Back contact solar cell module, conductive back plate and manufacturing method thereof

Abstract

The present application discloses a back-contact solar cell assembly, a conductive backplane and a manufacturing method thereof, wherein the conductive backplane comprises a composite insulating layer, a conductive layer and a back film layer, wherein the conductive layer is located between the composite insulating layer and the back film layer, and the conductive layer is a patterned layer, wherein the composite insulating layer comprises a first adhesive layer, a sub-insulating layer and a second adhesive layer, wherein the sub-insulating layer is located between the first adhesive layer and the second adhesive layer, and the second adhesive layer is located between the sub-insulating layer and the conductive layer, and wherein the composite insulating layer is provided with a plurality of openings, wherein the openings penetrate the composite insulating layer along the thickness direction of the composite insulating layer. The cell assembly comprises a plurality of solar cells, wherein the plurality of solar cells are electrically connected through the conductive backplane, which can improve the bonding force between the conductive backplane and the solar cell, facilitates the positioning of the conductive backplane and the solar cell during the process of assembling the conductive backplane and the solar cell into an assembly, and improves the reliability of the connection between the conductive backplane and the solar cell.

Description

Technical Field

[0001] The present invention generally relates to the photovoltaic field, specifically to the solar cell field, and in particular to a back-contact solar cell assembly, a conductive back plate and a manufacturing method thereof. Background Art

[0002] At present, back-contact solar cells (such as IBC, MWT, and EWT solar cells) have received extensive attention. Since there is no main grid line on the front side, or even any electrode pattern, the positive and negative electrodes are located on the back side of the cell, which reduces the shading of the cell, thereby effectively increasing the short-circuit current of the cell and improving the energy conversion efficiency of the cell. Since the short-circuit current of back-contact solar cells is much higher than that of conventional cells, the production of back-contact solar cell components requires reducing the series resistance as much as possible to reduce the ohmic loss of the component and improve the photoelectric conversion efficiency of the component.

[0003] At present, back-contact solar cell modules have begun to study the use of conductive backplanes to achieve conductive interconnection between back-contact cells. The conductive backplane is composed of an insulating dielectric layer, a patterned conductive metal foil layer (such as a copper foil layer), an EVA (ethylene-vinyl acetate copolymer) layer, and a backplane layer. The insulating dielectric layer usually uses materials such as EPE (EVA adhesion layers bonded to both sides of aPolyester film), which is prone to product defects and reliability risks during the subsequent component processing. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a back-contact solar cell module with high reliability, a conductive backplane and a method for manufacturing the same.

[0005] In the first aspect, the conductive backplane of the present invention comprises a composite insulating layer, a conductive layer and a back film layer, the conductive layer is located between the composite insulating layer and the back film layer, the conductive layer is a patterned layer, the composite insulating layer comprises a first adhesive layer, a sub-insulating layer and a second adhesive layer, the sub-insulating layer is located between the first adhesive layer and the second adhesive layer, the second adhesive layer is located between the sub-insulating layer and the conductive layer, and the composite insulating layer is provided with a plurality of openings, and the openings penetrate the composite insulating layer along the thickness direction of the composite insulating layer.

[0006] In a second aspect, the back-contact solar cell module of the present invention includes a plurality of solar cell sheets, and the plurality of solar cell sheets are electrically connected via a conductive back plate.

[0007] In a third aspect, a method for manufacturing a conductive backplane of the present invention comprises the following steps:

[0008] Forming a plurality of openings on the polymer adhesive film to obtain a composite insulating layer, wherein the polymer adhesive film comprises a first adhesive layer, a sub-insulating layer and a second adhesive layer, and the sub-insulating layer is located between the first adhesive layer and the second adhesive layer;

[0009] The composite insulating layer, the conductive layer and the back film layer stacked in sequence are rolled to obtain a conductive back plate.

[0010] According to the technical solution provided in the embodiment of the present application, the composite insulating layer includes a first adhesive layer, a sub-insulating layer and a second adhesive layer which are arranged in sequence. The second adhesive layer is used to connect the sub-insulating layer and the conductive layer, which can improve the bonding force between the sub-insulating layer and the conductive layer. The first adhesive layer is used to connect the sub-insulating layer and the solar cell sheet, which can improve the bonding force between the conductive backplane and the solar cell sheet. This facilitates positioning of the conductive backplane and the solar cell sheet during assembly of the conductive backplane and the solar cell sheet into a component, improves the reliability of the connection between the conductive backplane and the solar cell sheet, and can solve the problem of processing and positioning in the process of assembling the existing conductive backplane into a component, and the problem of low bonding force with the cell after lamination, which poses a reliability risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0012] Figure 1 is a schematic structural diagram of a conductive backplane according to an embodiment of the present invention;

[0013] Figure 2 It is a schematic structural diagram of a composite insulating layer of a conductive backplane according to an embodiment of the present invention;

[0014] Figure 3 A schematic diagram of obtaining a composite insulating layer in a method for manufacturing a conductive backplane according to an embodiment of the present invention;

[0015] Figure 4 Schematic diagram of a method for manufacturing a conductive backplane according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0017] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] One embodiment of the present invention is, please refer to Figure 1 and 2 The conductive backplane of the present invention comprises a composite insulating layer 10, a conductive layer 20 and a back film layer 30. The conductive layer 20 is located between the composite insulating layer 10 and the back film layer 30. The conductive layer 20 is a patterned layer. The composite insulating layer 10 comprises a first adhesive layer 12, a sub-insulating layer 13 and a second adhesive layer 14. The sub-insulating layer 13 is located between the first adhesive layer 12 and the second adhesive layer 14. The second adhesive layer 14 is located between the sub-insulating layer 13 and the conductive layer 30. The composite insulating layer 10 is provided with a plurality of openings 15. The openings 15 penetrate the composite insulating layer 10 along the thickness direction of the composite insulating layer 10.

[0019] In the embodiment of the present invention, one side of the second adhesive layer is bonded and fixed to the sub-insulating layer, and the other side is used to bond and fix to the conductive layer. The second adhesive layer is used to connect and fix the composite insulating layer and the conductive layer, thereby improving the bonding force between the composite insulating layer and the conductive layer, and making the composite insulating layer and the conductive layer more reliably fixed. The first adhesive layer and the second adhesive layer are sticky at room temperature (25° C.).

[0020] One side of the first adhesive layer is bonded and fixed to the sub-insulating layer, and the other side is used to bond and fix to the solar cell panel. The first adhesive layer is used to connect and fix the conductive backplane and the solar cell panel. During subsequent stacking, since the first adhesive layer is sticky at room temperature, when the solar cell panel and the conductive backplane are stacked, the position of the conductive layer and the solar cell panel is fixed, avoiding the risk of misalignment or even short circuit between the two in the subsequent process; the first adhesive layer improves the bonding force between the conductive backplane and the solar cell panel, improves the reliability of the connection between the conductive backplane and the solar cell panel, and facilitates the positioning of the conductive backplane and the solar cell panel during the process of assembling the conductive backplane and the solar cell panel into a component.

[0021] The conductive layer can be obtained by patterning the conductive metal foil. The circuit pattern on the conductive metal foil can be formed by mechanical punching, laser punching or chemical etching, but not only. The circuit pattern on the conductive metal foil depends on the pattern of the back electrode of the back contact solar cell sheet. The circuit pattern may include various shapes and / or sizes. Laser punching can be used to form a circuit pattern from a continuous roll of conductive metal foil. The material of the conductive metal foil is any one or a combination of multiple of copper, silver, aluminum, nickel, magnesium, iron, titanium, molybdenum, and tungsten. The material of the conductive metal foil is any one or an alloy of multiple of copper, silver, aluminum, nickel, magnesium, iron, titanium, molybdenum, and tungsten.

[0022] The composite insulating layer is provided with a plurality of openings. When the conductive back plate is connected to the solar cell sheet, the electrical connector is passed through the opening, one end of the electrical connector is electrically connected to the solar cell sheet, and the other end is electrically connected to the conductive layer, so that the electrode of the solar cell sheet is electrically connected to the conductive layer, thereby realizing the series connection and parallel connection between multiple solar cells. The electrical connection of multiple solar cells is realized through the conductive back plate, and the composite insulating layer can prevent short circuits between the electrical connectors, thereby improving the reliability of the electrical connection of multiple solar cells.

[0023] The material of the sub-insulating layer is polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET) or polypropylene (PP). The sub-insulating layer can be a single layer or a multi-layer structure. The sub-insulating layer does not use EPE material, which can reduce the manufacturing cost of the sub-insulating layer.

[0024] The back film layer includes a polymer back sheet, and the material of the polymer back sheet can be TPT, TPE, KPE, KPK, KPC or KPF. The polymer back sheet can be a polymer multilayer structure composed of an insulating layer composed of an insulating material (PET or PP), an adhesive layer and / or a fluorine-containing polymer coating.

[0025] The back film layer includes a polymer backboard and an encapsulation layer. The encapsulation layer is arranged between the polymer backboard and the conductive layer. The material of the encapsulation layer can be EVA film, POE film or PVB film. The material of the polymer backboard can be TPT, TPE, KPE, KPK, KPC or KPF. The polymer backboard can be a polymer multilayer structure composed of an insulating layer composed of an insulating material (PET or PP), an adhesive layer and / or a fluorine-containing polymer coating.

[0026] Furthermore, a first release layer 11 is disposed on a side of the first adhesive layer 12 facing away from the sub-insulating layer 13 .

[0027] In the embodiment of the present invention, the first release layer effectively protects the first adhesive layer, and prevents the first adhesive layer from being contaminated before being bonded and fixed to the solar cell sheet. Of course, the first release layer needs to be removed before the conductive back sheet is fixed to the solar cell sheet. The first release layer can be bonded to the first adhesive layer, and the first release layer does not chemically react with the first adhesive layer, so as to avoid contaminating the first adhesive layer.

[0028] Furthermore, the material of the first release layer 11 is silicone oil paper, and the weight of the silicone oil paper is 30-200 g / m2.

[0029] In an embodiment of the present invention, the material of the first release layer is silicone oil paper, and the weight of the silicone oil paper is 30-200 g / m2, so that the first release layer has suitable strength for rolling and laminating processing.

[0030] Furthermore, the first release layer has a grammage of 30-45 g / m2.

[0031] In an embodiment of the present invention, the first release layer has a grammage of 30-45 g / m2, so that the first release layer has a suitable strength for rolling and laminating processing.

[0032] Furthermore, the conductive layer 20 includes a conductive metal foil 21 . The conductive metal foil 21 is made of copper or aluminum. The thickness of the conductive metal foil 21 is 20-100 microns.

[0033] In an embodiment of the present invention, the conductive layer can be obtained by patterning a conductive metal foil having a thickness of 20-100 microns. While ensuring that the thickness of the conductive layer is sufficient to provide a current path with low resistance, the thickness of the conductive layer is controlled to reduce the manufacturing cost of the conductive backplane.

[0034] Furthermore, the thickness of the conductive metal foil 21 is 30-60 micrometers.

[0035] In an embodiment of the present invention, the conductive metal foil electrically connected to the entire back-contact solar cell sheet is made of copper or aluminum. At this time, the thickness of the conductive metal foil is 30-60 microns. Under the premise of ensuring that the thickness of the conductive layer is sufficient to provide a current path with low resistance, the thickness of the conductive layer is controlled to reduce the manufacturing cost of the conductive backplane.

[0036] Furthermore, the thickness of the conductive layer 20 is 15-30 microns.

[0037] In an embodiment of the present invention, a whole back-contact solar cell sheet can also be cut into half-sheets of back-contact solar cell sheets and processed into half-sheet solar cell modules. At this time, the thickness of the conductive layer is 15-30 microns. On the premise of ensuring that the thickness of the conductive layer is sufficient to provide a current path with low resistance, the thickness of the conductive layer is controlled to reduce the manufacturing cost of the conductive backplane.

[0038] Furthermore, the material of the first adhesive layer 12 and the material of the second adhesive layer 14 are independently selected from any one of organic fluorine-modified acrylic resin, epoxy-modified acrylic resin and nanomaterial-modified acrylic resin.

[0039] In an embodiment of the present invention, the acrylic resin is modified by ultraviolet rays, and the introduced CF bond is the strongest known chemical bond with a bond energy of up to 460 kJ / mol. The fluorinated polymer has stronger chemical bonding force and structural stability than any other polymer, and has excellent weather resistance, ultraviolet resistance, and excellent dielectric and insulating properties. The nanoparticles have a small size effect and an interface effect, which can enhance the absorption of ultraviolet rays, improve the ultraviolet resistance and weather resistance of the first adhesive layer and the second adhesive layer, and improve the reliability of the conductive backplane.

[0040] Further, the thickness of the sub-insulating layer 13 is 20-200 microns, and / or,

[0041] The thickness of the composite insulating layer 10 is less than 300 microns.

[0042] In an embodiment of the present invention, the thickness of the sub-insulating layer is 20-200 microns, and / or the thickness of the composite insulating layer is less than 300 microns. The thickness of the composite insulating layer and the sub-insulating layer is reasonably set to reduce the production cost of the conductive backplane while ensuring the reliability of the conductive backplane.

[0043] Furthermore, the shape of the openings 15 is circular or square, and the number of the openings 15 is 100-50,000.

[0044] In an embodiment of the present invention, the shape of the opening is circular or square, and the number of the openings is 100-50,000. The shape and number of the openings are reasonably set so that the conductive backplane can be processed in shape and number according to different types of back-contact solar cells and electrode structures, thereby reducing the processing difficulty and avoiding excessive processing.

[0045] Furthermore, the composite insulating layer 10 includes a plurality of sub-insulating layers 13 , and a third adhesive layer is provided between adjacent sub-insulating layers 13 .

[0046] In the embodiment of the present invention, the number of sub-insulating layers can be designed according to actual conditions. A single sub-insulating layer or a multi-layer sub-insulating layer can be used. When a multi-layer sub-insulating layer is used, a third adhesive layer is provided between the sub-insulating layers to fix two adjacent sub-insulating layers. The more sub-insulating layers there are, the better the insulation performance of the composite insulating layer. Of course, the manufacturing cost of the conductive backplane must also be considered.

[0047] Furthermore, the material of the third adhesive layer is any one of organic fluorine-modified acrylic resin, epoxy-modified acrylic resin and nanomaterial-modified acrylic resin.

[0048] In an embodiment of the present invention, the acrylic resin is modified by ultraviolet rays, and the introduced CF bond is one of the strongest known chemical bonds, with a bond energy of up to 460 kJ / mol. The fluorinated polymer has stronger chemical bonding force and structural stability than any other polymer, and has excellent weather resistance, ultraviolet resistance, and excellent dielectric and insulating properties; the nanoparticles have a small size effect and an interface effect, which can enhance the absorption of ultraviolet rays, improve the ultraviolet resistance and weather resistance of the third adhesive layer, and improve the reliability of the conductive backplane.

[0049] Another embodiment of the present invention is a back-contact solar cell module, which includes a plurality of solar cell sheets, and the plurality of solar cell sheets are electrically connected via a conductive back plate.

[0050] In the embodiment of the present invention, a plurality of solar cells are connected in series or in parallel via a conductive backplane.

[0051] Another embodiment of the present invention is, with reference to Figure 1-4 , a method for manufacturing a conductive backplane, comprising the following steps:

[0052] A plurality of openings are formed on the polymer adhesive film to obtain a composite insulating layer 10, wherein the polymer adhesive film includes a first adhesive layer 12, a sub-insulating layer 13 and a second adhesive layer 14 which are sequentially arranged;

[0053] The composite insulating layer 10, the conductive layer 20 and the back film layer 30 stacked in sequence are roll-pressed to obtain a conductive back sheet.

[0054] In an embodiment of the present invention, the composite insulating layer, the conductive layer and the back film layer stacked in sequence are rolled to obtain a conductive backboard. The rolling allows the composite insulating layer, the conductive layer and the back film layer to be subjected to uniform force, thereby avoiding damage to the composite insulating layer, the conductive layer and the back film layer when they are pressed together. At the same time, the production efficiency of the conductive backboard is improved.

[0055] refer to Figure 3 The polymer film is spread out and wound by three pressure rollers. After the polymer film is spread out, a number of openings are formed on the polymer film. The openings can be processed by a laser, but not only, to obtain a composite insulating layer, and then the composite insulating layer is wound on the pressure rollers to complete the processing of the composite insulating layer.

[0056] refer to Figure 4 The composite insulating layer, the conductive layer and the back film layer are pulled, and the composite insulating layer, the conductive layer and the back film layer are rolled to obtain a conductive back sheet. Before the composite insulating layer is pulled to the two pressing rollers, the second release layer needs to be peeled off to improve the bonding force between the composite insulating layer and the conductive layer.

[0057] Furthermore, the polymer film further includes a second release layer 16, and a second adhesive layer 14 is provided between the second release layer 16 and the sub-insulating layer 13.

[0058] Before rolling the composite insulating layer 10 , the conductive layer 20 and the back film layer 30 stacked in sequence to obtain the conductive back sheet, the second release layer 16 is peeled off.

[0059] In an embodiment of the present invention, the polymer film further includes a second release layer, which is convenient for forming an opening on the polymer film. When the composite insulating layer is obtained, the polymer film is fixed, which can prevent the second adhesive layer from being contaminated during the opening of the polymer film, thereby effectively protecting the polymer film. At the same time, the second release layer is also convenient for winding and packaging the polymer film. Of course, before rolling the composite insulating layer, the conductive layer and the back film layer, the second release layer needs to be peeled off to improve the reliability of fixing the composite insulating layer, the conductive layer and the back film layer.

[0060] Furthermore, the material of the second release layer 16 is silicone oil paper, and the gram weight of the second release layer 16 is 30-200 g / m2.

[0061] In an embodiment of the present invention, the material of the second release layer is silicone oil paper, and the gram weight of the second release layer is 30-200 g / m2, so that the second release layer has suitable strength for processing the opening.

[0062] Furthermore, the second release layer has a grammage of 30-45 g / m2.

[0063] In an embodiment of the present invention, the grammage of the second release layer is 30-45 g / m 2 , so that the second release layer has suitable strength for processing the opening.

[0064] Furthermore, the roller pressing pressure is 0.1 to 1.5 MPa.

[0065] In the embodiment of the present invention, the rolling pressure is 0.1-1.5 MPa, which can reduce the possibility of damaging the conductive backsheet while ensuring the connection strength between the layers of the conductive backsheet, thereby improving the yield rate of the conductive backsheet.

[0066] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A conductive backplane, characterized in that: The composite insulating layer comprises a composite insulating layer, a conductive layer and a back film layer, wherein the conductive layer is located between the composite insulating layer and the back film layer, the conductive layer is a patterned layer, the composite insulating layer comprises a first adhesive layer, a sub-insulating layer and a second adhesive layer, the sub-insulating layer is located between the first adhesive layer and the second adhesive layer, the second adhesive layer is located between the sub-insulating layer and the conductive layer, and the composite insulating layer is provided with a plurality of openings, and the openings penetrate the composite insulating layer along the thickness direction of the composite insulating layer; The material of the first adhesive layer and the material of the second adhesive layer are independently selected from any one of organic fluorine-modified acrylic resin, epoxy-modified acrylic resin and nanomaterial-modified acrylic resin; the composite insulating layer includes multiple layers of the sub-insulating layers, and a third adhesive layer is arranged between adjacent sub-insulating layers.

2. The conductive backplane according to claim 1, characterized in that: A first release layer is disposed on a side of the first adhesive layer facing away from the sub-insulating layer.

3. The conductive backplane according to claim 2, characterized in that: The material of the first release layer is silicone oil paper, and the gram weight of the first release layer is 30-200 g / m2.

4. The conductive backplane according to claim 1, characterized in that: The conductive layer includes a conductive metal foil. The conductive metal foil is made of copper or aluminum. The thickness of the conductive metal foil is 20-100 microns.

5. The conductive backplane according to claim 1, characterized in that: The thickness of the conductive layer is 15-30 microns.

6. The conductive backplane according to claim 1, characterized in that: The thickness of the sub-insulating layer is 20-200 microns, and / or, The thickness of the composite insulating layer is less than 300 microns.

7. The conductive backplane according to claim 1, characterized in that: The shape of the openings is circular or square, and the number of the openings is 100-50,000.

8. The conductive backplane according to claim 1, characterized in that: The material of the third adhesive layer is any one of organic fluorine-modified acrylic resin, epoxy-modified acrylic resin and nanomaterial-modified acrylic resin.

9. A back contact solar cell module, characterized in that: It comprises a plurality of solar cells, and the plurality of solar cells are electrically connected via the conductive backplane according to any one of claims 1 to 8.

10. A method for manufacturing a conductive backplane, characterized in that: The following steps are involved: A plurality of openings are formed on the polymer adhesive film to obtain a composite insulating layer, wherein the polymer adhesive film comprises a first adhesive layer, a sub-insulating layer and a second adhesive layer, the sub-insulating layer is located between the first adhesive layer and the second adhesive layer; the material of the first adhesive layer and the material of the second adhesive layer are independently selected from any one of organic fluorine-modified acrylic resin, epoxy-modified acrylic resin and nano-material-modified acrylic resin; the composite insulating layer comprises a plurality of sub-insulating layers, and a third adhesive layer is provided between adjacent sub-insulating layers; The composite insulating layer, the conductive layer and the back film layer stacked in sequence are rolled to obtain a conductive back plate.

11. The method for manufacturing a conductive backplane according to claim 10, characterized in that: The polymer film further includes a second release layer, and the second release layer is located on a side of the second adhesive layer away from the sub-insulating layer; Before rolling the composite insulating layer, the conductive layer and the back film layer stacked in sequence to obtain the conductive back sheet, the method further includes peeling off the second release layer.

12. The method for manufacturing a conductive backplane according to claim 11, characterized in that: The material of the second release layer is silicone oil paper, and the gram weight of the second release layer is 30-200 g / m2.

13. The method for manufacturing a conductive backplane according to claim 12, characterized in that: The roller pressing pressure is 0.1-1.5 MPa.

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