Integrated thin-film photovoltaic battery group, double-sided photovoltaic module and preparation method

Abstract

The present invention belongs to the technical field of photovoltaic modules, and specifically relates to an integrated thin-film photovoltaic battery group, a double-sided photovoltaic module and a preparation method. The battery group includes a substrate, a first electrode layer, a photovoltaic functional layer including a first charge transport layer and a second charge transport layer, and a second electrode layer. The first surface of the substrate has a series groove, and the series groove has a mask wall B with an angle of 45° to 90° with the substrate reference plane A. In the z direction of the substrate, the depth of the mask wall B is greater than the sum of the thickness of the first electrode layer and the photovoltaic functional layer not including the second charge transport layer and is less than the total thickness of the first electrode layer, the photovoltaic functional layer and the second electrode layer. The first electrode layer, the photovoltaic functional layer and the second electrode layer are sequentially prepared on the projection surface of the x-y plane of the first surface of the substrate, and each monomer thin-film photovoltaic cell is formed by means of the series groove. The first electrode layer of the monomer thin-film photovoltaic cell and the second electrode layer of the adjacent monomer thin-film photovoltaic cell are connected in series to form a battery group, which significantly improves the photoelectric conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic modules, and in particular to an integrated thin-film photovoltaic battery group, a double-sided photovoltaic module and a preparation method thereof. Background Art

[0002] 1. Existing integrated thin-film photovoltaic battery groups, especially those made of perovskite materials, rely on mechanical or laser division to segment single photovoltaic cells. The divided areas will produce mechanical and thermal damage, and the dead areas caused by damage and local short circuits will cause losses in the active area of ​​the battery group, directly reducing the photoelectric conversion efficiency of the photovoltaic battery group. The finer the division, the greater the current and voltage losses, while the coarser division will aggravate the current loss caused by resistance.

[0003] Second, the existing integrated thin-film photovoltaic battery group, especially the integrated thin-film photovoltaic battery group of perovskite material, is a simple planar structure with the advantage of simple structure. However, with the increase of the area of ​​industrial thin-film battery group, the stress between the functional film of the battery group and the substrate increases significantly, which is prone to defects such as substrate warping and deformation, film layer cracking and detachment.

[0004] All thin-film photovoltaic cells require a certain optical thickness for the light-absorbing layer to ensure effective absorption and utilization of irradiated light energy; at the same time, in order to reduce the recombination of carriers during their diffusion or drift and improve the photoelectric conversion efficiency, it is hoped that the movement distance of the carriers is short enough. Therefore, the opposite requirements are put forward for the physical thickness of the light-absorbing layer of thin-film cells.

[0005] 3. The biggest obstacle to the practical application of existing perovskite photovoltaic modules is the gap in stability compared with crystalline silicon photovoltaic modules, including thermal stability, light stability, and stability in water and oxygen environments. For example, some researchers believe that its decline mechanism has the following process:

[0006] ,

[0007] ,

[0008] ,

[0009]

[0010] Here the symbol " " is the symbol for reversible reaction, "s" represents solid, "aq" represents aqueous solution, "l" represents liquid, and "g" represents gas. The first three steps are all reversible reactions, except for the fourth step, which is under ultraviolet (UV) conditions. Because the product contains hydrogen, which can easily escape, the fourth step is actually an irreversible reaction. In other words, UV irradiation plays a key role in the decay of perovskite light-absorbing materials.

[0011] In order to take advantage of the wider band gap of perovskite materials to improve the efficiency of short-wave light utilization, the existing technology uses a perovskite cell group as the top cell and a crystalline silicon photovoltaic cell group with a smaller band gap as the bottom cell. The top cell absorbs the short-wave component of sunlight, and the bottom cell absorbs the long-wave component of sunlight that the top cell group cannot absorb and passes through the top cell. The two work together to achieve the overall purpose of improving the photoelectric conversion efficiency of the stacked photovoltaic module.

[0012] However, the result of doing so is that the perovskite battery group located at the top cell position will inevitably receive more UV radiation, greatly reducing the service life of the perovskite battery group. An analysis pointed out that "at present, the longest continuous illumination experiment of perovskite cells reaches 10,000 hours. If calculated based on the average sunshine duration of 4 hours throughout the day, the theoretical life is only 6.8 years. This is a big gap compared to the current theoretical life of crystalline silicon cells of 25 years." In other words, the life value of perovskite photovoltaic modules in the sunlight environment of the "top cell" does not match that of crystalline silicon photovoltaic modules, thereby reducing the expected life of the entire stacked photovoltaic module and the expected total power generation during its life.

[0013] 4. In the existing perovskite battery technology, lead is almost an indispensable element. Although the same family element tin can replace lead, due to the tin ion The redox potential is only +0.15V, which is lower than that of lead ions. At a redox potential of +1.67V, tin ions are more easily oxidized, and the stability and life of perovskite cells that completely replace lead with metallic tin will be worse. Therefore, currently practical perovskite photovoltaic cells that perform well in terms of stability all contain lead. In the prior art, in order to improve the stability of perovskite photovoltaic cells, the perovskite cell layer is prepared on the surface of the inner layer of the encapsulated conductive glass, which means that when the photovoltaic modules in use are damaged, there is a risk of environmental lead pollution.

[0014] The present invention is proposed to solve the problems existing in the prior art. It should be noted that some contents of the present invention only provide background technology related to the present invention and do not necessarily constitute prior art or known technology. Summary of the invention

[0015] Nouns and terms:

[0016] For the convenience of description, this application document defines the following nouns and terms:

[0017] 1) Photovoltaic cells:

[0018] Also known as a single photovoltaic cell, the most basic photovoltaic device, commonly known as a solar cell.

[0019] 2) Photovoltaic battery pack:

[0020] A photoelectric conversion unit is formed by connecting multiple photovoltaic cells in series and in parallel via electrodes.

[0021] 3) The "front" and "back" of photovoltaic modules:

[0022] The front side of a photovoltaic module refers to the side of the photovoltaic module designed to face more light radiation during use; the back side of a photovoltaic module refers to the side of the photovoltaic module designed to face less light radiation during use.

[0023] 4) The “main light-receiving surface” of the photovoltaic cell group:

[0024] Under the same irradiance, the photovoltaic cell group can output more electrical power on the light-receiving surface. In the present invention, the "main light-receiving surface" of the thin-film photovoltaic cell group is consistent with the side where the electrode layer with higher light transmittance is located.

[0025] 5) Front photovoltaic cell group:

[0026] A photovoltaic cell group whose main light-receiving surface is consistent with the front surface of the photovoltaic module.

[0027] 6) Back photovoltaic cell group:

[0028] A photovoltaic cell group whose main light-receiving surface is consistent with the back of the photovoltaic module.

[0029] 7) Photovoltaic modules:

[0030] Complete and environmentally friendly photovoltaic cell array package.

[0031] 8) Bifacial photovoltaic modules:

[0032] Photovoltaic modules can receive sunlight on both the front and back sides to generate electricity.

[0033] 9) Battery Dead Zone:

[0034] An area in a photovoltaic cell that contributes little to the photovoltaic power output and may even consume part of the output power.

[0035] 10) Thin-film battery light absorption layer:

[0036] The area in a thin film battery that absorbs light energy and excites carrier electrons and carrier holes.

[0037] 11) First charge transport layer:

[0038] A functional layer that absorbs the first carriers generated in the light absorption layer of a thin-film battery and blocks the second carriers, such as the p-type layer or n-type layer of a pn junction thin-film battery, or the p-type layer or n-type layer of a pin structure thin-film battery.

[0039] 12) Second charge transport layer:

[0040] A functional layer that absorbs the second carriers generated in the light absorption layer of a thin-film battery and blocks the first carriers, such as the n-type layer or p-type layer of a pn-junction thin-film battery, or the n-type layer or p-type layer of a pin-structure thin-film battery.

[0041] In a battery with a pn junction thin film structure, the p layer or n layer is both the thin film battery light absorption layer and the first or second charge transport layer respectively; in a battery with a pin thin film structure, the i layer is the main thin film battery light absorption layer, and the p layer or n layer is the first or second charge transport layer respectively.

[0042] 13) Horizontal diameter:

[0043] The horizontal diameter of a plane figure refers to the distance between the two intersection points where a straight line passing through the center of gravity of the plane figure intersects with the figure contour line and spans the figure of interest.

[0044] 14) Deposition:

[0045] Deposition and consolidation. The process methods for preparing the film layer of thin-film batteries, such as printing, sputtering, evaporation, atomic deposition, etc., have less lateral expansion and the resolution meets the graphic requirements.

[0046] Purpose and content of the invention:

[0047] The purpose of the present invention is to avoid mechanical damage and thermal damage when the single solar cells of a photovoltaic battery group are divided, thereby forming a dead zone, affecting the photoelectric conversion efficiency of the photovoltaic battery group and avoiding the mismatch between the life value of the perovskite photovoltaic module and the crystalline silicon photovoltaic module in the photovoltaic module, thereby reducing its expected life and the expected total power generation during the life.

[0048] The content of the present invention includes: in the first aspect, the present invention provides an integrated thin-film photovoltaic battery group, including a substrate, a first electrode layer, a photovoltaic functional layer including a first charge transport layer and a second charge transport layer, and a second electrode layer. The first surface of the substrate has a series groove, and the series groove has a mask wall B. The angle α between the mask wall B and the substrate reference plane A is in the range of 45° to 90°. In the z direction of the substrate, the depth of the mask wall B is greater than the sum of the thickness of the first electrode layer and the photovoltaic functional layer not including the second charge transport layer and is less than the total thickness of the first electrode layer, the photovoltaic functional layer, and the second electrode layer. The first electrode layer, the photovoltaic functional layer including the first charge transport layer and the second charge transport layer, and the second electrode layer are sequentially prepared on the projection surface of the xy plane of the first surface of the substrate. Each monomer thin-film photovoltaic cell is formed by means of the series groove. The integrated thin-film photovoltaic battery group is formed by connecting the first electrode layer of the monomer thin-film photovoltaic cell in series with the second electrode layer of the adjacent monomer thin-film photovoltaic cell.

[0049] See attached Figure 1 The reason why the depth of the mask B is set to be greater than the sum of the thicknesses of the first electrode layer and the photovoltaic functional layer excluding the second charge transport layer is to reduce the leakage current of the battery and prevent the second electrode layer from directly contacting the light absorption layer, the second charge transport layer and the second electrode layer of the adjacent single cell, or prevent the first electrode layer from directly contacting the light absorption layer, the first charge transport layer and the first electrode layer of the adjacent single cell; at the same time, in order to complete the series connection between the single cells, the second electrode layer must cross the mask B to achieve connection with the first electrode layer of the adjacent single cell.

[0050] In some preferred embodiments, the integrated thin-film photovoltaic cell group is a perovskite integrated thin-film photovoltaic cell group.

[0051] Preferably, the substrate is a polymer substrate with a thickness of 20 μm to 300 μm.

[0052] Preferably, on the first surface of the substrate, there is a buffer protrusion and / or a buffer pit on the surface outside the series groove, the ratio of the minimum transverse diameter of the bottom plane of the buffer protrusion to the vertical height of the buffer protrusion and the ratio of the minimum transverse diameter of the opening upper plane of the buffer pit to the vertical depth of the buffer pit are less than 2.5, and on the surface of the buffer protrusion and / or the buffer pit on the first surface of the substrate, the first electrode layer, the photovoltaic functional layer, and the second electrode layer are sequentially prepared. The vertical height refers to the distance between the bottom plane of the buffer protrusion and the highest point of the surface of the buffer protrusion, and the vertical depth refers to the distance between the opening upper plane of the buffer pit and the lowest point of the surface of the buffer pit.

[0053] Preferably, the vertical height of the buffer protrusion and the vertical depth of the buffer pit are 100 μm to 450 μm.

[0054] Preferably, the vertical height of the buffer protrusion and the vertical depth of the buffer pit are 10 μm to 100 μm, excluding 100 μm.

[0055] Preferably, the material of the first electrode layer of the perovskite integrated thin-film photovoltaic cell group close to the substrate is a metal conductor material, and the material of the second electrode layer is a transparent conductor material.

[0056] In a second aspect, the present invention provides a method for preparing the integrated thin-film photovoltaic battery group according to the first aspect, comprising:

[0057] P1) preparing a series of grooves on the first surface of the substrate, and the method for preparing the series of grooves is not limited, for example, the grooves can be obtained by extrusion or removal processing;

[0058] P2) depositing a first electrode layer on the first surface of the substrate along the z direction to obtain individual photovoltaic cell regions divided by the series grooves, for example, by evaporation, sputtering, printing, etc.;

[0059] P3) on the first electrode layer of each single photovoltaic cell region, sequentially depositing each layer of the photovoltaic functional layer along the z direction, for example, by a printing method;

[0060] P4) Depositing a second electrode layer on the photovoltaic functional layer along the z direction, for example, by evaporation, sputtering, printing, etc.

[0061] In some preferred embodiments, the method for preparing the integrated thin-film photovoltaic battery group further includes one of the following features:

[0062] Feature 1: In step P1), the buffer protrusions and / or buffer pits are prepared on the first surface of the substrate;

[0063] Feature 2: In step P2), the first electrode layer deposited along the z-direction on the first surface of the substrate is an opaque metal electrode or a carbon electrode.

[0064] In a third aspect, the present invention provides a double-sided photovoltaic module, which includes, from the front to the back of the double-sided photovoltaic module, a transparent packaging front plate, a front photovoltaic cell group composed of more than 6 crystalline silicon photovoltaic cells, and a transparent packaging back plate, wherein the main light-receiving surface of the front photovoltaic cell group faces the transparent packaging front plate, and there is a back photovoltaic cell group between the front photovoltaic cell group and the transparent packaging back plate, the back photovoltaic cell group is a perovskite integrated thin-film photovoltaic cell group, the optical band gap of the light absorption material of each single photovoltaic cell in the perovskite integrated thin-film photovoltaic cell group is 1.45ev~1.65ev, and the main light-receiving surface of the back photovoltaic cell group faces the transparent packaging back plate.

[0065] In some preferred embodiments, the perovskite integrated thin-film photovoltaic battery group is the perovskite integrated thin-film photovoltaic battery group described in the first aspect or the perovskite integrated thin-film photovoltaic battery group prepared by the preparation method described in the second aspect.

[0066] Preferably, the transparent encapsulation front plate is glass, and the transparent encapsulation back plate is one of the following materials or structures:

[0067] 1) Glass;

[0068] 2) Using the glass substrate of the perovskite integrated thin-film photovoltaic battery group as a transparent packaging backplane;

[0069] 3) The transparent polymer substrate of the perovskite integrated thin-film photovoltaic battery group also serves as a transparent packaging backplane.

[0070] In a fourth aspect, the present invention provides a method for preparing the bifacial photovoltaic module according to the third aspect, comprising:

[0071] M1) Place the main light-receiving surface of the crystalline silicon photovoltaic cell group toward the transparent packaging front plate;

[0072] M2) placing the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group toward the transparent packaging backplane;

[0073] M3) stacking a transparent packaging backplane on the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group;

[0074] M4) The transparent encapsulation front plate and the crystalline silicon photovoltaic cell group, the crystalline silicon photovoltaic cell group and the perovskite integrated thin-film photovoltaic cell group, and the perovskite integrated thin-film photovoltaic cell group and the transparent encapsulation back plate are separated by encapsulation film, leads are led out, and heat-sealed and laminated to form the double-sided photovoltaic module.

[0075] The present invention has the following beneficial effects:

[0076] First, in the integrated thin-film photovoltaic battery group provided by the present invention, the first surface of the substrate has a series groove, the series groove has a mask wall B, the first electrode layer, the photovoltaic functional layer including the first charge transport layer and the second charge transport layer, and the second electrode layer are sequentially prepared on the bottom of the series groove on the first surface of the substrate and the surface outside the series groove. By means of the mask wall B which is at an angle of 45° to 90° with the substrate reference plane A when the first electrode layer is deposited along the z direction, the first electrode layer is segmented, and the height difference at both ends of the segmentation line is formed, which lays a foundation for segmenting the single cell;

[0077] By means of the design that the depth of the mask B in the z direction is greater than the sum of the thicknesses of the first electrode layer and the photovoltaic functional layer excluding the second charge transport layer, and less than the total thickness of the first electrode layer, the photovoltaic functional layer, and the second electrode layer, the leakage current of the battery can be reduced, and the direct contact between the second electrode layer and the light absorption layer, the second charge transport layer, and the second electrode layer of the adjacent single cell can be prevented, or the direct contact between the first electrode layer and the light absorption layer, the first charge transport layer, and the first electrode layer of the adjacent single cell can be prevented; and the second electrode of a single photovoltaic cell is connected to the first electrode of an adjacent single photovoltaic cell, thereby completing the series connection between the single photovoltaic cells.

[0078] Combined with the existing film deposition process, the arrangement of the series grooves of the present invention can form effective isolation and series connection between single photovoltaic cells. Each single photovoltaic cell is naturally spaced by means of a mask wall B at an angle of 45° to 90° with the substrate reference plane A. It is not necessary to form the interval between each single photovoltaic cell by means of a cutting process, which can eliminate the "dead zone" and thermal deformation of the battery pack caused by the laser grooving process, and can improve the photoelectric conversion efficiency of the integrated thin-film photovoltaic battery pack. The present invention sequentially prepares the first electrode layer, the photovoltaic functional layer, and the second electrode layer on the bottom of the series groove and the surface outside the series groove. The photovoltaic functional layer of each single photovoltaic cell is continuously arranged on the substrate. The width of the photovoltaic functional layer of the single cell on the substrate in the x direction will not be reduced due to the isolation and series connection between the single photovoltaic cells, but will increase, which can increase the light absorption efficiency.

[0079] Second: by setting a buffer protrusion or buffer pit on the surface outside the series groove and making the ratio of the minimum horizontal diameter of the bottom plane of the buffer protrusion to the vertical height of the buffer protrusion or the ratio of the minimum horizontal diameter of the upper plane of the opening of the buffer pit to the vertical depth of the buffer pit less than 2.5, it is more conducive to eliminating the mechanical stress and thermal stress between the substrate substrate and the battery film, and preventing defects such as substrate warping and deformation, and battery film layer cracking and detachment. The repeated reflection of the incident irradiation light on the side of the buffer pit or protrusion increases the average optical path length of the incident light in the battery light absorption layer without increasing the thickness of the thin-film battery light absorption layer, and improves the absorption of the incident light, or on the premise of fully absorbing and utilizing the irradiation light energy, the thickness of the photovoltaic functional layer can be thinned, the recombination of carriers in the light absorption area can be reduced, and the photoelectric conversion efficiency of the integrated thin-film photovoltaic battery group can be improved.

[0080] Third: In some preferred embodiments, the second electrode layer of the perovskite thin-film photovoltaic cell group is a transparent conductor material, and the first electrode layer is a metal conductor material. The incident light is irradiated to the photovoltaic functional layer on the bottom of the series groove, and after absorbing part of it, it is reflected by the opaque first electrode layer to form reflected light. Since the mask wall B is at an angle of 45° to 90° with the substrate reference plane A, the series groove extends to the lower part of the opaque second electrode layer of the adjacent single photovoltaic cell. The aforementioned reflected light is divided into at least two parts, one part enters the photovoltaic functional layer of the adjacent single photovoltaic cell, and the other part passes through the transparent polymer substrate, is reflected by the opaque first electrode layer of the adjacent single photovoltaic cell, and is incident on the photovoltaic functional layer on the bottom of the series groove again. Through the above two parts of reflected light, especially with the help of multiple reflections between the series groove wall B and the electrode metal, the light absorption at the division of the single photovoltaic cell is improved and increased, which is more conducive to the absorption of the incident light irradiated to the bottom of the series groove, thereby improving the light conversion efficiency. The present invention forms isolation and series connection between single photovoltaic cells by connecting grooves in series, which not only does not generate dead zones, but also effectively reflects the incident light irradiated to the bottom of the grooves in series before being incident on the light absorption zone, thereby reducing the thickness of the light absorption layer, reducing the recombination of carriers in the light absorption zone, and improving the photoelectric conversion efficiency of the integrated thin-film photovoltaic battery group.

[0081] Fourth: The double-sided photovoltaic module of the present invention places the perovskite thin-film photovoltaic cell group on the back of the double-sided photovoltaic module with its main light-receiving surface facing the transparent packaging backplane, collecting the reflected light and scattered light on the back of the double-sided photovoltaic module, so that the UV radiation received by the perovskite thin-film photovoltaic cell group during use is only about 10% of that on the front crystalline silicon photovoltaic cell group, which can increase the service life of the perovskite thin-film photovoltaic cell group by ten times, so that its service life can match that of the crystalline silicon photovoltaic cell group.

[0082] The present invention adjusts the optical band gap of the light absorption material of the perovskite integrated thin-film photovoltaic cell group to 1.45ev~1.65ev based on the spectral characteristics of the reflected light and scattered light on the back of the photovoltaic module, thereby maximizing its photoelectric conversion efficiency. At the same time, with the help of the first electrode layer of the metal conductor material, the infrared radiation that cannot be used by the perovskite integrated thin-film photovoltaic cell group is reflected out of the double-sided photovoltaic module, which is beneficial to reducing the operating temperature of the photovoltaic module.

[0083] The perovskite thin-film photovoltaic cell group of the present invention has a high photoelectric conversion efficiency due to the natural spacing between the individual photovoltaic cells, and can maintain sufficient power output even if it receives less light. The double-sided photovoltaic module of the present invention can introduce the perovskite thin-film photovoltaic cell group into the practical stage in advance, which helps to promote the rapid development of this low-cost photovoltaic cell.

[0084] Fifth, in the double-sided photovoltaic module of the present invention, the perovskite thin-film photovoltaic cell group is not directly prepared on the transparent packaging backplane. When the packaging backplane is a glass backplane, etc., when the packaging backplane is broken, the lead contained in its photovoltaic functional layer will not leak immediately to cause environmental pollution. As long as timely monitoring, replacement and recycling are carried out, it will not become an environmental problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0086] Figure 1 This is a schematic diagram of the structure of an integrated thin-film photovoltaic battery group according to Example 1 of the present invention.

[0087] Figure 2 This is a schematic diagram of the structure of the series-connected slot-outer structure of the integrated thin-film photovoltaic battery group according to Example 1 of the present invention.

[0088] Figure 3 This is a schematic diagram of a double-sided photovoltaic module containing a crystalline silicon photovoltaic cell group and a perovskite thin film photovoltaic cell group according to Example 2 of the present invention.

[0089] Figure 4 It is a schematic diagram of the structure of a prior art perovskite integrated thin-film photovoltaic battery group.

[0090] Description of reference numerals:

[0091] 1-substrate; 2-first electrode layer; 3-photovoltaic functional layer; 31-first charge transport layer; 32-light absorption layer; 33-second charge transport layer; 4-second electrode layer; 5-series groove; 6-transparent encapsulation front plate; 61-module front; 7-transparent encapsulation back plate; 71-module back; 8-front photovoltaic cell group; 9-back photovoltaic cell group. DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0093] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0094] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0095] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0096] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0097] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0098] Example 1

[0099] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides an integrated thin-film photovoltaic battery group, including a substrate 1, a first electrode layer 2, a photovoltaic functional layer 3, and a second electrode layer 4, and has the following two characteristics:

[0100] 1) If Figure 1 As shown, a series groove 5 is prepared on the first surface of the substrate 1, and the series groove 5 has a mask wall B. The angle α between the mask wall B and the substrate reference plane A is 75°. The depth of the mask wall B in the z direction of the substrate is greater than the sum of the thicknesses of the first electrode layer 2 and the photovoltaic functional layer 3 not including the second charge transport layer 33, and is less than the total thickness of the first electrode layer 2, the photovoltaic functional layer 3, and the second electrode layer 4. The first electrode layer 2, the photovoltaic functional layer 3 including the first charge transport layer 31 and the second charge transport layer 33, and the second electrode layer 4 are sequentially prepared on the bottom of the series groove 5 on the first surface of the substrate 1 and the surface outside the series groove 5. A single photovoltaic cell is formed between the two series grooves 5. The first electrode layer 2 of the single photovoltaic cell and the second electrode layer 4 of the adjacent single photovoltaic cell are connected in series to form the integrated thin-film photovoltaic cell group.

[0101] 2) A buffer pit is prepared on the surface outside the series groove 5 on the first surface of the substrate 1, and the vertical depth of the buffer pit is 100 μm. The ratio of the minimum horizontal diameter of the upper plane of the opening of the buffer pit to the vertical depth of the buffer pit is 1. The first electrode layer 2, the photovoltaic functional layer 3, and the second electrode layer 4 are sequentially prepared on the surface of the buffer pit on the first surface of the substrate 1 to divide it into multiple single photovoltaic cells. The integrated thin-film photovoltaic cell group is formed by connecting the first electrode layer 2 of the single photovoltaic cell in series with the second electrode layer 4 of the adjacent single photovoltaic cell.

[0102] The integrated thin-film photovoltaic battery group of this embodiment is a perovskite integrated thin-film photovoltaic battery group, and its photovoltaic functional layer 3 is composed of a first charge transport layer 31 , a light absorption layer 32 , and a second charge transport layer 33 .

[0103] The layers of the perovskite integrated thin-film photovoltaic battery group of this embodiment are composed of: substrate 1: glass fiber reinforced PET, first electrode layer 2: metal aluminum, first charge transport layer 31 (electron transport layer): PCBM, light absorption layer 32: , the second charge transport layer 33 (hole transport layer): PEDOT:PSS, the second electrode layer 4 (transparent conductive film layer): ytterbium fluoride-doped indium oxide transparent conductive film (IYFO).

[0104] The preparation method of embodiment 1:

[0105] The first electrode layer 2, metal aluminum, can be obtained by evaporation, sputtering, atomic deposition and other technical means, and the first electrode layer is divided by means of the mask wall B of the series groove 5;

[0106] The first charge transport layer 31, PCBM Obtained by means of slot coating technology;

[0107] The light absorbing layer 32, (Right now ), using the "slit coating" technology to coat in steps and MAI in situ reaction to obtain film;

[0108] The second charge transport layer 33, PEDOT:PSS, is obtained by means of a slot coating technique;

[0109] The second electrode layer 4, IYFO, is obtained by printing, atomic deposition and other technical means. With the help of the height of the mask wall B of the series groove 5, the second electrode layer 4 is connected to the first electrode layer 2 of the adjacent single photovoltaic cell. Each single photovoltaic cell is connected in sequence to form the perovskite integrated thin film photovoltaic cell group.

[0110] This embodiment has the following beneficial effects:

[0111] 1) With the help of the "series groove 5", effective isolation between single photovoltaic cells can be formed, which is better than the perovskite integrated thin film photovoltaic battery group in the prior art (reference Figure 4 ), reduce the "dead zone d" of the integrated thin-film photovoltaic battery group, and improve the photoelectric conversion efficiency of the integrated thin-film photovoltaic battery group;

[0112] 2) With the help of the "series groove 5", the process purpose of connecting the individual photovoltaic cells in series without cutting grooves is achieved;

[0113] 3) By means of the buffer pits on the surface outside the series groove 5 on the first surface of the substrate 1, the average optical path of the incident light in the battery light absorption layer 32 is increased, the absorption rate of the incident light is increased, and the photoelectric conversion efficiency of the perovskite integrated thin film photovoltaic battery group is improved;

[0114] 4) With the aid of the first electrode layer 2 of opaque metal aluminum, combined with the buffer pits on the surface outside the series grooves 5 on the first surface of the integrated thin-film photovoltaic cell group substrate, the incident light is effectively reflected multiple times before being incident on the light absorption layer 32. Therefore, the thickness of the light absorption layer 32 can be reduced, the recombination of carriers in the light absorption layer 32 can be reduced, and the photoelectric conversion efficiency of the integrated thin-film photovoltaic cell group can be improved.

[0115] Example 2

[0116] refer to Figure 1~Figure 3 The embodiment of the present invention provides a bifacial photovoltaic module, which includes a transparent encapsulation front plate 6 in the form of tempered glass, a front photovoltaic cell group 8 composed of more than 6 crystalline silicon photovoltaic cells, a back photovoltaic cell group 9, and a transparent encapsulation back plate 7 in the form of tempered glass, from the bifacial photovoltaic module, the front side 61 to the back side 71 of the module;

[0117] The back photovoltaic cell group 9 is the perovskite integrated thin-film photovoltaic cell group as described in Example 1, and the main light-receiving surface of the back photovoltaic cell group 9 faces the transparent packaging back plate 7. The front photovoltaic cell group 8 and the back photovoltaic cell group 9 of the bifacial photovoltaic module absorb and convert the light incident from the front and the light incident from the back of the photovoltaic module respectively.

[0118] The preparation method of embodiment 2:

[0119] Using the perovskite integrated thin-film photovoltaic battery group described in Example 1, the stacking sequence of the double-sided photovoltaic modules is as follows:

[0120] M1) placing the main light-receiving surface of the crystalline silicon photovoltaic cell group toward the transparent packaging front plate 6;

[0121] M2) placing the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group toward the transparent packaging backplane 7;

[0122] M3) stacking 7 layers of transparent packaging backplane on the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group;

[0123] M4) The transparent encapsulation front plate 6 and the crystalline silicon photovoltaic cell group, the crystalline silicon photovoltaic cell group and the perovskite integrated thin film photovoltaic cell group, and the perovskite integrated thin film photovoltaic cell group and the transparent encapsulation back plate 7 are separated by encapsulation film, the leads are led out, and the two-sided photovoltaic module is formed by heat sealing and lamination.

[0124] This embodiment has the following beneficial effects:

[0125] 1) From theoretical analysis, it can be seen that the decomposition of HI by UV is the main factor affecting the performance of perovskite materials. The key step of decay speed, controlling this step will extend the service life of perovskite cells. The bifacial photovoltaic module of this embodiment places the perovskite thin film photovoltaic cell group on the back of the bifacial photovoltaic module, back to back with the crystalline silicon photovoltaic cell group, collects the reflected light and scattered light on the back of the bifacial photovoltaic module, so that the perovskite thin film photovoltaic cell group on the back of the photovoltaic module receives only about 10% of the UV radiation of the crystalline silicon photovoltaic cell group on the front during its service life. Therefore, the service life of the perovskite thin film photovoltaic cell group is increased tenfold, so that its service life can match that of the crystalline silicon photovoltaic cell group, and the perovskite thin film photovoltaic cell group can be introduced into the practical stage as soon as possible, which will help promote the rapid development of this low-cost photovoltaic cell;

[0126] 2) In the present invention, the perovskite thin-film photovoltaic battery group is not directly prepared on the transparent packaging back plate 7 in the form of tempered glass. Therefore, when the transparent packaging back plate 7 is broken for some reason, the lead contained therein will not leak immediately to cause environmental pollution. As long as timely monitoring, replacement and recycling are carried out, it will not become an environmental problem.

[0127] In summary, the technical solution provided by the present invention has significant cost advantages and cost reduction potential, and is of great significance to the development of the industry.

[0128] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An integrated thin-film photovoltaic battery group, comprising a substrate, a first electrode layer, a photovoltaic functional layer including a first charge transport layer and a second charge transport layer, and a second electrode layer, characterized in that: The first surface of the substrate has a series groove, and the series groove has a mask wall B. The angle α between the mask wall B and the substrate reference plane A is in the range of 45°~90°. In the z direction of the substrate, the depth of the mask wall B is greater than the sum of the thickness of the first electrode layer and the photovoltaic functional layer excluding the second charge transport layer and is less than the total thickness of the first electrode layer, the photovoltaic functional layer, and the second electrode layer. The first electrode layer, the photovoltaic functional layer including the first charge transport layer and the second charge transport layer, and the second electrode layer are sequentially prepared on the projection surface of the xy plane of the first surface of the substrate. Each monomer thin film photovoltaic cell is formed by means of the series groove, and the integrated thin film photovoltaic cell group is formed by the first electrode layer of the monomer thin film photovoltaic cell and the second electrode layer of the adjacent monomer thin film photovoltaic cell connected in series.

2. The integrated thin-film photovoltaic battery group according to claim 1, characterized in that: The integrated thin-film photovoltaic battery group is a perovskite integrated thin-film photovoltaic battery group.

3. The integrated thin-film photovoltaic battery group according to claim 2, characterized in that: The substrate is a polymer substrate with a thickness of 20 μm to 300 μm.

4. The integrated thin-film photovoltaic battery group according to claim 3, characterized in that: On the first surface of the substrate, there are buffer protrusions and / or buffer pits on the surface outside the series grooves, and the ratio of the minimum transverse diameter of the bottom plane of the buffer protrusion to the vertical height of the buffer protrusion and the ratio of the minimum transverse diameter of the opening upper plane of the buffer pit to the vertical depth of the buffer pit are less than 2.

5. On the surface of the buffer protrusions and / or the buffer pits on the first surface of the substrate, the first electrode layer, the photovoltaic functional layer, and the second electrode layer are sequentially prepared.

5. The integrated thin-film photovoltaic battery group according to claim 4, characterized in that: The vertical height of the buffer protrusion and the vertical depth of the buffer pit are 100 μm to 450 μm.

6. The integrated thin-film photovoltaic battery group according to claim 4, characterized in that: A vertical height of the buffer protrusion and a vertical depth of the buffer pit are 10 μm to 100 μm, excluding 100 μm.

7. The integrated thin-film photovoltaic battery group according to claim 3, characterized in that: The material of the first electrode layer of the perovskite integrated thin-film photovoltaic cell group close to the substrate is a metal conductor material, and the material of the second electrode layer is a transparent conductor material.

8. A method for preparing an integrated thin-film photovoltaic battery group according to any one of claims 1 to 7, characterized in that: include: P1) preparing a series of grooves on the first surface of the substrate; P2) depositing a first electrode layer along the z direction on the first surface of the substrate to obtain individual photovoltaic cell regions divided by the series grooves; P3) on the first electrode layer of each single photovoltaic cell region, sequentially depositing each layer of the photovoltaic functional layer along the z direction; P4) Depositing a second electrode layer on the photovoltaic functional layer along the z direction.

9. The method for preparing an integrated thin-film photovoltaic battery group according to claim 8, characterized in that: The method for preparing the integrated thin-film photovoltaic battery group also includes one of the following features: Feature 1: In step P1), buffer protrusions and / or buffer pits are prepared on the first surface of the substrate; Feature 2: In step P2), the first electrode layer deposited along the z-direction on the first surface of the substrate is an opaque metal electrode or a carbon electrode.

10. A bifacial photovoltaic module, comprising, from the front to the back of the module, a transparent encapsulation front plate, a front photovoltaic cell group consisting of more than 6 crystalline silicon photovoltaic cells, and a transparent encapsulation back plate, wherein the main light-receiving surface of the front photovoltaic cell group faces the transparent encapsulation front plate, characterized in that: There is a back photovoltaic cell group between the front photovoltaic cell group and the transparent packaging backplane, the back photovoltaic cell group is a perovskite integrated thin-film photovoltaic cell group, the perovskite integrated thin-film photovoltaic cell group is the perovskite integrated thin-film photovoltaic cell group as described in any one of claims 2 to 7 or the perovskite integrated thin-film photovoltaic cell group prepared by the preparation method described in claim 8 or 9, the optical band gap of the light absorption material of each single photovoltaic cell in the perovskite integrated thin-film photovoltaic cell group is 1.45ev~1.65ev, and the main light-receiving surface of the back photovoltaic cell group faces the transparent packaging backplane.

11. The double-sided photovoltaic module according to claim 10, characterized in that: The transparent encapsulation front plate is glass, and the transparent encapsulation back plate is one of the following materials or structures: 1) Glass; 2) Using the glass substrate of the perovskite integrated thin-film photovoltaic battery group as a transparent packaging backplane; 3) The transparent polymer substrate of the perovskite integrated thin-film photovoltaic battery group also serves as a transparent packaging backplane.

12. A method for preparing a double-sided photovoltaic module according to claim 10 or 11, characterized in that: include: M1) Place the main light-receiving surface of the crystalline silicon photovoltaic cell group toward the transparent packaging front plate; M2) Place the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group toward the transparent packaging backplane; M3) stacking a transparent packaging backplane on the main light-receiving surface of the perovskite integrated thin-film photovoltaic cell group; M4) The transparent encapsulation front plate and the crystalline silicon photovoltaic cell group, the crystalline silicon photovoltaic cell group and the perovskite integrated thin-film photovoltaic cell group, and the perovskite integrated thin-film photovoltaic cell group and the transparent encapsulation back plate are separated by encapsulation film, leads are led out, and heat-sealed and laminated to form the double-sided photovoltaic module.

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