Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact battery and a photovoltaic module. The back contact battery comprises a battery body which comprises a first surface and a second surface which are oppositely arranged; the plurality of first fine grids and the 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 sequentially and alternately arranged at intervals along the second direction; the first direction intersects with the second direction; the plurality of first insulating blocks are arranged at intervals along the second direction and respectively cover the second fine grids; in the second direction, the distance between the edges of the adjacent first insulating blocks is D1, and D1 is larger than or equal to 80 micrometers. The distance between every two adjacent first insulation blocks in the second direction is large enough, so that the safety distance for slurry flowing is reserved, the situation that the slurry forming the first insulation blocks flows to cover the first fine grids is avoided, the stability of electric connection between the first fine grids and the first conductive parts is guaranteed, and the service life of the first conductive parts is prolonged. And the stability of the performance of the back contact battery is improved.

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] The cell is the core component of the photovoltaic module, which can convert solar energy into electrical energy. Back-contact cells refer to cells in which the positive and negative grid lines are both set on the back of the cell to avoid the positive and negative grid lines blocking the front of the cell, thereby improving the photoelectric conversion efficiency of the cell.

[0003] In the prior art, when a solder strip or a main grid is used to connect the fine grid, an insulating block needs to be set between the solder strip or the main grid and the fine grid with opposite polarities. However, the insulating block often flows to cover the fine grid with the same polarity during the printing process, resulting in failure of the electrical connection between the solder strip or the main grid and the fine grid with the same polarity, thereby affecting the performance of the back contact battery. Summary of the invention

[0004] The purpose of the present 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 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: A back contact battery, comprising: The battery body comprises a first surface and a second surface which are arranged opposite to each other; 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 in sequence along the second direction; the first direction intersects with the second direction; A plurality of first insulating blocks are arranged at intervals along the second direction and respectively cover the plurality of second fine grids; along the second direction, a distance between edges of adjacent first insulating blocks is D1, and D1 is ≥ 80 μm.

[0006] During the process of printing and forming the first insulating block, the slurry may flow to cover the first fine grid, resulting in failure of the electrical connection between the first conductive member and the first fine grid. In view of the above situation, along the second direction, the distance between the edges of adjacent first insulating blocks is D1, and D1 ≥ 80 μm. With this technical solution, 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 battery performance.

[0007] In one implementation, along the thickness direction of the battery body, the thickness of the first insulating block is h1, 20μm≤h1≤100μm. This can ensure a good isolation effect between the second fine grid and the first conductive member, and prevent the slurry forming the first insulating block from climbing up to cover the first fine grid, thereby ensuring the reliability of the electrical connection between the first fine grid and the first conductive member, and also avoiding the waste of raw materials of the first insulating block.

[0008] 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 arrangement ensures that the side 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, and further ensuring the reliability of the electrical connection between the first fine grid and the first conductive member.

[0009] 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 grids, 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.

[0010] In one implementation, the intersection of the first conductive member and the first fine grid has a side protrusion protruding along the first direction. In this way, the side protrusion can increase 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 battery.

[0011] In one implementation, a depression is formed at the intersection of the top of the side protrusion and 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 that the transmission resistance is reduced.

[0012] In one implementation, the back contact battery further includes a plurality of second insulating blocks, which are arranged at intervals along the second direction and respectively cover the plurality of first fine grids; along the second direction, the distance between the edges of adjacent second insulating blocks is D2, D2≥80μm and / or D2≥D1. With this technical solution, the distance between two adjacent second insulating blocks along the second direction is large enough, thus reserving a safe distance for the slurry to flow, thereby avoiding the situation where the slurry flow forming the second insulating block covers the second fine grid, ensuring the stability of the electrical connection between the second fine grid and the second conductive member, and thus improving the stability of the back contact battery performance.

[0013] In one implementation, the back contact cell further includes a plurality of second insulating blocks, which are arranged at intervals along the second direction and respectively cover the plurality of 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; and / or S2 is 50μm-250μm greater than S1. This arrangement can reduce the amount of insulating material (e.g., insulating glue) in the second insulating block, while ensuring that the first current collection layer and the second current collection layer can be fully insulated.

[0014] In one implementation, 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 gate is respectively arranged in the first region, and the second fine gate is 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. In this way, the second fine gate in the groove structure will not be covered by the second insulating block (or covered by the diffusion belt), resulting in poor contact.

[0015] In one implementation, along the second direction, the distance between the edges of adjacent second insulating blocks is D2, D2>D1, and / or D2≥120μm. With this technical solution, the distance between two adjacent second insulating blocks along the second direction is large enough, thus reserving a safe distance for the slurry to flow, thereby avoiding the situation where the slurry flow forming the second insulating block covers the second fine grid, ensuring the stability of the electrical connection between the second fine grid and the second conductive member, and thus improving the stability of the back contact battery performance.

[0016] 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 grids, 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.

[0017] 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 in sequence 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 current types; There is an isolation region extending along the first direction between the adjacent first current collection layer and the second current collection layer; along the second direction, the isolation region between the adjacent first current collection layer and the second current collection layer is at least partially covered by the first insulating block. In this way, it can be prevented that during the welding process between the first fine grid 6 and the first conductive member 1, the bonding material overflows to the isolation region and connects to the second fine grid 4, causing a short circuit, thereby helping to improve the reliability of the back contact battery.

[0018] In one implementation, along the second direction, the width of the first insulating block extending to the first current collection layer adjacent thereto is L1, and L1 ≥ 40 μm. This technical solution ensures that after the first insulating block is cured, the reliability of the electrical connection between the first fine grid and the first conductive member is not affected to avoid the occurrence of cold solder joints. In addition, the first insulating block extends to the first current collection layer adjacent thereto, which can also prevent the slurry forming the first conductive member from overflowing to 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.

[0019] 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.

[0020] 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; Along the second direction, the diffusion band extends from the edge of the first insulating block to the edge of the first fine grid adjacent thereto. In the process of manufacturing the first insulating block, after the slurry is printed or laser transferred and before the slurry is solidified, one or more organic substances in the slurry diffuse to both sides of the first insulating block, forming diffusion bands on both sides of the first insulating block. The organic substances in the slurry forming the first insulating block diffuse to both sides, which can improve the adhesion between the first insulating block and the first surface and prevent the first insulating block from falling off.

[0021] In one implementation, along the thickness direction of the semiconductor substrate, the thickness of the diffusion zone is less than the thickness of the first fine gate. With this technical solution, the thickness of the first fine gate blocks 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.

[0022] In one implementation, the first fine grid includes a first thickened segment spaced apart along a first direction, and along a second direction, the width of the first thickened segment is greater than the width of the remaining portion of the first fine grid; with this technical solution, the provision of the first thickened segment 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.

[0023] 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 portion of the second fine grid. With this technical solution, 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.

[0024] 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. With this arrangement, a safe distance is reserved for the flow of slurry to prevent the slurry flow that forms 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.

[0025] And / or, along the second direction, the distance between the edge of the first thickened section and the adjacent first insulating block is D4, D4 ≥ 50 μm. In this way, a safe distance for the slurry to flow is reserved to prevent the slurry flowing to form the first insulating block from covering 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.

[0026] In one implementation, 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. With this technical solution, after the organic matter in the slurry of the main grid is mutually soluble with the organic matter in the slurry of the first insulating block, the adhesion between the first conductive member and the first insulating block is made stronger, further preventing the first conductive member from falling off.

[0027] A photovoltaic module comprises a back-contact cell as described above; the back-contact cell further comprises a first conductive member extending along a second direction and directly physically and electrically connected to a first fine grid, or electrically connected to the first fine grid through a bonding layer.

[0028] 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 elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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: Figure 1 An overall schematic diagram of a back contact battery provided in an embodiment of the present application; Figure 2 for Figure 1 A partial enlarged view of the middle B area; Figure 3 for Figure 1 A partial enlarged view of the middle A area; Figure 4 for Figure 1 Partial cross-sectional view along CC; Figure 5 for Figure 1 Partial cross-sectional view along DD; Figure 6 A schematic diagram of forming diffusion zones on both sides of a second insulating block provided in an embodiment of the present application; Figure 7 A cross-sectional view of diffusion bands formed on both sides of the second insulating block provided in an embodiment of the present application; Figure 8 A schematic diagram of forming a second conductive member provided in an embodiment of the present application; Fig. 9 A partial cross-sectional view of forming a second conductive member provided in an embodiment of the present application; Fig.10 A schematic diagram of a second fine grid partially thickened according to an embodiment of the present application; Fig.11 A schematic diagram of a first fine grid partially thickened according to an embodiment of the present application.

[0030] Reference numerals: 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

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can 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 can be directly connected to the other element or indirectly connected to the other element.

[0033] 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 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.

[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] See also Figure 1-Figure 2 The back contact battery provided in the embodiment of the present application includes a battery body, a first fine grid 6, a second fine grid 4 and a plurality of first insulating blocks 3. The battery body includes a first surface and a second surface opposite to each other, that is, two surfaces opposite to each other along the thickness direction of the battery body are the first surface and the second surface respectively. In the embodiment of the present application, the first surface corresponds to the backlight side of the back contact battery, also referred to as the back side; the second surface corresponds to the light-facing side of the back contact battery, also referred to as the front side.

[0037] A plurality of first fine grids 6 and a plurality of second fine grids 4 are arranged on the first surface; the first fine grids 6 and the second fine grids 4 extend along the first direction, and the plurality of first fine grids 6 and the plurality of second fine grids 4 are arranged alternately and spaced in sequence along the second direction. In some embodiments, the first surface has a first region, a second region and an isolation region 2, wherein the first region and the second region are alternately and spaced along the second direction, and an isolation region 2 is provided between the first region and the second region. The first region and the second region extend along the first direction, that is, the lengths of the first region and the second region extend along the first direction. The first direction and the second direction intersect, that is, the first direction is different from the second direction, and the angle between the first direction and the second direction can be an acute angle or a right angle. The first direction can be the length direction of the battery body or the width direction of the battery body. When the first direction is the length direction of the battery body, the second direction is the width direction of the battery body; when 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 grid 6 is arranged in the first region and extends along the first direction, and the second fine grid 4 is arranged in the second region and extends along the first direction.

[0038] 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. In the process of printing and forming the first insulating blocks 3, the slurry may flow to cover the first fine grids 6, resulting in failure of the electrical connection between the first fine grids 6 and other components (such as the first conductive member 1). Figure 2 As shown, along the second direction, the distance between the edges of adjacent first insulating blocks 3 is D1, and D1 ≥ 80 μm. With this technical solution, the distance between two adjacent first insulating blocks 3 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 flow of the first insulating block 3 covers the first fine grid 6, ensuring the stability of the electrical connection between the first fine grid 6 and other components, and thus improving the stability of the back contact battery performance.

[0039] 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.

[0040] Theoretically, the larger the distance between two first insulating blocks 3 adjacent to each other along the second direction, the better. However, since the width of the current collecting layer cannot be too wide, the maximum distance between two first insulating blocks 3 adjacent to each other along the second direction cannot be greater than 1000 μm.

[0041] In some embodiments, the battery body includes a semiconductor substrate, a first current collection layer 7 and a second current collection layer 5. The two opposite sides of the semiconductor substrate along its thickness direction correspond to the first surface and the second surface respectively. The first current collection layer 7 and the second current collection layer 5 extend along the first direction, and the first current collection layer 7 and the second current collection layer 5 are alternately arranged in sequence along the second direction. The first current collection layer 7 is at least formed in the first region, specifically, the first current collection layer 7 can be formed only in the first region, or the first current collection layer 7 is formed in the first region and the isolation region 2. The second current collection layer 5 is at least formed in the second region, specifically, the second current collection layer 5 can be formed only in the second region, or the second current collection layer 5 is formed in the second region and the isolation region 2. When the first current collection layer 7 is formed in the first region and the isolation region 2, and the second current collection layer 5 is formed in the second region and the isolation region 2, the first current collection layer 7 and the second current collection layer 5 overlap in the isolation region 2. The first current collection layer 7 and the second current collection layer 5 collect opposite types of currents, so as to collect and export electrons and holes respectively, which is conducive to the formation of photocurrent.

[0042] The first fine grid 6 is arranged 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 arranged 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 to the isolation region and connecting to the second fine grid 4, resulting in a short circuit phenomenon, thereby helping to improve the reliability of the back contact battery.

[0043] In other embodiments, the back contact cell further comprises a first conductive member 1, the first conductive member 1 extends along the second direction, and the first conductive member 1 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. The first insulating block 3 is disposed 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, so as to prevent the electrical connection between the second fine grid 4 and the first conductive member 1 from being short-circuited, thereby affecting the photoelectric conversion efficiency of the cell. Figure 2As shown, along the second direction, the distance between the edges of adjacent first insulating blocks 3 is D1, and D1 ≥ 80 μm. With this technical solution, the distance between two adjacent first insulating blocks 3 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 flow of the first insulating block 3 covers the first fine grid 6, ensuring the stability of the electrical connection between the first fine grid 6 and the first conductive member 1, and thus improving the stability of the back contact battery performance.

[0044] In the process of printing and forming the first conductive member 1, the paste (such as copper) forming the first conductive member 1 easily flows through the isolation region 2 to the second current collecting layer 5, resulting in leakage. In view of the above situation, in some embodiments, such as Figure 2 As shown, along the second direction, the first insulating block 3 extends to the first current collection layer 7 adjacent thereto. 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. This technical solution ensures that after the first insulating block 3 is cured, the reliability of the electrical connection between the first fine grid 6 and the first conductive member 1 is not affected, 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 thereto, and it can also prevent the slurry forming the first conductive member 1 from overflowing to the isolation region 2 or the second current collection layer 5, and connecting to the second fine grid 4, causing a short circuit in the battery cell, thereby helping to improve the reliability of the battery string.

[0045] Furthermore, along the second direction, the width of the first insulating block 3 extending to the first current collecting layer 7 adjacent thereto is L1, and L1 ≥ 40 μm. This arrangement 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. Exemplarily, L1 may 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.

[0046] 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, more slurry is needed to easily climb to cover the first fine grid 6 during the formation of the first insulating block 3, 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, along the thickness direction of the battery body, the thickness of the first insulating block 3 is h1, 20μm≤h1≤100μm, so that a good isolation effect between the second fine grid 4 and the first conductive member 1 can be guaranteed, and the slurry forming the first insulating block 3 can be prevented from climbing 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, and also avoiding the waste of raw materials of the first insulating block 3.

[0047] Exemplarily, 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.

[0048] It can be understood that, along the thickness direction of the battery body, the higher the height of the first fine grid 6 is, the less likely it is that the slurry forming the first insulating block 3 will climb to the upper surface of the first fine grid 6, that is, when the height of the first fine grid 6 is high, the first fine grid 6 has a function similar to that of a dam, and at this time, the side of the first fine grid 6 can block the flow of the slurry forming the first insulating block 3, and prevent the slurry forming the first insulating block 3 from climbing to cover the upper surface of the first fine grid 6. In view of the above situation, in some embodiments, along the thickness direction 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, and h1 / h2≤4. In this way, it can be ensured that the side of the first fine grid 6 can block the slurry forming the first insulating block 3, and prevent the slurry forming the first insulating block 3 from climbing 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.

[0049] 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.

[0050] In other embodiments, the back contact battery further includes a plurality of second insulating blocks 9, which are arranged at intervals along the second direction and respectively cover the plurality of first fine grids 6. In the process of printing and forming the second insulating blocks 9, the slurry may flow to cover the second fine grids 4, resulting in failure of the electrical connection between the second fine grids 4 and other components (such as the second conductive member 8). Figure 3 As shown, along the second direction, the distance between the edges of adjacent second insulating blocks 9 is D2, D2≥80μm and / or D2≥D1. With this technical solution, the distance between two adjacent second insulating blocks 9 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 flow forming the second insulating block 9 covers the second fine grid 4, ensuring the stability of the electrical connection between the second fine grid 4 and the second conductive member 8, and thus improving the stability of the back contact battery performance.

[0051] 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.

[0052] The first insulating block 3 and / or the second insulating block 9 may be in any shape such as circular, rectangular, elliptical, etc.

[0053] In some embodiments, the back contact cell further includes a second conductive member 8, which extends along the second direction, and is electrically connected to the plurality of second fine grids 4, so as to collect the current collected by the plurality of second fine grids 4 through the second conductive member 8, and transmit the collected current to an external circuit. A second insulating block 9 corresponding to the first fine grid 6 is provided at the intersection of the second conductive member 8 and the first fine grid 6, so as to block the first fine grid 6 and the second conductive member 8 through the second insulating block 9, so as to prevent a short circuit phenomenon from occurring in the electrical connection between the first fine grid 6 and the second conductive member 8, thereby affecting the photoelectric conversion efficiency of the cell.

[0054] In one embodiment, if Figure 2 As shown, along the second direction, the width of the first insulating block 3 is S2, 300μm≤S2≤800μm, so as to prevent the width of the first insulating block 3 from being too small and failing to completely isolate the second fine grid 4 and the first conductive member 1, and to prevent the width of the first insulating block 3 from being too large and wasting raw materials. Exemplarily, S2 can be 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm or 800μm, etc. In addition, along the second direction, the width of the second current collection layer 5 is W1, 200μm≤W1≤650μm, for example, W1 is 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm or 650μm, etc.

[0055] In addition, along the second direction, the width of the isolation region 2 is W3, 40μm≤W3≤100μm, so as to prevent the width of the isolation region 2 from being too small to cause leakage, and to prevent the width of the isolation region 2 from being too large to affect the collection efficiency of carriers. Exemplarily, W3 can be 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or 100μm, etc.

[0056] In one embodiment, if Figure 3As shown, along the second direction, the width of the second insulating block 9 is S1, 200μm≤S1≤650μm, so as 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, and to prevent 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 collection layer 7 is W2, 200μm≤W2≤600μm, for example, W2 is 220μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm or 600μm, etc.

[0057] 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 may be 50 μm, 100 μm, 150 μm, 200 μm or 250 μm, etc. In this way, the insulating material (such as insulating glue) of the second insulating block 9 can be reduced, while ensuring that the first current collection layer 7 and the second current collection layer 5 can be fully insulated.

[0058] like Figure 4 and Figure 5 As shown, in some embodiments, the second region has a groove structure, and the groove structure is recessed relative to the first region toward the second surface, that is, the groove structure is arranged lower than the rest of the first surface. The second current collection layer 5 is located in the groove structure. Specifically, the second current collection layer 5 is located at the bottom of the groove structure, and the first current collection layer 7 is located in the area of ​​the first surface except the groove structure. In this way, the presence of the groove structure can at least partially stagger the electrode structures electrically connected to the first current collection layer 7 and the second current collection layer 5 respectively along the thickness direction of the battery body, which is conducive to suppressing leakage.

[0059] In the case where the second region has a groove structure, such as Figure 4As shown, in the process of forming the second insulating block 9, the slurry forming the second insulating block 9 is more likely to flow into the groove structure along the M direction under the action of gravity, resulting in the slurry forming the second insulating block 9 being more likely to cover the second fine grid 4 when the second region has a groove structure. In view of the above situation, in this technical solution, along the second direction, the distance between the edges of adjacent second insulating blocks 9 is D2, D2>D1, or D2≥120μm. In this way, the distance between two adjacent second insulating blocks 9 along the second direction is further increased, further ensuring the stability of the electrical connection between the second fine grid 4 and the second conductive member 8. At this time, 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 50-250μm, so that the second fine grid 4 in the groove structure will not be covered by the second insulating block 9 (or covered by the diffusion band), resulting in poor contact.

[0060] 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.

[0061] It can be understood that when the second region has a groove structure, the deeper the groove structure is, the more the slurry for 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 for forming the second insulating block 9.

[0062] 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 can be understood that the isolation region 2 can also cross the step surface or be 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 may be on the step; for another example, when the current collection layer is a doped layer, the isolation region 2 may be in the groove, and the doped layer may be a polysilicon layer, and there may also be a tunneling layer underneath.

[0063] 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, and the diffusion bands 10 include at least one material in the slurry used to form the first insulating block 3. That is, in the process of making 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 to both sides of the first insulating block 3, forming diffusion bands 10 on both sides of the first insulating block 3. The organic substances in the slurry forming the first insulating block 3 diffuse to both sides, which can improve the adhesion between the first insulating block 3 and the first surface and prevent the first insulating block 3 from falling off.

[0064] In addition, the diffusion tape 10 made of organic material can reduce the height difference between the diffusion tape 10 and the first insulating block 3, which can reduce the amount of printing paste used for the main grid (first conductive member 1); or, in the absence of a main grid, it can reduce the amount of bonding layer material used at the junction of the welding tape and the grid line. In this embodiment, the diffusion tape 10 is at least one organic material such as epoxy resin, photocuring agent or photoinitiator of the insulating block material, and its inorganic filler should be less than 20%wt, so as to ensure that the organic matter in the first insulating block 3 can be spread and extend to the side of the first fine grid 6, and by controlling the spacing between the two first insulating blocks 3 to be greater than or equal to 80μm, the diffusion tape 10 has a certain height and does not cover the first fine grid 6.

[0065] 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 first fine grid 6 adjacent thereto. 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, and the side of the first fine grid 6 blocks the slurry from continuing to extend and flow, thereby ensuring the stability of the electrical connection between the first fine grid 6 and the first conductive member 1.

[0066] In some embodiments, the material of the first insulating block 3 and / or the second insulating block 9 may include UV curing glue to ensure the formation of a diffusion band 10 of suitable thickness. In addition, the material of the first conductive member 1 and / or the second conductive member 8 may include base metal slurry, such as copper slurry. The material of the first fine grid 6 and the second fine grid 4 may include silver, copper, etc.

[0067] 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.

[0068] In other embodiments, Fig. 9As shown, along the second direction, diffusion bands 10 are formed on both sides of the second insulating block 9, and the diffusion bands 10 include at least one material in the slurry used to form the second insulating block 9. That is, in the process of making the second insulating block 9, after the slurry is printed or laser transferred, and before the slurry is solidified, one or more organic substances in the slurry diffuse to both sides of the second insulating block 9, and diffusion bands 10 are formed on both sides of the second insulating block 9. Along the second direction, the diffusion band 10 extends from the edge of the second insulating block 9 to the edge of the second fine grid 4 adjacent thereto. In this arrangement, since the second insulating block 9 has a certain thickness, the second conductive member 8 spanning the position where the second insulating block 9 is provided and the position where the second insulating block 9 is not provided has a certain height difference, and the diffusion band 10 has a certain thickness. The formation of the diffusion band 10 can reduce the height difference of the second conductive member 8 spanning the first area and the second area, making the surface of the battery cell smoother, which is conducive to subsequent packaging; its effect is similar to that of the diffusion band 10 between the two first insulating blocks 3, and will not be repeated here.

[0069] like Figure 8 As shown, the intersection of the first conductive member 1 and the first fine grid 6 has a side protrusion 81 protruding along the first direction. That is, along the first direction, the width of the position where the first conductive member 1 has the side protrusion 81 is greater than the width of the other positions of the first conductive member 1. In this way, the side protrusion 81 can increase the contact area between the first conductive member 1 and the first fine grid 6, thereby reducing the transmission resistance between the first conductive member 1 and the first fine grid 6, reducing current loss, and improving the photoelectric conversion efficiency of the back contact battery. In addition, in this technical solution, when there are diffusion strips 10 on both sides of the first fine grid 6, the diffusion strips 10 can limit the slurry forming the first conductive member 1 from flowing too far in the first direction, and the formed side protrusion 81 is too wide.

[0070] In some embodiments, 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, which further saves the raw materials of the first conductive member 1 while ensuring the reduction of the transmission resistance.

[0071] In other embodiments, Fig.10As shown, the first fine grid 6 includes first thickened segments 61 spaced apart along the first direction, and 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. That is, the first thickened segment 61 is arranged at the position where the first fine grid 6 is connected to the first conductive member 1, and the first thickened segment 61 can be integrally formed with the remaining portion of the first fine grid 6, or can be formed by processing separately. With this technical solution, the arrangement of the first thickened segment 61 can increase 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, reducing current loss, and improving the photoelectric conversion efficiency of the back contact battery.

[0072] Further, such as Fig.10 As shown, along the second direction, the distance between the edge of the first thickened section 61 and the adjacent first insulating block 3 is D4, and D4 ≥ 50 μm. In this way, a safe distance for the slurry flow is reserved to prevent the slurry flow forming the first insulating block 3 from covering the first thickened section 61, thereby 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. Exemplarily, D4 can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, etc.

[0073] In addition, if Fig.11 As shown, the second fine grid 4 includes second thickened segments 41 spaced apart along the first direction, and 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. That is, the second thickened segment 41 is arranged at the position where the second fine grid 4 is connected to the second conductive member 8, and the second thickened segment 41 can be integrally formed with the rest of the second fine grid 4, or can be formed by processing separately. With this technical solution, the arrangement of the second thickened segment 41 can increase 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, reducing the current loss, and improving the photoelectric conversion efficiency of the back contact battery.

[0074] Further, such as Fig.11 As shown, along the second direction, the distance between the edge of the second thickened section 41 and the adjacent second insulating block 9 is D3, and D3 ≥ 50 μm. In this way, a safe distance for the slurry flow is reserved to prevent the slurry flow forming the second insulating block 9 from covering the second thickened section 41, thereby 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. Exemplarily, D3 can be 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, etc.

[0075] In some embodiments, the first conductive member 1 is a main grid, and the back contact battery is a main grid battery, 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 3. With this technical solution, after the organic matter in the slurry of the main grid is mutually soluble with the organic matter in the slurry of the first insulating block 3, the adhesion between the first conductive member 1 and the first insulating block 3 is made stronger, further preventing the first conductive member 1 from falling off.

[0076] 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.

[0077] In addition, in some embodiments, the back contact battery further includes a first doping layer and a second doping layer, 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. For example, the first doping layer is formed in the first region and the isolation region 2, the second doping layer is formed in the second region and the isolation region 2, and the first doping layer and the second doping layer are overlapped in the isolation region 2. For another example, the first doping layer is only formed in the first region, and the second doping layer is only formed in the second region. The first doping layer can be additionally formed on the semiconductor substrate by deposition technology, or can be formed in the semiconductor substrate by diffusion, ion implantation, etc.

[0078] 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.

[0079] In addition, the materials of the first doping layer and the second doping layer may be silicon (Si), germanium (Ge), silicon carbide (SiCx) or gallium arsenide (GaAs), etc. Taking the case where the materials of the first doping layer and the second doping layer are both silicon (Si) as an example, the first doping layer may be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The second doping layer may also be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon.

[0080] 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, the second doped layer is formed in the second region and the isolation region 2, and 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 away from the semiconductor substrate, and the second current collection layer 5 is arranged on the side of the second doped layer 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 conductivity, can timely guide the collected carriers, reduce the carrier recombination rate, and the transparent conductive layer can reduce the contact resistance between the first doped layer and the second doped layer and the electrode.

[0081] For the above-mentioned transparent conductive layer, the embodiment of the present invention does not specifically limit the material and thickness of the transparent conductive layer. Exemplarily, 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 film or a laminated film. Exemplarily, the thickness of the transparent conductive layer may be greater than or equal to 10 nm and less than or equal to 100 nm.

[0082] In addition, when both the first doping layer and the second doping layer are doped polysilicon layers, the first doping layer is formed only in the first region, and the second doping layer is formed only in the second region; or, the first doping layer is formed in the first region and the isolation region 2, and the second doping layer is formed in the second region and the isolation region 2, the first doping layer and the second doping layer are overlapped in the isolation region 2, and an opening penetrating the thickness of the first doping layer and the second doping layer is provided in the isolation region 2 to isolate the first doping layer and the second doping layer from 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 the first doping layer, and the second current collection layer 5 is the second doping layer.

[0083] In addition, the embodiment of the present application further provides a photovoltaic module, which includes the back contact cell provided by any of the above embodiments. The first conductive member 1 included in the back contact cell extends along the second direction and is directly physically and electrically connected to the first fine grid 6, or is electrically connected to the first fine grid 6 through a bonding layer. 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 back contact cell, which will not be repeated here.

[0084] In the photovoltaic module, the first conductive member 1 is a welding strip, which connects at least two back-contact cells to form a cell structure (i.e., a cell string structure). At this time, the back-contact cell is a main grid-free cell, and the welding strip is electrically connected to the first fine grid 6 through a bonding layer. The bonding layer can be specifically solder or a conductive adhesive. With this technical solution, the welding strip is directly electrically connected to the first fine grid 6, thereby reducing the effect of shielding and resistance loss. When the first conductive member is the main grid, the photovoltaic module will further include a welding strip, which needs to be welded to the main grid through a bonding material, so as to realize the series or parallel connection of multiple cells at the module end.

[0085] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0086] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A back contact battery, characterized in that: include: The battery body comprises a first surface and a second surface which are 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 with the second direction; A plurality of first insulating blocks are arranged at intervals along the second direction and respectively cover a plurality of second fine grids; along the second direction, a distance between edges of adjacent first insulating blocks is D1, and D1≥80 μm.

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

3. The back contact cell 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 cell 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 cell 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 cell 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 cell 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 cell according to claim 1, characterized in that: The back contact battery also includes a plurality of second insulating blocks, which are arranged at intervals along the second direction and respectively cover a plurality of the first fine grids; along the second direction, the distance between the edges of adjacent second insulating blocks is D2, D2≥80μm and / or D2≥D1.

9. The back contact cell 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 cell according to claim 1, characterized in that: The back contact battery also includes a plurality of second insulating blocks, which are arranged at intervals along the second direction and respectively cover a plurality of the 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; and / or S2 is 50μm-250μm greater than S1.

11. The back contact cell according to claim 10, characterized in that: The first surface has a first area and a second area alternately arranged in sequence along a second direction, the first area and the second area extend along the first direction, the first fine grids are respectively arranged in the first area, and the second fine grids are respectively arranged in the second area; the second area is a groove structure, and the groove structure is recessed relative to the first area toward the second surface.

12. The back contact cell according to claim 8 or 11, characterized in that: Along the second direction, a distance between edges of adjacent second insulating blocks is D2, D2>D1, and / or D2≥120 μm.

13. The back contact cell according to claim 1, characterized in that: The battery body comprises: 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, 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; 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.

14. The back contact cell according to claim 13, 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 ≥ 40 μm.

15. The back contact cell according to claim 13, 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.

16. The back contact cell 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 first fine grid adjacent thereto.

17. The back contact cell according to claim 16, 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.

18. The back contact cell 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 rest 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 rest of the second fine grid.

19. The back contact cell according to claim 18, characterized in that The back contact battery further includes a plurality of second insulating blocks which are arranged at intervals along the second direction and respectively cover the plurality of first fine grids; 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.

20. A photovoltaic module, characterized in that: A back-contact battery comprising the following claims; the back-contact battery 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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