A back-contact battery, battery module and photovoltaic system

Abstract

This application provides a back-contact battery, a battery module, and a photovoltaic system. The back-contact battery includes: a battery substrate having opposing first and second surfaces; the first surface including a first edge and a second edge arranged along a first direction, both extending along a second direction, the first and second directions intersecting; a doped layer disposed on the first surface; and a plurality of fine grids disposed on the doped layer, the plurality of fine grids arranged along the first direction and all extending along the second direction; wherein the doped layer includes a first doped region closest to the first edge and a plurality of second doped regions arranged along the first direction, a portion of the first doped region being located in a first overlapping region, and in the first direction, the width of the first doped region being greater than the width of the second doped region.

Description

[0001] This application claims priority to Chinese Patent Application No. 2025207339655, filed on April 17, 2025, entitled “A Back Contact Battery, Battery Module and Photovoltaic System”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photovoltaic technology, and in particular to a back contact battery, battery module and photovoltaic system. Background Technology

[0003] In back-contact battery modules, manufacturers typically overlap adjacent cells to eliminate the gap between them. However, overlapping cells increase the risk of microcracks and fragmentation during lamination.

[0004] Therefore, how to reduce the risk of microcracks and fragmentation of battery cells during lamination of back-contact battery modules has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides a connection structure, a battery module, and a photovoltaic system to address the technical problem of how to reduce the risk of microcracks and fragmentation of battery cells during lamination of back-contact battery modules.

[0006] This application provides a back-contact battery, a battery module, and a photovoltaic system. A back-contact battery includes: a battery substrate having opposing first and second surfaces; the first surface including a first edge and a second edge arranged along a first direction, both extending along a second direction, the first and second directions intersecting; a doped layer disposed on the first surface; and a plurality of fine gates disposed on the doped layer, the plurality of fine gates arranged along the first direction and extending along the second direction; wherein the plurality of doped regions include a first doped region closest to the first edge and a plurality of second doped regions arranged along the first direction, the width of the first doped region being greater than the width of the second doped region in the first direction.

[0007] Further, the fine gate includes a first fine gate closest to the first edge, the first fine gate being disposed in the first doped region; wherein, the first doped region includes a third edge and a fourth edge arranged along a first direction, the third edge and the fourth edge both extending along a second direction; in the first direction, the distance from the first fine gate to the third edge is a first spacing; in the first direction, the distance from the first fine gate to the fourth edge is a second spacing; the first spacing is greater than the second spacing.

[0008] Furthermore, the ratio of the first spacing to the second spacing is 4 to 6.

[0009] Furthermore, the first spacing is 200 micrometers to 500 micrometers.

[0010] Furthermore, in the first direction, the width of the first doped region is 600 micrometers to 950 micrometers.

[0011] Furthermore, it also includes a plurality of main gates, which are arranged along the second direction and all extend along the first direction. The main gates are electrically connected to the fine gates of the same polarity and are insulated from the fine gates of the opposite polarity.

[0012] Furthermore, the doped layer also includes a third doped region closest to the second edge, wherein the width of the third doped region is greater than the width of the second doped region in the first direction.

[0013] Furthermore, the back contact battery also includes a dicing region disposed between the first edge and the second edge, and the doped layer further includes a fourth doped region located between one of the second doped regions and the dicing region; in the first direction, the width of the fourth doped region is greater than the width of the second doped region.

[0014] This application also provides a battery assembly, which includes a battery string, the battery string including the back contact battery described above.

[0015] This application also provides a photovoltaic system, which includes the battery module as described above.

[0016] Thus, the back-contact solar cell in this application, by increasing the width of the first doped region closest to the first edge, allows sufficient space for the first doped regions to overlap, reducing the risk of microcracks and fragmentation during lamination. Simultaneously, there is sufficient space to set a fine grid in the first doped region, thereby effectively collecting the current from the first doped region. Furthermore, for back-contact solar cells, increasing the width of the first doped region increases the power-generating area of ​​the cell, thereby improving the cell's efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a photovoltaic system module provided in one embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the structure of a battery assembly provided in one embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the structure of a back contact battery provided in one embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the structure of a back contact battery provided in another embodiment of this application;

[0022] Figure 5 This is a schematic diagram of the structure of a back contact battery provided in another embodiment of this application;

[0023] Figure 6 This is a schematic diagram of the structure of a back contact battery provided in another embodiment of this application;

[0024] Figure 7 This is a schematic diagram of the partially overlapping structure of a battery assembly provided in another embodiment of this application;

[0025] Figure 8 This is a schematic diagram of the partially overlapping structure of a battery assembly provided in another embodiment of this application;

[0026] Figure 9 This is a schematic diagram of the structure of a back contact battery provided in another embodiment of this application;

[0027] Figure 10 This is a schematic diagram of the structure of a back contact battery provided in another embodiment of this application;

[0028] Key component symbols: 1000, Photovoltaic system; 1001, Battery module; 100, Back contact battery; 200, First cell; 300, Second cell; 101, First surface; 11, First edge; 12, Second edge; 13, First overlapping region; 14, Non-overlapping region; 15, Second overlapping region; 16, Cutting region; 20, Fine grid; 21, First fine grid; 31, First doped region; 32, Second doped region; 33, Third doped region; 34, Fourth doped region; 40, Main grid; 311, Third edge; 312, Fourth edge. Detailed Implementation

[0029] 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. 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 illustrative of this application and are not intended to limit this application.

[0030] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "top", "bottom", "lateral", "longitudinal", 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] Please see Figure 1 and Figure 2The photovoltaic system 1000 in this application embodiment may include the battery module 1001 in this application embodiment. The battery module 1001 in this application embodiment may include a plurality of battery strings, and the battery strings may include a plurality of back contact batteries 100 in this application embodiment. In each battery string, two adjacent back contact batteries partially overlap. The battery strings in the battery module 1001 may be connected in series, in parallel, or in a series-parallel combination to achieve current collection and output. For example, the connection between the battery strings can be achieved through busbars.

[0035] In this embodiment, the photovoltaic system 1000 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 for power generation, 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 1000 are not limited to these; that is, the photovoltaic system 1000 can be applied in all fields that require solar energy for power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system 1000 may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules 1001. For example, multiple battery modules 1001 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.

[0036] The accompanying drawings provided in this application are schematic diagrams, and some elements are not shown. Their purpose is to clearly describe the technical solution and highlight the key points of the application. They are not intended to limit the technical solution to exclude these unshown elements. In other words, the drawings are merely illustrative and do not represent a limitation on the specific form of the back contact battery 100.

[0037] like Figures 3 to 10As shown, the back contact battery 100 in this embodiment can be applied to a battery assembly 1001. The back contact battery 100 includes a battery substrate, a doped layer, and a plurality of fine grids 20. The battery substrate has a first surface 101 and a second surface opposite to each other. The first surface 101 includes a first edge 11 and a second edge 12 arranged along a first direction. Both the first edge 11 and the second edge 12 extend along a second direction, and the first direction intersects the second direction. The doped layer is disposed on the first surface 101. A plurality of fine grids 20 are disposed on the doped layer. The plurality of fine grids 20 are arranged along the first direction and all extend along the second direction. The first surface 101 also includes a first overlapping region 13 and a non-overlapping region 14 arranged sequentially along the first direction. The first edge 11 is a boundary line of the first overlapping region 13. All the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14. The first overlapping region 13 is used to overlap with an adjacent battery cell in the battery assembly 1001. The doped layer includes a first doped region 31 closest to the first edge 11 and a plurality of second doped regions 32 arranged along the first direction. A portion of the first doped region 31 is located in the first overlapping region 13, and in the first direction, the width D1 of the first doped region 31 is greater than the width D2 of the second doped region 32.

[0038] Thus, the back contact battery 100 in this application is provided with a first overlapping region 13, which is used to overlap with an adjacent battery cell in the battery assembly 1001. All the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, thereby reducing the thickness of the battery assembly 1001 and thus reducing the risk of microcracks and fragmentation of the back contact battery 100 during the lamination of the battery assembly 1001.

[0039] Specifically, the battery substrate is the main body of the back contact battery 100. For example, the battery substrate may include a silicon substrate, and may also include a dielectric layer, a doped layer, a passivation layer, etc., which can be set according to the actual situation.

[0040] It is understood that the battery substrate of the back contact battery 100 has a first surface 101 and a second surface, the second surface being the front side of the back contact battery 100 and the first surface 101 being the back side of the back contact battery 100, and the grid lines of the back contact battery 100 are all disposed on the first surface 101.

[0041] like Figures 3 to 9As shown, the first surface 101 of the back contact battery 100 includes a first overlapping region 13 and a non-overlapping region 14 arranged sequentially along a first direction. The first overlapping region 13 is used to overlap with an adjacent battery cell in the battery assembly 1001, and the first edge 11 is a boundary line of the first overlapping region 13. In the battery assembly 1001, the user can configure the back contact battery 100 to partially overlap with an adjacent battery cell. Specifically, the first overlapping region 13 of the back contact battery 100 overlaps with the adjacent battery cell.

[0042] The first surface 101 of the back contact cell 100 is further provided with a plurality of fine gates 20, which are used to contact the doped layer and collect charge carriers in the doped layer. The plurality of fine gates 20 includes positive electrode fine gates 20 and negative electrode fine gates 20 arranged alternately along a first direction, and the plurality of fine gates 20 all extend along a second direction. Wherein, all the fine gates 20 of the back contact cell 100 are located in the non-overlapping region 14.

[0043] It can be understood that "all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14" means that the projection of all the fine grids 20 on the first surface 101 is located in the non-overlapping region 14 of the back contact battery 100, and the projection of all the fine grids 20 on the first surface 101 is not located in the non-overlapping region 14.

[0044] Because the first overlapping region 13 of the back contact cell 100 is the part that overlaps with the adjacent cell. Therefore, by providing a fine grid 20 to avoid the first overlapping region 13 in the back contact cell 100, the thickness of the part of the back contact cell 100 that overlaps with the adjacent cell can be reduced, thereby reducing the thickness of the battery assembly 1001, and further reducing the risk of microcracks and fragmentation of the back contact cell 1000 during the lamination of the battery assembly 1001.

[0045] Meanwhile, by ensuring that all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, the user can prevent the fine grids 20 of the back contact battery 100 from physically contacting or being squeezed by adjacent battery cells when the back contact battery 100 overlaps with them. This avoids microcracks or short circuits between electrodes caused by the deformation of the fine grids 20 under pressure. Furthermore, in some cases, the height of the fine grids causes them to protrude from the surface of the battery cell. If the fine grid lines are placed in the overlapping region, the thickness of the overlapping region will increase, increasing the risk of microcracks. Therefore, the solution adopted in this embodiment can reduce the risk of microcracks.

[0046] For example, such as Figures 3 to 7As shown, the battery assembly 1001 includes a first battery cell 200, a back contact battery 100, and a second battery cell 300 arranged sequentially along a first direction. The back contact battery 100 overlaps with the first battery cell 200 in a first overlapping region 13, and the first battery cell 200 supports the first overlapping region 13 of the back contact battery 100. All the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, thereby reducing the thickness of the overlapping portion between the back contact battery 100 and the first battery cell 200, and further reducing the risk of microcracks and fragmentation of the back contact battery 100 during lamination of the battery assembly 1001.

[0047] It can be understood that the first battery cell 200 and the second battery cell 300 can also be the same battery cells as the back contact battery 100 provided in the embodiments of this application.

[0048] Specifically, the first surface 101 includes a first edge 11 and a second edge 12 arranged along a first direction, both the first edge 11 and the second edge 12 extending along a second direction, and the first edge 11 and the second edge 12 are two boundary lines of the first surface 101.

[0049] The doped layer includes multiple doped regions arranged along a first direction and extending along a second direction. The doped regions can be either P-type or N-type doped regions. Each fine gate 20 corresponds to a specific doped region. The fine gate 20 includes a positive fine gate 20 and a negative fine gate 20. The positive fine gate 20 contacts the P-type doped region and collects carriers from it, while the negative fine gate 20 contacts the N-type doped region and collects carriers from it.

[0050] In the back contact cell 100, multiple doped regions include a first doped region 31 closest to the first edge 11 and multiple second doped regions 32 arranged along a first direction. A portion of the first doped region 31 is located in a first overlapping region 13. In the first direction, the width D1 of the first doped region 31 is set to be greater than the width D2 of the second doped regions 32. Thus, by increasing the width D1 of the first doped region 31 closest to the first edge 11, the back contact cell 100 of this application allows more area of ​​the silicon wafer to be used to generate charge carriers. Furthermore, since a portion of the first doped region 31 is located in the first overlapping region 13, sufficient space is provided for the first doped regions 31 to overlap, reducing the risk of microcracks and fragmentation of the cell during lamination. Simultaneously, sufficient space is provided to set a fine grid 20 in the first doped region 31, thereby effectively collecting the current from the first doped region 31.

[0051] Understandably, in the prior art, a doped region is also provided at the overlapping part of the back contact battery 100 with the adjacent battery cell. However, since the width of the doped region at the edge is not wide enough, the narrow doped region cannot simultaneously meet the space requirements of the overlapping area and the arrangement requirements of the fine grid 20. This will cause the adjacent battery cell to cover the fine grid 20 provided in the edge doped region, thus making it impossible to collect the current in the edge doped region.

[0052] Therefore, in this embodiment, by increasing the width D1 of the first doped region 31 closest to the first edge 11, sufficient buffer space is provided for the physical overlap of the first overlapping region 13 of the back contact cell 100. This ensures that the back contact cell 100 does not compress the fine grid 20 disposed in the first doped region 31 when it overlaps with adjacent cells, thereby fully collecting the charge carriers in the first doped region 31 and further improving the photoelectric conversion efficiency of the back contact cell 100. In addition, for the back contact cell 100, increasing the width of the first doped region 13 can increase the power generation area of ​​the back contact cell 100 and improve the efficiency of the back contact cell 100.

[0053] Furthermore, in the embodiments of the application, the arrangement of the various doped regions in the doped layer can be varied. For example, multiple second doped regions 32 can be arranged along the first direction. The second doped regions 32 are arranged from near the first doped region 31 to near the second edge 12. In other words, the doped region closest to the second edge 121 is also a second doped region 32. In the first direction, the width of the doped region closest to the second edge 121 is also smaller than the width D1 of the first doped region 31.

[0054] For example, multiple second doped regions 32 can be arranged along the first direction. The second doped regions 32 are arranged from the vicinity of the first doped region 31 to the penultimate doped region in the doped layer. In other words, the doped region closest to the second edge 121 is not a second doped region 32. In this case, the width of the doped region closest to the second edge 121 can be set to be equal to the width D1 of the first doped region 31; or, the width of the doped region closest to the second edge 121 can be set to be greater than the width D2 of the second doped region 32.

[0055] For example, multiple second doped regions 32 may be arranged along the first direction. The second doped regions 32 are arranged from near the first doped region 31 to the middle part of the doped layer. No limitation is made here.

[0056] like Figure 3 and Figure 4As shown, further, in the first direction, the width D1 of the first doped region 31 is 600 micrometers to 950 micrometers. For example, it is 600 micrometers, 650 micrometers, 700 micrometers, 750 micrometers, 757 micrometers, 800 micrometers, 850 micrometers, 900 micrometers, and 950 micrometers. In this way, sufficient space can be left when the back contact battery 100 overlaps with the adjacent battery cell, avoiding physical contact between the adjacent battery cell and the fine grid 20 disposed in the first doped region 31. This allows the first fine grid 21 to fully collect the carriers in the first doped region 31, preventing the first fine grid 21 from being too far away from the first edge 11, which would cause some areas of the first doped region 31 to be unable to collect carriers due to excessive distance from the first fine grid 21, thereby avoiding current loss of the back contact battery 100.

[0057] In one possible implementation, the fine gate 20 includes a first fine gate 21 closest to the first edge 11, the first fine gate 21 being disposed in the first doped region 31; wherein, the first doped region 31 includes a third edge 311 and a fourth edge 312 arranged along a first direction, both the third edge 311 and the fourth edge 312 extending along a second direction; in the first direction, the distance from the first fine gate 21 to the third edge 311 is a first spacing D3; in the first direction, the distance from the first fine gate 21 to the fourth edge 312 is a second spacing D4; the first spacing D3 is greater than the second spacing D4. Thus, by setting the distance from the first fine gate 21 to the third edge 311 to be greater than the distance from the first fine gate 21 to the fourth edge 312, sufficient space can be ensured when the back contact cell 100 overlaps with adjacent cells, avoiding physical contact between adjacent cells and the fine gate 20 disposed in the first doped region 31, allowing the first fine gate 21 to fully collect the charge carriers of the first doped region 31, thereby further improving the photoelectric conversion efficiency of the back contact cell 100.

[0058] It is understood that in the prior art, the distance from the fine gate 20 to the two edges of the doped region is usually the same. However, in this embodiment, because part of the first doped region 31 is located in the first overlapping region 13, by setting the distance from the first fine gate 21 to the third edge 311 to be greater than the distance from the first fine gate 21 to the fourth edge 312, it can be ensured that the first fine gate 21 is completely located in the non-overlapping region 14 and is not located in the first overlapping region 13 at all, thereby eliminating the risk of mechanical interference between the first fine gate 21 and the solar cell.

[0059] Specifically, the ratio of the first spacing to the second spacing is 4 to 6, for example, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.4, 5.6, 5.8, or 6. This ensures that the first spacing D3 is sufficiently large, providing reliable clearance for the overlapping installation of adjacent cells and preventing physical contact between adjacent cells and the fine grid 20 located in the first doped region 31. Simultaneously, it prevents an excessive increase in the first spacing D3 from causing the second spacing D4 to become too small, thus preventing the first fine grid 21 from getting too close to the second edge 12 and causing problems such as difficulty in process alignment or excessively high local current density. Furthermore, by optimizing the ratio of the first spacing D3 to the second spacing D4, it also makes it easier for charge carriers generated in the portion of the first doped region 31 near the fourth edge 312 to be transported to the first fine grid 21, thereby facilitating carrier collection.

[0060] Specifically, the first spacing D3 is between 200 micrometers and 500 micrometers, for example, 200 micrometers, 230 micrometers, 250 micrometers, 280 micrometers, 300 micrometers, 350 micrometers, 380 micrometers, 400 micrometers, and 500 micrometers. Thus, by setting the first spacing D3 to be greater than or equal to 200 micrometers, reliable clearance space can be provided for the overlapping installation of adjacent solar cells, preventing physical contact between adjacent solar cells and the fine grid 20 located in the first doped region 31. Furthermore, by controlling the first spacing D3 to not exceed 500 micrometers, it can also prevent the first fine grid 21 from being too far away from the first edge 11, thus avoiding current loss in the back-contact cell 100.

[0061] Furthermore, the first spacing D3 can be matched with the width of the first overlapping region 13 in the first direction. When the first overlapping region 13 increases, the distance of the first spacing D3 can be increased accordingly; when the first overlapping region 13 decreases, the distance of the first spacing D3 can be decreased accordingly.

[0062] In one possible implementation, in the first direction, the ratio of the width D1 of the first doped region 31 to the width D2 of the second doped region 32 is 1.2 to 2.1, for example, 1.2, 1.4, 1.5, 1.7, 1.9, or 2.1. This allows sufficient space in the first doped region 31 to prevent adjacent cells from making physical contact with the fine grid 20 disposed in the first doped region 31; it also prevents the first fine grid 21 from being unable to adequately collect carriers in the first doped region 31 due to an excessively large area, thereby reducing current loss in the back-contact cell 100.

[0063] In one possible implementation, the first doped region 31 is a P-type doped region, and the first fine gate 21 is a positive electrode fine gate 20. It is understood that in the back contact battery 100, due to the difficulty of doping boron, the doping concentration in the P-type doped region is relatively low, resulting in insufficient holes generated in the P-type doped region and thus reducing the photoelectric conversion efficiency of the back contact battery 100. Therefore, to improve the photoelectric conversion efficiency of the back contact battery 100, this embodiment of the application sets the wider first doped region 31 as a P-type doped region, thereby expanding the hole generation area. Furthermore, by setting the first fine gate 21 as a positive electrode fine gate 20 to collect the holes in the first doped region 31, the hole collection efficiency can be improved, thereby increasing the photoelectric conversion efficiency of the back contact battery 100.

[0064] In one possible implementation, the back contact battery 100 is a back contact battery 100 with main grids 40. The back contact battery 100 also includes a plurality of main grids 40, which are arranged along a second direction and all extend along a first direction. The main grids 40 are electrically connected to fine grids 20 of the same polarity and are insulated from fine grids 20 of opposite polarity. All the main grids 40 of the back contact battery 100 are located in the non-overlapping region 14. Thus, by setting all the main grids 40 of the back contact battery 100 to be located in the non-overlapping region 14, all the main grids 40 and all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, and all the main grids 40 and all the fine grids 20 of the back contact battery 100 avoid the first overlapping region 13, thereby reducing the thickness of the battery assembly 1001, and further reducing the risk of microcracks and fragmentation of the back contact battery 100 during lamination of the battery assembly 1001.

[0065] Specifically, the plurality of main gates 40 include main gates 40 electrically connected to the P-type doped region and main gates 40 electrically connected to the N-type doped region.

[0066] Specifically, such as Figure 3 and Figure 4 As shown, the back contact battery 100 can be a back contact battery 100 without a main grid 40; or, as... Figure 5 and Figure 6 As shown, the back contact battery 100 can also be a back contact battery 100 with a main grid 40, and this is not limited here. When the back contact battery 100 is a back contact battery 100 without a main grid 40, all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14. When the back contact battery 100 is a back contact battery 100 with a main grid 40, all the main grids 40 and all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14.

[0067] like Figure 4 and Figure 6As shown, in one possible implementation, the first surface 101 further includes a second overlapping region 15, and the second edge 12 is a boundary line of the second overlapping region 15; the first overlapping region 13, the non-overlapping region 14 and the second overlapping region 15 are arranged sequentially along a first direction, all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, and the second overlapping region 15 is used to overlap with another adjacent battery cell in the battery assembly 1001.

[0068] Thus, the back contact battery 100 in this application is provided with a second overlapping region 15, which is used to overlap with another adjacent battery cell in the battery assembly 1001. All the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14. The first overlapping region 13 and the second overlapping region 15 are not provided with fine grids 20, thereby reducing the thickness of the battery assembly 1001 and thus reducing the risk of microcracks and fragmentation of the back contact battery 100 during the lamination of the battery assembly 1001.

[0069] Similarly, as Figure 4 As shown, the back contact battery 100 can be a back contact battery 100 without a main grid 40; or, as... Figure 6 As shown, the back contact battery 100 can also be a back contact battery 100 with a main grid 40, which is not limited here. When the back contact battery 100 is a back contact battery 100 without a main grid 40, all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, and neither the first overlapping region 13 nor the second overlapping region 15 is provided with fine grids 20. When the back contact battery 100 is a back contact battery 100 with a main grid 40, all the main grids 40 and all the fine grids 20 of the back contact battery 100 are located in the non-overlapping region 14, and neither the first overlapping region 13 nor the second overlapping region 15 is provided with fine grids 20 and main grids 40.

[0070] It is understandable that there can be multiple overlapping arrangements of the back-contact cells 100 in the battery assembly 1001. For example, as... Figure 8 As shown, the battery assembly 1001 includes a first battery cell 200, a back contact battery 100, and a second battery cell 300 arranged sequentially along a first direction. The back contact battery 100 overlaps with the first battery cell 200 in a first overlapping region 13 of the back contact battery 100, and the first battery cell 200 supports the first overlapping region 13 of the back contact battery 100. The back contact battery 100 overlaps with the second battery cell 300 in a second overlapping region 15 of the back contact battery 100, and the second battery cell 300 supports the second overlapping region 15 of the back contact battery 100. Both the first battery cell 200 and the second battery cell 300 support the first surface 101 of the back contact battery 100.

[0071] Therefore, by setting all the fine grids 20 of the back contact battery 100 to be located in the non-overlapping area 14, and not setting fine grids 20 in the first overlapping area 13 and the second overlapping area 15, the user can reduce the thickness of the overlapping part of the back contact battery 100 and the second battery cell 300, thereby reducing the risk of microcracks and fragments of the back contact battery 100 during the lamination of the battery assembly 1001.

[0072] In addition, by setting neither the fine grid 20 in the first overlapping area 13 nor the second overlapping area 15 of the back contact battery 100, the user can reduce the thickness of the overlapping part between the back contact battery 100 and the first battery cell 200, and at the same time reduce the thickness of the overlapping part between the back contact battery 100 and the second battery cell 300, thereby further reducing the risk of microcracks and fragmentation of the back contact battery 100 during the lamination of the battery assembly 1001.

[0073] like Figure 4 and Figure 6 As shown, in one possible implementation, the doped layer further includes a third doped region 33 closest to the second edge 12. A portion of the third doped region 33 is located in the second overlapping region 15. In the first direction, the width D5 of the third doped region 33 is greater than the width D2 of the second doped region 32. Thus, by increasing the width D5 of the third doped region 33 closest to the second edge 12, and ensuring that a portion of the third doped region 33 is located in the second overlapping region 15, the back contact battery 100 of this application allows sufficient space for the third doped region 33 to overlap. Simultaneously, sufficient space is provided for the fine grid 20 to be disposed in the third doped region 33, thereby effectively collecting the current from the third doped region 33. Furthermore, the third doped region 33 can be made sufficiently wide to reduce the risk of mechanical interference between the fine grid 20 disposed in the third doped region 33 and other battery cells when the back contact battery 100 overlaps with them.

[0074] It is understandable that the structure and gate line arrangement of the third doped region 33 are basically the same as those of the first doped region 31. The only difference is that the third doped region 33 and the first doped region 31 are located in different positions. The structure and gate line arrangement of the third doped region 33 can be referred to the first doped region 31, and will not be described again here.

[0075] In one possible implementation, specifically, the back contact battery 100 in the embodiments of this application can be a whole battery cell, or a sliced ​​battery cell formed by cutting a whole solar cell, such as a two-slice battery cell, a three-slice battery cell, a four-slice battery cell, etc., which are not limited here.

[0076] like Figure 9As shown, the back contact battery 100 also includes a cutting region 16, which is disposed between the first edge 11 and the second edge 12. The doped layer also includes a fourth doped region 34 located between one of the second doped regions 32 and the cutting region 16. In the first direction, the width D6 of the fourth doped region 34 is greater than the width D2 of the second doped region 32.

[0077] It is understood that the back contact battery 100 can be a scalable cell, and the user can cut the back contact battery 100 from the cutting area 16 to divide the back contact battery 100 into multiple cells. Moreover, no doped area or grid lines are provided in the cutting area 16.

[0078] The doped layer of the back contact cell 100 also includes a fourth doped region 34, which is located between the dicing region 16 and one of the multiple second doped regions 32. Specifically, there are two fourth doped regions 34, located on opposite sides of the dicing region.

[0079] Understandably, when the battery cells cut from the back contact battery 100 are stacked to form battery strings, the cut battery cells will overlap with other battery cells. Specifically, a portion of the fourth doped region 34 will overlap with other battery cells.

[0080] Therefore, in the first direction, by setting the width D6 of the fourth doped region 34 to be greater than the width D2 of the second doped region 32, sufficient space is provided for the fourth doped region 34 to overlap. Simultaneously, sufficient space is also provided in the fourth doped region 34 to house the fine grid 20, allowing the fine grid 20 to effectively collect the current from the fourth doped region 34. Furthermore, the fourth doped region 34 can be made sufficiently wide to reduce the risk of mechanical interference between the fine grid 20 in the fourth doped region 34 and other battery cells when the battery cells cut from the back contact battery 100 overlap with other battery cells.

[0081] It is understandable that the structure and gate line arrangement of the fourth doped region 34 are basically the same as those of the first doped region 31. The only difference is that the fourth doped region 34 and the first doped region 31 are located in different positions. The structure and gate line arrangement of the fourth doped region 34 can be referred to the first doped region 31, and will not be described again here.

[0082] It is understood that in such an embodiment, the battery assembly 1001 may further include a frame, a back sheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back surfaces of the back contact battery 100, the photovoltaic glass, and adjacent back contact batteries 100, 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.

[0083] Photovoltaic glass can be applied to the encapsulating 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 achieve a light transmittance of over 92%. It can protect the back contact cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back contact cell 100 together, providing sealing, insulation, and waterproofing / moisture protection for the back contact cell 100.

[0084] The backsheet can be attached to the adhesive film on the back side 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 integrated into a frame. The frame serves as the main external support structure for the entire battery module 1001, providing stable support and installation for the battery module 1001. For example, the battery module 1001 can be installed at the desired location via the frame.

[0085] 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.

[0086] Furthermore, the above description is merely a preferred embodiment of this application and is 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 protection scope of this application.

Claims

1. A back-contact battery for use in a battery assembly, characterized in that, The back contact battery includes: A battery substrate having opposing first and second surfaces, the first surface including a first edge and a second edge arranged along a first direction, both the first edge and the second edge extending along a second direction, the first direction intersecting the second direction; A doped layer is disposed on the first surface; Multiple fine gates are disposed on the doped layer, and the multiple fine gates are arranged along the first direction and all extend along the second direction; The doped layer includes a first doped region closest to the first edge and a plurality of second doped regions arranged along the first direction. In the first direction, the width of the first doped region is greater than the width of the second doped region. The first surface further includes a first overlapping region and a non-overlapping region arranged sequentially along the first direction. The first overlapping region is used to overlap with an adjacent cell in the battery assembly. The first edge is a boundary line of the first overlapping region. A portion of the first doped region is located in the first overlapping region. All the fine grids of the back contact cell are located in the non-overlapping region. The back contact battery is a gridless back contact battery; or, the back contact battery includes a plurality of main grids, the plurality of main grids are arranged along the second direction and all extend along the first direction, the main grids are electrically connected to the fine grids of the same polarity, the main grids are insulated from the fine grids of the opposite polarity, and all the main grids of the back contact battery are located in the non-overlapping region.

2. The back contact battery according to claim 1, characterized in that, The fine gate includes a first fine gate closest to the first edge, and the first fine gate is disposed in the first doped region; The first doped region includes a third edge and a fourth edge arranged along a first direction, both the third edge and the fourth edge extending along a second direction, and the third edge being located between the first edge and the fourth edge; In the first direction, the distance from the first fine gate to the third edge is the first spacing; In the first direction, the distance from the first fine gate to the fourth edge is the second spacing; The first spacing is greater than the second spacing.

3. The back contact battery according to claim 2, characterized in that, The ratio of the first spacing to the second spacing is 4 to 6.

4. The back contact battery according to claim 2, characterized in that, The first spacing is 200 micrometers to 500 micrometers.

5. The back contact battery according to claim 1, characterized in that, In the first direction, the width of the first doped region is 600 micrometers to 950 micrometers.

6. The back contact battery according to claim 1, characterized in that, The doped layer further includes a third doped region closest to the second edge, wherein the width of the third doped region is greater than the width of the second doped region in the first direction.

7. The back contact battery according to claim 1, characterized in that, The back contact battery further includes a dicing region disposed between the first edge and the second edge, and the doped layer further includes a fourth doped region located between one of the second doped regions and the dicing region; in the first direction, the width of the fourth doped region is greater than the width of the second doped region.

8. A battery assembly, characterized in that, The battery assembly includes a battery string, which includes a plurality of back-contact batteries as described in any one of claims 1 to 7.

9. A photovoltaic system, characterized in that, The photovoltaic system includes the battery module as described in claim 8.

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