Back contact battery, battery assembly and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system. The back contact cell includes: a silicon substrate including a first edge extending in a first direction; the first polarity fine grids and the second polarity fine grids are arranged on the silicon substrate, extend in the first direction and are arranged in the second direction, and the second direction intersects with the first direction; the first main grid is arranged on the silicon substrate, extends along the second direction, is connected with the first polarity fine grid and is separated from the second polarity fine grid; the plurality of connecting structures are arranged along the second direction, are arranged on the first main grid, are used for connecting the serial connection pieces and comprise end part connecting blocks, and the end part connecting blocks are connecting structures closest to the first edge; the second polarity fine grid comprises a first fine grid and a second fine grid which are both positioned between the end part connecting block and the first edge; in the first direction, the distance from the first fine grid to the first main grid is larger than the distance from the second fine grid to the first main grid.

Description

Technical Field

[0001] The present application belongs to the technical field of solar cells, and in particular relates to a back-contact cell, a cell assembly and a photovoltaic system. Background Art

[0002] Solar cell power generation is a sustainable source of clean energy, utilizing the photovoltaic effect of semiconductor pn junctions to convert sunlight into electricity. A cell in which both grid lines of two polarities are located on the same side of the cell is called a back-contact cell. Typically, electrical connectors such as solder strips and conductive wires are used to connect the grid lines of one polarity in a back-contact cell to the grid lines of the other polarity in an adjacent back-contact cell to form a cell string. Insulating adhesive is then used to isolate the solder strips from the grid lines of the wrong polarity. However, the tips of the electrical connectors can easily come into contact with the grid lines of the wrong polarity, causing the cell string to short-circuit.

[0003] Based on this, how to reduce the risk of short circuit caused by the head of the electrical connector contacting the grid line with incorrect polarity has become an urgent problem to be solved. Summary of the Invention

[0004] The present application provides a back-contact battery, battery assembly and photovoltaic system, aiming to solve the problem of how to reduce the risk of short circuit caused by the head of the electrical connector contacting the grid line with mismatched polarity.

[0005] The back contact battery provided in this application includes: A silicon substrate comprising a first edge extending along a first direction; A plurality of first polarity fine gates and a plurality of second polarity fine gates spaced apart from each other are provided on the silicon substrate, extend along the first direction, and are arranged along a second direction, wherein the second direction intersects the first direction; a first main gate, provided on the silicon substrate, extending along the second direction, connecting the first polarity fine gate and spaced apart from the second polarity fine gate; a plurality of connection structures arranged along the second direction and provided on the first main grid for connecting series components, including an end connection block, wherein the end connection block is the connection structure closest to the first edge; The second polarity fine gate includes a first fine gate and a second fine gate, both located between the end connection block and the first edge; in the first direction, the distance between the first fine gate and the first main gate is greater than the distance between the second fine gate and the first main gate.

[0006] Specifically, a difference between a distance between the first fine grid and the first main grid and a distance between the second fine grid and the first main grid is 0.1 mm to 0.8 mm.

[0007] Specifically, the back contact cell satisfies the following formula: 0.2≤A / B≤0.9; Wherein, A is the number of the first fine grids, and B is the number of the second polarity fine grids between the end connecting block and the first edge.

[0008] Specifically, there are a plurality of first fine grids, and the plurality of first fine grids are sequentially arranged along the second direction, and a distance between a first first fine grid and a last first fine grid is 1 mm to 3 mm.

[0009] Specifically, the silicon substrate includes a second edge extending along the second direction, the first main gate includes an edge main gate, and the edge main gate is the first main gate closest to the second edge; the second polarity fine gate includes a third fine gate and a fourth fine gate, the third fine gate is located between the edge main gate and the second edge, and the fourth fine gate is located between the edge main gate and the first edge; The back contact battery includes a second main grid and a first connecting grid, wherein the second main grid is connected to the second polarity fine grid and is spaced apart from the first polarity fine grid; the first connecting grid is located between the edge main grid and the second edge, connects several of the third fine grids, and is connected to the second main grid through the fourth fine grid.

[0010] Specifically, the connection structure includes a non-end connection block, and the non-end connection block is located on a side of the end connection block away from the first edge; The back-contact battery includes a fifth fine grid, a sixth fine grid and a second connecting grid. The fifth fine grid is located between the non-end connecting block and the second edge, and the sixth fine grid is located between the non-end connecting block and the connecting structure adjacent in the second direction; the second connecting grid is located between the non-end connecting block and the second edge, connects several of the fifth fine grids, and is connected to the second main grid through the sixth fine grid.

[0011] Specifically, the length of the first connection gate is greater than the length of the second connection gate.

[0012] Specifically, the back contact cell satisfies the following formula: 1.1≤C / D≤4; Wherein, C is the number of the second polarity fine gates connected to the first connecting gate, and B is the number of the second polarity fine gates connected to the second connecting gate.

[0013] The battery assembly provided in the present application includes any of the above-mentioned back-contact batteries.

[0014] The photovoltaic system provided in this application includes any of the above-mentioned battery components.

[0015] In the back-contact cell, cell assembly, and photovoltaic system of the embodiments of the present application, since the first fine grid and the second fine grid are both located between the end connection block and the first edge and the spacing from the first fine grid to the first main grid is greater than the spacing from the second fine grid to the first main grid, the spacing from some of the opposite-sex fine grids between the end connection block and the first edge to the first main grid is larger, leaving space for the head of the serial connector connected to the end connection block and located between the end connection block and the first edge, so that the distance between the head of the serial connector and the fine grids of non-corresponding polarity is farther, reducing the risk of short circuit caused by contact between the head of the serial connector and the fine grids of non-corresponding polarity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a partial structure of a back-contact battery according to an embodiment of the present application; Figure 2 1 is a schematic structural diagram of a back-contact battery according to an embodiment of the present application; Figure 3 is a schematic diagram of a partial structure of a back-contact battery according to an embodiment of the present application; Description of main component symbols: Back contact cell 100, silicon substrate 101, first edge 1011, second edge 1012, first polarity fine grid 10, second polarity fine grid 20, first fine grid 21, second fine grid 22, third fine grid 23, fourth fine grid 24, fifth fine grid 25, sixth fine grid 26, first polarity main grid 30, first main grid 31, edge main grid 311, second polarity main grid 40, second main grid 41, end connection block 51, non-end connection block 52, first connection grid 61, second connection grid 62; The distance w1 between the first fine gate and the first main gate, the distance w2 between the second fine gate and the first main gate, the distance d between the first first fine gate and the last first fine gate, the length L1 of the first connecting gate, and the length L2 of the second connecting gate. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0018] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship 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 orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0020] 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, electrical connections, or mutual communication; 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 specific circumstances.

[0021] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0022] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0023] See also Figure 1 and Figure 2 The back contact battery 100 of the embodiment of the present application includes: The silicon substrate 101 includes a first edge 1011 extending along a first direction; A plurality of first polarity fine gates 10 and a plurality of second polarity fine gates 20 are spaced apart from each other and are disposed on a silicon substrate 101, extending along a first direction and arranged along a second direction, the second direction intersecting the first direction; A first main gate 31 is provided on the silicon substrate 101, extends along the second direction, connects the first polarity fine gate 10 and is spaced apart from the second polarity fine gate 20; A plurality of connection structures arranged along the second direction and provided on the first main grid 31 for connecting the serial components, including an end connection block 51, which is the connection structure closest to the first edge 1011; The second polarity fine gate 20 includes a first fine gate 21 and a second fine gate 22, both located between the end connection block 51 and the first edge 1011; in the first direction, the spacing w1 from the first fine gate 21 to the first main gate 31 is greater than the spacing w2 from the second fine gate 22 to the first main gate 31.

[0024] In the back-contact battery 100 of the embodiment of the present application, since the first fine grid 21 and the second fine grid 22 are both located between the end connection block 51 and the first edge 1011 and the spacing between the first fine grid 21 and the first main grid 31 is greater than the spacing between the second fine grid 22 and the first main grid 31, the spacing between some of the opposite-sex fine grids between the end connection block 51 and the first edge 1011 and the first main grid 31 is larger, leaving space for the head of the series component connected to the end connection block 51 and located between the end connection block 51 and the first edge 1011, so that the distance between the head of the series component and the fine grids of non-corresponding polarity is farther, reducing the risk of short circuit caused by the head of the series component contacting the fine grids of non-corresponding polarity.

[0025] Specifically, the back contact cell 100 may be a sliced ​​cell formed by cutting a whole cell. Figure 2A half-cell battery is formed by cutting a whole cell in half. The back contact cell 100 may also be a whole cell that has not been cut. The whole cell back contact cell 100 may include a slicing groove, and the whole cell may be cut along the slicing groove to obtain Figure 2 The whole back contact battery 100 can be asymmetrical or symmetrical along the slicing groove.

[0026] Specifically, the silicon base 101 may include a silicon substrate, a first polarity doped layer, a second polarity doped layer, and a dielectric film layer. Furthermore, the silicon substrate may be a P-type or N-type silicon substrate; a single crystal or polycrystalline silicon substrate. The specific form of the silicon substrate is not limited herein. Furthermore, the first polarity doped layer and the second polarity doped layer are disposed on the silicon substrate. The first polarity doped layer and the second polarity doped layer have different doping polarities. The two doped layers can be formed by diffusion into the silicon substrate or by depositing a film layer on the silicon substrate. It will be understood that, in the thickness direction of the back-contact cell 100, the first polarity doped layer is stacked on the silicon substrate, and the second polarity doped layer is stacked on the silicon substrate. In a plane perpendicular to the thickness direction of the back-contact cell 100, the first polarity doped layer and the second polarity doped layer are distributed in different regions, corresponding to the first polarity doped region and the second polarity doped region, respectively.

[0027] Furthermore, a dielectric film layer can overlie both the first-polarity doped layer and the second-polarity doped layer. The first-polarity fine gate 10 passes through the dielectric film layer to contact the first-polarity doped layer, while the second-polarity fine gate 20 passes through the dielectric film layer to contact the second-polarity doped layer. In this manner, the dielectric film layer electrically isolates the first-polarity doped layer from the second-polarity doped layer, while also reducing light reflection and recombination. The dielectric film layer can also be disposed between at least one pair of adjacent first-polarity doped regions and second-polarity doped regions to electrically isolate the first-polarity doped region from the second-polarity doped region.

[0028] Specifically, the first polarity fine gate 10 and the second polarity fine gate 20 may be distributed in the entire region of the silicon substrate 101 ; the first polarity fine gate 10 and the second polarity fine gate 20 may be distributed in a partial region of the silicon substrate 101 .

[0029] Specifically, the first polarity fine gate 10 and the second polarity fine gate 20 have different polarities. The first polarity fine gate 10 corresponds to the first polarity doping layer and the first polarity doping region, while the second polarity fine gate 20 corresponds to the second polarity doping layer and the second polarity doping region.

[0030] Specifically, the number of first polarity fine grids 10 can be 1, 2, 3, 4, or another number. The number of second polarity fine grids 20 can be 1, 2, 3, 4, or another number. This is not limited herein. The number of first polarity fine grids 10 and the number of second polarity fine grids 20 can be the same or different.

[0031] Specifically, the first polarity fine grid 10 and the second polarity fine grid 20 extend along the first direction, which means that the overall extension direction is the first direction. This does not limit the specific form of the first polarity fine grid 10 and the second polarity fine grid 20. In this embodiment, the first polarity fine grid 10 and the second polarity fine grid 20 are linear, and the extension direction of the first polarity fine grid 10 and the second polarity fine grid 20, that is, the first direction, is the length direction of the first polarity fine grid 10 and the second polarity fine grid 20. In other embodiments, the first polarity fine grid 10 can be wavy, zigzag, or other shapes. The second polarity fine grid 20 can be wavy, zigzag, or other shapes.

[0032] Specifically, the first polarity fine grids 10 and the second polarity fine grids 20 are arranged along the second direction, and may be arranged alternately or non-alternatingly, and may be arranged at equal intervals or at unequal intervals along the second direction, which is not limited here.

[0033] Specifically, the first polarity fine grid 10 and the second polarity fine grid 20 are spaced apart, which means that a gap is formed between adjacent first polarity fine grids 10 and second polarity fine grids 20. The gap may be filled with an insulating member or may be an air gap.

[0034] See also Figure 2 The back-contact cell 100 may include a plurality of first polarity busbars 30 and a plurality of second polarity busbars 40 spaced apart from one another, disposed on a silicon substrate 101, extending along a second direction, and arranged along a first direction. The first polarity busbars 30 connect to a plurality of first polarity fine grids 10 and are spaced apart from the second polarity fine grids 20. The second polarity busbars 40 connect to a plurality of second polarity fine grids 20 and are spaced apart from the first polarity fine grids 10.

[0035] Specifically, the first polarity busbar 30 and the second polarity busbar 40 extend along the second direction, meaning that the overall extension direction is the second direction. This does not limit the specific form of the first polarity busbar 30 and the second polarity busbar 40. In this embodiment, the first polarity busbar 30 and the second polarity busbar 40 are linear, and the extension direction of the first polarity busbar 30 and the second polarity busbar 40, i.e., the second direction, is the length direction of the first polarity busbar 30 and the second polarity busbar 40. In other embodiments, the first polarity busbar 30 may be wavy, zigzag, or other forms. The second polarity busbar 40 may be wavy, zigzag, or other forms.

[0036] Specifically, the first polarity busbars 30 and the second polarity busbars 40 are arranged along the first direction, and may be arranged alternately or non-alternatingly, and may be arranged at equal intervals or at unequal intervals along the first direction, which is not limited here.

[0037] Specifically, the first polarity busbar 30 and the second polarity busbar 40 are spaced apart, which means that a gap is formed between adjacent first polarity busbars 30 and second polarity busbars 40. The gap may be filled with an insulating member or may be an air gap.

[0038] Specifically, the first polarity bus gate 30 includes a first bus gate 31 , and the second polarity bus gate 40 includes a second bus gate 41 .

[0039] exist Figure 2 In the example, the first polarity main gates 30 are all first polarity main gates 31, that is, for each first polarity main gate 30, between the corresponding end connection block 51 and the first edge 1011, there is a part of the second polarity fine gates 20 with a spacing from the first polarity main gate 30 that is greater than the spacing from the remaining second polarity fine gates 20 to the first polarity main gate 30.

[0040] It is understandable that in other examples, part of the first polarity bus gates 30 may be the first bus gates 31 , and the remaining first polarity bus gates 30 may not meet the characteristics of the first bus gates 31 .

[0041] exist Figure 2 In the example, for each second polarity busbar 40, between the corresponding end connection block 51 and the first edge 1011, there is a portion of the first polarity fine grid 10 where the distance from the second polarity busbar 40 is greater than the distance from the remaining first polarity fine grid 10 to the second polarity busbar 40. For the explanation and description of this portion, refer to the explanation and description of the first busbar 31 and will not be repeated here to avoid redundancy.

[0042] It can be understood that in other examples, it is also possible that, for some of the second polarity main grids 40, between the corresponding end connection block 51 and the first edge 1011, the spacing between some of the first polarity fine grids 10 and the second polarity main grid 40 is greater than the spacing between the remaining first polarity fine grids 10 and the second polarity main grid 40.

[0043] See also Figure 2 The back contact battery 100 includes a plurality of connection structures, which are arranged along the second direction and are provided on the first main grid 31 for connecting series components, including an end connection block 51, which is the connection structure closest to the first edge 1011.

[0044] Specifically, the connection structure and the serial connection member can be electrically connected through at least one of conductive adhesive bonding, direct soldering, solder paste soldering, and physical contact. This is not limited herein. Furthermore, the entire area of ​​the connection structure is connected to the serial connection member. This increases the connection area, which helps improve connection stability. It is understood that in other embodiments, a partial area of ​​the connection structure can also be connected to the serial connection member. Furthermore, the serial connection member includes at least one of a soldering ribbon and a conductive wire. This article uses the serial connection member as an example of a soldering ribbon.

[0045] Specifically, the connection structure includes at least one of a pad and a gate line segment.

[0046] Specifically, the number of the connection structures may be 2, 3, 4 or other numbers, which are not limited here.

[0047] See also Figure 1 The second polarity fine grid 20 includes a first fine grid 21 and a second fine grid 22, both located between the end connection block 51 and the first edge 1011. In the first direction, the spacing w1 between the first fine grid 21 and the first main grid 31 is greater than the spacing w2 between the second fine grid 22 and the first main grid 31. This allows for a greater spacing between some of the opposite polarity fine grids between the end connection block 51 and the first edge 1011 and the first main grid 31, leaving space for the head of a serial connector connected to the end connection block 51 and located between the end connection block 51 and the first edge 1011. This allows the head of the serial connector to be further away from the fine grids of different polarity, reducing the risk of short circuits caused by contact between the head of the serial connector and the fine grids of different polarity.

[0048] Specifically, the spacing w1 between the first fine gate 21 and the first main gate 31 refers to the spacing from the first fine gate 21 to the first main gate 31 in the first direction. The spacing w2 between the second fine gate 22 and the first main gate 31 refers to the spacing from the second fine gate 22 to the first main gate 31 in the first direction.

[0049] See also Figure 1 In some embodiments, the difference between the spacing w1 between the first fine grid 21 and the first main grid 31 and the spacing w2 between the second fine grid 22 and the first main grid 31 is 0.1 mm to 0.8 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0050] In this way, the difference between the spacing w1 between the first fine gate 21 and the first main gate 31 and the spacing w2 between the second fine gate 22 and the first main gate 31 is within an appropriate range. This can avoid the situation where the head of the series component is too close to the fine gate of non-corresponding polarity, which may lead to a short circuit, and can also avoid the situation where the area without the second fine gate 22 is too large, which may lead to a poor carrier collection effect.

[0051] Specifically, the spacing w1 between the first fine gate 21 and the first main gate 31 is 0.4 mm to 1 mm. Examples include 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm. This ensures that the spacing w1 between the first fine gate 21 and the first main gate 31 is within an appropriate range, avoiding the risk of short circuits caused by a too small spacing, which may result in a close distance to the series connection, and the risk of poor carrier collection caused by a too large spacing. In this embodiment, the spacing w1 between the first fine gate 21 and the first main gate 31 is 0.7 mm.

[0052] Specifically, the spacing w2 between the second fine grid 22 and the first main grid 31 is 0.2 mm to 0.5 mm. This ensures that the spacing w2 between the second fine grid 22 and the first main grid 31 is within an appropriate range, avoiding the risk of short circuits caused by a too small spacing, which may result in a close distance to the series connection, and the risk of poor carrier collection caused by a too large spacing. In this embodiment, the spacing w2 between the second fine grid 22 and the first main grid 31 is 0.35 mm.

[0053] See also Figure 1 In some embodiments, the back contact cell 100 satisfies the following formula: 0.2≤A / B≤0.9; A is the number of the first fine gates 21 , and B is the number of the second polarity fine gates 20 between the end connection block 51 and the first edge 1011 .

[0054] In this way, the ratio of the number of the first fine gate 21 to the second polarity fine gate 20 between the end connecting block 51 and the first edge 1011 is within an appropriate range, which can avoid the situation where the ratio is too small, resulting in too small a proportion of the second polarity fine gate 20 with a larger distance to the first main grid 31, and a greater risk of short circuit caused by contact with the head of the series component; and can also avoid the situation where the ratio is too large, resulting in too large a proportion of the second polarity fine gate 20 with a larger distance to the first main grid 31, and a poor effect of collecting carriers.

[0055] Specifically, the value of A / B is, for example, 0.2, 0.3, 0.4, 0.44, 0.5, 0.6, 0.7, 0.8, or 0.9. Figure 1 In the example, the number A of the first fine gates 21 is 4, the number B of the second polarity fine gates 20 between the end connection block 51 and the first edge 1011 is 9, and the value of A / B is 0.44.

[0056] Specifically, the number of the first fine gates 21 ranges from 1 to 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. This can avoid the situation where too many first fine gates 21 with large spacing from the first main gate 31 lead to poor carrier collection.

[0057] Specifically, the number of the second fine gates 22 ranges from 1 to 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. This can avoid a high risk of short circuit caused by an excessive number of second fine gates 22 having a small spacing from the first main gate 31.

[0058] Specifically, the number of the second polarity fine grids 20 between the end connection block 51 and the first edge 1011 is 2-20, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

[0059] See also Figure 1 In some embodiments, there are multiple first fine grids 21, which are arranged sequentially along the second direction, and a distance d between the first and last first fine grids 21 is 1 mm to 3 mm, for example, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.42 mm, 2.5 mm, 2.8 mm, or 3 mm.

[0060] In this way, the spacing d between the first fine gate 21 and the last fine gate 21 is within an appropriate range, which can avoid the situation where the first fine gate 21 with a larger spacing to the first main grid 31 is smaller due to too small a spacing, less space left for the head of the series component, and a greater risk of short circuit caused by the head of the series component contacting the fine gate with non-corresponding polarity. It can also avoid the situation where the first fine gate 21 with a larger spacing to the first main grid 31 is larger due to too large a spacing, and the effect of collecting carriers is poor.

[0061] See also Figure 1 、 Figure 2 and Figure 3 In some embodiments, the silicon substrate 101 includes a second edge 1012 extending along the second direction, the first bus gate 31 includes an edge bus gate 311, and the edge bus gate 311 is the first bus gate 31 closest to the second edge 1012; the second polarity fine gate 20 includes a third fine gate 23 and a fourth fine gate 24, the third fine gate 23 is located between the edge bus gate 311 and the second edge 1012, and the fourth fine gate 24 is located between the edge bus gate 311 and the first edge 1011; The back contact battery 100 includes a second main grid 41 and a first connecting grid 61. The second main grid 41 connects the second polarity fine grid 20 and is separated from the first polarity fine grid 10. The first connecting grid 61 is located between the edge main grid 311 and the second edge 1012, connects several third fine grids 23, and is connected to the second main grid 41 through the fourth fine grid 24.

[0062] In this way, the first connecting gate 61 is used to connect several third fine gates 23 located between the edge main gate 311 and the second edge 1012, and is connected to the second main gate 41 via the fourth fine gate 24. This allows the several third fine gates 23 to collect carriers of one polarity between the edge main gate 311 and the second edge 1012, and allows the current collected by the several third fine gates 23 located between the edge main gate 311 and the second edge 1012 to be converged to the second main gate 41, thereby improving the carrier collection effect and facilitating improved current collection efficiency and photoelectric conversion efficiency. Furthermore, to prevent the edge main gate 311 from disconnecting, the distance between the second polarity fine gate 20 and the series connection component can be increased, reducing the risk of short circuits.

[0063] Specifically, the edge busbar 311 is the first busbar 31 closest to the second edge 1012, meaning that there is no other first busbar 31 between the edge busbar 311 and the second edge 1012. However, this does not necessarily mean that there is no other busbar other than the first busbar 31 between the edge busbar 311 and the second edge 1012.

[0064] Specifically, the second main gate 41 is connected to the second polarity fine gate 20 and is spaced apart from the first polarity fine gate 10 , which means that the second main gate 41 is the second polarity main gate 40 .

[0065] Specifically, the first connection gate 61 may pass through the passivation layer to connect to the doped layer. The first connection gate 61 may also be located on the side of the passivation layer away from the doped layer. That is, the first connection gate 61 may be a fine gate or not.

[0066] Specifically, the first connection gate 61 may extend from the outermost third thin gate 23 among the plurality of third thin gates 23 , or may contact the outermost third thin gate 23 among the plurality of third thin gates 23 but not extend therefrom.

[0067] Specifically, the first connection gate 61 may extend from the fourth thin gate 24 , or may contact the fourth thin gate 24 but not extend therefrom.

[0068] Specifically, the width of the first connecting gate 61 can be greater than the width of the second polarity fine gate 20, but smaller than the width of the second main gate 41. This allows the width of the first connecting gate 61 to be within an appropriate range, thereby avoiding the poor conduction effect caused by a smaller width and the waste of slurry and increased costs caused by a larger width.

[0069] See also Figure 1 、 Figure 2 and Figure 3 In some embodiments, the connection structure includes a non-end connection block 52, which is located on the side of the end connection block 51 away from the first edge 1011; the back contact battery 100 includes a fifth fine grid 25, a sixth fine grid 26 and a second connection grid 62, the fifth fine grid 25 is located between the non-end connection block 52 and the second edge 1012, and the sixth fine grid 26 is located between the non-end connection block 52 and the adjacent connection structure in the second direction; the second connection grid 62 is located between the non-end connection block 52 and the second edge 1012, connects several fifth fine grids 25, and is connected to the second main grid 41 through the sixth fine grid 26.

[0070] In this way, the second connecting gate 62 is used to connect several fifth fine gates 25 located between the non-end connecting block 52 and the second edge 1012, and is connected to the second main gate 41 through the sixth fine gate 26. The several fifth fine gates 25 can be used to collect carriers of a certain polarity between the non-end connecting block 52 and the second edge 1012, and the current collected by the several fifth fine gates 25 located between the non-end connecting block 52 and the second edge 1012 can be collected to the second main gate 41, so that the effect of collecting carriers is better, which is conducive to improving the current collection efficiency and photoelectric conversion efficiency.

[0071] Specifically, the second connection gate 62 may pass through the passivation layer to connect to the doped layer. The second connection gate 62 may also be located on the side of the passivation layer away from the doped layer. That is, the second connection gate 62 may be a fine gate or not.

[0072] Specifically, the second connection gate 62 may extend from the outermost fifth thin gate 25 among the plurality of fifth thin gates 25 , or may contact the outermost fifth thin gate 25 among the plurality of fifth thin gates 25 but not extend therefrom.

[0073] Specifically, the second connection gate 62 may extend from the sixth thin gate 26 , or may contact the sixth thin gate 26 but not extend therefrom.

[0074] Specifically, the width of the second connecting gate 62 can be greater than the width of the second polarity fine gate 20, but smaller than the width of the second main gate 41. This allows the width of the second connecting gate 62 to be within an appropriate range, thereby avoiding the poor conduction effect caused by a smaller width and the waste of slurry and increased costs caused by a larger width.

[0075] See also Figure 3 In some embodiments, the length L1 of the first connection gate 61 is greater than the length L2 of the second connection gate 62 .

[0076] As such, the length of the first connecting grid 61 between the edge busbar 311 and the second edge 1012 is greater than the length of the second connecting grid 62 between the non-end connecting block 52 and the second edge 1012, allowing the length of the connecting grids to adapt to the surrounding structure. The larger length of the first connecting grid 61 allows for better connection between the fourth fine grid 24 and the plurality of third fine grids 23. Furthermore, this leaves sufficient space for the ribbon head, reducing the risk of short circuits caused by contact between the ribbon head and fine grids of inappropriate polarity.

[0077] Specifically, the length L1 of the first connecting grid 61 is 3 mm to 10 mm, for example, 3 mm, 4 mm, 5 mm, 5.64 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. This ensures that the length L1 of the first connecting grid 61 is within an appropriate range, avoiding difficulties in connecting the third and fourth thin grids 23 and 24 due to a too short length, and also avoiding contact with the first polarity thin grid 10 and a high risk of short circuit due to an excessive length.

[0078] Specifically, the length L2 of the second connecting grid 62 is 0.5 mm to 2.5 mm, for example, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 1.61 mm, 1.8 mm, 2 mm, 2.2 mm, or 2.5 mm. This ensures that the length L2 of the second connecting grid 62 is within an appropriate range, avoiding difficulties in connecting the fifth and sixth thin grids 25 and 26 due to a too short length, and also avoiding contact with the first polarity thin grid 10 and a high risk of short circuit due to an excessive length.

[0079] See also Figure 3 In some embodiments, the back contact cell 100 satisfies the following formula: 1.1≤C / D≤4; Wherein, C is the number of the second polarity fine gates 20 connected to the first connection gate 61 , and B is the number of the second polarity fine gates 20 connected to the second connection gate 62 .

[0080] In this way, the ratio of the number of second polarity fine gates 20 connected to the first connecting gate 61 to the number of second polarity fine gates 20 connected to the second connecting gate 62 is within an appropriate range, which can avoid the situation where the number of second polarity fine gates 20 connected to the first connecting gate 61 is too small, and the effect of collecting corresponding polarity carriers at the position where the first connecting gate 61 is located is poor. It can also avoid the situation where the number of second polarity fine gates 20 connected to the first connecting gate 61 is too large, and the effect of collecting another polarity carriers at the first connecting gate 61 is poor.

[0081] Specifically, the value of C / D is, for example, 1.1, 1.2, 1.5, 1.8, 2, 2.67, 2.8, 3, 3.5, or 4. Figure 3In the example of FIG, the number C of the second polarity fine gates 20 connected to the first connection gate 61 is 8, the number D of the second polarity fine gates 20 connected to the second connection gate 62 is 3, and C / D is 2.67.

[0082] Specifically, the number C of the second polarity fine gates 20 connected to the first connection gate 61 is 6-10, for example, 6, 7, 8, 9, or 10.

[0083] Specifically, the number D of the second polarity fine gates 20 connected to the second connection gate 62 is 2-5, for example, 2, 3, 4, or 5.

[0084] The battery assembly of the embodiment of the present application includes any of the above-mentioned back-contact batteries 100.

[0085] In the battery assembly of the embodiment of the present application, since in the back-contact battery 100, the first fine grid 21 and the second fine grid 22 are both located between the end connection block 51 and the first edge 1011 and the spacing between the first fine grid 21 and the first main grid 31 is greater than the spacing between the second fine grid 22 and the first main grid 31, the spacing between some of the opposite-sex fine grids between the end connection block 51 and the first edge 1011 and the first main grid 31 is larger, leaving space for the head of the serial connector connected to the end connection block 51 and located between the end connection block 51 and the first edge 1011, so that the distance between the head of the serial connector and the fine grids of non-corresponding polarity is farther, reducing the risk of short circuit caused by the head of the serial connector contacting the fine grids of non-corresponding polarity.

[0086] In this embodiment, multiple back-contact cells 100 in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series bus output of the current. For example, the series connection of the battery cells can be realized by setting welding strips (bus bars, interconnecting bars), conductive back plates, etc.

[0087] It is understood that in such an embodiment, the battery assembly may further include a metal frame, a backsheet, photovoltaic glass, and an adhesive film. The adhesive film may be placed between the front and back surfaces of the back-contact battery 100, the photovoltaic glass, adjacent cells, and the like. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film may be EVA or POE. The specific choice may be based on actual conditions and is not limited here.

[0088] Photovoltaic glass can cover the adhesive film on the front surface of the back-contact cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, ultra-clear glass can have a light transmittance of over 92%, protecting the back-contact cell 100 while minimizing the impact on its efficiency. The adhesive film can also bond the photovoltaic glass and back-contact cell 100 together, providing sealing, insulation, and waterproofing for the back-contact cell 100.

[0089] A backsheet can be attached to the film on the back of the back-contact cell 100. The backsheet protects and supports the back-contact cell 100, offering reliable insulation, water resistance, and aging resistance. A variety of backsheet options are available, typically including tempered glass, organic glass, and aluminum alloy TPT composite film. The specific configuration depends on the specific situation and is not limited here. The backsheet, back-contact cell 100, film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the primary external support structure for the entire battery assembly and provides stable support and installation for the battery assembly. For example, the metal frame can be used to mount the battery assembly in the desired location.

[0090] The photovoltaic system of the embodiment of the present application includes the above-mentioned battery assembly.

[0091] In the photovoltaic system of the embodiment of the present application, since in the back-contact cell 100 of the battery assembly, the first fine grid 21 and the second fine grid 22 are both located between the end connection block 51 and the first edge 1011 and the spacing between the first fine grid 21 and the first main grid 31 is greater than the spacing between the second fine grid 22 and the first main grid 31, the spacing between some of the opposite-sex fine grids between the end connection block 51 and the first edge 1011 and the first main grid 31 is larger, leaving space for the head of the serial connector connected to the end connection block 51 and located between the end connection block 51 and the first edge 1011, so that the distance between the head of the serial connector and the fine grids of non-corresponding polarity is farther, reducing the risk of short circuit caused by the head of the serial connector contacting the fine grids of non-corresponding polarity.

[0092] In this embodiment, the photovoltaic system can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array can be an array combination of multiple battery modules. For example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter to be converted into the alternating current required by the mains power grid and then connected to the mains power network to achieve solar power supply.

[0093] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0094] In addition, the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A back contact battery, characterized in that: include: A silicon substrate comprising a first edge extending along a first direction; A plurality of first polarity fine gates and a plurality of second polarity fine gates spaced apart from each other are provided on the silicon substrate, extend along the first direction, and are arranged along a second direction, wherein the second direction intersects the first direction; a first main gate, provided on the silicon substrate, extending along the second direction, connecting the first polarity fine gate and spaced apart from the second polarity fine gate; a plurality of connection structures arranged along the second direction and provided on the first main grid for connecting series components, including an end connection block, wherein the end connection block is the connection structure closest to the first edge; The second polarity fine grid includes a first fine grid and a second fine grid, both of which are located between a boundary line of the end connection block close to the first edge and the first edge, and the number of the first fine grids is multiple, and the multiple first fine grids are arranged in sequence along the second direction; In the first direction, the distance between the first fine gate and the first main gate is greater than the distance between the second fine gate and the first main gate; The silicon substrate includes a second edge extending along the second direction, the first main gate includes an edge main gate, and the edge main gate is the first main gate closest to the second edge; the second polarity fine gate includes a third fine gate and a fourth fine gate, the third fine gate is located between the edge main gate and the second edge, and the fourth fine gate is located between the edge main gate and the first edge; The back contact battery includes a second main grid and a first connecting grid, wherein the second main grid is connected to the second polarity fine grid and is spaced apart from the first polarity fine grid; the first connecting grid is located between the edge main grid and the second edge, connects several of the third fine grids, and is connected to the second main grid through the fourth fine grid.

2. The back contact battery according to claim 1, characterized in that The difference between the spacing between the first fine grid and the first main grid and the spacing between the second fine grid and the first main grid is 0.1 mm to 0.8 mm.

3. The back contact battery according to claim 1, characterized in that The back contact cell satisfies the following formula: 0.2≤A / B≤0.9; Wherein, A is the number of the first fine grids, and B is the number of the second polarity fine grids between the end connecting block and the first edge.

4. The back contact battery according to claim 1, characterized in that The distance between the first first fine grid and the last first fine grid is 1 mm-3 mm.

5. The back contact battery according to claim 1, characterized in that The connection structure includes a non-end connection block, and the non-end connection block is located on a side of the end connection block away from the first edge; The back-contact battery includes a fifth fine grid, a sixth fine grid and a second connecting grid. The fifth fine grid is located between the non-end connecting block and the second edge, and the sixth fine grid is located between the non-end connecting block and the connecting structure adjacent in the second direction; the second connecting grid is located between the non-end connecting block and the second edge, connects several of the fifth fine grids, and is connected to the second main grid through the sixth fine grid.

6. The back contact battery according to claim 5, characterized in that The length of the first connection gate is greater than the length of the second connection gate.

7. The back contact battery according to claim 5, characterized in that The back contact cell satisfies the following formula: 1.1≤C / D≤4; Wherein, C is the number of the second polarity fine gates connected to the first connecting gate, and B is the number of the second polarity fine gates connected to the second connecting gate.

8. A battery assembly, characterized in that: A back contact battery comprising the battery according to any one of claims 1 to 7.

9. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 8.

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