Photovoltaic module configured with multiple bypass diodes

Abstract

The utility model discloses a photovoltaic module configured with a plurality of bypass diodes, comprising a front plate and a back plate, m battery strings and p diode strings are packaged between the front plate and the back plate through an adhesive layer, each battery string comprises n battery pieces connected in series, each diode string comprises q bypass diodes connected in series, the n battery pieces are arranged in a straight line in consistent orientation, the q bypass diodes are arranged in a straight line in consistent orientation, the diode strings are parallel to or overlapped with the battery strings, the diode strings are reversely connected with one or more corresponding battery strings in parallel, the diodes are reversely connected with one or more corresponding battery pieces in parallel, m, n, p and q are positive integers, m is larger than or equal to 1, n is larger than or equal to 2, p is smaller than or equal to m, and q is smaller than or equal to n. According to the utility model, the bypass diodes are connected in parallel with all the battery pieces or a specified part of the battery pieces in the photovoltaic module, and the reliability of the photovoltaic module is obviously improved.

Description

Technical Field

[0001] The utility model specifically relates to a photovoltaic module configured with a plurality of bypass diodes, belonging to the technical field of photovoltaic module manufacturing. Background Art

[0002] A photovoltaic module is formed by connecting a certain number of photovoltaic cells in series and parallel according to a set order to form a photovoltaic power generation panel with a certain voltage and current. Conventional photovoltaic modules such as 60-cell type and 72-cell type respectively divide 60 cells and 72 cells into 6 series of cell strings, with 10 cells and 12 cells in each string. On the one hand, these 6 series of cell strings are all connected in series. On the other hand, a reverse-parallel diode is connected between every two adjacent series of cell strings on the side close to the lead-out wire, with a total of three diodes. These three diodes and two lead-out wires are integrated inside the junction box of a photovoltaic module. This diode is called a bypass diode in the industry according to its functional attributes. Because when any one or more cells in the two series of cell strings corresponding to it are damaged or shaded, resulting in no power generation or a significant reduction in current, this diode conducts, and the current generated by other normally generating cell strings will partially or completely pass through this diode. This diode plays a bypass role, which can prevent the damaged or shaded cells from heating up and being damaged due to becoming a load, and can reduce the loss of power generation of the photovoltaic module. This conventional photovoltaic module configured with three bypass diodes can be used in large-scale photovoltaic power stations, because the non-generation of one or more series of cell strings in a photovoltaic module has a very small impact on the entire photovoltaic power station, which can be said to be negligible. However, for portable mobile photovoltaic modules used outdoors alone or in small numbers of series-parallel combinations, even if one cell is damaged, it will affect the power generation output of its entire system. Therefore, it is necessary to connect bypass diodes in parallel to all cells or specified parts of cells in the photovoltaic module to improve its reliability, but the existing photovoltaic module design cannot meet this requirement and cannot integrate all bypass diodes into the photovoltaic module. Summary of the Invention

[0003] Aiming at the problems existing in the prior art, the utility model provides a photovoltaic module configured with a plurality of bypass diodes.

[0004] The technical solution adopted by the utility model is as follows:

[0005] A photovoltaic module configured with multiple bypass diodes, comprising a front plate and a back plate. Between the front plate and the back plate, m battery strings and p diode strings are encapsulated through a lamination layer. Each battery string includes n serially connected solar cells, and each diode string includes q serially connected bypass diodes. The n solar cells are aligned in the same orientation in a straight line, and the q bypass diodes are aligned in the same orientation in a straight line. The diode string is parallel or overlapped with the battery string, and the diode string is reversely connected in parallel with one or more corresponding battery strings, and the diode is reversely connected in parallel with one or more corresponding solar cells, where m, n, p, and q are all positive integers, m≥1, n≥2, p≤m, and q≤n.

[0006] Further, the diode string includes a substrate layer, and a plurality of the diodes are disposed on the substrate layer. The positive and negative electrodes between adjacent diodes are electrically connected through a conductive layer, and the positive and negative electrodes of the two diodes at both ends are also led out through the conductive layer.

[0007] Further, the photovoltaic module further includes a plurality of conductive tapes, and the conductive tapes lead out the positive and / or negative electrodes of the corresponding solar cells and are respectively electrically connected to the negative and / or positive electrodes of the corresponding diodes.

[0008] Further, the substrate layer is an insulating substrate layer, and a plurality of windows are provided on the insulating substrate layer, and the windows can conduct the conductive layer on the insulating substrate layer downward.

[0009] Beneficial effects: In the present utility model, m battery strings and p diode strings are encapsulated through a lamination layer between the front plate and the back plate of the photovoltaic module. The diode string is parallel or overlapped with the battery string, the diode string is reversely connected in parallel with one or more corresponding battery strings, and the diode is reversely connected in parallel with one or more corresponding solar cells, and the diodes and the solar cells are synchronously encapsulated in the lamination layer of the photovoltaic module, thereby improving the reliability of the entire photovoltaic module and facilitating production and manufacturing; when any one or more solar cells in the photovoltaic module are blocked or damaged, there are corresponding bypass diodes for bypass protection, minimizing the impact on the power generation output of the photovoltaic module. Description of the Drawings

[0010] Figure 1 is a schematic layout diagram of the photovoltaic module in Embodiment 1.

[0011] Figure 2 is Figure 1 the circuit diagram of

[0012] Figure 3 is a schematic layout diagram of the photovoltaic module in Embodiment 2.

[0013] Figure 4 is Figure 3 the circuit diagram of

[0014] Figure 5It is a schematic layout diagram of a photovoltaic module in Embodiment 3.

[0015] Figure 6 It is Figure 5 the circuit diagram of.

[0016] Figure 7 It is a schematic layout diagram of a photovoltaic module in Embodiment 4.

[0017] Figure 8 It is Figure 7 the circuit diagram of.

[0018] Figure 9 It is a schematic layout diagram of a photovoltaic module in Embodiment 5.

[0019] Figure 10 ]>It is Figure 9 the circuit diagram of.

[0020] Figure 11 It is a schematic diagram of a diode string structure.

[0021] Figure 12 It is a schematic diagram of a conventional cell structure.

[0022] Figure 13 It is a schematic layout diagram of a photovoltaic module in Embodiment 6.

[0023] Figure 14 It is a schematic diagram of the positive and negative grid line structures on the back of a back-contact cell.

[0024] Figure 15 It is a schematic diagram of the intermediate circuit layer structure in Embodiment 7.

[0025] Figure 16 It is a schematic diagram after connecting cells and diodes on the intermediate circuit layer in Embodiment 7.

[0026] Markings in the figure: 1 battery string, 2 diode string, 3 conductive tape, 4 bus bar, 10 interconnection strip, 11 cell, 12 positive lead-out wire, 13 negative lead-out wire, 21 substrate layer, 22 diode, 23 conductive layer, 111 positive grid line, 112 negative grid line, 211 substrate blade, 212 window, 213 lead-out wire group, 2131 positive lead-out wire, 2132 negative lead-out wire, 214 interconnection wire, 215 bus wire, 216 drainage wire, 217 diode connection terminal, 218 positioning mark, 219 component positive and negative connection terminal. Detailed implementation manners

[0027] To better understand the technical solution of this application, the following provides a clear, complete and detailed description of this application with reference to the accompanying drawings. It should be clear that the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0028] The structure of a conventional photovoltaic module generally includes a front plate and a back plate. Photovoltaic cells are encapsulated between the front plate and the back plate through an encapsulant layer. The front plate usually uses a transparent material such as glass or other organic transparent materials, and the back plate usually uses an organic polymer material such as TPT or other organic materials or inorganic materials. The encapsulant layer usually uses two layers of EVA materials. After multiple cells are interconnected and located between the two layers of EVA materials, they are temporarily bonded and fixed with positioning tape to prevent the cell string from shifting. After high-temperature vacuum lamination, the EVA materials undergo a cross-linking reaction and merge into one body to wrap the cells and bond the front plate and the back plate into a whole. Finally, after installing the junction box and the frame, the finished photovoltaic module is obtained.

[0029] This patent makes improvements on the basis of the existing photovoltaic modules. This patent provides a photovoltaic module configured with multiple bypass diodes. Between the front plate and the back plate, m cell strings and p diode strings are encapsulated through an encapsulant layer. Each cell string includes n serially connected cells, and each diode string includes q serially connected bypass diodes; the cells are divided into conventional crystalline silicon cells or back-contact cells. The structure of the conventional cells is as Figure 12 shown. The conventional cell 11 includes two sides, corresponding to the positive / negative electrode (or negative / positive electrode) of the cell. Grid lines are provided on both sides and welded to lead out multiple positive and negative lead interconnection bars. The positive lead 12 is led out from the back side (reverse side) of the cell shown in the figure, and the negative lead 13 is led out from the front side of the cell; the distinction of the positive and negative polarities on both sides of the cell is related to the manufacturing process of the cell. The size of the cell can be a conventional complete square size such as 125*125mm, 156*156mm, 182*182mm, 210*210mm, etc., or 1 / 2 slice, 1 / 3 slice, 1 / 4 slice, etc. of the complete size; n cells are arranged in the same orientation in a straight line, and the positive and negative electrodes of adjacent cells are connected. q bypass diodes are arranged in the same orientation in a straight line, and the positive and negative electrodes of adjacent diodes are connected. The diode string is parallel or overlapped with the cell string, the diode string is reversely connected in parallel with one or more corresponding cell strings, and the diode is reversely connected in parallel with one or more corresponding cells, where m, n, p, and q are all positive integers, m≥1, n≥2, p≤m, q≤n. For example, m or p can take values such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., and n or q can take values such as 2, 4, 6, 8, 9, 10, 12, 18, 24, 36, 48, 60, 72, etc.

[0030] As Figure 11 shown, the diode string 2 is a special diode string for crystalline silicon photovoltaic modules. Its structure includes a strip-shaped substrate layer 21, on which a plurality of surface-mounted diodes 22 are arranged. For example, it can be a thin-film Schottky diode with a thickness of 279 microns. Its electrical properties are matched with those of photovoltaic cells. The positive and negative poles between adjacent diodes 22 are electrically connected through a conductive layer 23. The positive and negative poles of the two diodes at both ends are also led out through the conductive layer. The conductive layer can be a copper foil, and the width of the conductive layer is less than the width of the substrate layer. Further, the substrate layer 21 is an insulating substrate layer, such as PET, with a width ranging from a few millimeters to dozens of millimeters and a thickness between 30 - 300 microns, preferably between 50 - 200 microns, and more preferably between 100 - 150 microns. A plurality of windows are arranged at intervals in the middle on the insulating substrate layer, enabling the conductive layer 23 on the insulating substrate layer to conduct downward through the windows. The windows are in the shape of rectangles, squares or circles, and the substrate layer material at the windows is not completely removed, but has two substrate blades 211 with a structure similar to two pairs of opening doors. For example, as shown in the figure, it is a rectangular window, cut along the two long sides of the rectangle, retaining the two short sides connected to the substrate layer body, and cut along the midline parallel to the short sides to form two substrate blades 211 with a structure similar to two pairs of opening doors. Then, after the two substrate blades are folded, the conductive layer is pressed below at the same time. When pressure is applied to the two substrate blades at the window, the corresponding conductive layer will bend at the window, so that the conductive layer passes through the window and is coplanar with the back surface of the substrate layer. The substrate layer serves as a support layer, facilitating the production and overall movement of the diode string. At the same time, it has insulating properties to avoid unnecessary electrical contact. When the module is encapsulated, the battery string and the diode string can be clamped between two layers of EVA for lamination. The EVA melts and crosslinks to encapsulate the battery cells and diodes synchronously, perfectly integrating multiple diode strings into a conventional photovoltaic module.

[0031] Example 1

[0032] As Figure 1As shown, in this example, m = 2, n = 4, p = 2, q = 4. The photovoltaic module in this example includes 2 cell strings 1 and 2 diode strings 2. The cell strings 1 and the diode strings 2 are shown in the dashed boxes. Each cell string includes 4 conventional solar cells connected in series with each other, and the 2 cell strings 1 are also connected in series with each other. Each diode string includes 4 diodes connected in series with each other. The diode string is located outside the cell string, and the two are parallel but do not overlap. The photovoltaic module also includes a plurality of regularly arranged conductive tapes 3. A conductive tape 3 is pasted in the middle of the back of each solar cell. The conductive tape 3 is pasted on the back of the solar cell and extends outward for a certain length to be bonded to the EVA film below the solar cell. The conductive tape 3 leads out the positive and / or negative poles of the corresponding solar cell. The conductive tape 3 at one end of the cell string is conductively connected and bonded to the bus bar 4. The diode string 2 is vertically stacked on the conductive tape 3, so that the conductive layer 23 on the diode string is conductively connected to the conductive tape 3 below it through the window 211, realizing the conductive connection between the conductive tape 3 and the negative and positive poles of the corresponding diode. The conductive tape not only leads out the positive and / or negative poles of the corresponding solar cell and conducts electricity with the negative and / or positive poles of the corresponding diode respectively, but also plays a role in bonding and positioning the cell string, preventing the cell string from shifting during subsequent movement or lamination, and can partially or completely replace the use of positioning tapes in the spreading process during the manufacturing process of conventional photovoltaic modules. The circuit diagram of the photovoltaic module in this example is as Figure 2 shown. In this example, 8 solar cells are connected in series, and each solar cell is reversely connected in parallel with a diode, for a total of 8 diodes. When any one solar cell is shaded or damaged, the diode reversely connected in parallel with the solar cell can immediately play a bypass role.

[0033] Embodiment 2

[0034] As Figure 3 shown, in this example, m = 2, n = 4, p = 2, q = 2. This example is similar to Embodiment 1. The photovoltaic module in this example also includes 2 cell strings and 2 diode strings. Each cell string includes 4 solar cells connected in series with each other, and the 2 cell strings are also connected in series with each other. The diode string is located outside the cell string, and the two are parallel but do not overlap. The photovoltaic module also includes a plurality of conductive tapes 3, and their functions are the same as those in Embodiment 1. The difference from Embodiment 1 is that each diode string includes 2 diodes connected in series with each other, and a conductive tape is provided every other solar cell. The circuit diagram of the photovoltaic module in this example is as Figure 4 shown. In this example, 8 solar cells are connected in series, and one diode is reversely connected in parallel for every two series-connected solar cells, for a total of 4 diodes, that is, one diode bypasses and protects two series-connected solar cells, which can reduce the number of diodes. Of course, the configuration of the diodes can be flexibly configured according to needs. For example, when the number of solar cells in each cell string is an integer multiple of three (such as 9 pieces), one reversely connected diode can be shared by every three series-connected solar cells. Of course, a non-uniform method can also be adopted.

[0035] Example 3

[0036] As Figure 5 shown, in this example, m = 2, n = 4, p = 1, q = 4. The photovoltaic module in this example also includes 2 battery strings, and each battery string includes 4 serially connected solar cells. The difference from Example 1 is that: in this example, the 2 battery strings are connected in parallel and share 1 diode string. The diode string is parallel or overlapped with the battery string. In the figure, the shown diode string is located in the middle of the two battery strings, and the three are parallel but not overlapped. The photovoltaic module also includes a plurality of conductive tapes. There are five conductive tapes in total in this example, and their functions are the same as those in Example 1, and the solar cells at corresponding positions in the two battery strings share one conductive tape. The circuit diagram of the photovoltaic module in this example is as Figure 6 shown. One diode is reversely connected in parallel for every two parallel-connected solar cells, and there are 4 diodes in total, that is, one diode bypasses and protects two solar cells, which can also reduce the number of diodes.

[0037] Example 4

[0038] As Figure 7 shown, in this example, m = 2, n = 4, p = 2, q = 4. The photovoltaic module in this example also includes 2 battery strings, and each battery string includes 4 serially connected solar cells. The 2 battery strings are connected in parallel, and the layout of the solar cells is the same as that in Example 3. The difference from Example 3 is that: this example includes 2 diode strings, one battery string corresponds to one diode string, and the diode string and the battery string are arranged in an overlapping manner. Conductive tapes are pasted in the middle of the back of each solar cell in advance before overlapping. The circuit diagram of the photovoltaic module in this example is as Figure 8 shown.

[0039] Example 5

[0040] As Figure 9 shown, in this example, m = 3, n = 4, p = 1, q = 4. The photovoltaic module in this example includes 3 battery strings, and each battery string includes 4 serially connected solar cells. The 3 battery strings are all connected in parallel, and the overall layout is similar to that in Example 3, with one more parallel-connected battery string than in Example 3. The circuit diagram of the photovoltaic module in this example is as Figure 10 shown. One diode is reversely connected in parallel for every three parallel-connected solar cells, and there are 4 diodes in total, that is, one diode bypasses and protects three solar cells, which can also reduce the number of diodes.

[0041] Example 6

[0042] As Figure 13As shown, in this example, m = 2, n = 4, p = 2, q = 4. Two battery strings are connected in series, and the layout of the solar cells is the same as that in Embodiment 1. The difference from Embodiment 1 is that in this example, the diode string is arranged overlapping with the battery string, and the conductive tape 3 is pasted on the interconnection bars 10 at both ends of each solar cell. At the same time, the type of solar cell is a back-contact solar cell. The front side of the back-contact solar cell has no grid lines, and multiple positive grid lines 111 and negative grid lines 112 are arranged in a cross-parallel manner on its back side, as shown in Figure 14 shown. Interconnection bars can be welded on both the positive and negative grid lines. The interconnection bars 10 connect the positive and negative poles of the front and rear solar cells in series. Since both the positive and negative poles exist on the back side of the back-contact solar cell, the conductive tape 3 cannot be arranged on the back side of the solar cell and can only be arranged on the interconnection bars between the solar cells or the interconnection bars at one end thereof. Of course, in this example, the diode string may not overlap with the battery string, but instead, a method similar to that in Embodiment 1 is adopted, that is, the diode string is located outside the battery string.

[0043] Embodiment 7

[0044] When the solar cells in the photovoltaic module adopt the back-contact solar cells as shown in Figure 14 shown, according to the characteristics of the back-contact solar cells, in order to simplify the processes such as the series connection of the solar cells and the pasting of the conductive tape, the structure and manufacturing method of the back-contact photovoltaic module are as follows:

[0045] S1. Prepare the intermediate circuit layer: The structure of the intermediate circuit layer is as shown in Figure 15 shown, including a substrate layer 21. The size of the substrate layer is slightly smaller than the sizes of the front plate and the back plate. Conductive circuits are fabricated on the substrate layer 21 through a screen printing process or a PCB printed circuit board process. The conductive circuits include multiple groups of lead-out wire groups 213 and multiple groups of interconnection wires 214. The layout of the lead-out wire groups 213 on the substrate layer is consistent with the series-parallel layout of the solar cells. Four solar cell positioning marks 218 are arranged around each group of lead-out wire groups 213 to facilitate the positioning and placement of the solar cells. Each group of lead-out wire groups 213 includes multiple positive lead-out wires 2131 and negative lead-out wires 2132. The multiple positive and negative lead-out wires shown in the figure are arranged in parallel at intervals. The positive and negative lead-out wires of each group of lead-out wire groups can be matched with the positive and negative grid lines of a back-contact solar cell. The positive and negative lead-out wires of adjacent lead-out wire groups 213 are connected through a group of interconnection wires 214 to form a lead-out wire group string. The two ends of the lead-out wire group string are also connected to the bus bars 215 through interconnection wires 214. Drain wires 216 are connected to each group of interconnection wires 214. Diode connection terminals 217 are provided between adjacent drain wires 216; the conductive circuits also include component positive and negative connection terminals 219; the layout of the conductive circuits determines the series-parallel connection method between the solar cells in the final photovoltaic module;

[0046] S2. Place the solar cells and diodes on the above intermediate circuit layer: As shown in Figure 16As shown, first, according to the positioning identifier 218, the back-contact solar cells 11 are placed in alignment on each set of lead-out wire groups 213. The grid lines of the solar cells face downward, and the non-grid line surface (light-receiving surface) faces upward. The positive and negative grid lines of the solar cells are conductively and fixedly connected to the positive and negative lead-out wires below them by welding or bonding. Then, diodes 22 are conductively and fixedly connected to each diode connection terminal 217 to form a diode string, and each diode is reversely connected in parallel with its corresponding solar cell. Finally, the positive and negative lead wires of the module are conductively and fixedly connected to the positive and negative connection terminals 219 of the module.

[0047] S3. Laminating and co-laminating: Lay the backsheet flat on a horizontal tabletop, lay the second encapsulant layer flat on the backsheet, lay the intermediate circuit layer with the solar cells and diodes connected in the above S2 flat in the center of the second encapsulant layer, lay the first encapsulant layer on the intermediate circuit layer, lay the transparent front plate on the first encapsulant layer, and lead out the positive and negative lead wires of the module from the front plate or the backsheet to obtain a laminated piece; when the front plate is a relatively heavy glass, the above lamination sequence can also be reversed, that is, the front plate, the first encapsulant layer, the intermediate circuit layer, the second encapsulant layer, and the backsheet are placed in sequence, and the light-receiving surface of the solar cell faces the front plate; the sizes of the backsheet, the front plate, the first encapsulant layer, and the second encapsulant layer are basically matched, and the size of the substrate layer is slightly smaller than theirs. For example, the periphery of the substrate layer is 10-20 mm smaller than the first encapsulant layer and the second encapsulant layer. Finally, the laminated piece is sent into a high-temperature vacuum laminator for lamination. After the two encapsulant layers are melted and integrated into one body to remain transparent, the substrate layer, the solar cells, and the diodes are wrapped, and the front plate and the backsheet are bonded into a whole. Of course, for the aesthetic appearance of the final module, a shielding sheet can also be covered on the diode string in the laminated piece. The color of the shielding sheet is consistent with the substrate layer and the backsheet, and the shielding sheet is also wrapped by the encapsulant layer. In this way, the diodes cannot be seen on the front side of the photovoltaic module after lamination. Finally, after trimming and installing the junction box, the back-contact photovoltaic module configured with bypass diodes is obtained. In this example, m = 2, n = 4, p = 2, and q = 4.

[0048] In the above embodiments, without changing the layout of the existing photovoltaic module or minimizing the layout changes, the diode string can be encapsulated inside the photovoltaic module to realize the parallel bypass diodes for all the solar cells or the specified part of the solar cells in the photovoltaic module, which significantly improves the reliability of the photovoltaic module.

Claims

1. A photovoltaic module configured with multiple bypass diodes, comprising a front plate and a back plate, characterized in that, Between the front plate and the back plate, m battery strings and p diode strings are encapsulated through an interlayer. Each battery string includes n series-connected conventional crystalline silicon solar cells, and each diode string includes q series-connected bypass diodes. The n solar cells are aligned in the same orientation in a straight line, and the q bypass diodes are aligned in the same orientation in a straight line. The diode string is parallel or overlapped with the battery string, the diode string is reversely connected in parallel with one or more corresponding battery strings, and the diode is reversely connected in parallel with one or more corresponding solar cells, where m, n, p, and q are all positive integers, m≥1, n≥2, p≤m, and q≤n.

2. The photovoltaic module configured with a plurality of bypass diodes according to claim 1, wherein The diode string includes a substrate layer, and a plurality of the diodes are arranged on the substrate layer. The positive and negative electrodes between adjacent diodes are conductively connected through a conductive layer, and the positive and negative electrodes of the two diodes at both ends are also led out through the conductive layer.

3. The photovoltaic module configured with multiple bypass diodes according to claim 1, wherein The photovoltaic module further includes a plurality of conductive tapes, and the conductive tapes are adhered to the middle of the back surface of the solar cell, and the conductive tapes lead out the positive and / or negative electrodes of the corresponding solar cell.

4. A photovoltaic module configured with multiple bypass diodes according to claim 2, wherein, The substrate layer is an insulating substrate layer, and a plurality of windows are arranged on the insulating substrate layer, and the windows can conduct the conductive layer on the insulating substrate layer downward.

5. A photovoltaic module configured with multiple bypass diodes according to claim 1, wherein, m or p can take 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and n or q can take 2, 4, 6, 8, 9, 10, 12, 18, 24, 36, 48, 60, 72.

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