
Member Review End Date: 11/13/2023

NOTE FOR ‘TC Member Review’ is required by the Regulations for a period of at least two weeks
before approval of a new, or a major revision of an existing, Standard or Safety Guideline. (Refer to Regulations ¶ 8.2.1)
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9. SNARF Approval Dates:
TC Chapter or GCS11/16/2023
Recorded in TC Minutes

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10. SNARF Extension Dates:
TC Chapter Extension Granted on
Extension Expires on