Back contact battery assembly and photovoltaic system

Abstract

The utility model is suitable for the field of photovoltaic technology, and provides a back contact battery assembly and a photovoltaic system, and the back contact battery assembly comprises a plurality of battery pieces; the plurality of welding strips are connected with two adjacent battery pieces; the insulating film is located on the side, away from the battery piece, of the welding strip, a plurality of exposed areas are formed on the insulating film, and the welding strip with the same polarity is exposed out of the exposed areas; the bus bar is arranged on the side, away from the battery piece, of the insulating film, the bus bar comprises a plurality of protruding structures and a plurality of connecting parts connected between the protruding structures, and the protruding structures extend into the corresponding exposed areas to be in conductive connection with the exposed welding strips. According to the invention, the current collection effect can be effectively improved while the bus bar is hidden, and in addition, due to the special design of the bus bar and the stable connection of the bus bar and the welding strip, the filling of a gap in an exposed region is facilitated, and the reliability of the battery assembly is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photovoltaic, and particularly relates to a back contact cell module and a photovoltaic system. BACKGROUND

[0002] A solar cell, also known as a photovoltaic cell, is a device for directly converting light energy into direct current electricity by using photovoltaic effect. A PN junction on a semiconductor in the solar cell can directly convert solar energy into electrical energy by photovoltaic effect. The most common one is a crystalline silicon solar cell, including a single crystal silicon solar cell and a polycrystalline silicon solar cell. The solar cell is usually in a sheet shape. The solar cell with electrodes of two polarities formed on the back surface is a back contact cell.

[0003] In the related art, a plurality of cell pieces are subjected to steps such as series welding, lamination and packaging to form a back contact cell module. The back contact cell module includes a busbar for connecting two cells in series. In order to hide the busbar, the busbar is arranged on the back surface of the cell in the related art. In order to prevent the cell piece from being short-circuited, an insulating layer is usually arranged on the cell piece to insulate the busbar from the cell piece as a whole. Although this method can prevent the busbar from short-circuiting the cell piece, the current collection effect is poor. CONTENT OF THE UTILITY MODEL

[0004] The application provides a solar cell, which aims to solve the problem that the current collection effect is poor when an insulating layer is arranged on a cell piece to insulate a busbar from the cell piece as a whole.

[0005] The application is implemented in the following manner. A back contact cell module includes a plurality of cell pieces, a plurality of solder strips connected to two adjacent cell pieces, an insulating film arranged on a side of the solder strip away from the cell piece, the insulating film being formed with a plurality of exposed areas, the plurality of exposed areas exposing the solder strips of the same polarity, and a busbar arranged on a side of the insulating film away from the cell piece, the busbar including a plurality of protruding structures and a plurality of connecting portions connected between the plurality of protruding structures, the plurality of protruding structures being respectively inserted into the corresponding exposed areas and electrically connected to the exposed solder strips.

[0006] Optionally, a top surface of the protruding structure is a planar structure, and the protruding structure and the solder strip are in surface-to-surface contact.

[0007] Optionally, the insulating film has a thickness of 300-600 microns.

[0008] Optionally, the protruding structure has a height of 300-800 microns.

[0009] Optionally, the insulating film is provided with a through hole forming the exposed area.

[0010] Optionally, the outer peripheral wall of the protruding structure and the inner peripheral wall of the through hole are in contact with each other.

[0011] Optionally, the protruding structure comprises at least one of an arc shape, a rectangular shape, or a trapezoidal shape.

[0012] Optionally, the width of the insulating film is greater than or equal to the width of the bus bar.

[0013] Optionally, a plurality of the solder strips extend in a first direction to connect a plurality of the battery pieces to form a battery string, the bus bar extends in a second direction to connect a plurality of the battery strings, the insulating film and the bus bar extend in the same direction, and the insulating film and the bus bar are located at the middle part of the battery piece at the end of the battery string.

[0014] Optionally, two adjacent battery pieces are partially overlapped.

[0015] The application provides an insulating film on the side of the solder strip away from the battery piece, and an exposed area of the insulating film exposes the solder strip of the same polarity, the bus bar comprises a protruding structure, and the protruding structure extends into the corresponding exposed area, so that when the bus bar is arranged on the side of the insulating film away from the battery piece, the bus bar can be conductively connected with the solder strip exposed in the corresponding exposed area of the insulating film, and the bus bar is insulated from the solder strip not exposed, thereby preventing the short circuit of the battery piece, and the structure can make the solder strip completely adhere to the battery piece, so that even if the insulating film is arranged, the solder strip can be connected with enough fine grids, the current can be fully collected, and the current collection effect is improved. It can be understood that the structure of the back contact battery assembly can hide the bus bar and effectively improve the current collection effect. In addition, due to the special design of the bus bar, the bus bar and the solder strip are stably connected, the gap in the exposed area is filled, and the reliability of the battery assembly is improved.

[0016] A photovoltaic system comprises the back contact battery assembly, and the photovoltaic system has the same technical effects as the back contact battery assembly, and details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a partial structure schematic view of a first back contact battery assembly provided in the application;

[0018] Figure 2 is a partial structure schematic view of a second back contact battery assembly provided in the application;

[0019] Figure 3Fig. 3 is a schematic view of a partial structure of a third back contact battery assembly provided in the present application.

[0020] Explanation of reference signs:

[0021] 100, battery piece; 200, solder strip; 300, insulation film; 301, exposed area; 302, through hole; 400, bus bar; 401, protruding structure; 402, connecting part. DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and cannot be used to limit the present application.

[0023] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0024] In addition, the terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0025] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between 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.

[0026] In this application, unless otherwise explicitly specified and limited, "on", "under" and "above" or "lower" and "upper" of a first feature from a second feature can include that the first and second features are directly in contact, or that the first and second features are not directly in contact but are in contact through another feature between them. Also, "on", "over" and "above" of a first feature from a second feature include that the first feature is directly above and obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. "Under", "below" and "underneath" of a first feature from a second feature include that the first feature is directly below and obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0027] The disclosure hereafter provides many different embodiments or examples for implementing different structures of the application. For the purpose of simplification of the present disclosure, certain examples of the components and arrangements are described hereafter. These are, of course, merely examples and are in no way intended to limit the application. Moreover, the application can be implemented in different examples with different components and / or arrangements. The repeated use of reference characters in the present description denotes reference to the present structures and elements throughout the different illustrative examples mentioned herein. In other words, when several examples of a particular structure are described as being used in a particular example, it is intended that each of these structures can be used individually or together with any other structures described in this example. Furthermore, the present application provides examples of various specific processes and materials, but one skilled in the art will recognize that other processes and / or materials can be used.

[0028] As Figure 1 and Figure 2As shown, a back contact battery assembly includes a plurality of battery pieces 100, a plurality of solder strips 200, an insulating film 300 and a bus bar 400. The solder strips 200 connect two adjacent battery pieces 100, the insulating film 300 is located on the side of the solder strips 200 away from the battery pieces 100, the insulating film 300 is formed with a plurality of exposed areas 301, the plurality of exposed areas 301 expose the solder strips 200 of the same polarity, the bus bar 400 is arranged on the side of the insulating film 300 away from the battery pieces 100, the bus bar 400 includes a plurality of protruding structures 401 and a plurality of connecting portions 402 connected between the plurality of protruding structures 401, the plurality of protruding structures 401 respectively extend into the corresponding exposed areas 301 and are electrically connected with the exposed solder strips 200, and the insulating film 300 insulates the bus bar 400 from the non-exposed solder strips 200. In the embodiment of the application, the battery string includes a plurality of battery pieces 100, and the plurality of battery pieces 100 are connected in series by the solder strips 200. The number of solder strips 200 is a plurality, and the plurality of solder strips 200 include solder strips 200 of two polarities, and the solder strips 200 of the two polarities are respectively connected with electrodes of two different polarities. It can be understood that the battery piece 100 can be made of a semiconductor material, such as a P-type silicon wafer, which forms a P-N junction after phosphorus diffusion. Among them, the semiconductor structure absorbs solar energy to generate electron-hole pairs, and the electron-hole pairs are separated by the self-built electric field of the P-N junction inside the semiconductor, and the electrons flow into the N region and the holes flow into the P region, thereby forming a photovoltaic electric field. Generally speaking, the battery piece 100 is a sheet structure, and the side that can absorb light energy and convert it into electrical energy is called the light-absorbing side or the front side, and the other side is called the back side. The electrodes of the two polarities are formed on the back side of the solar cell, which is a back contact battery.

[0029] It can also be understood that in the battery string, the battery string can include two battery pieces 100 connected in series, three battery pieces 100 connected in series, or more battery pieces 100 connected in series, and the number of battery pieces 100 to be connected in series can be determined according to actual use.

[0030] Further, the form of the exposed area 301 formed by the insulating film 300 is not limited, and the solder strip 200 can be exposed, and the application does not limit the comparison. Illustratively, the insulating film 300 includes a plurality of spaced segment films, and the exposed area 301 can be formed between adjacent segment films. In this way, the segment film only covers the solder strip 200 that needs to be insulated, and the solder strip 200 welded with the bus bar 400 can be completely attached to the corresponding electrode area of the battery piece 100 due to the existence of the exposed area 301, so that the solder strip 200 can be connected with more fine grids. Preferably, the insulating film 300 is provided with a through hole 302 forming the exposed area 301. That is, the through hole 302 penetrates along the thickness direction of the insulating film 300 to form the exposed area 301. Among them, the insulating film 300 covers the solder strip 200, and because the insulating film 300 has the through hole 302, in this way, the through hole 302 can expose the solder strip 200 of the same polarity, so that the bus bar 400 can be connected with the solder strip 200 at the through hole 302, the insulating film 300 can prevent the bus bar 400 from short-circuiting the battery piece 100, and the insulating film 300 does not hinder the conductive connection between the bus bar 400 and the solder strip 200 due to the existence of the through hole 302, and it is convenient to completely attach the solder strip 200 to the battery piece 100, so that the solder strip 200 can be connected with more fine grids.

[0031] In this way, with reference to the visual angle when the back of the battery piece 100 is upward, the solder strip 200 is located on the side of the bus bar 400 facing the battery piece 100, so that even if the insulating film 300 is provided, the solder strip 200 can be completely attached to the electrode area, that is, the solder strip 200 can be connected with enough fine grids, fully utilize every fine grid on the battery piece 100, better collect current, and improve the effect of collecting current. It can be understood that this structure of the back contact battery assembly can effectively improve the current collection effect while hiding the bus bar 400.

[0032] In particular, the above structure of the application is more suitable for the battery piece 100 without a main grid. It can be understood that the battery piece 100 without a main grid means that the battery piece 100 is provided with a fine grid and does not have a main grid, and the solder strip 200 is directly arranged on the electrode area of the original main grid, and the current on the fine grid is directly exported through the electrical connection between the solder strip 200 and the fine grid. In this way, the more the part of the solder strip 200 attached to the battery piece 100, the more the fine grids connected, and the more the current exported. The less the part of the solder strip 200 attached to the battery piece 100, the less the fine grids connected, and the less the current exported. It can be understood that through the arrangement of the above structure, the bus bar 400 can be hidden at the back of the back contact battery assembly, so that the appearance color of the front of the assembly is consistent, such as achieving a full black effect, which is conducive to the full black design of the back contact battery assembly.

[0033] For example, the insulating film 300 can be an insulating adhesive, or a non-conductive tape or insulating film 300, such as a PET or PI tape with acrylic or silicone, or a PET or PI substrate coated with ethylene-vinyl acetate copolymer or hot melt adhesive on one or both sides. It is understood that the insulating film 300 may contain materials such as ethylene-vinyl acetate copolymer, resin materials, polyimide or polypropylene or polyethylene, and may also contain an acrylic adhesive layer.

[0034] like Figure 3 As shown in this embodiment, the busbar 400 has multiple protruding structures 401 and multiple connecting portions 402 connected between the protruding structures 401. The protruding structures 401 are the bent portions of the busbar 400, and the connecting portions 402 are the straight portions of the busbar 400. The protruding structures 401 extend into the exposed area 301 and make conductive connections with the exposed solder ribbon 200. This allows the protruding structures 401 to make closer contact with the solder ribbon 200, increasing the contact area, thereby reducing contact resistance and improving conductivity. This design helps reduce energy loss and improve the power generation efficiency of the battery module. Furthermore, the close contact between the protruding structures 401 and the solder ribbon 200 not only improves conductivity but also enhances the reliability of the connection. In harsh environments such as vibration and impact, this close connection can reduce circuit failures caused by loosening or detachment. The design of the protruding structures 401 makes the connection between the busbar 400 and the solder ribbon 200 more convenient. During the installation of the busbar 400, a conductive connection can be achieved simply by aligning the raised structure 401 with the exposed solder ribbon 200 and applying appropriate pressure and temperature. This allows for precise control of the local temperature of the busbar 400, preventing excessive heating of the busbar 400 from causing premature melting of the solder paste layer or adhesive film on the solder ribbon 200 within the battery module, which could lead to adhesion between the backsheet glass and the battery cells 100 and affect subsequent module assembly. Due to the special design of the busbar 400, the stable connection between the busbar 400 and the solder ribbon 200 facilitates filling the gaps in the exposed area 301 and improves the reliability of the battery module.

[0035] It should be noted that, based on the design of the busbar 400 with the raised structure 401, the thickness of the insulating film 300 can be 300-600 micrometers. Preferably, the thickness of the insulating layer is between 500-600 micrometers. In such embodiments, the thickness of the insulating layer can be 500 micrometers, 520 micrometers, 550 micrometers, 580 micrometers, 600 micrometers, or any value between 500 and 600 micrometers, and is not specifically limited here. Within this range, the insulating film 300 has good insulation effect, is easy to apply, is not easily deformed by pulling, and will not be damaged during long-term insulation. Furthermore, it can avoid the risk of short circuit caused by the burrs on the edge of the busbar 400 puncturing the insulating film 300.

[0036] In some embodiments, the top surface of the protruding structure 401 is a planar structure, and the protruding structure 401 and the solder strip 200 are in surface-to-surface contact. The connection between the bus bar 400 and the solder strip 200 is stable, the protruding structure 401 can be in closer contact with the solder strip 200, the contact area is increased, the contact resistance is reduced, the conduction efficiency is improved, and the lamination pressure is dispersed due to the surface-to-surface contact between the protruding structure 401 and the solder strip 200 during the lamination process, thereby reducing the risk of hidden cracks of the battery piece 100.

[0037] In some embodiments, the height of the protruding structure 401 is 300-800 microns. Preferably, the height of the protruding structure 401 is 500-800 microns. In such embodiments, the height of the protruding structure 401 can be 500 microns, 520 microns, 550 microns, 580 microns, 600 microns, 800 microns, or any value between 500 microns and 800 microns, which is not limited in particular herein. It can be understood that in some embodiments, the height of the protruding structure 401 and the thickness of the insulating film 300 are matched to achieve the protruding structure 401 partially extending into the insulating film 300, the other part of the bus bar 400 well adhering to the insulating film 300, reducing the generation of gaps, not entering air in the subsequent packaging process, and improving the reliability of the battery assembly.

[0038] In some embodiments, the outer peripheral wall of the protruding structure 401 and the inner peripheral wall of the through hole 302 are in close contact with each other. That is, there is no gap between the protruding structure 401 and the through hole 302, so that air does not enter after packaging, thereby improving the reliability of the battery assembly.

[0039] In some embodiments, the protruding structure 401 includes at least one of an arc shape, a rectangular shape, or a trapezoidal shape. The protruding structure 401 is arranged according to actual production needs, which is not limited in the present application. It should be noted that the protruding structure 401 of different shapes can be accurately matched with the through hole 302 of the corresponding shape to improve the accuracy and stability of the connection. For example, an arc-shaped protrusion can be matched with a circular through hole 302, a rectangular protrusion can be matched with a square through hole 302, and a trapezoidal protrusion can be matched with a trapezoidal through hole 302. Such accurate matching helps to reduce the assembly gap and improve the use reliability of the battery assembly.

[0040] The width of the insulating film 300 is greater than or equal to the width of the bus bar 400. If the width of the insulating film 300 is too narrow, the bus bar 400 will be exposed, and there is a risk of short circuit between the bus bar 400 and the female solder strip 200. The width of the insulating film 300 greater than or equal to the width of the bus bar 400 can completely isolate the bus bar 400 and the female solder strip 200, thereby avoiding the risk of short circuit.

[0041] The plurality of solder strips 200 extend in a first direction to connect the plurality of battery pieces 100 to form a battery string, and the plurality of bus bars 400 extend in a second direction to connect the plurality of battery strings, the insulating film 300 and the bus bars 400 extend in the same direction, and the insulating film 300 and the bus bars 400 are located at the middle of the battery pieces 100 at the end of the battery string. In this way, the transmission distance of the current can be effectively shortened, and the transmission loss of the solder strip 200 and the risk of edge cracking can be reduced.

[0042] The two adjacent battery pieces 100 are partially overlapped. The plurality of battery pieces 100 are partially overlapped to form a battery string, and the contact area between the overlaps is not conductively connected, that is, the overlap area does not need to be provided with conductive glue or other adhesive glue, and the battery pieces 100 are only overlapped together. Among them, the overlap area of the adjacent battery pieces 100 in the battery string is provided with a solder strip 200 to fixedly connect the adjacent battery pieces 100. In this way, the battery piece 100 and the battery piece 100 do not have a gap, so that the solder strip 200 can be better hidden, and the size of the battery string can be reduced by the overlap between the battery pieces 100, thereby making the battery string occupy less space. Or, in the case of a certain size of the battery string, more battery pieces 100 can be placed, the power of the battery string is improved, and the cost per watt is reduced.

[0043] It can be understood that the partial overlap of the plurality of battery pieces 100 in the battery string means that the adjacent battery pieces 100 in the battery string overlap a part of the area. Among them, the overlap width range can be 0mm to 0.5mm, such as 0mm, 0.1mm, 0.2mm, 0.4mm or 0.5mm, which is not limited in the present application.

[0044] A photovoltaic system includes the above-mentioned back contact battery assembly. In the present embodiment, the photovoltaic system can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus that generates electricity by using solar energy, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that need to generate electricity by using solar energy. Taking a photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a bus box and an inverter, the photovoltaic array can be an array combination of a plurality of battery assemblies, for example, a plurality of battery assemblies can form a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the bus box, the bus box can converge the current generated by the photovoltaic arrays, the converged current flows through the inverter to convert into alternating current required by the power grid, and then is connected to the power grid to realize solar power supply.

[0045] In the description of the application, reference to "some embodiments", "certain embodiments", "exemplary", "specific", or "some examples", etc., indicate that the described features, structures, materials, or characteristics are included in at least one embodiment or example of the application. These embodiments need not necessarily be mutually exclusive; in addition, the specific features, structures, materials, or characteristics in each embodiment can be combined in any suitable manner in other embodiments. Moreover, the specific features, structures, materials, or characteristics can be combined in any suitable manner in other embodiments or examples without departing from the spirit and scope of the application.

[0046] The above description is merely illustrative of the application, and is not to be taken in a limiting sense. Any modification, equivalent replacement, and improvement made within the spirit and principle of the application should be included in the scope of the application.

Claims

1. A back contact cell assembly, characterized by, The back contact battery assembly comprises: a plurality of battery pieces; a plurality of solder strips connecting two adjacent battery pieces; an insulating film on the side of the solder strips away from the battery pieces, the insulating film being formed with a plurality of exposed areas exposing the solder strips of the same polarity; and 2. The back contact solar cell assembly of claim 1, wherein, a bus bar disposed on the side of the insulating film away from the battery pieces, the bus bar comprising a plurality of protruding structures and a plurality of connecting portions connecting the protruding structures, the protruding structures respectively extending into the corresponding exposed areas to electrically connect with the exposed solder strips; the insulating film is provided with through holes forming the exposed areas, and the outer peripheral wall of the protruding structures and the inner peripheral wall of the through holes are in close contact with each other.

3. The back contact solar cell assembly of claim 1, wherein, The top surface of the protruding structure is a planar structure, and the protruding structure and the solder strip are in surface-to-surface contact.

4. The back contact solar cell assembly of claim 1, wherein, The thickness of the insulating film is 300-600 microns.

5. The back contact solar cell assembly of claim 1, wherein, The height of the protruding structure is 300-800 microns.

6. The back contact solar cell assembly of claim 1, wherein, The protruding structure comprises at least one of an arc shape, a rectangular shape, or a trapezoidal shape.

7. The back contact solar cell assembly of claim 1 wherein, The width of the insulating film is greater than or equal to the width of the bus bar.

8. The back contact solar cell assembly of claim 1 wherein, The plurality of solder strips extend in a first direction to connect the plurality of battery pieces to form a battery string, and the bus bar extends in a second direction to connect a plurality of battery strings, the insulating film and the bus bar extending in the same direction, the insulating film and the bus bar being located in the middle of the battery pieces at the end of the battery string.

9. A photovoltaic system characterized by, The two adjacent battery pieces are partially overlapped. The back contact battery assembly comprises any one of claims 1-8. The back contact battery assembly comprises any one of claims 1-8.

Images