A photovoltaic module with multiple bypass diodes and a method of manufacturing the same

Abstract

The application provides a photovoltaic module with multiple bypass diodes and a preparation method thereof, and belongs to the technical field of photovoltaic modules; in the application, the photovoltaic module with multiple bypass diodes reversely biases a diode between every adjacent two parallel positions or a plurality of parallel positions; the photovoltaic module with multiple bypass diodes reduces the number of battery pieces controlled by the bypass diodes by connecting a plurality of bypass diodes in parallel, thereby reducing the hot spot risk of the photovoltaic module; the photovoltaic module with multiple bypass diodes has simple circuit connection, simple and convenient preparation method and good application advantages.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photovoltaic modules, and particularly relates to a photovoltaic module with multiple bypass diodes and a preparation method thereof. BACKGROUND

[0002] The material of the photovoltaic module is a crystalline silicon photovoltaic cell, which is a large-area sheet-shaped semiconductor device, and the front and back surfaces are respectively two electrodes of the cell. Under irradiation conditions, the cell has low voltage and high current electrical performance characteristics, and is the smallest unit body of solar power generation. The working voltage of the crystalline silicon photovoltaic cell is about 0.6v, and the maximum working current can reach 10A or even more than 15A. In the prior art, the cell is packaged and protected and laid out in series to form a photovoltaic module, so that the working voltage of the module is increased while the current is not too large.

[0003] However, the current flowing through all the series devices must be consistent when the cell is packaged and protected and laid out in series to form a photovoltaic module. Due to the fact that the photo-generated current generated by different cells in a module is not completely consistent, and in the long-term use in outdoor environment, there are various reasons such as cloud, tree shadow, surface dirt, etc. that make the light intensity received by the cell not completely consistent, thereby causing the current mismatch between the cells in the module. The low-current cell causes the overall current of the module to decrease, and the cell is partially or completely loaded to consume power, and at the same time the temperature of the cell rises sharply, which may cause circuit damage, module burning, fire, etc. To avoid the above problems, a reverse bypass diode is connected in parallel in the module, and when current mismatch occurs, the current can flow through the bypass diode in time to bypass the low-current cell. The conventional photovoltaic module is connected in parallel with three bypass diodes, each bypass diode is connected in parallel with a reverse bias of a cell string, and the more the number of cells connected in series in the cell string, the greater the risk of hot spot of the photovoltaic module. In addition, in the conventional module, two adjacent cell strings are generally connected in series, and the line connection is complex and difficult to manufacture. Therefore, it is necessary to provide a photovoltaic module with multiple bypass diodes, which has low hot spot risk and is simple to manufacture. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a photovoltaic module with multiple bypass diodes and a preparation method thereof. In the present application, the photovoltaic module with multiple bypass diodes is connected in series and parallel on the basis of the cell array, and a diode is connected in parallel between every two adjacent parallel positions or a plurality of parallel positions; the photovoltaic module with multiple bypass diodes reduces the number of cells controlled by the bypass diode by connecting multiple bypass diodes in parallel, thereby reducing the risk of hot spot of the photovoltaic module; the line connection of the photovoltaic module with multiple bypass diodes is simple, the preparation method is simple and convenient, and has good application advantages.

[0005] The present application achieves the above technical purposes through the following technical means.

[0006] A photovoltaic module with multiple bypass diodes, comprising a front cover, a front adhesive film, a cell layer, a back adhesive film and a back cover; the cell layer comprises a cell string group and a bypass diode;

[0007] The cell string group comprises m parallel cell strings; the cell string comprises n series of split cell pieces; wherein m≥2, n≥2;

[0008] The bypass diode is connected in parallel with the split cell piece or the cell string in reverse bias.

[0009] Further, the m parallel cell strings are welded in parallel, so that the split cell piece is in series with the front and rear split cell pieces and in parallel with the split cell pieces on both sides; the welding position is connected with a parallel position welding strip.

[0010] Further, the split cell piece is obtained by equally dividing the whole photovoltaic cell along the direction perpendicular to the series connection.

[0011] Further, the two ends of the split cell piece in the cell string each have a parallel position, and the two ends of the bypass diode are reversely connected in parallel with any two parallel positions; at least three bypass diodes are connected in parallel in the cell string.

[0012] Further, the parallel positions connected by the two ends of the bypass diode are respectively welded with a parallel position welding strip, and the parallel position welding strip is welded with a lead-out wire welding strip, and the lead-out wire welding strip passes through the back adhesive film and the back cover. Further, at least one bypass diode is reversely connected in parallel between each two parallel positions.

[0013] Further, the bypass diode is packaged into a diode box, the length of the diode box is equivalent to the length of the photovoltaic module, and the width of the diode box is equivalent to the spacing between the cell strings, and the diode box is pasted on the back of the back cover.

[0014] Further, the diode box comprises at least one bypass diode, the bypass diode is respectively provided with a lead-out wire welding post at both ends, and the lead-out wire welding post is provided with a lead-out wire insertion hole; the lead-out wire insertion hole is connected with the lead-out wire welding strip penetrating into the diode box body.

[0015] The present application also provides a preparation method of the above-mentioned photovoltaic module with multiple bypass diodes, which specifically comprises the following steps:

[0016] (1) equally divide the whole photovoltaic cell along the direction perpendicular to the series connection, divide it into several split cell pieces of the same size, then manufacture the cell string by series connection with the several split cell pieces, and weld the parallel position welding strip on the parallel position where the bypass diode is needed;

[0017] (2) sequentially and side by side parallel connect the battery strings in step (1), and parallel weld the slitting battery pieces in the same position of all the battery strings by connecting the parallel position welding ribbons to obtain a battery string group;

[0018] Reverse bias and parallel connect the battery strings in the battery string group or the slitting battery pieces in series in the battery string with the bypass diode to obtain a battery layer;

[0019] (3) sequentially place the front cover plate, the front adhesive film, the battery layer, the back adhesive film and the back cover plate, complete laminated packaging, then install the junction box and the frame, and obtain the photovoltaic module after solidification.

[0020] Further, in step (2), the preparation step of the battery layer is: welding the lead-out wire ribbons on the parallel position welding ribbons in the battery string group, then punching holes at the corresponding positions of the back adhesive film and the back cover plate corresponding to the lead-out wire ribbons, and the lead-out wire is pulled out from the hole, and the two ends of the bypass diode are connected with any two lead-out wire ribbons.

[0021] Further, the bypass diode is installed in the diode box, and the lead-out wire is connected with the lead-out wire insertion hole on the lead-out wire post on the two ends of the bypass diode by penetrating into the box body outer wall of the diode box.

[0022] Further, the material of the diode box body is preferably stainless steel or aluminum alloy.

[0023] The photovoltaic module with multiple bypass diodes in the application connects multiple bypass diodes in parallel, which reduces the number of battery pieces controlled by the bypass diode. Therefore, when the battery piece current is mismatched, the current can flow through the bypass diode of the mismatched battery in time, without affecting the normal power generation of the remaining battery pieces in the module, and the reverse voltage of the mismatched battery is low, the consumed power is small, and the battery temperature will not rise too high. In addition, the parallel design of the battery string can make the parallel battery string play a role in shunting when the slitting battery piece is shaded. Therefore, the photovoltaic module with multiple bypass diodes in the application has very low hot spot risk and high power generation under the condition of module shading.

[0024] The parallel connection method of the bypass diode in the photovoltaic module with multiple bypass diodes designed in the application is simple to implement, and the number of bypass diodes that need to be connected in parallel in the module and the number of battery pieces controlled by the bypass diode can be randomly selected. It only needs to connect the lead-out wire on the parallel position between the two ends of the battery piece that needs to be connected in parallel and penetrate to the back of the module, and connect the lead-out wire insertion hole on the corresponding bypass diode in the diode in the back of the module. In addition, at least two bypass diodes can be connected in parallel between each pair of parallel positions or at least two diode boxes can be provided to enhance the shunting capacity of the bypass diode.

[0025] The module back of the photovoltaic module with multiple bypass diodes in the application is provided with a diode box, the box is attached to the module back, and the box is connected with the frame at two ends. The module is installed outdoors, and the box supports the module, thereby improving the wind pressure resistance, snow pressure resistance and load capacity of the module. The box is made of a good thermal conductive material, and the heat generated by the bypass diode can be well transmitted to the bypass diode and the module, thereby maintaining the temperature of the bypass diode and the module. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The circuit diagram (a) and the circuit connection structure schematic diagram (b) of the photovoltaic module cell layer in the application.

[0027] Figure 2 The two different cell piece connection modes are shown, wherein a is that the bypass diode is connected with the lead-out wire welding strip, and b is that the lead-out wire welding strip without the bypass diode is connected.

[0028] Figure 3 The structure schematic diagram in the diode box is shown.

[0029] Figure 4 The schematic diagram of two bypass diodes in parallel on the same parallel position is shown.

[0030] REFERENCE NUMERALS:

[0031] 1 - split cell piece; 2 - parallel position; 3 - parallel position welding strip; 4 - lead-out wire welding strip; 5 - parallel position connection welding strip; 6 - lead-out wire jack; 7 - bypass diode; 8 - lead-out wire welding column; 9 - box DETAILED DESCRIPTION

[0032] The application will be further described in combination with the drawings and specific embodiments, but the protection scope of the application is not limited thereto. Example 1

[0033] The photovoltaic module with multiple bypass diodes in the application comprises a front cover plate, a front adhesive film, a cell layer, a back adhesive film and a back cover plate. Figure 1 As shown in (a), the cell layer comprises a cell string group and a bypass diode, the cell string group comprises m (m≥2) parallel cell strings, and the cell string comprises n (n≥2) split cell pieces 1 in series. The split cell piece 1 is obtained by equally dividing the whole photovoltaic cell along the direction perpendicular to the series connection, the m parallel cell strings are arranged side by side in parallel, so that the split cell piece 1 is connected in series with the front and rear split cell pieces 1 and connected in parallel with the split cell pieces 1 on both sides. The bypass diode 6 is connected in parallel in reverse bias with the split cell piece 1 or the cell string.

[0034] As shown in (b), the cell layer comprises a cell string group and a bypass diode, the cell string group comprises m (m≥2) parallel cell strings, and the cell string comprises n (n≥2) split cell pieces 1 in series. The split cell piece 1 is obtained by equally dividing the whole photovoltaic cell along the direction perpendicular to the series connection, the m parallel cell strings are arranged side by side in parallel, so that the split cell piece 1 is connected in series with the front and rear split cell pieces 1 and connected in parallel with the split cell pieces 1 on both sides. The bypass diode 6 is connected in parallel in reverse bias with the split cell piece 1 or the cell string. Figure 1(a) and 1 (b), the front and rear of the battery piece in the battery string is one parallel position 2, the bypass diode 7 is reversely connected in parallel with any two parallel positions 2, and at least three bypass diodes 7 are connected in parallel in the battery string. In the multi-bypass diode photovoltaic module of the application, at least two parallel positions 2 connected at both ends of the bypass diode 7 are welded with parallel position welding strips 3, the parallel position welding strips 3 are welded with lead-out wire welding strips 4, and the lead-out wire welding strips 4 pass through the back adhesive film and the back cover plate.

[0035] As shown in Figure 2 , the bypass diode 6 can be connected with the lead-out wires on the adjacent two parallel positions 2 or the lead-out wires on any two parallel positions 2 spaced by a certain number. Since one bypass diode can be connected in parallel between every two adjacent lead-out wire welding strips, the number of diodes is large, and the multi-bypass diode photovoltaic module of the application adopts a rectangular box to encapsulate the bypass diode 7 to obtain a diode box as shown in Figure 3 . The length of the diode box is equivalent to the length of the photovoltaic module, and the width is equivalent to the spacing between the battery strings. The diode box is pasted on the back of the back cover plate. The diode box includes a box body, and at least one bypass diode 7 is encapsulated in the box body 9. The bypass diode 7 is provided with a lead-out wire welding stud 8 at both ends, and the lead-out wire welding stud 8 is provided with a lead-out wire insertion hole 6. The lead-out wire insertion hole 6 is connected with the lead-out wire penetrating into the diode box body. The diode box body material is preferably a material with high load strength and good heat dissipation such as stainless steel and aluminum alloy, which can ensure that the bypass diode 7 is encapsulated / connected while supporting the photovoltaic module to some extent, effectively enhancing the load strength of the photovoltaic module, and allowing the heat generated by the bypass diode 7 to be dissipated in time.

[0036] As shown in Figure 4 , in order to enhance the shunt capacity of the bypass diode 7, two or more bypass diodes 7 can be connected in parallel between each pair of parallel positions, and the bypass diode 7 is encapsulated in the diode box. Embodiment 2

[0037] The embodiment provides a preparation method of the multi-bypass diode photovoltaic module of embodiment 1, which specifically includes the following steps:

[0038] (1) The whole photovoltaic cell is cut along the direction perpendicular to the series connection to divide it into several same-size cut battery pieces 1, and then the several cut battery pieces 1 are connected in series to form a battery string, and parallel position welding strips 3 are welded on the parallel positions 2 where the bypass diodes 7 are needed.

[0039] (2) The battery strings in step (1) are connected in parallel in sequence, and the slitting battery pieces 1 in the same position of all the battery strings are connected in parallel by parallel connection welding strips to obtain a battery string group.

[0040] The battery strings in the battery string group or the slitting battery pieces 1 connected in series in the battery string are connected in parallel by reverse biasing and connecting with bypass diodes 7 to obtain a battery layer; the preparation steps of the battery layer are as follows:

[0041] The lead-out wire welding strip 4 is welded on the parallel connection welding strip 3 in the battery string group, then the corresponding back adhesive film and the corresponding position of the back cover plate are holed, the lead-out wire welding strip 4 is led out from the hole, and the two ends of the bypass diode 7 are connected with any two lead-out wire welding strips 4.

[0042] The bypass diode 7 is installed in a diode box, and the lead-out wire is connected with the lead-out wire insertion hole on the lead-out wire welding column at the two ends of the bypass diode through the box body outer wall of the diode box.

[0043] (3) The front cover plate, the front adhesive film, the battery layer, the back adhesive film and the back cover plate are placed in sequence, and the laminated packaging is completed, then the junction box and the frame are installed, and the photovoltaic module is obtained after solidification.

[0044] The embodiments are preferred embodiments of the present application, but the present application is not limited to the above embodiments, and any obvious improvement, replacement or modification made by those skilled in the art without departing from the essential content of the present application shall fall within the protection scope of the present application.

Claims

1. A photovoltaic module with multiple bypass diodes, characterized in that, The photovoltaic module includes a front cover plate, a front encapsulant film, a battery layer, a back encapsulant film, and a back cover plate; the battery layer includes battery strings and bypass diodes (7). The battery string group includes m parallel battery strings; the battery string includes n series-connected split battery cells (1); where m≥2, n≥2; The bypass diode (7) is connected in parallel with the split battery cell (1) or battery string in reverse bias; Each end of the split battery cell (1) in the battery string has a parallel connection (2), and the two ends of the bypass diode (7) are connected in reverse parallel with any two parallel connection (2); at least three bypass diodes (7) are connected in parallel in the battery string. The parallel positions (2) connected to both ends of the bypass diode (7) are respectively welded with parallel position solder strips (3), and lead wire solder strips (4) are welded on the parallel position solder strips (3). The lead wire solder strips (4) pass through the back adhesive film and the back cover plate. The bypass diode (7) is packaged into a diode box. The length of the diode box is equivalent to the length of the photovoltaic module, and the width is equivalent to the spacing between the battery strings. The diode box is pasted on the back of the back cover plate. The diode box includes at least one bypass diode (7), and each of the two ends of the bypass diode (7) is provided with a lead wire welding post (8). The lead wire welding post (8) is provided with a lead wire socket (6). The lead wire socket (6) is connected to the lead wire solder strip (4) that passes through the diode box body (9).

2. The photovoltaic module with multiple bypass diodes according to claim 1, characterized in that, The m parallel battery strings are welded together to form a parallel connection, so that the slit battery cell (1) is connected in series with the slit battery cells (1) in front and behind, and in parallel with the slit battery cells (1) on both sides; the welding point of the series welding is the parallel connection welding strip (5).

3. The photovoltaic module with multiple bypass diodes according to claim 1, characterized in that, The slit solar cell (1) is obtained by dividing the entire photovoltaic cell into equal parts along a direction perpendicular to the series connection.

4. The photovoltaic module with multiple bypass diodes according to claim 1, characterized in that, At least one bypass diode (7) is connected in reverse parallel between every two parallel positions (2).

5. A method for manufacturing a photovoltaic module with multiple bypass diodes according to any one of claims 1 to 4, characterized in that, include: (1) Cut the whole photovoltaic cell equally along the direction perpendicular to the series connection, and divide it into several cut cell pieces (1) of the same size. Then, the several cut cell pieces (1) are connected in series to form a battery string; and the parallel position solder strip (3) is welded on the parallel position (2) where the parallel bypass diode (7) needs to be connected in parallel. (2) The battery strings described in step (1) are connected in parallel in sequence, and the cut battery pieces (1) at the same position of all battery strings are connected in parallel by the parallel connection welding strip (5) to obtain the battery string group. The battery string in the battery string group or the split battery cell (1) connected in series in the battery string is reverse biased and connected in parallel with the bypass diode (7) to obtain the battery layer; The battery layer is prepared by welding lead wires (4) onto the parallel position solder strips (3) in the battery string group, then opening holes at the corresponding positions of the back adhesive film and the back cover plate corresponding to the lead wires (4), and passing the lead wires (4) through the holes to connect the two ends of the bypass diode (7) to any two lead wires (4). The bypass diode (7) is installed inside the diode housing (9), and the lead wire solder strip (4) is inserted into the outer wall of the diode housing (9) and connected to the lead wire socket (6) on the lead wire solder post (8) at both ends of the bypass diode (7); (3) Place the front cover plate, front film, battery layer, back film and back cover plate in sequence to complete the lamination and encapsulation, then install the junction box and frame, and obtain the photovoltaic module after curing.

6. The method for fabricating a photovoltaic module with multiple bypass diodes according to claim 5, characterized in that, The diode housing (9) is made of stainless steel or aluminum alloy.

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