Solar cell module, photovoltaic string and power generation system

Abstract

The invention provides a solar cell module, a photovoltaic string and a power generation system. The solar cell module includes a first substrate, a second substrate, and a plurality of cell modules. Each battery assembly includes a bypass diode and a battery. The cells of the solar cell assembly are connected in series and the bypass diodes are connected in series. The battery is located on the surface of the first substrate, and the bypass diode is located on the surface of the second substrate. The anode of the bypass diode is electrically connected with the cathode of the battery, and the cathode of the bypass diode is electrically connected with the anode of the battery. The battery comprises at least one sub-battery which is connected in series, and the bypass diode is used for bypassing the battery when the output current of any sub-battery is smaller than the set current. The solar cell module can be respectively provided with a bypass diode and a sub-cell, and then the bypass diode and the sub-cell are reversely connected in parallel. When the sub-cell is shielded, the shielded sub-cell is bypassed through the bypass diode, so that the sub-cell is prevented from being reversely biased by high voltage, and the safety of the solar cell module is further improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a solar cell module, photovoltaic string, and power generation system. Background Technology

[0002] With the energy crisis worsening, replacing fossil fuels with new energy sources has become a central theme of our time, leading to the rapid development of solar cells. Perovskite solar cells, with their advantages of high theoretical conversion efficiency, low manufacturing cost, and highly adjustable bandgap, have become the most promising third-generation solar cells for commercialization and are currently being used in ground-mounted power plants and building-integrated photovoltaics (BIPV).

[0003] To fabricate large-area, high-efficiency perovskite solar cells, it is typically necessary to connect sub-cells in series to create perovskite solar cell modules, reducing energy loss. However, in practical applications, solar cells may be shaded by other objects, causing the shaded cell strips to malfunction, resulting in a lower or even nonexistent photocurrent. In this case, to ensure power output, the cell strip will enter the reverse-biased region, where a high reverse-biased voltage is applied, leading to rapid cell degradation. Summary of the Invention

[0004] This application provides a solar cell module, photovoltaic string, and power generation system, which fabricates a bypass diode and a sub-cell on two substrates respectively, and connects the bypass diode and the sub-cell in reverse parallel. This bypasses the shaded sub-cell through the bypass diode when the sub-cell is shaded, preventing the sub-cell from being reverse biased by high voltage, thereby improving the safety of the solar cell module.

[0005] In a first aspect, this application provides a solar cell module. The solar cell module specifically includes a first substrate, a second substrate, and a plurality of battery modules. The first substrate and the second substrate are disposed opposite each other along the thickness direction of the solar cell module, and the plurality of battery modules are located between the first substrate and the second substrate. Each battery module includes a bypass diode and a battery. In the solar cell module, the batteries of the plurality of battery modules are connected in series, and the bypass diodes of the plurality of battery modules are connected in series. In each battery module, the battery is located on the surface of the first substrate facing the second substrate, and the bypass diode is located on the surface of the second substrate facing the first substrate. The positive terminal of the bypass diode is electrically connected to the negative terminal of the battery, and the negative terminal of the bypass diode is electrically connected to the positive terminal of the battery. The battery includes at least one sub-cell connected in series, and the bypass diode is used to bypass the battery when the output current of any sub-cell is less than a set current.

[0006] When one or more sub-cells in a solar cell are shaded, the output current of the shaded sub-cells drops sharply due to insufficient sunlight, or even stops outputting current altogether. Since the series circuit requires consistent current, the sub-cell connected in series with the shaded sub-cell generates excess current. This excess current is forcibly injected into the shaded sub-cell, causing it to be reverse-biased, i.e., subjected to a high reverse bias voltage. This can lead to a surge in sub-cell temperature, even breakdown, resulting in melting or fire and causing a safety hazard. In the solar cell module of this application, a bypass diode in each module is connected in reverse parallel with the cell. The bypass diode has a low turn-on voltage characteristic. When a sub-cell is reverse-biased, the bypass diode connected in reverse parallel with the cell containing that sub-cell conducts, bypassing the cell. In other words, the two cells connected in series with the cell are directly conducted by the bypass diode, preventing the cell from entering the high reverse bias voltage region, thereby improving the safety of the solar cell module. Furthermore, the sub-cell and bypass diode are mounted on two separate substrates, allowing for the separate fabrication of the sub-cell and bypass diode during the fabrication of the solar cell module. The fabrication processes of the two are independent and complementary, thus broadening the range of materials available for the solar cell module.

[0007] Since the battery as a whole is connected in reverse parallel with the bypass diode, regardless of whether the battery includes one or more sub-cells, once any one or more sub-cells of the battery are blocked, the bypass diode connected in reverse parallel with the battery can bypass the entire battery. In this way, the number of bypass diodes can be set according to actual needs.

[0008] In the specific battery assembly configuration, the sub-cell includes a first electrode, a first charge transport layer, a first light absorption layer, a second charge transport layer, and a second electrode, sequentially stacked along the thickness direction. The first electrode is located between the first substrate and the first charge transport layer. The bypass diode includes a first conductive layer, a first semiconductor layer, a second semiconductor layer, and a second conductive layer, sequentially stacked along the thickness direction. The first conductive layer is located between the first semiconductor layer and the second electrode. The first semiconductor layer is electrically connected to the first conductive layer, and the second semiconductor layer is electrically connected to the second conductive layer. The first conductive layer is electrically connected to the second electrode of the battery, and the second conductive layer is electrically connected to the second electrode of an adjacent battery. An encapsulation layer is provided between the second electrode and the first conductive layer. Thus, after the bypass diode and the sub-cell are fabricated independently, they can be fixed together using encapsulating adhesive.

[0009] In some possible embodiments, the sub-cell can be a PIN junction-based cell, where the first electrode is a transparent electrode (i.e., the bottom electrode), the first charge transport layer is a hole transport layer, the second charge transport layer is an electron transport layer, and the second electrode is a metal electrode or a transparent electrode (i.e., the top electrode). In other words, from the first substrate to the second substrate, the thin film in the sub-cell layer sequentially consists of a bottom electrode, a hole transport layer, a first light absorption layer, an electron transport layer, and a top electrode. In this case, the first semiconductor layer of the bypass diode is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer.

[0010] In some other possible embodiments, the sub-cell can be an NIP junction-based cell, i.e., the first electrode is a transparent electrode, the first charge transport layer is an electron transport layer, the second charge transport layer is a hole transport layer, and the second electrode is a transparent electrode. In other words, from the first substrate to the second substrate, the thin film in the sub-cell layer sequentially consists of a bottom electrode, an electron transport layer, a first light absorption layer, a hole transport layer, and a top electrode. In this case, the first semiconductor layer of the bypass diode is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

[0011] In some possible embodiments, the bypass diode further includes a first conductive portion connected to a second conductive layer. The aforementioned plurality of battery components include a first battery component, a second battery component, and a third battery component. The first battery component includes a first sub-cell and a first bypass diode; the second battery component includes a second sub-cell and a second bypass diode; and the third battery component includes a third sub-cell and a third bypass diode. Specifically, the connections between the first, second, and third battery components are as follows: the second electrode of the first sub-cell is connected to the first electrode of the second sub-cell; the second electrode of the second sub-cell is connected to the first electrode of the third sub-cell. The first conductive layer of the first bypass diode is connected to the second electrode of the first sub-cell through the first conductive portion of the second bypass diode. The second conductive layer of the second bypass diode is connected to the second electrode of the first sub-cell through the first conductive portion of the second bypass diode; the first conductive layer of the second bypass diode is connected to the second electrode of the second sub-cell through the first conductive portion of the third bypass diode; and the second conductive layer of the third bypass diode is connected to the second electrode of the second sub-cell through the first conductive portion of the third bypass diode. In this embodiment, the first conductive portion can simultaneously achieve electrical connection between the sub-cell and two adjacent bypass diodes, thereby simplifying the structure of the solar cell component and reducing manufacturing costs.

[0012] In some other possible embodiments, the bypass diode further includes a second conductive portion and a third conductive portion, through which the sub-cell and the bypass diode are electrically connected. The second conductive portion is connected to the first conductive layer, and the third conductive portion is connected to the second conductive layer. The aforementioned plurality of battery assemblies include a first battery assembly, a second battery assembly, and a third battery assembly. The first battery assembly includes a first sub-cell and a first bypass diode; the second battery assembly includes a second sub-cell and a second bypass diode; and the third battery assembly includes a third sub-cell and a third bypass diode. The connection between the first battery assembly, the second battery assembly, and the third battery assembly is specifically as follows: the second electrode of the first sub-cell is connected to the first electrode of the second sub-cell, and the second electrode of the second sub-cell is connected to the first electrode of the third sub-cell. The first conductive layer of the first bypass diode is connected to the second electrode of the first sub-cell through the second conductive portion of the first bypass diode. The first conductive layer of the second bypass diode is connected to the second electrode of the second sub-cell through the second conductive portion of the second bypass diode, and the second conductive layer of the second bypass diode is connected to the second electrode of the first sub-cell through the third conductive portion of the second bypass diode. The second conductive layer of the third bypass diode is connected to the second electrode of the second sub-cell through the third conductive portion of the third bypass diode.

[0013] In some possible embodiments, along the thickness direction of the solar cell module, the projection of the first conductive layer of the first bypass diode overlaps with the projection of the second electrode of the first sub-cell; the projection of the second conductive layer of the second bypass diode overlaps with the projection of the second electrode of the first sub-cell; and the projection of the first conductive layer of the second bypass diode overlaps with the projection of the second electrode of the second sub-cell. The projection of the second conductive layer of the third bypass diode overlaps with the projection of the second electrode of the second sub-cell. In this way, the extension direction of the first or second conductive portion can be parallel to the thickness direction, reducing the size of the conductive portion for easier manufacturing and cost savings.

[0014] In some possible embodiments, the projections of the first conductive layer, the first semiconductor layer, the second semiconductor layer, and the second conductive layer overlap along the thickness direction. Therefore, the first conductive layer and the first semiconductor layer, the first semiconductor layer and the second semiconductor layer, and the second semiconductor layer and the second conductive layer are all electrically connected through direct contact, without the need for other electrical connection structures, thereby simplifying the structure of the solar cell module.

[0015] In some possible embodiments, the forward voltage of the bypass diode is less than or equal to 2V.

[0016] In some possible embodiments, the sub-cell can be a double-junction cell. Specifically, between the second charge transport layer and the second electrode of the sub-cell, there is also a composite layer, a third charge transport layer, a second light absorption layer, and a fourth charge transport layer. The first and third charge transport layers are of the same type, as are the second and fourth charge transport layers. The first charge transport layer, the first light absorption layer, and the second charge transport layer form the bottom cell film structure, and the third charge transport layer, the second light absorption layer, and the fourth charge transport layer form the top cell film structure. The top and bottom cell structures are independent of each other. In practical applications, the top and bottom cell structures can absorb light of different wavelengths, thereby maximizing photon utilization and improving the photoelectric conversion efficiency of the solar cell module.

[0017] Secondly, this application also provides a photovoltaic string. The photovoltaic string includes multiple solar cell modules as described in the first aspect. The photovoltaic string of this application uses solar cell modules equipped with bypass diodes. When a sub-cell of the solar cell module is shaded, the bypass diodes can bypass the shaded sub-cell, thereby preventing the shaded sub-cell from being reverse-biased by high voltage, which would cause a temperature surge and breakdown, thus improving the safety of the photovoltaic string.

[0018] Thirdly, this application also provides a power generation system. The power generation system includes a photovoltaic string, a DC-DC converter, and an inverter, as described in the second aspect. The photovoltaic string is connected to the inverter via the DC-DC converter, which converts the DC power output from the photovoltaic string into voltage before outputting it to the inverter. The inverter converts the DC power output from the DC-DC converter into AC power before outputting it. The power generation system of this application uses photovoltaic strings with high safety performance, which can improve the stability of the power generation system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a power generation system provided in an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of a structure of an existing solar cell module.

[0021] Figure 3 This is a schematic diagram of a perovskite solar cell.

[0022] Figure 4 This is a schematic diagram of the first structure of a solar cell module according to an embodiment of this application.

[0023] Figure 5 for Figure 2 Current and voltage characteristics of solar cell modules.

[0024] Figure 6 for Figure 4A schematic diagram showing the flow direction of electrons and holes in a solar cell module.

[0025] Figure 7 for Figure 4 Current and voltage characteristics of solar cell modules.

[0026] Figure 8 This is a schematic diagram of a second structure of a solar cell module according to an embodiment of this application.

[0027] Figure 9 This is a schematic diagram of a third structure of a solar cell module according to an embodiment of this application.

[0028] Figure 10 This is a schematic diagram of the fourth structure of the solar cell module according to an embodiment of this application.

[0029] Figure 11 This is a schematic diagram of the fifth structure of a solar cell module according to an embodiment of this application.

[0030] Figure 12 This is a schematic diagram of the sixth structure of a solar cell module according to an embodiment of this application.

[0031] Figure 13 This is a flowchart illustrating the fabrication process of a bypass diode according to an embodiment of this application.

[0032] Figure 14 for Figure 13 A schematic diagram showing the connection between a thin-film diode module and a thin-film photovoltaic module.

[0033] Figure 15 This is a schematic diagram of a thin-film photovoltaic module in an embodiment of this application.

[0034] Figure 16 This is a first schematic diagram of a thin-film diode assembly in an embodiment of this application.

[0035] Figure 17 This is a second schematic diagram of a thin-film diode assembly in an embodiment of this application.

[0036] Figure 18 This is another fabrication flowchart of the bypass diode according to an embodiment of this application.

[0037] Figure 19 for Figure 18 A schematic diagram showing the connection between a thin-film diode module and a thin-film photovoltaic module.

[0038] Figure label:

[0039] 10-Power generation system; 20-Transparent substrate; 21-First electrode

[0040] 22-First charge transport layer; 23a-First light absorption layer; 23b-Second light absorption layer

[0041] 24-Second charge transport layer; 25-Second electrode; 26-Connection part

[0042] 27 - Bypass diode; 27a - First bypass diode; 27b - Second bypass diode

[0043] 27c - Third bypass diode; 28 - Sub-cell; 28a - First sub-cell

[0044] 28b - Second subcell; 28c - Third subcell; 29 - First substrate

[0045] 30 - Second substrate; 31 - Encapsulation layer; 32 - First conductive layer

[0046] 33-First semiconductor layer; 34-Second semiconductor layer; 35-Second conductive layer

[0047] 36-First conductive part; 37-Second conductive part; 38-Third conductive part

[0048] 39-Bottom cell membrane structure; 40-Composite layer; 41-Top cell membrane structure

[0049] 42-Third charge transport layer 43-Fourth charge transport layer Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0051] To facilitate understanding of the solar cell modules, photovoltaic strings, and power generation systems provided in the embodiments of this application, their application scenarios are described below. Solar energy, as a renewable and clean energy source, has led to extensive research into photovoltaic power generation technology, and the photovoltaic power generation industry has experienced rapid development in recent years. Figure 1 This is a schematic diagram of a power generation system provided in an embodiment of this application. Figure 1As shown, the power generation system 10 includes multiple components such as a photovoltaic string, a DC-DC converter, and an inverter. The photovoltaic string contains multiple solar cell modules (also called photovoltaic modules), which can be electrically connected in series, parallel, or a combination of series and parallel connections. Each solar cell module can perform photoelectric conversion, converting the energy of sunlight into direct current (DC) electricity. The DC-DC converter receives the DC power output from the photovoltaic string and outputs it after voltage conversion. The inverter receives the DC power output from the DC-DC converter and converts it into alternating current (AC). The AC power output from the inverter can be input to a load to supply power. Alternatively, the AC power output from the inverter can be connected to the power grid (e.g., an AC grid) via a grid-connected transformer, thus achieving grid connection of the power generation system 10.

[0052] As the core component of a photovoltaic power generation system 10, the operational stability of solar cell modules is a key factor affecting the power generation capacity of the system. In recent years, solar cell modules have received increasing attention due to their higher spectral utilization and higher conversion efficiency compared to single-cell solar cells. Based on this, solar cell modules can be used to form photovoltaic strings.

[0053] Figure 2 This is a schematic diagram of a conventional solar cell module. Figure 2 As shown, the cell structure of the solar cell module includes a transparent substrate 20 and multiple sub-cells disposed on one side of the transparent substrate 20. A sub-cell refers to an independent light-absorbing unit within the solar cell module. In practical applications, sub-cells are typically elongated and arranged along a first direction, with each sub-cell extending along a second direction. The first and second directions are perpendicular to each other, and both are perpendicular to the thickness direction D of the solar cell module. Of course, the sub-cells can also be configured in other shapes, which are not limited here.

[0054] To reduce energy loss, the solar cell module connects multiple sub-cells in series. Each sub-cell includes a first electrode 21, a first charge transport layer 22, a first light absorption layer 23a, a second charge transport layer 24, and a second electrode 25. Along the thickness direction D, the first electrode 21, first charge transport layer 22, first light absorption layer 23a, second charge transport layer 24, and second electrode 25 are sequentially disposed on one side of a transparent substrate 20, with the first electrode 21 located between the first charge transport layer 22 and the transparent substrate 20. The multiple sub-cells include first and second sub-cells connected in series. The first sub-cell has a connecting portion 26 that penetrates the cell structure, allowing the second electrode 25 in the first sub-cell to connect to the first electrode 21 in the second sub-cell, thus achieving series connection between the sub-cells. Alternatively, the connecting portion 26 and the second electrode 25 in the first sub-cell can be an integral structure, meaning the connecting portion 26 is formed when the second electrode 25 is formed.

[0055] Exemplarily, both the first electrode 21 and the second electrode 25 are made of transparent conductive materials, such as transparent conductive oxides (TCOs), like indium tin oxide (ITO), thereby forming the solar cell module in this embodiment as a bifacial solar cell module. Alternatively, the first electrode 21 is made of a transparent conductive material, such as TCO, and the second electrode 25 is made of a metallic material, such as Au, Ag, or Al, thereby forming the solar cell module in this embodiment as a unifacial solar cell module. The first electrode 21 and the second electrode 25 are used to collect charge carriers (holes or electrons) and conduct current, realizing the directional transport of photogenerated charge to the external circuit.

[0056] In some embodiments, the sub-cell can be a PIN junction-based cell. Specifically, the first electrode 21 can serve as the anode of the sub-cell, and the second electrode 25 can serve as the cathode. A first charge transport layer 22 is disposed adjacent to the first electrode 21. The first charge transport layer 22 can be a P-type hole transport layer (HTL). The first charge transport layer 22 is used to directionally transport holes generated by the first light absorption layer 23a to the first electrode 21, while intercepting electrons and protecting the first electrode 21. A second charge transport layer 24 is disposed adjacent to the second electrode 25. The second charge transport layer 24 can be an N-type electron transport layer (ETL). The second charge transport layer 24 is used to directionally transport electrons generated by the first light absorption layer 23a to the second electrode 25, while intercepting holes and protecting the second electrode 25.

[0057] In other embodiments, the sub-cell can be an NIP junction-based cell. Specifically, the first electrode 21 can serve as the cathode of the sub-cell, and the second electrode 25 can serve as the anode. A first charge transport layer 22 is disposed adjacent to the first electrode 21. The first charge transport layer 22 can be an ETL (Electronic Toll Collection Layer). The first charge transport layer 22 is used to directionally transport electrons generated by the first light absorption layer 23a to the first electrode 21, while simultaneously intercepting holes and protecting the first electrode 21. A second charge transport layer 24 is disposed adjacent to the second electrode 25. The second charge transport layer 24 can be an HTL (High-Temperature Toll Collection Layer). The second charge transport layer 24 is used to directionally transport holes generated by the first light absorption layer 23a to the second electrode 25, while simultaneously intercepting electrons and protecting the second electrode 25.

[0058] The first light-absorbing layer 23a, as the core component of the sub-cell, is used to capture photons and efficiently generate electron-hole pairs (also known as "excitons"). The first light-absorbing layer 23a can be made of perovskite. Perovskite solar cells have advantages such as high theoretical conversion efficiency, low manufacturing cost, and highly adjustable bandgap. The theoretical conversion efficiency limit of perovskite solar cells can reach 30%, and by stacking with crystalline silicon cells or perovskite cells with wide and narrow bandgap configurations, its theoretical conversion efficiency limit can even exceed 40%. The bandgap is the energy difference between the lowest point of the conduction band and the highest point of the valence band in a semiconductor material, measured in electron volts (eV). It is an important characteristic parameter of semiconductor materials and directly affects device performance.

[0059] Figure 3 This is a schematic diagram of a perovskite solar cell. Figure 3 As shown, the basic structure of a perovskite solar cell is a sandwich structure. Taking a PIN junction-based solar cell as an example, the perovskite solar cell includes a transparent substrate 20, ITO, HTL, a perovskite layer, ETL, and a metal electrode, wherein the perovskite layer is the first light-absorbing layer 23a of the sub-cell. The chemical formula of the perovskite layer is ABX3, where A... + Including CH3NH3 + (MA + ), NH2CH=NH2 + (FA + ), Cs + 、Rb + Wait, B 2+ Including Pb 2+ Sn 2+ Wait, X - Including Cl - ,Br - I -Perovskite materials contain halogen ions, with MAPbI3 being a classic example. Adjusting the composition of ABX3 allows for the control of the bandgap in perovskite solar cells from 1.2 eV to 2.5 eV, which is significant for solar cell design. Furthermore, perovskite materials consist of abundant elements found on Earth, resulting in lower material costs. When the perovskite layer absorbs light, it generates electron-hole pairs. These pairs move towards the ETL and HTL under the influence of a built-in electric field, ultimately reaching the electrodes and generating the photovoltaic effect. The highest conversion efficiencies currently achieved for small-area perovskite solar cells, perovskite / crystalline silicon tandem cells, and all-perovskite tandem cells have reached 27%, 34.7%, and 31%, respectively, while the highest conversion efficiency for large-area perovskite solar cells has exceeded 20%.

[0060] In practical applications, photovoltaic strings are installed outdoors. Due to the unpredictable nature of the external environment, shadows (such as tree shade, building shadows, litter, or dust) may occur, obstructing the solar cell modules. The shaded cells, due to insufficient sunlight, experience a sharp drop in output current, or even fail to output current at all. Because the series circuit requires consistent current, the current generated by the cell connected in series with the shaded cell becomes excessive. This excess current is forcibly injected into the shaded cell, causing it to be reverse-biased, i.e., subjected to a high reverse bias voltage. This can lead to a surge in cell temperature, even breakdown, potentially resulting in localized melting or fire, and causing safety accidents.

[0061] In view of this, this application provides a solar cell module, photovoltaic string, and power generation system that, when a sub-cell is shaded, bypasses the shaded sub-cell by using a bypass diode, thereby avoiding the temperature spike and breakdown caused by reverse bias of the sub-cell, and thus improving the safety and stability of the solar cell module.

[0062] It should be noted that the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to be a limitation of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise.

[0063] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0064] The photovoltaic string of this application uses a solar cell module equipped with a bypass diode. When a sub-cell of the solar cell module is shaded, the bypass diode can bypass the shaded sub-cell, thereby preventing the shaded sub-cell from being reverse biased, which would cause a temperature spike and breakdown, and thus improve the safety and stability of the photovoltaic module.

[0065] Figure 4 This is a schematic diagram of a first structural embodiment of a solar cell module according to this application. Figure 4 As shown, the solar cell module includes multiple battery modules. Each battery module includes a bypass diode 27 and a battery. In the solar cell module, the batteries of the aforementioned multiple battery modules are connected in series, and the bypass diodes 27 of the aforementioned multiple battery modules are also connected in series. A battery may include one or more sub-cells 28, and when a battery includes multiple sub-cells 28, these sub-cells 28 are connected in series. Therefore, all the sub-cells 28 of the solar cell module are connected in series, and all the bypass diodes 27 are connected in series. In the battery module, the anode of the bypass diode 27 is electrically connected to the cathode of the battery, and the cathode of the bypass diode 27 is electrically connected to the cathode of the battery, i.e., the bypass diode 27 is connected in reverse parallel with the battery. The bypass diode 27 is used to bypass the battery when the output current of any sub-cell 28 is less than a set current, which can be less than or equal to the output current of the sub-cell 28 under normal operating conditions. The forward voltage of the bypass diode 27 can be less than or equal to 2V.

[0066] In embodiments of this application, the solar cell module includes a first substrate 29 and a second substrate 30, which are disposed opposite to each other along the thickness direction D. The cell is disposed on the surface of the first substrate 29 facing the second substrate 30, and a bypass diode 27 is disposed on the surface of the second substrate 30 facing the first substrate 29. The bypass diode 27 is fixedly connected to the cell through an encapsulation layer 31 formed by encapsulating adhesive.

[0067] In the aforementioned solar cell module, the bypass diode 27 features a low turn-on voltage. When the sub-cell 28 is shaded and reverse-biased, the bypass diode 27, which is connected in parallel with the cell containing the sub-cell 28, conducts, thereby bypassing the cell. In other words, the two cells connected in series with the sub-cell are directly connected by the bypass diode 27, preventing the cell from entering the high-voltage reverse-biased region, thus improving the safety of the solar cell module.

[0068] Figure 5 for Figure 2 The current-voltage characteristics of solar cell modules. For example... Figure 2 and Figure 5 As shown, the unshaded sub-cell 28 can function normally under normal illumination and generate photovoltage and photocurrent. The shaded sub-cell 28, unable to generate photovoltage and photocurrent, enters the reverse-biased region. The flow direction of electrons and holes in the battery assembly containing this sub-cell 28 is as follows... Figure 2 As shown. To ensure maximum power output, the unshaded sub-cell 28 operates near its optimal power. To achieve current matching, the shaded sub-cell 28 needs to be placed in the reverse bias region and subjected to a high reverse bias voltage.

[0069] Figure 6 for Figure 4 A schematic diagram showing the direction of current flow in a solar cell module. Figure 7 for Figure 4 The current-voltage characteristics of solar cell modules. For example... Figure 6 and Figure 7 As shown in the embodiments of this application, the solar cell module includes cells connected in reverse parallel and a bypass diode 27, which has a low turn-on voltage characteristic. When the sub-cell 28 is shaded, due to the low turn-on voltage characteristic of the bypass diode 27, the PN junction of the bypass diode 27 enters forward bias, and most of the current is bypassed through the PN junction. At the same time, the reverse bias voltage applied to the shaded sub-cell 28 is only slightly higher than the PN turn-on voltage, thereby preventing the shaded sub-cell 28 from entering the high bias region or the breakdown region, effectively protecting the shaded sub-cell 28.

[0070] In addition, since the battery as a whole is connected in reverse parallel with the bypass diode 27, regardless of whether the battery includes one or more sub-cells 28, once any one or more sub-cells 28 of the battery are blocked, the bypass diode 27 connected in reverse parallel with the battery can bypass the entire battery. In this way, the number of bypass diodes 27 can be set according to actual needs.

[0071] like Figure 4 As shown, in some embodiments, the battery may include a sub-battery 28 connected in reverse parallel with a bypass diode 27. Figure 8This is a schematic diagram of a second structure of a solar cell module according to an embodiment of this application. Figure 9 This is a schematic diagram of a third structure of a solar cell module according to an embodiment of this application. Figure 10 This is a schematic diagram of the fourth structure of a solar cell module according to an embodiment of this application. Figures 8-10 As shown, in some other embodiments, the battery may include a plurality of sub-cells 28 connected in series and in reverse parallel with a bypass diode 27.

[0072] Along the thickness direction D, the bypass diode 27 includes a first conductive layer 32, a first semiconductor layer 33, a second semiconductor layer 34, and a second conductive layer 35. The first conductive layer 32 is located between the second electrode 25 and the first semiconductor layer 33, and the first semiconductor layer is electrically connected to the first conductive layer 32. The second semiconductor layer 34 is electrically connected to the second conductive layer 35. When the sub-cell 28 is a PIN junction-based cell, the first electrode 21 is the positive electrode of the sub-cell 28, the first charge transport layer 22 is a hole transport layer, the second charge transport layer 24 is an electron transport layer, and the second electrode 25 is the negative electrode of the sub-cell 28. The bypass diode 27 can be a PN type diode. Specifically, the first semiconductor layer 33 is a P-type semiconductor layer, and the second semiconductor layer 34 is an N-type semiconductor layer. When the sub-cell can be an NIP junction-based cell, the first electrode 21 is the negative electrode of the sub-cell 28, the first charge transport layer 22 is an electron transport layer, the second charge transport layer 24 is a hole transport layer, and the second electrode 25 is the positive electrode of the sub-cell 28. The bypass diode 27 can be an NP-type diode. Specifically, the first semiconductor layer 33 is an N-type semiconductor layer, and the second semiconductor layer 34 is a P-type semiconductor layer.

[0073] In some embodiments, the electrical connection between the same sub-cell 28 and the two bypass diodes 27 connected in series can be achieved through the same conductive part. For example... Figure 4As shown, the bypass diode 27 further includes a first conductive portion 36, which is connected to the second conductive layer 35. The aforementioned multiple battery assemblies include a first battery assembly, a second battery assembly, and a third battery assembly. For ease of explanation, an example is given where the battery includes a sub-battery 28. Specifically, the first battery assembly includes a first sub-battery 28a and a first bypass diode 27a; the second battery assembly includes a second sub-battery 28b and a second bypass diode 27b; and the third battery assembly includes a third sub-battery 28c and a third bypass diode 27c. The second electrode 25 of the first sub-battery 28a is connected to the first electrode 21 of the second sub-battery 28b via a connecting portion 26, and the second electrode 25 of the second sub-battery 28b is connected to the first electrode 21 of the third sub-battery 28c via the connecting portion 26. The first conductive layer 32 of the first bypass diode 27a is connected to the second electrode 25 of the first sub-battery 28a through the first conductive portion 36 of the second bypass diode 27b. The second conductive layer 35 of the second bypass diode 27b is connected to the second electrode 25 of the first sub-cell 28a through the first conductive portion 36 of the second bypass diode 27b. The first conductive layer 32 of the second bypass diode 27b is connected to the second electrode 25 of the second sub-cell 28b through the first conductive portion 36 of the third bypass diode 27c. The second conductive layer 35 of the third bypass diode 27c is connected to the second electrode 25 of the second sub-cell 28b through the first conductive portion 36 of the third bypass diode 27c. The first conductive portion 36 can realize reverse parallel connection and series connection between bypass diodes 27, thereby simplifying the structure of the solar cell module and reducing manufacturing costs.

[0074] In the above embodiments, along the thickness direction D, the projection of the first conductive layer 32 of the first bypass diode 27a overlaps with the projection of the second electrode 25 of the first sub-cell 28a; the projection of the second conductive layer 35 of the second bypass diode 27b overlaps with the projection of the second electrode 25 of the first sub-cell 28a; and the projection of the second conductive layer 35 of the second bypass diode 27b overlaps with the projection of the second electrode 25 of the second sub-cell 28b. The projection of the second conductive layer 35 of the third bypass diode 27c overlaps with the projection of the second electrode 25 of the second sub-cell 28c. The extension direction of the first conductive portion 36 is parallel to the thickness direction D, thereby reducing the size of the first conductive portion 36 for ease of manufacturing and cost savings.

[0075] like Figure 8As shown, in one embodiment, the multiple battery components include a first battery component, a second battery component, and a third battery component. The first battery component includes four sub-cells 28 and a first bypass diode 27a, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the first bypass diode 27a, and the four sub-cells 28 include the first sub-cell 28a. The second battery component includes four sub-cells 28 and a second bypass diode 27b, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the second bypass diode 27b, and the four sub-cells 28 include the second sub-cell 28b and a third sub-cell 28c. The third battery component includes four sub-cells 28 and a third bypass diode 27c, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the third bypass diode 27c, and the four sub-cells 28 include a fourth sub-cell 28d. The first sub-cell 28 and the second sub-cell 28b are connected in series, and the third sub-cell 28c and the fourth sub-cell 28d are connected in series. The first conductive layer 32 of the first bypass diode 27a and the second conductive layer 35 of the second bypass diode 27b are both connected to the second electrode 25 of the first sub-cell 28a through the first conductive portion 36 of the second bypass diode 27b. The first conductive layer 32 of the second bypass diode 27b and the second conductive layer 35 of the third bypass diode 27c are both connected to the second electrode 25 of the second sub-cell 28b through the first conductive portion 36 of the third bypass diode 27c.

[0076] like Figure 9 and Figure 10As shown, in another embodiment, the multiple battery components include a first battery component, a second battery component, and a third battery component. The first battery component includes four sub-cells 28 and a first bypass diode 27a, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the first bypass diode 27a, and the four sub-cells 28 include the first sub-cell 28a. The second battery component includes four sub-cells 28 and a second bypass diode 27b, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the second bypass diode 27b, and the four sub-cells 28 include the second sub-cell 28b and a third sub-cell 28c. The third battery component includes four sub-cells 28 and a third bypass diode 27c, wherein the four sub-cells 28 are connected in series and then in reverse parallel with the third bypass diode 27c, and the four sub-cells 28 include a fourth sub-cell 28d. The first sub-cell 28 and the second sub-cell 28b are connected in series, and the third sub-cell 28c and the fourth sub-cell 28d are connected in series. The first conductive layer 32 of the first bypass diode 27a is directly connected to the second electrode 25 of the first sub-cell 28a, and the first conductive layer 32 of the first bypass diode 27a is directly connected to the second conductive layer 35 of the second bypass diode 27b. The first conductive layer 32 of the second bypass diode 27b is directly connected to the second electrode 25 of the second sub-cell 28b, and the first conductive layer 32 of the second bypass diode 27b is directly connected to the second conductive layer 35 of the third bypass diode 27c.

[0077] In other embodiments, the electrical connection between the positive terminal of the bypass diode 27 and the negative terminal of the battery in the same battery, and the electrical connection between the negative terminal of the bypass diode 27 and the negative terminal of the adjacent battery, can be achieved by different conductive parts. Figure 11 This is a schematic diagram of a fifth structure of a solar cell module according to an embodiment of this application. (As shown...) Figure 11As shown, the bypass diode 27 further includes a second conductive portion 37 and a third conductive portion 38. The second conductive portion 37 is connected to the first conductive layer 32, and the third conductive portion 38 is connected to the second conductive layer 35. Specifically, the connections between the first battery assembly, the second battery assembly, and the third battery assembly are as follows: the second electrode 25 of the first sub-battery 28a is connected to the first electrode 21 of the second sub-battery 28b via a connecting portion 26, and the second electrode 25 of the second sub-battery 28b is connected to the first electrode 21 of the third sub-battery 28c via a connecting portion 26. The first conductive layer 32 of the first bypass diode 27a is connected to the second electrode 25 of the first sub-battery 28a via the second conductive portion 37 of the first bypass diode 27a. The first conductive layer 32 of the second bypass diode 27b is connected to the second electrode 25 of the second sub-battery via the second conductive portion 37 of the second bypass diode 27b, and the second conductive layer 35 of the second bypass diode 27b is connected to the second electrode 25 of the first sub-battery 28a via the third conductive portion 38 of the second bypass diode 27b. The second conductive layer 35 of the third bypass diode 27c is connected to the second electrode 25 of the second sub-cell 28b through the third conductive part 38 of the third bypass diode 27c.

[0078] like Figure 4 As shown, along the thickness direction D, the projection of the first conductive layer 32 of the first bypass diode 27a overlaps with the projection of the second electrode 25 of the first sub-cell 28a; the projection of the first conductive layer 32 of the second bypass diode 27b overlaps with the projection of the second electrode 25 of the second sub-cell 28b; and the projection of the first conductive layer 32 of the third bypass diode 27c overlaps with the projection of the second electrode 25 of the third sub-cell 28c. The extension direction of the second conductive portion 37 is parallel to the thickness direction D, which allows the second conductive portion 37 to be fabricated vertically during manufacturing, facilitating processing.

[0079] Along the thickness direction D, the projection of the second conductive layer 35 of the second bypass diode 27b overlaps with the projection of the first conductive layer 32 of the first bypass diode 27a, and the projection of the second conductive layer 35 of the third bypass diode 27c overlaps with the projection of the first conductive layer 32 of the second bypass diode 27b. The extension direction of the third conductive portion 38 is parallel to the thickness direction D, so that the third conductive portion 38 can be fabricated vertically during manufacturing, which is convenient for processing.

[0080] In addition, along the thickness direction D, the projections of the first conductive layer 32, the first semiconductor layer 33, the second semiconductor layer 34, and the second conductive layer 35 overlap. Therefore, the first conductive layer 32 and the first semiconductor layer 33, the first semiconductor layer 33 and the second semiconductor layer 34, and the second semiconductor layer 34 and the second conductive layer 35 are all electrically connected through direct contact, without the need for other electrical connection structures, thereby simplifying the structure of the solar cell module.

[0081] It is understandable that the bypass diode 27 is connected to the sub-cell 28 via the encapsulation layer 31. The encapsulation layer 31 is typically made of encapsulating adhesive. Therefore, during the fabrication of the solar cell module, the sub-cells 28 and bypass diodes 27 can be fabricated separately, and after fabrication, multiple sub-cells 28 and multiple bypass diodes 27 can be connected together using encapsulating adhesive. In this way, the fabrication of the bypass diode 27 will not affect the fabrication of the sub-cells 28, and when the solar cell module is operating normally, the bypass diode 27 will not affect the normal operation of the sub-cells 28.

[0082] To realize a tandem solar cell module, sub-cell 28 may include multiple photoelectric conversion structures stacked together. Furthermore, to enable electrical connection between adjacent photoelectric conversion structures, sub-cell 28 also includes a composite layer disposed between two adjacent photoelectric conversion structures. The material of the composite layer needs to be compatible with both transparency and conductivity; a transparent conductive material, such as TCO, can be selected.

[0083] Figure 12 This is a schematic diagram of the sixth structure of a solar cell module according to an embodiment of this application. Figure 12 As shown, in a specific embodiment, the sub-cell 28 can be a double-junction cell structure. Specifically, the sub-cell 28 includes a bottom cell film structure 39, a composite layer 40, and a top cell film structure 41 stacked together. The bottom cell film structure 39 is located on the first electrode 21, the top cell film structure 41 is located on top of the bottom cell film structure 39 along the thickness direction D, the composite layer 40 is located between the bottom cell film structure 39 and the top cell film structure 41, and the second electrode 25 is located on top of the top cell film structure 41. The composite layer 40 is used to connect the bottom cell film structure 39 and the top cell film structure 41 in series, and allows light not absorbed by the top cell film structure 41 to penetrate to the bottom cell film structure 39. The bottom cell film structure 39 includes a first charge transport layer 22, a first light absorption layer 23a, and a second charge transport layer 24, and the top cell film structure 41 includes a third charge transport layer 42, a second light absorption layer 23b, and a fourth charge transport layer 43. The bottom cell film structure 39 and the top cell film structure 41 are independent of each other. In practical applications, the bottom cell film structure 39 and the top cell film structure 41 can absorb light of different wavelengths, thereby maximizing the utilization of photons and improving the photoelectric conversion efficiency of the solar cell module.

[0084] In another specific embodiment, the sub-cell 28 can also be a triple-junction cell structure. Specifically, the sub-cell 28 includes a top cell film structure, a middle cell film structure, and a bottom cell film structure stacked together. The top cell structure and the middle cell film structure, as well as the middle cell film structure and the bottom cell film structure, are connected by a composite layer 40. Exemplarily, the light-absorbing layer of the top cell film structure can be made of perovskite and GaInP, and the band gap range of the top cell film structure can be 1.6-1.8 eV, capable of absorbing short-wavelength light such as blue-green light. The light-absorbing layer of the middle cell film structure can be made of gallium arsenide (GaAs) and organic semiconductors, and the band gap range of the middle cell film structure can be 1.3-1.4 eV, capable of absorbing mid-wavelength light such as yellow-orange light. The light-absorbing layer of the bottom cell film structure can be made of crystalline silicon and CIGS, and the band gap range of the bottom cell film structure can be 1.0-1.2 eV, capable of absorbing long-wavelength light such as red / infrared light.

[0085] Figure 13 This is a flowchart illustrating the fabrication process of a bypass diode according to an embodiment of this application. Figure 13 As shown, in step 1, laser scribing is performed on the backplane glass with the conductive layer to form multiple conductive strips (i.e., the second conductive layer 35). In step 2, a PN junction thin film is deposited on the second conductive layer 35. In step 3, multiple PN junction strips are formed on the PN junction thin film using laser scribing. The grooves in the laser scribing and the grooves between adjacent second conductive layers 35 have a certain misalignment distance in the thickness direction D, so that the first conductive part 36 can be connected to the first conductive layer 32 when the first conductive layer 32 is subsequently prepared. In step 4, the conductive layer is deposited, and a third laser scribing is performed to form the first conductive layer 32 and form a thin-film diode assembly. In step 5, metal contact points with a certain height are prepared on the thin-film diode assembly using methods such as screen printing. These metal contact points serve as the connectors to the first light-absorbing layer 23a of the sub-cell 28. Figure 14 for Figure 13 A schematic diagram showing the connection between a thin-film diode module and a thin-film photovoltaic module. (See diagram below.) Figure 14 As shown, Figure 13 The thin-film diode module and the thin-film photovoltaic module are laminated back to back using encapsulating adhesive to form a solar cell module.

[0086] In step 1, such as Figure 4 and Figure 9 As shown, the number of the second conductive layer 35 can be equal to the number of bypass diodes 27; or, as... Figure 10 As shown, the number of second conductive layers 35 can also be greater than the number of bypass diodes 27, and the second conductive layers 35 that are not connected to the PN junction do not participate in the operation of the bypass diodes 27.

[0087] In the above-mentioned thin-film diode assembly, the bypass diode 27 can have various shapes along the direction of the battery strip. Figure 15 This is a schematic diagram of a thin-film photovoltaic module in an embodiment of this application. Figure 16 This is a first schematic diagram of a thin-film diode assembly in an embodiment of this application. For example... Figure 16 As shown, in some embodiments, the cells of the thin-film photovoltaic module are in the form of cell strips. A single bypass diode 27 can be elongated along the extension direction of the cell strip, and the length of the single bypass diode 27 is close to the length of the cell strip. Figure 17 This is a second schematic diagram of a thin-film diode assembly in an embodiment of this application. For example... Figure 17 As shown, a single bypass diode 27 can also be a short segment along the extension direction of the battery strip, that is, multiple bypass diodes 27 are present along the length of a battery strip.

[0088] Figure 18 This is another fabrication flowchart of the bypass diode according to an embodiment of this application. Figure 19 for Figure 18 A schematic diagram showing the connection between a thin-film diode module and a thin-film photovoltaic module. (See diagram below.) Figure 18 and Figure 19 As shown, in some other embodiments, metal contacts may not be fabricated when manufacturing the thin-film diode assembly. Metal contacts can be directly fabricated on the surface of the thin-film photovoltaic module, and then the thin-film diode assembly is connected to the thin-film photovoltaic module by lamination to achieve electrical contact between the anti-parallel bypass diode 27 and the sub-cell 28.

[0089] In actual fabrication, the production line can fabricate thin-film diode modules and thin-film photovoltaic modules in parallel, and then achieve coupling between the thin-film diode modules and thin-film photovoltaic modules through lamination. In this way, when fabricating the bypass diode 27, there is no need to consider the high-temperature intolerance of the first light-absorbing layer 23a or other materials, and high-temperature deposited semiconductor thin-film materials can be selected, making the material selection for the bypass diode 27 more extensive.

[0090] In addition to fabricating perovskite solar cell modules, the above-mentioned fabrication process can also be used to fabricate indium gallium selenide / perovskite tandem solar cell modules, as well as perovskite / organic tandem solar cell modules, etc., which will not be listed here.

[0091] Furthermore, the thin-film diode module and the thin-film photovoltaic module are fabricated independently, which can effectively improve the yield of the modules. After the thin-film photovoltaic module is fabricated, there is no need to consider the failure of the entire solar cell module caused by the deposition failure of the thin-film diode module, or the failure of the solar cell module caused by damage to the first light-absorbing layer 23a in the manufacturing process, which can reduce the fabrication difficulty.

[0092] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A solar cell module, characterized in that, The solar cell module includes a first substrate and a second substrate disposed opposite to each other along the thickness direction. A plurality of battery modules are disposed between the first substrate and the second substrate. Each battery module includes a battery and a bypass diode. The batteries of the plurality of battery modules are connected in series, and the bypass diodes of the plurality of battery modules are connected in series. The battery is located on the surface of the first substrate facing the second substrate, and the bypass diode is located on the surface of the second substrate facing the first substrate; the positive terminal of the bypass diode is electrically connected to the negative terminal of the battery, and the negative terminal of the bypass diode is electrically connected to the positive terminal of the battery; the battery includes at least one sub-battery connected in series, and the bypass diode is used to bypass the battery when the output current of any sub-battery is less than a set current.

2. The solar cell module as described in claim 1, characterized in that, The sub-cell includes a first electrode, a first charge transport layer, a first light absorption layer, a second charge transport layer, and a second electrode, which are sequentially stacked along the thickness direction. The first electrode is located between the first substrate and the first charge transport layer. The bypass diode includes a first conductive layer, a first semiconductor layer, a second semiconductor layer, and a second conductive layer stacked sequentially along the thickness direction. The first conductive layer is located between the first semiconductor layer and the second electrode. The first semiconductor layer is electrically connected to the first conductive layer, and the second semiconductor layer is electrically connected to the second conductive layer. The first conductive layer is electrically connected to the second electrode of the battery, and the second conductive layer is electrically connected to the second electrode of an adjacent battery. An encapsulation layer is provided between the second electrode and the first conductive layer.

3. The solar cell module as described in claim 2, characterized in that, The first electrode is a transparent electrode; the first charge transport layer is a hole transport layer; the second charge transport layer is an electron transport layer; and the second electrode is a metal electrode or a transparent electrode. The first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer; or... The first electrode is a transparent electrode, the first charge transport layer is an electron transport layer, the second charge transport layer is a hole transport layer, and the second electrode is a transparent electrode; the first semiconductor layer is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer.

4. The solar cell module as described in claim 2 or 3, characterized in that, The bypass diode further includes a first conductive portion, which is connected to the second conductive layer; The plurality of battery components include a first battery component, a second battery component, and a third battery component. The first battery component includes a first sub-cell and a first bypass diode. The second battery component includes a second sub-cell and a second bypass diode. The third battery component includes a third sub-cell and a third bypass diode. The second electrode of the first sub-cell is connected to the first electrode of the second sub-cell, and the second electrode of the second sub-cell is connected to the first electrode of the third sub-cell. The first conductive layer of the first bypass diode is connected to the second electrode of the first sub-cell through the first conductive portion of the second bypass diode; the second conductive layer of the second bypass diode is connected to the second electrode of the first sub-cell through the first conductive portion of the second bypass diode; the first conductive layer of the second bypass diode is connected to the second electrode of the second sub-cell through the first conductive portion of the third bypass diode; the second conductive layer of the third bypass diode is connected to the second electrode of the second sub-cell through the first conductive portion of the third bypass diode.

5. The solar cell module as described in claim 2 or 3, characterized in that, The bypass diode further includes a second conductive portion and a third conductive portion; the second conductive portion is connected to the first conductive layer, and the third conductive portion is connected to the second conductive layer. The plurality of battery components include a first battery component, a second battery component, and a third battery component. The first battery component includes a first sub-cell and a first bypass diode. The second battery component includes a second sub-cell and a second bypass diode. The third battery component includes a third sub-cell and a third bypass diode. The second electrode of the first sub-cell is connected to the first electrode of the second sub-cell, and the second electrode of the second sub-cell is connected to the first electrode of the third sub-cell. The first conductive layer of the first bypass diode is connected to the second electrode of the first sub-cell through the second conductive portion of the first bypass diode; the first conductive layer of the second bypass diode is connected to the second electrode of the second sub-cell through the second conductive portion of the second bypass diode; the second conductive layer of the second bypass diode is connected to the second electrode of the first sub-cell through the third conductive portion of the second bypass diode; the second conductive layer of the third bypass diode is connected to the second electrode of the second sub-cell through the third conductive portion of the third bypass diode.

6. The solar cell module as described in claim 4 or 5, characterized in that, Along the thickness direction, the projection of the first conductive layer of the first bypass diode overlaps with the projection of the second electrode of the first sub-cell; the projection of the second conductive layer of the second bypass diode overlaps with the projection of the second electrode of the first sub-cell; the projection of the first conductive layer of the second bypass diode overlaps with the projection of the second electrode of the second sub-cell; the projection of the second conductive layer of the third bypass diode overlaps with the projection of the second electrode of the second sub-cell; the extending direction of the first conductive portion or the second conductive portion is parallel to the thickness direction.

7. The solar cell module as described in claim 6, characterized in that, Along the thickness direction, the projections of the first conductive layer, the first semiconductor layer, the second semiconductor layer, and the second conductive layer overlap.

8. The solar cell module as described in any one of claims 2-7, characterized in that, The sub-battery further includes a composite layer, a third charge transport layer, a second light absorption layer, and a fourth charge transport layer stacked sequentially between the second charge transport layer and the second electrode, with the composite layer located between the second charge transport layer and the third charge transport layer.

9. The solar cell module as described in any one of claims 1-8, characterized in that, The forward conduction voltage of the bypass diode is less than or equal to 2V.

10. A photovoltaic string, characterized in that, It includes multiple solar cell modules as described in any one of claims 1-9.

11. A power generation system, characterized in that, It includes the photovoltaic string, DC-DC converter, and inverter as described in claim 10; the photovoltaic string is connected to the inverter through the DC-DC converter, the DC-DC converter is used to convert the DC power output from the photovoltaic string into voltage and output it to the inverter; the inverter is used to convert the DC power output from the DC-DC converter into AC power and output it.

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