Conductive back sheet and production method, photovoltaic module and preparation method

Abstract

The present invention provides a conductive backplane and a production method, a photovoltaic module and a preparation method, and relates to the field of photovoltaic technology. The conductive backplane includes: a connecting layer and a back film layer, and a conductive layer located between the two; the connecting layer includes: a base part and a convex part protruding from the base part; the connecting layer has a conductive area that electrically connects the back electrode of the solar cell and the conductive circuit, and an insulating area that blocks adjacent conductive areas; the conductive area and the insulating area both penetrate the connecting layer; and the conductive particles are located in the conductive area. Furthermore, the solar cell is tilted in the space formed by the base part and the convex part in the connecting layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell. The insulating base film of the convex part in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium. There is no need to apply connecting materials between the solar cells, the process is simple, and there are few hidden cracks.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a conductive backplane and a production method thereof, a photovoltaic module and a preparation method thereof. Background Art

[0002] Back-contact solar cells are widely used because they have no main grid lines on the light-facing side, which reduces shading, increases the short-circuit current of the battery, and are more beautiful.

[0003] For battery modules, reducing the gaps between individual batteries in the module can increase the power output of the battery module and make the appearance more beautiful.

[0004] However, for back-contact solar cells, since the main grid lines are all arranged on the backlight side, the process of reducing the gap between each battery in the battery assembly is complicated. Summary of the invention

[0005] The present invention provides a conductive back plate and a production method, a photovoltaic module and a preparation method, aiming to solve the problem of complex process for reducing the gap between each battery in the battery module of the existing back contact solar cell.

[0006] According to a first aspect of the present invention, a conductive backplane is provided, the conductive backplane comprising: a connection layer, a back film layer, and a conductive layer located between the connection layer and the back film layer; the conductive layer has a conductive circuit;

[0007] The connecting layer comprises: a base portion and a protruding portion protruding from the base portion;

[0008] The connecting layer has a conductive area for electrically connecting the back electrode of the solar cell and the conductive circuit, and an insulating area for blocking the adjacent conductive area; both the conductive area and the insulating area penetrate the connecting layer; the connecting layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive area.

[0009] The conductive area in the connection layer of the above-mentioned conductive backplane electrically connects the back electrode of the solar cell and the conductive circuit of the conductive layer in the conductive backplane, and the insulating effect is achieved through the insulating area in the connection layer of the conductive backplane, which can avoid short circuits between positive and negative electrodes. The insulating base film of the convex part in the connection layer melts and flows between adjacent solar cells during the subsequent lamination process to form an adhesive medium to bond each solar cell, and then there is no need to apply additional connecting materials between each solar cell, which reduces the process steps, simplifies the process, and improves production efficiency. Moreover, the melted insulating base film is filled in the gaps between adjacent solar cells or in the assembly, which can reduce the pressure on the solar cell during the lamination process, reduce hidden cracks, and improve the production yield. At the same time, the solar cell is tilted in the concave space formed by the base part and the convex part in the connection layer. The above-mentioned concave space can reduce the pressure on the solar cell during the lamination process, reduce hidden cracks, and improve the production yield. Moreover, the tilted setting is conducive to reducing the gap between each solar cell to improve the power output of the battery assembly. At the same time, the concave space formed by the base part and the convex part in the above-mentioned connecting layer has a certain positioning function, which is convenient for laying and aligning the solar cells and improves the production efficiency.

[0010] According to a second aspect of the present invention, there is provided a method for producing a conductive backplane, comprising the following steps:

[0011] A connection layer is provided; the connection layer comprises: a base portion and a protruding portion protruding from the base portion; the connection layer has a conductive region for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating region for blocking adjacent conductive regions; both the conductive region and the insulating region penetrate the connection layer; the connection layer comprises an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive region;

[0012] Providing a back film layer and a conductive layer; the conductive layer has a conductive circuit;

[0013] The connection layer, the conductive layer and the back film layer are stacked in sequence and bonded by heat pressing.

[0014] According to a third aspect of the present invention, there is provided a photovoltaic assembly, comprising a plurality of solar cells, wherein the solar cells have back electrodes, and the back electrodes of the solar cells and the conductive circuits of the conductive back sheet are electrically connected by using the conductive area in the conductive back sheet as described above;

[0015] In the packaging process of forming the assembly, the solar cell is tiltedly arranged in the concave space formed by the base part and the convex part in the connection layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell;

[0016] There is an adhesive medium between adjacent solar cells, and the adhesive medium is formed by melting and flowing of the insulating base film of the protruding part of the connecting layer during the lamination process.

[0017] According to a fourth aspect of the present invention, there is provided a method for preparing a photovoltaic module, comprising the following steps:

[0018] Providing a conductive back plate as described above;

[0019] Providing a solar cell having a back electrode;

[0020] The solar cell is obliquely laid in the concave space formed by the base part and the convex part in the connection layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connection layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell;

[0021] The stack including the component precursor is laminated to electrically connect the back electrode of the solar cell to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

[0022] The above-mentioned conductive backplane production method, photovoltaic module, and photovoltaic module preparation method have the same or similar beneficial effects as the aforementioned conductive backplane, and will not be described again here to avoid repetition.

[0023] According to a fifth aspect of the present invention, there is provided a method for preparing a photovoltaic module, comprising the following steps:

[0024] A connection layer is provided; the connection layer comprises: a base portion and a protruding portion protruding from the base portion; the connection layer has a conductive region for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating region for blocking adjacent conductive regions; both the conductive region and the insulating region penetrate the connection layer; the connection layer comprises an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive region;

[0025] Providing a backing film layer;

[0026] providing a conductive layer;

[0027] Providing a solar cell having a back electrode;

[0028] The connecting layer, the conductive layer, and the back film layer are stacked in sequence, and the solar cell is obliquely laid in the concave space formed by the base part and the raised part in the connecting layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connecting layer, and the raised surface of the raised part is opposite to the backlight surface of the solar cell;

[0029] The stack including the component precursor is laminated to electrically connect the back electrode of the solar cell to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

[0030] The photovoltaic module preparation method achieves the same or similar beneficial effects as the above-mentioned conductive backplane. At the same time, the connecting layer, conductive layer, and back film layer that constitute the conductive backplane are not specially hot-pressed and bonded. Instead, the hot-pressing and bonding of the connecting layer, conductive layer, and back film layer are completed by lamination during the process of forming the photovoltaic module, thereby reducing the hot-pressing steps, thereby reducing the production steps, improving production efficiency, reducing energy consumption, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A schematic structural diagram of a first conductive backplane in an embodiment of the present invention is shown;

[0033] Figure 2 A schematic structural diagram of a first photovoltaic stack according to an embodiment of the present invention is shown;

[0034] Figure 3 A schematic structural diagram of a conductive layer in an embodiment of the present invention is shown;

[0035] Figure 4 A schematic diagram showing the structure of another conductive layer in an embodiment of the present invention is shown;

[0036] Figure 5 A schematic structural diagram of another conductive layer in an embodiment of the present invention is shown;

[0037] Figure 6 A schematic structural diagram of a second conductive backplane in an embodiment of the present invention is shown;

[0038] Figure 7A schematic structural diagram of a third conductive backplane in an embodiment of the present invention is shown;

[0039] Figure 8 A schematic structural diagram of a fourth conductive backplane in an embodiment of the present invention is shown;

[0040] Fig. 9 A schematic structural diagram of a solar cell in an embodiment of the present invention is shown;

[0041] Fig.10 A schematic diagram showing the structure of another solar cell in an embodiment of the present invention is shown;

[0042] Fig.11 A partial structural schematic diagram of an insulating base film extrusion device in an embodiment of the present invention is shown;

[0043] Fig.12 A partial structural schematic diagram of another insulating base film extrusion device in an embodiment of the present invention is shown;

[0044] Fig.13 A schematic structural diagram of a second photovoltaic stack according to an embodiment of the present invention is shown;

[0045] Fig.14 A schematic structural diagram of a third photovoltaic stack according to an embodiment of the present invention is shown.

[0046] Description of the accompanying drawings:

[0047] 1-back film layer, 2-conductive layer, 3-connecting layer, 4-solar cell, 311-conductive area, 312-insulating area, 21-adhesive film, 22-conductive wire, 23-metal foil, 24-isolation area, 25-binding site, 41-first main grid line, 42-second main grid line, 43-first secondary grid line, 44-second secondary grid line, 51-first zone of insulating base film extrusion equipment, 52-second zone of insulating base film extrusion equipment, 5-front encapsulation adhesive film. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the embodiment of the present invention, referring to Figure 1 As shown, Figure 1The schematic diagram of the structure of the first conductive backplane in the embodiment of the present invention is shown. The conductive backplane comprises: a connection layer 3 and a back film layer 1, and a conductive layer 2 located between the connection layer 3 and the back film layer 1. The conductive layer 2 has a conductive circuit.

[0050] The back film layer 1 may be only a packaging film, or the back film layer 1 may be a combination of a packaging film and a back plate layer. In the embodiment of the present invention, no specific limitation is made to this.

[0051] The connecting layer includes: a base portion and a convex portion protruding from the base portion. Figure 1 As shown, the flat area in the connecting layer 3 can be the base part, and the part protruding from the base part can be the convex part. The components of the convex part can be the same as or different from the components of the base part. The convex part and the base part can be integrally formed or formed in steps. In the embodiment of the present invention, this is not specifically limited.

[0052] The connection layer 3 has a conductive area 311 for electrically connecting the back electrode of the solar cell to the conductive circuit, and an insulating area 312 for blocking adjacent conductive areas 311. Both the conductive area 311 and the insulating area 312 penetrate the connection layer 3, that is, the conductive area and the insulating area located in the base part penetrate the base part, and the conductive area and the insulating area located in the convex part penetrate the convex part. The widths of the various conductive areas 311 can be equal or different, and the widths of the various insulating areas 312 can also be equal or different. In the embodiment of the present invention, there is no specific limitation on this. Figure 1 As shown, the height of the conductive area 311 and the insulating area 312 located in the base part is equal to the height of the base part. The height of the conductive area 311 and the insulating area 312 located in the convex part is equal to the height of the corresponding convex part. The connecting layer includes an insulating base film and conductive particles dispersed in the insulating base film, that is, the base part and the convex part both include an insulating base film and conductive particles dispersed in the insulating base film. The conductive particles are located in the conductive area 311. That is, the conductive area 311 is composed of an insulating base film and conductive particles dispersed in the insulating base film. The insulating area 312 is composed of an insulating base film. The number of conductive particles included in each conductive area 311 is not specifically limited, so that the area can be flexibly set for the purpose of conduction. The sizes of each conductive area 311 can be the same.

[0053] The solar cell may be a back contact solar cell, and a plurality of back electrodes are arranged in parallel on the back of the solar cell. The back electrodes may be main grid lines. Figure 2 As shown, Figure 2The schematic diagram of the structure of the first photovoltaic stack in the embodiment of the present invention is shown. The photovoltaic stack forms a photovoltaic module after lamination. The conductive area 311 in the connecting layer 3 is used to electrically connect the back electrode of the solar cell 4 and the conductive circuit of the conductive layer 2 in the conductive backplane. The conductive area 311 in the connecting layer 3 in the conductive backplane realizes the electrical connection between the solar cell 4 and the conductive circuit of the conductive layer 2, and the insulating area in the connecting layer 3 of the conductive backplane realizes the insulation effect, that is to say, only one layer of the connecting layer 3 in the conductive backplane realizes the electrical connection and insulation at the same time, and the process is simple. At the same time, there are no openings, which will not damage the integrity of the connecting layer 3, and thus the conductive backplane is stable and reliable. The conductive area 311 in the connecting layer 3 of the above-mentioned conductive backplane electrically connects the back electrode of the solar cell 4 and the conductive circuit of the conductive layer 2 in the conductive backplane, and the insulating area in the connecting layer 3 of the conductive backplane realizes the insulation effect, which can avoid the short circuit between the positive and negative electrodes. The insulating base film of the raised part in the connecting layer 3 melts during the subsequent lamination process and flows between the adjacent solar cells 4 to form an adhesive medium to bond the individual solar cells 4. There is no need to apply additional connecting materials between the individual solar cells 4, which reduces the process steps, simplifies the process, and improves production efficiency. At the same time, the individual solar cells are usually overlapped, and the light-facing surface of one solar cell overlaps the backlight surface of another solar cell. Since the light-facing surface of the solar cell has no electrode, even if a small amount of conductive particles in the raised part moves between adjacent solar cells due to the melting of the insulating base film, it will not cause a short circuit or leakage. Moreover, the melted insulating base film is filled in the gaps between adjacent solar cells 4 or in the assembly, which can reduce the pressure on the solar cell 4 during the lamination process, reduce hidden cracks, and improve production yield.

[0054] Reference Figure 2 As shown, the solar cell 4 is tiltedly arranged in the concave space formed by the base part and the convex part in the connecting layer 3, the convex surface of the convex part is opposite to the backlight surface of the solar cell 4, and the tilt angle is specifically determined according to the height of the convex part, the length of the solar cell, etc., and is not specifically limited in the embodiment of the present invention. The tilted arrangement is conducive to reducing the gap between each solar cell 4 to improve the power output of the battery assembly. At the same time, the solar cell 4 is tiltedly arranged in the concave space formed by the base part and the convex part in the connecting layer 3. The above-mentioned concave space can reduce the pressure on the solar cell during the lamination process, reduce hidden cracks, and improve the production yield. At the same time, the concave space formed by the base part and the convex part in the above-mentioned connecting layer 3 has a certain positioning function. The forward laying or reverse laying is convenient for the laying and alignment of the solar cell 4, thereby improving the production efficiency.

[0055] Optionally, the protrusions are periodically distributed in the connection layer, and the process is simple. For example, refer to Figure 1 As shown, the protrusions are periodically distributed on the connection layer 3 .

[0056] Optional, see Figure 3 As shown, Figure 3 A schematic structural diagram of a conductive layer in an embodiment of the present invention is shown. Figure 3 The conductive layer shown is a plurality of conductive wires 22 disposed on the adhesive film 21. The conductive wires 22 may be round solder strips or flat solder strips commonly used in the industry. The conductive wires 22 may also include an intermediate layer and a coating coated on the intermediate layer. The material of the intermediate layer may include at least one of copper, gold, silver, and aluminum. The coating may be a solder containing tin.

[0057] Reference Figure 4 As shown, Figure 4 A schematic structural diagram of another conductive layer in an embodiment of the present invention is shown. Figure 4 The conductive layer shown is a patterned metal foil. Figure 4 23 is a metal foil, and 24 is a patterned isolation area. The width of the isolation area 24 is not specifically limited. Patterning methods include mechanical punching, laser punching or chemical etching. The pattern depends on the pattern of the backlight electrode of the solar cell, and the pattern may include a variety of shapes and / or sizes. The metal foil can be copper foil or aluminum foil or any other suitable metal or metal alloy. The thickness of the metal foil can provide a current path with low resistance. If the metal foil is selected from copper foil or aluminum foil, the thickness can be 20-100um, or 30-60um.

[0058] Reference Figure 5 As shown, Figure 5 A schematic structural diagram of another conductive layer in an embodiment of the present invention is shown. Figure 5 The conductive layer shown is a patterned metal foil. Figure 5 In the embodiment, the metal foil 23 is also provided with bonding sites 25 corresponding to each conductive area in the connection layer, so as to facilitate accurate alignment of the connection layer and the conductive layer.

[0059] Optional, see Figure 2 As shown, in the direction parallel to the back film layer 1, the distance between the centers of two adjacent protruding portions is less than or equal to the length of a solar cell 4, thereby facilitating the tilted placement of the solar cell 4.

[0060] Optional, see Figure 1As shown, the height d of the protruding part protruding from the above-mentioned base part is 20-200um. The insulating base film of the protruding part in this thickness range can flow after melting during the subsequent lamination or heating process to form an adhesive medium that fully fills the adjacent solar cells 4 to bond each solar cell 4. Moreover, the melted insulating base film can fully fill the gaps between adjacent solar cells 4 or in the assembly, which can reduce the tilt angle of the solar cell 4 during the lamination process, and is more conducive to reducing the gap between each solar cell 4 to improve the power output of the battery assembly. It can further reduce hidden cracks and improve production yield.

[0061] Optionally, in the direction of setting the connection layer and the back film layer, the cross-sectional shape of the raised portion includes: a triangle, a rectangle, an arc, and a wave. Thus, the raised portion has various forms. For example, referring to Figure 1 , the cross-section of the raised part is a triangle. Figure 6 As shown, Figure 6 FIG. 2 shows a schematic diagram of the structure of a second conductive backplane in an embodiment of the present invention. Figure 6 As shown, the cross-section of the raised portion is rectangular.

[0062] Optionally, the width of the conductive area is less than or equal to the width of the back electrode to be electrically connected, so that even if the conductive area has a certain deformation during heating or hot pressing, it will not cause a short circuit and the insulation effect is good.

[0063] Optionally, the number of conductive areas in each convex portion is greater than or equal to 1, and thus a solar cell can be obliquely laid in the concave space corresponding to the base portion and the convex portion in each convex portion. Figure 1 In the conductive backplane shown, the number of conductive areas 311 in each protruding portion is 3. For another example, Figure 6 As shown, the number of the conductive areas 311 in each protruding portion is 2. For another example, Figure 7 A schematic structural diagram of a third conductive backplane in an embodiment of the present invention is shown. Figure 7 In the arrangement direction of the connection layer 3 and the back film layer 1, the cross-section of the raised portion is a triangle. Figure 7 In the conductive backplane shown, the number of conductive areas 311 in each protruding portion is 1, and the number of conductive areas 311 in the base portion between adjacent protruding portions is 1. For another example, Figure 8 A schematic structural diagram of a fourth conductive backplane in an embodiment of the present invention is shown. Figure 8 In the embodiment, in the arrangement direction of the connection layer 3 and the back film layer 1, the cross-section of the raised portion is in the shape of a rectangle. Figure 8In the conductive backplane shown, the number of the conductive regions 311 in each protruding portion is 1, and the number of the conductive regions 311 in the base portion between adjacent protruding portions is 1.

[0064] When the number of conductive regions in the raised portion is equal to 1, the width of each conductive region is less than or equal to half the width of the raised portion, and the raised portion can also be provided with an insulating region to avoid short circuit. It should be noted that if the number of conductive regions in the raised portion is equal to 1, the back electrode of the solar cell electrically connected thereto can be as follows: Fig. 9 As shown, Fig. 9 A schematic structural diagram of a solar cell in an embodiment of the present invention is shown. Fig. 9 It can be a bottom view viewed from the backlight side of the solar cell toward the light side. Fig. 9 The first main grid line 41 and the second main grid line 42 are respectively arranged at the two ends of the battery, wherein the first main grid line 41 and the second main grid line 42 have opposite polarities. The first sub-grid line 43 is connected to the first main grid line 41, and the second sub-grid line 44 is connected to the second main grid line 42. For example, if the first main grid line 41 is a positive main grid line, the second main grid line 42 is a negative main grid line, the first sub-grid line 43 is a positive sub-grid line, and the second sub-grid line 44 is a negative sub-grid line. The positive and negative main grid lines are respectively arranged at the two ends of the battery, so that the battery can be used. Figure 7 or Figure 8 The conductive area 311 in each raised portion of the conductive back plate and the conductive area 311 in the adjacent base portion are conductively connected to the corresponding busbar. The two conductive areas 311 located in two adjacent raised portions are used to connect the positive busbar of one of the two adjacent batteries and the negative busbar of the other battery.

[0065] If the number of conductive regions in the raised portion is greater than 1, the back electrode of the solar cell to which it is electrically connected may be as follows: Fig.10 As shown, Fig.10 A schematic structural diagram of another solar cell in an embodiment of the present invention is shown. Fig.10 It can be a bottom view viewed from the backlight side of the solar cell toward the light side. Fig.10 The first main grid line 41 and the second main grid line 42 are arranged in parallel and alternately, wherein the first main grid line 41 and the second main grid line 42 have opposite polarities. The first sub-grid line 43 is connected to the first main grid line 41, and the second sub-grid line 44 is connected to the second main grid line 42. For example, if the first main grid line 41 is a positive main grid line, the second main grid line 42 is a negative main grid line, the first sub-grid line 43 is a positive sub-grid line, and the second sub-grid line 44 is a negative sub-grid line. Fig.10 The solar cells shown can be used Figure 1 or Figure 6The conductive area 311 in each raised portion of the conductive backplane is conductively connected to the conductive area 311 of the adjacent base portion and the corresponding main grid line.

[0066] Optionally, the conductive particles are deformable during the process of heating and / or pressure. On the one hand, the conductive particles will not be crushed during the process of heating and / or pressure, and will not affect the conductive effect between the back electrode, the conductive area, and the conductive layer. On the other hand, the lateral area of ​​each conductive particle in the conductive area increases during the process of pressure and / or heating, and the contact area with the back electrode and the conductive layer increases, which is beneficial to enhance the conductive effect in the vertical direction.

[0067] Optionally, the conductive area is in the shape of a continuous strip or a discontinuous dot. The conductive area in the above shape enables good conductivity between the back electrode, the conductive area and the conductive layer of the solar cell.

[0068] Optionally, after being heated and / or pressed, the series resistivity of the connecting layer and the conductive layer in the vertical direction is less than or equal to 1Ω·cm 2 Furthermore, after being heated and / or pressed, the back electrode, the conductive area, and the conductive layer of the solar cell have good conductive effects.

[0069] Optionally, the material of the conductive particles is selected from at least one of: silver particles, copper particles, aluminum particles, indium alloy particles, tin alloy particles, silver-coated copper particles, graphene particles, graphene oxide particles, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) particles, and silver-coated thermoplastic polymer particles. The conductive particles of the above materials have good deformability and good conductivity during heating and / or pressure. The thermoplastic polymer particles may be PMMA (polymethylmethacrylate). The poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) particles may be / PEDOT:PSS gel.

[0070] Optionally, the conductive particles are in at least one of a spherical, quasi-spherical, and irregular shape, and the conductive particles in the above shapes have good conductive effects.

[0071] Optionally, the average particle size of the conductive particles is 0.1-100um. Since the conductive particles are only distributed in the corresponding area where the connecting layer is connected to the back electrode of the solar cell, they are conductive only in the vertical direction in the direction relative to the conductive layer of the conductive backplane of the battery back electrode after lamination. In the horizontal direction, due to the blocking effect of the insulating area in the connecting layer between adjacent electrodes, even if the conductive particles in the conductive area may expand due to deformation, they cannot directly contact the conductive particles in the adjacent opposite electrical area due to the size limitation, and will not cause defects such as short circuits. In addition, the conductive particles of the above size have good conductivity.

[0072] It can be understood that the thickness of the connecting layer needs to be greater than the particle size of the conductive particles, and the thickness of the connecting layer and the average particle size of the conductive particles need to be coordinated with each other.

[0073] Optionally, the insulating region in the connection layer may be an insulating base film, and the insulating base film in the conductive region of the connection layer and the insulating base film in the insulating region may be made of at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (POE), polyvinyl butyral (PVB) or silica gel, and the insulating base film has good insulating properties. The material of the insulating base film in the insulating region may be the same as or different from the material of the insulating base film in the conductive region, and the embodiment of the present invention does not specifically limit this.

[0074] The back film layer may be a packaging film layer or a combination of a packaging film layer and a backplane layer. The packaging film layer may be composed of one or more resins including epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (POE), polyvinyl butyral (PVB) or silica gel. The polymer backplane may use TPT, TPE, KPE, KPK, KPC or KPF. Alternatively, the polymer backplane may include a polymer multilayer structure composed of several layers of insulating material (such as PET or PP) and an adhesive layer, and the thickness and cost can be greatly reduced, and the electrical insulation is excellent and the weather resistance can also be guaranteed. The embodiment of the present invention does not specifically limit this.

[0075] The present application also provides a method for producing a conductive backplane, which specifically comprises the following steps:

[0076] Step S1, providing a connection layer; the connection layer includes: a base portion and a protruding portion protruding from the base portion; the connection layer has a conductive area for electrically connecting the back electrode of the solar cell and the conductive circuit, and an insulating area for blocking the adjacent conductive area; the conductive area and the insulating area both penetrate the connection layer; the connection layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive area.

[0077] Step S2, providing a back film layer and a conductive layer; the conductive layer has a conductive circuit.

[0078] Step S3, stacking the connection layer, the conductive layer, and the back film layer in sequence, and hot pressing and bonding them.

[0079] It should be noted that the hot pressing bonding in step S3 can be a lamination process for forming a photovoltaic module, or a special hot pressing bonding before forming a photovoltaic module, or a hot pressing bonding before forming a photovoltaic module and a secondary hot pressing of lamination in the process of forming a photovoltaic module. In the embodiments of the present invention, this is not specifically limited.

[0080] For example, the connection layer, the conductive layer, and the back film layer are stacked in sequence and initially heated, so that the conductive particles in a conductive area in the connection layer are initially deformed and form a local contact with the adjacent conductive particles in the conductive area. The local contact does not guarantee a good electrical connection. Subsequently, the manufactured conductive back sheet is stacked with the solar cell, the encapsulation film, and the cover plate and then sent to a laminator for pressing to form a photovoltaic module. The laminator pressing can be a secondary hot pressing bonding, which can further deform the conductive particles in a conductive area in the connection layer to increase the contact with the adjacent conductive particles in the conductive area and the adjacent surface, forming a good current path.

[0081] Optionally, in step S3, the hot pressing temperature is 60-120° C., the pressure is 0.01-0.2 MPa, and the hot pressing time is 1-30 min.

[0082] Optionally, the step S1 of providing the connection layer includes: forming the connection layer by extruding, casting and cooling the insulating base film precursor particles and the mixture of the insulating base film precursor particles and the conductive particles.

[0083] Specifically, refer to Fig.11 As shown, Fig.11 A partial structural schematic diagram of an insulating base film extrusion device in an embodiment of the present invention is shown. The insulating base film extrusion device can be divided into a first zone 51 and a second zone 52. The first zone 51 and the second zone 52 are alternately distributed. The first zone 51 is filled with insulating base film precursor particles, and the insulating base film precursor particles in the first zone 51 are extruded, cast, and cooled to form an insulating zone of a connecting layer. The second zone 52 is filled with insulating base film precursor particles, and conductive particles are added to the insulating base film precursor particles in the second zone 52. The insulating base film precursor particles added with conductive particles in the second zone 52 are extruded, cast, and cooled to form a conductive zone of a connecting layer. It should be noted that the first zone 51 and the second zone 52 can be extruded, cast, and cooled at the same time to form a connecting layer. Fig.11 The shape of the raised portion in the connecting layer obtained by the insulating base film extrusion equipment shown may be a triangle.

[0084] Reference Fig.12 As shown, Fig.12A partial structural schematic diagram of another insulating base film extrusion device in an embodiment of the present invention is shown. The insulating base film extrusion device can also be divided into a first zone 51 and a second zone 52. The first zone 51 and the second zone 52 are alternately distributed. The first zone 51 is filled with insulating base film precursor particles, and the insulating base film precursor particles in the first zone 51 are extruded, cast, and cooled to form an insulating zone of the connecting layer. The second zone 52 is filled with insulating base film precursor particles, and conductive particles are added to the insulating base film precursor particles in the second zone 52. The insulating base film precursor particles added with conductive particles in the second zone 52 are extruded, cast, and cooled to form a conductive zone of the connecting layer. It should be noted that the first zone 51 and the second zone 52 can be extruded, cast, and cooled at the same time to form a connecting layer. Fig.12 The shape of the raised portion in the connecting layer obtained by the insulating base film extrusion apparatus shown may be rectangular.

[0085] It should be noted that the insulating base film precursor particles may also include: at least one of a curing agent, an inorganic filler, a crosslinking agent, an initiator, and a coupling agent. The curing agent may include at least one of silane-terminated mercaptan, diisopropylbenzene peroxide, diisopropylbenzene hydroperoxide, or benzoyl peroxide. The inorganic filler may be at least one of titanium dioxide, barium sulfate, calcium carbonate, or carbon black. The initiator may be at least one of diisopropylbenzene peroxide, diisopropylbenzene hydroperoxide, or benzoyl peroxide. The coupling agent may be a silane coupling agent or a titanate coupling agent.

[0086] Optionally, in the connection layer, the base part and the protrusion part are integrally formed, thereby improving production efficiency. Alternatively, in the connection layer, the base part and the protrusion part are separately formed, which is not specifically limited in the embodiment of the present invention.

[0087] The embodiment of the present invention further provides a photovoltaic module, such as Figure 2 The photovoltaic stack shown in the figure forms a photovoltaic module after lamination. The photovoltaic module includes a plurality of solar cells 4, each of which has a back electrode, and the conductive area 311 in any of the aforementioned conductive back sheets is used to electrically connect the back electrode of the solar cell 4 and the conductive circuit of the conductive layer 2 of the conductive back sheet. In the packaging process of forming the module, the solar cell 4 is tilted in the concave space formed by the base part and the raised part in the connecting layer, and the raised surface of the raised part of the connecting layer is opposite to the backlight surface of the solar cell 4. There is an adhesive medium between adjacent solar cells 4, and the adhesive medium is formed by melting and flowing the insulating base film of the raised part in the connecting layer during the lamination process.

[0088] For example, refer to Fig.13 As shown, Fig.13 The second photovoltaic stack structure schematic diagram of the embodiment of the present invention is shown. The photovoltaic stack is laminated to form a photovoltaic module. Fig.14 As shown, Fig.14 A schematic structural diagram of a third photovoltaic stack according to an embodiment of the present invention is shown. Fig.14 After the photovoltaic stack is laminated, the overlapping area of ​​each solar cell in the photovoltaic module may be larger. The photovoltaic stack is laminated to form a photovoltaic module. For the photovoltaic stack and the laminated photovoltaic module, please refer to the above-mentioned relevant records, and in order to avoid repetition, it will not be repeated here.

[0089] The various parts of the photovoltaic module refer to the above-mentioned related records and can achieve similar beneficial effects. In order to avoid repetition, they will not be described here.

[0090] Optional, see Figure 2 , Fig.13 , Fig.14 As shown, the front encapsulation film 5 located on the light-facing side of the solar cell 4 includes: a base film portion and a protruding portion protruding from the base film portion. The height of the protruding portion protruding from the base film portion can be set according to actual needs, and the embodiment of the present invention does not specifically limit this. In the photovoltaic module, the solar cell connection layer is tilted in the concave space formed by the base portion and the protruding portion in the connection layer, and the base film portion and the protruding portion in the front encapsulation film. The concave space formed by the two is larger, which is convenient for the tilted placement of the solar cell.

[0091] In the photovoltaic module, the raised portions in the connecting layer and the raised portions in the front packaging film on both sides of the same solar cell are staggered, and the raised surfaces of the raised portions of the front packaging film are opposite to the light-facing surfaces of the solar cells 4, thereby facilitating the tilted placement of the solar cells. Moreover, the raised portions in the connecting layer and the raised portions in the front packaging film are not opposite to each other, which can reduce hidden cracks in the lamination process.

[0092] The front encapsulation film 5 can be only a front encapsulation film or a combination of a front encapsulation film and a cover plate. It should be noted that the front encapsulation film and the cover plate have good light transmittance, for example, the light transmittance of the front encapsulation film and the cover plate in the visible light band is greater than or equal to 80%. In the embodiment of the present invention, this is not specifically limited.

[0093] The base film portion in the front packaging film and the protruding portion protruding from the base film portion can be formed integrally or in steps, and the materials of the two can be the same or different, which is not specifically limited in the embodiments of the present invention.

[0094] The solar cell 4 is tiltedly arranged in the concave space formed by the base part and the protruding part in the connection layer, and the base film part and the protruding part in the front packaging film, which is equivalent to placing the solar cell in the groove formed by the connection layer and the front packaging film, which can reduce the pressure on the solar cell during the lamination process, reduce hidden cracks, and improve production yield. In addition, the positioning is more accurate, which is convenient for laying and aligning the solar cell and improves production efficiency.

[0095] Optionally, the material of the base film portion of the front packaging film may be selected from at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel.

[0096] Optionally, the protruding parts are periodically distributed in the front packaging film, and the process is simple. For example, refer to Figure 2 , Fig.13 , Fig.14 As shown, the protruding portions are periodically distributed in the front packaging film 5 .

[0097] The present invention also provides a method for preparing a photovoltaic module, the method comprising the following steps:

[0098] Step SA1, providing any conductive backplane as described above.

[0099] Step SA2, providing a solar cell, wherein the solar cell has a back electrode.

[0100] Step SA3, obliquely laying solar cells in the concave space formed by the base part and the raised part in the connecting layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connecting layer, and the raised surface of the raised part is opposite to the backlight surface of the solar cell.

[0101] Step SA4, laminating the stack including the component precursor so that the back electrode of the solar cell is electrically connected to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

[0102] The stack including the aforementioned component precursor may be: the light-facing surface of the component precursor may also be paved with a front encapsulation film and a cover plate. The various parts in the photovoltaic component refer to the aforementioned related records, and similar beneficial effects can be achieved. In order to avoid repetition, they will not be described here. The lamination temperature can be 140°C-160°C. It should be noted that the lamination process in step SA4 can perform secondary hot pressing and bonding on the connecting layer, the conductive layer, and the back film layer in the conductive backplane, which can further deform the conductive particles in each conductive area in the connecting layer to increase the contact with the adjacent conductive particles and adjacent surfaces in the conductive area, thereby forming a good current path.

[0103] It should be noted that the method for preparing the photovoltaic module can also first stack a front packaging film on the backlight surface of the cover plate, then lay solar cells on the backlight surface of the front packaging film, and then arrange the above-mentioned conductive backplane on the backlight surface of the solar cells. In the embodiments of the present invention, this is not specifically limited.

[0104] The embodiment of the present invention also provides another method for preparing a photovoltaic module, the production method comprising the following steps:

[0105] Step SI, providing a connecting layer; the connecting layer includes: a base portion and a protruding portion protruding from the base portion; the connecting layer has a conductive area for electrically connecting the back electrode of the solar cell and the conductive circuit, and an insulating area for blocking the adjacent conductive area; the conductive area and the insulating area both penetrate the connecting layer; the connecting layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive area.

[0106] Step SII, providing a backing film layer.

[0107] Step SIII, providing a conductive layer.

[0108] Step SIV, providing a solar cell, wherein the solar cell has a back electrode.

[0109] Step SV, stacking the connecting layer, the conductive layer, and the back film layer in sequence, and obliquely laying the solar cells in the concave space formed by the base part and the raised part in the connecting layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connecting layer, and the raised surface of the raised part is opposite to the backlight surface of the solar cell.

[0110] Step SVI, laminating the stack including the component precursor so that the back electrode of the solar cell is electrically connected to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

[0111] Specifically, the stacked parts including the aforementioned component precursor can be: the light-facing surface of the component precursor can also be paved with a front encapsulation film and a cover plate. In the steps of this method, the connecting layer, the conductive layer, and the back film layer constituting the conductive backplane are not specifically hot-pressed and bonded, but the hot-pressing bonding of the connecting layer, the conductive layer, and the back film layer is completed by lamination in the process of forming the photovoltaic component, thereby reducing the hot-pressing steps, thereby reducing the production steps, improving the production efficiency, reducing the energy consumption, and reducing the production cost. The various parts of the photovoltaic component in this method can refer to the aforementioned related records, and can achieve similar beneficial effects. In order to avoid repetition, they will not be repeated here.

[0112] It should be noted that the method for preparing the photovoltaic module can also be carried out by first stacking a front packaging film on the backlight surface of the cover plate, then laying solar cells on the backlight surface of the front packaging film, and then sequentially arranging the above-mentioned connecting layer, conductive layer, and back film layer on the backlight surface of the solar cells. In the embodiments of the present invention, this is not specifically limited.

[0113] Optionally, in the above two methods for preparing photovoltaic modules, the lamination process may include: secondary hot pressing and laminating. The stack including the module precursor is first hot pressed and laminated; the stack including the module precursor is again hot pressed and laminated. The temperature of the first hot pressing and laminating may be lower than the temperature of the second hot pressing and laminating. For example, the temperature of the first hot pressing and laminating is: 80-125°C, and the temperature of the second hot pressing and laminating is: 120-160°C. By performing the first hot pressing and laminating of the above-mentioned stack at a relatively low temperature, the protruding portion of the connecting layer in the conductive backplane of the above-mentioned stack, and / or the protruding portion of the front packaging film can be fully melted and flowed evenly and stably to the interconnection before the cross-linking reaction, thereby generating a uniform static pressure. Then, the preheated stack is again hot pressed and laminated at a higher temperature, and can be filled and cured into the gap of the battery string or module under uniform static pressure, so that a gapless connection can be achieved, which can further reduce hidden cracks or cracks.

[0114] It should be noted that in the above two method embodiments, each surface of the front encapsulation film in the stack can be a plane, or the front encapsulation film includes: a base film portion and a convex portion protruding from the base film portion. In the photovoltaic module, the solar cell is tilted in the concave space formed by the base portion and the convex portion in the connecting layer, and the base film portion and the convex portion in the front encapsulation film. The convex portion in the connecting layer and the convex portion in the front encapsulation film on both sides of the same solar cell are staggered, and the convex surface of the convex portion is opposite to the light-facing surface of the solar cell. That is, the solar cell is tilted in the concave space formed by the connecting layer and the front encapsulation film.

[0115] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A conductive backplane, characterized in that: The conductive backplane comprises: a connection layer, a back film layer, and a conductive layer located between the connection layer and the back film layer; the conductive layer has a conductive circuit; The connecting layer comprises: a base portion and a protruding portion protruding from the base portion; The connecting layer has a conductive area for electrically connecting the back electrode of the solar cell and the conductive circuit, and an insulating area for blocking the adjacent conductive area; both the conductive area and the insulating area penetrate the connecting layer; the connecting layer includes an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive area.

2. The conductive backplane according to claim 1, characterized in that: The protruding portions are periodically distributed in the connection layer.

3. The conductive backplane according to claim 1, characterized in that: The heights of the conductive area and the insulating area located on the base portion are equal to the height of the base portion.

4. The conductive backplane according to claim 1 or 2, characterized in that: In a direction parallel to the back film layer, a distance between centers of two adjacent protruding portions is less than or equal to a length of one solar cell.

5. The conductive backplane according to claim 1 or 2, characterized in that: The height of the protruding portion protruding from the base portion is 20-200 um.

6. The conductive backplane according to claim 1 or 2, characterized in that: In the arrangement direction of the connection layer and the back film layer, the cross-sectional shape of the protruding portion includes: a triangle, a rectangle, an arc, and a wave.

7. The conductive backplane according to claim 1 or 2, characterized in that: The width of each of the conductive areas is less than or equal to the width of the back electrode to be electrically connected.

8. The conductive backplane according to claim 1 or 2, characterized in that: The conductive particles are made of at least one of silver particles, copper particles, aluminum particles, indium alloy particles, tin alloy particles, silver-coated copper particles, graphene particles, graphene oxide particles, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) particles, and silver-coated thermoplastic polymer particles; The conductive particles are in at least one of a spherical shape, a quasi-spherical shape, and an irregular shape; The average particle size of the conductive particles is 0.1-100 um.

9. The conductive backplane according to claim 1 or 2, characterized in that: After being heated and / or pressurized, the series resistivity of the connecting layer and the conductive layer in the vertical direction is less than 1Ω·cm 2 .

10. The conductive backplane according to claim 1 or 2, characterized in that: The material of the insulating base film is selected from at least one of epoxy resin, acrylic resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel.

11. The conductive backplane according to claim 1 or 2, characterized in that: The conductive layer is a patterned metal foil or a plurality of conductive lines arranged on an adhesive film.

12. A method for producing a conductive backplane, characterized in that: The steps include: Provides a connection layer; The connection layer comprises: a base portion and a protruding portion protruding from the base portion; the connection layer has a conductive region for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating region for blocking adjacent conductive regions; both the conductive region and the insulating region penetrate the connection layer; the connection layer comprises an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive region; Providing a back film layer and a conductive layer; the conductive layer has the conductive circuit; The connection layer, the conductive layer and the back film layer are stacked in sequence and bonded by heat pressing.

13. The method for producing a conductive backplane according to claim 12, characterized in that: The step of providing a connection layer comprises: The insulating base film precursor particles and the mixture of the insulating base film precursor particles and the conductive particles are extruded, cast and cooled to form the connection layer.

14. The method for producing a conductive backplane according to claim 12, characterized in that: The hot pressing temperature is 60-120°C, the pressure is 0.01-0.2MPa, and the hot pressing time is 1-30min.

15. The method for producing a conductive backplane according to claim 12, characterized in that: The base portion and the raised portion are integrally formed.

16. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells, each of which has a back electrode, and the back electrode of the solar cell and the conductive circuit of the conductive back plate are electrically connected by using the conductive area in the conductive back plate as claimed in any one of claims 1 to 11; In the packaging process of forming the assembly, the solar cell is tiltedly arranged in the concave space formed by the base part and the convex part in the connection layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell; There is an adhesive medium between adjacent solar cells, and the adhesive medium is formed by melting and flowing of the insulating base film of the protruding part of the connecting layer during the lamination process.

17. The photovoltaic module according to claim 16, characterized in that: The front encapsulation adhesive film located on the light-facing surface of the solar cell comprises: a base film portion and a protruding portion protruding from the base film portion; The base part and the protruding part in the connecting layer, and the base film part and the protruding part in the front encapsulation film, together form a concave space, and the solar cell is tiltedly arranged in the concave space; In the photovoltaic module, the raised portions in the connection layer and the raised portions in the front packaging film on both sides of the same solar cell are alternately distributed, and the raised surfaces of the raised portions of the front packaging film are opposite to the light-facing surfaces of the solar cell.

18. The photovoltaic module according to claim 17, characterized in that: The protruding portions are periodically distributed in the front packaging film.

19. A method for preparing a photovoltaic module, characterized in that: The steps include: Providing a conductive backplane as claimed in any one of claims 1 to 11; Providing a solar cell having a back electrode; The solar cell is obliquely laid in the concave space formed by the base part and the convex part in the connection layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connection layer, and the convex surface of the convex part is opposite to the backlight surface of the solar cell; The stack including the component precursor is laminated to electrically connect the back electrode of the solar cell to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

20. A method for preparing a photovoltaic module, characterized in that: The steps include: Provides a connection layer; The connection layer comprises: a base portion and a protruding portion protruding from the base portion; the connection layer has a conductive region for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating region for blocking adjacent conductive regions; both the conductive region and the insulating region penetrate the connection layer; the connection layer comprises an insulating base film, and conductive particles dispersed in the insulating base film; the conductive particles are located in the conductive region; Providing a backing film layer; providing a conductive layer; Providing a solar cell having a back electrode; The connecting layer, the conductive layer, and the back film layer are stacked in sequence, and the solar cell is obliquely laid in the concave space formed by the base part and the raised part in the connecting layer to obtain a component precursor, so that the back electrode of the solar cell is arranged opposite to the conductive area in the connecting layer, and the raised surface of the raised part is opposite to the backlight surface of the solar cell; The stack including the component precursor is laminated to electrically connect the back electrode of the solar cell to the conductive area in the conductive backplane, and the insulating base film of the raised portion in the connecting layer melts during the lamination process and flows between adjacent solar cells to form an adhesive medium.

21. The method for preparing a photovoltaic module according to claim 19 or 20, wherein the lamination process comprises secondary hot pressing bonding.

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