A test method for pcr aging of solar encapsulant film

Abstract

A kind of solar encapsulant film PCT aging test method, the method includes sample preparation, heating lamination, edge sealing, aging test, drying treatment, peel strength test.The edge sealing of this method, due to the adoption of water resistance, single-sided insulation, ductility all very good aluminum foil tape, plus the gap near the transparent PET tape of the bonding place of aluminum foil tape and laminated piece, the water resistance of the prepared laminated piece sample will be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of solar encapsulation film technology, specifically a PCT aging test method for EVA films. Background Technology

[0002] Over the past decade, the photovoltaic industry has experienced rapid development. With advancements in solar cell technology, the photoelectric conversion efficiency of modules has continuously improved. Simultaneously, the lifespan of photovoltaic modules has become a significant concern. The backsheet materials and EVA encapsulation materials of photovoltaic modules are highly dependent on the environment, easily affected by temperature and humidity. Therefore, aging performance testing of these materials is an essential test for verifying their performance. Among these factors, the performance of the solar encapsulation film is one of the main factors affecting the module's lifespan.

[0003] CN201610996247.2 discloses an accelerated testing method for the anti-PID performance of a photovoltaic module encapsulation film. The method first involves encapsulating a small solar photovoltaic module with an encapsulation film. After shielding the front of the module from light, a constant current source is connected to the positive and negative terminals of the module, and a constant current is passed through the module, recording the voltage value displayed by the constant current source. Then, a conductive metal foil is attached to the glass surface of the module. Under high temperature, high humidity, and applied bias voltage conditions, the module undergoes a PID test for 1 to 96 hours. A constant current source is then passed through the module again, and the voltage value displayed by the constant current source is recorded. Finally, the voltage drop ratio is obtained.

[0004] CN202010693014.1 relates to a test method for rapidly evaluating the anti-PID effect of photovoltaic module encapsulation film, including: S1 designing the module panel; S2 stacking the modules in single-glass and double-glass structures and pressing them in a laminator; S3 calibrating the initial power of the module under test, attaching double-sided conductive copper foil around the module, placing it in an aging chamber, setting the test negative high voltage, the temperature and humidity of the aging chamber, and starting the equipment to perform anti-PID performance testing; S4 after the test, removing the module, placing it at room temperature for a period of time, calibrating the module power after the test, and the PID result is the ratio of the power difference before and after the module test to the initial power of the module; S5 determining the module power attenuation standard.

[0005] CN202210014038.9 provides a method for testing and evaluating the corrosion resistance of encapsulating films used in photovoltaic modules. The method includes the following steps: Sample preparation stage: aging a laminate containing an encapsulating film to peel off the encapsulating film from the aged sample as the test film; Testing stage: immersing the test film in a solvent to obtain the acid content in the test film, denoted as C; After peeling off the test film from the aged sample, the test film must be immersed within 30 minutes; C is used to characterize the corrosion resistance of the encapsulating film, where a larger C indicates poorer corrosion resistance.

[0006] CN202211412674.3 discloses an accelerated testing device and method for the performance of POE encapsulation film with anti-PID, including a test chamber, a protective door, a constant current power supply for temperature and humidity system and electrode fixtures. The test chamber is equipped with a placement mechanism for placing solar modules. The placement mechanism includes a base plate, which is fixedly connected to the bottom of the inner wall of the test chamber. Four sliding grooves are equally spaced on the top of the base plate, and sliders are slidably connected to the inner surface of the sliding grooves.

[0007] PCT aging test is an important test method to verify the weather resistance, moisture resistance, and adhesion and durability of components.

[0008] PCT aging tests place samples under harsh temperature, saturated humidity, and pressure environments to verify the adhesion and durability of the encapsulating adhesive. In the photovoltaic industry, PCT aging tests are a necessary performance testing item for both EVA and POE films. Currently, module manufacturers commonly use silicone rubber for edge sealing and frame bonding during production because it is convenient to use, has high bonding strength, good sealant performance, a wide range of bonding materials, good electrical insulation properties, and excellent weather resistance, making it the industry's preferred choice. In PCT testing experiments by encapsulating film manufacturers, to achieve the best possible water resistance for finished modules while being easy to operate and cost-effective, researchers have tried various methods for edge sealing, including using masking tape, PET tape, and aluminum-plastic tape after module lamination. However, these methods have relatively poor water resistance and cannot achieve the same effect as silicone rubber used in module manufacturing.

[0009] Taking PET tape as an example, the inventor's early PCT aging test sample sealing method was as follows:

[0010] 1. Sample Preparation. Take two 200mm×150mm pieces of EVA film, one 200mm×300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm×300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing board. Stack them together in the following order from bottom to top: glass, EVA film 1, EVA film 2, and backing board, and then secure them with masking tape.

[0011] 2. Heating and laminating. According to product requirements, set the vacuuming time, lamination time, lamination temperature and pressure to obtain a laminated sample with no appearance defects.

[0012] 3. Edge sealing. Use PET transparent tape to seal the four edges of the component, such as... Figure 1 As shown.

[0013] 4. Aging test. Place the sample in the PCT aging chamber and set the appropriate time, temperature and relative humidity.

[0014] 5. Let stand. Let stand in an open environment at room temperature for 2-4 hours.

[0015] 6. Inspect the appearance. Conduct a visual inspection to check the water resistance of the PET tape to the laminate and ensure that the aged laminate is free of defects.

[0016] 7. Peel strength test. The test shall be conducted in accordance with the standard GB / T 29848-2018.

[0017] The common testing method is to use transparent PET tape or masking tape for sealing. However, when these two types of tape are used alone, the weather resistance of the samples is poor under extreme testing conditions of high temperature and high humidity. Moreover, the water resistance of the tape edges is limited, and moisture can easily enter the components from the tape edges, thus affecting the test results. Summary of the Invention

[0018] To address the problem of poor water resistance at the edges of laminated components during existing PCT aging tests of EVA films, this invention provides an edge-sealing method for PCT aging tests of EVA films. This aging test edge-sealing method effectively solves the problem of poor water resistance at the edges of laminated components.

[0019] The PCT aging test sealing method provided by this invention is a sealing method that combines PET transparent tape and aluminum foil tape.

[0020] The significance of PCT aging test is as follows: In the PCT aging test of photovoltaic films, the PCT high-pressure boiling aging test is a known test method used to evaluate the durability and reliability of photovoltaic films under high temperature and high humidity environments. The PCT high-pressure boiling aging test involves placing the sample under harsh conditions of temperature, saturated water vapor (100% RH), and high pressure to verify the sample's ability to withstand high temperature and high humidity. The PCT high-pressure boiling aging test has a short testing cycle and can quickly detect the degree of failure in the material's mechanical, electrical, and optical properties.

[0021] After heat lamination, the polymer chains of the EVA film crosslink from linear chains into a network of polymer chains. With the help of silane coupling agents or tackifiers, the EVA film can improve the bonding, adhesion, and compatibility between the glass and the film through a bidirectional chemical reaction, thereby enhancing adhesive performance. The peel strength of the laminated components after accelerated aging in a PCT aging chamber is also a crucial indicator of module performance. Furthermore, the edge water-blocking effect of the laminated components is a significant factor affecting the adhesive strength after PCT aging testing; therefore, the edge sealing method for laminated components in PCT aging testing is extremely important.

[0022] To address the aforementioned technical problems, this invention provides a method for testing the PCT aging of solar encapsulation films, the method comprising the following steps:

[0023] Step (1), sample preparation: select adhesive film, glass, and backing plate, and stack them in the order of glass, adhesive film 1, adhesive film 2, and backing plate, and then fix them.

[0024] Step (2): Heat lamination at a temperature of 80-200℃ for 300-1000 seconds to obtain laminated sample.

[0025] Step (3), sealing the edges: use tape 1 to seal the edges around the perimeter, and use tape 2 to bond tape 1 to the edge of the gap in the laminate;

[0026] Step (4), aging test: place the sealed laminate sample into the PCT aging chamber at a temperature of 100-150℃ for 24-100h.

[0027] Step (5): Drying treatment, the drying temperature is 15-50℃, and the time is 0.5-10h;

[0028] Step (6), peel force test, perform peel force test.

[0029] Further, in step (1), the adhesive film 1 is a type of transparent EVA or EVT, and the adhesive film 2 is a type of transparent EVC, white EVA, white co-extruded EVA, or transparent EPE.

[0030] Further, in step (1), the film is cut to a size of 200mm × 150mm.

[0031] Further, in step (1), the glass is ultra-white patterned tempered glass with a size of 200mm × 300mm.

[0032] Further, in step (1), the back panel is a white TPC back panel with a size of 200mm × 300mm.

[0033] Further, in step (1), the back panel, glass, and adhesive film are stacked in the following order from bottom to top: glass, EVA adhesive film 1, EVA adhesive film 2, and back panel. Here, the 200mm long edges of adhesive film 1 and adhesive film 2 correspond to the 200mm long edges of the glass and back panel, as shown below. Figure 3 As shown. Then, use masking tape to secure the four corners of the laminate and the midpoint of its long side.

[0034] Further, in step (2), the lamination temperature is 90℃, 100℃, 110℃, 120℃, 150℃, 180℃, 190℃, and the lamination time is 400S, 500S, 600S, 700S, 800S, 850S, 900S, 950S.

[0035] Furthermore, in step (3), the tape 1 is an aluminum foil tape. When sealing the edges, the length of the aluminum foil tape is slightly longer than the length of the laminate to reduce moisture penetration from the four corners of the laminate.

[0036] Furthermore, in step (3), the tape 2 is a transparent PET tape to reduce moisture penetration from the gaps where the aluminum foil tape and the laminate are bonded.

[0037] Further, in step (4), PCT aging test, the temperature is 110℃, 115℃, 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 130℃, 140℃, and the time is 30h, 35h, 40h, 48h, 50h, 60h, 70h, 80h, 90h.

[0038] Further, in step (4), the PCT aging test is conducted with the aging chamber set at a temperature of 121℃±0.5℃, a relative humidity of 99%~100%, and an aging time of 48h.

[0039] Furthermore, the test method for peel strength refers to standard GB / T 29848-2018.

[0040] This invention provides a test method for PCT aging of solar encapsulation films, the method comprising the following steps:

[0041] (1) Sample preparation. Take two pieces of EVA film with a size of 200mm×150mm, one piece of clean, uncontaminated ultra-white patterned glass with a size of 200mm×300mm, and one piece of white backing plate with a size of 200mm×300mm, which has a smooth surface, is free of contamination, scratches, delamination, and bubbles. Stack them up in the following order from bottom to top: glass, EVA film 1, EVA film 2, and backing plate, and then fix them with masking tape.

[0042] (2) Heating and laminating. According to the product requirements, set the vacuuming time, lamination time, lamination temperature and pressure to obtain a laminated sample with no defects in appearance.

[0043] (3) Edge sealing. Use aluminum foil tape to seal the four edges of the component, then use transparent PET tape to bond the aluminum foil tape to the seam edges of the laminate, such as... Figure 2 As shown.

[0044] (4) Aging test. Place the sample in the PCT aging chamber and set the corresponding time, temperature and relative humidity.

[0045] (5) Let stand. Let stand in an open environment at room temperature for 2 to 4 hours.

[0046] (6) Inspect the appearance. Conduct a visual inspection to check the water resistance of the PET tape to the laminate and confirm that the aged laminate is free of defects.

[0047] (7) Peel strength test. The test shall be conducted in accordance with the standard GB / T 29848-2018.

[0048] Furthermore, in the aforementioned test method, the settling time is 2-4 hours, and it needs to be done in a well-ventilated environment with a temperature within the range of 25℃±5℃.

[0049] Furthermore, the test method for peel strength refers to standard GB / T 29848-2018.

[0050] In the PCT aging test sealing method provided by this invention, the water resistance of the laminate sample is greatly improved due to the use of aluminum foil tape with excellent water resistance, single-sided insulation and ductility, plus transparent PET tape near the gap between the aluminum foil tape and the laminate.

[0051] Compared with the prior art, the PCT aging test sealing method provided by the present invention has the following advantages:

[0052] (1) This invention provides a PCT aging test sealing method with higher water resistance. This method has higher water resistance than sealing with PET tape or aluminum foil tape alone. Photovoltaic cells require the encapsulant film to have good weather resistance and durability under high temperature and humidity conditions, as well as good adhesion between the encapsulant film and the glass and backsheet. PCT aging test can quickly evaluate the performance of the encapsulant film, thereby saving time and improving testing efficiency. The quality of the edge sealing of the laminate will greatly affect the test results.

[0053] (2) The sealing method adopted in this invention fully considers that during the testing process of EVA film or EPE film, there are corrosive chemicals such as VA, salt and additives decomposed from EVA. Using a single PET tape or aluminum foil tape may affect the adhesiveness and water resistance of the tape. The sealing method adopted in this invention can give the laminate better sealing and water resistance. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the edge sealing scheme for Comparative Example 1.

[0055] 1 is a laminate, and 2 is PET transparent tape or aluminum foil tape.

[0056] Figure 2 This is a schematic diagram of the edge sealing scheme in Example 1.

[0057] Among them, 1 is a laminate, 2 is PET transparent tape, and 3 is aluminum foil tape.

[0058] Figure 3 This is a schematic diagram of the laminated components.

[0059] Among them, 1 is the back panel, 2 is film 2, 3 is film 1, and 4 is glass. Detailed Implementation

[0060] To better understand the structure of the present invention and the functional features and advantages it can achieve, the following detailed description will be provided in conjunction with preferred embodiments of the present invention:

[0061] like Figure 3 As shown, the patterned tempered glass is at the bottom, with dimensions of 200mm × 300mm; EVA film 1 and EVA film 2 are in the middle, with dimensions of 200mm × 150mm; the upper layer is the back panel, with dimensions of 200mm × 300mm. Figure 1 and Figure 2 The aluminum foil tape used is 50mm wide, and the PET transparent tape is 24mm wide.

[0062] Comparative Example 1

[0063] Take two 200mm x 150mm pieces of EVA film, one 200mm x 300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm x 300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing sheet. Stack them in the following order from bottom to top: glass, EVA film 1, EVA film 2, and backing sheet, as shown. Figure 3 As shown, the sample is then fixed with masking tape. The prepared sample is then placed in a laminator at a lamination temperature of 140℃ for 510 seconds. After lamination, the edges are sealed with 48mm wide PET transparent tape. Figure 1 As shown. The sealed sample was placed in a PCT aging chamber, set at 121℃ for 48 hours. After aging, it was dried in an oven at 25℃ for 3 hours. Finally, the peel strength was tested according to standard GB / T 29848-2018.

[0064] Comparative Example 2

[0065] Take two 200mm x 150mm pieces of EVA film, one 200mm x 300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm x 300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing sheet. Stack them in the following order from bottom to top: glass, EVA film 1, EVA film 2, and backing sheet, as shown. Figure 3 As shown, the sample is then fixed with masking tape. The prepared sample is then placed in a laminator at a lamination temperature of 140℃ for 510 seconds. After lamination, the edges are sealed with 50mm wide aluminum foil tape. Figure 1 As shown. The sealed sample was placed in a PCT aging chamber, set at 121℃ for 48 hours. After aging, it was dried in an oven at 25℃ for 3 hours. Finally, the peel strength was tested according to standard GB / T 29848-2018.

[0066] Example 1

[0067] Take two 200mm x 150mm pieces of EVA film, one 200mm x 300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm x 300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing sheet. Stack them in the following order from bottom to top: glass, EPE film 1, EVA film 2, and backing sheet, as shown. Figure 3As shown, the sample is then fixed with masking tape. The prepared sample is then placed in a laminator at a lamination temperature of 140℃ for 510 seconds. After lamination, the edges are sealed with 50mm wide aluminum foil tape, and then 24mm wide transparent PET tape is used to bond the gap between the aluminum foil tape and the laminated part. Figure 2 As shown. The sealed sample was placed in a PCT aging chamber, set at 121℃ for 48 hours. After aging, it was dried in an oven at 25℃ for 3 hours. Finally, the peel strength was tested according to standard GB / T 29848-2018.

[0068] Example 2

[0069] Take two 200mm x 150mm pieces of EVA film, one 200mm x 300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm x 300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing sheet. Stack them in the following order from bottom to top: glass, EPE film 1, EVA film 2, and backing sheet, as shown. Figure 3 As shown, the sample is then fixed with masking tape. The prepared sample is then placed in a laminator at a lamination temperature of 145℃ for 590 seconds. After lamination, the edges are sealed with 50mm wide aluminum foil tape, and then 24mm wide transparent PET tape is used to bond the gap between the aluminum foil tape and the laminated part. Figure 2 As shown. The sealed sample was placed in a PCT aging chamber, set at 121℃ for 48 hours. After aging, it was dried in an oven at 25℃ for 3 hours. Finally, the peel strength was tested according to standard GB / T 29848-2018.

[0070] Example 3

[0071] Take two 200mm x 150mm pieces of EVA film, one 200mm x 300mm piece of smooth, clean, and uncontaminated ultra-white patterned glass, and one 200mm x 300mm piece of smooth, uncontaminated, scratch-free, delaminated, and bubble-free white backing sheet. Stack them in the following order from bottom to top: glass, EVA film 1, white co-extruded EVA film 2, and backing sheet, as shown. Figure 3 As shown, the sample is then fixed with masking tape. The prepared sample is then placed in a laminator at a lamination temperature of 140℃ for 510 seconds. After lamination, the edges are sealed with 50mm wide aluminum foil tape, and then 24mm wide transparent PET tape is used to bond the gap between the aluminum foil tape and the laminated part. Figure 2As shown. The sealed sample was placed in a PCT aging chamber, set at 121℃ for 48 hours. After aging, it was dried in an oven at 25℃ for 3 hours. Finally, the peel strength was tested according to standard GB / T 29848-2018.

[0072] Comparative Examples 1-2 adopt the following... Figure 1 The sealing method shown is illustrated in Examples 1-3, which employ the aluminum foil tape and transparent PET tape method provided by this invention. Table 1 shows the initial peel strength and peel strength data of the laminates in the examples and comparative examples after aging in the PCT aging chamber.

[0073] Table 1. Test results of specific performance parameters for Examples 1-3 and Comparative Examples 1-2.

[0074]

[0075] The test results from the above embodiments and comparative examples show that the sealing method provided by the present invention is more effective than previous PET tape or aluminum foil tape sealing methods. Comparing the peel strength data after aging of Example 1 (Method 2) and Comparative Examples 1-2 (Method 1), it can be seen that both are within the acceptable range, but the method of the present invention measures a higher peel strength, more accurately reflecting the experimental results. In particular, Examples 2-3 demonstrate that for different types of adhesive films, the sealing test method of the present invention can obtain more accurate experimental results.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. All equivalent variations and modifications made based on the content of the present invention are covered within the patent scope of the present invention.

Claims

1. A test method for PCT aging of solar encapsulation film, the method comprising the following steps: Step (1), sample preparation: select adhesive film, glass, and backing plate, and stack them in the order of glass, adhesive film 1, adhesive film 2, and backing plate, and then fix them. Step (2): Heat lamination at a temperature of 80-200℃ for 300-1000 seconds to obtain laminated sample. Step (3), sealing the edges: use tape 1 to seal the edges around the perimeter, and use tape 2 to bond tape 1 to the edge of the gap in the laminate; Step (4), aging test: place the sealed laminate sample into the PCT aging chamber at a temperature of 100-150℃ for 24-100h. Step (5): Drying treatment, the drying temperature is 15-50℃, and the time is 0.5-10h; Step (6), peel force test, perform peel force test.

2. The test method according to claim 1, characterized in that, Step (1): The adhesive film 1 is a type of transparent EVA or EVT, and the adhesive film 2 is a type of transparent EVC, white EVA, white co-extruded EVA, or transparent EPE.

3. The test method according to claim 1 or 2, characterized in that, Step (1): Cut the film to a size of 200mm × 150mm.

4. The test method according to claim 1 or 2, characterized in that, Step (1): The glass is ultra-white patterned tempered glass with a size of 200mm × 300mm.

5. The test method according to claim 1 or 2, characterized in that, Step (1): The back panel is a white TPC back panel with a size of 200mm × 300mm.

6. The test method according to claim 1 or 2, characterized in that, Step (1): Stack the back panel, glass, and adhesive film in the following order from bottom to top: glass, EVA adhesive film 1, EVA adhesive film 2, and back panel. Here, the 200mm long side of adhesive film 1 and adhesive film 2 corresponds to the 200mm long side of glass and back panel, as shown in Figure 3. Then, use masking tape to fix the four corners of the laminate and the midpoint of the long side of the laminate.

7. The test method according to claim 1 or 2, characterized in that, Step (2) The lamination temperature is 90℃, 100℃, 110℃, 120℃, 150℃, 180℃, 190℃, and the lamination time is 400S, 500S, 600S, 700S, 800S, 850S, 900S, 950S.

8. The test method according to claim 1 or 2, characterized in that, Step (3): The tape 1 is aluminum foil tape. When sealing the edges, the length of the aluminum foil tape is slightly longer than the length of the laminate to reduce moisture penetration from the four corners of the laminate.

9. The test method according to claim 1 or 2, characterized in that, Step (3): The tape 2 is a transparent PET tape to reduce moisture penetration from the gaps where the aluminum foil tape and the laminate are bonded.

10. The test method according to claim 1 or 2, characterized in that, Step (4), PCT aging test, with temperatures of 110℃, 115℃, 120℃, 121℃, 122℃, 123℃, 124℃, 125℃, 130℃, 140℃, and times of 30h, 35h, 40h, 48h, 50h, 60h, 70h, 80h, and 90h.

11. The test method according to claim 1 or 2, characterized in that, In step (4), the PCT aging test is conducted with the aging chamber set at a temperature of 121℃±0.5℃, a relative humidity of 99%~100%, and an aging time of 48h.

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