Back contact cell and photovoltaic module

Abstract

The present application discloses a back-contact cell and photovoltaic module. The back-contact cell includes a cell body, including a first surface and a second surface arranged opposite to each other; a plurality of first fine grids and a plurality of second fine grids arranged on the first surface; the first fine grids and the second fine grids extend along the first direction and are alternately spaced in sequence along the second direction; the first direction intersects the second direction; a plurality of first insulating blocks are spaced along the second direction and respectively cover the second fine grids; along the second direction, the distance between the edges of adjacent first insulating blocks is D1, and D1 ≥ 80 μm. The distance between two adjacent first insulating blocks along the second direction is large enough, so that a safe distance for the slurry to flow is reserved, thereby avoiding the situation where the slurry forming the first insulating block flows and covers the first fine grid, ensuring the stability of the electrical connection between the first fine grid and the first conductive member, and thus improving the stability of the back-contact cell performance.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a back-contact cell and a photovoltaic module. Background Art

[0002] Solar cells are the core components of photovoltaic modules, converting solar energy into electricity. Back-contact solar cells have both the positive and negative gridlines located on the back of the cell, preventing them from obstructing the front of the cell and improving the cell's photoelectric conversion efficiency.

[0003] In the prior art, when using solder strips or main grids to connect with fine grids, an insulating block needs to be set between the solder strips or main grids and the fine grids with opposite polarities. However, the insulating block often flows to cover the fine grids with the same polarity during the printing process, causing the electrical connection between the solder strips or main grids and the fine grids with the same polarity to fail, thereby affecting the performance of the back-contact battery. Summary of the Invention

[0004] The purpose of this application is to provide a back-contact cell and photovoltaic module to avoid the flow of insulating blocks during the printing process, which may lead to failure of the electrical connection between conductive parts and fine grids with the same polarity, thereby improving the stability of the back-contact cell performance.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A back-contact battery comprising:

[0007] The battery body comprises a first surface and a second surface arranged opposite to each other;

[0008] A plurality of first fine grids and a plurality of second fine grids are arranged on the first surface; the first fine grids and the second fine grids extend along the first direction and are alternately arranged along the second direction; the first direction intersects the second direction;

[0009] The plurality of first insulating blocks are spaced apart and arranged along the second direction, and respectively cover the plurality of second fine grids; along the second direction, the distance between the edges of adjacent first insulating blocks is D1, and D1 is ≥80 μm.

[0010] During the printing process of the first insulating block, the slurry may flow and cover the first fine grid, causing the electrical connection between the first conductive member and the first fine grid to fail. In view of this, the distance between the edges of adjacent first insulating blocks along the second direction is D1, and D1 ≥ 80μm. With this technical solution, the distance between two adjacent first insulating blocks along the second direction is sufficiently large, thus reserving a safe distance for slurry flow. This prevents the slurry forming the first insulating block from flowing and covering the first fine grid, ensuring the stability of the electrical connection between the first fine grid and the first conductive member, and thereby improving the stability of the back-contact battery performance.

[0011] In one implementation, the thickness of the first insulating block along the thickness of the battery body is h1, with a range of 20 μm ≤ h1 ≤ 100 μm. This ensures good isolation between the second fine grid and the first conductive member while preventing the slurry forming the first insulating block from climbing over and covering the first fine grid, thereby ensuring reliable electrical connection between the first fine grid and the first conductive member and avoiding waste of raw materials for the first insulating block.

[0012] In one implementation, along the thickness direction of the battery body, the thickness of the first insulating block is h1, the thickness of the first fine grid is h2, and h1 / h2 ≤ 4. This configuration ensures that the side surfaces of the first fine grid can block the slurry forming the first insulating block, preventing the slurry forming the first insulating block from climbing to cover the upper surface of the first fine grid, further ensuring the reliability of the electrical connection between the first fine grid and the first conductive member.

[0013] In one implementation, the back-contact battery further includes a first conductive member extending along the second direction and electrically connected to the first fine grid, so as to collect current collected by the plurality of first fine grids through the first conductive member and transmit the collected current to an external circuit.

[0014] In one implementation, the intersection of the first conductive member and the first fine grid includes a side protrusion that protrudes along the first direction. This configuration increases the contact area between the first conductive member and the first fine grid, thereby reducing the transmission resistance between the first conductive member and the first fine grid, reducing current loss, and improving the photoelectric conversion efficiency of the back-contact cell.

[0015] In one implementation, a depression is formed where the top of the side protrusion intersects the first fine grid. Specifically, along the first direction, the width of the intersection of the side protrusion and the first fine grid is appropriately reduced, thereby further saving raw materials of the first conductive member while ensuring reduced transmission resistance.

[0016] In one implementation, the back-contact cell further includes a plurality of second insulating blocks spaced apart along the second direction and respectively covering the plurality of first fine grids. Along the second direction, the distance between the edges of adjacent second insulating blocks is D2, where D2 ≥ 80 μm and / or D2 ≥ D1. This technical solution allows for a sufficient distance between two adjacent second insulating blocks along the second direction, thus preserving a safe distance for slurry flow. This prevents the slurry forming the second insulating blocks from flowing over the second fine grids, ensuring the stability of the electrical connection between the second fine grids and the second conductive member, and thereby improving the stability of the back-contact cell performance.

[0017] In one implementation, the back-contact cell further includes multiple second insulating blocks spaced apart along the second direction and respectively covering the multiple first fine grids. Along the second direction, the second insulating blocks have a width S1, and the first insulating blocks have a width S2, where S2 is greater than S1; and / or S2 is 50μm-250μm greater than S1. This arrangement reduces the amount of insulating material (e.g., insulating glue) in the second insulating blocks while ensuring adequate insulation between the first and second current collection layers.

[0018] In one implementation, the first surface has first and second regions alternately arranged along a second direction. The first and second regions extend along the first direction, with first fine gates disposed in the first regions and second fine gates disposed in the second regions. The second regions are recessed relative to the first regions toward the second surface. This prevents the second fine gates in the recessed structures from being covered by the second insulating block (or by the diffusion band), which could lead to poor contact.

[0019] In one implementation, the distance between the edges of adjacent second insulating blocks along the second direction is D2, where D2>D1, and / or D2≥120μm. This technical solution allows for a sufficiently large distance between two adjacent second insulating blocks along the second direction, thus preserving a safe distance for slurry flow. This prevents the slurry forming the second insulating blocks from flowing over the second fine grids, ensuring the stability of the electrical connection between the second fine grids and the second conductive member, and thereby improving the stability of the back-contact cell performance.

[0020] In one implementation, the back-contact battery further includes a second conductive member extending along the second direction and electrically connected to the second fine grid, so as to collect current collected by the plurality of second fine grids through the second conductive member and transmit the collected current to an external circuit.

[0021] In one implementation, the battery body includes: a semiconductor substrate, a first current collection layer, and a second current collection layer, wherein the first current collection layer and the second current collection layer extend along a first direction and are alternately arranged along a second direction; a first fine grid is arranged on the first current collection layer, and a second fine grid is arranged on the second current collection layer, and the first current collection layer and the second current collection layer collect opposite types of current;

[0022] An isolation region extending along a first direction is defined between adjacent first and second current collecting layers. Along a second direction, the isolation region between adjacent first and second current collecting layers is at least partially covered by a first insulating block. This prevents bonding material from overflowing into the isolation region and connecting to the second fine grid 4 during welding between the first fine grid 6 and the first conductive member 1, potentially causing a short circuit. This helps improve the reliability of back-contact cells.

[0023] In one implementation, along the second direction, the width of the first insulating block extending onto the adjacent first current collection layer is L1, where L1 is ≥ 40 μm. This technical solution ensures that after the first insulating block is cured, it will not affect the reliability of the electrical connection between the first fine grid and the first conductive member, thereby avoiding the occurrence of cold solder joints. Furthermore, the extension of the first insulating block onto the adjacent first current collection layer can also prevent the slurry forming the first conductive member from overflowing onto the isolation area or the second current collection layer and connecting to the second fine grid, causing a short circuit in the battery cell, thereby helping to improve the reliability of the battery string.

[0024] In one implementation, the first current collection layer and the second current collection layer are transparent conductive layers; or, the first current collection layer and the second current collection layer are doped semiconductor layers, and the doping types of the two are opposite.

[0025] In one implementation, diffusion strips are formed on both sides of the first insulating block along the second direction, and the diffusion strips include at least one material in the slurry used to form the first insulating block;

[0026] Along the second direction, the diffusion band extends from the edge of the first insulating block to the edge of the adjacent first fine grid. During the manufacturing process of the first insulating block, after the slurry is printed or laser transferred and before the slurry solidifies, one or more organic compounds in the slurry diffuse toward both sides of the first insulating block, forming diffusion bands on both sides of the first insulating block. This diffusion of the organic compounds in the slurry forming the first insulating block improves the adhesion between the first insulating block and the first surface, preventing the first insulating block from falling off.

[0027] In one implementation, the thickness of the diffusion zone along the thickness direction of the semiconductor substrate is less than the thickness of the first fine gate. With this technical solution, the thickness of the first fine gate prevents the slurry from continuing to extend and flow, further ensuring the stability of the electrical connection between the first fine gate and the first conductive member.

[0028] In one implementation, the first fine grid includes first thickened segments spaced apart along a first direction, and along a second direction, the width of the first thickened segments is greater than the width of the remaining portions of the first fine grid. By adopting this technical solution, the provision of the first thickened segments can increase the contact area between the first fine grid and the first conductive member, thereby reducing the transmission resistance between the first conductive member and the first fine grid, reducing current loss, and improving the photoelectric conversion efficiency of the back-contact battery.

[0029] And / or, the second fine grid includes second thickened segments spaced apart along the first direction, and the width of the second thickened segments along the second direction is greater than the width of the remaining portion of the second fine grid. With this technical solution, the provision of the second thickened segments can increase the contact area between the second fine grid and the second conductive member, thereby reducing the transmission resistance between the second conductive member and the second fine grid, reducing current loss, and improving the photoelectric conversion efficiency of the back-contact cell.

[0030] In one implementation, along the second direction, the distance between the edge of the second thickened segment and the adjacent second insulating block is D3, and D3 ≥ 50 μm. This arrangement reserves a safe distance for the flow of slurry, preventing the slurry flow forming the second insulating block from covering the second thickened segment, thereby ensuring the stability of the electrical connection between the second thickened segment and the second conductive member, and thereby improving the stability of the back contact battery performance.

[0031] And / or, along the second direction, the distance between the edge of the first thickened section and the adjacent first insulating block is D4, where D4 is ≥ 50 μm. This arrangement provides a safe distance for slurry flow, preventing the slurry forming the first insulating block from flowing over the first thickened section, thereby ensuring the stability of the electrical connection between the first thickened section and the first conductive member, thereby improving the stability of the back-contact battery performance.

[0032] In one implementation, the first conductive member is a main grid, and the organic matter in the slurry forming the main grid is miscible with the organic matter in the slurry forming the first insulating block. This technical solution allows the organic matter in the main grid slurry to miscible with the organic matter in the slurry forming the first insulating block, thereby strengthening the adhesion between the first conductive member and the first insulating block and further preventing the first conductive member from falling off.

[0033] A photovoltaic module includes a back-contact cell as described above; the back-contact cell also includes a first conductive member extending along the second direction and directly physically and electrically connected to the first fine grid, or electrically connected to the first fine grid through a bonding layer.

[0034] Compared with the prior art, the beneficial effects of the photovoltaic module provided by the embodiment of the present application are the same as the beneficial effects of the above-mentioned back-contact battery, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0036] Figure 1 An overall schematic diagram of a back-contact battery provided in an embodiment of the present application;

[0037] Figure 2 for Figure 1 A partial enlarged view of the middle B area;

[0038] Figure 3 for Figure 1 A partial enlarged view of area A in the middle;

[0039] Figure 4 for Figure 1 Partial cross-sectional view along CC;

[0040] Figure 5 for Figure 1 Partial cross-sectional view along the middle edge DD;

[0041] Figure 6 A schematic diagram of forming diffusion bands on both sides of a second insulating block provided in an embodiment of the present application;

[0042] Figure 7 A cross-sectional view of a diffusion zone formed on both sides of a second insulating block provided in an embodiment of the present application;

[0043] Figure 8 A schematic diagram of forming a second conductive member provided in an embodiment of the present application;

[0044] Figure 9 A partial cross-sectional view of forming a second conductive member provided in an embodiment of the present application;

[0045] Figure 10 A schematic diagram of a partially thickened second fine grid provided in an embodiment of the present application;

[0046] Figure 11 This is a schematic diagram of a first fine grid partially thickened according to an embodiment of the present application.

[0047] Reference numerals:

[0048] 1-first conductive member, 2-isolation region, 3-first insulating block, 4-second fine grid, 41-second thickened section, 5-second current collecting layer, 6-first fine grid, 61-first thickened section, 7-first current collecting layer, 8-second conductive member, 81-side raised portion, 9-second insulating block, 10-diffusion zone. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0050] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0052] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on this application.

[0053] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0054] See also Figure 1-Figure 2 The back-contact cell provided in the embodiments of the present application includes a cell body, a first fine grid 6, a second fine grid 4, and a plurality of first insulating blocks 3. The cell body includes a first surface and a second surface, which are opposed to each other along the thickness of the cell body. In the embodiments of the present application, the first surface corresponds to the backlight-repelling side of the back-contact cell, also referred to as the back surface; the second surface corresponds to the light-facing side of the back-contact cell, also referred to as the front surface.

[0055] A plurality of first fine grids 6 and a plurality of second fine grids 4 are disposed on the first surface. The first fine grids 6 and the second fine grids 4 extend along a first direction, and the plurality of first fine grids 6 and the plurality of second fine grids 4 are alternately spaced in sequence along a second direction. In some embodiments, the first surface comprises a first region, a second region, and an isolation region 2, wherein the first and second regions are alternately spaced along the second direction, and the isolation region 2 is disposed between the first and second regions. The first and second regions extend along the first direction, meaning that the lengths of the first and second regions extend along the first direction. The first and second directions intersect, meaning that the first direction is different from the second direction. The angle between the first and second directions can be acute or right. The first direction can be the length direction of the battery body or the width direction of the battery body. If the first direction is the length direction of the battery body, the second direction is the width direction of the battery body; if the first direction is the width direction of the battery body, the second direction is the length direction of the battery body. The first fine grids 6 are disposed in the first region and extend along the first direction, and the second fine grids 4 are disposed in the second region and extend along the first direction.

[0056] In addition, the plurality of first insulating blocks 3 are arranged at intervals along the second direction and respectively cover the plurality of second fine grids 4. During the printing process of forming the first insulating blocks 3, the slurry may flow to cover the first fine grids 6, causing the electrical connection between the first fine grids 6 and other components (such as the first conductive member 1) to fail. In view of the above situation, if Figure 2 As shown, the distance between the edges of adjacent first insulating blocks 3 along the second direction is D1, where D1 is ≥ 80 μm. This technical solution allows for a sufficiently large distance between two adjacent first insulating blocks 3 along the second direction, thus preserving a safe distance for slurry flow. This prevents the slurry from flowing over the first fine grids 6, ensuring the stability of the electrical connection between the first fine grids 6 and other components, thereby improving the stability of the back-contact cell performance.

[0057] Illustratively, D1 may be 80 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, 155 μm, 160 μm, or 165 μm, etc.

[0058] Theoretically, the larger the distance between two adjacent first insulating blocks 3 along the second direction, the better. However, since the width of the current collection layer cannot be too wide, the maximum distance between two adjacent first insulating blocks 3 along the second direction cannot be greater than 1000 μm.

[0059] In some embodiments, the battery body includes a semiconductor substrate, a first current collecting layer 7, and a second current collecting layer 5. Opposing surfaces along the thickness of the semiconductor substrate correspond to the first and second surfaces, respectively. The first current collecting layer 7 and the second current collecting layer 5 extend along a first direction and are alternately arranged along a second direction. The first current collecting layer 7 is formed at least in the first region. Specifically, the first current collecting layer 7 can be formed only in the first region, or the first current collecting layer 7 is formed in the first region and the isolation region 2. The second current collecting layer 5 is formed at least in the second region. Specifically, the second current collecting layer 5 can be formed only in the second region, or the second current collecting layer 5 is formed in the second region and the isolation region 2. When the first current collecting layer 7 is formed in the first region and the isolation region 2, and the second current collecting layer 5 is formed in the second region and the isolation region 2, the first current collecting layer 7 and the second current collecting layer 5 overlap in the isolation region 2. The first current collecting layer 7 and the second current collecting layer 5 collect opposite types of current, respectively collecting and conducting electrons and holes, facilitating the formation of photocurrent.

[0060] The first fine grid 6 is provided on the first current collection layer 7 and extends along the first direction, that is, the first fine grid 6 is conductively connected to the first current collection layer 7 to conduct the carriers collected by the first current collection layer 7. The second fine grid 4 is provided on the second current collection layer 5 and extends along the first direction, that is, the second fine grid 4 is conductively connected to the second current collection layer 5 to conduct the carriers collected by the second current collection layer 5. An isolation region 2 extending along the first direction is provided between the adjacent first current collection layer 7 and the second current collection layer 5 to prevent leakage. In this technical solution, along the second direction, the isolation region 2 between the adjacent first current collection layer 7 and the second current collection layer 5 is at least partially covered by the first insulating block, so that during the welding process between the first fine grid 6 and the first conductive member 1, the bonding material can be prevented from overflowing into the isolation region and connecting to the second fine grid 4, causing a short circuit, thereby helping to improve the reliability of the back-contact battery.

[0061] In other embodiments, the back contact cell further comprises a first conductive member 1, which extends along the second direction and is electrically connected to the plurality of first fine grids 6, so as to collect the current collected by the plurality of first fine grids 6 through the first conductive member 1 and transmit the collected current to an external circuit. A first insulating block 3 is provided at the intersection of the first conductive member 1 and the second fine grid 4, so as to block the second fine grid 4 from the first conductive member 1 through the first insulating block 3, thereby preventing a short circuit between the second fine grid 4 and the first conductive member 1 and affecting the photoelectric conversion efficiency of the cell. Figure 2As shown, the distance between the edges of adjacent first insulating blocks 3 along the second direction is D1, where D1 is ≥ 80 μm. This technical solution allows for a sufficiently large distance between two adjacent first insulating blocks 3 along the second direction, thus preserving a safe distance for slurry flow. This prevents the slurry from flowing over the first fine grids 6, ensuring the stability of the electrical connection between the first fine grids 6 and the first conductive member 1, and thereby improving the stability of the back-contact cell performance.

[0062] During the process of printing and forming the first conductive member 1, the paste (eg copper) forming the first conductive member 1 easily flows through the isolation region 2 to the second current collecting layer 5, resulting in leakage. Figure 2 As shown, along the second direction, the first insulating block 3 extends to the first current collection layer 7 adjacent to it. Specifically, along the second direction, the first insulating block 3 covers the second current collection layer 5, the isolation region 2 and part of the first current collection layer 7. The adoption of this technical solution ensures that after the first insulating block 3 is cured, it will not affect the reliability of the electrical connection between the first fine grid 6 and the first conductive member 1, so as to avoid the occurrence of cold solder joints. In addition, the first insulating block 3 extends to the first current collection layer 7 adjacent to it, and it can also prevent the slurry forming the first conductive member 1 from overflowing onto the isolation region 2 or the second current collection layer 5, and connecting with the second fine grid 4, causing a short circuit in the battery cell, thereby helping to improve the reliability of the battery string.

[0063] Furthermore, along the second direction, the width of the first insulating block 3 extending to the adjacent first current collecting layer 7 is L1, and L1 is ≥ 40 μm. This configuration ensures that the slurry forming the first conductive member 1 cannot enter the isolation region 2, further improving the isolation effect of the first insulating block 3. For example, L1 can be 40 μm, 41 μm, 42 μm, 43 μm, 44 μm, 45 μm, 46 μm, 47 μm, 48 μm, 49 μm, or 50 μm, etc.

[0064] Considering that if the thickness of the first insulating block 3 is too small, a good isolation effect cannot be guaranteed; if the thickness of the first insulating block 3 is too large, a large amount of slurry is required during the formation of the first insulating block 3, which is easy to climb up to cover the first fine grid 6, resulting in failure of the electrical connection between the first fine grid 6 and the first conductive member 1. In view of the above two situations, in some embodiments, the thickness of the first insulating block 3 along the thickness direction of the battery body is h1, 20μm≤h1≤100μm. This can ensure a good isolation effect between the second fine grid 4 and the first conductive member 1, and prevent the slurry forming the first insulating block 3 from climbing up to cover the first fine grid 6, thereby ensuring the reliability of the electrical connection between the first fine grid 6 and the first conductive member 1, while also avoiding waste of raw materials for the first insulating block 3.

[0065] Illustratively, the thickness h1 of the first insulating block 3 may be 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, etc.

[0066] It can be understood that, as the height of the first fine grid 6 increases along the thickness of the battery body, the slurry forming the first insulating block 3 is less likely to rise to the upper surface of the first fine grid 6. Specifically, when the height of the first fine grid 6 is high, the first fine grid 6 acts like a dam. The side surfaces of the first fine grid 6 can block the flow of the slurry forming the first insulating block 3, preventing the slurry forming the first insulating block 3 from rising to cover the upper surface of the first fine grid 6. In view of the foregoing, in some embodiments, along the thickness of the battery body, the thickness of the first insulating block 3 is h1, and the thickness of the first fine grid 6 is h2, where h1 / h2 ≤ 4. This configuration ensures that the side surfaces of the first fine grid 6 can block the slurry forming the first insulating block 3, preventing the slurry forming the first insulating block 3 from rising to cover the upper surface of the first fine grid 6, further ensuring the reliability of the electrical connection between the first fine grid 6 and the first conductive member 1.

[0067] For example, h1 / h2 may be 4, 3.5, 3, 2.5, 2, 1.5, 1, or 0.5, etc. In addition, along the thickness direction of the battery body, the thickness h2 of the first fine grid 6 may be 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, or 30 μm, etc.

[0068] In other embodiments, the back contact battery further includes a plurality of second insulating blocks 9 arranged at intervals along the second direction and respectively covering the plurality of first fine grids 6. During the printing process of forming the second insulating blocks 9, the slurry may flow to cover the second fine grids 4, causing the electrical connection between the second fine grids 4 and other components (such as the second conductive member 8) to fail. In view of the above situation, if Figure 3 As shown, along the second direction, the distance between the edges of adjacent second insulating blocks 9 is D2, where D2 ≥ 80 μm and / or D2 ≥ D1. With this technical solution, the distance between two adjacent second insulating blocks 9 along the second direction is sufficiently large, thus reserving a safe distance for slurry flow. This prevents the slurry forming the second insulating blocks 9 from flowing over the second fine grids 4, ensuring the stability of the electrical connection between the second fine grids 4 and the second conductive member 8, and thereby improving the stability of the back-contact cell performance.

[0069] Illustratively, D2 may be 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, 155 μm, 160 μm or 165 μm, etc.

[0070] The first insulating block 3 and / or the second insulating block 9 may be in any shape such as circular, rectangular, or elliptical.

[0071] In some embodiments, the back-contact cell further includes a second conductive member 8 extending along a second direction and electrically connected to the plurality of second fine grids 4. The second conductive member 8 collects the current collected by the plurality of second fine grids 4 via the second conductive member 8 and transmits the collected current to an external circuit. A second insulating block 9 corresponding to each of the first fine grids 6 is disposed at the intersection of the second conductive member 8 and the first fine grid 6. The second insulating block 9 isolates the first fine grid 6 from the second conductive member 8, preventing a short circuit between the first fine grid 6 and the second conductive member 8, which could affect the cell's photoelectric conversion efficiency.

[0072] In one embodiment, Figure 2 As shown, along the second direction, the width of the first insulating block 3 is S2, 300μm≤S2≤800μm. This prevents the width of the first insulating block 3 from being too small, thereby failing to completely isolate the second fine grid 4 from the first conductive member 1, and also prevents the width of the first insulating block 3 from being too large, thereby wasting raw materials. For example, S2 can be 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm, or 800μm. Furthermore, along the second direction, the width of the second current collecting layer 5 is W1, 200μm≤W1≤650μm. For example, W1 can be 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, or 650μm.

[0073] Furthermore, along the second direction, the width of the isolation region 2 is W3, where 40 μm ≤ W3 ≤ 100 μm. This prevents leakage caused by a too small width of the isolation region 2, while also preventing the width of the isolation region 2 from being too large and affecting carrier collection efficiency. For example, W3 can be 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm.

[0074] In one embodiment, Figure 3As shown, along the second direction, the width of the second insulating block 9 is S1, 200μm≤S1≤650μm, to prevent the width of the second insulating block 9 from being too small and failing to completely isolate the first fine grid 6 and the second conductive member 8, while also preventing the width of the second insulating block 9 from being too large and wasting raw materials. Exemplarily, S1 can be 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, or 650μm. In addition, along the second direction, the width of the first current collecting layer 7 is W2, 200μm≤W2≤600μm, for example, W2 is 220μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, or 600μm, etc.

[0075] In some embodiments, along the second direction, the width S2 of the first insulating block 3 is greater than the width S1 of the second insulating block 9 , wherein the difference between S2 and S1 is 50 μm-250 μm, and the difference can be 50 μm, 100 μm, 150 μm, 200 μm, or 250 μm, etc. This configuration can reduce the amount of insulating material (e.g., insulating glue) in the second insulating block 9 while ensuring sufficient insulation between the first current collection layer 7 and the second current collection layer 5 .

[0076] like Figure 4 and Figure 5 As shown, in some embodiments, the second region comprises a groove structure that is recessed relative to the first region toward the second surface, i.e., the groove structure is positioned lower than the remainder of the first surface. The second current collection layer 5 is positioned within the groove structure. Specifically, the second current collection layer 5 is positioned at the bottom of the groove structure, while the first current collection layer 7 is positioned in the area of the first surface excluding the groove structure. This arrangement allows the presence of the groove structure to at least partially offset the electrode structures electrically connected to the first current collection layer 7 and the second current collection layer 5 along the thickness of the battery body, thereby helping to suppress leakage.

[0077] In the case where the second region has a groove structure, such as Figure 4As shown, during the formation of the second insulating block 9, the slurry forming the second insulating block 9 flows more easily along the M direction into the groove structure under the action of gravity. As a result, when the second region has a groove structure, the slurry forming the second insulating block 9 more easily covers the second fine gate 4. In view of the above, in this technical solution, the distance between the edges of adjacent second insulating blocks 9 along the second direction is D2, where D2>D1, or D2≥120μm. This arrangement further increases the distance between two adjacent second insulating blocks 9 along the second direction, further ensuring the stability of the electrical connection between the second fine gate 4 and the second conductive member 8. In this case, along the second direction, the width S2 of the first insulating block 3 is greater than the width S1 of the second insulating block 9, where the difference between S2 and S1 is 50-250μm. This ensures that the second fine gate 4 in the groove structure is not covered by the second insulating block 9 (or covered by the diffusion band), which could lead to poor contact.

[0078] For example, when the second region has a groove structure, D2 may be 120 μm, 150 μm, 155 μm, 160 μm, 165 μm, 170 μm, 175 μm, 180 μm, 185 μm, 190 μm, 195 μm or 200 μm, etc.

[0079] It can be understood that when the second region has a groove structure, the deeper the groove structure, the more the slurry forming the second insulating block 9 will overflow into the groove structure. Therefore, in this technical solution, the depth of the groove structure can be made less than or equal to 5μm, for example, the depth of the groove is 5μm, 4μm, 3μm, 2μm or 1μm, etc., to reduce the overflow of the slurry forming the second insulating block 9.

[0080] exist Figure 4 In the embodiment, the semiconductor substrate of the first region and the second region form a step structure. Although the isolation region 2 is shown to be above the step (outside the groove), it is understandable that the isolation region 2 may also be across the step surface or below the step (inside the groove). Figure 7 As shown, when the current collection layer is a transparent conductive oxide material (TCO), the isolation region 2 can be on the step; for example, when the current collection layer is a doped layer, the isolation region 2 can be in the groove, and the doped layer can be a polysilicon layer, and there can also be a tunneling layer underneath.

[0081] like Figure 6As shown, in some embodiments, diffusion bands 10 are formed on both sides of the first insulating block 3 along the second direction. Diffusion bands 10 include at least one material within the slurry used to form the first insulating block 3. That is, during the manufacturing process of the first insulating block 3, after the slurry is printed or laser transferred and before the slurry is cured, one or more organic substances in the slurry diffuse toward both sides of the first insulating block 3, forming diffusion bands 10 on both sides of the first insulating block 3. The diffusion of the organic substances within the slurry forming the first insulating block 3 toward both sides can improve the adhesion between the first insulating block 3 and the first surface, preventing the first insulating block 3 from falling off.

[0082] Furthermore, the organic diffusion strip 10 can reduce the height difference between the diffusion strip 10 and the first insulating block 3, thereby reducing the amount of printing paste used for the busbar (first conductive element 1); or, in the absence of a busbar, reducing the amount of bonding material used at the junction between the soldering ribbon and the gate line. In this embodiment, the diffusion strip 10 is at least one organic material such as epoxy resin, photocuring agent, or photoinitiator, which is used in the insulating block material. The inorganic filler content should be less than 20% by weight to ensure that the organic material within the first insulating block 3 can spread and extend to the sides of the first fine grid 6. By controlling the spacing between the two first insulating blocks 3 to be greater than or equal to 80μm, the diffusion strip 10 has a certain height and does not overlap the first fine grid 6.

[0083] Further, such as Figure 7 As shown, along the second direction, the diffusion band 10 extends from the edge of the first insulating block 3 to the edge of the adjacent first fine grid 6. Specifically, along the second direction, the slurry used to form the first insulating block 3 gradually flows to contact the side of the first fine grid 6 before solidification. The side of the first fine grid 6 blocks the slurry from further extension and flow, thereby ensuring the stability of the electrical connection between the first fine grid 6 and the first conductive member 1.

[0084] In some embodiments, the first insulating block 3 and / or the second insulating block 9 may be made of UV-curable adhesive to ensure the formation of a diffusion band 10 of suitable thickness. Furthermore, the first conductive member 1 and / or the second conductive member 8 may be made of a base metal slurry, such as copper slurry. The first fine grid 6 and the second fine grid 4 may be made of silver, copper, or the like.

[0085] In some embodiments, along the thickness direction of the battery body, the thickness of the diffusion band 10 is less than the thickness of the first fine grid 6. With this technical solution, the thickness of the first fine grid 6 blocks the slurry from continuing to extend and flow, further ensuring the stability of the electrical connection between the first fine grid 6 and the first conductive member 1.

[0086] In other embodiments, Figure 9As shown, diffusion bands 10 are formed on both sides of the second insulating block 9 along the second direction. Diffusion bands 10 comprise at least one material from the slurry used to form the second insulating block 9. Specifically, during the manufacturing process of the second insulating block 9, after printing or laser transfer of the slurry and before the slurry cures, one or more organic compounds in the slurry diffuse toward both sides of the second insulating block 9, forming diffusion bands 10 on both sides of the second insulating block 9. Along the second direction, the diffusion bands 10 extend from the edge of the second insulating block 9 to the edge of the adjacent second fine grid 4. With this arrangement, since the second insulating block 9 has a certain thickness, there is a certain height difference between the second conductive member 8 located where the second insulating block 9 is located and where it is not. Since the diffusion bands 10 have a certain thickness, the formation of the diffusion bands 10 reduces the height difference between the second conductive member 8 located between the first and second regions, making the cell surface smoother and facilitating subsequent packaging. This effect is similar to that of the diffusion bands 10 between the two first insulating blocks 3 and will not be further elaborated here.

[0087] like Figure 8 As shown, the intersection of the first conductive element 1 and the first fine grid 6 has a side protrusion 81 that protrudes along the first direction. That is, along the first direction, the width of the first conductive element 1 at the location where the side protrusion 81 is located is greater than the width of the remaining locations of the first conductive element 1. This configuration increases the contact area between the first conductive element 1 and the first fine grid 6, thereby reducing the transmission resistance between the first conductive element 1 and the first fine grid 6, reducing current loss, and improving the photoelectric conversion efficiency of the back-contact cell. Furthermore, in this technical solution, when diffusion strips 10 are provided on both sides of the first fine grid 6, the diffusion strips 10 can prevent the slurry forming the first conductive element 1 from flowing too far in the first direction, thereby preventing the side protrusions 81 from becoming too wide.

[0088] In some embodiments, as Figure 8 As shown, a depression is formed at the intersection of the top of the side protrusion 81 and the first fine grid 6. Specifically, along the first direction, the width of the intersection of the side protrusion 81 and the first fine grid 6 is appropriately reduced, thereby further saving the raw materials of the first conductive member 1 while ensuring the reduction of transmission resistance.

[0089] In other embodiments, Figure 10As shown, the first fine grid 6 includes first thickened segments 61 spaced apart along the first direction. Along the second direction, the width of the first thickened segments 61 is greater than the width of the remaining portion of the first fine grid 6. Specifically, the first thickened segments 61 are provided at the location where the first fine grid 6 connects to the first conductive member 1. These first thickened segments 61 can be integrally formed with the remaining portion of the first fine grid 6 or formed separately. This technical solution increases the contact area between the first fine grid 6 and the first conductive member 1, thereby reducing the transmission resistance between the first conductive member 1 and the first fine grid 6, minimizing current loss and improving the photoelectric conversion efficiency of the back-contact cell.

[0090] Further, such as Figure 10 As shown, along the second direction, the distance between the edge of the first thickened section 61 and its adjacent first insulating block 3 is D4, and D4 ≥ 50μm. This arrangement reserves a safe distance for slurry flow, preventing the slurry forming the first insulating block 3 from flowing over the first thickened section 61, ensuring the stability of the electrical connection between the first thickened section 61 and the first conductive member 1, thereby improving the stability of the back contact battery performance. Exemplary, D4 can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, or 100μm, etc.

[0091] In addition, if Figure 11 As shown, the second fine grid 4 includes second thickened segments 41 spaced apart along the first direction. Along the second direction, the width of the second thickened segments 41 is greater than the width of the rest of the second fine grid 4. Specifically, the second thickened segments 41 are provided at the location where the second fine grid 4 connects to the second conductive member 8. These second thickened segments 41 can be integrally formed with the rest of the second fine grid 4 or formed separately. This technical solution increases the contact area between the second fine grid 4 and the second conductive member 8, thereby reducing the transmission resistance between the second conductive member 8 and the second fine grid 4, minimizing current loss and improving the photoelectric conversion efficiency of the back-contact cell.

[0092] Further, such as Figure 11 As shown, along the second direction, the distance between the edge of the second thickened section 41 and its adjacent second insulating block 9 is D3, and D3 ≥ 50μm. This arrangement reserves a safe distance for slurry flow, preventing the slurry forming the second insulating block 9 from flowing over the second thickened section 41, ensuring the stability of the electrical connection between the second thickened section 41 and the second conductive member 8, thereby improving the stability of the back contact battery performance. Exemplary, D3 can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, or 100μm, etc.

[0093] In some embodiments, the first conductive member 1 is a busbar. In this case, the back-contact cell is a busbar-equipped cell, and the organic matter in the slurry forming the busbar is miscible with the organic matter in the slurry forming the first insulating block 3. With this technical solution, the miscible organic matter in the busbar slurry and the first insulating block 3 slurry strengthens the adhesion between the first conductive member 1 and the first insulating block 3, further preventing the first conductive member 1 from falling off.

[0094] Among them, the material of the semiconductor substrate can be selected from materials such as silicon (Si) or germanium (Ge) or materials such as gallium arsenide (GaAs). Obviously, in terms of conductivity type, the semiconductor substrate can be an intrinsic conductive substrate, an n-type conductive substrate or a p-type conductive substrate. Optionally, the semiconductor substrate is a p-type conductive substrate or an n-type conductive substrate. Compared with the intrinsic conductive substrate, the p-type conductive substrate or the n-type conductive substrate has better conductivity, so that the final solar cell has a lower body resistivity, thereby improving the efficiency of the solar cell.

[0095] In addition, in some embodiments, the back-contact cell further includes a first doped layer and a second doped layer, wherein the first doped layer is formed at least in the first region, and the second doped layer is formed at least in the second region. For example, the first doped layer is formed in the first region and the isolation region 2, and the second doped layer is formed in the second region and the isolation region 2, with the first doped layer and the second doped layer overlapping within the isolation region 2. For another example, the first doped layer is formed only in the first region, and the second doped layer is formed only in the second region. The first doped layer can be additionally formed on the semiconductor substrate using a deposition technique, or can be formed within the semiconductor substrate by diffusion, ion implantation, or the like.

[0096] In terms of conductivity type, the first doped layer may be an n-type doped layer, and the second doped layer may be a p-type doped layer; or, the first doped layer may be a p-type doped layer, and the second doped layer may be an n-type doped layer.

[0097] In addition, the materials of the first doped layer and the second doped layer can be silicon (Si), germanium (Ge), silicon carbide (SiCx), or gallium arsenide (GaAs). Taking the example of the first doped layer and the second doped layer being both made of silicon (Si), the first doped layer can be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The second doped layer can also be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon.

[0098] When the first doped layer is one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, and the second doped layer is one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the first doped layer is formed in the first region and the isolation region 2, and the second doped layer is formed in the second region and the isolation region 2. The first doped layer and the second doped layer are overlapped in the isolation region 2. The first current collection layer 7 is arranged on the side of the first doped layer facing away from the semiconductor substrate, and the second current collection layer 5 is arranged on the side of the second doped layer facing away from the semiconductor substrate. The first current collection layer 7 and the second current collection layer 5 are both transparent conductive layers, and the first current collection layer 7 and the second current collection layer 5 are disconnected and not in contact in the isolation region 2. The transparent conductive layer has a high electrical conductivity and can promptly conduct the collected carriers, reducing the carrier recombination rate. The transparent conductive layer can also reduce the contact resistance between the first doped layer and the second doped layer and the electrode.

[0099] With respect to the transparent conductive layer described above, the embodiments of the present invention do not specifically limit the material and thickness of the transparent conductive layer. For example, the material of the transparent conductive layer may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, indium hydroxide, titanium nitride, cadmium oxide, cuprous oxide, and fluorine-doped zinc oxide. The transparent conductive layer may be a single-layer thin film or a laminated thin film. For example, the thickness of the transparent conductive layer may be greater than or equal to 10 nm and less than or equal to 100 nm.

[0100] In addition, when both the first doped layer and the second doped layer are doped polysilicon layers, the first doped layer is formed only in the first region, and the second doped layer is formed only in the second region; alternatively, the first doped layer is formed in the first region and the isolation region 2, and the second doped layer is formed in the second region and the isolation region 2. The first doped layer and the second doped layer are overlapped in the isolation region 2, and an opening is provided in the isolation region 2 that penetrates the thickness of the first doped layer and the second doped layer to isolate the first doped layer and the second doped layer to prevent leakage. In this embodiment, the first current collection layer 7 and the second current collection layer 5 are doped semiconductor layers, and the doping types of the two are opposite. That is, the first current collection layer 7 is a first doped layer, and the second current collection layer 5 is a second doped layer.

[0101] In addition, embodiments of the present application further provide a photovoltaic module comprising the back-contact cell provided in any of the aforementioned embodiments. The back-contact cell comprises a first conductive member 1 extending along a second direction and directly physically and electrically connected to a first fine grid 6, or electrically connected to the first fine grid 6 via a bonding layer. Compared to the prior art, the photovoltaic module provided by embodiments of the present application has the same beneficial effects as those of the aforementioned back-contact cell and will not be further elaborated here.

[0102] In this photovoltaic module, the first conductive element 1 is a welding ribbon, which connects at least two back-contact cells to form a cell structure (i.e., a cell string structure). In this case, the back-contact cells are busbar-less cells, and the welding ribbon is electrically connected to the first fine grid 6 via a bonding layer. The bonding layer can be specifically solder or a conductive adhesive. Using this technical solution, the welding ribbon is directly electrically connected to the first fine grid 6, reducing shading and resistance losses. When the first conductive element is a busbar, the photovoltaic module also includes a welding ribbon, which needs to be welded to the busbar via bonding material to achieve series or parallel connection of multiple cells at the module end.

[0103] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0104] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A back contact battery, characterized in that: include: The battery body comprises a first surface and a second surface arranged opposite to each other; A plurality of first fine grids and a plurality of second fine grids are disposed on the first surface; The first fine grids and the second fine grids extend along a first direction and are alternately arranged in sequence along a second direction; the first direction intersects the second direction; the first surface has a first region and a second region alternately arranged in sequence along the second direction, the first region and the second region extend along the first direction, the first fine grids are respectively arranged in the first region, and the second fine grids are respectively arranged in the second region; the second region is a groove structure, and the groove structure is recessed relative to the first region toward the second surface; a first doping layer and a second doping layer, wherein the first doping layer is formed at least in the first region, and the second doping layer is formed at least in the second region, and the first doping layer and the second doping layer have opposite doping types; a plurality of first insulating blocks arranged at intervals along the second direction and respectively covering the plurality of second fine grids; a distance D1 between edges of adjacent first insulating blocks along the second direction, D1 ≥ 80 μm; Multiple second insulating blocks are arranged at intervals along the second direction and respectively cover multiple first fine grids; along the second direction, the width of the second insulating block is S1, and the width of the first insulating block is S2, wherein S2 is greater than S1; along the second direction, the distance between the edges of adjacent second insulating blocks is D2, D2>D1.

2. The back contact battery according to claim 1, characterized in that Along the thickness direction of the battery body, the thickness of the first insulating block is h1, 20 μm≤h1≤100 μm.

3. The back contact battery according to claim 1, characterized in that Along the thickness direction of the battery body, the thickness of the first insulating block is h1, the thickness of the first fine grid is h2, and h1 / h2≤4.

4. The back contact battery according to claim 1, characterized in that The back-contact cell further includes a first conductive member extending along the second direction and electrically connected to the first fine grid.

5. The back contact battery according to claim 4, characterized in that A side protrusion protruding along the first direction is formed at the intersection of the first conductive member and the first fine grid.

6. The back contact battery according to claim 5, characterized in that A depression is formed at the intersection of the top of the side raised portion and the first fine grid.

7. The back contact battery according to claim 4, characterized in that The first conductive member is a main grid; and the organic matter in the slurry forming the main grid is mutually soluble with the organic matter in the slurry forming the first insulating block.

8. The back contact battery according to claim 1, characterized in that Along the second direction, a distance between edges of adjacent second insulating blocks is D2, where D2 ≥ 80 μm and / or D2 ≥ D1.

9. The back contact battery according to claim 8, characterized in that The back-contact cell further includes a second conductive member extending along the second direction and electrically connected to the second fine grid.

10. The back contact battery according to claim 1, characterized in that S2 is 50μm-250μm larger than S1.

11. The back contact battery according to claim 1, characterized in that D2≥120μm.

12. The back contact battery according to claim 1, characterized in that The battery body includes: a semiconductor substrate, a first current collection layer, and a second current collection layer, wherein the first current collection layer and the second current collection layer extend along a first direction and are alternately arranged in sequence along a second direction; the first fine grid is arranged on the first current collection layer, and the second fine grid is arranged on the second current collection layer, and the first current collection layer and the second current collection layer collect opposite current types; An isolation region extending along a first direction is provided between adjacent first current collecting layers and second current collecting layers; and along the second direction, the isolation region between adjacent first current collecting layers and second current collecting layers is at least partially covered by the first insulating block.

13. The back contact battery according to claim 12, characterized in that Along the second direction, the first insulating block extends to the first current collecting layer adjacent thereto with a width L1, where L1 is ≥ 40 μm.

14. The back contact battery according to claim 12, characterized in that The first current collection layer and the second current collection layer are transparent conductive layers; or the first current collection layer and the second current collection layer are doped semiconductor layers, and the doping types of the two are opposite.

15. The back contact battery according to claim 1, characterized in that Diffusion bands are formed on both sides of the first insulating block along the second direction, and the diffusion bands include at least one material in the slurry used to form the first insulating block; Along the second direction, the diffusion strip extends from an edge of the first insulating block to an edge of the adjacent first fine grid.

16. The back contact cell according to claim 15, characterized in that Along the thickness direction of the battery body, the thickness of the diffusion band is smaller than the thickness of the first fine grid.

17. The back contact battery according to claim 1, characterized in that The first fine grid includes first thickened segments spaced apart along the first direction, and along the second direction, the width of the first thickened segments is greater than the width of the remaining parts of the first fine grid; and / or, the second fine grid includes second thickened segments spaced apart along the first direction, and along the second direction, the width of the second thickened segments is greater than the width of the remaining parts of the second fine grid.

18. The back contact cell according to claim 17, characterized in that Along the second direction, the distance between the edge of the second thickened segment and its adjacent second insulating block is D3, D3≥50μm; and / or, along the second direction, the distance between the edge of the first thickened segment and its adjacent first insulating block is D4, D4≥50μm.

19. A photovoltaic module, characterized in that: A back-contact cell comprising the method of any one of claims 1-6 and 8-18; the back-contact cell further comprising a first conductive member extending along the second direction and directly physically and electrically connected to the first fine grid, or electrically connected to the first fine grid through a bonding layer.

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