A back-contact battery, battery module and photovoltaic system

Abstract

This application relates to the field of solar cell technology and provides a back-contact cell, a cell module, and a photovoltaic system. The back-contact cell includes: a silicon substrate, including a first edge extending along a first direction; a plurality of first polar grids and a plurality of second polar grids spaced apart from each other, disposed on the silicon substrate, extending along the first direction and arranged along a second direction, the second direction intersecting the first direction; a first main grid, disposed on the silicon substrate, extending along the second direction, connecting the first polar grids and spaced apart from the second polar grids; a plurality of connection structures arranged along the second direction, disposed on the first main grid, for connecting series members, including end connection blocks, the end connection blocks being the connection structures closest to the first edge; the second polar grids include first grids and second grids, both located between the end connection blocks and the first edge; in the first direction, the spacing between the first grids and the first main grid is greater than the spacing between the second grids and the first main grid.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to a back contact cell, a cell module, and a photovoltaic system. Background Technology

[0002] Solar cell power generation is a sustainable and clean energy source that converts sunlight into electrical energy using the photovoltaic effect of a semiconductor PN junction. A cell with grid lines of both polarities located on the same side of the cell is a back-contact cell. Typically, electrical connectors such as solder ribbons or 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, forming a cell string. Insulating adhesive is used to isolate the solder ribbons from the grid lines of mismatched polarities. However, the tips of the electrical connectors can easily come into contact with grid lines of mismatched polarities, causing the cell string to short-circuit.

[0003] Therefore, how to reduce the risk of short circuits caused by mismatched grid lines at the head of electrical connectors has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides a back-contact battery, battery module, and photovoltaic system, aiming to solve the problem of how to reduce the short-circuit risk caused by grid lines with mismatched head contact polarities of electrical connectors.

[0005] The back contact battery provided in this application includes:

[0006] A silicon substrate, including a first edge extending along a first direction;

[0007] A plurality of first polarity fine gates and a plurality of second polarity fine gates spaced apart from each other are disposed on the silicon substrate, extending along the first direction and arranged along the second direction, the second direction intersecting the first direction;

[0008] A first main gate is disposed on the silicon substrate, extends along the second direction, connects to the first polar fine gate and is spaced apart from the second polar fine gate;

[0009] A plurality of connection structures are arranged along the second direction and disposed on the first main grid for connecting the serial connectors, including end connection blocks, wherein the end connection blocks are the connection structures closest to the first edge;

[0010] The second polar fine gate includes a first fine gate and a second fine gate, both located between the end connecting 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.

[0011] Specifically, the difference between the spacing between the first fine gate and the first main gate and the spacing between the second fine gate and the first main gate is 0.1mm-0.8mm.

[0012] Specifically, the back contact battery satisfies the following formula:

[0013] 0.2 ≤ A / B ≤ 0.9;

[0014] Where A is the number of the first fine grids, and B is the number of the second polar fine grids between the end connecting block and the first edge.

[0015] Specifically, there are multiple first fine gates, which are arranged sequentially along the second direction, and the distance between the first and last first fine gates is 1mm-3mm.

[0016] Specifically, the silicon substrate includes a second edge extending along the second direction, the first main gate includes an edge main gate, the edge main gate being the first main gate closest to the second edge; the second polar fine gate includes a third fine gate and a fourth fine gate, the third fine gate being located between the edge main gate and the second edge, and the fourth fine gate being located between the edge main gate and the first edge;

[0017] The back contact battery includes a second main grid and a first connecting grid. The second main grid is connected to the second polar fine grid and spaced apart from the first polar fine grid. The first connecting grid is located between the edge main grid and the second edge, connects to a plurality of the third fine grids, and is connected to the second main grid through the fourth fine grid.

[0018] Specifically, the connection structure includes a non-end connection block located on the side of the end connection block opposite to the first edge;

[0019] 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. 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 a plurality of the fifth fine grids, and is connected to the second main grid through the sixth fine grid.

[0020] Specifically, the length of the first connecting gate is greater than the length of the second connecting gate.

[0021] Specifically, the back contact battery satisfies the following formula:

[0022] 1.1≤C / D≤4;

[0023] Wherein, C is the number of second polar fine gates connected to the first connecting gate, and B is the number of second polar fine gates connected to the second connecting gate.

[0024] The battery assembly provided in this application includes the back contact battery of any of the above.

[0025] The photovoltaic system provided in this application includes the battery modules described above.

[0026] In the back-contact battery, battery module, and photovoltaic system of this application embodiment, since both the first fine grid and the second fine grid are located between the end connecting block and the first edge, and the distance between the first fine grid and the first main grid is greater than the distance between the second fine grid and the first main grid, the distance between the partial non-polar fine grids between the end connecting block and the first edge and the first main grid is relatively large. This provides space for the head of the serial connector connected to the end connecting block and located between the end connecting block and the first edge, making the distance between the head of the serial connector and the fine grid with non-corresponding polarity greater, reducing the risk of short circuit caused by the head of the serial connector contacting the fine grid with non-corresponding polarity. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a partial structure of a back contact battery according to an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the structure of a back contact battery according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of a partial structure of a back contact battery according to an embodiment of this application;

[0030] Explanation of key component symbols:

[0031] The back contact battery 100, silicon substrate 101, first edge 1011, second edge 1012, first polar fine grid 10, second polar 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 polar main grid 30, first main grid 31, edge main grid 311, second polar main grid 40, second main grid 41, end connection block 51, non-end connection block 52, first connection grid 61, second connection grid 62;

[0032] 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 and last first fine gates, the length L1 of the first connecting gate, and the length L2 of the second connecting gate. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0034] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0039] Please see Figure 1 and Figure 2 The back contact battery 100 of this application embodiment includes:

[0040] The silicon substrate 101 includes a first edge 1011 extending along a first direction;

[0041] A plurality of first polar fine gates 10 and a plurality of second polar fine gates 20 spaced apart from each other 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;

[0042] The first main gate 31 is disposed on the silicon substrate 101, extends along the second direction, connects to the first polar fine gate 10 and is spaced apart from the second polar fine gate 20;

[0043] Several connection structures are arranged along the second direction and disposed on the first main grid 31 for connecting the serial connectors, including an end connection block 51, which is the connection structure closest to the first edge 1011.

[0044] The second polar fine gate 20 includes a first fine gate 21 and a second fine gate 22, both located between the end connecting block 51 and the first edge 1011; in the first direction, the distance w1 between the first fine gate 21 and the first main gate 31 is greater than the distance w2 between the second fine gate 22 and the first main gate 31.

[0045] In the back contact battery 100 of this application embodiment, since both the first fine grid 21 and the second fine grid 22 are located between the end connecting block 51 and the first edge 1011, and the distance between the first fine grid 21 and the first main grid 31 is greater than the distance between the second fine grid 22 and the first main grid 31, the distance between the partial non-polar fine grids between the end connecting block 51 and the first edge 1011 and the first main grid 31 is relatively large. This provides space for the head of the connector connected to the end connecting block 51 and located between the end connecting block 51 and the first edge 1011, so that the distance between the head of the connector and the fine grids with different polarities is relatively large, reducing the risk of short circuit caused by the head of the connector contacting the fine grids with different polarities.

[0046] Specifically, the back contact battery 100 can be a sliced ​​battery formed by cutting a whole battery cell. For example, Figure 2 A half-cell battery is formed by cutting a whole cell in half. The back contact cell 100 can also be a whole cell that has not been cut. The whole back contact cell 100 may include slicing grooves along which the whole cell can be cut to obtain... Figure 2 The sliced ​​battery shown. The entire back contact battery 100 can be asymmetrical along the slice groove, or it can be symmetrical along the slice groove.

[0047] Specifically, the silicon substrate 101 may include a silicon substrate, a first polar doped layer, a second polar doped layer, and a dielectric film layer. Further, the silicon substrate may be a P-type silicon substrate or an N-type silicon substrate; it may be a monocrystalline silicon substrate or a polycrystalline silicon substrate. The specific form of the silicon substrate is not limited here. Further, the first polar doped layer and the second polar doped layer are disposed on the silicon substrate. The first polar doped layer and the second polar doped layer have different doping polarities. The two doped layers can be formed by diffusion into the silicon substrate or by deposition of films on the silicon substrate. It can be understood that, in the thickness direction of the back contact cell 100, the first polar doped layer is stacked on the silicon substrate, and the second polar doped layer is stacked on the silicon substrate. On a plane perpendicular to the thickness direction of the back contact cell 100, the first polar doped layer and the second polar doped layer are distributed in regions, corresponding to the first polar doped region and the second polar doped region, respectively.

[0048] Furthermore, the dielectric film can cover the first polar doped layer and the second polar doped layer, with the first polar fine gate 10 penetrating the dielectric film to contact the first polar doped layer, and the second polar fine gate 20 penetrating the dielectric film to contact the second polar doped layer. In this way, the dielectric film achieves electrical isolation between the first polar doped layer and the second polar doped layer, while also reducing light reflection and recombination. The dielectric film can also be disposed between at least one pair of adjacent first polar doped regions and second polar doped regions, electrically isolating the first polar doped region and the second polar doped region.

[0049] Specifically, the first polar fine gate 10 and the second polar fine gate 20 may be distributed over the entire area of ​​the silicon substrate 101; or the first polar fine gate 10 and the second polar fine gate 20 may be distributed over a portion of the silicon substrate 101.

[0050] Specifically, the first polar fine gate 10 and the second polar fine gate 20 have different polarities. The first polar fine gate 10 corresponds to the first polar doped layer and the first polar doped region. The second polar fine gate 20 corresponds to the second polar doped layer and the second polar doped region.

[0051] Specifically, the number of first polar fine gates 10 can be 1, 2, 3, 4, or other numbers. The number of second polar fine gates 20 can be 1, 2, 3, 4, or other numbers. No limitation is made here. The number of first polar fine gates 10 and the number of second polar fine gates 20 can be the same or different.

[0052] Specifically, the first polar fine gate 10 and the second polar fine gate 20 extend along the first direction, meaning that the overall extension direction is the first direction. This does not represent a limitation on the specific shape of the first polar fine gate 10 and the second polar fine gate 20. In this embodiment, the first polar fine gate 10 and the second polar fine gate 20 are linear, and the extension direction of the first polar fine gate 10 and the second polar fine gate 20, that is, the first direction, is the length direction of the first polar fine gate 10 and the second polar fine gate 20. In other embodiments, the first polar fine gate 10 may be wavy, zigzag, or other shapes. The second polar fine gate 20 may be wavy, zigzag, or other shapes.

[0053] Specifically, the first polar fine gate 10 and the second polar fine gate 20 are arranged along the second direction, which can be alternating or non-alternating along the second direction; they can be arranged at equal intervals or at unequal intervals along the second direction. No limitation is made here.

[0054] Specifically, the first polar fine gate 10 and the second polar fine gate 20 are spaced apart, meaning that a gap is formed between adjacent first polar fine gates 10 and second polar fine gates 20. The gap can be filled with an insulating element or it can be an air gap.

[0055] Please see Figure 2 The back contact battery 100 may include a plurality of first polarity main gates 30 and a plurality of second polarity main gates 40 spaced apart from each other, disposed on a silicon substrate 101, extending along a second direction and arranged along a first direction. The first polarity main gates 30 are connected to a plurality of first polarity fine gates 10 and spaced apart from the second polarity fine gates 20. The second polarity main gates 40 are connected to a plurality of second polarity fine gates 20 and spaced apart from the first polarity fine gates 10.

[0056] Specifically, the first polar main gate 30 and the second polar main gate 40 extend along the second direction, meaning that the overall extension direction is the second direction. This does not represent a limitation on the specific shape of the first polar main gate 30 and the second polar main gate 40. In this embodiment, the first polar main gate 30 and the second polar main gate 40 are straight lines, and the extension direction of the first polar main gate 30 and the second polar main gate 40, that is, the second direction, is the length direction of the first polar main gate 30 and the second polar main gate 40. In other embodiments, the first polar main gate 30 may be wavy, zigzag, or other shapes. The second polar main gate 40 may be wavy, zigzag, or other shapes.

[0057] Specifically, the first polarity main gate 30 and the second polarity main gate 40 are arranged along the first direction, which can be alternating or non-alternating along the first direction; they can be arranged at equal intervals or at unequal intervals along the first direction. No limitation is made here.

[0058] Specifically, the first polarity main gate 30 and the second polarity main gate 40 are spaced apart, meaning that a gap is formed between adjacent first polarity main gates 30 and second polarity main gates 40. The gap can be filled with an insulating material or it can be an air gap.

[0059] Specifically, the first polarity gate 30 includes a first gate 31, and the second polarity gate 40 includes a second gate 41.

[0060] exist Figure 2 In the example, the first polar main gate 30 is the first main gate 31. That is, for each first polar main gate 30, there is a portion of the distance between the second polar fine gate 20 and the first polar main gate 30 between the corresponding end connecting block 51 and the first edge 1011 that is greater than the distance between the remaining second polar fine gate 20 and the first polar main gate 30.

[0061] It is understandable that in other examples, some of the first polarity gates 30 may be the first gates 31, while the remaining first polarity gates 30 may not satisfy the characteristics of the first gates 31.

[0062] exist Figure 2 In the example, for each second polarity main gate 40, between the corresponding end connecting block 51 and the first edge 1011, there exists a portion of the distance between the first polarity fine gate 10 and the second polarity main gate 40 that is greater than the distance between the remaining first polarity fine gate 10 and the second polarity main gate 40. For an explanation and description of this portion, please refer to the explanation and description of the first main gate 31; to avoid redundancy, it will not be repeated here.

[0063] It is understandable that in other examples, it is also possible that for some of the second polar main gates 40, between the corresponding end connecting block 51 and the first edge 1011, the distance between a portion of the first polar fine gates 10 and the second polar main gate 40 is greater than the distance between the remaining first polar fine gates 10 and the second polar main gate 40.

[0064] Please see Figure 2 The back contact battery 100 includes several connection structures arranged along the second direction and located on the first main grid 31 for connecting serial members. The connection structures include an end connection block 51, which is the connection structure closest to the first edge 1011.

[0065] Specifically, the connecting structure and the serial connector can be electrically connected through at least one of the following methods: conductive adhesive bonding, direct soldering, solder paste soldering, or physical contact. No limitation is made here. Furthermore, the entire area of ​​the connecting structure is connected to the serial connector. This results in a larger connection area, which is beneficial for improving connection stability. It is understood that in other embodiments, only a portion of the connecting structure may be connected to the serial connector. Further, the serial connector includes at least one of solder strips and conductive wires. This document uses solder strips as an example for illustrating the serial connector.

[0066] Specifically, the connection structure includes at least one of pads and gate segments.

[0067] Specifically, the number of connection structures can be 2, 3, 4, or other numbers. No limitation is made here.

[0068] Please see Figure 1 The second polarity fine gate 20 includes a first fine gate 21 and a second fine gate 22, both located between the end connecting block 51 and the first edge 1011. In the first direction, the distance w1 between the first fine gate 21 and the first main gate 31 is greater than the distance w2 between the second fine gate 22 and the first main gate 31. This results in a larger distance between the portion of the non-polarity fine gates between the end connecting block 51 and the first edge 1011 and the first main gate 31, providing space for the head of the connector connected to the end connecting block 51 and located between the end connecting block 51 and the first edge 1011. This ensures that the head of the connector is farther from the fine gates with different polarities, reducing the risk of short circuits caused by contact between the head of the connector and the fine gates with different polarities.

[0069] Specifically, the distance w1 between the first fine gate 21 and the first main gate 31 refers to the distance between the first fine gate 21 and the first main gate 31 in the first direction. The distance w2 between the second fine gate 22 and the first main gate 31 refers to the distance between the second fine gate 22 and the first main gate 31 in the first direction.

[0070] Please see Figure 1 In some embodiments, 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 0.1mm-0.8mm. For example, it is 0.1mm, 0.2mm, 0.3mm, 0.35mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, or 0.8mm.

[0071] 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 a suitable range. This avoids the situation where the head of the connector is too close to the fine gate with the opposite polarity due to the difference being too small, which could easily cause a short circuit. It also avoids the situation where the area without the second fine gate 22 is too large due to the difference being too large, which could result in a poor carrier collection effect.

[0072] Specifically, the spacing w1 between the first fine gate 21 and the first main gate 31 is 0.4mm-1mm. For example, it is 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm. This ensures the spacing w1 is within a suitable range, avoiding the risk of short circuits due to excessively small spacing (too close to the connector) and excessively large spacing (too large an area without the first fine gate 21, resulting in poor carrier collection). In this embodiment, the spacing w1 between the first fine gate 21 and the first main gate 31 is 0.7mm.

[0073] Specifically, the spacing w2 between the second fine gate 22 and the first main gate 31 is 0.2mm-0.5mm. This ensures the spacing w2 is within a suitable range, avoiding both excessively small spacing (leading to close proximity to the connector and a higher risk of short circuits) and excessively large spacing (resulting in a larger area without the second fine gate 22 and poorer carrier collection). In this embodiment, the spacing w2 between the second fine gate 22 and the first main gate 31 is 0.35mm.

[0074] Please see Figure 1 In some embodiments, the back contact battery 100 satisfies the following formula:

[0075] 0.2 ≤ A / B ≤ 0.9;

[0076] Where A represents the number of first fine grids 21, and B represents the number of second polar fine grids 20 between the end connecting block 51 and the first edge 1011.

[0077] In this way, the ratio of the number of second polar fine gates 20 between the first fine gate 21 and the end connecting block 51 and the first edge 1011 is within a suitable range. This avoids the situation where the ratio is too small, resulting in a small proportion of second polar fine gates 20 with a large distance to the first main gate 31, which could lead to a high risk of short circuits caused by contact with the head of the connector. It also avoids the situation where the ratio is too large, resulting in a large proportion of second polar fine gates 20 with a large distance to the first main gate 31, which could lead to poor carrier collection.

[0078] Specifically, the values ​​of A / B are, for example, 0.2, 0.3, 0.4, 0.44, 0.5, 0.6, 0.7, 0.8, and 0.9. In Figure 1 In the example, the number A of the first fine grid 21 is 4, the number B of the second polar fine grid 20 between the end connecting block 51 and the first edge 1011 is 9, and the value of A / B is 0.44.

[0079] 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, 10. In this way, it can be avoided that an excessive number of first fine gates 21 with a large spacing from the first main gate 31 would result in poor carrier collection efficiency.

[0080] Specifically, the number of second fine gates 22 ranges from 1 to 10. For example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. In this way, an excessive number of second fine gates 22 with small spacing to the first main gate 31 can be avoided, which would lead to a greater risk of short circuit.

[0081] Specifically, the number of second polar fine grids 20 between the end connecting block 51 and the first edge 1011 is 2-20. For example, they are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.

[0082] Please see Figure 1 In some embodiments, there are multiple first fine gates 21, which are arranged sequentially along the second direction, and the distance d between the first and last first fine gates 21 is 1mm-3mm. For example, it is 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.42mm, 2.5mm, 2.8mm, or 3mm.

[0083] In this way, the distance d between the first fine gate 21 and the last fine gate 21 is within a suitable range. This avoids the situation where the distance between the first fine gate 21 and the first main gate 31 is too small, resulting in a small range, less space for the head of the cascaded component, and a greater risk of short circuit caused by the head of the cascaded component contacting the fine gate with a different polarity. It also avoids the situation where the distance between the first fine gate 21 and the first main gate 31 is too large, resulting in a large range and poor carrier collection effect.

[0084] Please see Figure 1 , Figure 2 and Figure 3 In some embodiments, the silicon substrate 101 includes a second edge 1012 extending along a second direction, the first main gate 31 includes an edge main gate 311, the edge main gate 311 being the first main gate 31 closest to the second edge 1012; the second polar fine gate 20 includes a third fine gate 23 and a fourth fine gate 24, the third fine gate 23 being located between the edge main gate 311 and the second edge 1012, and the fourth fine gate 24 being located between the edge main gate 311 and the first edge 1011;

[0085] The back contact battery 100 includes a second main grid 41 and a first connecting grid 61. The second main grid 41 is connected to the second polar fine grid 20 and spaced apart from the first polar fine grid 10. The first connecting grid 61 is located between the edge main grid 311 and the second edge 1012, connects to a plurality of third fine grids 23, and is connected to the second main grid 41 through a fourth fine grid 24.

[0086] Thus, by connecting several third fine gates 23 located between the edge main gate 311 and the second edge 1012 using the first connecting gate 61, and connecting them to the second main gate 41 via the fourth fine gate 24, it is possible to collect one polarity of charge carriers between the edge main gate 311 and the second edge 1012 using the several third fine gates 23. This allows the current collected by the several third fine gates 23 between the edge main gate 311 and the second edge 1012 to converge to the second main gate 41, resulting in better charge carrier collection and improved current collection efficiency and photoelectric conversion efficiency. Furthermore, the second polar fine gate 20 will be disconnected to avoid the edge main gate 311, which can increase the distance between the series connector and the second polar fine gate 20, reducing the risk of short circuits.

[0087] Specifically, the edge main gate 311 is the first main gate 31 closest to the second edge 1012, meaning that there are no other first main gates 31 between the edge main gate 311 and the second edge 1012. However, this does not mean that there are no other main gates besides the first main gate 31 between the edge main gate 311 and the second edge 1012.

[0088] Specifically, the second main gate 41 being connected to the second polar fine gate 20 and spaced apart from the first polar fine gate 10 means that the second main gate 41 is the second polar main gate 40.

[0089] Specifically, the first connection gate 61 can pass through the passivation layer and connect to the doped layer. The first connection gate 61 can also be located on the side of the passivation layer away from the doped layer. That is, the first connection gate 61 can be a fine gate or not.

[0090] Specifically, the first connecting gate 61 can extend from the outermost third fine gate 23 among a plurality of third fine gates 23, or it can contact the outermost third fine gate 23 among a plurality of third fine gates 23 but not extend out.

[0091] Specifically, the first connecting gate 61 can extend from the fourth fine gate 24, or it can contact the fourth fine gate 24 but not extend out.

[0092] Specifically, the width of the first connecting gate 61 can be greater than the width of the second polar fine gate 20, but less than the width of the second main gate 41. This ensures that the width of the first connecting gate 61 is within a suitable range, avoiding poor carrier conduction due to a smaller width, and also avoiding waste of paste and increased costs due to a larger width.

[0093] Please see Figure 1 , Figure 2 and Figure 3 In some embodiments, the connection structure includes a non-end connection block 52 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 being located between the non-end connection block 52 and the second edge 1012, the sixth fine grid 26 being located between the non-end connection block 52 and the connection structure adjacent in the second direction; the second connection grid 62 being located between the non-end connection block 52 and the second edge 1012, connecting a plurality of fifth fine grids 25, and being connected to the second main grid 41 through the sixth fine grid 26.

[0094] Thus, by using the second connecting gate 62 to connect several fifth fine gates 25 located between the non-end connecting blocks 52 and the second edge 1012, and connecting them to the second main gate 41 through the sixth fine gate 26, it is possible to use several fifth fine gates 25 to collect a type of polarity of charge carriers between the non-end connecting blocks 52 and the second edge 1012, and to allow the current collected by the several fifth fine gates 25 located between the non-end connecting blocks 52 and the second edge 1012 to be concentrated in the second main gate 41, resulting in a better effect of collecting charge carriers and improving current collection efficiency and photoelectric conversion efficiency.

[0095] Specifically, the second connection gate 62 can pass through the passivation layer and connect to the doped layer. The second connection gate 62 can also be located on the side of the passivation layer away from the doped layer. That is, the second connection gate 62 can be a fine gate or not.

[0096] Specifically, the second connecting gate 62 may extend from the outermost fifth fine gate 25 among a plurality of fifth fine gates 25, or it may contact the outermost fifth fine gate 25 among a plurality of fifth fine gates 25 but not extend out.

[0097] Specifically, the second connecting gate 62 can extend from the sixth fine gate 26, or it can contact the sixth fine gate 26 but not extend out.

[0098] Specifically, the width of the second connecting gate 62 can be greater than the width of the second polar fine gate 20 but less than the width of the second main gate 41. This ensures that the width of the second connecting gate 62 is within a suitable range, avoiding poor carrier conduction due to a smaller width, and also avoiding waste of paste and increased costs due to a larger width.

[0099] Please see Figure 3 In some embodiments, the length L1 of the first connecting gate 61 is greater than the length L2 of the second connecting gate 62.

[0100] Thus, the length of the first connecting gate 61 between the edge main gate 311 and the second edge 1012 is greater than the length of the second connecting gate 62 between the non-end connecting block 52 and the second edge 1012, making the length of the connecting gate adapt to the surrounding structure. The larger length of the first connecting gate 61 allows for better connection between the fourth fine gate 24 and several third fine gates 23. Moreover, this provides sufficient space for the solder ribbon head, reducing the risk of short circuits caused by contact between the solder ribbon head and fine gates with mismatched polarities.

[0101] Specifically, the length L1 of the first connecting gate 61 is 3mm-10mm. For example, it can be 3mm, 4mm, 5mm, 5.64mm, 6mm, 7mm, 8mm, 9mm, or 10mm. This ensures that the length L1 of the first connecting gate 61 is within a suitable range, avoiding the difficulty in connecting the third fine gate 23 and the fourth fine gate 24 due to an excessively small length, and also avoiding the risk of contact with the first polarity fine gate 10 and a high risk of short circuit due to an excessively large length.

[0102] Specifically, the length L2 of the second connecting gate 62 is 0.5mm-2.5mm. For example, it can be 0.5mm, 0.8mm, 1mm, 1.5mm, 1.61mm, 1.8mm, 2mm, 2.2mm, or 2.5mm. This ensures that the length L2 of the second connecting gate 62 is within a suitable range, avoiding the difficulty in connecting the fifth fine gate 25 and the sixth fine gate 26 due to an excessively small length, and also avoiding the risk of contact with the first polarity fine gate 10 and a high risk of short circuit due to an excessively large length.

[0103] Please see Figure 3 In some embodiments, the back contact battery 100 satisfies the following formula:

[0104] 1.1≤C / D≤4;

[0105] Wherein, C is the number of second polar fine gates 20 connected to the first connecting gate 61, and B is the number of second polar fine gates 20 connected to the second connecting gate 62.

[0106] In this way, the ratio of the number of second polar fine gates 20 connected to the first connecting gate 61 to the number of second polar fine gates 20 connected to the second connecting gate 62 is within a suitable range. This avoids the situation where the ratio is too small, resulting in a small number of second polar fine gates 20 connected to the first connecting gate 61 and poor collection of the corresponding polarity carriers at the location of the first connecting gate 61. It also avoids the situation where the ratio is too large, resulting in a large number of second polar fine gates 20 connected to the first connecting gate 61 and poor collection of the other polarity carriers at the location of the first connecting gate 61.

[0107] Specifically, the C / D values ​​are, for example, 1.1, 1.2, 1.5, 1.8, 2, 2.67, 2.8, 3, 3.5, and 4. In Figure 3 In the example, the number C of second polar fine gates 20 connected to the first connecting gate 61 is 8, the number D of second polar fine gates 20 connected to the second connecting gate 62 is 3, and C / D is 2.67.

[0108] Specifically, the number C of the second polar fine gates 20 connected to the first connecting gate 61 is 6-10. For example, it is 6, 7, 8, 9, or 10.

[0109] Specifically, the number D of the second polar fine gates 20 connected to the second connecting gate 62 is 2-5. For example, 2, 3, 4, 5.

[0110] The battery assembly of this application embodiment includes the back contact battery 100 of any of the above.

[0111] In the battery assembly of this application embodiment, since the first fine grid 21 and the second fine grid 22 in the back contact battery 100 are both located between the end connecting block 51 and the first edge 1011, and the distance between the first fine grid 21 and the first main grid 31 is greater than the distance between the second fine grid 22 and the first main grid 31, the distance between the partial non-polar fine grids between the end connecting block 51 and the first edge 1011 and the first main grid 31 is relatively large. This provides space for the head of the connector connected to the end connecting block 51 and located between the end connecting block 51 and the first edge 1011, so that the distance between the head of the connector and the fine grids with different polarities is relatively large, reducing the risk of short circuit caused by the head of the connector contacting the fine grids with different polarities.

[0112] In this embodiment, multiple back-contact batteries 100 in the battery assembly can be connected in series to form a battery string, thereby realizing the series current collection and output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0113] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back sides of the back contact battery 100, the photovoltaic glass, adjacent battery cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0114] Photovoltaic glass can be applied to the adhesive film on the front side of the back contact cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can have a light transmittance of over 92%. It can protect the back contact cell 100 while minimizing impact on its efficiency. Simultaneously, the adhesive film bonds the photovoltaic glass and the back contact cell 100 together, providing sealing, insulation, waterproofing, and moisture protection for the back contact cell 100.

[0115] The backsheet can be attached to the adhesive film on the back of the back contact cell 100. The backsheet provides protection and support for the back contact cell 100, and has reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice is determined based on the specific circumstances and is not limited here. The backsheet, back contact cell 100, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0116] The photovoltaic system of this application embodiment includes the battery module described above.

[0117] In the photovoltaic system of this application embodiment, since the first fine grid 21 and the second fine grid 22 in the back contact cell 100 of the battery module are both located between the end connecting block 51 and the first edge 1011, and the distance between the first fine grid 21 and the first main grid 31 is greater than the distance between the second fine grid 22 and the first main grid 31, the distance between the partial non-polar fine grids between the end connecting block 51 and the first edge 1011 and the first main grid 31 is relatively large. This provides space for the head of the series connector connected to the end connecting block 51 and located between the end connecting block 51 and the first edge 1011, so that the distance between the head of the series connector and the fine grid with non-corresponding polarity is relatively large, reducing the risk of short circuit caused by the head of the series connector contacting the fine grid with non-corresponding polarity.

[0118] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may 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 combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0119] In the description of this specification, the references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do 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 one or more embodiments or examples.

[0120] Furthermore, the above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A back-contact battery, characterized in that, include: A silicon substrate, including 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 disposed on the silicon substrate, extending along the first direction and arranged along the second direction, the second direction intersecting the first direction; A first main gate is disposed on the silicon substrate, extends along the second direction, connects to the first polar fine gate and is spaced apart from the second polar fine gate; A plurality of connection structures are arranged along the second direction and disposed on the first main grid for connecting the serial connectors, including end connection blocks, wherein the end connection blocks are the connection structures closest to the first edge; The second polar fine grid includes a first fine grid and a second fine grid, both located between the boundary line of the end connecting block near the first edge and the first edge. There are multiple first fine grids, and the multiple first fine grids are arranged sequentially 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, the edge main gate being the first main gate closest to the second edge; the second polar fine gate includes a third fine gate and a fourth fine gate, the third fine gate being located between the edge main gate and the second edge, and the fourth fine gate being located between the edge main gate and the first edge; The back contact battery includes a second main grid and a first connecting grid. The second main grid is connected to the second polar fine grid and spaced apart from the first polar fine grid. The first connecting grid is located between the edge main grid and the second edge, connects to a plurality 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 distance between the first fine gate and the first main gate and the distance between the second fine gate and the first main gate is 0.1mm-0.8mm.

3. The back contact battery according to claim 1, characterized in that, The back contact battery satisfies the following formula: 0.2 ≤ A / B ≤ 0.9; Where A is the number of the first fine grids, and B is the number of the second polar 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 and last fine grids is 1mm-3mm.

5. The back contact battery according to claim 1, characterized in that, The connection structure includes a non-end connection block, which is located on the 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. 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 a plurality 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 connecting gate is greater than the length of the second connecting gate.

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

8. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1-7.

9. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 8.

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