CN102637763A - Solar cell backboard with excellent weathering resistance and preparation method thereof - Google Patents

Abstract

The invention discloses a solar battery back plate with excellent weather resistance and a preparation method thereof. The battery back plate has a five-layer structure, and the five-layer structure is sequentially from the outside to the inside: a composite film containing F, a first adhesive layer , PET film, second adhesive layer, transition layer. The invention adopts the F-containing composite film and the transition layer to replace the imported PVDF or PVF film, which greatly reduces the cost. At the same time, the F-containing composite film can resist damage such as ultraviolet radiation, which ensures the excellent weather resistance of the back sheet, and the use of a transition layer ensures the excellent bonding strength between the back sheet and the solar cell module.

Description

A kind of solar cell backboard with excellent weather resistance and preparation method thereof

technical field

The invention relates to a back plate used in a solar battery module and a preparation method thereof.

Background technique

Traditional energy sources such as coal and petroleum are still the main energy sources in today's society. However, with the daily consumption of conventional energy and the resulting global pollution and climate problems, people are turning their attention to renewable energy, and hope that renewable energy can change human energy structure to maintain human sustainable development develop. Among them, solar energy has become the focus of attention due to its unique advantages. At present, the main ways for humans to use solar energy are: light-to-heat conversion, light-to-heat conversion to electricity, and light-to-electricity conversion (ie, photovoltaic power generation). Among them, photovoltaic power generation is favored for its cleanliness and safety, and has achieved considerable development in recent years. Governments of various countries attach great importance to the development of this technology, and have launched subsidy policies to support the research, use and promotion of the solar photovoltaic industry. In recent years, the installed capacity and output of solar photovoltaics in the world have grown at a rate of about 40%. In this field, my country came from behind and became the world's largest producer of solar cell modules in 2009, and formed distinctive solar industry clusters in the Yangtze River Delta, the Bohai Rim, the Pearl River Delta, and the Midwest.

Among all kinds of solar cells at present, the technology of crystalline silicon solar cells is the most mature, so it is the most widely used. The crystalline silicon solar cell module is a multi-layer structure, which is composed of a light-transmitting layer, an adhesive layer, a battery sheet, an adhesive layer, and a back sheet, which are sequentially laminated and packaged. Among them, the light-transmitting layer is generally made of glass, and the glue layer is usually made of EVA film. The back sheet is usually a multi-layer composite material. Taking the most commonly used TPT back sheet as an example, it is composed of three independent films of polyvinyl fluoride/polyethylene terephthalate/polyvinyl fluoride bonded by glue. Junction thermoformed. The main function of the solar cell back sheet is to improve the overall mechanical strength of the solar cell panel, protect the crystalline silicon wafer, and prevent water vapor from penetrating into the sealing layer to affect the service life of the solar cell. Since solar cells have to reach a service life of 25 years, the backplane must be resistant to damage caused by any external factors such as sunlight, rain, wind, impact, and changes in temperature and humidity for such a long period of time. And protect the silicon wafer in the battery. Specifically in terms of performance, the backplane must have extremely high insulation, aging resistance, UV resistance, water vapor barrier and other properties, as well as good dimensional stability and sufficient mechanical strength. As a component related to the safety of solar cell modules, the backsheet is playing an increasingly important role in the photovoltaic industry.

Take the TPT (Tedlar/PET/Tedlar) backsheet commonly used in the market as an example. The outermost layer of the backsheet is made of Tedlar film (PVF, polyvinyl fluoride), which ensures that the backsheet has good aging resistance and UV resistance. , PET (polyethylene terephthalate) film is used in the middle to ensure that the backplane has good insulation and water vapor barrier properties. The invention whose publication number is CN201841726U is such a structure, and each layer is respectively: polyvinyl fluoride film, adhesive layer, polyethylene terephthalate film, adhesive layer, polyvinyl fluoride film. In addition, other fluorine-containing films can be used instead of Tedlar films to be laminated with PET films to form a backsheet. For example, the invention with publication number CN201387885 discloses a five-layer structure: the upper and lower surfaces are PVDF material layers, the middle layer is a PET film layer, and the above three layers are bonded by glue layers. Due to the high price and limited output of PVF and other fluorine-containing films, some solar modules have begun to use paint-based backsheets, that is, fluorine-containing resins are used to coat PET films to form fluorine-containing coatings to replace fluorine-containing films. Thereby greatly reducing the cost. For example, the patent with the domestic publication number of CN201199525 discloses a seven-layer structure: including a fluorosiloxane-formed film layer, a fluorine-based film layer, a fluorosiloxane-formed film layer, a base layer, a fluorosilicone oxide layer, and Alkylation film layer, fluorine-based film layer and fluorosiloxane film layer. The patent with the publication number CN201199524 discloses a five-layer structure: a fluorosiloxane-formed film layer, a base layer, a fluorosiloxane-formed film layer, a fluorine-based film layer, and a fluorosiloxane-formed film layer. The base layer is PET or PE. The patent with the publication number CN201527978U discloses a three-layer structure: a fluororesin film layer, a PET polyester film layer, and a fluororesin film layer. This backplane greatly reduces costs. The cost of the backplane prepared by using the fluororesin film layer is relatively low, and this kind of backplane is generally prepared by coating method. The backplane prepared by this method generally has defects such as micropores, which seriously affect the performance of the backplane.

Therefore, a new solar cell backsheet and a preparation method thereof are needed to solve the above problems.

Contents of the invention

Purpose of the invention: The purpose of the present invention is to provide a high-temperature-resistant polyimide battery separator and a preparation method thereof for the existing solar battery backplane.

Technical solution: In order to achieve the purpose of the above invention, the solar battery back sheet of the present invention can adopt the following technical solution:

A solar battery back sheet with excellent weather resistance, characterized in that: the battery back sheet has a five-layer structure, and the five-layer structure is sequentially composed of F-containing composite film, the first adhesive layer, PET film, Second adhesive layer, transition layer.

Preferably, the thickness of the F-containing composite film is 0.03-0.05mm, the thickness of the first adhesive layer is 0.016-0.025mm, the thickness of the PET film is 0.1-0.3mm, and the second adhesive layer The thickness of the transition layer is 0.016-0.025mm, and the thickness of the transition layer is 0.02-0.05mm.

Preferably, the F-containing composite film is a composite film of PVDF resin and polyacrylic acid resin, wherein the thickness of the PVDF resin is 0.005-0.015 mm.

Preferably, the glue used in the first glue layer and the second glue layer is polyurethane or acrylic glue.

Preferably, the transition layer is EVA film or PE film.

A method for preparing a solar battery back sheet with excellent weather resistance, comprising the following steps:

(1) Extrude PVDF resin and polyacrylic acid resin at a working temperature of 180-230°C by double-layer co-extrusion to prepare the F-containing composite film;

(2) Pretreating the F-containing composite film, PET film, and transition layer;

(3) Coating glue on one side of the PET film, drying it at 60-150°C, and then pressing it with the F-containing composite film;

(4) Coating glue on the surface of the other side of the PET film, drying it at 60-150° C., and then pressing it with the transition layer, thereby preparing a solar cell backsheet with excellent weather resistance.

Preferably, the pressing described in step c is performed at a temperature of 80-100°C and a pressure of 5-25Kg/cm ² , and then baked at a temperature of 50-100°C for 6-48 hours; step The pressing described in d is performed at a temperature of 80-100°C and a pressure of 5-25Kg/cm ² , and then baked at a temperature of 50-100°C for 6-48 hours;

Preferably, the pretreatment process includes surface cleaning and surface chemical treatment, and the surface chemical treatment includes surface plasma treatment or surface corona treatment;

Preferably, step c and step d are replaced.

Beneficial effect: the present invention adopts F-containing composite film and transition layer to replace imported PVDF or PVF film, which greatly reduces the cost. At the same time, the F-containing composite film can resist damage such as ultraviolet radiation, which ensures the excellent weather resistance of the back sheet, and the use of a transition layer ensures the excellent bonding strength between the back sheet and the solar cell module.

Instructions attached

FIG. 1 is a schematic structural view of a solar cell backsheet with excellent weather resistance according to the present invention.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, further illustrate the present invention, should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention, after having read the present invention, those skilled in the art will understand various aspects of the present invention Modifications in equivalent forms all fall within the scope defined by the appended claims of this application.

As shown in Figure 1, the present invention discloses a solar cell back sheet with excellent weather resistance. The battery back sheet has a five-layer structure, wherein the five-layer structure is as follows from outside to inside: F-containing composite film 1, the first adhesive layer 2. PET film 3, second glue layer 4, transition layer 5. Wherein, the thickness of the F-containing composite film 1 is 0.03-0.05mm, the thickness of the first adhesive layer 2 is 0.016-0.025mm, the thickness of the PET film 3 is 0.125-0.3mm, and the thickness of the second adhesive layer 4 is 0.016-0.025mm. 0.025mm, and the thickness of the transition layer 5 is 0.02-0.05mm. The F-containing composite film 1 is a composite film of PVDF resin 11 and polyacrylic acid resin 12, wherein the thickness of the PVDF resin 11 is 0.005-0.015mm. The glue used in the first glue layer 2 and the second glue layer 4 can be polyurethane glue or acrylic glue. The transition layer 5 can be EVA film or PE film.

The preparation method of the solar cell backboard of the present invention comprises the following steps:

a. Using double-layer co-extrusion method, PVDF resin and polyacrylic acid resin are extruded at a working temperature of 180-230°C to prepare the F-containing composite film;

B, carry out pretreatment with described F-containing composite film, PET film, transition layer;

c. Coating glue on one side of the PET film, drying it at 60-120°C, and then pressing it with the F-containing composite film;

d. Coating glue on the surface of the other side of the PET film, drying it at 60-120° C., and then pressing it with the transition layer, thereby preparing a solar battery back sheet with excellent weather resistance.

Wherein, the pressing in step c is performed at a temperature of 80-100°C and a pressure of 5-25Kg/cm ² , and then baked at a temperature of 50-100°C for 6-48 hours; Pressing is performed at a temperature of 80-100°C and a pressure of 5-25Kg/cm ² , and then baked at a temperature of 50-100°C for 6-48 hours. The pretreatment in step b includes surface cleaning and surface chemical treatment. Surface chemical treatment includes surface plasma treatment or surface corona treatment. Wherein, step c and step d can replace each other.

Specific examples are as follows:

Example 1:

1. Preparation of materials:

Prepare PVDF resin and polyacrylic resin, PET film with a thickness of 0.125mm, polyurethane glue, and EVA film with a thickness of 0.05mm.

2. Preparation of the backplate:

(1) Using a double-layer co-extrusion method, PVDF resin and polyacrylic acid resin were extruded at a working temperature of 230 ° C to prepare a F-containing composite film with a thickness of 0.03 mm. The PVDF layer thickness is 0.015mm.

(2) Pretreat the PET film; the surface energy of the film after treatment is 48 dynes.

(3) Coat the glue on the surface of the PET film with a coating thickness of 40 microns, then dry it at 60°C, and then press it with the F-containing composite film at a certain temperature and pressure; the pressure temperature is 80°C, and the pressure is 25Kg /cm ² , and baked at 50°C for 48 hours.

(4) Coat glue on the other surface of the PET film with a coating thickness of 40 microns, dry it at 60°C, and then press it with the EVA film at a certain temperature and pressure, where the temperature is 80°C and the pressure is 25Kg/cm ² , and then baked at 50°C for 48 hours. In this way, a solar battery back sheet is prepared.

3. performance testing

The thickness of the backboard is 222 microns measured by a micrometer (from which the adhesive layer is calculated to be 21 microns), and the water vapor barrier capacity is measured by the ASTM F-1249 standard, and the measurement result is 1.3g/m ² .24H; measured by the ASTM D-149 standard Withstanding voltage capability, the measurement result is 25KV; the partial discharge capability test is measured using the IEC 60664-1 standard, and the test result is 1200V; the moisture freezing test is carried out using the IEC6125 standard, and the results show that: the double 85 is used to test the weather resistance (at a temperature of 85 ° C, Under the condition of humidity 85%RH, continuous ultraviolet irradiation for 3000h), the results show that:

The sample has no yellowing or bulging by visual inspection, the interlayer peel strength is 6.8N/cm, and the yellowing index △b is 1.4 (≤2).

Example 2:

1. Preparation of materials:

Prepare PVDF resin and polyacrylic resin, PET film with a thickness of 0.3mm, polyurethane glue, and EVA film with a thickness of 0.02mm.

2. Preparation of the backplate:

(1) Extrude PVDF resin and polyacrylic acid resin at a working temperature of 200°C by double-layer co-extrusion to prepare a F-containing composite film with a thickness of 0.05mm, in which the thickness of the PVDF layer is 0.008mm;

(2) Pretreat the PET film; the surface energy of the film after treatment is 52 dynes;

(3) Coat glue on one side of the PET film with a coating thickness of 50 microns, then dry it at 120°C, and then press it with the F-containing composite film at a certain temperature and pressure, and the pressure temperature is 100°C. Pressure 15Kg/cm ² , then bake at 100°C for 6 hours;

(4) Coat the surface of the other side of the PET film with glue, the coating thickness is 50 microns, dry at 120°C, and then press it with the EVA film at a certain temperature and pressure, where the temperature is 100°C, Pressure 15Kg/cm ² , and bake at 100°C for 6 hours. In this way, a solar battery back sheet is prepared.

3. performance testing

The thickness of the backboard is 420 microns measured by a micrometer (from which the adhesive layer is calculated to be 25 microns), and the water vapor barrier capacity is measured by the ASTM F-1249 standard, and the measurement result is 1.1g/m ² .24H; measured by the ASTM D-149 standard Withstanding voltage capability, the measurement result is 28KV; using IEC 60664-1 standard to measure partial discharge capability test, the test result is 1200V; using IEC6125 standard for moisture freezing test, the results show that: use double 85 to test weather resistance (at a temperature of 85 ℃, Under the condition of humidity 85%RH, continuous ultraviolet irradiation for 3000h), the results show that the sample has no yellowing, no bulging, the interlayer peel strength is 7.4N/cm, and the yellowing index △b is 1.4 (≤2).

Example 3:

1. Preparation of materials:

Prepare PVDF resin and polyacrylic resin, PET film with a thickness of 0.2mm, polyurethane glue, and EVA film with a thickness of 0.04mm.

2. Preparation of the backplate:

(1) Using a double-layer co-extrusion method, PVDF resin and polyacrylic acid resin were extruded at a working temperature of 180°C to prepare a F-containing composite film with a thickness of 0.03 mm. The PVDF layer thickness is 0.005mm.

(2) Pretreat the PET film; the surface energy of the film after treatment is 51 dynes.

(3) Coat glue on the surface of the PET film with a coating thickness of 35 microns, then dry it at 100°C, and then press it with the F-containing composite film at a certain temperature and pressure; the pressure temperature is 100°C, and the pressure is 5Kg /cm ² , and then baked at 100°C for 24 hours.

(4) Coat the other surface of the PET film with glue, the coating thickness is 35 microns, dry at 100°C, and then press it with the EVA film at a certain temperature and pressure; the temperature range is 100°C, the pressure 5Kg/cm ² , and then baked at 100°C for 24 hours. Thus, a back sheet was prepared.

3. performance testing

The thickness of the backboard is 302 microns measured by a micrometer (from which the adhesive layer is calculated to be 16 microns), and the water vapor barrier capacity is measured by the ASTM F-1249 standard, and the measurement result is 1.4g/m ² .24H; measured by the ASTM D-149 standard Withstanding voltage capability, the measurement result is 21KV; using IEC 60664-1 standard to measure partial discharge capability test, the test result is 1300V; using IEC6125 standard for moisture freezing test, the results show that: using double 85 to test weather resistance (at a temperature of 85 ° C, Under the condition of humidity 85%RH, continuous ultraviolet irradiation for 3000h), the results show that the sample has no yellowing, no bulging, the interlayer peel strength is 7.4N/cm, and the yellowing index △b is 1.6 (≤2).

The solar battery back plate prepared by the invention adopts the F-containing composite film and the transition layer to replace the imported PVDF or PVF film, which greatly reduces the cost. At the same time, the F-containing composite film can resist damage such as ultraviolet radiation, which ensures the excellent weather resistance of the back sheet, and the use of a transition layer ensures the excellent bonding strength between the back sheet and the solar cell module.

Claims (10)

1. A solar battery back sheet with excellent weather resistance, characterized in that: the battery back sheet has a five-layer structure, and the five-layer structure is sequentially from outside to inside: F-containing composite film (1), the first glue Layer (2), PET film (3), second adhesive layer (4), transition layer (5). 2. The solar battery backsheet with excellent weather resistance as claimed in claim 1, characterized in that: the thickness of the F-containing composite film (1) is 0.03-0.05mm, and the thickness of the first adhesive layer (2) The thickness is 0.016-0.025mm, the thickness of the PET film (3) is 0.125-0.3mm, the thickness of the second adhesive layer (4) is 0.016-0.025mm, and the thickness of the transition layer (5) is 0.02 -0.05mm. 3. The solar battery backsheet with excellent weather resistance as claimed in claim 1, characterized in that: the F-containing composite film (1) is a composite film of PVDF resin (11) and polyacrylic resin (12), wherein the The thickness of the PVDF resin (11) is 0.005-0.015mm. 4. The solar cell backsheet with excellent weather resistance according to claim 1, characterized in that: the glue used in the first adhesive layer (2) and the second adhesive layer (4) is polyurethane glue or acrylic glue. 5. The solar cell backsheet with excellent weather resistance according to claim 1, characterized in that: the transition layer (5) is an EVA film or a PE film. 6. The method for preparing a solar battery back sheet with excellent weather resistance as claimed in any one of claims 1-5, characterized in that it comprises the following steps: a. Using double-layer co-extrusion method, PVDF resin and polyacrylic acid resin are extruded at a working temperature of 180-230°C to prepare the F-containing composite film; B, carry out pretreatment with described F-containing composite film, PET film, transition layer; c. Coating glue on one side of the PET film, drying it at 60-120°C, and then pressing it with the F-containing composite film; d. Coating glue on the surface of the other side of the PET film, drying it at 60-120° C., and then pressing it with the transition layer, thereby preparing a solar battery back sheet with excellent weather resistance. 7. The method for preparing a solar cell backsheet with excellent weather resistance as claimed in claim 6, characterized in that the pressing in step c is at a temperature of 80-100°C and a pressure of 5-25Kg/ ^cm2 press at a temperature of 50-100°C for 6-48 hours; the press-fit described in step d is carried out at a temperature of 80-100°C and a pressure of 5-25Kg/cm ² , and then bake at a temperature of 50-100°C for 6-48 hours. 8 . The method for preparing a solar cell backsheet with excellent weather resistance as claimed in claim 6 , wherein the pretreatment in step b includes surface cleaning and surface chemical treatment. 9 . The method for preparing a solar cell backsheet with excellent weather resistance according to claim 8 , wherein the surface chemical treatment includes surface plasma treatment or surface corona treatment. 10 . The method for preparing a solar cell backsheet with excellent weather resistance as claimed in claim 6 , wherein step c and step d are replaced. 11 .