Thin-film solar module and its manufacturing method

Abstract

The bypass diode of each monolithic cell is formed on a substrate in the form of a thin film and adopts a structure similar to that of the monolithic cell, and each monolithic cell and the corresponding bypass diode share the same substrate, and the layer processing method for the thin film in the bypass diode region on the substrate is different from that for the cell region, and the compound materials or layer order adopted as layers of the thin film in the bypass diode region on the substrate are different from those in the cell region, so that the threshold voltage of the bypass diode is reduced.

Description

[Technical Field]

[0001] This application relates to the field of thin film photovoltaic cell technology, and more particularly to thin film photovoltaic solar modules and methods for manufacturing the same. [Background technology]

[0002] A solar module consists of monolithic solar cells connected in series, and a photovoltaic generator consists of solar modules connected in series. If some PV modules in a string of normally unshaded PV modules are shaded, reverse voltage can develop in the shaded modules, potentially damaging them. This can be prevented by bypass diodes operating in parallel with each PV module.

[0003] While bypass diodes provide protection when many cells are shaded, they cannot provide protection when only a few cells in a PV module are shaded, which can expose the individual shaded cells to potentially harmful reverse voltages.

[0004] It is economically and technically impossible to install a large number of conventional diodes (at most one diode per monolithic solar cell). Therefore, for monolithic thin-film modules, methods exist for converting part of the surface of the thin-film photovoltaic cell into a bypass diode during the manufacturing process to limit the maximum reverse voltage in the shade. A method for manufacturing such an integrated bypass diode is described in patent EP2005474B1. However, since the cell material is typically designed for use under illumination with a forward voltage, it is not practically suitable for use as a diode in the dark. Therefore, the high threshold voltage results in a large power loss in the diode. As a result, due to heat generation, the diode's cell surface must be very large relative to the solar cell surface, which, in turn, excessively reduces the module's power.

[0005] In the prior art, there are two methods for fabricating bypass diodes for thin-film photovoltaic cells: one is a conventional external diode with a low threshold voltage, and the other is the integrated bypass diode solution for monolithically connected thin-film modules described in European Patent EP2005474B1. Of the two methods, the first method is only suitable for cell strings within encapsulated solar modules due to the difficulty and manufacturing cost, while the integrated bypass diodes fabricated using the second method have a threshold voltage that is too high, resulting in high power loss.

[0006] Another possible solution is to apply a bypass diode above or below the material of the monolithic thin-film cell in a so-called tandem structure, a method described in many differently implemented patents (US000004759803A, US000005261969A, EP000001443566B1, WO00200006565A1, US000006452086B1, WO00200054926A2, US02000502275057A1, WO002006053518A1, US000009029685B2, EP000001914808B1, WO00200111295A2, and WO002013058724A2). However, these methods require a greater intervention in the manufacturing process and involve multiple additional steps, which, in addition to the technical problems of so-called tandem structures, make them economically impossible to integrate into industrial production.

[0007] This also applies to circuits integrated on monolithic thin film cell materials, such as those described in patent specifications WO002013075144A1 or EP000001605512A2, which are too large for practical production processes. Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above problems in the prior art, the present application provides a thin-film photovoltaic solar module and a manufacturing method thereof. The integrated bypass diodes manufactured by this method have diode characteristics with a low threshold voltage, which significantly reduces the reverse voltage when shaded, preventing potential damage to the cell material, reducing heat loss within the bypass diodes, reducing the area required for manufacturing the integrated bypass diodes on the solar module, and minimizing the loss of cell module area for power generation. The technical solutions of this application are as follows: [Means for solving the problem]

[0009] In a first aspect, there is provided a thin film photovoltaic cell with integrated bypass diodes, wherein the bypass diode of each monolithic cell is formed on a substrate in the form of a thin film and adopts a similar structure to that of the monolithic cell, each monolithic cell and its corresponding bypass diode share the same substrate, a layer processing method for the thin film in a bypass diode region on the substrate is different from a layer processing method for a cell region, and a compound material adopted as a layer of the thin film in the bypass diode region on the substrate is different from that in the cell region, such that a threshold voltage of the bypass diode is reduced.

[0010] In some embodiments, the layer includes, but is not limited to, an absorber layer and an additional layer for passivating grain boundary defects and lattice defects, and the layer processing method includes a deposition processing process and a thermal processing process for the layer, and the deposition processing process includes a PVD (Physical Vapor Deposition) coating process, thermal evaporation, and spraying.

[0011] In some embodiments, when layers in the cell region on the substrate are processed, the layer processing in the cell region and the layer processing in the bypass diode region are not performed simultaneously, and the bypass diode region is covered with a covering framework to prevent thin film compound materials applied in the cell region from penetrating into the bypass diode region.

[0012] In some embodiments, the covering framework is made of a ceramic material.

[0013] In some embodiments, for a monolithic thin film photovoltaic cell, the compound material employed as the absorber layer in the cell region comprises a chalcogen-containing chalcopyrite compound semiconductor, and the compound material employed as the absorber layer in the bypass diode region is a sulfur-free chalcopyrite compound semiconductor.

[0014] In some embodiments, for a monolithic thin film photovoltaic cell, the sulfur content in the compound material employed as the absorber layer in the bypass diode region is less than the sulfur content in the compound material employed as the absorber layer in the cell region.

[0015] In some embodiments, in the case of a monolithic thin-film photovoltaic cell, the absorber layer in the cell region and the absorber layer in the bypass diode region are processed separately when the absorber layer is processed, so that a compound material employed as an absorber layer in the cell region is prevented from penetrating into the bypass diode region, and the bypass diode region is covered with the covering framework when the absorber layer in the cell region is processed.

[0016] In some embodiments, the additional layer for passivating grain boundary and lattice defects comprises a PDT (Post Deposition Treatment) post-treatment layer applied to the surface of the absorber layer.

[0017] In some embodiments, for monolithic thin film photovoltaic cells, a PDT post-treatment layer is applied onto the surface of the absorber layer in the cell region, but not onto the surface of the absorber layer in the bypass diode region.

[0018] In some embodiments, for a monolithic thin film photovoltaic cell, the amount of compound material employed as a PDT post-treatment layer in the bypass diode region is less than the amount of compound material employed as a PDT post-treatment layer in the cell region.

[0019] In some embodiments, in the case of a monolithic thin-film photovoltaic cell, when the PDT post-treatment layer is processed, the PDT post-treatment layer in the cell region and the PDT post-treatment layer in the bypass diode region are processed separately, so that a compound material employed as the PDT post-treatment layer in the cell region is prevented from penetrating into the bypass diode region, and when the PDT post-treatment layer in the cell region is processed, the bypass diode region is covered with the covering framework.

[0020] In some embodiments, during heat treatment in the process of manufacturing a thin film photovoltaic cell, the cell region is locally heated by a localized annealing method (eg, localized laser pulse annealing).

[0021] In some embodiments, during heat treatment in the process of manufacturing the thin-film photovoltaic cell, the bypass diode region is covered with a covering framework structure to prevent an increase in sulfur content in the bypass diode region due to sulfur-containing gases used in the heat treatment process.

[0022] In some embodiments, an additional layer to layer processing method includes buffer layer deposition on a surface of the absorber layer where the bypass diode region is covered with the covering framework, such that deposition of the buffer layer in the bypass diode region is prevented.

[0023] In some embodiments, for series thin film photovoltaic cells: When the series thin-film photovoltaic module has a 4T structure, it is composed of a plurality of thin-film photovoltaic modules arranged one above the other, with at least one thin-film photovoltaic module having the integrated bypass diode; When the series thin-film photovoltaic module is a 2T or 3T structure, the series thin-film photovoltaic cells include a top cell and a bottom cell, and the bypass diode region of the bottom cell is covered with the covering frame structure to prevent deposition of the top cell in the bypass diode region.

[0024] In some embodiments, the covering framework is combined with a carrier for supporting the substrate in the layer deposition treatment process and a process cover plate in the thermal treatment process.

[0025] In a second aspect, a method for making the thin film photovoltaic solar module having one or more integrated bypass diodes includes: providing a substrate with a suitable multi-part cladding framework; combining the substrate with part or all of the covering framework so that the covering framework covers a portion of the surface of the substrate; introducing the substrate into a processing chamber to coat the surface portion of the substrate exposed by the covering framework.

[0026] In some embodiments, the step of providing a suitable multi-part coated framework for the substrate further comprises providing a carrier for supporting the substrate during the layer deposition treatment process and / or a process cover plate during the thermal treatment process. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic diagram showing the location of bypass diode regions on a thin film photovoltaic module. [Figure 2] FIG. 1 is a schematic diagram illustrating a method for covering a bypass diode region on a thin-film photovoltaic module with a covering frame structure. [Figure 3] 10 is a schematic diagram showing a combined use of a cover frame structure and a movable process cover plate. FIG. [Figure 4] 10 is a schematic diagram showing another method of using a combination of a covering frame structure and a movable process cover plate. FIG. [Figure 5] FIG. 10 is a schematic diagram showing how an additional seal can be used in combination with a cover frame structure and a movable process cover plate. [Figure 6] 10 is a schematic diagram showing the combined use of a covering frame structure and a fixed process cover plate. FIG. [Figure 7] 1 is a graph showing current / voltage (IV) curves of a CIGS solar cell at varying illuminance. [Figure 8] 1 is a graph showing the IV curve of a series connection of 20 fully illuminated solar cells and one half-shaded solar cell. The dashed line indicates the operating current (maximum power point). [Figure 9] IV characteristic curve of a single monolithic solar cell without a bypass diode, with the dashed box area being the potentially harmful operating region. [Figure 10] FIG. 1 is an overall IV characteristic curve of an illuminated single monolithic solar cell connected in parallel with a shaded bypass diode of similar cell material. [Figure 11] 1 is a full IV characteristic curve of an illuminated single monolithic solar cell connected in parallel with a shaded bypass diode after the threshold voltage of the bypass diode has been reduced. DETAILED DESCRIPTION OF THE INVENTION

[0028] According to existing technology, in the manufacturing process of thin-film modules, there are different methods for increasing the open circuit voltage of solar modules under illumination in different thin-film technologies. These methods are mainly used to increase the efficiency of solar modules, but they also cause an undesirable increase in the threshold voltage Us when the solar cell operates as a diode in the absence of illumination, for example in the case of integrated bypass diodes.

[0029] Essentially, these methods for increasing the open circuit voltage Voc reduce the saturation current density of the diode, where the bandgap of the material system is increased by incorporating other elements / substances into the semiconductor material matrix, or where the recombination losses of generated charge carriers are minimized by passivating defects, crystalline imperfections and grain boundaries within the semiconductor bulk material or at the interfaces of adjacent layers of the semiconductor material matrix or solar cell structure.

[0030] The present application provides a thin-film photovoltaic cell having one or more integrated bypass diodes, wherein the bypass diode of each monolithic cell is formed on a substrate in the form of a thin film and adopts a structure similar to that of the monolithic cell, and each monolithic cell and its corresponding bypass diode share the same substrate, and a layer processing method for the thin film in a bypass diode region on the substrate is different from that for the cell region, and a compound material adopted as a layer of the thin film in the bypass diode region on the substrate is different from that in the cell region, so that the threshold voltage of the bypass diode is reduced.

[0031] With reference to the solar cell module disclosed in PCT / EP2007 / 053450, a method for manufacturing a bypass diode for a solar cell is disclosed, where the bypass diode area on a thin film photovoltaic cell is shown in Figure 1. The aim of this application is to prevent an increase in the bandgap of the material system or an increase in local recombination losses in the area where the integrated bypass diode is located.

[0032] Specifically, this is achieved by partially coating the integrated bypass diode region of the thin film photovoltaic cell, thereby avoiding the addition of additional elements / materials to the semiconductor matrix to increase the bandgap of the material system. When coating the integrated bypass diode region, the layer processing method for the thin film in the bypass diode region on the substrate is different from the layer processing method for the cell region, so that the layer processing process for the cell region does not affect the layer processing method for the thin film in the bypass diode region, and the layer processing for the bypass diode region may employ different processing methods or compound materials than the cell region.

[0033] In addition to partial coverage of a homogeneous material mixture, process control in which other elements in the semiconductor matrix are only locally mixed is also an alternative.

[0034] A similar procedure can be adopted for partial coating or application where additional interfacial layers to passivate defects, crystalline imperfections, grain boundaries, etc. are deposited within the solar cell stack.

[0035] Alternatively, for processes with additional temperature treatments, thermal budget process control may be applied only locally, for example by localized laser pulse annealing.

[0036] The present application can be applied to all thin-film technologies with integrated series connection of individual cells, such as thin-film silicon modules, chalcopyrite modules (CIS, CIGS, CIGSSe, CZTS, etc.), II-VI based modules (e.g. CdTe), organic or dye-sensitized modules, perovskite modules, etc. The present application can also be applied to all tandem technologies with integrated series connection, in particular different combinations of thin-film technologies, such as perovskite-CIGS tandems, CIGS-CIGS tandems, perovskite-perovskite tandems, etc.

[0037] Specifically, the layers include, but are not limited to, an absorber layer and an additional layer for passivating grain boundary defects and lattice defects. The layer processing method includes a deposition process and a thermal treatment process for the layer, and the deposition process includes a physical vapor deposition (PVD) coating process, thermal evaporation, and spraying. A thin-film photovoltaic cell sequentially includes a substrate, a back electrode layer, a layer structure (absorber layer and buffer layer), and a front electrode layer, and a post-treatment layer (PDT) may be formed on the top surface of the absorber layer. In this application, the bypass diode adopts a structure similar to that of the monolithic cell, and the bypass diode region also includes the various film layers described above. The deposition process for the buffer layer includes atomic layer deposition (ALD), ion layer gas reaction (ILGAR), spray pyrolysis, chemical vapor deposition (CVD), physical vapor deposition (PVD), sputtering, thermal evaporation, or electron beam evaporation. The deposition process for the post-treatment layer includes depositing at least one post-treatment material onto the absorber layer by thermal evaporation, wet chemical bath deposition, electron beam evaporation, sputtering, atomic layer deposition, or spray pyrolysis, and then heating the post-treatment layer to diffuse the post-treatment layer into the absorber layer.

[0038] In the present application, when layers in the cell region on the substrate are processed, the layer processing in the cell region and the layer processing in the bypass diode region are not performed simultaneously, and the bypass diode region is covered with a covering frame structure so as to prevent thin film compound materials applied in the cell region from penetrating into the bypass diode region.

[0039] In an embodiment of the present application, the bypass diode region on a thin-film photovoltaic cell is covered with a covering frame structure, which may be made of a ceramic material. FIG. 1 is a schematic diagram showing the location of the bypass diode region in a plan view of a thin-film photovoltaic cell. For the bypass diode region shown in FIG. 1, a method of covering the bypass diode region shown in FIG. 2 is adopted, in which a frame structure 1 is used to cover the bypass diode region. The frame structure 1 is an open structure so that the uncovered region of the coated substrate 3, i.e., the cell region on the substrate, is exposed, and the uncovered region of the coated substrate 3 can be subjected to layer processing.

[0040] In one embodiment, in the case of a monolithic thin-film photovoltaic cell, the compound material employed as the absorber layer in the cell region includes a chalcogen-containing chalcopyrite compound semiconductor, and the compound material employed as the absorber layer in the bypass diode region is a sulfur-free chalcopyrite compound semiconductor. In another embodiment, in the case of a monolithic thin-film photovoltaic cell, the compound material employed as the absorber layer in the bypass diode region has a lower sulfur content than the compound material employed as the absorber layer in the cell region. Specifically, the absorber layer in the cell region and the absorber layer in the bypass diode region are deposited using different compound materials, and the compound material employed as the absorber layer in the bypass diode region has a reduced sulfur content or is sulfur-free, thereby lowering the threshold voltage of the bypass diode region. It can be seen that in one embodiment, the absorber layer in the cell region employs a sulfur-containing copper indium gallium sulfur selenide material (Cu(In,Ga)(S,Se)2 material), and the absorber layer in the bypass diode region employs a sulfur-free copper indium gallium selenide material (Cu(In,Ga)Se2 material).

[0041] In the case of a monolithic thin-film photovoltaic cell, when the absorber layer is processed, the absorber layer in the cell region and the absorber layer in the bypass diode region are processed separately so that a compound material used as the absorber layer in the cell region is prevented from penetrating into the bypass diode region, and when the absorber layer in the cell region is processed, the bypass diode region is covered with the covering frame structure. In an embodiment of the present application, when the absorber layer in the cell region is formed, the bypass diode region is partially covered so that a compound material of the absorber layer in the cell region is prevented from penetrating into the bypass diode region, i.e., sulfur is prevented from penetrating into the bypass diode region.

[0042] The additional layer for passivating grain boundary defects and lattice defects includes a PDT post-treatment layer applied to the surface of the absorber layer. In an embodiment of the present application, the post-treatment layer is deposited on the upper surface of the absorber layer to passivate grain boundary defects and lattice defects. Compound materials employed as the post-treatment layer include metal chalcogenides, oxygen compounds of metal chalcogenides, and hydroxide compounds of metal chalcogenides (especially those in oxidation states IV or VI). Specifically, the deposition process for the post-treatment layer includes three steps. In the first step, at least one post-treatment material is deposited on the absorber layer by thermal evaporation, wet chemical bath deposition, electron beam evaporation, sputtering, atomic layer deposition, or spray pyrolysis. In the second step, the post-treatment material is diffused into the absorber layer by a heat treatment process. In the third step, after the post-treatment material has diffused into the absorber layer, the post-treatment material present on the surface of the absorber layer is removed from the surface of the absorber layer.

[0043] In one embodiment, for a monolithic thin-film photovoltaic cell, a PDT post-treatment layer is applied on the surface of the absorber layer in the cell region but not on the surface of the absorber layer in the bypass diode region. In another embodiment, for a monolithic thin-film photovoltaic cell, the amount of compound material employed as the PDT post-treatment layer in the bypass diode region is less than the amount of compound material employed as the PDT post-treatment layer in the cell region. In an embodiment of the present application, the surface of the absorber layer in the cell region is post-treated to form a PDT post-treatment layer, and no or little post-deposition treatment material compound is applied to the surface of the absorber layer in the bypass diode region to lower the threshold voltage of the bypass diode region.

[0044] In the case of a monolithic thin-film photovoltaic cell, when the PDT post-treatment layer is processed, the PDT post-treatment layer in the cell region and the PDT post-treatment layer in the bypass diode region are processed separately, so that a compound material employed as the PDT post-treatment layer in the cell region is prevented from penetrating into the bypass diode region, and when the PDT post-treatment layer in the cell region is processed, the bypass diode region is covered with the covering framework structure.

[0045] In an embodiment of the present application, after the bypass diode region is coated and the absorber layer in the cell region and the bypass diode region of the thin-film photovoltaic cell is formed, a PDT post-treatment layer is deposited on top of the absorber layer in the cell region, and the absorber layer in the bypass diode region is either not treated or is post-deposition treated with a small amount of compound material of the PDT post-treatment layer.

[0046] In one embodiment, the present application provides a thin-film photovoltaic cell with one or more integrated bypass diodes, in which the cell region is partially heated during a thermal treatment in a process for manufacturing the thin-film photovoltaic cell. Specifically, in this embodiment, a layer treatment method for the thin film in the bypass diode region on the substrate is different from a layer treatment method for the cell region and includes partially heating the cell region during multiple thermal treatment processes. For example, the cell region is only partially heated by a thermal treatment process performed in a process for depositing an absorber layer or during a post-deposition treatment performed on the absorber layer.

[0047] Furthermore, in the thin-film photovoltaic cell having one or more integrated bypass diodes provided herein, the bypass diode region is covered with a covering frame structure during heat treatment in the process of manufacturing the thin-film photovoltaic cell, to prevent an increase in the sulfur content of the bypass diode region due to sulfur-containing gases used in the heat treatment. Specifically, in an embodiment of the present application, the layer processing method for the thin film in the bypass diode region on the substrate is different from the layer processing method for the cell region and further includes covering the bypass diode region with a covering frame structure during multiple heat treatment processes. It can be seen that the heat treatment process is performed in a vacuum environment under a sulfur-containing atmosphere, and covering the bypass diode region with a covering frame structure prevents sulfur from penetrating into the bypass diode region during the heat treatment, thereby reducing the increase in sulfur content in the bypass diode region. For example, when the absorber layer is annealed by RTP (rapid thermal processing), the bypass diode region is covered with a covering frame structure to prevent an increase in the sulfur content in the absorber layer in the bypass diode region due to gases used in the annealing process.

[0048] The additional layer for passivating interface defects and reducing interface recombination includes a buffer layer applied on the surface of the absorber layer. In an embodiment of the present application, a buffer layer is deposited on the top surface of the absorber layer to passivate interface defects and reduce interface recombination. Compound materials employed as the buffer layer include Na, ZnS, ZnO, Znx Mg 1-x O, ZnO x S 1-x , Ga x O y CdS doped / alloyed with In x S y , In x S y The buffer layer is deposited on the absorber layer by thermal evaporation, wet chemical bath deposition, electron beam evaporation, sputtering, atomic layer deposition or spray pyrolysis.

[0049] Based on the above description of thin film photovoltaic cells with one or more integrated bypass diodes, it can be seen that there are two fabrication methods when applied to fabricating series thin film photovoltaic cells:

[0050] In the first fabrication method, when the series thin-film photovoltaic module is a 4T structure, it is composed of a plurality of electrically connected thin-film photovoltaic modules arranged one above the other, with at least one thin-film photovoltaic module provided with an integrated bypass diode; In the second fabrication method, when the series thin-film photovoltaic module is a 2T or 3T structure, the series thin-film photovoltaic cells include a top cell and a bottom cell, and the bypass diode region of the bottom cell is covered with a covering frame structure to prevent deposition of the top cell on the bypass diode region.

[0051] In an embodiment of the present application, in a four-terminal series thin-film photovoltaic module, the entire series structure includes a plurality of thin-film photovoltaic cells coated and electrically connected one on top of the other, and an integrated bypass diode is fabricated for at least one thin-film photovoltaic cell by the above-mentioned bypass diode fabrication method. Of course, each thin-film photovoltaic cell may be provided with the above-mentioned integrated bypass diode.

[0052] In the case of a two-terminal or three-terminal series thin-film photovoltaic module, in order to prevent deposition of the top cell layer in the bypass diode region in the thin-film photovoltaic cell at the bottom of the series structure, an integrated bypass diode is manufactured by covering the bottom cell with a covering frame using the above bypass diode manufacturing method.

[0053] According to the thin-film photovoltaic cell having one or more integrated bypass diodes provided by the present application, in the process of manufacturing the thin-film photovoltaic cell, the covering frame structure 1 for covering the bypass diode region is used in conjunction with other auxiliary structures in various processes. In the layer deposition process, if a carrier 4 for supporting a substrate is used, the covering frame structure 1 for covering the bypass diode region is used in combination with the carrier 4. In the heat treatment process, if a process cover plate 2 is used, the covering frame structure 1 for covering the bypass diode region is used in combination with the process cover plate 2. Specifically, for example, if a carrier for supporting and fixing a substrate is used in the layer structure deposition process, the combination of the carrier and the covering frame structure jointly performs the layer structure deposition process. For example, if a process cover plate disclosed in PCT / EP2009 / 003301 is used in the heat treatment process, the combination of the process cover plate and the covering frame structure jointly performs the heat treatment process. Specifically, taking the heat treatment process as an example, FIGS. 3 to 6 are schematic diagrams illustrating how the covering frame structure is used in combination with the carrier and the process cover plate. By employing the heat treatment process disclosed in PCT / EP2009 / 003301, the covering frame structure of the present application can be used not only when the process cover plate is movable, but also when the process cover plate is fixed. Figures 3 and 4 are schematic diagrams showing how the covering frame structure can be used in combination with a movable process cover plate. Figure 5 is a schematic diagram showing how the covering frame structure 1 and a movable process cover plate 2 can be used in combination with a seal 5 added to accommodate different thermal expansion coefficients. Figure 6 is a schematic diagram showing how the covering frame structure can be used in combination with a fixed process cover plate.

[0054] A method for manufacturing the above thin film photovoltaic cell having one or more integrated bypass diodes includes: (Step A1) providing a substrate with a suitable multi-part coated framework; (Step A2) combining the substrate with part or all of the covering framework so that the covering framework covers part of the surface of the substrate; (Step A3) introducing the substrate into a processing chamber and coating the surface portion of the substrate exposed by the covering framework.

[0055] Specifically, the step of providing a suitable multi-part covering frame structure for the substrate in step A1 further includes the step of providing a carrier for supporting the substrate in the layer deposition process and / or a process cover plate in the heat treatment process.

[0056] Specifically, a method for fabricating the above thin film photovoltaic cell having one or more integrated bypass diodes includes: (Step B1) providing a substrate with a suitable multi-part covering frame structure, and providing both the carrier and the process cover plate on the substrate as needed, so that the covering frame structure, carrier, and process cover plate are used in combination to perform a layer structure deposition process and multiple heat treatment processes for a thin film photovoltaic cell; (Step B2) covering the substrate with the covering frame structure provided in step B1 so that a part of the surface of the substrate is covered by the covering frame structure, specifically, so that a bypass diode region on the surface of the substrate is covered by the covering frame structure, and as needed, combining the carrier and the process cover plate provided in step B1 with the substrate and the covering frame structure according to the method of FIGS. 3 to 6; (Step B3) Introducing the substrate and covering frame structure combined in step B2 into a processing chamber and coating the portion of the surface of the substrate that is not covered by the covering frame structure, or introducing the substrate, covering frame structure, carrier and process cover plate combined in step B2 into the processing chamber and coating the portion of the surface of the substrate that is not covered by the covering frame structure.

[0057] The voltage-current characteristic curve of the bypass diode in the bypass diode region of the thin-film photovoltaic cell having one or more integrated bypass diodes manufactured by the above method is significantly optimized and improved, and the effects of the optimization are described in detail below.

[0058] Generally, as shown in Figure 7, the characteristic curves of monolithic CIGS solar cells are generally related to sunlight and temperature, and in particular, the reverse characteristics have a strong relationship with sunlight. As shown in Figure 8, even if only a small number of monolithic thin-film photovoltaic cells are half-shaded, it can cause the generation of reverse current (negative voltage). Without a bypass diode, the characteristic curve of a monolithic thin-film photovoltaic cell is shown in Figure 9. It can be seen that the reverse current (negative voltage) generated by the thin-film photovoltaic cell will damage the material of the monolithic thin-film photovoltaic cell.

[0059] In a thin-film photovoltaic cell with one or more integrated bypass diodes, where the bypass diodes are fabricated from similar or identical cell materials as the photovoltaic cell, the voltage-current characteristic curves for the thin-film photovoltaic cell with one or more integrated bypass diodes when the cell area is unshaded and the bypass diode area is shaded are shown in Figure 10. The shaded bypass diode area operates at a negative voltage, which is potentially harmful under high power consumption and heat dissipation.

[0060] When a thin-film photovoltaic cell having one or more integrated bypass diodes according to the present invention is employed, the voltage-current characteristic curve of the thin-film photovoltaic cell having one or more integrated bypass diodes is shown in FIG. 11 when the cell area is unshaded and the bypass diode area is shaded. The reduction in forward voltage in the bypass diode area significantly reduces the power consumption (negative voltage) in the critical area. Therefore, the bypass diode can be smaller in size or can withstand higher power, reducing the probability of material damage to the monolithic thin-film photovoltaic cell.

[0061] As shown in FIG. 11, under the condition that the size of the integrated bypass diode is reduced, the power consumption of the thin-film photovoltaic cell having one or more integrated bypass diodes according to the present invention is reduced from 1.3 W to 0.3 W under the condition of 1 A current (threshold voltage is reduced from 1 V to 0.15 V).

[0062] The present application is not limited to the specific embodiments described above, and various modifications made by those skilled in the art from the above ideas without any creative effort shall fall within the scope of protection of the present application. [Explanation of symbols]

[0063] 1 Covered frame structure 2 Process cover plates 3 Coated substrate 4. Career 5 Seals 1a Lower frame structure 1b Upper frame structure.

Claims

1. A thin-film photovoltaic module having one or more integrated bypass diodes, wherein the bypass diode of each monolithic cell is formed on a substrate in the form of a thin film and adopts a structure similar to that of the monolithic cell, and each monolithic cell and the corresponding bypass diode share the same substrate, and the layer processing method for the thin film in the bypass diode region on the substrate is different from that for the cell region, and the compound materials or layer order adopted as layers of the thin film in the bypass diode region on the substrate are different from those in the cell region, so that the threshold voltage of the bypass diode is reduced. A thin film photovoltaic module having one or more integrated bypass diodes.

2. The layer includes, but is not limited to, an absorber layer and an additional layer for passivating grain boundary defects and lattice defects, and the layer treatment method includes a deposition treatment process and a heat treatment process for the layer, and the deposition treatment process includes a PVD (Physical Vapor Deposition) coating process, thermal evaporation, and spraying.

10. The thin film photovoltaic module of claim 1 having one or more integrated bypass diodes.

3. When layers in the cell region on the substrate are processed, the layer processing in the cell region and the layer processing in the bypass diode region are not performed simultaneously, and the bypass diode region is covered with a covering frame structure to prevent thin film compound materials applied in the cell region from penetrating into the bypass diode region.

3. The thin film photovoltaic module of claim 2 having one or more integrated bypass diodes.

4. The covering frame structure is made of ceramic material.

3. The thin film photovoltaic module of claim 2 having one or more integrated bypass diodes.

5. In the case of a monolithic thin-film photovoltaic cell, the compound material employed as the absorber layer in the cell region comprises a chalcogen-containing chalcopyrite compound semiconductor, and the compound material employed as the absorber layer in the bypass diode region is a sulfur-free chalcopyrite compound semiconductor.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

6. In the case of a monolithic thin-film photovoltaic cell, the sulfur content in the compound material employed as the absorber layer in the bypass diode region is less than the sulfur content in the compound material employed as the absorber layer in the cell region.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

7. In the case of the monolithic thin-film photovoltaic cell, when the absorber layer is processed, the absorber layer in the cell region and the absorber layer in the bypass diode region are processed separately so that a compound material employed as the absorber layer in the cell region is prevented from penetrating into the bypass diode region, and when the absorber layer in the cell region is processed, the bypass diode region is covered with the covering frame structure.

7. A thin film photovoltaic module having one or more integrated bypass diodes according to claim 5 or 6.

8. The additional layer for passivating grain boundary defects and lattice defects comprises a PDT post-treatment layer applied onto the surface of the absorber layer.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

9. In the case of a monolithic thin film photovoltaic cell, the PDT post-treatment layer is applied onto the surface of the absorber layer in the cell region, but not onto the surface of the absorber layer in the bypass diode region.

9. The thin film photovoltaic module having one or more integrated bypass diodes of claim 8.

10. For monolithic thin film photovoltaic cells, the amount of compound material employed as a PDT post-treatment layer in the bypass diode region is less than the amount of compound material employed as a PDT post-treatment layer in the cell region.

9. The thin film photovoltaic module having one or more integrated bypass diodes of claim 8.

11. In the case of the monolithic thin-film photovoltaic cell, when the PDT post-treatment layer is processed, the PDT post-treatment layer in the cell region and the PDT post-treatment layer in the bypass diode region are processed separately so that a compound material employed as the PDT post-treatment layer in the cell region is prevented from penetrating into the bypass diode region, and when the PDT post-treatment layer in the cell region is processed, the bypass diode region is covered with the covering framework.

11. A thin film photovoltaic module having one or more integrated bypass diodes according to claim 9 or 10.

12. During the heat treatment in the process of manufacturing the thin film photovoltaic cell, the cell region is partially heated.

12. The thin film photovoltaic module having one or more integrated bypass diodes according to claim 11.

13. The bypass diode region is covered with the covering frame structure so as to prevent an increase in the sulfur content of the bypass diode region due to a sulfur-containing gas used in the heat treatment process during the heat treatment in the process of manufacturing the thin-film photovoltaic cell.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

14. An additional layer to layer processing method includes buffer layer deposition on the surface of the absorber layer where the bypass diode region is covered with the covering framework, so that buffer layer deposition in the bypass diode region is prevented.

3. The thin film photovoltaic module of claim 2 having one or more integrated bypass diodes.

15. For series thin film photovoltaic modules, When the series thin-film photovoltaic module is a 4T structure, it is composed of a plurality of electrically connected thin-film photovoltaic modules arranged one above the other, at least one thin-film photovoltaic module being provided with the integrated bypass diode; When the series thin-film photovoltaic module is a 2T or 3T structure, the series thin-film photovoltaic cells include a top cell and a bottom cell, and the bypass diode region of the bottom cell is covered with the covering frame structure to prevent deposition of the top cell layer in the bypass diode region.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

16. The covering frame structure is combined with a carrier for supporting the substrate in a layer deposition process and a process cover plate in the heat treatment process.

4. The thin film photovoltaic module of claim 3 having one or more integrated bypass diodes.

17. 1. A method for manufacturing a thin film photovoltaic module having one or more integrated bypass diodes, comprising: providing a substrate with a suitable multi-part cladding framework; combining the substrate with part or all of the covering framework so that the covering framework covers a portion of the surface of the substrate; introducing the substrate into a processing chamber to coat the surface portion of the substrate exposed by the covering framework; 1. A method for manufacturing a thin film photovoltaic module having one or more integrated bypass diodes, comprising:

18. The step of providing a suitable multi-part covering frame structure for the substrate further comprises providing a carrier for supporting the substrate in a layer deposition process and / or a process cover plate in a thermal treatment process.

20. The method of claim 17 for making a thin film photovoltaic module having one or more integrated bypass diodes.

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