GB/T 31034-2014 English PDF (GBT31034-2014)
GB/T 31034-2014 English PDF (GBT31034-2014)
GB/T 31034-2014: Insulating back sheet for crystalline silicon terrestrial photovoltaic (PV) modules
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
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
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
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.
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.
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 strength of the transformer oil is not less than 12 kV/mm. The specimen size is 100 mm × 100 mm, the number of specimens is 5. Use the short-time (fast) boosting method to perform test, at the boosting speed of 1000 V/s. The result takes the median value; report the minimum value.
6.12 Volume resistivity
In accordance with the provisions of GB/T 1410-2006. Use a two-electrode system which has a measuring electrode diameter of Φ25 mm and a high-
voltage electrode diameter of Φ27 mm, the electrode material may be vacuum coated, conductive rubber, oil-coated aluminum foil. The DC voltage applied to the specimen is 500 V, the electrification time is 2 min, the number of specimens is 3. Take the median value of the test values as the test result, report the minimum value.
6.13 Maximum system voltage
In accordance with the provisions of GB/T 16935.1-2008. The specimen size is 100 mm × 100 mm, the number of specimens is 10.
The electrode system uses a symmetrical electrode of Φ25 mm/Φ25 mm, its edge is rounded into an arc of radius (3.0 ± 0.2) mm in accordance with Figure 1 b) of GB/1408.1-2006 [translator note. should be GB/T 1408.1-2006].
The voltage shall rise evenly from 0 V, the partial discharge will increase gradually from low to high. When the voltage exceeds 2.5 pC suddenly, record the voltage value at this time as the initial partial discharge voltage Uinc, increase voltage continuously to 1.1 Uinc, maintain for T1 (T1 = 10 s). Then such phenomenon as delamination, blistering, or discoloration.
6.16 Alkali resistance
Cut three 100 mm × 100 mm specimens, immerse them in a closed container which is filled with potassium hydroxide solution at pH 11 ± 0.2 for 24 h, take out the specimen, use clean water to rinse it clean, check whether the specimen has such phenomenon as delamination, blistering, or discoloration.
6.17 Solvent resistance
In accordance with the provisions of the method B of GB/T 23989-2009.
Prepare two specimens, the solvent is anhydrous ethanol. Perform solvent resistant wiping against the external surface (the surface in contact with air) of the back sheet, check whether the specimen’s underlying substrate is exposed. 6.18 Boiling water treatment
Cut three 100 mm × 100 mm specimens, place them in a constant temperature boiling water bath at (98 ± 2) °C to condition them for 24 hours. After removal, use the filter paper to absorb all moisture from surface. Check and record whether the specimen is delaminated, blistered, wrinkled, discolored and sticky. At the same time, determine the inter-layer peel strength of each specimen in accordance with GB/T 2790-1995, or measure the coating adhesion of each specimen in accordance with the provisions of GB/T 9286-1998.
6.19 Constant damp heat treatment
In accordance with the provisions of GB/T 2423.3-2006. Cut three 100 mm × 100 mm specimens. Place them in a constant temperature and humidity test chamber at a temperature of (85 ± 2) °C and a relative humidity of (85 ± 5) % for treatment, the treatment time is as specified in Table 2. After the test, take out the specimen, check and record whether the specimen is delaminated, blistered, cracked and sticky. At the same time, in accordance with the provisions of GB/T 1408.1-2006, determine the breakdown voltage of each specimen, the result takes the median value, report the minimum value. In accordance with the provisions of clause 11 of GB/T 13542.2-2009, determine the elongation at break of three specimens, calculate the retention rate of elongation at break, the result takes the median value, report the minimum value. In accordance with the provisions of GB/T 3979-2008 and GB/T 7921- 2008, determine the yellow index b of the specimen, calculate the Δb. The result takes the median value, report the maximum value.
6.20 UV treatment
In accordance with the provisions of clause 10.10 of IEC 61215.2005. Cut three 100 mm × 100 mm specimens, the test temperature is (60 ± 5) °C. Apply the include all items required by this standard.
1) Identification of new product’s finalization or old product’s transfer-plant production;
2) When it is in normal production for a long time, it is carried out once a year;
3) When there are major changes in raw materials, formulations and
4) When production is restored after suspended for more than half a year; 5) When the exit-factory inspection result is significantly different from the previous type inspection;
6) When the quality supervision institute proposes the inspection
If the performance test results of the product meet the requirements of this standard, it is judged as qualified. If there is a non-conformity after inspection, the sample shall be doubled for re-inspection, and the result of the re-inspection shall prevail. If the re-inspection result is acceptable, it is determined that the batch of products is qualified; if it is still unqualified, it is determined that the batch of products is unqualified.
The purchaser shall conduct product acceptance in accordance with the
provisions of this standard, the products that have passed the inspection shall be accepted. If there is non-conformity item after inspection, the sample may be doubled for re-inspection, and the result of the re-inspection shall prevail. If there are still non-conformity items, it shall be dealt with by the supplier and the purchaser through negotiation.
8 Packaging, marking, transportation and storage
The product shall be sealed and packaged in the dark. Packaging materials such as shaft core, plastic film, baffle and carton shall be able to guarantee the use requirements. The packaging shall ensure the safe transportation of the product and be accompanied by a product certificate.