Back contact photovoltaic cell and method of manufacturing same, stacked cell and photovoltaic module

Abstract

The embodiment of the present application relates to the field of photovoltaic cells, and provides a back contact photovoltaic cell, a manufacturing method thereof, a laminated cell and a photovoltaic module, the back contact photovoltaic cell comprising: a cell body having opposite first and second surfaces; a plurality of main grids arranged on the first surface, the main grids extending along a second direction, and the main grids being arranged in sequence along a first direction; the second direction intersecting the first direction; a plurality of fine grids arranged on the first surface, the fine grids extending along the first direction, and the fine grids being disconnected at positions of the main grids; a plurality of connecting pieces arranged on the first surface, the connecting pieces being arranged on the straight line of the main grids; part of the connecting pieces being connected with the main grids, and part of the connecting pieces being arranged in the second direction and spaced apart from the main grids; and the connecting pieces being arranged in line with the fine grids and connected with the fine grids at the positions where the fine grids are disconnected. The embodiment of the present application can at least solve the problems of fine grid disconnection, welding disconnection and virtual welding.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cells, and in particular to a back-contact photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module. Background Technology

[0002] With the gradual depletion of fossil fuels, photovoltaic (PV) cells are becoming increasingly widely used as a new energy alternative. A PV cell is a device that converts solar energy into electrical energy. PV cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy. To further reduce the shading of the front side of PV cells by the grid lines, research on BC cells (Back Contact) is becoming increasingly in-depth.

[0003] The most significant feature of BC batteries is that the PN junction and contact metal are both located on the back of the BC battery. The front of the BC battery completely avoids the obstruction of the metal grid electrodes, which can maximize the use of incident light, reduce optical loss, and have a higher short-circuit current.

[0004] In related technologies, the metal electrodes of BC batteries are usually manufactured by forming a main grid first and then a fine grid, and the fine grid penetrates the main grid of the same electrical charge to make the two electrically connected. Summary of the Invention

[0005] This application provides a back-contact photovoltaic cell and its manufacturing method, a tandem cell, and a photovoltaic module, which at least helps to solve the problems of broken grids and broken or incomplete welds.

[0006] According to some embodiments of this application, one aspect of this application provides a back-contact photovoltaic cell, comprising: a cell body having opposing first and second surfaces; a main grid, wherein a plurality of main grids are disposed on the first surface, the main grids extending along a second direction, and the plurality of main grids are arranged at intervals along a first direction; the second direction intersects the first direction; a fine grid, wherein a plurality of fine grids are disposed on the first surface, the fine grids extending along the first direction, and the fine grids are interrupted at the line positions where the main grids are located; and a plurality of connectors are disposed on the first surface, the connectors being disposed on the line positions where the main grids are located; some of the connectors are connected to the main grids, and some of the connectors are spaced apart from the main grids in the second direction;

[0007] The connector is arranged collinearly with the fine grid and connects to the fine grid at the position where the fine grid is disconnected.

[0008] In some embodiments, the connector includes: a connector body extending along a first direction; and overlapping portions disposed at both ends of the connector body; the overlapping portions are symmetrically arranged with the straight line of the connector body as the center line; wherein the fine grid is connected to the overlapping portions.

[0009] In some embodiments, the overlap extends along the second direction.

[0010] In some embodiments, in the first direction, the width of the overlapping portion is a first width W1; in the second direction, the width of the fine grid is N1, satisfying 0.8≤W1 / N1≤1.2.

[0011] In some embodiments, the first width W1 of the overlapping portion satisfies 10μm≤W1≤100μm.

[0012] In some embodiments, in the second direction, the width of the fine grid is the fine grid width N1, and the width of the connector body is the second width W2, satisfying that 1≤N1 / W2≤2.5.

[0013] In some embodiments, the first surface includes a first region and a second region alternately disposed sequentially along the second direction, the first region and the second region extending discontinuously along the first direction; fine grids of different polarities are respectively disposed in the first region and the second region;

[0014] In the second direction, the width of the first region is the width of the first region D1, the width of the second region is the width of the second region D2, and the length of the overlapping part is the overlapping length L3, satisfying that 0.2≤L3 / D1≤1 and 0.2≤L3 / D2≤1.

[0015] In some embodiments, the overlap length L3 of the overlapping portion satisfies 50μm≤L3≤560μm.

[0016] In some embodiments, in the first direction, the width of the main gate is the main gate width N2; in the second direction, the width of the connector body is the second width W2, satisfying 0.8≤N2 / W2≤1.2.

[0017] In some embodiments, the second width W2 of the connector body satisfies 10μm≤W2≤560μm.

[0018] In some embodiments, the connector includes a first connector and a second connector;

[0019] The first connector includes: a first connector body extending along the first direction and a first overlapping portion disposed at both ends of the first connector body and extending along the second direction; the first connector body intersects and connects with the main grid;

[0020] The second connector includes: a second connector body extending along a first direction and second overlapping portions disposed at both ends of the second connector body and extending along the second direction; the second connector body is spaced apart from the main grid in the second direction.

[0021] The fine gate connected to the second connector has a different characteristic from the main gate that is spaced apart from it.

[0022] In some embodiments, in the first direction, the length of the first connector body is a first length L1, and the length of the second connector body is a second length L2, satisfying that 3≤L2 / L1≤8.

[0023] In some embodiments, 200μm≤L1≤600μm, 200μm≤L2≤1200μm.

[0024] In some embodiments, the main gate and the portion of the connector to which it is connected are an integral structure.

[0025] According to some embodiments of this application, another aspect of this application also provides a method for manufacturing a back-contact photovoltaic cell, comprising: providing a cell body having opposing first and second surfaces;

[0026] A main grid and connectors are formed on the first surface. The main grid extends along a second direction, and a plurality of main grids are arranged at intervals along a first direction. The second direction intersects the first direction. Some of the connectors are connected to the main grids, and some of the connectors are spaced apart along the second direction.

[0027] Fine grids are formed on the first surface to obtain a back-contact photovoltaic cell; the fine grids extend discontinuously along the first direction, and a plurality of the fine grids are arranged at intervals along the second direction; wherein, the fine grids are broken at the positions of the main grids, and the broken fine grids are connected by the connector.

[0028] According to some embodiments of this application, another aspect of this application also provides a stacked battery, including:

[0029] The back contact photovoltaic cell is a back contact photovoltaic cell as described above, or the back contact photovoltaic cell is manufactured by the manufacturing method of the back contact photovoltaic cell as described above.

[0030] A thin-film battery, wherein the thin-film battery is disposed on the side of the back contact photovoltaic cell.

[0031] According to some embodiments of this application, another aspect of this application also provides a photovoltaic module, including:

[0032] A battery string, wherein the battery string is composed of a plurality of back-contact photovoltaic cells or stacked cells connected together, wherein the back-contact photovoltaic cell is a back-contact photovoltaic cell as described above, or the back-contact photovoltaic cell is manufactured by the back-contact photovoltaic cell manufacturing method as described above, and the stacked cell is a stacked cell as described above.

[0033] Solder strips, which connect adjacent back-contact photovoltaic cells or stacked cells;

[0034] An encapsulating film that covers the surface of the back contact photovoltaic cell;

[0035] A cover plate located on the surface of the encapsulating film away from the back contact photovoltaic cell.

[0036] The technical solution provided by the embodiments of this application has at least the following advantages: On the one hand, by disconnecting the fine gate at the main gate or at the position where the main gate extends in a straight line, and connecting the fine gates on both sides of the disconnection with a connector, the overlapping structure of the fine gate and the main gate in the related technology is avoided, thereby avoiding the problem of fine gate breakage caused by the height difference between the fine gate and the main gate surface, and avoiding the problem of welding breakage and poor welding caused by the fine gate increasing the height of the main gate surface.

[0037] On the other hand, the connection components ensure that the surface of the main grid and the surface of the connection components intersecting with the main grid or the surface of the connection components on the extension line of the main grid are of the same height. This makes the weld strip after welding fit more closely with the surface of the main grid or the surface of the connection components. It avoids the problem of local depressions in the weld strip caused by the protrusion formed by the overlap of the fine grid and the main grid in some areas abutting the surface of the weld strip or the fine grid being too small. This avoids excessive local stress or insufficient support in the weld strip and further avoids the problem of broken or poor welding between the weld strip and the back contact photovoltaic cell. Attached Figure Description

[0038] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a back-contact photovoltaic cell provided in an embodiment of this application;

[0040] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0041] Figure 3 This application illustrates a method for manufacturing a back-contact photovoltaic cell according to an embodiment of the present application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 100. Cell body; 110. First surface; 111. First region; 112. Second region; 200. Main grid; 210. First main grid; 211. First connecting line; 220. Second main grid; 221. Second connecting line; 300. Fine grid; 310. First fine grid; 311. First busbar fine grid; 312. First current collector fine grid; 320. Second fine grid; 321. Second busbar fine grid; 322. Second current collector fine grid; 400. Connector; 401. Connector body; 402. Overlap; 410. First connector; 411. First connector body; 412. First overlap; 420. Second connector; 421. Second connector body; 422. Second overlap; 500. Welded part. Detailed Implementation

[0044] As is known from the background art, the metal electrodes of BC batteries are usually manufactured by forming a main grid first and then a fine grid, and the fine grid penetrates the main grid of the same electrical charge to make the two electrically connected.

[0045] However, because the main gate is larger than the fine gate, it is thicker, resulting in a height difference at the main gate when the fine gate is formed. This height difference has a high probability of causing the fine gate to break. Furthermore, after the fine gate penetrates the main gate, it increases the surface height of the overlapping area, forming a protrusion. When the solder ribbon is soldered to the pads on the main gate, this protrusion prevents the solder ribbon from adhering tightly to the surface of the solder joint, increasing the risk of solder paste breakage and cold solder joints during the soldering connection.

[0046] This application provides a back-contact photovoltaic cell. By disconnecting the fine grid at the main grid or along the straight extension direction of the main grid, and connecting the two disconnected fine grids with connectors, the overlapping structure of the fine grid and the main grid in related technologies is avoided. This avoids the problem of fine grid breakage caused by the height difference between the fine grid and the main grid surface, and also avoids the problem of weld breakage or cold solder joints caused by the fine grid increasing the height of the main grid surface. Furthermore, the connector ensures that the surface of the main grid and the surface of the connector intersecting with the main grid or the surface of the connector on the extension line of the main grid are of consistent height. This makes the weld strip more closely fit the surface of the main grid or the surface of the connector after welding, and avoids the problem of local depressions in the weld strip caused by the overlap of the fine grid and the main grid abutting the surface of the weld strip or the fine grid being too small. This avoids excessive local stress or insufficient support in the weld strip, and further avoids the problem of weld breakage or cold solder joints between the weld strip and the welded part.

[0047] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets, and "multiple pieces" refers to two or more pieces.

[0048] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0049] In the description of the embodiments in this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or N can represent three cases: A exists, A and N exist simultaneously, and N exists. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.

[0050] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may cover both above and below orientations depending on the context in which the term is used, which will be obvious to those skilled in the art. Materials may be oriented in other ways, and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0051] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0052] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. Furthermore, when describing a component as "generally" formed on another component, it means that the component is not formed on the entire surface of the other component, nor is it formed on a portion of the edge of the entire surface.

[0053] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. The formation or provision of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be present between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or provision of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" may refer to a layer, film, region, portion, structure, etc.

[0054] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0055] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0056] Figure 1 This is a schematic diagram of the structure of a back-contact photovoltaic cell provided in an embodiment of this application.

[0057] refer to Figure 1 The back-contact photovoltaic cell includes: a cell body 100, the cell body 100 having opposing first surfaces 110 and second surfaces;

[0058] A main gate 200, a plurality of main gates 200 are disposed on the first surface 110, the main gates 200 extend along a first direction, and the plurality of main gates 200 are arranged sequentially at intervals along a second direction; the first direction and the second direction intersect.

[0059] Fine grid 300, a plurality of fine grids 300 are disposed on the first surface 110, the fine grids 300 extend along the second direction, and the fine grids 300 are interrupted at the straight line position where the main grid 200 is located;

[0060] A plurality of connectors 400 are disposed on the first surface 110 and are disposed on the straight line where the main grid 200 is located; some connectors 400 are connected to the main grid 200 and some connectors 400 are spaced apart from the main grid 200 in the first direction.

[0061] The connecting line of the connector 400 is arranged collinearly with the fine grid 300 and is connected to the fine grid 300 at the position where the fine grid 300 is disconnected.

[0062] In this embodiment, the fine grid 300 is broken at the straight line position of the main grid 200. The broken fine grids 300 are connected by the connector 400, which avoids the overlapping structure of the fine grid 300 and the main grid 200 in the related art. This avoids the fine grid 300 breaking due to the large height difference between the surface of the fine grid 300 and the main grid 200, and avoids the fine grid 300 and the main grid 200 overlapping to form a protrusion, making the surface of the main grid 200 uneven and making it difficult for the solder strip to adhere to the surface of the main grid 200, which in turn leads to the problem of broken welds and poor welds in the welding connection between the welding part 500 and the solder strip. Furthermore, the connector 400 in the extension direction of the main gate 200 replaces the fine gate 300 in the related technology. The connector 400 connected to the main gate 200 and the connector 400 in the extension direction of the main gate 200 with different polarity from the main gate 200 have the same surface height, which further improves the flatness of the surface of the main gate 200 and the surface in the extension direction of the main gate 200, improves the adhesion between the solder strip and the surface of the main gate 200, and thus avoids the problem of broken welding and poor welding between the solder strip and the welding part 500.

[0063] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0064] like Figure 1 As shown, the back-contact photovoltaic cell includes: a cell body 100, a main grid 200, a fine grid 300, a connector 400, and a welding part 500. The main grid 200 and the fine grid 300 are used to collect and transport charge carriers, and the welding part 500 is disposed on the main grid 200 or the fine grid 300 for welding connection with the welding strip and for transporting charge carriers to the welding strip.

[0065] In some embodiments, the back contact photovoltaic cell is a BC cell. The BC cell can be an IBC cell (Interdigitated Back Contact), an HPBC cell (Hybrid Passivated Back Contact), a TBC cell that combines TOPCon (Tunnel Oxide Passivated Contact) technology and IBC technology, or an HBC cell that combines HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back contact photovoltaic cells.

[0066] In some embodiments, the type of back-contact photovoltaic cell can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0067] The cell body 100 has intersecting and perpendicular first direction, second direction, and third direction, the third direction being the thickness direction of the cell body 100. The cell body 100 has opposing first surface 110 and second surface in the third direction. The main grid 200, fine grid 300, connector 400, welding part 500, and connecting line are disposed on the first surface 110 of the cell body 100.

[0068] In some embodiments, the battery cell body 100 may be divided into 1 / N whole battery cells, that is, the battery cell body 100 is divided into N pieces, where N is a positive integer greater than 1; in other embodiments, the battery cell body 100 may also be composed of whole battery cells, that is, the battery cell body 100 is a whole piece.

[0069] In some examples, the cell body 100 is divided into 1 / 2 whole cells, that is, the cell body 100 is divided into two pieces.

[0070] It should be noted that the back-contact photovoltaic cell can be a single-sided cell, and the second surface can be considered as the front side of the back-contact photovoltaic cell, serving as the light-receiving surface for receiving incident light, while the first surface 110 is the back-lighting surface; alternatively, the final back-contact photovoltaic cell can be a bi-sided cell, in which case both the first surface 110 and the second surface can serve as light-receiving surfaces and can be used to receive incident light. It is understood that the back-lighting surface described in the embodiments of this application can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a back-lighting surface.

[0071] The main grid 200 is disposed on the first surface 110 of the cell body 100. The main grid 200 includes a first main grid 210 and a second main grid 220 with different polarities. The first main grid 210 and the second main grid 220 extend along a second direction. The first main grid 210 and the second main grid 220 are alternately arranged in a first direction.

[0072] A fine grid 300 is disposed on the first surface 110 of the battery cell body 100. The fine grid 300 includes a first fine grid 310 and a second fine grid 320 with different polarities. The first fine grid 310 and the second fine grid 320 extend along a first direction, and are alternately arranged in a second direction. The first main grid 210 and the first fine grid 310 have the same polarity, and the second main grid 220 and the second fine grid 320 have the same polarity. The first main grid 210 is either positive or negative, and the second main grid 220 is either positive or negative. The first fine grid 310 and the second fine grid 320 terminate at the position of the main grid 200 or in the direction of the main grid 200's extension, so that the main grid 200 or the line containing the main grid 200 passes through the termination point of the first fine grid 310 or the second fine grid 320. The first fine grid 310 is disconnected at the second main grid 220 with a different polarity, and the second fine grid 320 is disconnected at the first main grid 210 with a different polarity, to ensure insulation between the fine grid 300 and the main grid 200 with different polarities, and to avoid short circuits caused by contact connection between the fine grid 300 and the main grid 200 with different polarities, which would lead to a decrease in the photoelectric conversion efficiency of the back contact photovoltaic cell.

[0073] A connector 400 is disposed on the first surface 110 of the cell body 100. The connector 400 is disposed at the position where the fine grid 300 of the same polarity intersects with the main grid 200, or at the position where the fine grid 300 intersects with the extension line of the main grid 200 of different polarity. Some connectors 400 connect the disconnected fine grid 300 and intersect with the main grid 200 of the same polarity to make the main grid 200 and the fine grid 300 of the same polarity electrically connected. Other connectors 400 connect the disconnected fine grid 300 and are spaced apart from the main grid 200 of different polarity in the second direction to insulate and isolate the fine grid 300 and the main grid 200 of different polarity.

[0074] In some embodiments, the first fine gate 310 includes a first busbar fine gate 311 and a first collector fine gate 312 extending discontinuously along a first direction, and the second fine gate 320 includes a second busbar fine gate 321 and a second collector fine gate 322 extending discontinuously along the first direction. A pair of first collector fine gates 312 and second collector fine gates 322 with different polarities are arranged opposite to each other in a second direction, and multiple first busbar fine gates 311 and second busbar fine gates 321 are arranged alternately in sequence along the second direction between the first collector fine gates 312 and the second collector fine gates 322. Multiple first main grids 210 and multiple second main grids 220 extending along the second direction are disposed between the aforementioned opposing first current collector grids 312 and second current collector grids 322, and are arranged alternately in sequence along the first direction. The first main grid 210 passes through the break point of the first current collector grid 311 with the same polarity and the break point of the second current collector grid 321 with a different polarity. The second main grid 220 passes through the break point of the second return grid 300 with the same polarity and the break point of the first current collector grid 311 with a different polarity.

[0075] A connector 400 is disposed at the break point where the first main gate 210 passes through the first busbar 311 with the same polarity. The connector 400 is cross-contacted with the first main gate 210, and the two ends of the connector 400 in the first direction are connected to the first busbar 311, so that the first main gate 210 and the first busbar 311 are electrically connected through the connector 400. The charge carriers collected by the first busbar 311 are transported to the first main gate 210 through the connector 400. A portion of the connector 400 is disposed at the break point where the second main gate 220 passes through the second busbar 321 with the same polarity. The connector 400 is cross-contacted with the second main gate 220, and the two ends of the connector 400 in the first direction are connected to the second busbar 321, so that the second main gate 220 and the second busbar 321 are electrically connected. The charge carriers collected by the second busbar 321 are transported to the second main gate 220 through the connector 400. In this embodiment, the disconnected fine gate 300 is connected by the connector 400, eliminating the overlapping structure in the formation process of the fine gate 300 and the main gate 200 in the related technology, thereby avoiding the gate breakage problem caused by the excessive height difference between the surface of the fine gate 300 and the main gate 200.

[0076] The first current collector 312 extends intermittently along the first direction. The first current collector 312 is broken at the intersection of the extension line of the second main gate 220 with a different polarity and at the intersection of the first main gate 210 with the same polarity. The connector 400 is disposed at the broken position of the first current collector 312. The two ends of the connector 400 about the first direction are in contact with the broken first current collector 312 to form a continuously conducting circuit in the first direction. The connector 400, located at the intersection of the extension lines of the first current collector 312 and the second main gate 220, is spaced apart from the second main gate 220 in the second direction to ensure that the first current collector 312 and the second main gate 220 are insulated from each other. The connector 400, located at the intersection of the first current collector 312 and the first main gate 210, electrically connects the first current collector 312 and the first main gate 210. The charge carriers collected by the first current collector 312 are transmitted to the first main gate 210 through the connector 400. The first main gates 210 with the same polarity can be interconnected through the first current collector 312, thereby reducing the overall internal resistance of the first current collector 310 and the first main gate 210 and improving the carrier transmission efficiency.

[0077] The second current collector 322 extends discontinuously along the second direction. The second current collector 322 is disconnected at the intersection of the extension line of the first main gate 210 with a different polarity and at the intersection of the extension line of the second main gate 220 with the same polarity. The connector 400 is disposed at the disconnected position of the second current collector 322. The two ends of the connector 400 with respect to the first direction are in contact with the disconnected second current collector 322 to form a continuously conductive circuit in the first direction. The connector 400, located at the intersection of the extension lines of the second current collector 322 and the first main gate 210, is spaced apart from the first main gate 210 in the second direction to ensure that the second current collector 322 and the first main gate 210 are insulated from each other. The connector 400, located at the intersection of the second current collector 322 and the second main gate 220, electrically connects the second current collector 322 and the second main gate 220. The charge carriers collected by the second current collector 322 are transmitted to the second main gate 220 through the connector 400. The second main gates 220 with the same polarity can be interconnected through the second current collector 322, thereby reducing the overall internal resistance of the second current collector 320 and the second main gate 220 and improving the carrier transmission efficiency.

[0078] In this embodiment, the connector 400 connects to the fine grid 300 that is disconnected at the extension of the main grid 200. The connector 400 is larger than the fine grid 300, which makes the surface of the main grid 200 and the surface on its extension line larger. This avoids the fine grid 300 on the extension line of the main grid 200 being too small, which would result in insufficient support for the solder strip or even local depression of the solder strip. It also avoids the problem of poor soldering or broken soldering caused by excessive local stress on the solder strip, improves the connection effect between the solder strip and the back contact photovoltaic cell, and thus improves the reliability of the back contact photovoltaic cell.

[0079] Combination Figure 2 As shown, Figure 2 It shows Figure 1 A magnified structural diagram of point A in the middle.

[0080] In some embodiments, the connector 400 includes a connector body 401 and overlapping portions 402. The connector body 401 extends along a first direction, and a pair of overlapping portions 402 are respectively disposed at both ends of the connector body 401 about the first direction. In a second direction, the size of the overlapping portion 402 is larger than the size of the connector body 401, and the overlapping portions 402 are symmetrically arranged about the straight line containing the connector body 401 as the center line. In other words, the overlapping portions 402 are symmetrically arranged at both ends of the connector 400 about the first direction along the second direction, so that the overlapping portions 402 have a certain size in the second direction. The overlapping portions 402 having a certain size in the second direction prevent the fine grid 300 or the connector 400 from intersecting due to tolerances in the second direction, thus avoiding the risk of grid breakage when connecting the fine grid 300 and the connector 400, and improving the reliability of the back contact photovoltaic cell.

[0081] Furthermore, the connector 400 and the main grid 200 are an integral structure. In other words, during the manufacturing process of the back contact photovoltaic cell, the connector 400 and the main grid 200 are integrally formed in the same step, so that the surface of the connector 400 and the surface of the main grid 200 are on the same plane. This ensures that the surface height of the main grid 200 or the connector 400 is consistent, improves the adhesion between the surface of the main grid 200 and the solder strip, facilitates the welding connection between the solder strip and the back contact photovoltaic cell, and improves the stability of the structure after welding connection, thereby improving the reliability of the back contact photovoltaic cell.

[0082] In some embodiments, the overlapping portion 402 is a rectangular shape extending along the second direction. In other embodiments, the orthographic projection of the overlapping portion 402 is a triangle, a circle, a square, or other shapes, which are not specifically limited here.

[0083] In some embodiments, when the overlapping portion 402 is a rectangular shape extending along the second direction, the width of the overlapping portion 402 in the first direction is a first width W1; and in the second direction, the width of the fine grid 300 is the width N1 of the fine grid 300, satisfying 0.8 ≤ W1 / N1 ≤ 1.2. Optionally, the ratio W1 / N1 between the first width W1 of the overlapping portion 402 and the width N1 of the fine grid is 0.9 to 1.1, and the ratio W1 / N1 between the first width W1 of the overlapping portion 402 and the width N1 of the fine grid can be 0.9, 0.95, 1.0, 1.05, or 1.1. The first width W1 of the overlap portion 402 is similar to the width N1 of the fine gate 300, ensuring a more uniform resistance distribution in the carrier transport path between the fine gate 300 and the overlap portion 402. This avoids carrier transport bottlenecks and increased local power loss caused by an excessively narrow overlap portion 402, or increased production costs due to an excessively wide overlap portion 402 leading to increased light-shielding area and excessive paste usage. In some embodiments, the first width W1 of the overlap portion 402 satisfies 10μm≤W1≤100μm. Optionally, the first width W1 of the overlap portion 402 is 20μm~90μm, and can be 30μm, 40μm, 60μm, or 80μm.

[0084] In some embodiments, when the overlapping portion 402 is a rectangular shape extending along the second direction, the width N1 of the fine gate 300 and the width W2 of the connector body 401 satisfy 1 ≤ N1 / W2 ≤ 2.5. Optionally, the ratio between the width N1 of the fine gate 300 and the second width W2 of the connector body 401 is 1.2 to 2, and the ratio can be 1.2, 1.4, 1.6, 1.8, or 2. The width of the connector body 401 is greater than the width of the fine gate 300 to ensure the transmission efficiency of charge carriers when passing through the connector 400, and to avoid the internal resistance being too high due to the width of the connector body 401 being too small, thereby reducing the transport efficiency of charge carriers.

[0085] Reference Figure 2 As shown, the first surface 110 of the solar cell body 100 includes a first region 111 and a second region 112 alternately arranged along a second direction. The first region 111 and the second region 112 extend along the first direction, and a first fine gate 310 and a second fine gate 320 with different polarities are respectively disposed in the first region 111 and the second region 112. The first region 111 and the second region 112 correspond to doped semiconductor layers with different doping element types in the solar cell body 100. An isolation region is also provided at the junction of the first region 111 and the second region 112 to insulate and isolate the doped semiconductor layers with different doping element types.

[0086] In some embodiments, in the second direction, the width of the first region 111 is the first region width D1, the width of the second region 112 is the second region width D2, and the length of the overlap 402 is the overlap length L3, satisfying 0.2≤L3 / D1≤1. Optionally, the ratio L3 / D1 between the overlap length L3 of the overlap 402 and the first region width D1 of the first region 111 is 0.4≤L3 / D1≤0.8, and the ratio L3 / D1 between the overlap length L3 of the overlap 402 and the first region width D1 of the first region 111 can be 0.4, 0.5, 0.6, 0.7, or 0.8.

[0087] In some embodiments, in the second direction, the width of the second region 112 is the second region width D2, and the length of the overlap 402 is the overlap length L3, satisfying 0.2 ≤ L3 / D2 ≤ 1. Optionally, the ratio L3 / D2 between the overlap length L3 of the overlap 402 and the second region width D2 of the second region 112 is 0.4 ≤ L3 / D2 ≤ 0.8, and the ratio L3 / D2 between the overlap length L3 of the overlap 402 and the second region width D2 of the second region 112 can be 0.4, 0.5, 0.6, 0.7, or 0.8.

[0088] In the second direction, the length of the overlap portion 402 is less than the length of the first region 111 or the second region 112, to prevent the overlap portion 402 from crossing the first region 111 and the second region 112 and causing a short circuit between them, thus improving the reliability of the back contact photovoltaic cell. Furthermore, the overlap portion 402 has a certain width in the second direction to facilitate contact and connection between the overlap portion 402 and the fine grid 300, which may not have made contact with the overlap portion 402 due to manufacturing tolerances.

[0089] In some embodiments, the length of the overlapping portion 402 is the overlapping length L3, which satisfies 50μm≤L3≤560μm. Optionally, the overlapping length L3 of the overlapping portion 402 is 100μm~500μm, and the overlapping length L3 of the overlapping portion 402 can be 200μm, 300μm, 350μm or 400μm.

[0090] In some embodiments, in a first direction, the width of the main gate 200 is the main gate width N2; in a second direction, the width of the connector body 401 is the second width W2, satisfying 0.8 ≤ N2 / W2 ≤ 1.2. Optionally, the ratio N2 / W2 between the main gate width N2 of the main gate 200 and the second width W2 of the connector body 401 is 0.9~1.1, and the ratio N2 / W2 between the main gate width N2 of the main gate 200 and the second width W2 of the connector body 401 can be 0.9, 0.95, 1.0, or 1.05. The width of the connector body 401 is close to the width of the main gate, ensuring a more uniform resistance distribution in the carrier transport path between the main gate 200 and the connector body 401, avoiding carrier transport bottlenecks and increased local power loss caused by an excessively narrow width of the connector body 401, or avoiding increased light-shielding area and excessive paste usage leading to increased production costs due to an excessively wide width of the connector body 401. In some embodiments, the second width W2 of the connector body 401 satisfies 10μm≤W2≤560μm. Optionally, the second width W2 of the connector body 401 is 100μm~500μm, and the second width W2 of the connector body 401 can be 200μm, 300μm, 350μm or 400μm.

[0091] Reference Figure 2 As shown, the connector 400 includes a first connector 410 and a second connector 420. The first connector 410 is located at a point where the fine gate 300 is disconnected from the main gate 200, which has the same polarity, and the second connector 420 is located at a point where the fine gate 300 is disconnected from the extension line of the main gate 200, which has a different polarity.

[0092] In some embodiments, the first connector 410 is disposed at the position where the first busbar 311 is disconnected at the first main gate 210, the first collector busbar 312 is disconnected at the first main gate 210, the second busbar 321 is disconnected at the second main gate 220, and the second collector busbar 322 is disconnected at the second main gate 220. The second connector 420 is disposed at the position where the first collector busbar 312 is disconnected at the intersection of the extended line of the second main gate 220 and the position where the second collector busbar 322 is disconnected at the intersection of the extended line of the first main gate 210.

[0093] The first connector 410 includes a first connector body 411 and a first overlapping portion 412. The first connector body 411 extends along a first direction, and the first overlapping portion 412 is disposed at both ends of the first connector body 411 about the first direction. The first connector body 411 intersects and contacts the main gate 200. The second connector 420 includes a second connector body 421 and a second overlapping portion 422. The second connector body 421 extends along the first direction, and the second overlapping portion 422 is disposed at both ends of the second connector body 421 about the first direction. The second connector body 421 is spaced apart from its corresponding main gate 200 in a second direction.

[0094] In some embodiments, in the first direction, the length of the first connector body 411 is a first length L1, and the length of the second connector body 421 is a second length L2, satisfying 3 ≤ L2 / L1 ≤ 8. Optionally, the ratio between the second length L2 of the second connector body 421 and the first length L1 of the first connector body 411 is 4 to 7, and the ratio can be 4, 5, 6, or 7. The second length L2 of the second connector body 421 is greater than the first length L1 of the first connector body 411, which increases the contact area between the second connector 420 and the welding strip, increases the supporting force of the second connector 420 on the welding strip, facilitates the welding connection between the welding strip and the back contact photovoltaic cell, improves the structural stability after the back contact photovoltaic cell and the welding strip are connected, and thus improves the reliability of the back contact photovoltaic cell.

[0095] In some embodiments, the first length L1 of the first connector body 411 satisfies 200μm≤L1≤600μm. Optionally, the first length L1 of the first connector body 411 is 300μm~500μm, and the first length L1 of the first connector body 411 can be 350μm, 400μm, 450μm or 480μm.

[0096] In some embodiments, the second length L2 of the second connector body 421 satisfies 200μm≤L2≤1200μm. Optionally, the second length L2 of the second connector body 421 is 300μm~1100μm, and the second length L2 of the second connector body 421 can be 400μm, 600μm, 800μm or 1000μm.

[0097] Continue to refer to Figure 1As shown, the back-contact photovoltaic cell also includes a first connecting line 211 and a second connecting line 221. The main bodies of the first connecting line 211 and the second connecting line 221 extend along the second direction. The first connecting line 211 and the second connecting line 221 are respectively located at the edge positions of the cell body 100 on both sides with respect to the second direction. The first connecting line 211 is in contact with a portion of the first current-collecting grid 311 and the first current-collecting grid 312. The second connecting line 221 is in contact with a portion of the second current-collecting grid 321 and the second current-collecting grid 322. A welding portion 500 is provided on at least one first busbar 311 that is in contact with the first connecting line 211, and a welding portion 500 is provided on at least one second busbar 321 that is in contact with the second connecting line 221. The welding portion 500 provided on the first busbar 311 or the second busbar 321 avoids the welding portion 500 being too close to the edge of the cell body 100, and prevents the edge of the cell body 100 from cracking due to excessive internal stress after the welding portion 500 is connected to the welding strip. This improves the reliability of the back contact photovoltaic cell and extends the service life of the back contact photovoltaic cell.

[0098] Accordingly, another embodiment of this application also provides a method for manufacturing a back-contact photovoltaic cell, which can be used to manufacture the back-contact photovoltaic cell provided in the above embodiments. The manufacturing method of the back-contact photovoltaic cell provided in another embodiment of this application will be described in detail below with reference to the accompanying drawings. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments; detailed descriptions will not be repeated below.

[0099] Reference Figure 3 As shown, Figure 3 This application illustrates a method for manufacturing a back-contact photovoltaic cell, which includes:

[0100] Step S1, a battery cell body 100 is provided, the battery cell body 100 having a first surface 110 and a second surface opposite to each other.

[0101] In step S2, a main grid 200 and a connector 400 are formed on the first surface 110. The main grid 200 extends along the second direction, and a plurality of main grids 200 are arranged at intervals along the first direction. The second direction and the first direction intersect. Some connectors 400 are connected to the main grid 200, and some connectors 400 are spaced apart in the second direction.

[0102] Step S3: A fine grid 300 is formed on the first surface 110 to obtain a back-contact photovoltaic cell. The fine grid 300 extends discontinuously along a first direction, and several fine grids 300 are arranged at intervals along a second direction; wherein, the fine grids 300 are interrupted at the position of the line where the main grid 200 is located, and the interrupted fine grids 300 are connected by connectors 400.

[0103] Furthermore, the process of forming the main grid 200 and the connector 400 includes a screen printing process.

[0104] In some embodiments, the connector 400 and the main grid 200 are integrally formed. The integrally formed connector 400 and the main grid 200 can make their surfaces flat, thereby improving the adhesion between the surface of the main grid 200 and the solder strip, improving the welding connection between the back contact photovoltaic cell and the solder strip, improving the stability of the welding structure of the two welded connections, and avoiding the problems of broken welding and incomplete welding between the solder strip and the welding part 500.

[0105] Accordingly, another embodiment of this application also provides a stacked battery, which includes a back-contact photovoltaic cell and a thin-film battery stacked on one side of the back-contact photovoltaic cell. The back-contact photovoltaic cell serves as the bottom cell in the stacked battery, and the thin-film battery serves as the top cell in the stacked battery. The back-contact photovoltaic cell is the back-contact photovoltaic cell provided in the above embodiment. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments, which will not be elaborated upon below.

[0106] In some embodiments, the thin-film battery includes at least one of a perovskite thin-film battery, a gallium arsenide thin-film battery, a cadmium telluride thin-film battery, and a copper indium gallium selenide thin-film battery.

[0107] Accordingly, another embodiment of this disclosure also provides a photovoltaic module, which includes a cell string, solder ribbons, encapsulating film, and a cover plate. The cell string is formed by connecting a plurality of back-contact photovoltaic cells or stacked cells, wherein the back-contact photovoltaic cells are as described in the above embodiments or obtained by the manufacturing method of the back-contact photovoltaic cells described in the above embodiments, and the stacked cells are as described in the above embodiments; solder ribbons connect adjacent back-contact photovoltaic cells; the encapsulating film covers the surface of the back-contact photovoltaic cells; and the cover plate is located on the surface of the encapsulating film away from the back-contact photovoltaic cells. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments, which will not be elaborated upon below.

[0108] The encapsulating film can be made of organic encapsulating films such as ethylene-vinyl acetate copolymer film, polyvinyl octene co-elastomer film, or polyvinyl butyral film.

[0109] The cover plate can be a glass cover plate, a plastic cover plate, or other cover plate with light transmission function. In some embodiments, the surface of the cover plate facing the adhesive film can be an uneven surface, thereby increasing the utilization rate of incident light.

[0110] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A back-contact photovoltaic cell, characterized in that, include: A battery cell body (100) having opposing first surfaces (110) and second surfaces; A main gate (200), a plurality of main gates (200) are disposed on the first surface (110), the main gates (200) extend along a second direction, and the plurality of main gates (200) are arranged sequentially at intervals along a first direction; the second direction intersects the first direction; A plurality of fine grids (300) are disposed on the first surface (110), the fine grids (300) extend along the first direction, and the fine grids (300) are interrupted at the straight line position of the main grid (200); A connector (400) is provided on the first surface (110), and the connector (400) is provided on the straight line where the main grid (200) is located; the connector (400) is provided collinearly with the fine grid (300) and connects to the fine grid (300) at the position where the fine grid (300) is disconnected; The connector (400) includes a first connector (410) and a second connector (420); the first connector (410) includes a first connector body (411) extending along the first direction, and the first connector body (411) intersects and connects with the main gate (200); the second connector (420) includes a second connector body (421) extending along the first direction, and the second connector body (421) is correspondingly spaced from the main gate (200) in the second direction; the length of the first connector body (411) is a first length L1, and the length of the second connector body (421) is a second length L2, satisfying that 3≤L2 / L1≤8.

2. The back-contact photovoltaic cell according to claim 1, characterized in that, The connector (400) includes: A connector body (401) extends along a first direction; Overlapping portions (402) are provided at both ends of the connector body (401); the overlapping portions (402) are symmetrically arranged with the straight line of the connector body (401) as the center line; The fine grid (300) is connected to the overlapping portion (402).

3. The back-contact photovoltaic cell according to claim 2, characterized in that, The overlapping portion (402) extends along the second direction.

4. The back-contact photovoltaic cell according to claim 3, characterized in that, In the first direction, the width of the overlapping portion (402) is a first width W1; in the second direction, the width of the fine grid (300) is the fine grid width N1, satisfying that 0.8≤W1 / N1≤1.

2.

5. The back-contact photovoltaic cell according to claim 4, characterized in that, The first width W1 of the overlapping portion (402) satisfies that 10μm≤W1≤100μm.

6. The back-contact photovoltaic cell according to claim 2, characterized in that, In the second direction, the width of the fine grid (300) is the fine grid width N1, and the width of the connector body (401) is the second width W2, satisfying that 1≤N1 / W2≤2.

5.

7. The back-contact photovoltaic cell according to claim 3, characterized in that, The first surface (110) includes a first region (111) and a second region (112) alternately arranged along the second direction, the first region (111) and the second region (112) extending discontinuously along the first direction; the fine gates (300) with different polarities are respectively arranged in the first region (111) and the second region (112); In the second direction, the width of the first region (111) is the width of the first region D1, the width of the second region (112) is the width of the second region D2, and the length of the overlapping part (402) is the overlapping length L3, satisfying 0.2≤L3 / D1≤1 and 0.2≤L3 / D2≤1.

8. The back-contact photovoltaic cell according to claim 7, characterized in that, The overlap length L3 of the overlap portion (402) satisfies 50μm≤L3≤560μm.

9. The back-contact photovoltaic cell according to claim 2, characterized in that, In the first direction, the width of the main gate (200) is the main gate width N2; in the second direction, the width of the connector body (401) is the second width W2, satisfying 0.8≤N2 / W2≤1.

2.

10. The back-contact photovoltaic cell according to claim 9, characterized in that, The second width W2 of the connector body (401) satisfies 10μm≤W2≤560μm.

11. The back-contact photovoltaic cell according to claim 1, characterized in that, The first connector (410) further includes: a first overlapping portion (412) disposed at both ends of the first connector body (411) and extending along the second direction; the first connector body (411) intersects and connects with the main grid (200); The second connector (420) further includes: a second overlapping portion (422) disposed at both ends of the second connector body (421) and extending along the second direction; the second connector body (421) is disposed at intervals corresponding to the main gate (200) in the second direction; The fine grid (300) connected by the second connector (420) has a different polarity from the main grid (200) that is spaced apart from it.

12. The back-contact photovoltaic cell according to claim 11, characterized in that, 200μm≤L1≤600μm, 200μm≤L2≤1200μm.

13. The back-contact photovoltaic cell according to claim 1, characterized in that, The main gate (200) and the connecting part (400) it connects to are an integral structure.

14. A method for manufacturing a back-contact photovoltaic cell, characterized in that, The back-contact photovoltaic cell as described in any one of claims 1 to 13 is manufactured by the method for manufacturing the back-contact photovoltaic cell; The manufacturing method of the back contact photovoltaic cell includes: A battery cell body (100) is provided, the battery cell body (100) having opposing first surfaces (110) and second surfaces; A main grid (200) and a connector (400) are formed on the first surface (110). The main grid (200) extends along a second direction, and a plurality of the main grids (200) are arranged at intervals along a first direction. The second direction intersects the first direction. Some of the connectors (400) are connected to the main grids (200), and some of the connectors (400) are spaced apart in the second direction. Fine grids (300) are formed on the first surface (110) to obtain a back-contact photovoltaic cell; the fine grids (300) extend discontinuously along the first direction, and a plurality of the fine grids (300) are arranged at intervals along the second direction; wherein, the fine grids (300) are broken at the position of the line where the main grid (200) is located, and the broken fine grids (300) are connected by the connector (400).

15. A stacked battery, characterized in that, include: The back contact photovoltaic cell is the back contact photovoltaic cell as described in any one of claims 1 to 13, or the back contact photovoltaic cell is manufactured by the manufacturing method of the back contact photovoltaic cell as described in claim 14; A thin-film battery, wherein the thin-film battery is disposed on the side of the back contact photovoltaic cell.

16. A photovoltaic module, characterized in that, include: A battery string, wherein the battery string is composed of a plurality of back-contact photovoltaic cells or stacked cells connected together, wherein the back-contact photovoltaic cell is a back-contact photovoltaic cell as described in any one of claims 1 to 13, or the back-contact photovoltaic cell is manufactured by the manufacturing method of the back-contact photovoltaic cell as described in claim 14, and the stacked cell is a stacked cell as described in claim 15. Solder strips, which connect adjacent back-contact photovoltaic cells or stacked cells; An encapsulating film that covers the surface of the back contact photovoltaic cell; A cover plate located on the surface of the encapsulating film away from the back contact photovoltaic cell.

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