Photovoltaic module with hidden bus bar

Abstract

The utility model provides a photovoltaic module with a hidden bus bar, which comprises the bus bar arranged on at least one battery piece of adjacent battery pieces in two adjacent battery strings in a Y direction, and / or the bus bar arranged on at least one battery piece of adjacent battery pieces at two ends of an X direction of the two adjacent battery strings in the Y direction, the second solder strip is electrically connected with the first solder strip and insulated from the second solder strip, or is connected with the second solder strip and insulated from the first solder strip; the bus bar comprises a bus bar main body and a plurality of extension parts arranged at intervals along the extension direction of the main body, the extension direction of the extension parts is perpendicular to the main body, and two ends of the extension parts extend out of the main body; the bus bar further comprises an insulating layer arranged between the bus bar and the battery piece, the insulating layer extends in the direction of the bus bar body, the width of the insulating layer is larger than that of the bus bar body, the insulating layer does not exceed the extending part in the width direction, the bus bar body, the battery piece and the welding strip are isolated through the insulating layer, and the extending part extends out of the insulating layer, is located above the electric connection welding strip and is welded.

Description

Technical Field

[0001] The present application relates to a photovoltaic module with a hidden bus bar, belonging to the technical field of photovoltaic modules. Background Art

[0002] In the prior art, multiple back-contact solar cells are formed into a photovoltaic cell module through steps such as series soldering or full-panel soldering, lamination, and encapsulation of the module. Among them, the photovoltaic cell module includes multiple cell strings, and two cell strings are connected in parallel through a bus bar. The bus bar in the prior art is arranged in the gap area between the cell string groups or in the gap area on one side of the cell string group. Refer to Figure 10 Schematic diagram of a photovoltaic module in the prior art; due to the existence of the gap area, the bus bar can also be seen from the front of the photovoltaic module, affecting the aesthetics; moreover, the existence of the gap area also occupies the space of the photovoltaic module and squeezes the area of the solar cells. Summary of the Utility Model

[0003] The purpose of the present application is to solve at least one of the problems in the prior art, and provide a photovoltaic module with a hidden bus bar, and the photovoltaic module with a hidden bus bar provided by the present application has no problem of desoldering.

[0004] Specifically, a photovoltaic module with a hidden bus bar is provided, including multiple cell strings. Each of the multiple cell strings includes multiple solar cells connected in series along the X direction, and the multiple cell strings are arranged along the Y direction on the photovoltaic module. The solar cells include alternately arranged first grid lines and second grid lines of opposite genders on the back. The first grid lines are connected through first solder tapes, and the second grid lines are connected through second solder tapes. In a cell string, two adjacent solar cells are connected through a first solder tape or a second solder tape; it also includes a bus bar, and the bus bar is arranged on at least one solar cell among adjacent solar cells of two adjacent cell strings in the Y direction, and / or the bus bar is arranged on at least one solar cell among adjacent solar cells at both ends in the X direction of two adjacent cell strings in the Y direction; the bus bar includes a bus bar main body and multiple extension parts arranged at intervals along the extension direction of the bus bar main body. The extension direction of the extension part is perpendicular to the extension direction of the bus bar main body, and both ends of the extension part extend out of the bus bar main body; an insulating layer is also provided between the bus bar and the solar cell. The insulating layer extends along the extension direction of the bus bar main body. The width of the insulating layer is not less than the width of the bus bar main body, and it does not exceed the extension part in the width direction. The insulating layer isolates the bus bar main body from the solar cell, the first solder tape, and the second solder tape. The extension part extends out of the insulating layer and is welded to the corresponding solder tape.

[0005] More specifically, the extension part and the bus bar are integrally formed, or the extension part is arranged on the upper part or the lower part of the bus bar main body.

[0006] More specifically, the extension part is welded to the bus bar main body.

[0007] More specifically, the width of the bus bar body is 3 to 20 mm.

[0008] More specifically, the length that the extension part extends out of the insulating layer is 1 to 60 mm, and the width of the extension part is 0.1 to 4 mm.

[0009] More specifically, the length of the insulating layer is greater than the length of the bus bar body.

[0010] More specifically, the width of the extension part is 0.5 to 4 times the width of the electrically connected solder tape.

[0011] More specifically, in a string of battery strings, the distance between adjacent solar cells is zero distance, or they are stacked with negative distance.

[0012] More specifically, when adjacent solar cells are stacked with negative distance, for one solar cell, one side is located below the adjacent solar cell, and the other side is located above another adjacent solar cell. The stacking size of adjacent solar cells is 0.2 to 0.5 mm.

[0013] More specifically, the solar cell is a main-gridless back-contact solar cell.

[0014] More specifically, the bus bar body extends along the Y direction.

[0015] The photovoltaic module with a hidden bus bar proposed in this application has the following beneficial effects:

[0016] The photovoltaic module with a hidden bus bar of this application reduces or eliminates the gap area between battery strings, arranges the bus bar above a row of batteries in the battery string group, and the bus bar at both ends or in the middle cannot be seen from the front of the photovoltaic module. The module is beautiful and can effectively utilize the area of the photovoltaic module.

[0017] For the photovoltaic module with a hidden bus bar of this application, the bus bar includes a main body and an extension part extending outwards. Only the extension part corresponding to the solder tape is welded to the grid line of the solar cell. Compared with the method of welding the bus bar main body to the grid line of the solar cell, the required welding energy is low, and the technical problem of the solder tape being detached from the grid line of the solar cell caused by the high welding energy of the bus bar main body can be effectively avoided; at the same time, the adverse impact of the height difference brought by the insulating layer under the bus bar main body on the welding of the bus bar main body can be reduced by the length of the extension of the bus bar extension part. The good welding of the grid line of the solar cell, the solder tape and the extension part can be achieved by controlling the overlapping area of the bus bar extension part and the solder tape, and problems such as de-welding caused by high-temperature welding can be avoided. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 Schematic diagram of the arrangement of the battery cells of the photovoltaic module of the present application;

[0020] Figure 2 Schematic diagram of the structure of three adjacent battery cells of the photovoltaic module of the present application;

[0021] Figure 3 Schematic diagram of the structure of four adjacent battery cells of the photovoltaic module of the present application;

[0022] Figure 4 Schematic diagram of the structure of the photovoltaic module of the present application;

[0023] Figures 5 to 8 Schematic diagram of the bus bar of the present application;

[0024] Figure 9 Schematic diagram of the arrangement of the battery cells of the photovoltaic module of the present application;

[0025] Figure 10 Schematic diagram of the photovoltaic module of the prior art;

[0026] Figure 11 Partial schematic diagram of the photovoltaic module of the prior art.

[0027] The figure includes: 10 - battery string, 11 - battery cell, 21 - first solder tape, 22 - second solder tape, 30 - bus bar, 31 - edge bus bar, 32 - intermediate bus bar, 301 - bus bar main body, 302 - extension part, 300 - bus bar area, 40 - insulating layer. Detailed implementation manners

[0028] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will make a detailed description of the specific implementation manners of the present application in conjunction with the drawings.

[0029] In the following description, many specific details are set forth to fully understand the present application. However, the present application can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0030] Secondly, the present application will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present application in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally not in accordance with the general scale, and the schematic diagrams are only examples and should not limit the scope of protection of the present application herein. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0031] In the prior art, multiple back-contact solar cells form a photovoltaic cell module through steps such as series soldering or module-wide soldering, lamination, and encapsulation of the module. Among them, the photovoltaic cell module includes multiple cell strings, and two cell strings are connected in parallel through a bus bar. The bus bar in the prior art is arranged in the gap area between the cell string groups or in the gap area on one side of the cell string groups. Due to the existence of the gap area, the bus bar can also be seen from the front of the photovoltaic module, which affects the aesthetics; moreover, the existence of the gap area also occupies the space of the photovoltaic module and squeezes the area of the solar cells.

[0032] The embodiment of the present application provides a back-contact battery photovoltaic module, which reduces or eliminates the gap area between the cell strings, arranges the bus bar above a row of cells in the cell string group, hides the bus bar from the front of the photovoltaic module, improves the aesthetics of the module, and can effectively utilize the position of the photovoltaic module.

[0033] Based on this, please refer to Figures 1 to 3 , where Figure 1 is a schematic diagram of the structure of the photovoltaic module, where Figure 1 shows the cell strings and the area where the bus bar is placed, and the solder ribbons are not shown. Figure 2 shows three adjacent solar cells and the solder ribbons thereon in two adjacent cell strings. The middle solar cell shows all the solder ribbons, and only the solder ribbons connected to the middle solar cell are shown on the two side solar cells. Figure 3 shows two adjacent ones among the two outermost columns of solar cells. Among them, all the solder ribbons on the left solar cell are shown, and only the solder ribbons connected to the left solar cell are shown on the right solar cell. The embodiment of the present application provides a photovoltaic module, including multiple cell strings 10. The cell strings 10 are in the X direction, and the X direction and the Y direction are perpendicular directions, as shown in Figure 1It shows a battery string 10 including six arranged in the Y direction and one arranged in the X direction. Among them, the battery string 10 includes a plurality of battery cells 11 arranged in series in the X direction. In this embodiment, the battery cell 11 is a back-contact solar cell. Those skilled in the art are aware of the series connection method of the battery string of the back-contact solar cell. Specifically, the battery cell 11 includes a first grid line 101 and a second grid line 102 of opposite sexes arranged alternately on the back thereof. The first grid line 101 is connected by a first welding ribbon 21, and the second grid line 102 is connected by a second welding ribbon 22. The grid line can be set on the back of the battery cell 11 by screen printing, and the grid line is welded by the welding ribbon to electrically connect the battery cells, which plays a role in guiding current. In a battery string, two adjacent battery cells 11 are connected by a first welding ribbon 21, or by a second welding ribbon 22, which can be set according to the layout of the photovoltaic module. See Figure 2 and Figure 3 , Figure 2 The figure shows three adjacent cells in the middle of a string of cells. For clarity, the middle cell includes the solder ribbons connected to the cells on the left and right. The cells on both sides only show the solder ribbons connected to the middle cell. A middle cell 11 is adjacent to two cells 11. It is connected to the cell 11 on one side (left side in the figure) with a first solder ribbon 21 and to the cell 11 on the other side (right side in the figure) with a second solder ribbon 22. Figure 3 The figure shows two adjacent cells in the two leftmost columns. For clarity, the cell on the left shows all the soldering ribbons, while the cell on the right shows only the soldering ribbon connecting it to the cell on the left. All cells in a complete cell string are connected together by a first soldering ribbon and a second soldering ribbon. Multiple cell strings can be arranged together as a single cell string, or after all the cell strings and soldering ribbons are arranged, all the cell strings are welded together as a whole, for example, by laser welding, electromagnetic welding, or infrared welding.

[0034] The busbars 30 may include three groups, one of which is provided in two adjacent battery strings in the Y direction, on at least one of the adjacent battery cells 11, or on two adjacent battery cells 11; and one of which is provided on at least one battery cell 11 at both ends in the X direction, or on two adjacent battery cells 11. In the figure, the busbars 30 extend along the Y direction. Figure 1 An area 300 is shown where busbars are provided.

[0035] The busbar 30 is electrically connected to the first welding ribbon 21 and insulated from the second welding ribbon 22, or connected to the second welding ribbon 22 and insulated from the first welding ribbon 21. For the convenience of description, the welding ribbon that electrically connects the busbar to the battery is called a welding ribbon.

[0036] Continue to refer to Figure 2 and Figure 3 The bus bar 30 is arranged above the solar cell 11. The bus bar 30 includes a bus bar main body 301 and a plurality of extension parts 302 arranged at intervals along the extension direction of the bus bar main body 301. The extension parts 302 are perpendicular to the extension direction of the bus bar main body 301, and both ends of the extension parts 302 extend out of the bus bar main body 301. An insulating layer 40 is arranged below the bus bar 30. The insulating layer 40 extends along the extension direction of the bus bar main body 301. The width of the insulating layer 40 is greater than the width of the bus bar main body 301, and it does not exceed the extension parts 302 in the width direction. The length of the insulating layer 40 is not less than the length of the bus bar main body 301. In this way, the insulating layer isolates the bus bar main body from the solar cell and the first solder strip and the second solder strip. However, the extension parts of the bus bar extend out of the insulating layer and are located above the corresponding welding solder strips, where they are welded to the corresponding solder strips.

[0037] Those skilled in the art can understand that the first grid line 101 can be a positive grid line, and the corresponding second grid line 102 is a negative grid line; conversely, the first grid line 101 can also be a negative grid line, and the corresponding second grid line 102 is a positive grid line.

[0038] In the prior art's photovoltaic module with a hidden bus bar, the setting of the insulating glue inevitably blocks some fine grid lines, affecting the current collection effect. In the photovoltaic module of the present application, both the first solder strip and the second solder strip are connected to all the corresponding grid lines of the solar cell. The current is introduced into the bus bar through the solder strip by the extension part, making full use of each grid line of the solar cell, better collecting the current, and improving the current collection effect. Refer to Figure 11 which is a partial structural schematic diagram of a prior art photovoltaic module with a hidden bus bar. The insulating layer is arranged below the bus bar. In order to ensure the connection between the bus bar and the first solder strip and the insulation from the second solder strip, a way of hollowing out the insulating layer at the position corresponding to the first solder strip is adopted. This easily leads to problems such as a height difference between the bus bar and the solder strip, a small contact area between the solder strip and the bus bar, and poor welding. Adopting the technical solution of the present application well solves this problem. The extension part extends outwards, and the adverse effects brought by the height difference of the insulating layer can be eliminated through its extension length, and good welding between the solder strip and the extension part can be achieved by controlling the overlapping area between the solder strip and the extension part.

[0039] More importantly, the bus bar includes a main body and an extension part extending outward. The design is such that only the extension part corresponding to the welding tape is welded to the welding tape of the cell grid line. Compared with the method of welding the bus bar main body to the cell grid line, the required welding energy is low, which can effectively avoid the technical problem of the welding tape and the cell grid line becoming desoldered due to the high welding energy of the bus bar main body. At the same time, the height difference caused by the insulating layer under the bus bar main body can be alleviated by the length of the extension part of the bus bar, which has an adverse effect on the welding of the bus bar main body. By controlling the overlapping area of the extension part of the bus bar and the welding tape, good welding can be achieved between the cell grid line, the welding tape and the extension part, thus avoiding problems such as desoldering caused by high-temperature welding.

[0040] As a half-cell BC type battery, the bus bars 31 on both sides of the component include multiple ones. Among them, the bus bars 31 on both sides connect the same-sex welding tapes of one cell 11, or connect the opposite-sex welding tapes of two adjacent cells 11, and are disconnected in the middle. The middle bus bar 32 of the component includes multiple ones. The middle bus bar 32 connects the same-sex welding tapes of one cell 11, or connects the opposite-sex welding tapes of two adjacent cells 11, and is disconnected in the middle. The disconnected position of the middle bus bar 32 is staggered from the disconnected position of the bus bars 31 on both sides. Figure 1 For example, there are three bus bars 31 on both sides, and each connects the welding tapes on two adjacent cells 11; there are four middle bus bars 32, which connect the welding tapes on the upper one, the middle two, the middle two again, and the lower one cell 11 respectively. Among them, when the number of columns of the cells 11 is the same, the polarities of the welding tapes connected by the bus bars on both sides are the same, and are different from the polarities of the welding tapes connected by the middle bus bar. If the component circuit is not a symmetrically arranged half-cell configuration, the corresponding way of connecting the welding tapes to the cells changes according to the design of the component circuit.

[0041] As an optional implementation manner, referring to the schematic Figure 4 , taking six columns of cells as an example, from top to bottom are the first column to the sixth column. The bus bars on both sides connect the second welding tapes, the first welding tapes, the second welding tapes, the first welding tapes, the second welding tapes, and the first welding tapes on the cells from the first column to the sixth column respectively; and are disconnected between the second column and the third column, and between the fourth column and the fifth column. The middle bus bars connect the first welding tapes, the second welding tapes, the first welding tapes, the second welding tapes, the first welding tapes, and the second welding tapes on the cells from the first column to the sixth column respectively; and are disconnected between the first column and the second column, between the third column and the fourth column, and between the fifth column and the sixth column.

[0042] Correspondingly, the insulating layer 40 can be arranged in one-to-one correspondence with the bus bar 30. Specifically, it is arranged under the bus bar 30. In the orthographic projection direction of the bus bar 30, only the extension part 302 (generally part of the extension part) is outside the insulating layer 40 and is connected to the first welding tape 21 on the cell 11, or is connected to the second welding tape 22 on the cell. When welding the bus bar 30, the welding tape connected to the extension part 302 is welded.

[0043] The bus bar 30 can be integrally formed. Refer to Figure 5 , which is a schematic structural diagram of the integrally formed bus bar. At this time, the bus bar main body 301 and the extension part 302 are integrated.

[0044] The bus bar main body 301 and the extension part 302 of the bus bar 30 can also be separately formed and then assembled together. Specifically, prepare a strip-shaped bus bar main body 301 and a comb-shaped extension part 302; place multiple extension parts 302 extending along the width direction of the bus bar main body 301 at intervals along the extension direction of the bus bar main body 301, and weld the extension part 302 and the bus bar main body 301 to form the required bus bar 30. Refer to Figure 6 and Figure 7 , which are respectively schematic structural diagrams for preparing the bus bar, where Figure 7 uses dots to schematically show the welding points between the bus bar main body and the extension part.

[0045] Compared with integral forming, using a conventional bus bar and a solder tape to prepare a bus bar with a welding part can prepare different bus bars according to different patterns, and the method is more flexible.

[0046] Preferably, the width of the bus bar main body 301 is 3 - 20 mm. The length that the extension part 302 extends out of the bus bar main body 301 is 1 - 60 mm, and the width of the extension part is 0.1 - 4 mm.

[0047] The extension part can be located above the bus bar main body (away from the battery cell), or can be located below the bus bar main body (close to the battery cell). The extension part can also be integrally stamped and formed with the bus bar main body.

[0048] The insulating layer can be directly fixed on the bus bar. Refer to Figure 8 , which is a schematic structural diagram of the insulating layer fixed on the bus bar. The insulating layer is a non-conductive tape or insulating film. For example, it can be a PET or PI tape with acrylic or silicone, or a PET or PI substrate with ethylene-vinyl acetate copolymer or hot melt adhesive laminated on one or both sides. For example, the insulating layer can be fixed on the bus bar by heating. The insulating layer can also be formed by coating, such as spraying, and then curing.

[0049] Please refer to Figure 9, in the embodiments of the present application, in a row of solar cells, the spacing between adjacent solar cells 11 is very small, preferably 0 spacing, or they are stacked with negative spacing. The adjacent solar cells are stacked with negative spacing. When adjacent solar cells in a row are stacked with negative spacing, for a solar cell, one side is located below the adjacent solar cell, and the other side is located above another adjacent solar cell. Among them, the size of the stacked adjacent solar cells is 0.2 - 0.5 mm.

[0050] By using the method of the present invention, the solar cells can be placed with negative spacing, further improving the utilization rate of the space of the photovoltaic module and increasing the power of the module.

[0051] As a preferred embodiment, between adjacent rows of solar cells, an insulating material is filled in the gap. When there is a gap between adjacent solar cells in a row, the insulating material is also filled in the gap. At least part of the insulating material overflows to the upper surface of the adjacent solar cells. Specifically, the insulating material here can be a hot-pressing material, which can be extruded and flow during the lamination of the photovoltaic module. The gaps between adjacent solar cells or between each solar cell of adjacent columns of solar cells and the adjacent solar cells are all filled with the material, releasing the stress between the adjacent solar cells and avoiding the warping of the solar cells.

[0052] By using the method of the present invention, the stress between adjacent solar cells after lamination can be released by filling the insulating material, avoiding the warping of the solar cells.

[0053] The above structure of the present application is more applicable to solar cells without main grids. It can be understood that the solar cells without main grids refer to those in which fine grids are provided on the solar cells 11 and no main grid is provided, and the fine grids of the same polarity are electrically connected through solder tapes to directly conduct the current on the fine grids.

[0054] The above are only the preferred embodiments of the present application. Although the present application has been disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present application, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the protection of the technical solution of the present application.

Claims

1. A photovoltaic module with a hidden busbar, characterized in that: Comprising a plurality of battery strings, each of the plurality of battery strings includes a plurality of solar cells connected in series along the X direction, and the plurality of battery strings are arranged along the Y direction on the photovoltaic module. The solar cells include first grid lines and second grid lines of opposite genders alternately arranged on the back surface. The first grid lines are connected by first solder tapes, and the second grid lines are connected by second solder tapes. In a string of battery strings, adjacent two solar cells are connected by a first solder tape or a second solder tape. It further includes busbars, and the busbars are arranged on at least one of the adjacent solar cells of two adjacent battery strings in the Y direction, and / or the busbars are arranged on at least one of the adjacent solar cells at both ends in the X direction of two adjacent battery strings in the Y direction. The busbar includes a busbar main body and a plurality of extension parts arranged at intervals along the extension direction of the busbar main body. The extension direction of the extension part is perpendicular to the extension direction of the busbar main body, and both ends of the extension part extend out of the busbar main body. It further includes an insulating layer arranged between the busbar and the solar cell. The insulating layer extends along the extension direction of the busbar main body. The width of the insulating layer is not less than the width of the busbar main body, and it does not exceed the extension part in the width direction. The insulating layer isolates the busbar main body from the solar cell, the first solder tape, and the second solder tape. The extension part extends out of the insulating layer and is welded to the corresponding solder tape for electrical connection.

2. The photovoltaic module with a hidden busbar according to claim 1, wherein: The extension part and the busbar are integrally formed, or the extension part is arranged on the upper or lower part of the busbar main body.

3. A photovoltaic module with a hidden bus bar according to claim 1, characterized in that: The extension part is welded to the busbar main body.

4. A photovoltaic module with a hidden busbar according to claim 2, characterized in that: The width of the busbar main body is 3 to 20 mm.

5. A photovoltaic module with a hidden busbar according to claim 1, characterized in that: The length of the extension part extending out of the insulating layer is 1 to 60 mm, and the width of the extension part is 0.1 to 4 mm.

6. The photovoltaic module with a hidden bus bar according to claim 1, wherein: The length of the insulating layer is greater than the length of the busbar main body.

7. A photovoltaic module with a hidden busbar according to claim 5, characterized in that: The width of the extension part is 0.5 to 4 times the width of the solder tape for electrical connection.

8. The photovoltaic module with a hidden busbar according to claim 1, wherein: In a string of battery strings, the distance between adjacent solar cells is zero distance or negative distance stacking.

9. A photovoltaic module with a hidden busbar according to claim 1, characterized in that: When adjacent solar cells are stacked with negative distance, for one solar cell, one side is located below the adjacent solar cell, and the other side is located above the other adjacent solar cell. The stacking size of adjacent solar cells is 0.2 to 0.5 mm.

10. A photovoltaic module with a hidden bus bar according to claim 1, characterized in that: The solar cell is a main-gridless back-contact solar cell.

11. A photovoltaic module with a hidden busbar according to claim 1, characterized in that: The busbar main body extends along the Y direction.

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