Manufacturing method of back contact photovoltaic module provided with bypass diode

Abstract

The invention discloses a manufacturing method of a back contact photovoltaic module configured with a bypass diode, and the method comprises the following steps: S1, preparing an intermediate circuit layer: the intermediate circuit layer comprises a substrate layer, a conductive circuit is manufactured on the substrate layer, the conductive circuit comprises a plurality of groups of outgoing line groups and a plurality of groups of interconnection lines, each leading-out wire group comprises a plurality of positive leading-out wires and negative leading-out wires, the positive leading-out wires and the negative leading-out wires of the adjacent leading-out wire groups are connected through a group of interconnection wires, each group of interconnection wires is connected with a drainage wire, and a diode connecting terminal is arranged between the adjacent drainage wires; s2, placing a battery piece and a diode on the intermediate circuit layer; and S3, laminating and laminating: flatly laying the back plate, the second laminated layer, the middle circuit layer, the first laminated layer and the transparent front plate on a horizontal table board, and feeding into a high-temperature vacuum laminating machine for laminating. According to the invention, the diode string and the battery string are synchronously packaged in the laminated layer, so that the reliability of the whole photovoltaic module is improved, and the photovoltaic module is convenient to produce and manufacture.

Description

[0001] This application is a divisional application for an invention patent application with an application date of August 26, 2024, application number 202411174155.7, and name “A method for manufacturing a photovoltaic module equipped with multiple bypass diodes”. Technical Field

[0002] The present invention specifically relates to a method for manufacturing a photovoltaic module configured with a plurality of bypass diodes, and belongs to the technical field of solar photovoltaic module manufacturing. Background Art

[0003] Photovoltaic modules are photovoltaic panels with certain voltage and current formed by connecting a certain number of photovoltaic cells in series and parallel in a set order. Traditional photovoltaic modules, such as the 60-panel and 72-panel modules, respectively divide 60 cells and 72 cells into 6 strings of cells, with 10 and 12 cells in each string. On the one hand, all 6 strings of cells are connected in series, and on the other hand, a diode is reversely connected in parallel to each two adjacent strings of cells near the lead-out line, for a total of three diodes. These three diodes and two lead-out lines are integrated together in the junction box of a photovoltaic module. This diode is called a bypass diode in the industry according to its functional properties, because when any one or more cells in the corresponding two strings of cells are damaged or blocked and do not generate electricity or the current is significantly reduced, this diode is turned on, and the current generated by other normal power generation strings will partially or completely pass through the diode. The diode acts as a bypass, which can prevent damaged or blocked cells from becoming a load and heating up and then being damaged, and can reduce the loss of power generation of photovoltaic modules. This conventional photovoltaic module configured with three bypass diodes can be used in large-scale photovoltaic power stations, because the impact of one or more strings of cells in a photovoltaic module not generating electricity on the entire photovoltaic power station is very small, which can be said to be negligible; however, for portable mobile photovoltaic modules used alone outdoors or a small number of modules used in series and parallel, even if one of the cells is damaged, it will affect the power generation output of the entire system. Therefore, it is necessary to connect bypass diodes in parallel to all the cells or a specified part of the cells in the photovoltaic module to improve its reliability. The existing photovoltaic module design cannot meet this requirement, and there is no mature method to integrate all the bypass diodes into the photovoltaic module. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a method for manufacturing a photovoltaic module equipped with a plurality of bypass diodes.

[0005] The technical solution adopted by the present invention is: A method for manufacturing a photovoltaic module configured with a plurality of bypass diodes comprises the following steps: Step 1: Lay the transparent front plate horizontally on a flat surface; Step 2: Lay the first interlayer on the front panel; Step 3: Place multiple battery strings that have been connected in series on the first interlayer, with the light-receiving surface of the battery cells in the battery string facing downward, and perform series or parallel welding of bus bars for the battery strings according to the set layout; Step 4: according to the set layout, use multiple conductive tapes to lead out the positive / negative electrodes of all or part of the battery cells, and bond the conductive tapes to the first interlayer; Step 5, this step includes the following sub-steps: 5.1. Lay a back plate on a flat table, stack a second interlayer on the back plate, place a plurality of diode strings at specific positions on the second interlayer, and fix the diode strings with positioning tape; 5.2, covering the diode string with a release film, and then transferring the entire backplane and the load thereon to a laminator for vacuum high-temperature lamination pre-pressing. After the pre-pressing is completed, the release film is torn off to obtain a backplane pre-pressed part; 5.3, the backplane pre-press is placed upside down on the battery sheet with the conductive tape attached in the above step 4, so that the diode string is vertically overlapped with the plurality of conductive tapes and is electrically connected, and the diode string and the battery string are kept parallel, spaced or overlapped; then the laminate is transferred to a laminator for final lamination to obtain a laminate; Finally, the laminate is trimmed and a junction box is installed to obtain a finished photovoltaic module equipped with multiple bypass diodes.

[0006] Furthermore, the number of battery strings in the finished photovoltaic module is m, and the number of diode strings is p, each battery string includes n battery cells connected in series, each diode string includes q diodes connected in series, the n battery cells are oriented in the same direction and arranged in a straight line, the q diodes are oriented in the same direction and arranged in a straight line, the diode strings are reverse-parallel to the corresponding one or more battery strings, and the diodes are reverse-parallel to the corresponding one or more battery cells, wherein m, n, p, q are all positive integers, m≥1, n≥2, p≤m, q≤n.

[0007] Furthermore, the diode string includes a long strip substrate layer, on which a plurality of diodes are arranged, the positive and negative electrodes of adjacent diodes are conductively connected through a conductive layer, the positive and negative electrodes of the two diodes at both ends are also led out through the conductive layer, the conductive layer is centrally arranged on the substrate layer, and the width of the conductive layer is smaller than the width of the substrate layer.

[0008] Furthermore, the conductive tape in the finished photovoltaic module leads out the positive electrode or negative electrode of the corresponding solar cell and is conductively connected to the negative electrode or positive electrode of the corresponding diode respectively.

[0009] Furthermore, the substrate layer is an insulating substrate layer, and a plurality of windows are centrally arranged at intervals on the insulating substrate layer, and the windows can allow the conductive layer on the insulating substrate layer to be conductive downward.

[0010] Furthermore, in step 5.3, the substrate layer of the diode string vertically overlaps and contacts with the conductive tape, and multiple windows on the substrate layer of the diode string overlap with multiple conductive tapes one by one, and the conductive layer at the windows is electrically connected to the conductive tape.

[0011] Furthermore, the window is a rectangle or a square, the long side of the rectangle is perpendicular to the long side of the substrate layer, the length of the long side of the rectangle is greater than the width of the conductive layer, or the side length of the square is greater than the width of the conductive layer. The substrate layer material at the window is not completely removed, but is cut along the two long sides of the rectangle, leaving the two short sides connected to the substrate layer body, and cut along the center line parallel to the short sides to form two substrate blades similar to two double-door structures. After the two substrate blades are folded, the conductive layer is pressed underneath at the same time.

[0012] Furthermore, the battery cell is a conventional battery cell with positive and negative electrodes located on both sides of the battery cell respectively, and a conductive tape is pasted on the middle of the back side of all or part of the battery cell, and the conductive tape is bonded to the first interlayer.

[0013] Furthermore, the battery cell may be a back contact cell with both positive and negative electrodes located on the back of the battery cell, and conductive tape is pasted on the interconnection strips at both ends of all or part of the battery cells and the interconnection strips between the battery cells, and the conductive tape is bonded to the first interlayer.

[0014] Beneficial effect: The present invention provides a photovoltaic module configured with multiple bypass diodes and a manufacturing method thereof, wherein m battery strings and p diode strings are arranged between the front plate and the back plate of the photovoltaic module through an interlayer packaging, the diode string is parallel to or overlaps with the battery string, the diode string is reversely connected in parallel with the corresponding one or more battery strings, the diode is reversely connected in parallel with the corresponding one or more battery cells, and the diode string and the battery string are synchronously or stepwise packaged in the interlayer of the photovoltaic module and are perfectly combined with each other, thereby improving the reliability of the entire photovoltaic module and facilitating production and manufacturing, when any one or more battery cells in the photovoltaic module are blocked or damaged, there are corresponding bypass diodes to bypass and protect them, thereby minimizing their impact on the power generation output of the photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the photovoltaic module layout in Example 1.

[0016] Figure 2 yes Figure 1 Circuit diagram of the .

[0017] Figure 3 This is a schematic diagram of the photovoltaic module layout in Example 2.

[0018] Figure 4 yes Figure 3 Circuit diagram of the .

[0019] Figure 5 This is a schematic diagram of the photovoltaic module layout in Example 3.

[0020] Figure 6 yes Figure 5 Circuit diagram of the .

[0021] Figure 7 This is a schematic diagram of the photovoltaic module layout in Example 4.

[0022] Figure 8 yes Figure 7 Circuit diagram of the .

[0023] Fig. 9 It is a schematic diagram of the diode string structure.

[0024] Fig.10 This is a schematic diagram of a conventional battery cell structure.

[0025] Fig.11 This is a schematic diagram of the photovoltaic module layout in Example 5.

[0026] Fig.12 It is a schematic diagram of the front plate pre-press in Example 5.

[0027] Fig.13 This is a schematic diagram of the back panel pre-press in Example 5.

[0028] Fig.14 This is a schematic diagram of the photovoltaic module layout in Example 6.

[0029] Fig.15 This is a schematic diagram of the back grid lines on the back side of a back-contact solar cell.

[0030] Fig.16 It is a schematic diagram of the structure of the intermediate circuit layer of Example 7.

[0031] Fig.17 This is a schematic diagram of the connection of the battery cells and diodes on the middle circuit layer of Example 7.

[0032] Markings in the figure: 1 battery string, 2 diode string, 3 conductive tape, 4 bus bar, 5 front plate, 6 back plate, 7 second adhesive film, 8 positioning tape, 9 first adhesive film, 10 interconnection bar, 11 battery cell, 12 positive lead bar, 13 negative lead bar, 21 substrate layer, 22 diode, 23 conductive layer, 211 substrate blade, 212 window, 213 lead wire group, 2131 positive lead wire, 2132 negative lead wire, 214 interconnection wire, 215 bus bar, 216 lead wire, 217 diode connection terminal, 218 positioning mark, 219 component positive and negative connection terminal, 111 positive grid line, 112 negative grid line. DETAILED DESCRIPTION

[0033] In order to better understand the technical solution of the present application, the present application is described in detail in detail below in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work, as well as new embodiments obtained by recombining the features between different embodiments without conflict, all belong to the scope of protection of the present application.

[0034] The structure of conventional crystalline silicon solar photovoltaic modules usually includes a front plate and a back plate, and crystalline silicon photovoltaic cells are encapsulated between the front plate and the back plate through an interlayer. The front plate needs to be light-transmissive and usually uses transparent materials such as glass or other inorganic or organic transparent materials such as ETFE, and the back plate usually uses organic polymer materials such as TPT, etc., and its two sides are respectively an air surface and a bonding surface. The interlayer usually uses two layers of EVA materials that are melt-bonded to each other. The thickness of the two layers can be adjusted, for example, the thickness is 0.5mm. After multiple cells are connected to each other, they are located between the two layers of EVA materials and are temporarily bonded and fixed with positioning tape to prevent the battery string from shifting. Because the distance between cells and between battery strings is very narrow, usually only 2-3mm, positioning tape is needed for temporary fixation before lamination. Then, after high-temperature vacuum lamination, the EVA material undergoes a cross-linking reaction and melts into one, wrapping and fixing the cells and bonding the front plate and the back plate as a whole. Finally, after installing the junction box and the frame, the finished photovoltaic module is obtained.

[0035] This patent is improved on the basis of the existing photovoltaic modules. This patent provides a photovoltaic module equipped with multiple bypass diodes. m battery strings and p diode strings are arranged between the front plate and the back plate through the interlayer packaging. Each battery string includes n series-connected battery cells, and each diode string includes q series-connected bypass diodes. The battery cells are conventional crystalline silicon battery cells, and their structure is as follows: Fig.10As shown, a conventional battery cell 11 includes a front and a back side, corresponding to the positive / negative electrode (or negative electrode / positive electrode) of the battery. Silver grid lines for collecting current are screen-printed on both sides, and a plurality of positive and negative electrode lead interconnection strips are welded on the main grid lines. The back side (rear side) of the battery cell shown in the figure is placed upward and has a positive electrode lead interconnection strip 12, and the front side (light-receiving side) of the battery cell is placed downward and has a negative electrode lead interconnection strip 13; the distinction between the positive and negative polarities on the front and back sides of the battery is related to the manufacturing process of the battery. The size of the battery cell can be a conventional complete square (or a square with chamfered corners) size such as 125*125mm, 156*156mm, 182*182mm, 210*210mm, etc., or a 1 / 2 slice, 1 / 3 slice, 1 / 4 slice, etc. of a square size; n battery cells are aligned in a straight line, the positive and negative electrodes of adjacent battery cells are connected, q bypass diodes are aligned in a straight line, the positive and negative electrodes of adjacent diodes are connected, the diode string is parallel to or overlaps with the battery string, the diode string is reversely connected in parallel with the corresponding one or more battery strings, and the diode is reversely connected in parallel with the corresponding one or more battery cells, wherein m, n, p, q are all positive integers, m≥1, n≥2, p≤m, q≤n; for example, m or p can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc., and n or q can be 2, 4, 6, 8, 9, 10, 12, 18, 24, 36, 48, 60, 72, etc.

[0036] like Fig. 9As shown, the diode string 2 includes a strip-shaped substrate layer 21, on which a plurality of patch diodes 22 are arranged, for example, a thin-sheet Schottky diode, with a thickness ranging from tens to hundreds of microns, for example, 200 microns, whose electrical properties match those of the photovoltaic cell, and are attached and fixed to the substrate layer by means of adhesive, and the positive and negative electrodes between adjacent diodes 22 are conductively connected by a conductive layer 23, which is also attached to the substrate layer by means of adhesive, and the positive and negative electrodes of the two diodes at both ends are also led out by the conductive layer, and the conductive layer can be a metal foil such as a copper foil, which is centrally arranged on the substrate layer, 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, for example, PET can be selected, the width is determined according to actual needs, for example, 10 mm can be selected, and the thickness can be selected from tens to 100 microns or even hundreds of microns, and a plurality of windows 212 are centrally arranged on the insulating substrate layer, and the window shape can be rectangular, square or circular, and the window can make the conductive layer 23 on the insulating substrate layer conduct downward. The window shown in the figure is rectangular, and the substrate layer material at the window is not completely removed, but cut along the two long sides of the rectangle, leaving the two short sides connected to the substrate layer body, and cut along the center line parallel to the short sides, forming two substrate blades 211 similar to two double-door structures, and then the two substrate blades are folded and the conductive layer is pressed underneath at the same time, so that the conductive layer can pass through the window and conduct electricity downward. When the two substrate blades at the window are pressed, the corresponding conductive layer will bend at the window, so that the conductive layer and the back of the substrate layer are coplanar. The substrate layer serves as a supporting layer to facilitate the production and overall movement of the diode string; it also has insulating properties to avoid unnecessary electrical contact. The overall thickness of the diode string is less than 0.5mm. When the component is packaged, the battery string and the diode string can be sandwiched between two layers of EVA for lamination, and electrically connected through conductive tape. The EVA melts and cross-links to simultaneously package the battery cells and diodes, perfectly integrating multiple diodes into conventional photovoltaic components.

[0037] Example 1 like Figure 1As shown, in this example, m=2, n=4, p=2, q=4. The photovoltaic module in this example includes two battery strings 1 and two diode strings 2. The battery strings 1 and the diode strings 2 are shown in the dotted boxes, wherein each battery string includes four battery cells 11 connected in series, and the two battery strings 1 are also connected in series through the bus bar 4. Each diode string includes four diodes connected in series, and the diode strings are located outside the battery strings, and the two are parallel but not overlapping. The photovoltaic module also includes a plurality of regularly arranged long rectangular double-sided conductive tapes 3, one conductive tape 3 is pasted on each battery cell, the conductive tape 3 is pasted on the middle of the back side of the battery cell and extends outward for a certain length to bond with the EVA film below the battery cell, the conductive tape 3 leads out the positive and / or negative electrodes of the corresponding battery cell, the conductive tape 3 at one end of the battery string is conductively connected and bonded to the bus bar 4, the diode string 2 is vertically stacked on the outer end of the conductive tape 3, and the window on the diode string corresponds one by one to the conductive tape below it, after subsequent lamination and compression, the conductive layer 23 on the diode string can be conductively connected to the conductive tape 3 below it through the window 211, thereby realizing the conductive connection between the conductive tape 3 and the negative and / or positive electrodes of the corresponding diode. The conductive tape not only leads out the positive and negative electrodes of the corresponding battery cells and connects them to the negative and positive electrodes of the corresponding diodes, but also plays a role in bonding and positioning the battery cells (strings), which can prevent the battery strings from shifting during subsequent movement or lamination. It can partially or completely replace the use of positioning tape in the paving process of conventional photovoltaic module manufacturing. The circuit diagram of this photovoltaic module is shown in the figure. Figure 2 As shown, in this example, 8 cells are connected in series, and each cell is connected in reverse parallel with a diode, for a total of 8 diodes. When any cell is blocked or damaged, the diode connected in reverse parallel with the cell can immediately act as a bypass.

[0038] Example 2 like Figure 3 As shown, in this example, m=2, n=4, p=2, q=2. This example is similar to Example 1, and the photovoltaic module of this example also includes 2 battery strings and 2 diode strings, wherein each battery string includes 4 battery cells connected in series, and the 2 battery strings are also connected in series. The diode string is located on the outside of the battery string, and the two are parallel but not overlapping. The photovoltaic module also includes a plurality of conductive tapes 3, which have the same function. The difference from Example 1 is that each diode string includes 2 diodes connected in series, and a conductive tape is provided for each battery cell. The circuit diagram of the photovoltaic module in this example is shown in FIG. Figure 4As shown, in this example, 8 cells are connected in series, and one diode is connected in reverse parallel to every two cells connected in series, for a total of 4 diodes, that is, one diode bypasses and protects two cells connected in series, which can reduce the number of diodes. Of course, the configuration of diodes can be flexibly configured as needed. For example, when the number of cells in each battery string is an integer multiple of three (for example, 9 cells), one reverse-parallel diode can be used for every three cells connected in series. Of course, a non-equal distribution method can also be adopted.

[0039] Example 3 like Figure 5 As shown, in this example, m=2, n=4, p=1, q=4. The photovoltaic module of this example also includes 2 battery strings, each of which includes 4 battery cells connected in series. 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 overlapping with the battery string. The diode string shown in the figure is located in the middle of the two battery strings. The three are parallel but do not overlap. The photovoltaic module also includes a plurality of conductive tapes 3. In this example, there are five conductive tapes in total. Their function is the same as in Example 1, and the battery cells in corresponding positions in the two battery strings share one conductive tape. The circuit diagram of the photovoltaic module of this example is shown in FIG. Figure 6 As shown, one diode is connected in reverse parallel to every two parallel-connected solar cells, for a total of four diodes, that is, one diode bypasses and protects two solar cells, which can also reduce the number of diodes.

[0040] Example 4 like Figure 7 As shown, in this example, m=2, n=4, p=2, q=4. In this example, the photovoltaic module also includes 2 battery strings, wherein each battery string includes 4 battery cells connected in series, and the 2 battery strings are connected in parallel, and the layout of the battery cells is the same as 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 overlapping. Conductive tape is affixed to each battery cell in advance before overlapping, which plays both a conductive role and a positioning role. The circuit diagram of the photovoltaic module in this example is shown in Figure 8 shown.

[0041] Example 5 like Fig.11 As shown, in this example, m=2, n=4, p=2, q=4. The battery string and diode string in this example are consistent with those in Example 1, and the circuit diagram thereof is referred to as Figure 2 , which is different from Embodiment 1 only in that the diode string and the battery string are arranged overlappingly.

[0042] Example 6 like Fig.14As shown, in this example, m=2, n=4, p=2, q=4. The layout of the battery string and the diode string in this example is the same as that in Example 5, both of which are arranged in an overlapping manner; the difference between this example and Example 5 is that the conductive tape 3 is pasted on the interconnection bar 10 between the battery cells and on the intersection of the interconnection bar 10 and the bus bar 4 of the battery cells at both ends of the battery string; this method of pasting the conductive tape can be applied to Fig.10 The conventional battery cell shown in the figure (the two sides of the battery cell are positive and negative), and it is also compatible with Fig.15 The back contact cell shown, Fig.15 The front side (light receiving side) of the back contact cell shown has no grid lines, and there is no light shielding. On the back side, multiple positive grid lines 111 and multiple negative grid lines 112 are arranged in parallel and crosswise, that is, the positive and negative grid lines of the back contact cell are arranged on the back side of the cell at the same time. By welding interconnection bars on the grid lines, the positive and negative electrodes can be led out respectively. Therefore, the conductive tape cannot be directly pasted on the back side of the cell, otherwise it will short-circuit. The conductive tape can only be pasted on the interconnection bars between the cells. For photovoltaic modules using back contact cells, the layout between the diode string and the battery string can also adopt a parallel but non-overlapping manner similar to that shown in Example 1.

[0043] The integrated packaging manufacturing method of the photovoltaic assembly configured with multiple bypass diodes described in the above embodiments 1-6 is as follows: Step 1: Lay the transparent front plate horizontally on a flat surface; Step 2: Lay the first interlayer on the front panel; Step 3: Place multiple battery strings with multiple battery cells connected in series on the first interlayer, with the light-receiving surface of the battery cells in the battery string facing downward, and perform series or parallel welding of bus bars for the battery strings according to the set layout; Step 4: Use multiple conductive tapes to lead out the positive / negative electrodes of all or part of the battery cells according to the set layout; for example, for conventional battery cells, conductive tapes may be pasted on the middle of the back of all or part of the battery cells, and the conductive tapes are bonded to the first interlayer; for back-contact battery cells, conductive tapes may be pasted on both ends of the battery cells and on the interconnection strips between the battery cells, and the conductive tapes are bonded to the first interlayer; Step 5, placing multiple diode strings according to the set layout, the substrate layer of the diode string and the conductive tape are vertically overlapped, contacted and electrically connected, and the conductive layer at multiple windows on the substrate layer of the diode string is overlapped, contacted and electrically connected with multiple conductive tapes one by one, and the diode string and the battery string are kept parallel, spaced or overlapped; Step 6: Lay the second interlayer and the back sheet in sequence, with the adhesive surface of the back sheet facing downward and in contact with the second interlayer, and the air surface of the back sheet facing upward. If necessary, the positive and negative leads of the battery string can be led out from the back sheet or the front sheet to obtain a laminated component. Step 7, transferring the above-mentioned laminated part to a vacuum high-temperature laminator for lamination to obtain a laminated part; Step 8, after trimming the laminate, install the frame, and install the junction box at the positive and negative leads on the back panel or the front panel, so as to obtain a finished photovoltaic module with multiple bypass diodes, and no diodes are required in the junction box.

[0044] When the above-mentioned integrated packaging manufacturing method is used to produce the components shown in Examples 1-6, the problem that multiple cells need to be equipped with bypass diodes is solved; however, for Examples 1-3, since the diode string and the cell string are spaced in parallel and do not overlap, the diode string needs to occupy a certain space area. Under the premise that the layout of the photovoltaic module cells remains unchanged, this will lead to an increase in the size of the photovoltaic module, a decrease in the efficiency of the module, and poor compatibility with conventional photovoltaic modules; therefore, in order to maintain the size of a conventional photovoltaic module, it is best to adopt a method similar to Examples 4-6, that is, placing the diode string and the cell string in parallel and overlapping, but this may lead to new problems, because the substrate layer, conductive layer, and diode that make up the diode string all have a certain thickness, and the diode also has a certain hardness. Stacking them on the crystalline silicon cell may cause the crystalline silicon cell to rupture or produce hidden cracks during the subsequent lamination process, which has certain potential risks.

[0045] In order to solve the problem that the overlapping diode strings may cause the crystalline silicon cell to break or crack, the following backplane pre-pressing method can be adopted: Modify steps 5-7 in the above manufacturing method as follows: 5.1, such as Fig.13 , a back plate 6 is laid on a flat table surface, with the air side of the back plate facing downward and the adhesive side of the back plate facing upward, a second interlayer 7 is stacked on the back plate, and a plurality of diode strings 2 are placed at specific positions on the second interlayer, with the conductive layer and the diodes of the diode strings facing downward and the substrate layer facing upward, exposing a plurality of windows 211 arranged on the substrate layer, and a positioning tape 8 can also be used to fix the substrate layer of the diode string to prevent its position from deviating, and the position of the window 211 should be avoided when pasting the positioning tape 8; 5.2, cover the diode string with a release film, then transfer the entire backplane and its carrier to a laminator for vacuum high-temperature pre-pressing. After the pre-pressing is completed, tear off the release film to obtain a backplane pre-pressed part, such as Fig.13 As shown; in this process, the back plate and the diode string are bonded into a whole by using the second interlayer, so that the diode string is embedded in the second interlayer, and the substrate layer and the second interlayer are coplanar and maintain a certain flexibility, while the conductive layer is exposed through the window; 5.3, the backplane pre-press is placed upside down on the cell sheet with the conductive tape attached in the above step 4, so that the air side of the backplane faces upwards, and the conductive layer at the window is in electrical contact with the conductive tape below, and then the laminate is transferred to a laminator for lamination; Finally, the aforementioned step 8 is performed to complete the production of the photovoltaic module. In the finished photovoltaic module, there is almost no hidden cracking of the cell caused by the diode string.

[0046] When the above-mentioned photovoltaic module manufacturing method is adopted, it is required that the first adhesive film and the second adhesive film are made of the same material, such as any one of EVA, POE, EPE, PVB, SGP and the like. When EVA is adopted, in order to control the consistency of the crosslinking degree of the first adhesive film and the second adhesive film, a photovoltaic module step-by-step packaging manufacturing method can also be adopted, that is, a front plate pre-pressing method is added after step 4 of the above-mentioned manufacturing method, that is, a release film is covered on the battery sheet with positive and negative electrodes led out by conductive tape, and then the front plate and the carrier thereon are transferred to a laminator for pre-pressing and laminating, and the release film is torn off after lamination to obtain a front plate pre-pressing part, such as Fig.12 As shown; adjust the lamination process parameters to control the cross-linking degree of EVA in the front plate prepress and the back plate prepress to be consistent, for example, both are about 40%; then put the back plate prepress upside down on the front plate prepress, align it up and down, so that the conductive layer through the window in the back plate prepress is in contact with the conductive tape in the front plate prepress for conductive connection, and if necessary, conductive glue can be applied to the corresponding position of the window to achieve reverse parallel connection between the diode string and the battery string; if necessary, the positive and negative leads on the front plate prepress can be passed through the back plate prepress; finally, the laminated front plate prepress and back plate prepress are sent to the laminator for lamination again, and the cross-linking degree of EVA is controlled to finally reach about 85%-90%, and the final bonding of the front plate prepress and the back plate prepress is completed, and finally the junction box is installed, and whether to install the frame can be determined according to actual needs; the production of the entire photovoltaic module is completed at this point. The process adopted here is to first laminate and package the battery string and diode string into the front plate pre-press and back plate pre-press respectively, and then laminate and package them together. Experiments have shown that the cross-linking degree of the front and back films of the modules manufactured by this step-by-step packaging method is basically the same, the packaging reliability is basically the same as the integrated packaging method, and there is no obvious cracking or hidden cracking of the cells in the photovoltaic module.

[0047] Example 7 When the cells in the photovoltaic module are Fig.15 When the back contact cell is shown, according to the characteristics of the back contact cell, in order to simplify the processes of connecting the cells in series and pasting the conductive tape, the structure and manufacturing method of the back contact photovoltaic module with the bypass diode can also be as follows: S1. Prepare the intermediate circuit layer: The intermediate circuit layer structure is as follows: Fig.16As shown, it includes a substrate layer 21, and the substrate layer material can be selected from the aforementioned PET or glass fiber board FR4, etc. The size of the substrate layer is slightly smaller than the size of the front plate and the back plate. A conductive circuit is made on the substrate layer 21 by screen printing or PCB printed circuit board technology. The conductive circuit includes multiple groups of lead wire groups 213 and multiple groups of interconnection wires 214. The layout of the lead wire groups 213 on the substrate layer is consistent with the series-parallel layout of the battery cells. Four battery cell positioning marks 218 are set around each group of lead wire groups 213 to facilitate the positioning and placement of the battery cells. Each group of lead wire groups 213 includes multiple positive lead wires 2131 and negative lead wires 2132. The multiple positive and negative lead wires shown are arranged in parallel and at intervals and cross-arranged. The positive and negative lead wires of each lead wire group can match the positive and negative grid lines of a back-contact battery cell. The positive and negative lead wires of adjacent lead wire groups 213 are connected by a group of interconnection wires 214 to form a lead wire group string. The two ends of the lead wire group string are also connected to the bus bar 215 through the interconnection wires 214. A drainage line 216 is connected to each group of interconnection wires 214, and a diode connection terminal 217 is provided between adjacent drainage lines 216; the conductive circuit also includes a positive and negative connection terminal 219 of the component; the layout of the conductive circuit determines the series and parallel connection mode between the battery cells in the final photovoltaic component.

[0048] S2. Place the battery cells and diodes on the intermediate circuit layer: Fig.17 As shown, first, align the back-contact battery cell 11 on each lead wire group 213 according to the positioning mark 218, with the grid line surface of the battery cell facing downward and the non-grid line surface (light-receiving surface) facing upward, and use welding or bonding to make the positive and negative grid lines of the battery cell and the positive and negative lead wires below them conductively fixedly connected; then, conductively and fixedly connect the diode 22 to each diode connection terminal 217, and after connecting multiple diodes, form a diode string, and make each diode reversely connected in parallel with its corresponding battery cell; finally, fix the positive and negative leads of the component to the positive and negative connection terminals 219 of the component.

[0049] S3, stacking and laminating: lay the backplane on the horizontal surface, lay the second interlayer on the backplane, lay the intermediate circuit layer connected with the battery cell and the diode in S2 in the center of the second interlayer, lay the first interlayer on the intermediate circuit layer, lay the transparent front plate on the first interlayer, and lead the positive and negative leads of the component out of the front plate or the back plate to obtain a stacked component; when the front plate is a heavy glass, in order to prevent the battery cell from being crushed, the stacking order can also be reversed, that is, the front plate, the first interlayer, the intermediate circuit layer, the second interlayer, and the back plate are placed in sequence, and the light-receiving surface of the battery cell is kept facing the front plate; wherein the size of the back plate, the front plate, the first interlayer, and the second interlayer is The sizes of the substrate layer of the intermediate circuit layer are basically the same, while the size of the substrate layer is slightly smaller than their sizes. For example, the substrate layer is 10-20mm smaller than the first and second adhesive layers on all sides. Finally, the laminate is sent to a high-temperature vacuum laminator for lamination. The two interlayers are melted and integrated to maintain transparency and wrap the substrate layer, battery cells, and diodes, and the front plate and back plate are bonded as a whole. Of course, in order to make the final component look beautiful, a shielding sheet can also be covered on the diode string in the laminate. The color of the shielding sheet is consistent with that of the substrate layer and the back plate, and the shielding sheet is also wrapped by the interlayer. In this way, the diode cannot be seen on the front of the photovoltaic module after lamination. Finally, after trimming and installing the junction box, the back-contact photovoltaic module with bypass diode is obtained.

Claims

1. A method for manufacturing a back-contact photovoltaic module equipped with a bypass diode, characterized in that: The steps include: S1. Prepare an intermediate circuit layer: the intermediate circuit layer includes a substrate layer, and a conductive circuit is made on the substrate layer. The conductive circuit includes multiple groups of lead wires, multiple groups of interconnection wires, and positive and negative connection terminals of the components. Each group of lead wires includes multiple positive lead wires and negative lead wires. The positive and negative lead wires of each group of lead wires can match the positive and negative grid lines of a back contact battery cell. The positive and negative lead wires of adjacent lead wire groups are connected by a group of interconnection wires to form a lead wire group string. Both ends of the lead wire group string are also connected to the bus bar by interconnection wires. Each group of interconnection wires is connected to a drain wire, and a diode connection terminal is provided between adjacent drain wires. S2, placing cells and diodes on the above-mentioned intermediate circuit layer: first, aligning and placing back-contact cells on each lead wire group, with the grid line side of the cells facing downward and the non-grid line side facing upward, and making the positive and negative grid lines of the cells conductively and fixedly connected to the positive and negative lead wires below them; then, conductively and fixedly connecting diodes to each diode connection terminal, after connecting multiple diodes to form a diode string, and making each diode reversely connected in parallel with its corresponding cell; finally, fixing and conductively connecting the positive and negative lead wires of the assembly to the positive and negative connection terminals of the assembly; S3, stacking and laminating: lay the backplane on a horizontal surface, lay the second interlayer on the backplane, lay the intermediate circuit layer connected with the cells and diodes in S2 in the center of the second interlayer, lay the first interlayer on the intermediate circuit layer, lay the transparent front panel on the first interlayer, and lead the positive and negative leads of the component out of the front panel or the back panel to obtain a stacked component; finally, send the stacked component to a high-temperature vacuum laminator for lamination, and after trimming and installing a junction box, a back-contact photovoltaic component with a bypass diode is obtained.

2. The method for manufacturing a back-contact photovoltaic module equipped with a bypass diode according to claim 1, characterized in that: The stacking order of the stacked components in S3 may also be as follows: placing the front plate, the first interlayer, the middle circuit layer, the second interlayer, and the back plate in sequence, and keeping the light-receiving surface of the battery cell facing the front plate.

3. The method for manufacturing a back-contact photovoltaic module equipped with a bypass diode according to claim 1, characterized in that: The substrate layer of the intermediate circuit layer has a smaller size than the first adhesive layer and the second adhesive layer.

4. The method for manufacturing a back-contact photovoltaic module equipped with a bypass diode according to claim 1, characterized in that: A shielding sheet is covered on the diode string in the laminate, the color of the shielding sheet is consistent with the substrate layer and the backplane, and the shielding sheet is also wrapped by the interlayer.

5. The method for manufacturing a back-contact photovoltaic module equipped with a bypass diode according to claim 1, characterized in that: The substrate layer material is PET or glass fiber board FR4.

6. The method for manufacturing a back-contact photovoltaic module with a bypass diode according to claim 1, characterized in that: Four battery cell positioning marks are set around each lead wire group.

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