GB/T 31034-2014 English PDF (GBT31034-2014)

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GB/T 31034-2014: Insulating back sheet for crystalline silicon terrestrial photovoltaic (PV) modules
GB/T 31034-2014
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.035.99
K 15
Insulating back sheet for crystalline
silicon terrestrial photovoltaic (PV) modules
ISSUED ON. DECEMBER 05, 2014
IMPLEMENTED ON. JULY 01, 2015
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions ... 5 
4 Product classification ... 5 
5 Requirements ... 6 
6 Test methods ... 8 
7 Inspection rules ... 16 
8 Packaging, marking, transportation and storage ... 17 
Insulating back sheet for crystalline
silicon terrestrial photovoltaic (PV) modules
1 Scope
This standard specifies the classification, requirements, test methods,
inspection rules, packaging, marking, transportation and storage of insulating
back sheet for crystalline silicon terrestrial photovoltaic (PV) modules.
This standard applies to insulating back sheet for crystalline silicon terrestrial
photovoltaic (PV) modules (hereinafter referred to as “back sheet”).
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
GB/T 191-2008 Packaging - Pictorial marking for handling of goods
GB/T 1408.1-2006 Electrical strength of insulating materials - Test methods
- Part 1. Tests at power frequencies
GB/T 1410-2006 Methods of test for volume resistivity and surface resistivity
of solid electrical insulating materials
GB/T 2423.3-2006 Environmental testing for electric and electronic products
- Part 2. Testing method test Cab. Damp heat steady state
GB/T 2423.17-2008 Environmental testing for electric and electronic
products - Part 2. Test method - Test Ka. Salt mist
GB/T 2790-1995 Adhesives, 180° peel strength test method for a flexible-
bonded-to-rigid test specimen assembly
GB/T 3979-2008 Methods for the measurement of object color
GB/T 7921-2008 Uniform color space and color difference formula
GB/T 8808-1988 Soft composite plastic material - Peeling test method
GB/T 9286-1998 Paints and varnishes - Cross cut test for films
GB/T 13542.2-2009 Film for electrical insulation - Part 2. Methods of test
GB/T 16935.1-2008 Insulation coordination for equipment within low-voltage
systems - Part 1. Principles requirements and tests
GB/T 21529-2008 Determination of water vapor transmission rate for plastic
film and sheeting - Electrolytic detection sensor method
GB/T 23988-2009 Determination for abrasion resistance of coatings by
falling abrasive
GB/T 23989-2009 Determination for the solvent resistance of coatings by
solvent rubs
GB/T 26253-2010 Determination of water vapor transmission rate for
plastics-film and sheeting - Infrared detection sensor method
IEC 61215.2005 Crystalline silicon terrestrial photovoltaic (PV) modules -
Design qualification and type approval
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Water vapor transmission rate; WVTR
The amount of water vapor which transmits through unit area of the sample
per unit time under specific conditions, in grams per square meter of day [g
/ (m2 • d)].
4 Product classification
The back sheet protects and supports the crystalline silicon terrestrial
photovoltaic modules; it has reliable insulation, hydrolysis resistance, ultraviolet
resistance, electric thermal aging resistance. Generally, it has a three-layer
structure. the outer layer of fluorine film [polyvinyl fluoride (PVF), polyvinylidene
fluoride (PVDF), etc.], a fluorine coating [polytetrafluoroethylene (PTFE),
chlorotrifluoroethylene resin (CTFE), etc.] protective layer has good resistance
to environmental corrosion; the middle layer is usually polyester (PET) film,
which has good insulation performance; the inner layer is fluorine film or fluorine
coating, ethylene and polyethylene vinyl acetate (PEVA) copolymer, etc., which
has good bonding performance.
6.3 Thickness
In accordance with the provisions of clause 4 of GB/T 13542.2-2009. In the
same roll of sample, along the film roll, transversely take three strips of back
sheets of the original width and 100 mm length as the specimen, measure 9
points at each strip of specimen, wherein the spacing between any two points
shall be not less than 50 mm. For the non-edge-cut specimen, the
measurement point shall be 50 mm away from the edge. For the edge-cut
specimen, the measurement point shall be 2 mm away from the edge. Record
the data result, take the median, report the minimum value.
6.4 Thermal shrinkage rate
In accordance with the provisions of clause 23 of GB/T 13542.2-2009. Hang
the specimen in a constant temperature oven at a heating temperature of (150
± 2) °C, the heating time is 30 min. Test two specimens. Respectively use the
average values of the longitudinal and transverse shrinkage rates as test results.
6.5 Water vapor transmission rate
6.5.1 Electrolytic sensor method
In accordance with the provisions of GB/T 21529-2008. Test conditions.
Temperature (38 ± 2) °C, relative humidity (90 ± 2) %; test three specimens, the
result takes the median, report the maximum value. It is recommended to give
priority to this method.
6.5.2 Infrared sensor method
In accordance with the provisions of GB/T 26253-2010. Test three specimens,
the result takes the median, report the maximum value.
6.6 Tensile strength and elongation at break
In accordance with the provisions of clause 11 of GB/T 13542.2-2009. The
specimen has a length of 200 mm and a width of (15 ± 1) mm, take 5 specimens
along transverse and longitudinal directions, respectively. The measurement
accuracy of the specimen width is not less than 0.1 mm. At the middle of the
specimen, make two marking lines which are apart for at least 50 mm; at the
tensile speed of 100 mm /min, apply the load until the single component of the
specimen is broken, as an end point. Take the median value of the five test
values in the transverse and longitudinal directions, respectively, as the result,
report the minimum value.
6.7 Inter-layer peel strength [composite type (including fusion bonding
type)]
In accordance with the provisions of GB/T 2790-1995. The specimen has a
6.10 Back sheet/silicone peel strength
Take two 200 mm × 15 mm back sheets, spread the specified silicone evenly
on the outer surface of one back sheet specimen (contact the air surface); use
the outer surface of another back sheet to cover the silicone. There is no gap
between the two back sheets and the silicone. The silicone’s thickness is 3 mm
~ 5 mm. Under the conditions of temperature 20 °C ~ 25 °C and humidity 50%
~ 80%, dry it for 7 d. Perform test in accordance with the provisions of method
A in GB/T 8808-1988. Test five groups of specimens, take the median value,
report the minimum value.
Note. For the fusion-bonded back sheet, before the test, it may laminate and
condition the back sheet at 145 °C for 20 min.
6.11 Breakdown voltage
In accordance with the provisions of GB/T 1408.1-2006. Use an electrode
system which has an upper and lower electrode diameter of Φ6 mm. The test
is carried out in transformer oil. The electrical st...