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

Abstract

The present invention provides a conductive backplane and a production method, a photovoltaic module and a production 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 connecting layer and the back film layer; 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 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. Only one connecting layer in the conductive backplane realizes electrical connection and insulation at the same time, without opening holes and setting conductive materials, the process is simple, and there are no openings, which will not damage the integrity of the connecting layer, so that the conductive backplane is stable and reliable, and has good insulation effect.

Description

Technical Field

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

[0002] Back-contact solar cells are usually electrically interconnected via a conductive backsheet to form a photovoltaic module.

[0003] In the current conductive backplane, an opening is provided on the insulating layer at a position opposite to the electrode of the back contact solar cell. In the subsequent use process, a conductive material is placed in the opening to achieve a conductive connection between the back electrode of the solar cell and the conductive circuit of the conductive circuit layer, and the insulating layer at the remaining position realizes an insulating effect.

[0004] However, the existing conductive backplane needs to be provided with conductive materials in the openings during use, which results in a complex process and poor stability and reliability. Summary of the invention

[0005] The present invention provides a conductive back plate and a production method, a photovoltaic module and a production method, aiming to solve the problem that the existing conductive back plate needs to arrange conductive materials in the openings, the process is complicated, and the stability and reliability are poor.

[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 circuit layer located between the connection layer and the back film layer; the conductive circuit layer has a conductive circuit;

[0007] 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 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.

[0008] The electrical connection between the back electrode of the solar cell in the conductive area in the connecting layer of the above-mentioned conductive backplane and the conductive circuit of the conductive circuit layer in the conductive backplane is achieved through the insulating area in the connecting layer of the conductive backplane. That is to say, only one connecting layer in the conductive backplane achieves electrical connection and insulation at the same time, without the need to open holes and then set conductive materials. The process is simple, and at the same time, there are no openings, which will not damage the integrity of the connecting layer. Therefore, the conductive backplane has high stability and reliability and good insulation effect.

[0009] Optionally, the material of the conductive particles is selected from at least one of: silver particles, copper particles, aluminum particles, tin particles, indium alloy particles, tin alloy particles, silver-coated copper particles, and silver-coated thermoplastic polymer particles;

[0010] The conductive particles are in at least one of a spherical shape, a quasi-spherical shape, and an irregular shape;

[0011] The average particle size of the conductive particles is 0.1-100 um.

[0012] Optionally, in the silver-coated thermoplastic polymer particles, the thickness of silver is less than 300 nm, and the average particle size of the thermoplastic polymer particles is 50-80 um.

[0013] Optionally, the material of the insulating base film is selected from at least one of epoxy resin, acrylic resin, fluororesin, polysulfone resin, polyester resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel.

[0014] Optionally, the thickness of the connecting layer is 50-500um;

[0015] The light transmittance of the entire connecting layer is less than or equal to 90%;

[0016] The light transmittance of the insulating area is greater than 90%.

[0017] Optionally, the conductive area is divided into a first conductive area for electrically connecting to the back electrode at the emitter of the solar cell, and a second conductive area for electrically connecting to the back electrode at the field area of ​​the solar cell, and the first conductive area and the second conductive area are spaced apart; the span of the first conductive area is greater than or equal to the span of the second conductive area.

[0018] Optionally, the conductive area is in the shape of a continuous strip or a discontinuous dot.

[0019] Optionally, the conductive particles are deformable when subjected to heat and / or pressure.

[0020] Optionally, the conductive particles have a widening ratio of 1.2 to 1.8 times after being heated and / or pressed.

[0021] Optionally, after being heated and / or pressed, the contact resistivity between the conductive area and the conductive circuit layer in the vertical direction is less than or equal to 2Ω·cm 2 .

[0022] According to a second aspect of the present invention, there is provided a method for producing a conductive backplane, comprising the following steps:

[0023] Providing a connection layer; the connection layer has a conductive area for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating area for blocking the adjacent conductive area; 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;

[0024] Providing a back film layer and a conductive circuit layer;

[0025] The connection layer, the conductive circuit layer and the back film layer are stacked in sequence and bonded by heat pressing.

[0026] The conductive backplane production method has the same or similar beneficial effects as the aforementioned conductive backplane, and will not be described in detail here to avoid repetition.

[0027] Optionally, the step of providing a connection layer includes:

[0028] Conductive particles are locally added to the insulating base film precursor melt, and then extruded, cast, and cooled to form the connection layer.

[0029] By adding a plurality of conductive particles to the insulating base film precursor melt to obtain the conductive area precursor melt, the conductive area precursor melt is extruded, cast, and cooled to form the conductive area. In the process of obtaining the connection layer, there is no need to set an opening on the insulating base film, thus avoiding the complicated operation of the opening. The process is simple, which can greatly improve the production efficiency and avoid the damage to the connection layer material during the opening process. The strength of the connection layer of the embodiment of the present invention is much higher than that of the conventional insulating layer with a large number of openings, so it can improve the bonding strength and reliability between the conductive backplane and the solar cell. At the same time, since the damage to the connection layer material during the opening process is avoided, the insulation effect of the insulating area is better.

[0030] Optionally, 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.

[0031] According to a third aspect of the present invention, there is provided a photovoltaic module comprising a plurality of solar cells having back electrodes, wherein the back electrodes of the solar cells and the conductive circuits of the conductive backplane are electrically connected by using a conductive area in a conductive backplane as described above.

[0032] Optionally, the projection of the conductive area of ​​the connecting layer in the conductive backplane is located within the projection of the back electrode.

[0033] The photovoltaic module has the same or similar beneficial effects as the aforementioned conductive backplane, and will not be described again here to avoid repetition.

[0034] According to a fourth aspect of the present invention, there is provided a method for producing a photovoltaic module, comprising the following steps:

[0035] Providing a conductive back plate as described above;

[0036] Providing a solar cell having a back electrode;

[0037] The solar cell and the conductive back sheet are stacked and laminated so that the back electrode of the solar cell is electrically connected to the conductive area in the conductive back sheet.

[0038] The photovoltaic module production method has the same or similar beneficial effects as the aforementioned conductive backplane, and will not be described again here to avoid repetition.

[0039] According to a fifth aspect of the present invention, another method for producing a photovoltaic module is provided, comprising the following steps:

[0040] Providing a connection layer; the connection layer has a conductive area for electrically connecting the back electrode of the solar cell and the conductive line, and an insulating area for blocking adjacent conductive areas; 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;

[0041] Providing a backing film layer;

[0042] Providing a conductive circuit layer;

[0043] Providing a solar cell having a back electrode;

[0044] The solar cell, the connection layer, the conductive circuit layer, and the back film layer are stacked and laminated in sequence, so that the back electrode of the solar cell is in electrical contact with the conductive area in the connection layer.

[0045] The photovoltaic module production method achieves the same or similar beneficial effects as the above-mentioned conductive backplane. At the same time, the connection layer, conductive circuit layer, and back film layer that constitute the conductive backplane are not specially hot-pressed and bonded. Instead, the hot-pressing bonding of the connection layer, conductive circuit layer, and back film layer is 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

[0046] 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.

[0047] Figure 1 A schematic structural diagram of a conductive backplane in an embodiment of the present invention is shown;

[0048] Figure 2 A schematic structural diagram of a photovoltaic module in an embodiment of the present invention is shown;

[0049] Figure 3 A schematic structural diagram of a conductive circuit layer in an embodiment of the present invention is shown;

[0050] Figure 4 A partial structural schematic diagram of an insulating base film extrusion device in an embodiment of the present invention is shown.

[0051] Description of the accompanying drawings:

[0052] 1-back film layer, 2-conductive circuit layer, 3-connecting layer, 4-solar cell, 41-back electrode, 31-conductive area, 32-insulating area, 33-insulating base film, 34-conductive particles, 51-first area of ​​insulating base film extrusion equipment, 52-second area of ​​insulating base film extrusion equipment. DETAILED DESCRIPTION

[0053] 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.

[0054] In the embodiment of the present invention, referring to Figure 1 As shown, Figure 1 A schematic structural diagram of a conductive backplane in an embodiment of the present invention is shown. The conductive backplane includes: a connecting layer 3 and a back film layer 1, and a conductive circuit layer 2 located between the connecting layer 3 and the back film layer 1. The conductive circuit layer 2 has a conductive circuit. The connecting layer 3 has a conductive area 31 for electrically connecting the back electrode of the solar cell to the conductive circuit, and an insulating area 32 that blocks adjacent conductive areas. The connecting layer includes an insulating base film 33 and conductive particles 34 dispersed in the insulating base film 33. The conductive particles 34 are located in the conductive area 31. The number of conductive particles 34 included in each conductive area 31 is not specifically limited, so that the area can be flexibly set for the purpose of conduction. Refer to Figure 2 As shown, Figure 2The schematic diagram of the structure of a photovoltaic module in an embodiment of the present invention is shown. The conductive area 31 is used to electrically connect the back electrode 41 of the solar cell 4 and the conductive circuit of the conductive circuit layer 2 in the conductive backplane. The electrical connection between the solar cell 4 and the conductive circuit of the conductive circuit layer 2 is achieved through the conductive area 31 in the connection layer 3 of the conductive backplane, and the insulation effect is achieved through the insulating area 32 in the connection layer 3 of the conductive backplane. That is to say, only one layer of the connection layer 3 in the conductive backplane realizes electrical connection and insulation at the same time, without opening holes and setting conductive materials, and the process is simple. At the same time, without opening holes, the integrity of the connection layer 3 will not be damaged, and the conductive backplane is stable and reliable.

[0055] Optional, see Figure 1 As shown, the thickness d of the connection layer 3 is 50-500 um. The connection layer within this thickness range makes the series resistance between the back electrode, the conductive area, and the conductive circuit of the conductive circuit layer of the solar cell small.

[0056] 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 circuit 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 circuit layer increases, which is beneficial to enhance the conductive effect in the vertical direction.

[0057] Since the conductive particles are deformable during the heating and / or pressure process, the lateral area of ​​each conductive particle in the conductive region increases during the pressure and / or heating process. Figure 2 As shown, in the photovoltaic module, in the vertical direction, the projection of the conductive area 31 of the connection layer 3 in the conductive backplane can be located within the projection of the electrically connected back electrode, thereby avoiding short circuits caused by increased lateral area due to pressure and / or heat. It should be noted that the vertical direction is: the stacking direction of the connection layer, the conductive circuit layer, and the back film layer in the conductive backplane or battery module, such as, Figure 1 Indicated L1.

[0058] 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 of the solar cell, the conductive area, and the conductive circuit layer.

[0059] Optionally, the width of the conductive particles after being heated and / or pressed is 1.2 to 1.8 times. That is, after the conductive particles are heated and / or pressed, the volume or size of the conductive particles is 1.2-1.8 times that before being heated and / or pressed, that is, during the heating and / or pressing process, due to the deformability of the conductive particles, the volume or size of the conductive particles is expanded by 1.2-1.8 times. Between adjacent insulating regions, the span of each conductive region can avoid short circuits caused by the widening of the conductive particles during heating and / or pressing, and the lateral area of ​​the conductive particles increases during the pressing and / or heating process, and the contact area with the back electrode and the conductive circuit layer increases, which is conducive to enhancing the conductive effect in the vertical direction.

[0060] For example, before being heated and / or pressed, the span of each conductive region between adjacent insulating regions is less than or equal to 80% of the span of the electrically connected back electrode. After being heated and / or pressed, the span of each conductive region is not greater than 120% of the span of the electrically connected back electrode. Furthermore, after being heated and / or pressed, the span of each conductive region between adjacent insulating regions is not greater than 120% of the span of the electrically connected back electrode, which can avoid short circuits caused by the widening of conductive particles during heating and / or pressing.

[0061] Optionally, the conductive area is divided into a first conductive area and a second conductive area, and the first conductive area and the second conductive area are spaced apart, that is, a second conductive area is set between two first conductive areas, or a first conductive area is set between two second conductive areas. Between adjacent insulating areas, the span of the first conductive area is greater than or equal to the span of the second conductive area. The first conductive area is used for subsequent electrical connection to the back electrode at the emitter of the solar cell, and the second conductive area is used for electrical connection to the back electrode at the field area of ​​the solar cell, which is beneficial to improve the current collection efficiency and improve the battery efficiency. It should be noted that the back electrode at the field area is the back electrode corresponding to the surface field. Between adjacent insulating areas, the span of the first conductive area can be the size of the first conductive area in the direction from one insulating area to the insulating area adjacent to it. For example, Figure 1 In the direction indicated by L2, the size of the first conductive region is the span of the first conductive region between adjacent insulating regions.

[0062] Optionally, after being heated and / or pressed, the contact resistivity between the conductive area and the conductive circuit layer in the vertical direction is less than or equal to 2Ω·cm 2 Furthermore, after being heated and / or pressed, the back electrode, the conductive area, and the conductive circuit layer of the solar cell have good conductive effects.

[0063] Optionally, the insulating base film in the connecting layer can be a transparent insulating base film or an opaque insulating base film. If the insulating base film in the connecting layer is a transparent insulating base film, it is beneficial to the accurate alignment of the back electrode of the subsequent solar cell and the conductive area of ​​the connecting layer, and at the same time can improve the light transmittance of the backlight surface of the solar cell and increase the utilization rate of light.

[0064] Optionally, the transmittance of the entire connecting layer is less than or equal to 90%, and further, the proportion of conductive particles in the conductive area of ​​the connecting layer is relatively large, so that the conductive effect between the back electrode, the conductive area, and the conductive circuit layer of the solar cell is good. For example, the transmittance of the entire connecting layer is less than or equal to 90%, and greater than or equal to 50%.

[0065] Optionally, the light transmittance of the insulating area is greater than 90%. When the above-mentioned photovoltaic module is a double-sided module, there is less light blocking, which can increase the utilization rate of light, help improve the photoelectric conversion efficiency, and facilitate the accurate alignment of the subsequent back electrode of the solar cell and the conductive area of ​​the connecting layer.

[0066] Optionally, the conductive particles are made of at least one of silver particles, copper particles, aluminum particles, tin particles, indium alloy particles, tin alloy particles, silver-coated copper 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.

[0067] 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.

[0068] 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 after lamination, that is, the direction relative to the conductive circuit layer of the conductive backplane of the battery back electrode. 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.

[0069] The thickness of the connecting layer is 50-500um, and the average particle size of the conductive particles is 0.1-100um. 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.

[0070] Optionally, if the conductive particles are made of silver-coated thermoplastic polymer particles, the thickness of silver in the silver-coated thermoplastic polymer particles is less than 300 nm, and the average particle size of the thermoplastic polymer particles is 50-80 μm, the above material has good deformation during heating and / or pressure, which helps to form close electrical contact with the back electrode and the conductive circuit layer after hot pressing, and the above conductive particles have good conductive effect. For example, the thermoplastic polymer particles can be PMMA (polymethyl methacrylate).

[0071] Optionally, the insulating region in the connection layer may be an insulating base film, and the insulating base film in the conductive region in the connection layer and the insulating base film in the insulating region may be made of at least one of epoxy resin, acrylic resin, fluororesin, polysulfone resin, polyester 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.

[0072] Compared with the insulating layer formed by multi-layer composite in the conductive backplane in the prior art, the connection layer in the embodiment of the present invention does not have multi-layer composite, and thus will not have reliability problems such as delamination or bonding failure. At the same time, there is no need for multi-layer composite, the manufacturing process is simple, and it is conducive to reducing costs.

[0073] The above-mentioned conductive circuit layer can be a patterned layer, such as Figure 3 As shown, Figure 3 A schematic diagram of the structure of a conductive circuit layer in an embodiment of the present invention is shown. The conductive areas of the connecting layer are aligned with different areas of the patterned layer to connect the positive and negative electrodes of the backlight surface of the solar cell. The conductive circuit layer can be a patterned layer formed by patterning a conductive metal foil. The patterning method includes mechanical punching, laser punching or chemical etching. The pattern depends on the pattern of the electrode on the backlight surface of the solar cell, and the pattern may include a variety of shapes and / or sizes. The conductive metal foil can be copper foil or aluminum foil or any other suitable metal or metal alloy. The thickness of the conductive metal foil can provide a current path with low resistance. If the conductive metal foil is selected from copper foil or aluminum foil, the thickness can be 20-100um. Or 30-60um.

[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 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 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 circuit layer;

[0078] Step S3, stacking the connection layer, the conductive circuit 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 circuit 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 backplane is stacked with the solar cell, the packaging material, 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: locally adding conductive particles to the insulating base film precursor melt, and then forming the connection layer by extrusion, casting, and cooling.

[0083] Specifically, refer to Figure 4 As shown, Figure 4 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 an insulating base film precursor melt, and the insulating base film precursor melt in the first zone 51 is extruded, cast, and cooled to form an insulating zone of a connecting layer. The second zone 52 is filled with an insulating base film precursor melt, and conductive particles are added to the insulating base film precursor melt in the second zone 52. The insulating base film precursor melt with conductive particles added in the second zone 52 is 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.

[0084] In the embodiment of the present invention, conductive particles are locally added to the insulating base film precursor melt, and then extruded, cast, and cooled to form a connecting layer. In the process of obtaining the connecting layer, it is not necessary to set an opening on the insulating base film, which avoids the complicated operation of the opening. The process is simple, which can greatly improve the production efficiency and avoid the damage to the connecting layer material during the opening process. The strength of the connecting layer in the embodiment of the present invention is much higher than that of the conventional insulating layer with a large number of openings, so it can improve the bonding strength and reliability between the conductive backplane and the solar cell. At the same time, since the damage to the connecting layer material during the opening process is avoided, the insulation effect of the insulating area is better.

[0085] The embodiment of the present invention further provides a photovoltaic module, such as Figure 2 As shown, it includes a plurality of solar cells 4, each of which has a back electrode 41, and the conductive area 31 in any of the aforementioned conductive back sheets is used to electrically connect the back electrodes 41 of the solar cells 4 and the conductive circuits of the conductive circuit layer 2 of the conductive back sheet. The various parts of the photovoltaic module refer to the aforementioned related records, and can achieve similar beneficial effects. In order to avoid repetition, they are not described here.

[0086] Optionally, in the above photovoltaic module, refer to Figure 1 As shown, in the vertical direction L1, the projection of the conductive area 31 of the connection layer 3 in the conductive backplane is located within the projection of the electrically connected back electrode, thereby avoiding short circuits caused by increased lateral area due to pressure and / or heat. It should be noted that the vertical direction is the stacking direction of the connection layer, the conductive circuit layer, and the back film layer in the conductive backplane or battery assembly.

[0087] The present invention also provides a photovoltaic module production method, which comprises the following steps:

[0088] Step SA1, providing any conductive backplane as described above.

[0089] Step SA2, providing a solar cell, wherein the solar cell has a back electrode.

[0090] Step SA3, stacking and laminating the solar cell and the conductive back sheet, so that the back electrode of the solar cell is electrically connected to the conductive area in the conductive back sheet.

[0091] 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 are not described here. The lamination temperature can be 140°C-160°C. It should be noted that the lamination process in step SA3 can perform secondary hot pressing and laminating on the connecting layer, the conductive circuit layer, and the back film layer in the conductive backplane, which can further deform the conductive particles in a conductive area in the connecting layer to increase the contact with the adjacent conductive particles and adjacent surfaces in the conductive area, forming a good current path.

[0092] The embodiment of the present invention also provides another photovoltaic module production method, which comprises the following steps:

[0093] Step SI, providing a connecting layer; 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 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.

[0094] Step SII, providing a backing film layer.

[0095] Step SIII: providing a conductive circuit layer.

[0096] Step SIV, providing a solar cell, wherein the solar cell has a back electrode.

[0097] Step SV, stacking and laminating the solar cell, the connection layer, the conductive circuit layer, and the back film layer in sequence, so that the back electrode of the solar cell is in electrical contact with the conductive area in the connection layer.

[0098] Specifically, in the steps of the method, the connection layer, the conductive circuit layer, and the back film layer constituting the conductive backplane are not specifically hot-pressed and bonded, but the hot-pressing and bonding of the connection layer, the conductive circuit layer, and the back film layer is completed by lamination in the process of forming the photovoltaic module, 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 module in the method can refer to the above-mentioned related records, and can achieve similar beneficial effects. In order to avoid repetition, they will not be repeated here.

[0099] 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 circuit layer located between the connection layer and the back film layer; the conductive circuit layer has a conductive circuit; The connection layer has a conductive area for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating area for blocking the adjacent conductive area; 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; the material of the insulating base film is selected from: at least one of epoxy resin, acrylic resin, fluororesin, polysulfone resin, polyester resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel; The connection layer is formed by locally adding conductive particles to the insulating base film precursor melt, followed by extrusion, casting and cooling.

2. The conductive backplane according to claim 1, characterized in that: The conductive particles are made of at least one of silver particles, copper particles, aluminum particles, tin particles, indium alloy particles, tin alloy particles, silver-coated copper 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.

3. The conductive backplane according to claim 2, characterized in that: In the silver-coated thermoplastic polymer particles, the thickness of silver is less than 300 nm, and the average particle size of the thermoplastic polymer particles is 50-80 um.

4. The conductive backplane according to claim 1, characterized in that: The thickness of the connecting layer is 50-500um; The light transmittance of the entire connecting layer is less than or equal to 90%; The light transmittance of the insulating area is greater than 90%.

5. The conductive backplane according to claim 1, characterized in that: The conductive area is divided into a first conductive area for electrically connecting to the back electrode at the emitter of the solar cell, and a second conductive area for electrically connecting to the back electrode at the field area of ​​the solar cell. The first conductive area and the second conductive area are distributed at intervals; the span of the first conductive area is greater than or equal to the span of the second conductive area.

6. The conductive backplane according to claim 1, characterized in that: The conductive area is in the shape of a continuous strip or a discontinuous dot.

7. The conductive backplane according to claim 1, characterized in that: The conductive particles are deformable when subjected to heat and / or pressure; The conductive particles have a width expansion ratio of 1.2 to 1.8 times after being heated and / or pressed; After being heated and / or pressed, the contact resistivity between the conductive area and the conductive circuit layer in the vertical direction is less than or equal to 2Ω·cm 2 .

8. A method for producing a conductive backplane, characterized in that: The steps include: Provides a connection layer; The connection layer has a conductive area for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating area for blocking adjacent conductive areas; 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; Providing a back film layer and a conductive circuit layer; The connection layer, the conductive circuit layer, and the back film layer are stacked in sequence and laminated by hot pressing; The material of the insulating base film is selected from at least one of epoxy resin, acrylic resin, fluororesin, polysulfone resin, polyester resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel; The step of providing the connection layer includes: locally adding conductive particles into the insulating base film precursor melt, and then extruding, casting, and cooling to form the connection layer.

9. The method for producing a conductive backplane according to claim 8, 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.

10. A photovoltaic module, characterized in that: It comprises a plurality of solar cells, each of which has a back electrode, and adopts the conductive area in the conductive backplane as claimed in any one of claims 1 to 7 to electrically connect the back electrodes of the solar cells and the conductive circuits of the conductive backplane. 11 . The photovoltaic module according to claim 10 , wherein in the vertical direction, a projection of the conductive area of ​​the connecting layer in the conductive back sheet is located within a projection of the back electrode.

12. A method for producing a photovoltaic module, characterized in that: The steps include: Providing a conductive backplane as claimed in any one of claims 1 to 7; Providing a solar cell having a back electrode; The solar cell and the conductive back sheet are stacked and laminated so that the back electrode of the solar cell is electrically connected to the conductive area in the conductive back sheet.

13. A method for producing a photovoltaic module, characterized in that: The steps include: Provides a connection layer; The connection layer has a conductive area for electrically connecting the back electrode of the solar cell with the conductive circuit, and an insulating area for blocking adjacent conductive areas; 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; Providing a backing film layer; Providing a conductive circuit layer; The conductive circuit layer has the conductive circuit; Providing a solar cell having a back electrode; The solar cell, the connection layer, the conductive circuit layer, and the back film layer are stacked and laminated in sequence, so that the back electrode of the solar cell is in electrical contact with the conductive area in the connection layer; The material of the insulating base film is selected from at least one of epoxy resin, acrylic resin, fluororesin, polysulfone resin, polyester resin, polyurethane, cyanoacrylate, polyvinyl alcohol, polydimethylsiloxane, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, polyvinyl butyral or silica gel; The connection layer is formed by locally adding conductive particles to the insulating base film precursor melt, followed by extrusion, casting and cooling.

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