Back-contact solar cells and photovoltaic modules

Abstract

To provide a back contact solar cell capable of avoiding short circuit due to contact of electrodes of a different polarity and preventing invalidation of a cell.SOLUTION: A back contact solar cell includes a substrate, a conductive layer, and an electrode structure. A plurality of conductive layers are arranged along a first direction. Adjacent conductive layers have an opposite conductive polarity and are installed electrically insulated. The electrode structure includes gate electrodes and gate lines intersecting with and electrically connected to the gate electrode. The gate electrodes having an opposite conductive polarity are arranged at intervals along a second direction intersecting with the first direction. The gate lines having an opposite conductive polarity are arranged at intervals along the first direction. The gate lines are located on the conductive layer having the same conductive polarity. The gate electrode and the gate line having an opposite conductive polarity have an intersection. The gate line at the intersection is disconnected and separated from the gate electrode in the second direction. The disconnected gate line is electrically connected through the conductive layer having the same conductive polarity. An insulating layer is provided between the gate electrode and the conductive layer at the intersection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application is in the field of solar cells, and in particular back-contact solar cells and photovoltaic modules. [Background technology]

[0002] Solar cells are devices that convert light energy into electrical energy, and as a sustainable, clean energy source, they have great prospects for development. Unlike conventional double-sided electrode contact solar cells, back-contact cells have metal electrodes installed on the backlight side of the cell, leaving the light-receiving side of the cell unobstructed, resulting in higher light utilization, higher short-circuit current, and higher conversion efficiency.

[0003] However, in back-contact batteries, the positive and negative electrodes are all installed on the back, and the two polarity electrode structures are distributed alternately, which makes it easy for short circuits to occur due to contact between the positive and negative electrodes, resulting in the battery failing. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application aims to solve at least one of the technical problems existing in the prior art by proposing a back-contact solar cell and a photovoltaic module that can avoid the occurrence of a short circuit phenomenon caused by contact between electrodes of different polarities and prevent the cell from failing. [Means for solving the problem]

[0005] According to a first aspect, the present application proposes a back contact solar cell, the back contact solar cell comprising: a substrate, a conductive layer, and an electrode structure; the conductive layer is provided on one surface of the substrate, a plurality of the conductive layers are arranged along a first direction, and adjacent conductive layers have opposite conductive polarities and are electrically insulated from each other; the electrode structure is provided on a surface of the conductive layer away from the substrate, the electrode structure includes a gate electrode and a gate line intersecting the gate electrode and electrically connected thereto, the gate electrodes having opposite conductive polarities are arranged at intervals along a second direction intersecting the first direction, the gate lines having opposite conductive polarities are arranged at intervals along the first direction, and the gate lines are located on the conductive layer having the same conductive polarity; The gate electrode and the gate line, which have opposite conductive polarities, have an intersection, the gate line at the intersection is broken and separated from the gate electrode in the second direction, the broken gate line is electrically connected via the conductive layer, which has the same conductive polarity, and an insulating layer is provided between the gate electrode and the conductive layer at the intersection.

[0006] In the back-contact solar cell of the present application, the gate line is disconnected at the intersection of the gate electrode and the gate line, which have opposite conductive polarities, and an insulating layer is provided to separate the gate line from the gate electrode, and the disconnected gate line is electrically connected via the conductive layer, thereby avoiding the occurrence of a short circuit due to contact between electrodes of different polarities, preventing battery failure, reducing consumption of raw materials for manufacturing electrodes, and reducing battery manufacturing costs.

[0007] According to one embodiment of the present application, at the intersection, the width of the insulating layer in the second direction is equal to or greater than the width of the gate electrode in the second direction.

[0008] According to one embodiment of the present application, at the intersection, the distance over which the gate line is broken is greater than the width of the gate electrode in the second direction.

[0009] According to one embodiment of the present application, at the intersection, the width of the insulating layer in the second direction is equal to or greater than the distance of the disconnection of the gate line.

[0010] According to one embodiment of the present application, the square resistance of the conductive layer is 20 ohm / sq to 1000 ohm / sq.

[0011] According to one embodiment of the present application, a connection layer is further installed at the intersection adjacent to the conductive layer, the square resistance of the connection layer is smaller than the square resistance of the conductive layer, the broken gate line forms a conductive path through the connection layer, and the insulating layer separates the connection layer from the gate electrode.

[0012] According to one embodiment of the present application, a projection area of ​​the insulating layer on the substrate is equal to or larger than a projection area of ​​the connecting layer on the substrate.

[0013] According to one embodiment of the present application, at the intersection, the width of the connection layer in the second direction is equal to or greater than the distance of the disconnection of the gate line.

[0014] According to one embodiment of the present application, the back contact solar cell has the connection layer and the conductive layer disposed at the intersection on opposite sides along the second direction.

[0015] According to one embodiment of the present application, the back contact solar cell has the conductive layer or the connection layer and the conductive layer at the intersection of the intermediate portion in the second direction.

[0016] According to one embodiment of the present application, the connection layer comprises a conductive metal. According to one embodiment of the present application, the conductive metal is silver and / or copper.

[0017] According to one embodiment of the present application, the conductive metal has a dimension of at least one of nano-order, sub-micron-order, and micron-order.

[0018] According to one embodiment of the present application, the square resistance of the connection layer is 0.001 ohm / sq to 10 ohm / sq.

[0019] According to one embodiment of the present application, the projection shape of the connection layer on the substrate is rectangular, circular, elliptical, or irregular.

[0020] According to one embodiment of the present application, the substrate includes an impurity semiconductor layer, a passivation layer, and a semiconductor substrate, which are arranged in this order along a direction away from the conductive layer.

[0021] According to a second aspect, the present application proposes a photovoltaic module, the photovoltaic module comprising: The back contact solar cell comprises the back contact solar cell according to the first aspect.

[0022] According to the photovoltaic module of the present application, the back-contact solar cell of the photovoltaic module has a gate line that is disconnected at the intersection of the gate electrode and gate line, which have opposite conductive polarities, and an insulating layer that separates the gate line from the gate electrode, and the disconnected gate line is electrically connected via the conductive layer, thereby avoiding the occurrence of a short circuit due to contact between electrodes of different polarities, preventing battery failure, reducing consumption of raw materials for manufacturing electrodes, and reducing battery manufacturing costs.

[0023] Additional aspects and advantages of the present application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present application.

[0024] The above and / or additional aspects and advantages of the present application will be apparent and readily understood from the following description of the embodiments in conjunction with the drawings. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a plan view of a back contact solar cell according to an embodiment of the present application. [Figure 2] 2 is a plan view 2 of a back contact solar cell according to an embodiment of the present application. [Figure 3] 1 is a schematic cross-sectional view of a back contact solar cell according to an embodiment of the present application at an intersection. [Figure 4] 2 is a cross-sectional view of a back contact solar cell according to an embodiment of the present application at an intersection point. [Figure 5]3 is a cross-sectional schematic diagram 3 of a back contact solar cell according to an embodiment of the present application at an intersection. [Figure 6] 4 is a cross-sectional schematic diagram 4 of a back contact solar cell according to an embodiment of the present application at an intersection. [Figure 7] 3 is a schematic cross-sectional view of a back contact solar cell according to an embodiment of the present application taken along a second direction. [Figure 8] FIG. 1 is a cross-sectional view of a solar cell according to a related art technique. [Figure 9] 1 is a schematic cross-sectional view of a back contact solar cell according to an embodiment of the present application taken along a first direction; DETAILED DESCRIPTION OF THE INVENTION

[0026] The following is a detailed description of the embodiments of the present application, examples of which are shown in the drawings. Here, the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are illustrative and are used only to interpret the present application, and should not be understood as limitations of the present application.

[0027] The back-contact solar cell and photovoltaic module according to the embodiments of the present application are described below by the following specific embodiments and their application scenarios in conjunction with the drawings.

[0028] As shown in FIG. 1, a back contact solar cell includes a substrate 100, a conductive layer, and an electrode structure.

[0029] The substrate 100 has one surface facing directly to the sunlight and another surface facing away from the sunlight.

[0030] In this embodiment, the conductive layer is provided on one side of the substrate 100, i.e., the side facing away from the sunlight, and the electrode structure is provided on the side of the conductive layer facing away from the substrate 100, i.e., the conductive layer is located between the substrate 100 and the electrode structure.

[0031] The electrode structure includes a gate electrode and a gate line crossing the gate electrode and electrically connected thereto, wherein the cross-sectional area of ​​the gate line can be smaller than that of the gate electrode, i.e., the gate line is thinner than the gate electrode, and the gate line crossing the gate electrode and electrically connected thereto transfers collected carriers to the gate electrode, where they are merged and output.

[0032] In actual practice, the electrode structures may be fabricated using conductive metals such as silver and / or copper.

[0033] It will be appreciated that a back contact solar cell includes two electrode structures of different conductivity polarities for transporting different carriers.

[0034] For example, as shown in FIG. 1 , a back-contact solar cell includes a first electrode structure and a second electrode structure of opposite conductive polarity, where the first electrode structure includes a first gate electrode 310 and a first gate line 311, and the second electrode structure includes a second gate electrode 320 and a second gate line 321.

[0035] The first gate line 311 crosses and is electrically connected to the first gate electrode 310, and the first gate line 311 transfers collected carriers to the first gate electrode 310. The second gate line 321 crosses and is electrically connected to the second gate electrode 320, and the second gate line 321 transfers collected carriers to the second gate electrode 320.

[0036] In this embodiment, the back contact solar cell may include two conductive layers of opposite conductive polarities, the conductive layers arranged along a first direction, and adjacent conductive layers having opposite conductive polarities and being electrically insulated.

[0037] Here, the first direction is a direction on a plane on which the substrate 100 is located. For example, a back contact solar cell may include a first conductive layer 210 and a second conductive layer 220 of opposite conductive polarities arranged at a distance from each other along a first direction from top to bottom on a substrate 100, and the conductive layers of opposite conductive polarities may be electrically insulated to prevent recombination of different carriers.

[0038] In actual implementation, the conductive layers of opposite conductive polarities are electrically isolated from each other by providing a physical gap, for example, a spaced apart opening between the first conductive layer 210 and the second conductive layer 220.

[0039] In this embodiment, gate electrodes of opposite conductive polarities are arranged at intervals along a second direction intersecting the first direction, and gate lines of opposite conductive polarities are arranged at intervals along the first direction, and the gate lines are located on conductive layers of the same conductive polarity.

[0040] Here, the second direction is a direction on the plane on which the substrate 100 is located, and the second direction intersects with the first direction.

[0041] In actual practice, the second direction and the first direction may be perpendicular to each other. As shown in FIG. 1 , the back contact solar cell may include first and second gate electrodes 310 and 320 of opposite conductive polarities arranged at intervals along a second direction from left to right on the substrate 100, and second gate lines 311 and 321 of opposite conductive polarities arranged at intervals along a first direction from top to bottom on the substrate 100.

[0042] The gate line is located on a conductive layer having the same conductive polarity, and the conductive layer collects carriers generated from the substrate 100 and transfers them to the gate line, which then transfers the collected carriers to the gate electrode.

[0043] The gate electrodes and gate lines of the electrode structure are arranged along intersecting first and second directions, respectively, and gate electrodes and gate lines with the same conductive polarity are connected crosswise, while gate electrodes and gate lines with opposite conductive polarity are insulated to prevent short-circuiting of the battery.

[0044] In this embodiment, a gate electrode and a gate line having opposite conductive polarities have an intersection, the gate line at the intersection is disconnected and separated from the gate electrode in the second direction, the disconnected gate line is electrically connected via a conductive layer having the same conductive polarity, and an insulating layer is provided between the gate electrode and the conductive layer at the intersection.

[0045] For example, as shown in FIG. 2, the second gate electrode 320 and the first gate line 311 have an intersection, and at the intersection, the first gate line 311 is disconnected and spaced apart from the second gate electrode 320 in the second direction.

[0046] The first gate electrode 310 and the second gate line 321 have an intersection, and at the intersection, the second gate line 321 is disconnected and separated from the first gate electrode 310 in the second direction, thereby avoiding contact between the gate line and the gate electrode, which have opposite conductive polarities.

[0047] Here, the insulating layer of the back contact solar cell can include a first insulating layer 410 and a second insulating layer 420, each located at a different crossing point.

[0048] For example, as shown in FIG. 3, the first gate line 311 is broken at the intersection with the second gate electrode 320, and the broken first gate line 311 is electrically connected via the first conductive layer 210, which has the same conductive polarity, and a second insulating layer 420 is provided between the second gate electrode 320 and the first conductive layer 210 to prevent contact between the second gate electrode 320 and the first conductive layer 210.

[0049] As shown in FIG. 5, the second gate line 321 is broken at the intersection with the first gate electrode 310, and the broken second gate line 321 is electrically connected via the second conductive layer 220 having the same conductive polarity, and a first insulating layer 410 is provided on the first gate electrode 310 and the second conductive layer 220 to prevent contact between the first gate electrode 310 and the second conductive layer 220.

[0050] In practical implementation, the insulating layer located between the conductive layer and the gate electrode can be made of insulating paste, insulating ink, and other materials.

[0051] In related technology, a low-temperature silver paste is printed using a screen printing method and sintered at a temperature of about 200°C to form a back-contact battery electrode. The low-temperature silver paste uses a mixture of silver powder in the form of sheets and spheres. Because the silver powder has a large size range, the shape of the final sub-gate is rough, with large height variations and many protrusions. This punctures the insulating layer between the main gate and sub-gate, which have opposite conductive polarities, resulting in an electrical connection due to contact between the main gate and sub-gate, which have opposite conductive polarities, causing a short circuit and battery failure.

[0052] Also, as shown in FIG. 8, in the related art, when the main gate S10 crosses the sub-gate S21 of opposite conductivity polarity and the sub-gate S11 of the same conductivity polarity, the height of the main gate S10 increases due to the presence of an insulating layer J1 between the main gate S10 and the sub-gate S21 of opposite conductivity polarity, but the height of the main gate S10 decreases due to contact between the main gate S10 and the sub-gate S11 of the same conductivity polarity, resulting in a height difference H2 of approximately several tens of μm between the two points of the main gate S10. This height difference not only affects battery testing and tandem welding, but also increases the consumption of silver paste, thereby increasing battery manufacturing costs.

[0053] In an embodiment of the present application, in a back-contact solar cell, a gate electrode and a gate line, which have opposite conductive polarities, cross at a point where the gate line crosses, and the gate line is disconnected and separated from the gate electrode in a second direction, thereby physically preventing contact between the gate electrode and a protrusion that may exist on the gate line, solving the problem of short circuits caused by protrusions of low-temperature silver paste, and preventing battery failure; the disconnected gate line is electrically connected via a conductive layer with the same conductive polarity, which enables carrier transmission between the two disconnected gate lines; and an insulating layer is provided between the gate electrode and the conductive layer at the crossing point, preventing short circuits caused by contact between the gate electrode and the conductive layer, which have opposite conductive polarities.

[0054] 7, in the embodiment of the present application, the first gate electrode 310 is in contact with the first gate line 311 of the same conductive polarity, and the first gate line 311 is located below the first gate electrode 310. The second gate line 321 of the opposite conductive polarity is disconnected at the intersection of the first gate electrode 310 and the second gate line 321. The first insulating layer 410 is located below the first gate electrode 310. Here, the height of the first gate electrode 310 is low, so that the height difference H1 between the two points of the first gate electrode 310 can be effectively reduced. H1 is smaller than H2, which reduces the consumption of silver paste for manufacturing the battery and reduces the manufacturing cost of the battery.

[0055] In the back contact solar cell according to the embodiment of the present application, the gate line and the gate electrode, which have opposite conductive polarities, are cut at the intersection and an insulating layer is provided to separate the gate line from the gate electrode, and the cut gate line is electrically connected via the conductive layer. This avoids the occurrence of short circuits due to contact between electrodes of different polarities, prevents battery failure, reduces consumption of raw materials for manufacturing electrodes, and reduces battery manufacturing costs.

[0056] In some embodiments, at the intersection, the width of the insulating layer in the second direction is greater than or equal to the width of the gate electrode in the second direction.

[0057] In this embodiment, an insulating layer is provided at the intersection between the gate electrode and the conductive layer, which have opposite conductive polarities, and the width of the insulating layer in the second direction is equal to or greater than the width of the gate electrode in the second direction. The insulating layer effectively prevents the gate electrode from contacting the underlying conductive layer, which has opposite conductive polarities, thereby enhancing the insulating effect of the insulating layer.

[0058] For example, as shown in FIG. 5, at the intersection, the width in the second direction of the first gate electrode 310 is D1, the width in the second direction of the first insulating layer 410 below the first gate electrode 310 is D3, and D3 can be greater than or equal to D1. The first gate electrode 310 and the second conductive layer 220 are isolated by the first insulating layer 410, and the problem of a short circuit due to contact between the first gate electrode 310 and the second conductive layer 220 below can be avoided.

[0059] In some embodiments, at the intersection, the distance the gate line is broken is greater than the width of the gate electrode in the second direction.

[0060] In this embodiment, the open distance of the gate line is the distance between both ends of the gate line at the intersection, i.e., the width of the open gate line along the second direction. The open distance of the gate line is greater than the width of the gate electrode in the second direction, which improves the spacing effect between the gate electrode and the gate line, which have opposite conductive polarities, and prevents contact between the gate electrode and the protrusion that may exist on the gate line. At the same time, the open gate line reduces the amount of silver paste used in the electrode structure and reduces the manufacturing costs of the battery.

[0061] For example, as shown in FIG. 5, at the intersection, the width of the first gate electrode 310 in the second direction is D1, and the distance along the second direction at which the second gate line 321 is broken is D2, where D2 is greater than D1, and the first gate electrode 310 and the second gate line 321 are physically spaced apart to avoid contact between the gate electrode and the gate line, which have opposite conductive polarities.

[0062] In actual implementation, the disconnection distance of the gate line can be adjusted according to the conductive performance of the underlying conductive layer, the position where the gate line is located, and so on.

[0063] For example, in the case of a conductive layer with high conductivity, the distance over which the gate line is broken can be increased, and in the case of a conductive layer with low conductivity, the distance over which the gate line is broken can be decreased.

[0064] In some embodiments, at the intersection, the width of the insulating layer in the second direction is equal to or greater than the break in the gate line.

[0065] In this embodiment, when the width of the insulating layer in the second direction is equal to the distance of the break in the gate line, both ends of the insulating layer contact the both ends of the break in the gate line, and the insulating layer fills the gap between the both ends of the break in the gate line, separating the gate electrode above the insulating layer from the conductive layer below, thereby achieving an insulating effect.

[0066] When the width of the insulating layer in the second direction is larger than the distance of the break in the gate line, the insulating layer covers both ends of the broken gate line, i.e., by covering both ends of the broken gate line with the insulating layer and separating the gate electrode above the insulating layer from the conductive layer below, and at the same time covering the broken end of the gate line, it is possible to prevent a protrusion that can be formed on the gate line from contacting the gate electrode, and to avoid a short circuit due to contact between the broken end of the gate line and the welding band when the assembly is tandem welded.

[0067] For example, as shown in FIG. 5, at the intersection, the width in the second direction of the first insulating layer 410 below the first gate electrode 310 is D3, and the distance of the disconnection of the second gate line 321 is D2, and D3 is greater than or equal to D2, which effectively prevents contact between the gate electrode and the gate line and the conductive layer and avoids the occurrence of a short circuit.

[0068] In some embodiments, at the intersection, the width of the insulating layer in the second direction is greater than the break distance of the gate line, and the break distance of the gate line is greater than the width of the gate electrode in the second direction.

[0069] For example, as shown in FIG. 5, at the intersection, the width in the second direction of the first insulating layer 410 below the first gate electrode 310 is D3, the distance of the break in the second gate line 321 is D2, and the width in the second direction of the first gate electrode 310 is D1, where D3 is greater than D2 and D2 is greater than D1.

[0070] In this embodiment, the insulating layer covers both broken ends of the gate line, the distance over which the gate line is broken is greater than the width of the gate electrode, the gate line and the gate electrode are physically spaced apart, and the insulating layer can also prevent contact between the gate electrode and a protrusion that can be formed on the gate line, thereby avoiding a short circuit due to contact between the broken end of the gate line and the welding band when the assembly is tandem welded.

[0071] In some embodiments, the conductive layer has a square resistivity of between 20 ohm / sq and 1000 ohm / sq.

[0072] Among them, square resistance, also known as sheet resistance, refers to the electrical resistance between a square of conductive material, measured in ohms per square meter (ohm / sq). The higher the square resistance, the lower the conductive performance of the conductive material.

[0073] In this embodiment, the square resistance of the conductive layer is 20 ohm / sq to 1000 ohm / sq, and the conductive layer within this square resistance range can realize electrical connection between open gate lines.

[0074] In some embodiments, the conductive layer has a square resistivity of 100 ohm / sq to 500 ohm / sq.

[0075] In this embodiment, a conductive layer with a square resistance range of 100 ohm / sq to 500 ohm / sq can provide a stable electrical connection between open gate lines.

[0076] In actual practice, the conductive layer can be made of a material such as a transparent conductive oxide. In some embodiments, a connecting layer is further provided at the intersection adjacent to the conductive layer, the square resistance of the connecting layer is smaller than the square resistance of the conductive layer, the open gate line forms a conductive path through the connecting layer, and the insulating layer separates the connecting layer from the gate electrode.

[0077] In addition, the square resistance of the connection layer is smaller than the square resistance of the conductive layer, and the conductive performance of the connection layer is superior to that of the conductive layer, and a connection layer is provided at the intersection, providing a conductive path formed by the connection layer and a conductive path formed by the conductive layer for the broken gate line.

[0078] Among them, the installation of the connection layer can increase the current collection area, reduce the square resistance of the connection layer, and prevent the open gate line from being broken through the conductive path formed by the connection layer, which can reduce the string resistance of the battery, improve the carrier transmission efficiency, reduce current loss, and effectively improve the photoelectric conversion efficiency of the battery.

[0079] In this embodiment, at the intersection of the gate electrode and the gate line, which have opposite conductive polarities, the connection layer is placed in close proximity to the conductive layer, and the insulating layer is placed between the connection layer and the gate electrode. The insulating layer separates the connection layer from the gate electrode, thereby effectively preventing the connection layer and the gate electrode from connecting to each other and causing a short circuit in the battery.

[0080] For example, as shown in FIG. 4, at the intersection of the first gate line 311 and the second gate electrode 320, a first connection layer 510 is provided adjacent to the first conductive layer 210, and the second insulating layer 420 is adjacent to the second gate electrode 320.

[0081] The broken first gate line 311 forms a conductive path through the first connecting layer 510, and the broken first gate line 311 is electrically connected to the first conductive layer 210 below the first connecting layer 510. The conductive performance of the first connecting layer 510 is superior to that of the first conductive layer 210. The provision of the first connecting layer 510 improves the stability of the electrical connection at both ends of the broken gate line 311 and improves the carrier transmission efficiency.

[0082] In this embodiment, the second insulating layer 420 separates the first connecting layer 510 and the second gate electrode 320, thereby preventing the battery from shorting out due to contact between the first connecting layer 510 and the second gate electrode 320.

[0083] In some embodiments, the square resistance of the connecting layer is between 0.001 ohm / sq and 10 ohm / sq.

[0084] In this embodiment, the connecting layer has a square resistance of 0.001 ohm / sq to 10 ohm / sq. A connecting layer with this square resistance range can form an effective conductive path between open gate lines, reduce the string resistance, improve the carrier transmission efficiency of the open gate lines, and improve the photoelectric conversion efficiency of the battery.

[0085] In actual implementation, the square resistance of the connection layer is 0.5 ohm / sq to 1.5 ohm / sq. In some embodiments, the conductive layer has a square resistance of 20 ohm / sq to 1000 ohm / sq, the connecting layer has a square resistance of 0.001 ohm / sq to 10 ohm / sq, and the connecting layer has a square resistance smaller than the conductive layer. A connecting layer is provided at the intersection, and the broken gate line has a conductive path formed by the conductive layer and a conductive path formed by the connecting layer with better conductive performance, thereby improving the photoelectric conversion efficiency of the back contact solar cell.

[0086] In some embodiments, the connecting layer comprises a conductive metal, and the open gate lines are connected to each other by the conductive metal to form a conductive path.

[0087] In some embodiments, the conductive metal is silver and / or copper. In this embodiment, the electrode structure can be made of metallic silver, and the conductive metal can be silver. By electrically connecting the same metal, the transmission loss at both ends of the disconnected gate electrode can be effectively reduced, and the photoelectric conversion efficiency of the battery can be improved.

[0088] Furthermore, by providing a connection layer containing conductive metal below the insulating layer, the dimensions of the conductive metal, etc. can be limited so that the formed connection layer does not have large protrusions and does not puncture the insulating layer.

[0089] In some embodiments, the conductive metal has dimensions in at least one of the nanometer order, submicrometer order, and micrometer order.

[0090] In this embodiment, the connecting layer can be fabricated using nano-order and / or sub-micron-order and / or micron-order metal particles such as silver, which connect the broken gate lines to each other to form a conductive path, and the connecting layer does not have large protrusions and does not puncture the insulating layer.

[0091] In actual implementation, the connection layer can be fabricated by inkjet printing nano- and / or sub-micron silver metal, and by screen printing nano- and / or sub-micron and / or micron silver metal.

[0092] In some embodiments, the projected area of ​​the insulating layer on the substrate 100 is equal to or greater than the projected area of ​​the connecting layer on the substrate 100 .

[0093] In this embodiment, the projection area of ​​the connecting layer is located within the projection area of ​​the insulating layer, and the projection area of ​​the insulating layer is equal to or greater than the projection area of ​​the connecting layer, and the insulating layer can cover the connecting layer, so that the connecting layer can form a conductive path for the broken gate line, while at the same time improving the effectiveness of the insulating setting between the gate electrode and the connecting layer and avoiding the occurrence of battery short circuit.

[0094] In actual implementation, on the substrate 100, the projected area of ​​the insulating layer is greater than or equal to the projected area of ​​the connecting layer, which can be expressed as the width of the insulating layer in the first direction being greater than or equal to the width of the connecting layer in the first direction, and the width of the insulating layer in the second direction being greater than or equal to the width of the connecting layer in the second direction.

[0095] In some embodiments, the projected shape of the connection layer on the substrate 100 is rectangular, circular, elliptical, or irregular.

[0096] In this embodiment, the rectangular, circular, elliptical, or irregular-shaped connecting layer has a wider current collection range, and both ends in the second direction of its projection on the substrate 100 are respectively connected to both ends of the open gate line, so that the connecting layer can form a conductive path between both ends of the open gate line.

[0097] The projection shape of the insulating layer on the substrate 100 may be rectangular, circular, elliptical, or irregular.

[0098] Wherein, a rectangular, circular, elliptical or irregularly shaped insulating layer can separate the gate electrode from the underlying connecting layer, conductive layer and open gate line.

[0099] It will be understood that the projected area of ​​the insulating layer on the substrate 100 is equal to or greater than the projected area of ​​the connecting layer on the substrate 100, and that the insulating layer and the connecting layer may have the same shape or different shapes.

[0100] In some embodiments, at the intersection, the width of the connecting layer in the second direction is equal to or greater than the break in the gate line.

[0101] In this embodiment, when the width of the connecting layer in the second direction is equal to the distance of the open gate line, both ends of the connecting layer contact both ends of the open gate line, connecting the open gate lines to each other and forming a conductive path, thereby reducing the amount of conductive metal used to manufacture the connecting layer and reducing the manufacturing cost of the battery.

[0102] When the width of the connection layer in the second direction is larger than the distance of the disconnection of the gate line, both ends of the connection layer cover both ends of the disconnected gate line, and the contact area between the connection layer and the gate line increases, thereby increasing the carrier collection range of the connection layer and improving the photoelectric conversion efficiency of the battery.

[0103] For example, as shown in FIG. 6, at the intersection, the width of the second connection layer 520 in the second direction is D4, and the distance over which the gate line is broken is D2. Since D4 is greater than D2, both ends of the second connection layer 520 cover both ends of the broken second gate line 321, the contact area between the second connection layer 520 and the second gate line 321 is large, the carrier collection range is wide, and the photoelectric conversion efficiency of the battery is improved.

[0104] In this embodiment, the projection area of ​​the first insulating layer 410 is larger than the projection area of ​​the second connecting layer 520, the width of the first insulating layer 410 in the second direction is D3, and the width of the second connecting layer 520 in the second direction is D4, and since D3 is larger than D4, the first insulating layer 410 can cover the second connecting layer 520, which can improve the effectiveness of the insulation setting between the gate electrode and the connecting layer and avoid the occurrence of battery short circuit.

[0105] In some embodiments, at the intersection, the width of the connecting layer in the second direction is equal to or greater than the distance the gate line is broken, and the width of the insulating layer in the second direction is equal to or greater than the width of the connecting layer in the second direction.

[0106] The intersection of the gate line and gate electrode with opposite conductive polarity in a back contact solar cell can be arranged in at least one of the following ways:

[0107] In method 1, an insulating layer is provided between the conductive layer and the gate electrode at the intersection, and the broken gate line is electrically connected via the conductive layer.

[0108] In method 2, an insulating layer and a connecting layer are provided between the conductive layer and the gate electrode at the intersection, the insulating layer is close to the gate electrode, the connecting layer is close to the conductive layer, the square resistance of the connecting layer is smaller than the square resistance of the conductive layer, a broken gate line forms a conductive path through the connecting layer, and the insulating layer separates the connecting layer from the gate electrode.

[0109] In some embodiments, the back contact solar cell has a connecting layer and a conductive layer at the crossover on opposite sides along the second direction.

[0110] Here, opposite sides along the second direction refer to the positions of the two outermost gate electrodes in the second direction in a back contact solar cell.

[0111] For example, as shown in FIG. 1, the gate electrodes of a back contact solar cell are arranged along a second direction from left to right, with adjacent gate electrodes having opposite conductivity polarities.

[0112] In this embodiment, the opposing sides along the second direction are a first gate electrode 310 located at the leftmost side of the back contact solar cell and a second gate electrode 320 located at the rightmost side of the back contact solar cell, and a connection layer and a conductive layer are provided at the intersections corresponding to the outermost first gate electrode 310 and second gate electrode 320.

[0113] Furthermore, the current collected by the gate lines at the intersection is transmitted to the adjacent gate electrode along the second direction. However, in the case of a gate line located at the outermost gate electrode, the current is transmitted to the adjacent gate electrode on one side, resulting in a large current loss due to transmission through the conductive layer, which may result in a decrease in battery efficiency. By providing a connection layer, a conductive path is formed between the broken gate lines by the connection layer with low square resistance, and the current transmission can be equivalent to when both ends of the gate lines are not broken. This reduces the current loss between the broken gate lines or prevents excess current loss, thereby improving battery efficiency.

[0114] In some embodiments, the back contact solar cell has a conductive layer disposed at the intersection of the intermediate portion in the second direction.

[0115] Here, the intermediate portion refers to the locations of the gate electrodes other than the two outermost gate electrodes distributed along the second direction in the back contact solar cell.

[0116] For example, as shown in FIG. 1, the gate electrodes of a back contact solar cell are arranged along a second direction from left to right, with adjacent gate electrodes having opposite conductivities.

[0117] In this embodiment, the intermediate portion in the second direction is the position of the gate electrodes other than the outermost first gate electrode 310 and second gate electrode 320, and includes the positions of the four intermediate gate electrodes.

[0118] A second insulating layer 420 is provided at the intersection of the second gate electrode 320 and the first gate line 311 in the middle portion, and as shown in Figure 3, the broken first gate line 311 is electrically connected via the first conductive layer 210.

[0119] A first insulating layer 410 is provided at the intersection of the first gate electrode 310 and the second gate line 321 in the middle portion, and as shown in Figure 5, the broken second gate line 321 is electrically connected via the second conductive layer 220.

[0120] In addition, the current collected by the gate line at the intersection is transmitted to the adjacent gate electrode along the second direction. In the case of a gate line located in the middle of a gate electrode, the current can be transmitted to the adjacent gate electrodes on both sides. This reduces current loss, reduces the impact on battery efficiency due to a break in the gate line, and eliminates the need for a connecting layer in the middle. This effectively reduces the battery manufacturing cost without significantly affecting battery efficiency.

[0121] In some embodiments, the back contact solar cell includes a connecting layer and a conductive layer at the intersection of the intermediate portion in the second direction.

[0122] In this embodiment, a connecting layer is provided at the intersection, and a conductive path is formed between the broken gate lines by the connecting layer with low square resistance, and the current transmission can be equivalent to when both ends of the gate lines are not broken. By providing the conductive layer and the connecting layer, the current loss can be effectively reduced and the battery efficiency can be improved.

[0123] In actual implementation, a connecting layer may be installed at the intersection corresponding to the positions of the two outermost gate electrodes of a back contact solar cell, or at the position of the gate electrode in the middle, or no connecting layer may be installed.

[0124] In addition, the electrode structure of the back-contact solar cell is located on one side of the backlight, and a heterojunction (HJT) structure is formed in the back-contact solar cell, which allows the back-contact solar cell to combine the excellent passivation effect and advantages of a heterojunction cell, such as a high open-circuit voltage. In addition, by installing a passivation structure in the back-contact solar cell, the carrier selection and passivation contact characteristics of a TOPCon cell can be combined with the back-contact solar cell, thereby increasing the photoelectric conversion efficiency of the cell.

[0125] In some embodiments, the substrate 100 includes a doped semiconductor layer, a passivation layer, and a semiconductor substrate 101, disposed in sequence in a direction away from the conductive layer.

[0126] Wherein, the impurity semiconductor layer includes doped polycrystalline silicon, doped amorphous silicon, doped nanocrystalline silicon, or doped microcrystalline silicon, and the passivation layer includes tunnel oxide or intrinsic amorphous silicon.

[0127] When the passivation layer is a tunnel oxide and the impurity semiconductor layer is doped polycrystalline silicon, a TOPCon structure can be formed. When the passivation layer is intrinsic amorphous silicon and the impurity semiconductor layer is doped amorphous and / or microcrystalline silicon, an HJT structure can be formed.

[0128] In this embodiment, the electrode structure of the back contact solar cell is located on one side of the backlight, and by installing a TOPCon structure, in which the first passivation layer 111 is a tunnel oxide and the first impurity semiconductor layer 112 is doped polycrystalline silicon, and an HJT structure, in which the second passivation layer 121 is intrinsic amorphous silicon and the second impurity semiconductor layer 122 is doped amorphous and / or microcrystalline silicon, the cell efficiency is effectively improved and the process complexity is reduced, and this back contact solar cell belongs to the hybrid back contact solar cell (Hybrid BC).

[0129] In some embodiments, the electrode structure of the back contact solar cell is located on one side of the backlight, and a heterojunction structure is established, in which the first passivation layer 111 and the second passivation layer 121 are intrinsic amorphous silicon, and the first impurity semiconductor layer 112 and the second impurity semiconductor layer 122 are doped amorphous and / or microcrystalline silicon, thereby effectively improving the cell efficiency, and the back contact solar cell belongs to a heterojunction back contact solar cell (HJT-BC).

[0130] In actual practice, when metallizing the HJT of a back contact solar cell to fabricate an electrode structure, a low temperature silver paste can be printed by screen printing and sintered at a temperature of about 200°C.

[0131] Among them, most of the silver powder used in low-temperature silver paste is a mixture of sheet-shaped and spherical silver powder. The sheet-shaped silver powder has a large size range, and due to the large particles among them, the shape of the final gate line is rough, with large height fluctuations and many protrusions.

[0132] In this embodiment, when the gate line is disconnected at the intersection of the gate electrode and the gate line, which have opposite conductive polarities, and is separated from the gate electrode in the second direction, the protrusions that may be present on the gate line formed from the low-temperature silver paste can be effectively prevented from puncturing the insulating layer and coming into contact with the gate electrode, which has opposite conductive polarity, to form an electrical connection, thereby avoiding short-circuit failure of the battery.

[0133] Furthermore, if the gate line is broken at the intersection, the height difference at the intersection between the gate electrode and the gate line of a different conductive polarity can be reduced, facilitating battery testing and tandem welding. Furthermore, reducing the height difference can reduce the consumption of silver paste in the electrode structure, thereby reducing the battery manufacturing cost.

[0134] The backlight surface of the back contact solar cell is formed with two types of polar regions with opposite conductive polarities, and each type of polar region includes a passivation layer, an impurity semiconductor layer, and a conductive layer corresponding to the two types of polar regions with opposite conductive polarities. The front surface of the back contact solar cell may be provided with a third passivation layer 130 and an anti-reflection layer 140 to improve the absorption rate and conversion rate of sunlight inside the cell.

[0135] For example, as shown in FIG. 9, the backlight surface includes a first polarity region 102 and a second polarity region 103 arranged at intervals along the second direction, the first polarity region 102 includes a first passivation layer 111, a first impurity semiconductor layer 112, and a first conductive layer 210, and a first gate line 311 of a first electrode structure is provided in the first polarity region 102, the second polarity region 103 includes a second passivation layer 121, a second impurity semiconductor layer 122, and a second conductive layer 220, and a second gate line 321 of a second electrode structure is provided in the second polarity region 103.

[0136] Here, the first passivation layer 111 may include tunnel oxide or intrinsic amorphous silicon, the first impurity semiconductor layer 112 may include doped polycrystalline silicon or doped amorphous silicon (the amorphous silicon may be replaced with nanocrystalline silicon or microcrystalline silicon), the second passivation layer 121 includes intrinsic amorphous silicon, and the second impurity semiconductor layer 122 includes doped amorphous silicon (the amorphous silicon may be replaced with nanocrystalline silicon or microcrystalline silicon).

[0137] It will be understood that the two types of impurity semiconductor layers are located in different polarity regions, the doping type of the first impurity semiconductor layer 112 being the same as or opposite to the doping type of the semiconductor substrate 101, and the doping type of the second impurity semiconductor layer 122 being opposite to the doping type of the first impurity semiconductor layer 112.

[0138] As shown in FIG. 9, the first conductive layer 210 and the second conductive layer 220 are electrically insulated from each other, and the electrically insulated arrangement can be achieved by providing spaced apart openings between the first conductive layer 210 and the second conductive layer 220.

[0139] In actual implementation, the passivation layer and the impurity semiconductor layer form a layered structure that transmits carriers, and the layered structures that transmit different carriers may not overlap or may have partial overlapping regions.

[0140] It will be appreciated that regions of different polarity will carry different carriers and that overlapping regions of layers carrying different carriers may be provided with an insulating layer 150 to separate the different layers.

[0141] For example, as shown in FIG. 9, an overlap region exists between the first passivation layer 111 and the first impurity semiconductor layer 112 and the second passivation layer 121 and the second doped semiconductor layer 122, and an insulator layer 150 exists between the first passivation layer 111 and the first impurity semiconductor layer 112 and the second passivation layer 121 and the second doped semiconductor layer 122 in the overlap region.

[0142] In actual implementations, the insulator layer 150 may include at least one of phosphosilicon glass, borosilicon glass, silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxide.

[0143] An embodiment of the present application further provides a photovoltaic module. The photovoltaic module includes at least one back-contact solar cell as described above.

[0144] Here, multiple back contact solar cells can be connected in series or in parallel. According to the photovoltaic module of the embodiment of the present application, the back-contact solar cell of the photovoltaic module has a gate line that is disconnected at the intersection of the gate electrode and gate line, which have opposite conductive polarities, and an insulating layer that separates the gate line from the gate electrode, and the disconnected gate line is electrically connected via the conductive layer, thereby avoiding the occurrence of a short circuit due to contact between electrodes of different polarities, preventing battery failure, reducing the consumption of raw materials for manufacturing electrodes, and reducing battery manufacturing costs.

[0145] The terms "first," "second," etc. in this specification and claims are used to distinguish between similar objects and are not intended to describe a particular order or chronological order. It should be understood that data used in this manner may be interchanged where appropriate so that embodiments of the present application can be implemented in an order other than that illustrated or described herein. Objects distinguished by "first," "second," etc. are generally of the same type and do not limit the number of objects; for example, the first object may be one or more. Furthermore, "and / or" in this specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0146] In the description of this specification, orientations or positional relationships indicated by terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer" are orientations or positional relationships indicated based on the drawings, and are intended to facilitate and simplify the description of the present application, and do not indicate or imply that the indicated devices or elements must have a particular orientation or be constructed and operate in a particular orientation, and therefore should not be understood as limitations of the present application.

[0147] In the present description, a "first feature" or a "second feature" may include one or more features.

[0148] In this description, "plurality" means two or more. In the description of this application, a first feature being "above" or "below" a second feature can include direct contact between the first and second features, and can also include contact between the first and second features that is not direct contact but is rather contacted via another feature between them.

[0149] In this description, a first feature being "on," "above," and "on top of" a second feature includes indicating that the first feature is directly above and diagonally above the second feature, or simply that the first feature has a higher horizontal height than the second feature.

[0150] In the description herein, the use of reference terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in connection with this embodiment or example are included in at least one embodiment or example of the present application. In the description herein, general references to the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

[0151] Although the embodiments of the present application have been shown and described above, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is limited by the claims and their equivalents. [Explanation of symbols]

[0152] 100 substrate, 101 semiconductor substrate, 102 first polarity region, 103 second polarity region, 111 first passivation layer, 112 first impurity semiconductor layer, 121 second passivation layer, 122 second impurity semiconductor layer, 130 third passivation layer, 140 anti-reflection layer, 150 insulator layer, 210 first conductive layer, 220 second conductive layer, 310 first gate electrode, 311 first gate line, 320 second gate electrode, 321 second gate line, 410 first insulating layer, 420 second insulating layer, 510 first connecting layer, 520 second connecting layer.

Claims

1. a substrate, a conductive layer, and an electrode structure; the conductive layer is provided on one surface of the substrate, a plurality of the conductive layers are arranged along a first direction, and adjacent conductive layers have opposite conductive polarities and are electrically insulated from each other; the electrode structure is provided on a surface of the conductive layer away from the substrate, the electrode structure including gate electrodes and gate lines intersecting with and electrically connected to the gate electrodes, the gate electrodes having opposite conductive polarities are arranged at intervals along a second direction intersecting with the first direction, the gate lines having opposite conductive polarities are arranged at intervals along the first direction, and the gate lines are located on the conductive layer having the same conductive polarity; the gate electrode and the gate line, which have opposite conductive polarities, have an intersection, the gate line at the intersection is disconnected and separated from the gate electrode in the second direction, the disconnected gate line is electrically connected via the conductive layer, which has the same conductive polarity, and an insulating layer is provided between the gate electrode and the conductive layer at the intersection, a connecting layer is further provided at the intersection adjacent to the conductive layer, the connecting layer having a square resistance smaller than that of the conductive layer, the disconnected gate line forms a conductive path through the connecting layer, the insulating layer separates the connecting layer from the gate electrode, the width of the connecting layer in the second direction at the intersection is equal to the distance the gate line is disconnected, and the connecting layer includes the same conductive metal as the metal of the electrode structure; 1. A back contact solar cell comprising:

2. At the intersection, the width of the insulating layer in the second direction is equal to or greater than the width of the gate electrode in the second direction.

10. The back contact solar cell of claim 1.

3. At the intersection, the distance over which the gate line is broken is greater than the width of the gate electrode in the second direction.

10. The back contact solar cell of claim 1.

4. At the intersection, the width of the insulating layer in the second direction is equal to or greater than the distance of the disconnection of the gate line.

10. The back contact solar cell of claim 1.

5. The square resistance of the conductive layer is 20 ohm / sq to 1000 ohm / sq 10. The back contact solar cell of claim 1.

6. The projection area of ​​the insulating layer on the substrate is equal to or larger than the projection area of ​​the connecting layer on the substrate.

10. The back contact solar cell of claim 1.

7. The back contact solar cell has the connection layer and the conductive layer at the intersection on both sides opposite to each other along the second direction.

10. The back contact solar cell of claim 1.

8. The back contact solar cell has the conductive layer provided at the intersection of the intermediate portion in the second direction, or the connection layer and the conductive layer provided.

10. The back contact solar cell of claim 1.

9. The conductive metal is silver and / or copper.

10. The back contact solar cell of claim 1.

10. The conductive metal has a size on at least one of the nano-order, sub-micron-order, and micron-order.

10. The back contact solar cell of claim 1.

11. The square resistance of the connection layer is 0.001 ohm / sq to 10 ohm / sq 10. The back contact solar cell of claim 1.

12. The projection shape of the connection layer on the substrate is rectangular, circular, elliptical, or irregular.

10. The back contact solar cell of claim 1.

13. The substrate includes an impurity semiconductor layer, a passivation layer, and a semiconductor substrate, which are arranged in this order along a direction away from the conductive layer. A back contact solar cell according to any one of claims 1 to 5.

14. Comprising at least one back contact solar cell according to any one of claims 1 to 5 A solar power generation module characterized by:

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