Battery string and full-screen photovoltaic module

Abstract

The invention provides a battery string and a full-screen photovoltaic module. The battery string is formed by splicing a first battery short string and a second battery short string, welding strips are fixed on the surfaces of the first battery short string and the second battery short string, and each welding strip comprises a connecting electrode and a non-connecting electrode; a bus bar is arranged at the splicing position of the first battery short string and the second battery short string, the bus bar comprises a main body part and a welding strip lap joint part which protrudes out of the main body part and is used for being connected with the electrodes in a lap joint mode, and the first battery short string and the second battery short string on the two sides of the bus bar are symmetrical relative to the bus bar; the distance from the tail end of the non-connection electrode to the main body part is larger than 0, and the distance from the tail end of the connection electrode to the welding strip lap joint part is smaller than 0.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaics, in particular to a cell string and a full-screen photovoltaic module. BACKGROUND

[0002] The front side of a back contact (BC) solar cell is completely free of grid lines, so it has higher cell efficiency, and the appearance of a full-screen photovoltaic module formed by back contact cells is also more beautiful. With the continuous development of back contact cell and photovoltaic module technology, in order to improve the efficiency of the full-screen photovoltaic module, many new connection methods and design schemes of back contact cells have emerged, among which the use of the lamination process and the hidden busbar method can accommodate more photovoltaic cells in a limited module area, thereby improving the module efficiency.

[0003] The existing hidden design of the busbar is achieved by placing the busbar on the solder strip on the back of the cell. However, for a full-screen photovoltaic module formed by back contact cells, an isolation strip needs to be provided between the soldering of the busbar and the non-connected electrode of the solder strip to achieve the insulation of the busbar and the non-connected electrode. This further increases the height of the busbar to the surface of the cell. The large height of the busbar to the surface of the cell not only increases the risk of lamination breakage of the module, but also increases the amount of adhesive film used in the module. In addition, when the module is connected by an even number of cell strings, the placement of the busbar in the middle of the cell will cause a current mismatch risk.

[0004] In order to overcome the above-mentioned defects existing in the prior art, there is an urgent need in the art for a cell string and a full-screen photovoltaic module that can reduce the distance from the top of the busbar to the surface of the cell, thereby reducing the risk of lamination breakage of the module and achieving cost reduction and efficiency improvement of the module. SUMMARY

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] In order to overcome the above-mentioned defects existing in the prior art, the present application provides a cell string and a full-screen photovoltaic module that can reduce the distance from the top of the busbar to the surface of the cell, thereby reducing the risk of lamination breakage of the module and achieving cost reduction and efficiency improvement of the module.

[0007] Specifically, according to the battery string provided by the application, the battery string is formed by splicing a first battery short string and a second battery short string, the surface of the first battery short string and the second battery short string is fixed with a welding strip, the welding strip includes a connecting electrode and a non-connecting electrode, and the splicing part of the first battery short string and the second battery short string is provided with a busbar, the busbar includes a main body part and a welding strip lapping part protruding from both sides of the main body part for lapping the connecting electrode, the first battery short string and the second battery short string on both sides of the busbar are symmetrical relative to the busbar, the distance from the end of the non-connecting electrode to the main body part is greater than 0, and the distance from the end of the connecting electrode to the welding strip lapping part is less than 0.

[0008] Preferably, in an embodiment of the application, the height between the main body part of the busbar and the battery string is greater than the height between the welding strip lapping part and the battery string.

[0009] Preferably, in an embodiment of the application, the width of the welding strip lapping part is greater than the width of the connecting electrode.

[0010] Preferably, in an embodiment of the application, the welding strip lapping part is a metal film or a metal sheet or a composite material formed by a metal substrate and a conductive coating.

[0011] Preferably, in an embodiment of the application, the cross-sectional shape of the welding strip lapping part includes a rectangle, a circle or a triangle.

[0012] Preferably, in an embodiment of the application, the busbar is an integral structure or a composite structure formed by a first conductive layer and a second conductive layer.

[0013] Preferably, in an embodiment of the application, the position where the welding strip lapping part overlaps and contacts the connecting electrode is provided with a protrusion.

[0014] Preferably, in an embodiment of the application, the first battery short string and the second battery short string each include at least two battery pieces.

[0015] In addition, the second aspect of the application provides the above-mentioned full-screen photovoltaic module, which includes at least one battery string provided by any one of the above-mentioned embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above features and advantages of the application can be better understood after reading the detailed description of embodiments of the application in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components having similar related properties or features can have the same or similar reference numerals.

[0017] Figure 1A schematic diagram showing the busbar connection of an existing back contact cell is shown;

[0018] Figure 2 A schematic diagram showing the busbar connection of an existing full screen PV module 200 is shown;

[0019] Figure 3 A schematic diagram showing the side of the busbar connection of an existing full screen PV module 200 is shown;

[0020] Figure 4 A schematic diagram showing a full screen PV module 400 provided according to some embodiments of the present application is shown;

[0021] Figure 5 A schematic diagram showing the side of the busbar connection of a full screen PV module 400 provided according to some embodiments of the present application is shown;

[0022] Figure 6 A cross-sectional view of a busbar provided according to some embodiments of the present application is shown;

[0023] Figure 7 A cross-sectional view of a busbar provided according to some embodiments of the present application is shown;

[0024] Figure 8 A schematic diagram showing the busbar connection provided according to some embodiments of the present application is shown;

[0025] Figure 9 A cross-sectional view of a busbar provided according to some embodiments of the present application is shown; and

[0026] Figure 10 A cross-sectional view of a busbar provided according to some embodiments of the present application is shown.

[0027] Reference signs:

[0028] 101: fixing glue;

[0029] 102: solder tape;

[0030] 103: cell;

[0031] 104: busbar;

[0032] 200: full screen PV module;

[0033] 201: fixing glue;

[0034] 210: busbar;

[0035] 220: cell;

[0036] 230: solder tape;

[0037] 231: connection electrode;

[0038] 232: insulated electrode;

[0039] 240: insulation strip;

[0040] 400: full-screen photovoltaic module;

[0041] 401: fixing adhesive;

[0042] 410: cell string;

[0043] 411: first cell short string;

[0044] 412: second cell short string;

[0045] 420: solder strip;

[0046] 421: non-connection electrode;

[0047] 422: connection electrode;

[0048] 430: busbar;

[0049] 431: main body portion;

[0050] 432: solder strip lap portion;

[0051] 501: soldered portion;

[0052] 600: busbar;

[0053] 610: main body portion;

[0054] 620: solder strip lap portion;

[0055] 700: busbar;

[0056] 710: first conductive layer;

[0057] 720: second conductive layer;

[0058] 801: connection electrode;

[0059] 802: non-connection electrode;

[0060] 810: busbar;

[0061] 900: busbar;

[0062] 1000: busbar;

[0063] 1010: first conductive layer;

[0064] 1020: second conductive layer;

[0065] 1021: solder strap overlap; and

[0066] 1022: protrusion. DETAILED DESCRIPTION

[0067] The present application is described in detail below with reference to the attached drawing figures and specific embodiments. It should be noted that the aspects described below with reference to the drawing figures and specific embodiments are merely exemplary and should not be construed to limit the scope of the present application.

[0068] In the description of the present application, it is necessary to note that the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0069] In addition, "upper", "lower", "left", "right", "top", "bottom", "horizontal", "vertical" used in the following description should be understood as the orientation shown in the section and the related drawings. The relative terms are only for the convenience of description, and do not mean that the device described should be manufactured or operated in a particular orientation, so it should not be understood as a limitation on the present application.

[0070] It can be understood that although the terms "first", "second", "third" and the like can be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below can be referred to as the second component, region, layer and / or part without departing from some embodiments of the present application.

[0071] As described above, the hidden design of the existing busbar is achieved by placing the busbar on the solder strap on the back of the battery. However, for a full-screen photovoltaic module formed by back-contact batteries, an isolation strip needs to be provided between the busbar and the soldering of the non-connecting electrode of the solder strap to achieve the insulation of the busbar and the non-connecting electrode. This further increases the height of the busbar to the surface of the battery sheet. The large height of the busbar to the surface of the battery sheet not only increases the risk of lamination breakage of the module, but also increases the amount of adhesive film of the module. In addition, when the module is connected by an even number of battery strings, the placement of the busbar in the middle of the battery sheet will have the risk of current mismatch.

[0072] Please refer to Figure 1 , Figure 1A schematic diagram of the busbar connection of the existing back contact cell is shown.

[0073] As shown in Figure 1 , in a conventional back contact cell without main grid, the solder ribbon 102 is fixed on the cell piece 103 by the fixing glue 101. The cell piece 103 is the cell piece at the end of the left and right two cell strings, and a busbar 104 can be connected between the cell pieces 103 at the ends of the two cell strings. The end of the solder ribbon 102 close to the end of the cell string is connected with the busbar 104. There is no overlapping part between the busbar 104 and the cell piece 103 at the end of the cell string. The distance between the upper surface of the busbar 104 and the lower surface of the cell piece 103 is H1. However, in the existing full-screen photovoltaic module, in order to realize the hidden design of the busbar, the busbar is overlapped with the cell piece and placed at the middle position of the cell piece.

[0074] Please refer to Figure 2 and Figure 3 , Figure 2 A schematic diagram of the busbar connection of the existing full-screen photovoltaic module 200 is shown, Figure 3 A schematic diagram of the side of the busbar connection of the existing full-screen photovoltaic module 200 is shown.

[0075] As shown in Figure 2 , the full-screen photovoltaic module 200 can be composed of a plurality of cell pieces 220. The busbar 210 is placed at the middle position of the cell piece 220. A plurality of solder ribbons 230 are fixed on the back of the cell piece 220, and the solder ribbon 230 includes a connecting electrode 231 and an insulating electrode 232. The busbar 210 is in contact with the connecting electrode 231 and is insulated from the insulating electrode 232. Specifically, the busbar 210 and the insulating electrode 232 are insulated by adding an insulating strip on the insulating electrode 232. Therefore, the busbar 210 is actually arranged above the insulating electrode 232 and the insulating strip (not shown) of the solder ribbon 230.

[0076] As shown in Figure 3 , the solder ribbon 230 is fixed on the cell piece 220 by the fixing glue 201. Since the busbar 210 needs to be insulated from the insulating electrode 232, an insulating strip 240 can be further arranged between the busbar 210 and the insulating electrode 232. In this way, the distance between the upper surface of the busbar 210 and the lower surface of the cell piece 220 is H2. The distance H2 includes the height of the busbar 210, the insulating strip 240, the solder ribbon 230, and the cell piece 220, which is greater than the distance H1 in the conventional scheme without hiding the busbar as shown in Figure 1 . During the lamination process, the increase of the distance between the busbar and the cell piece will bring higher risk of broken pieces during lamination; at the same time, in order to ensure the reliability of the module, the increase of the distance between the busbar and the cell piece will increase the thickness of the glue film, which increases the cost and reduces the reliability of the module.

[0077] In order to overcome the above-mentioned defects of the prior art, the application provides a battery string and a full-screen photovoltaic module, which can reduce the distance from the top of the busbar to the surface of the battery, thereby reducing the risk of laminate chip of the module and achieving cost reduction and efficiency improvement of the module.

[0078] Please refer to Figure 4 , Figure 4 A schematic diagram of a full-screen photovoltaic module 400 provided according to some embodiments of the application is shown.

[0079] As Figure 4 shown, the full-screen photovoltaic module 400 can include at least one battery string 410, which is no longer composed of a whole string. The battery string 410 can be formed by splicing a first battery short string 411 and a second battery short string 412. The first battery short string 411 and the second battery short string 412 can each include at least two battery pieces. The surfaces of the first battery short string 411 and the second battery short string 412 can be respectively fixed with a solder strip 420. The solder strip 420 can include a non-connecting electrode 421 and a connecting electrode 422.

[0080] The splicing position of the first battery short string 411 and the second battery short string 412 is further provided with a busbar 430, and the first battery short string 411 and the second battery short string 412 on both sides of the busbar 430 can be symmetrical relative to the busbar 430. In this way, compared with the existing design of placing the busbar in the middle of the battery piece, the full-screen photovoltaic module 400 can greatly improve the risk brought by current mismatch.

[0081] The busbar 430 can include a protruding structure, that is, the busbar 430 can include a main body part 431 and a solder strip lap part 432 protruding on both sides of the main body part 431 in the transverse direction for lap joint with the connecting electrode 422. The distance from the end of the non-connecting electrode 421 to the main body part 431 of the busbar 430 is greater than 0, so that the non-connecting electrode and the busbar are not in contact, and therefore, an insulating layer is not needed to isolate the non-connecting electrode and the busbar. The distance from the end of the connecting electrode 422 to the edge of the solder strip lap part 432 of the busbar 430 is less than 0, that is, the end of the connecting electrode 422 overlaps the edge of the solder strip lap part 432 of the busbar 430, so as to ensure that the solder strip lap part 432 of the busbar 430 can be better lap joint on the connecting electrode 422.

[0082] Please refer to Figure 5 , Figure 5 A schematic diagram of the side of the busbar connection of the full-screen photovoltaic module 400 provided according to some embodiments of the application is shown.

[0083] Please refer to Figure 4 and Figure 5In some embodiments, the solder ribbon 420 can be fixed to the battery cell using adhesive 401. The main body 431 of the busbar 430 can be centrally positioned at the junction of the first battery string 411 and the second battery string 412 of the battery string 410. The solder ribbon overlap 432 can be welded to the connecting electrodes 422 of the first battery string 411 and the second battery string 412 on both sides, and the overlapping part formed by the welding is the welded part 501. When adhesive is applied to the end of the solder ribbon 420, it will not affect the curing of the adhesive 401.

[0084] Preferably, in some embodiments, the height between the main body of the busbar and the battery string 410 can be greater than the height between the solder strip overlap and the battery string 410.

[0085] like Figure 5 As shown, the height between the main body 431 of the busbar 430 and the battery string 410 can be H3, and the height of the welded part 501 formed by welding the solder strip overlap 432 and the connecting electrode 422 from the battery string 410 can be H4. The height H3 can be greater than the height H4.

[0086] In some embodiments, the main body and the weld strip overlap of the busbar can be a one-piece structure formed in one step. In other embodiments, the main body and the weld strip overlap of the busbar can be a composite structure formed by a first conductive layer and a second conductive layer.

[0087] Please refer to Figure 6 and Figure 7 , Figure 6 and Figure 7 A cross-sectional view of a busbar provided according to some embodiments of the present invention is shown.

[0088] exist Figure 6 In the embodiment shown, the main body 610 and the weld strip overlap 620 of the busbar 600 can be a one-piece structure formed in one step.

[0089] like Figure 7 As shown, the busbar 700 can also be a composite structure formed by a first conductive layer 710 and a second conductive layer 720. The length of the second conductive layer 720 can be greater than the length of the first conductive layer 710, thereby forming a protruding structure in the lateral direction to constitute the main body and the solder strip overlap of the busbar 700. Preferably, the thickness of the first conductive layer 710 can be greater than the thickness of the second conductive layer 720.

[0090] In some embodiments, the second conductive layer 720 may be made of a flexible metal material so that it can be bent upwards and overlapped on the connecting electrodes of the battery short string.

[0091] In some embodiments, the width of the solder strip overlap portion can be greater than the width of the solder strip. The solder strip overlap portion can be a single metallic film or sheet material, or a composite material formed from a metallic substrate and a conductive coating. Since the width of the solder strip overlap portion can be greater than the width of the solder strip, the thickness of the solder strip overlap portion can be thin, thereby reducing the overall height of the busbar to the surface of the battery string.

[0092] Please refer to Figure 8 and Figure 9 , Figure 8 A schematic diagram of a busbar connection is shown, according to some embodiments of the present application, Figure 9 A cross-sectional view of a busbar is shown, according to some embodiments of the present application.

[0093] As Figure 8 shown, the solder strip overlap portion of the busbar 810 can not be limited to a rectangular shape, but can also be a triangular shape. The connection electrode 801 of the battery string can form a solder portion with the solder strip overlap portion of the busbar, and the non-connection electrode 802 does not contact the busbar 800.

[0094] In other embodiments, the solder strip overlap portion of the busbar can also be any arbitrary shape protruding from the main body portion, such as a circular shape.

[0095] Furthermore, the cross-section of the solder strip overlap portion of the busbar can also not be rectangular, as Figure 9 shown, the cross-section of the solder strip overlap portion of the busbar 900 can be a beveled shape.

[0096] In some embodiments, the solder strip overlap portion can overlap and contact the connection electrode, and the position where the solder strip overlap portion overlaps and contacts the connection electrode can be provided with regular or irregular protrusions.

[0097] Please refer to Figure 10 , Figure 10 A cross-sectional view of a busbar is shown, according to some embodiments of the present application.

[0098] As Figure 10 shown, the busbar 1000 can be a composite structure formed from a first conductive layer 1010 and a second conductive layer 1020. The second conductive layer 1020 protrudes from a portion of the first conductive layer 1010 to form a solder strip overlap portion 1021. The portion of the solder strip overlap portion 1021 that overlaps and contacts the connection electrode for soldering can be provided with regular or irregular protrusions 1022. Through the protrusions 1022, the solder strip overlap portion 1021 of the busbar 1000 can improve the possibility of poor soldering between the connection electrode and the busbar 1000 due to shaking during soldering.

[0099] In conclusion, the battery string provided by the application adopts the design of bus bar with hierarchical thickness, the bus bar can be directly contacted with the battery piece, the influence of the height of the insulation layer is eliminated, and the risk of laminated broken pieces can be greatly reduced. Meanwhile, due to the reduction of the overall height of the full-screen photovoltaic module composed of the battery string, the use amount of the adhesive film can be reduced, and the cost can be reduced.

[0100] The foregoing description of the present disclosure has been provided for the purposes of illustrating and describing but not limiting the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the examples described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery string, characterized in that, The battery string is formed by splicing together a first battery short string and a second battery short string. The surfaces of the first and second battery short strings are fixed with solder strips, which include connecting electrodes and non-connecting electrodes. A busbar is provided at the splice of the first battery string and the second battery string. The busbar includes a main body and solder strip overlap portions protruding from both sides of the main body for overlapping the connecting electrodes. The first battery string and the second battery string on both sides of the busbar are symmetrical with respect to the busbar. The distance from the end of the non-connecting electrode to the main body is greater than 0, and the distance from the end of the connecting electrode to the solder strip overlap portion is less than 0.

2. The battery string as described in claim 1, characterized in that, The height between the main body of the busbar and the battery string is greater than the height between the overlap of the welding strip and the battery string.

3. The battery string as described in claim 1, characterized in that, The width of the overlap of the welding strip is greater than the width of the connecting electrode.

4. The battery string as described in claim 1, characterized in that, The weld strip overlap is a composite material formed by a metal film, a metal sheet, a metal substrate, and a conductive coating.

5. The battery string as described in claim 1, characterized in that, The cross-sectional shape of the weld strip overlap includes rectangle, circle or triangle.

6. The battery string as described in claim 1, characterized in that, The busbar is either an integral structure or a composite structure formed by a first conductive layer and a second conductive layer.

7. The battery string as described in claim 1, characterized in that, The position where the welding strip overlaps and contacts the connecting electrode is provided with a protrusion.

8. The battery string as described in claim 1, characterized in that, The first battery short string and the second battery short string each include at least two battery cells.

9. A full-screen photovoltaic module, characterized in that, It includes at least one battery string as described in any one of claims 1 to 8.

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