Photovoltaic cell and photovoltaic module

Abstract

The embodiment of the present application relates to the field of photovoltaic cells, and provides a photovoltaic cell and a photovoltaic module, wherein the photovoltaic cell comprises: a cell body having opposite second edges in a second direction; main grids extending along the second direction and being arranged at intervals along a first direction; a plurality of welding portions being arranged at intervals along the first direction and the second direction, and the welding portions being electrically connected with the main grids; the welding portion comprising a first welding point and a second welding point; the first welding point being arranged at a position close to the second edge, and the second welding point being arranged between a pair of first welding points opposite in the second direction; and at least part of a first insulating portion being arranged between the corresponding first welding point and the second edge, and the first insulating portion being in contact with the first welding point. The embodiment of the present application can at least solve the problem of broken grid lines connected with the first welding point.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cells, and in particular to a photovoltaic 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 grid lines, thus facilitating the efficient use of electrical energy. The grid lines of a PV cell play a crucial role in collecting and transporting electrons. When assembling multiple PV cells into a PV module, solder pads and / or solder joints are often placed on the grid lines. Subsequently, solder ribbons are used to electrically connect the grid lines of adjacent PV cells to these solder joints.

[0003] To further avoid shading of the front side of photovoltaic cells by the grid lines, research on IBC cells (Interdigitated Back Contact) cells, also known as back contact cells, is becoming increasingly in-depth. Typically, the starting or ending solder joints are spaced apart from the edge of the cell to prevent warping or cracking of the cell edge caused by thermal stress from the welding of the starting or ending solder joints to the solder strip. A fine grid is also installed between the starting or ending solder joints and the cell edge to collect charge carriers.

[0004] In related technologies, insulating adhesive is applied to the surface of the fine grid between the starting or ending solder joint and the edge of the cell. This serves two purposes: firstly, it prevents the solder strip from coming into contact with the fine grid of different polarities, thus avoiding short circuits; secondly, it prevents the fine grid from melting and breaking during the welding process after the solder strip comes into contact with the fine grid.

[0005] However, in addition to the fine grid, there are also grid lines (such as main grids) connected to the starting or ending solder joints and the edge of the cell between the starting or ending solder joints and the cell edge. The insulating adhesive is usually spaced apart from the starting or ending solder joints, which causes the grid lines (fine grids or main grids) to be exposed through the gap between the insulating adhesive and the starting or ending solder joints. The exposed grid lines still have the risk of grid breakage during the soldering process.

[0006] Therefore, it is necessary to find a solution to the above-mentioned problem of broken grid lines. Utility Model Content

[0007] This application provides a photovoltaic cell and a photovoltaic module, which at least helps to solve the problem of broken grid lines connected to the first solder joint.

[0008] According to some embodiments of this application, one aspect of this application provides a photovoltaic cell, comprising: a cell body having intersecting first and second directions, the cell body having opposing second edges in the second direction; a main grid extending along the second direction, a plurality of main grids being spaced apart along the first direction; a welding portion having a plurality of welding portions spaced apart along the first and second directions, the welding portions being electrically connected to the main grids; the welding portion including a first solder joint and a second solder joint; the first solder joint being disposed near the second edge, the second solder joint being disposed between a pair of opposing first solder joints in the second direction; and a first insulating portion, at least a portion of the first insulating portion being disposed between a corresponding first solder joint and the second edge, the first insulating portion being in contact with the first solder joint.

[0009] In some embodiments, the system further includes: a fine grid extending along the first direction, and a plurality of the fine grids spaced apart along the second direction; the fine grids being disconnected at locations of the main grids or the welded portions having a polarity different from their own, and the fine grids being in contact with the main grids having a polarity similar to their own; at least a portion of the fine grids being disposed between corresponding first weld points and second edges; and the first insulating portion covering at least a portion of the fine grids.

[0010] In some embodiments, the first insulating portion covers a portion of the first solder joint.

[0011] In some embodiments, in the first direction, the ratio between the width of the first insulating portion and the width of the first solder joint is 1.3 to 3.

[0012] In some embodiments, in the first direction, the width of the first insulating portion is 0.3 mm to 5 mm, and the width of the first solder joint is 0.5 mm to 2 mm.

[0013] In some embodiments, in the second direction, the overlap dimension of the first insulating portion and the first solder joint is the overlap dimension D1, and the length of the first solder joint is the solder joint length L2, satisfying that 0 < W1 / W2 ≤ 0.3.

[0014] In some embodiments, 0μm≤D1≤200μm, 300μm≤L2≤1500μm.

[0015] In some embodiments, the main gate includes an intermediate main gate, which is coaxially disposed with a portion of the first solder joint, the intermediate main gate extending between the first solder joint and the second edge, and the first insulating portion covering the portion of the intermediate main gate disposed between the first solder joint and the second edge.

[0016] In some embodiments, a second insulating portion is further included; the axis on which the plurality of weld portions spaced apart in a second direction is located is a first axis, and the second insulating portion is disposed on both sides of the first axis and at least covers the fine grid with a polarity different from that of the weld portions corresponding to the first axis.

[0017] In some embodiments, the second insulating portion extends along the first direction, and a plurality of the second insulating portions are spaced apart along the second direction.

[0018] In some embodiments, the second insulating portion disposed between adjacent first axes extends at least to the centerline position between adjacent first axes.

[0019] In some embodiments, the dimension of the second insulating portion in the second direction gradually decreases in a direction away from the first axis.

[0020] In some embodiments, in the first direction, the distance between adjacent first axes is the axial distance L, and the length of the second insulating portion is the third length L3, wherein L3 ≤ 0.8 × L.

[0021] In some embodiments, 0.5mm≤L3≤6mm, 1mm≤L≤15mm.

[0022] In some embodiments, the second insulating portion extends along the second direction at the first axial position, and the second insulating portion has a window penetrating the second insulating portion, through which the solder joint or the main gate is exposed.

[0023] In some embodiments, in the first direction, the width of the second insulating portion is less than or equal to the distance between adjacent first axes.

[0024] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a battery string formed by connecting a plurality of photovoltaic cells; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string; wherein the photovoltaic cells are obtained by the photovoltaic cell preparation method described above, or are photovoltaic cells as described above.

[0025] The technical solution provided in this application has at least the following advantages:

[0026] In this embodiment of the photovoltaic cell, the first insulating part and the first solder joint located at the edge of the cell body are connected in contact to avoid gaps between the insulating adhesive and the first solder joint, thereby preventing the grid lines from being exposed through the gaps. As a result, during the welding process with the solder strip, the grid lines that are not exposed through the gaps are prevented from melting and breaking due to welding heat or from breaking due to mechanical force when in contact with the solder strip, thus improving the reliability of the photovoltaic cell. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a schematic diagram of the structure of the photovoltaic cell provided in Embodiment 1 of this application;

[0029] Figure 2 This is a schematic diagram of the structure of a photovoltaic cell with the first insulating part removed, as provided in Embodiment 1 of this application;

[0030] Figure 3 This is a schematic diagram of a portion of the structure of the photovoltaic cell provided in Embodiment 1 of this application;

[0031] Figure 4 This is a schematic diagram of a portion of the structure of the photovoltaic cell provided in Embodiment 2 of this application;

[0032] Figure 5 This is a schematic diagram of a portion of the photovoltaic cell structure proposed in Embodiment 3 of this application;

[0033] Figure 6 This is a schematic diagram of a portion of the photovoltaic cell structure proposed in Embodiment 4 of this application;

[0034] Figure 7 This is a schematic diagram of a portion of the structure of the photovoltaic cell proposed in Embodiment 5 of this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100. Cell body; 101. First edge; 102. Second edge; 210. Main grid; 211. Edge main grid; 212. Middle main grid; 220. Fine grid; 230. Auxiliary line; 240. First connecting line; 250. Second connecting line; 300. Welding part; 310. First solder joint; 320. Second solder joint; 410. First insulating part; 420. Second insulating part. Detailed Implementation

[0037] As is known from the background art, in related technologies, the insulating adhesive set between the starting point or the end point of the solder joint and the edge of the cell has a gap with the starting point or the end point of the solder joint. Some of the grid lines (such as the main grid) connecting the starting point or the end point of the solder joint are exposed through the gap. During the process of welding the solder strip to the solder joint, the grid lines exposed through the gap are at risk of grid breakage.

[0038] This application provides a photovoltaic cell in which an insulating adhesive is provided between a first solder joint and a second edge of the cell body. The insulating adhesive covers not only the fine grid between the corresponding first solder joint and the second edge, but also at least a portion of the first solder joint, to ensure that there is no gap between the insulating adhesive and the first solder joint. This avoids any grid line connected to the first solder joint from being exposed through the gap, which could lead to the risk of grid breakage during the soldering process.

[0039] 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 and 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 (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[0040] 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.

[0041] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0042] 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 orientation 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 (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0043] 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.

[0044] 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 (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Figures 1 to 2 These are schematic diagrams of the photovoltaic cell provided in Embodiment 1 of this application and schematic diagrams of the photovoltaic cell with the first insulating part 410 removed.

[0049] refer to Figures 1 to 2 Photovoltaic cells include:

[0050] The battery cell body 100 has an intersecting first direction X and a second direction Y, and the battery cell body 100 has opposing second edges 102 in the second direction Y.

[0051] Main gate 210, the main gate 210 extends along the second direction Y, and a plurality of main gates 210 are arranged at intervals along the first direction X;

[0052] Welding section 300, a plurality of welding sections 300 are spaced apart along a first direction X and a second direction Y, and the welding section 300 is electrically connected to the main grid 210; the welding section 300 includes a first weld point 310 and a second weld point 320; the first weld point 310 is located near the second edge 102, and the second weld point 320 is located between a pair of opposite first weld points 310 in the second direction Y.

[0053] A first insulating portion 410, at least a portion of which is disposed between a corresponding first solder joint 310 and a second edge 102, is in contact with the first solder joint 310.

[0054] In this embodiment of the photovoltaic cell, the first insulating part 410 and the first solder joint 310 located at the edge of the cell body 100 are connected in contact to avoid gaps between the insulating adhesive and the first solder joint 310, thereby preventing the grid lines from being exposed through the gaps. As a result, during the welding process with the solder strip, the grid lines that are not exposed through the gaps are prevented from melting and breaking due to welding heat or from breaking due to mechanical force when in contact with the solder strip, thus improving the reliability of the photovoltaic cell.

[0055] Furthermore, the first insulating part 410 partially covers the first solder joint 310, providing sufficient size and space for the welding connection between the first solder joint 310 and the solder strip.

[0056] It should be noted that the first solder point 310 in the embodiments of this application is either the starting solder point or the ending solder point in the photovoltaic cell. That is, a number of welding parts 300 are arranged sequentially at intervals along the second direction Y on the same straight line. The first solder point 310 is the first welding part 300 or the last welding part 300 on the straight line, and the remaining welding parts 300 on the straight line are the second solder points 320.

[0057] It should be noted that the first solder point 310 is located close to the second edge 102, meaning that the first solder point 310 is closer to the second edge 102 than the second solder point 320. The distance between the first solder point 310 and the second edge 102 is not specifically limited here.

[0058] It should be noted that the corresponding first solder point 310 and the second edge 102 are the first solder point 310 and the second edge 102 that is closest to it, and the corresponding position between the first solder point 310 and the second edge 102 is the position between the first solder point 310 and the edge of the battery cell body 100.

[0059] It should be noted that the first insulating portion 410 and the first solder joint 310 are in contact connection, that is, there is no gap between the first insulating portion 410 and the first solder joint 310, which prevents the grid lines from being exposed through the gap between them. The contact connection between the first insulating portion 410 and the first solder joint 310 can be that the first insulating portion 410 and the first solder joint 310 abut against each other in the second direction Y, or it can be that the first solder joint 310 is covered by the first insulating portion 410; no specific limitation is made here.

[0060] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0061] Reference Figures 1-3 As shown, Figure 3 A schematic diagram of a portion of the structure of the photovoltaic cell provided in Embodiment 1 of this application is shown, wherein... Figure 3 The first insulating portion 410 has a transparent structure. The photovoltaic cell includes a cell body 100 and grid lines, a welding portion 300, and an insulating portion disposed on the cell body 100. The cell body 100 is a semiconductor structure with photoelectric effect, capable of converting light energy into electrical energy. After receiving incident light, the internal electric field of the cell body 100 can promote the directional migration of electrons and holes. The grid lines are used to collect and transport charge carriers. The welding portion 300 is electrically connected to the grid lines for welding connection with the solder strip and transporting charge carriers to the solder strip.

[0062] In some embodiments, the photovoltaic cell is a back-contact photovoltaic cell, which 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.

[0063] In some embodiments, the photovoltaic cell type 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.

[0064] 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.

[0065] 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.

[0066] It should be noted that a photovoltaic cell can be a single-sided cell, where one surface can be considered the front of the photovoltaic cell and the other surface is the light-receiving surface for receiving incident light; or, the final photovoltaic cell can be a bi-sided cell, in which case both surfaces can be used as light-receiving surfaces to receive incident light. It is understood that the backlighting 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 backlighting surface.

[0067] Combination Figures 1-3 As shown, the solar cell body 100 has intersecting first direction X and second direction Y. In the first direction X, the solar cell body 100 has opposing first edges 101; in the second direction Y, the solar cell body 100 has opposing second edges 102. Since the positive and negative electrodes of the photovoltaic cell in this embodiment are both disposed on the back surface of the solar cell body 100, the polarity of the grid lines can be either positive or negative. The grid lines include a main grid 210, a fine grid 220, and auxiliary lines 230.

[0068] The main gate 210 extends along the second direction Y, and the main gates 210 with different electrical properties are arranged alternately and at intervals along the first direction X. The main gate 210 includes a pair of edge main gates 211 disposed near the first edges 101 on both sides, and an intermediate main gate 212 disposed between a set of edge main gates 211.

[0069] A plurality of welded portions 300 are arranged sequentially at intervals along the first direction X and the second direction Y, that is, a plurality of welded portions 300 are arranged in an array on the surface of the cell body 100. Some welded portions 300 are electrically connected to the intermediate main grid 212, and these welded portions 300 are coaxially arranged with the intermediate main grid 212 and in contact with the intermediate main grid 212; some welded portions 300 are electrically connected to the edge main grid 211, and these welded portions 300 are spaced apart from the edge main grid 211 in the first direction X, and these welded portions 300 are electrically connected to the edge main grid 211 through an auxiliary line 230 extending along the first direction X. The welding portion 300, electrically connected to the edge main grid 211, is spaced apart from the edge main grid 211 in the first direction X. This means the welding portion 300 is spaced apart from the first edge 101, preventing the welding portion 300 from being too close to the first edge 101. This avoids the first edge 101 of the cell body 100 from experiencing edge warping or cracking due to the thermal stress from the welding portion 300's connection to the solder strip, thus improving the reliability of the photovoltaic cell. The welding portion 300 includes a first solder joint 310 and a second solder joint 320. Several welding portions 300 are arranged sequentially at intervals along the second direction Y. The pair of welding portions 300 closest to the second edge 102 of the cell body 100 are the first solder joints 310, and the welding portions 300 located between the pair of first solder joints 310 are the second solder joints 320. In other words, the first solder joint 310 is either the starting point or the ending point of the welding portion 300 welded to the same solder strip. In other words, the first weld point 310 is the first or last weld point 300 of a plurality of welded portions 300 arranged coaxially along the second direction Y. The first weld point 310 is spaced apart from its corresponding second edge 102 along the second direction Y to avoid the first weld point 310 being too close to the second edge 102, which could cause warping or cracking of the second edge 102 of the battery cell body 100 due to thermal stress from the welding connection between the first weld point 310 and the solder strip.

[0070] Fine grids 220 extend along a first direction X, and fine grids 220 with different electrical polarities are alternately arranged at intervals along a second direction Y. Fine grids 220 with the same polarity are in contact with the main grid 210 or the welding part 300, while fine grids 220 are disconnected at positions where they have different polarities from the main grid 210 or the welding part 300, to avoid short circuits caused by contact between the fine grids 220 and the main grids 210 or the welding part 300. At least a portion of the fine grids 220 are disposed between the first welding point 310 and the second edge 102 to increase the coverage of the fine grids 220 on the surface of the cell body 100, improve the collection and transport efficiency of charge carriers, and thus improve the photoelectric conversion efficiency of the photovoltaic cell.

[0071] The grid lines also include a first connecting line 240 and a second connecting line 250 extending along the second direction Y. Specifically, a portion of the fine grid 220 near the first edge 101 is disposed between the edge main grid 211 and the welding portion 300, which have a different polarity. One end of the first connecting line 240 extending along the second direction Y contacts and connects with the fine grid 220, which can normally contact and connect with the main grid 210. The other end passes through the gap between the fine grid 220 (with a different polarity) and the edge main grid 211, and contacts and connects with the fine grid 220 disposed between the edge main grid 211 and the welding portion 300, which have a different polarity. One end of the second connecting line 250 contacts and connects with the welding portion 300 near the first edge 101. After passing through the gap between the fine grid 220 (with a different polarity) and the first connecting line 240, the other end contacts and connects with the fine grid 220 sandwiched between the central main grid 210 (with a different polarity) and the first connecting line 240, which have a different polarity. The arrangement of the first connecting line 240 and the second connecting line 250 is to improve the coverage of the fine grid 220 on the surface of the cell body 100, improve the collection and transport efficiency of charge carriers, and thus improve the photoelectric conversion efficiency of the photovoltaic cell.

[0072] In some embodiments, the insulating portion includes a first insulating portion 410, which is disposed on the side of the first solder joint 310 facing the second edge 102. The first insulating portion 410 at least covers the fine grid 220 between the first solder joint 310 and its corresponding second edge 102, as well as at least a portion of the first solder joint 310. The first insulating portion 410 covers the fine grid 220 between the first solder joint 310 and the second edge 102 to prevent short circuits caused by contact between the solder strip and the fine grid 220 with different polarities, and also to prevent the fine grid 220 from melting and breaking during the soldering process after the solder strip comes into contact with it. The first insulating portion 410 covers at least a portion of the first solder joint 310. On the one hand, it exposes at least a portion of the first solder joint 310 to ensure the welding connection between the first solder joint 310 and the solder strip. On the other hand, it ensures that there is no gap between the first solder joint 310 and the first insulating portion 410, thus preventing the grid line from being exposed through the gap between the first solder joint 310 and the first insulating portion 410. This would prevent the exposed grid line from melting and breaking during the solder strip welding process after it comes into contact with the solder strip.

[0073] A portion of the first solder joint 310 is coaxially arranged with the intermediate main gate 212, meaning the intermediate main gate 212 extends along the second direction Y through the first solder joint 310 to a position near the second edge 102. This intermediate main gate 212 is in contact with the fine gate 220 of the same polarity to improve the collection and transport efficiency of charge carriers. The first insulating portion 410 covers the portion of the intermediate main gate 212 facing the second edge 102 of the first solder joint 310 to prevent the portion of the intermediate main gate 212 from being exposed between the first insulating portion 410 and the first solder joint 310. During the soldering process between the first solder joint 310 and the solder strip, excessive diffusion (i.e., tin absorbing silver) occurs between the solder paste used for soldering and the silver-containing intermediate main gate 212, which can lead to gate breakage of the intermediate main gate 212. The first insulating portion 410 covering the portion of the intermediate main gate 212 facing the second edge 102 of the first solder joint 310 improves the yield and reliability of the photovoltaic cells in this embodiment.

[0074] In some embodiments, in the first direction X, the width of the first insulating portion 410 is a first width W1, and the width of the first solder joint 310 is a solder joint width W2, satisfying 1.3 ≤ W1 / W2 ≤ 3. Optionally, the first width W1 of the first insulating portion 410 and the solder joint width W2 of the first solder joint 310 satisfy 1.5 ≤ W1 / W2 ≤ 2.5, and the ratio W1 / W2 between the first width W1 of the first insulating portion 410 and the solder joint width W2 of the first solder joint 310 can be 1.7, 1.9, 2, 2.2, or 2.4. The width of the first insulating portion 410 is greater than the width of the first solder joint 310 to prevent either from shifting during the formation process, which could expose part of the first solder joint 310 near the second edge 102 (i.e., not contacting or connecting with the second edge 102). This would expose part of the grid lines at the location where the first solder joint 310 is not in contact with the first insulating portion 410, increasing the risk of grid line melting and breaking during the connection between the first solder joint 310 and the solder strip. When the ratio W1 / W2 between the first width W1 of the first insulating portion 410 and the solder joint width W2 of the first solder joint 310 is large, the first insulating portion 410 can cover a larger area of ​​grid lines (such as fine grids), further improving the protection effect of the first insulating portion 410 on the grid lines between the first solder joint 310 and the second edge 102, thereby improving the yield and reliability of the photovoltaic cells in this embodiment.

[0075] In some embodiments, in the first direction X, the first width W1 of the first insulating portion 410 satisfies 0.3mm ≤ W1 ≤ 5mm. Optionally, the first width W1 of the first insulating portion 410 satisfies 0.5mm ≤ W1 ≤ 4.5mm, and the first width W1 of the first insulating portion 410 can be 1mm, 2mm, 3mm, or 4mm. Setting the first insulating portion 410 to a suitable width ensures that, on the one hand, the first insulating portion 410 can fully contact the edge of the first solder joint 310 in the first direction X, ensuring that no grid lines are exposed at the edge of the first solder joint 310; on the other hand, it ensures the protective effect of the first insulating portion 410 on the grid lines between the first solder joint 310 and the second edge 102, thereby improving the yield and reliability of the photovoltaic cells in this application embodiment.

[0076] In some embodiments, in the first direction X, the solder joint width W2 of the first solder joint 310 satisfies 0.5mm ≤ W2 ≤ 2mm. Optionally, the solder joint width W2 of the first solder joint 310 satisfies 0.8mm ≤ W2 ≤ 1.8mm, and the solder joint width W2 of the first solder joint 310 can be 1mm, 1.2mm, 1.4mm, or 1.6mm. Setting the first solder joint 310 to an appropriate width ensures the connection effect between the first solder joint 310 and the solder strip, as well as the carrier transport efficiency between the first solder joint 310 and the solder strip to which it is welded.

[0077] In some embodiments, in the second direction Y, the size of the overlapping portion of the first insulating part 410 and the first solder joint 310 is the overlap size D1, and the length of the first solder joint 310 is the solder joint length L2, satisfying that 0 < D1 / L2 ≤ 0.3. Optionally, the ratio D1 / L2 between the overlap size D1 of the overlapping portion of the first insulating part 410 and the first solder joint 310 and the solder joint length L2 of the first solder joint 310 satisfies that 0.05 ≤ D1 / L2 ≤ 0.25, and the ratio D1 / L2 between the overlap size D1 of the overlapping portion of the first insulating part 410 and the first solder joint 310 and the solder joint length L2 of the first solder joint 310 can be 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, or 0.22. In the second direction Y, the first insulating part 410 and the first solder joint 310 are partially overlapped. On the one hand, this ensures the contact connection between the first insulating part 410 and the first solder joint 310, and avoids the possibility that either of them will be offset in the second direction Y due to process tolerances or other factors, which would prevent the first insulating part 410 and the first solder joint 310 from making contact connection, and expose the grid line in the gap between them, so that the grid line is at risk of melting and breaking during the welding process. On the other hand, it ensures that most of the first solder joint 310 is still exposed, and avoids the arrangement of the first insulating part 410 affecting the welding connection between the first solder joint 310 and the solder joint.

[0078] In some embodiments, in the second direction Y, the overlap dimension D1 of the overlapping portion of the first insulating portion 410 and the first solder joint 310 satisfies 0μm≤D1≤200μm. Optionally, the overlap dimension D1 of the overlapping portion of the first insulating portion 410 and the first solder joint 310 satisfies 20μm≤D1≤180μm, and the overlap dimension D1 of the overlapping portion of the first insulating portion 410 and the first solder joint 310 can be 40μm, 60μm, 80μm, 100μm, 120μm, 140μm, or 160μm. Setting the overlapping portion to a suitable overlap dimension ensures contact connection between the first insulating portion 410 and the first solder joint 310, and the exposure of most of the first solder joint 310 ensures the welding connection effect between the first solder joint 310 and the solder strip.

[0079] In some embodiments, in the second direction Y, the solder joint length L2 of the first solder joint 310 satisfies 300μm≤L2≤1500μm. Optionally, the solder joint length L2 of the first solder joint 310 satisfies 400μm≤L2≤1100μm, and the solder joint length L2 of the first solder joint 310 can be 500μm, 600μm, 800μm, or 1000μm. Setting the solder joint length L2 of the solder joint to a suitable size ensures that the first solder joint 310 has sufficient area to overlap with the first insulating portion 410, and also ensures the welding connection effect between the first solder joint 310 and the solder strip.

[0080] Reference Figure 4 As shown, Figure 4 The diagram shows a partial structure of a photovoltaic cell provided in Embodiment 2 of this application. In this embodiment, the insulating part further includes a second insulating part 420. A plurality of welding parts 300 are arranged sequentially at intervals along the second direction Y. The axis where the plurality of welding parts 300 are located is the first axis 301. The second insulating part is provided on both sides of the first axis 301 and is at least partially a fine grid 220 with a polarity different from that of the welding parts 300 corresponding to the first axis 301.

[0081] In some embodiments, the second insulating portion 420 is an elongated structure extending along a first direction X, and a plurality of second insulating portions 420 are sequentially spaced along a second direction Y. The second insulating portion 420 located on the side of the first solder joint 310 facing its corresponding second edge 102 is in contact with the first insulating portion 410. It should be noted that the first insulating portion 410 and the second insulating portion 420 in contact can be an integral structure or a separate structure, i.e., the first insulating portion 410 and the second insulating portion 420 are formed in batches, with at least a portion of the first insulating portion 410 in contact with at least a portion of the second insulating portion 420; no specific limitation is made here. The second insulating portion 420 covers the adjacent solder portion 300 or the fine grid 220 with a different polarity than the main grid 210, to prevent the fine grids 220 with different polarities from being electrically connected due to the offset of the solder strip, thus preventing short circuits and improving the reliability of the photovoltaic cell.

[0082] In some embodiments, the second extension disposed between adjacent first axes 301 extends at least to the centerline position between adjacent first axes 301, such that the second insulating portions 420 covering different polarities are adjacent to each other or staggered sequentially in the first direction X. That is, in the first direction X, the distance between adjacent first axes 301 is the axial distance L, and the length of the second insulating portion 420 is a third length L3, wherein L ≥ L3 ≥ 0.5 × L. The second insulating portions 420 covering different polarities being adjacent to each other or staggered in the first direction X further improves the insulation effect of the second insulating portions 420, thereby improving the reliability of the photovoltaic cell.

[0083] In some embodiments, the third length L3 of the second insulating portion 420 and the axial distance L between adjacent first axes 301 satisfy 0.5mm≤L3≤6mm and 1mm≤L≤15mm.

[0084] Reference Figure 5 As shown, Figure 5A schematic diagram of a portion of the photovoltaic cell structure proposed in Embodiment 3 of this application is shown. Compared to Embodiment 2, the structure of the second insulating portion 420 in Embodiment 3 is a gradient structure. The size of the second insulating portion 420 in the second direction Y gradually decreases along a square shape away from its corresponding first axis 301. That is, the width of the second insulating portion 420 at one end near its corresponding first axis 301 is greater than the width of the other end. The end with a larger width near the first axis 301 gives the second insulating portion 420 a better insulation effect near the main grid 210 or the welding portion 300. In the direction away from the main grid 210 or the welding portion 300, the short-circuit risk is also reduced due to the fine grid 220 it covers. Therefore, without significantly reducing the overall insulation effect of the second insulating portion 420, the size of the second welding portion 300 gradually decreases along the direction of the main grid 210 or the welding portion 300. Compared to the elongated second insulating portion 420 in Embodiment 2, the gradient structure of the second insulating portion 420 reduces the size of its planar shape while ensuring its insulation effect as much as possible, thereby reducing the amount of material required to form the second insulating portion 420 and reducing the production cost of photovoltaic cells.

[0085] In some embodiments, the planar shape of the second welded portion 300 includes at least one of the following: a triangle, a trapezoid, an arc-shaped triangle (i.e., a triangle whose long side of at least one side is arc-shaped), or an arc-side trapezoid (i.e., a trapezoid whose waistline of at least one side is arc-shaped).

[0086] Reference Figure 6 As shown, Figure 6 A schematic diagram of a partial structure of the photovoltaic cell proposed in Embodiment 4 of this application is shown. Compared to Embodiment 2, the size of the second insulating portion 420 in Embodiment 4 in the first direction X is smaller than that of the second insulating portion 420 in Embodiment 1. The second insulating portion 420 at least covers the end of the fine grid 220, which has a different polarity than the main grid 210 or the welding portion 300, to prevent the solder ribbon of different polarity from contacting and connecting with the fine grid 220 due to the offset of the solder ribbon setting, thereby causing a short circuit. The smaller size of the second insulating portion 420 can achieve a certain balance between improving the reliability of the photovoltaic cell and reducing the production cost of the photovoltaic cell, thereby improving the cost-effectiveness of the photovoltaic cell in the embodiments of this application.

[0087] In some embodiments, the second insulating portion 420 disposed between adjacent first axes 301 is spaced apart from the center line between adjacent first axes 301, and the second insulating portion 420 extends along the first direction X but does not cross the center line between adjacent axes. That is, in the first direction X, the axial distance L between adjacent first axes 301 and the third length L3 of the second insulating portion 420 satisfy L3 ≤ 0.8 × L.

[0088] In some embodiments, the third length L3 of the second insulating portion 420 satisfies 0.5mm≤L3≤6mm.

[0089] Reference Figure 7 As shown, Figure 7 A schematic diagram of a portion of the photovoltaic cell structure proposed in Embodiment 5 of this application is shown. In Embodiment 5, the insulating portion further includes a second insulating portion 420, which is an elongated structure extending along a second direction Y. The line containing the second insulating portion 420 is coaxial with the first axis 301 of the welding portion 300, which is coaxially arranged in the second direction Y. The second insulating portion 420 has a window that penetrates through the second insulating portion 420 in the thickness direction, so that the welding portion 300 or the main grid 210 corresponding to the second insulating portion 420 is exposed through the window. That is, the second insulating portion 420 is an integral structure that covers the irregular fine grid 220 adjacent to the welding portion 300 or the main grid 210, avoiding short circuits caused by contact between the solder ribbon and the irregular fine grid 220 due to solder ribbon misalignment, thereby improving the reliability of the photovoltaic cell in this embodiment. Furthermore, the second insulating portion 420 corresponding to a first axis 301 is an integral structure, which has the characteristics of simple structure and low production process requirements, thereby reducing production costs.

[0090] In some embodiments, in the first direction X, the width of the second insulating portion 420 is less than or equal to the distance between adjacent first axes 301.

[0091] It should be noted that the second insulating part 420 in this embodiment can be an integral structure with the first insulating part 410, or it can be a separate structure formed in steps with the first insulating part 410. At least part of the second insulating part 420 is in contact with the first insulating part 410. This contact connection can be overlapping or edge abutting, and no specific limitation is made here.

[0092] According to some embodiments of this application, another aspect of this application also provides a photovoltaic module for converting received light energy into electrical energy. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be described again here.

[0093] The photovoltaic module includes: a cell string, which is formed by connecting multiple photovoltaic cells formed by the preparation method of the solar cells provided in the foregoing embodiments, or formed by connecting multiple photovoltaic cells provided in the foregoing embodiments; an encapsulating film for covering the surface of the cell string; and a cover plate for covering the surface of the encapsulating film facing away from the cell string. The solar cells are electrically connected in a single piece or in multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel.

[0094] The encapsulating film can be made of organic encapsulating films such as ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyvinyl butyral (PVB) film.

[0095] 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.

[0096] 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 photovoltaic cell, characterized in that, include: A battery cell body having intersecting first and second directions, wherein the battery cell body has opposing second edges in the second direction; A main grid, the main grid extending along the second direction, and a plurality of the main grids being arranged at intervals along the first direction; A welding section, wherein a plurality of welding sections are spaced apart along the first direction and the second direction, and the welding section is electrically connected to the main gate; the welding section includes a first solder joint and a second solder joint; the first solder joint is located near the second edge, and the second solder joint is located between a pair of first solder joints opposite each other in the second direction; A first insulating portion, at least a portion of which is disposed between the corresponding first solder joint and the second edge, wherein the first insulating portion is in contact with the first solder joint.

2. The photovoltaic cell according to claim 1, characterized in that, Also includes: A fine grid, wherein the fine grid extends along the first direction, and a plurality of the fine grids are arranged at intervals along the second direction; The fine grid is disconnected at the location of the main grid or the welded part with a different polarity, and the fine grid is in contact with the main grid with the same polarity; at least a portion of the fine grid is disposed between the corresponding first weld point and the second edge; The first insulating portion covers at least a portion of the fine grid.

3. The photovoltaic cell according to claim 1, characterized in that, The first insulating portion covers part of the first solder joint.

4. The photovoltaic cell according to claim 1 or 3, characterized in that, In the first direction, the ratio between the width of the first insulating portion and the width of the first solder joint is 1.3 to 3.

5. The photovoltaic cell according to claim 4, characterized in that, In the first direction, the width of the first insulating part is 0.3mm to 5mm, and the width of the first solder joint is 0.5mm to 2mm.

6. The photovoltaic cell according to claim 3, characterized in that, In the second direction, the overlap dimension of the first insulating part and the first solder joint is the overlap dimension D1, and the length of the first solder joint is the solder joint length L2, satisfying that 0 < W1 / W2 ≤ 0.

3.

7. The photovoltaic cell according to claim 6, characterized in that, 0μm≤D1≤200μm, 300μm≤L2≤1500μm.

8. The photovoltaic cell according to claim 1, characterized in that, The main grid includes an intermediate main grid, which is coaxially disposed with a portion of the first solder joint. The intermediate main grid extends between the first solder joint and the second edge, and the first insulating portion covers the portion of the intermediate main grid disposed between the first solder joint and the second edge.

9. The photovoltaic cell according to claim 2, characterized in that, It also includes a second insulating portion; the axis on which the plurality of weld portions spaced apart in the second direction are located is the first axis, and the second insulating portion is disposed on both sides of the first axis and at least covers the fine grid with a polarity different from that of the weld portions corresponding to the first axis.

10. The photovoltaic cell according to claim 9, characterized in that, The second insulating portion extends along the first direction, and a plurality of the second insulating portions are spaced apart along the second direction.

11. The photovoltaic cell according to claim 10, characterized in that, The second insulating portion disposed between adjacent first axes extends at least to the centerline position between adjacent first axes.

12. The photovoltaic cell according to claim 10, characterized in that, The dimension of the second insulating portion in the second direction gradually decreases in the direction away from the first axis.

13. The photovoltaic cell according to claim 10, characterized in that, In the first direction, the distance between adjacent first axes is the axial distance L, and the length of the second insulating part is the third length L3, wherein L3 ≤ 0.8 × L.

14. The photovoltaic cell according to claim 13, characterized in that, 0.5mm≤L3≤6mm, 1mm≤L≤15mm.

15. The photovoltaic cell according to claim 9, characterized in that, The second insulating portion extends along the second direction at the first axis position, and the second insulating portion has a window penetrating the second insulating portion, through which the solder joint or the main grid is exposed.

16. The photovoltaic cell according to claim 9, characterized in that, In the first direction, the width of the second insulating portion is less than or equal to the distance between adjacent first axes.

17. A photovoltaic module, characterized in that, A battery string, consisting of multiple photovoltaic cells connected as described in any one of claims 1 to 16; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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