Work Item
ASTM WK78477

New Practice for New Practice for Using a High-Resolution Optical Microscope and a Mini-tensile Tester for Quantifying Surface Cracking Propensity of Photovoltaic Backsheets

1. Scope

1. Scope 1.1 This practice describes basic principles and operating procedures for using a high-resolution optical microscope to monitor the initiation and propagation of surface cracking on aged photovoltaic (PV) backsheets under in-situ tensile deformation. This practice contains the procedures to conduct in-situ tensile testing using a mini-tensile tester under a laser scanning confocal microscope, and to measure the depth and density of cracks on the surface of the aged PV backsheets under tensile deformation. 1.2 Units--The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. 1.4 The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes shall not be considered as requirements of this standard.


Photovoltaic (PV) backsheet; cracking; crack density; aging; mini-tensile tester; strain; optical microscope


Polymeric backsheets play critical roles in protecting solar cells from adverse environmental conditions and providing electrical insulation safety. However, due to the susceptibility of polymeric backsheets to degradation, backsheets gradually lose their mechanical integrity during outdoor services, resulting in cracking on backsheet surface or in the bulk. Such cracking can be a precursor for the ultimate backsheet failure. To ensure long-term safe operation of PV system, it is important to develop a standard test procedure to quantify the surface cracking propensity and propagation of backsheets, which is not currently existent.

The title and scope are in draft form and are under development within this ASTM Committee.


Developed by Subcommittee: E44.09

Committee: E44

Staff Manager: Kristy Straiton

Work Item Status

Date Initiated: 10-01-2021

Technical Contact: Xiaohong Gu

Item: 000