Back contact cells and back contact stacked cells and photovoltaic modules

Abstract

The application provides a back contact cell, a back contact laminated cell and a photovoltaic module. The back contact cell comprises a substrate, a grid line and an isolation area. The grid line comprises a first grid line and a second grid line. The first grid line and the second grid line are arranged at intervals along a first direction. The first grid line and the second grid line are different in polarity. The first grid line comprises a first body segment and a plurality of second body segments which are connected to each other. The first body segment extends along a second direction. The second body segments are arranged at intervals along the second direction. At least part of the second body segments is inclined relative to the first body segment. The second grid line comprises a third body segment and a fourth body segment which have the same function as the first grid line. The first grid line and the second grid line arranged at intervals along the first direction can reduce the number of the isolation area. The second body segments and the fourth body segments arranged at an inclination can cover a larger power generation area of the back contact cell, and improve the power generation efficiency of the back contact cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic module technology, and in particular to a back-contact cell, a back-contact tandem cell, and a photovoltaic module. Background Technology

[0002] BC cells, short for back contact cells, are based on IBC cells (interdigitated back contact cells). The biggest difference between them and other crystalline silicon cell routes is that the emitter, surface field, and metal electrodes are all located on the back of the cell and are distributed in an interdigitated manner. There are no grid lines blocking the front surface of the cell, which maximizes the use of incident light, reduces optical loss, and brings more effective power generation area.

[0003] The sub-grids of different polarities are arranged in a cross pattern, and an isolation area is set between the sub-grids of different polarities. However, the isolation area occupies a large area, resulting in a small area covered by the fine grid lines, which is not conducive to the power generation efficiency of the back contact battery. Utility Model Content

[0004] This application provides a back-contact battery, a back-contact tandem battery, and a photovoltaic module. The back-contact battery can improve the power generation efficiency of the photovoltaic module and increase the area of ​​the power generation region.

[0005] This application provides a back contact battery, comprising: a substrate; grid lines disposed on the substrate; and an isolation region disposed on the substrate.

[0006] The grid line includes a first grid line and a second grid line, which are spaced apart along a first direction. The first grid line and the second grid line have different polarities. The isolation region is located between the first grid line and the second grid line. The first grid line includes a first body segment and a plurality of second body segments that are interconnected. The first body segment extends along a second direction, and each of the second body segments is spaced apart from the first body segment along the second direction. At least a portion of the second body segment is inclined relative to the first body segment. The second grid line includes a third body segment and a plurality of fourth body segments that are interconnected. The third body segment extends along the second direction, and each of the fourth body segments is spaced apart from the third body segment along the second direction. At least a portion of the fourth body segment is inclined relative to the third body segment.

[0007] In this design, the first and second grid lines have different polarities. They are spaced apart along a first direction and extend along a second direction, with an isolation region between them, also extending along the second direction. This ensures that the first and second grid lines, with their different polarities, reside in their respective independent regions. The isolation region between them prevents short circuits, guaranteeing the stability and reliability of the back-contact battery during operation. The first grid line comprises multiple interconnected first body segments and multiple second body segments. The first body segments extend along the second direction. Because the isolation region isolates the areas containing the first and second grid lines into block-shaped regions extending along the second direction, the first body segments extending along the second direction can occupy as much space as possible in that direction, improving the grid line's electron collection efficiency. The second body segments, spaced apart along the second direction on the first body segments and extending outwards from both sides of the first body segments, can collect electrons that the first body segments on either side cannot collect. At least a portion of the second body segment is inclined relative to the first body segment. This partially inclined arrangement increases the extension distance of the second body segment, thereby improving its ability to collect current and further enhancing the power generation efficiency of the back contact battery. Similarly, the third body segment functions the same as the first body segment, and the fourth body segment functions the same as the second body segment, differing only in polarity, which will not be elaborated upon here.

[0008] In one possible design, the angle between the second body segment and the first direction is α, and 0° < α ≤ 10°;

[0009] The angle between the fourth body segment and the first direction is b, and 0° < b ≤ 10°.

[0010] In this solution, when the angle α between the second body segment and the first direction is too large, the extension length of the second body segment is too long, resulting in a longer current transmission path. Although the extended second body segment can collect more current, the increased resistance loss due to the increased length leads to increased efficiency and power loss in the back contact battery, which is detrimental to the power generation efficiency of the back contact battery. In this application, the angle α between the second body segment and the first direction is limited to 0° < α ≤ 10°. The second body segment, tilted at a certain angle, can extend to a longer length, thus collecting current over a larger area. Furthermore, the current collected by the extended portion is greater than the resistance loss caused by the increased length, balancing the impact of the extended portion on the power generation efficiency of the back contact battery in terms of current collection and resistance loss, thereby improving the power generation efficiency of the back contact battery. Since the fourth body segment differs from the second body segment only in polarity, the technical effect of limiting the angle b between the fourth body segment and the first direction to 0° < b ≤ 10° is the same as that of the second body segment, and will not be described in detail here.

[0011] In one possible design, the inclination directions of the second body segments located on opposite sides of the same first body segment along the first direction are opposite.

[0012] The fourth body segments, located on opposite sides of the same third body segment along the first direction, have opposite inclination directions.

[0013] In this design, the second body segments, located on opposite sides of the first body segment along the first direction, are tilted in opposite directions, forming a mirror-symmetrical current collection network on both sides of the first body segment. This design reduces charge collection dead zones on both sides of the first body segment, and the symmetrical structure provides uniformity, which helps improve the strength of the back contact battery and reduces damage and breakage. The fourth body segment has the same effect as the second body segment and will not be described in detail here.

[0014] In one possible design, in a second body segment disposed along a second direction within the same first body segment, at least one of the second body segments has an inclination direction opposite to that of the other second body segments.

[0015] In the fourth body segment disposed along the second direction in the same third body segment, at least one of the fourth body segments has an inclination direction opposite to that of the other second body segments.

[0016] In this design, at least one second segment located on either side of the first body segment has an inclination direction opposite to that of the other second body segments. When the charge generated by the back contact battery diffuses to the periphery of the first body segment, the second body segments with opposite inclination directions can work together to eliminate the charge collection dead zones of the first body segment, thereby improving the power generation efficiency of the back contact battery. The effect of the fourth body segment is the same as that of the second body segments, and will not be described in detail here.

[0017] In one possible design, the first gate line includes 200 to 500 second body segments, the second gate line includes 200 to 500 fourth body segments, and / or;

[0018] The distance between adjacent second body segments is 0.3mm to 0.8mm, and the distance between adjacent fourth body segments is 0.3mm to 0.8mm.

[0019] In this scheme, when the number of second body segments on the first grid line is too small, the current collection network formed by the second body segments is too sparse, resulting in a large number of uncovered charge collection blind areas on the surface of the back contact battery, leading to charge waste and low power generation efficiency of the back contact battery. When the number of second body segments on the first grid line is too large, the second body segments are excessively densely arranged within a limited area. Too many second body segments increase the resistance loss of the current, reducing the power generation efficiency of the back contact battery. Moreover, too many second body segments will also occupy the surface space of the back contact battery, obstructing the surface and thus affecting the efficiency of the back contact battery. In this embodiment, when the number of second body segments is controlled within the range of 200 to 500, the second body segments form a denser current collection network, reducing the charge capture blind areas of the back contact battery, and the resistance loss generated by the second body segments is small, so the increase in current collection is negligible compared to the increase in the number of second body segments. This improves the power generation efficiency and current collection efficiency of the back contact battery. Similarly, the effect of the fourth body segment is the same as that of the second body segment, and will not be described in detail here.

[0020] When the spacing between adjacent second body segments is too small, their excessively dense arrangement can obstruct the surface of the back contact battery, affecting its efficiency. Furthermore, excessively dense second body segments are difficult to manufacture, increasing production costs. Conversely, when the spacing between adjacent second body segments is too large, the sparse arrangement creates numerous charge collection dead zones on the back contact battery, reducing its efficiency. In this embodiment, the distance between adjacent second body segments is between 0.3mm and 0.8mm, resulting in a moderate density that covers most of the back contact battery surface, reducing charge collection dead zones and preventing wasted performance due to excessive density, thus improving the battery's power generation efficiency. Similarly, the fourth body segment has the same effect as the second body segment and will not be described in detail here.

[0021] In one possible design, the back contact battery further includes a doped region disposed on the substrate. The doped region includes a first polar doped region and a second polar doped region, wherein the polarities of the first polar doped region and the second polar doped region are opposite. The isolation region is located between the first polar doped region and the second polar doped region. The first gate line is disposed in the first polar doped region, and the second gate line is disposed in the second polar doped region.

[0022] In existing technology, a first polarity doped region and a second polarity doped region are provided on the back side of a back contact battery, and a positive electrode and a negative electrode are formed on the first polarity doped region and the second polarity doped region, respectively. Grid lines are disposed on the first polarity doped region or the second polarity doped region to collect currents of different polarities. To insulate the grid lines with different polarities, an insulating layer is required at the ends of the grid lines close to the opposite polarity grid lines to avoid short circuits caused by the connection of grid lines with different polarities. Typically, the grid lines with different polarities are interlaced, causing the first polarity doped region and the second polarity doped region to also interlaced and form a slender structure. This makes them prone to cross-doping during production, resulting in a decrease in the power generation efficiency of the back contact battery.

[0023] In this design, the first and second gate lines with different polarities are both located within a rectangular area. This means the first and second polarity doped regions can be arranged in a rectangular pattern, with the isolation region situated between them. This clear structure facilitates the manufacturing of the doped regions. It also reduces the possibility of interference between different doped regions, improving the stability and reliability of back-contact battery power generation.

[0024] In one possible design, the size of the isolation zone along the first direction is d1, which satisfies 0.03mm≤d1≤0.15mm.

[0025] In this design, when the dimension d1 of the isolation region along the first direction is small, the distance between the first polarity doped region and the second polarity doped region on both sides of the isolation region is too close. During the production process, mixing between the first polarity doped region and the second polarity doped region is likely to occur, causing the grid lines on the doped regions with different polarities to be prone to short circuits, thus reducing the power generation efficiency of the back contact battery. When the dimension d1 of the isolation region along the first direction is large, the isolation region occupies too large a surface area of ​​the back contact battery, resulting in a smaller area available for power generation and a decrease in the power generation efficiency of the back contact battery. In this embodiment, the dimension d1 of the isolation region along the first direction is limited to 0.03mm to 0.15mm to ensure effective isolation between the first doped region and the second doped region, while not occupying too large an area. This ensures that the back contact battery has sufficient area for power generation, improving the power generation efficiency and operational stability of the back contact battery.

[0026] In one possible design, the minimum spacing between the grid line and the isolation area is d2, which satisfies 0.05mm≤d2≤0.3mm.

[0027] In this design, when the spacing d2 between the grid lines and the isolation region is too small, the grid lines on both sides of the isolation region are too close together. This can easily lead to breakdown when the current is too high, damaging the back contact battery and affecting its power generation efficiency. When the spacing d2 between the grid lines and the isolation region is too large, a large open area is created between them. Charge generated in this area cannot be effectively collected by the grid lines, resulting in wasted power generation and reduced power generation efficiency. In this embodiment, the minimum spacing d2 between the grid lines and the isolation region is limited to 0.05mm to 0.3mm. This allows the grid lines to collect charge over a larger area while preventing breakdown of the grid lines on both sides of the isolation region, thus improving the power generation efficiency of the back contact battery and ensuring its operational stability.

[0028] In one possible design, the back-contact stacked battery includes a top battery and a bottom battery connected to each other, wherein the top battery is a perovskite battery and the bottom battery is a back-contact battery.

[0029] In this scheme, compared with monocrystalline silicon solar cells, back-contact tandem cells have higher efficiency and power generation. Furthermore, back-contact tandem cells using back-contact cells as the bottom cell offer advantages such as no current mismatch, high process tolerance, and wide applicability. Simultaneously, compared to two-terminal tandem cells, three-terminal tandem cells formed by perovskite cells and back-contact cells can have an additional electrode to output mismatch current, which helps ensure relatively higher power operation of the back-contact tandem cells. Moreover, the voltage matching requirements are less affected by solar spectrum variations than the current requirements. When the back-contact cell is used as the bottom cell, a two-terminal series structure can be constructed by using electrodes with opposite contact polarities, achieving a conversion from three-terminal to two-terminal. The back-contact cell has a textured surface, and conformal deposition and growth of perovskite on this surface improves the utilization of incident light. Back-contact tandem cells made using perovskite cells and back-contact cells do not require consideration of current matching and have high tolerance for perovskite band gap and thickness. Three-terminal back-contact stacked batteries have a wider range of applications and can achieve high-power operation in different outdoor environments, which is more in line with actual usage needs.

[0030] In one possible design, the photovoltaic module includes at least one cell string, which comprises multiple cells, such as back-contact cells or back-contact tandem cells. Assembling cells into a cell string increases the integration of the photovoltaic module, thereby improving its power generation efficiency.

[0031] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0032] Figure 1 A schematic diagram of the structure of the back contact battery provided in this application in one embodiment;

[0033] Figure 2 A schematic diagram of the structure of the back contact battery provided in this application in another embodiment;

[0034] Figure 3 A schematic diagram of the structure of the back contact battery provided in this application in yet another embodiment;

[0035] Figure 4 This is a schematic diagram of the back contact battery stack provided in this application;

[0036] Figure 5 This is a schematic diagram of the back contact stacked battery structure in this application;

[0037] Figure 6 This is a schematic diagram of the stacked battery with back contact in this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-Base;

[0040] 2-Doped region;

[0041] 21 - First polar doped region;

[0042] 22 - Second polar doped region;

[0043] 3-grid lines;

[0044] 31 - First grid line;

[0045] 311 - Second body segment;

[0046] 312 - First body segment;

[0047] 32 - Second grid line;

[0048] 321 - Fourth body segment;

[0049] 322 - Third body segment;

[0050] 6-Isolation Zone;

[0051] 7-Back contact stacked battery;

[0052] 71 - Protective layer;

[0053] 72-Transparent conductive layer;

[0054] 73 - Electron transport layer;

[0055] 74-Perovskite layer;

[0056] 75 - Hole transport layer;

[0057] 76-Composite layer;

[0058] 77-Back contact battery;

[0059] 78-Perovskite solar cells;

[0060] X - First direction;

[0061] Y - Second direction.

[0062] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0063] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0064] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0065] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0066] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0067] As a renewable and clean energy source, solar energy has led to extensive research into photovoltaic (PV) power generation technology, resulting in the rapid development of the PV power generation industry in recent years. A typical PV power generation system includes multiple components such as PV modules, DC-DC converters, and inverters. PV modules perform photoelectric conversion, transforming the energy from sunlight into direct current (DC) electricity. DC-DC converters collect electrical energy from the PV modules and convert the voltage before outputting it. Inverters receive the electrical energy from the DC-DC converter and convert it into alternating current (AC) electricity. The AC electricity is then transmitted to the grid via a grid-connected transformer, thus connecting the PV power generation system to the grid. PV modules are the core component of a PV power generation system. Each PV module includes at least one cell string, which contains multiple cells, such as back-contact cells (77) or back-contact tandem cells (7).

[0068] The full name of BC cell is back contact cell 77. Its basic type is IBC cell (interdigitated back contact cell 77). The biggest difference between it and other crystalline silicon cell routes is that the emitter, surface field and metal electrode are all made on the back of the cell and are interdigitated. There are no grid lines on the front surface of the cell to block the light, which maximizes the use of incident light, reduces optical loss, brings more effective power generation area, has high conversion efficiency and is more aesthetically pleasing.

[0069] The current-carrying structure in a solar cell is the grid line 3, a series of metal lines located on the cell surface. These are crucial components of a photovoltaic cell, serving to collect and transport electrons. These grid lines 3 are typically made of silver, aluminum, or other conductive materials and are printed or deposited onto the silicon wafer surface of the solar cell. When a photovoltaic cell is operating, sunlight shines on the silicon wafer, converting light energy into electrical energy and generating electrons and holes. The grid lines 3 rapidly guide these electrons to the edge of the cell so they can be collected and utilized by external circuitry.

[0070] Specifically, there are two types of grid lines 3: the thicker ones are the main grid lines, which are wider metal lines responsible for collecting current from the fine grid lines and transmitting it to the battery's output. The thinner ones are the fine grid lines, which are thinner metal lines that extend from the main grid lines to the region of the battery where electron-hole pairs are generated, helping to collect electrons dispersed throughout the battery surface.

[0071] This application provides a back contact battery 77, which improves the efficiency of the back contact battery 77 by rearranging the grid line 3 arrangement area.

[0072] This application provides a back contact battery 77, such as Figure 1As shown, the back contact battery 77 includes a substrate 1, grid lines 3, and an isolation region 6. The grid lines 3 and the isolation region 6 are disposed on the substrate 1. The grid lines 3 include a first grid line 31 and a second grid line 32, which are spaced apart along a first direction X. The first grid line 31 and the second grid line 32 have different polarities. The isolation region 6 is located between the first grid line 31 and the second grid line 32, and the extension direction of the isolation region 6 is the same as the direction of the first grid line 31 and the second grid line 32. The first grid line 31 includes a first body segment 312 and a plurality of second body segments 311 connected to each other. The first body segment 312 extends along a second direction Y, and the second body segments 311 are spaced apart along the second direction Y from the first body segment 312. At least a portion of the second body segments 311 is inclined relative to the first body segment 312.

[0073] The second grid line 32 includes a third body segment 322 and a plurality of fourth body segments 321 connected to each other. The third body segment 322 extends along the second direction Y, and the fourth body segments 321 are spaced apart from the third body segment 322 along the second direction Y. At least a portion of the fourth body segments 321 is inclined relative to the third body segment 322.

[0074] In this embodiment, the first gate line 31 and the second gate line 32 have different polarities. The first gate line 31 and the second gate line 32 are spaced apart along the first direction X and extend along the second direction Y. An isolation region 6 is provided between the first gate line 31 and the second gate line 32, that is, the isolation region 6 also extends along the second direction Y. This allows the first gate line 31 and the second gate line 32 with different polarities to be in their own independent regions. The isolation region 6 is provided between the two to ensure that a short circuit will not occur, thus ensuring the stability and reliability of the back contact battery 77 during operation. The first grid line 31 includes multiple interconnected first body segments 312 and multiple second body segments 311. The first body segments 312 extend along the second direction Y. Since the isolation region 6 isolates the areas where the first grid line 31 and the second grid line 32 are located into block-shaped regions extending along the second direction Y, the first body segments 312 extending along the second direction Y can occupy as much space as possible in the second direction Y, improving the collection efficiency of the grid line 3 for electrons. The second body segments 311, which are spaced apart along the second direction Y on the first body segments 312, are located on both sides of the first body segments 312 and extend outward, and can collect electrons that the first body segments 312 cannot collect on both sides of the first body segments 312. At least a portion of the second body segments 311 are inclined relative to the first body segments 312. The at least partially inclined second body segments 311 can increase the extension distance of the second body segments 311, that is, improve the ability of the second body segments 311 to collect current, and further improve the power generation efficiency of the back contact battery 77. Similarly, the function of the third body segment 322 is the same as that of the first body segment 312, and the function of the fourth body segment 321 is the same as that of the second body segment 311. The only difference is the polarity, which will not be elaborated on here.

[0075] Specifically, in the prior art, the second body segment 311 and the fourth body segment 321 extend along the first direction X, and the isolation region 6 is disposed between the second body segment 311 and the fourth body segment 321. Since the second body segment 311 and the fourth body segment 321 are more densely packed than the first body segment 312 and the third body segment 322, the number of isolation regions 6 disposed between the second body segment 311 and the fourth body segment 321 is larger, occupying a larger area and resulting in a smaller area capable of generating electricity, thus reducing power generation efficiency. In this embodiment, the isolation region 6 is disposed between the first and second segments, which have a lower density, thereby reducing the area occupied by the isolation region 6, increasing the area of ​​the power generation area, and further improving the power generation efficiency of the back contact battery 77.

[0076] In some embodiments, such as Figure 1 As shown, the angle between the second body segment 311 and the first direction X is α, satisfying 0°<a≤10°. For example, α can be: 0.5°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 9.5°, etc.

[0077] The angle between the fourth body segment 321 and the first direction X is b, which satisfies 0° < b ≤ 10°. For example, b can be 0.5°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 9.5°, etc.

[0078] When the angle α between the second body segment 311 and the first direction X is too large, the extension length of the second body segment 311 is too long, resulting in a longer current transmission path. Although the extended second body segment 311 can collect more current, the increased resistance loss due to the extended length leads to increased efficiency and power loss of the back contact battery 77, which is detrimental to the power generation efficiency of the back contact battery 77. In this application, the angle α between the second body segment 311 and the first direction X is limited to 0° < α ≤ 10°. The second body segment 311, which is tilted at a certain angle, can extend to a longer length, that is, collect current over a larger area. Moreover, the current collected by the extended portion is greater than the resistance loss caused by the increased length, thus balancing the impact of the extended portion on the power generation efficiency of the back contact battery 77 in terms of current collection and resistance loss, thereby improving the power generation efficiency of the back contact battery 77. Since the fourth body segment 321 and the second body segment 311 differ only in polarity, the technical effect of limiting the angle b between the fourth body segment 321 and the first direction X to 0°<b≤10° is the same as that of the second body segment 311, and will not be described in detail here.

[0079] In some embodiments, such as Figure 1As shown, a second body segment 311 is provided on both sides of the first body segment 312, and the inclination directions of the second body segments 311 located on opposite sides of the same first body segment 312 along the first direction X are opposite.

[0080] A fourth body segment 321 is provided on each of the opposite sides of the third body segment 322. The fourth body segments 321 located on opposite sides of the same third body segment 322 along the first direction X have opposite tilt directions.

[0081] In this embodiment, the second body segments 311 located on opposite sides of the same first body segment 312 along the first direction X are tilted in opposite directions, forming a mirror-symmetrical current collection network on both sides of the first body segment 312. This design reduces the charge collection dead angles on both sides of the first body segment 312, and the symmetrical arrangement of the structure is uniform, which helps to improve the strength of the back contact battery 77 and reduce the occurrence of damage and breakage of the back contact battery 77. The effect of the fourth body segment 321 is the same as that of the second body segment 311, and will not be described in detail here.

[0082] In some embodiments, such as Figure 2 As shown, the second body segment 311 and the fourth body segment 321, which are disposed on adjacent first body segments 312 and third body segments 322, are inclined in opposite directions in the first direction X.

[0083] In this embodiment, the second body segment 311 and the fourth body segment 321 on the adjacent first body segment 312 and third body segment 322 are tilted in opposite directions, so that the ends of the second body segment 311 and the fourth body segment 321 near the isolation area 6 can be staggered along the second direction Y, increasing the distance between the ends of the second body segment 311 and the fourth body segment 321, reducing the occurrence of breakdown, and improving the stability and reliability of the back contact battery 77 during operation.

[0084] In some embodiments, such as Figure 3 As shown, in the second body segment 311 disposed in the same first body segment 312 along the second direction Y, the tilting direction of at least one second body segment 311 is opposite to the tilting direction of the other second body segments 311.

[0085] In the fourth body segment 321 disposed along the second direction Y in the same third body segment 322, the tilt direction of at least one fourth body segment 321 is opposite to the tilt direction of the other fourth body segments 321.

[0086] In this embodiment, at least one second segment disposed on both sides of the first body segment 312 has an inclination direction opposite to that of the other second body segments 311. When the charge generated by the back contact battery 77 diffuses to the periphery of the first body segment 312, the second body segments 311 with opposite inclination directions can work together to eliminate the charge collection dead zone of the first body segment 312, thereby improving the power generation efficiency of the back contact battery 77. The effect of the fourth body segment 321 is the same as that of the second body segment 311, and will not be described in detail here.

[0087] In some embodiments, such as Figure 3 As shown, the second body segments 311 on both sides of the midpoint of the first body segment 312 are inclined in opposite directions in the second direction Y;

[0088] The fourth body segments 321 on both sides of the midpoint of the third body segment 322 are inclined in the opposite direction in the second direction Y.

[0089] In this embodiment, the second body segment 311 is disposed on both sides of the first body segment 312 along the first direction X. Since the second body segments 311 on both sides of the midpoint of the first body segment 312 are inclined in opposite directions along the second direction Y, the second body segments are symmetrically distributed in both the first and second directions. This allows for maximum coverage of the power generation area of ​​the back contact battery 77, and the symmetrical structural design helps improve the strength of the back contact battery 77. The effect of the fourth body segment 321 is the same as that of the second body segment 311, and will not be described in detail here.

[0090] In some embodiments, the first gate line 31 includes 200 to 500 second body segments 311, and the second gate line 32 includes 200 to 500 fourth body segments 321.

[0091] In this embodiment, when the number of second body segments 311 on the first grid line 31 is too small, the current collection network formed by the second body segments 311 is too sparse, resulting in a large number of uncovered charge collection blind areas on the surface of the back contact battery 77, leading to charge waste and low power generation efficiency of the back contact battery 77. When the number of second body segments 311 on the first grid line 31 is too large, the second body segments 311 are excessively densely arranged in a limited area. Too many second body segments 311 increase the resistance loss of current, reducing the power generation efficiency of the back contact battery 77. Moreover, too many second body segments 311 will also occupy the surface space of the back contact battery 77, obstructing the surface and thus affecting the efficiency of the back contact battery 77. In this embodiment, when the number of second body segments 311 is controlled within the range of 200 to 500, the second body segments 311 form a denser current collection network, reducing the charge capture blind areas of the back contact battery 77. Furthermore, the resistance loss generated by the second body segments 311 is small, and the increase in current collection is negligible compared to increasing the number of second body segments 311. This improves the power generation efficiency and current collection efficiency of the back contact battery 77. Similarly, the effect of the fourth body segment 321 is the same as that of the second body segment 311, and will not be described in detail here.

[0092] Specifically, the distance between adjacent second body segments 311 is between 0.3mm and 0.8mm. For example, the distance between adjacent second body segments 311 can be: 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc.

[0093] The distance between adjacent fourth body segments 321 is between 0.3mm and 0.8mm. For example, the distance between adjacent fourth body segments 321 can be 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc.

[0094] When the spacing between adjacent second body segments 311 is too small, the excessively dense arrangement of the adjacent second body segments 311 will obstruct the surface of the back contact battery 77, affecting its efficiency. Simultaneously, an excessively dense arrangement of second body segments 311 is inconvenient to manufacture, increasing production costs. When the spacing between adjacent second body segments 311 is too large, the sparse arrangement of the second body segments 311 results in numerous charge collection blind spots on the back contact battery 77, reducing its efficiency. In this embodiment, the distance between adjacent second body segments 311 is between 0.3mm and 0.8mm, and the density of the second body segments 311 is moderate, covering most of the surface area of ​​the back contact battery 77, reducing charge collection blind spots, and avoiding wasted performance due to excessive density, thus improving the power generation efficiency of the back contact battery 77. Similarly, the effect of the fourth body segment 321 is the same as that of the second body segment 311, and will not be described in detail here.

[0095] The back contact battery 77 in the above embodiments further includes a doped region 2, such as Figure 4 As shown, the doped region 2 is disposed on the substrate 1. The doped region 2 includes a first polar doped region 21 and a second polar doped region 22. The polarities of the first polar doped region 21 and the second polar doped region 22 are opposite. The isolation region 6 is located between the first polar doped region 21 and the second polar doped region 22. The first gate line 31 is disposed in the first polar doped region 21, and the second gate line 32 is disposed in the second polar doped region 22.

[0096] In the prior art, the back contact battery 77 has a first polarity doped region 21 and a second polarity doped region 22 on its back side, with a positive electrode and a negative electrode formed on the first polarity doped region 21 and the second polarity doped region 22, respectively. Grid lines 3 are disposed on the first polarity doped region 21 or the second polarity doped region 22 to collect currents of different polarities. To insulate the grid lines 3 with different polarities, an insulating layer is provided at the ends of the grid lines 3 that are close to the opposite polarity grid lines 3 to avoid short circuits caused by the connection of grid lines 3 with different polarities. Typically, the grid lines 3 with different polarities are interlaced, causing the first polarity doped region 21 and the second polarity doped region 22 to also interlaced and form a long, thin structure. This makes them prone to cross-doping during production, resulting in a decrease in the power generation efficiency of the back contact battery 77.

[0097] In this embodiment, the first gate line 31 and the second gate line 32, which have different polarities, are both disposed within a rectangular area. That is, the first polarity doped region 21 and the second polarity doped region 22 can be arranged in a rectangular shape, and the isolation region 6 is located between the first polarity doped region 21 and the second polarity doped region 22. The structure is clear and facilitates the production and manufacturing of the doped regions 2. This reduces the possibility of mutual interference between different doped regions 2 and improves the stability and reliability of power generation of the back contact battery 77.

[0098] In some embodiments, such as Figure 2 As shown, the dimension of the isolation zone 6 along the first direction X is d1, which satisfies 0.03mm≤d1≤0.15mm. For example, d1 can be: 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm.

[0099] When the dimension d1 of the isolation region 6 along the first direction X is small, the distance between the first polar doped region 21 and the second polar doped region 22 on both sides of the isolation region 6 is too close. During the production process, the first polar doped region 21 and the second polar doped region 22 are prone to mixing, which can cause the grid lines 3 set on the doped regions 2 with different polarities to short-circuit, reducing the power generation efficiency of the back contact battery 77. When the dimension d1 of the isolation region 6 along the first direction X is large, the isolation region 6 occupies too large a surface area of ​​the back contact battery 77, making the area that can generate electricity smaller, resulting in a decrease in the power generation efficiency of the back contact battery 77. In this embodiment, the dimension d1 of the isolation region 6 along the first direction X is limited to 0.03mm to 0.15mm to ensure effective isolation between the first doped region 2 and the second doped region 2, while not occupying too large an area, ensuring that the back contact battery 77 has enough area for power generation, and improving the power generation efficiency and operational stability of the back contact battery 77.

[0100] In some embodiments, such as Figure 2 As shown, the minimum spacing between the grid line 3 and the isolation area 6 is d2, which satisfies 0.05mm≤d2≤0.3mm. For example, d2 can be: 0.03mm, 0.06mm, 0.08mm, 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, or 0.3mm.

[0101] When the distance d2 between the grid line 3 and the isolation region 6 is too small, the grid lines 3 on both sides of the isolation region 6 are too close together. This can easily lead to breakdown when the current is too high, damaging the back contact battery 77 and affecting its power generation efficiency. When the distance d2 between the grid line 3 and the isolation region 6 is too large, a large open area is created between the isolation region 6 and the grid line 3. The charge generated in this area cannot be effectively collected by the grid line 3, resulting in wasted power generation performance and reduced power generation efficiency of the back contact battery 77. In this embodiment, the minimum distance d2 between the grid line 3 and the isolation region 6 is limited to 0.05mm to 0.3mm. This allows the grid line 3 to collect charge in as much area as possible while preventing breakdown of the grid lines 3 on both sides of the isolation region 6, thus improving the power generation efficiency of the back contact battery 77 and ensuring its operational stability.

[0102] This application embodiment also provides a back-contact stacked battery 7, such as Figure 5 As shown, the back-contact tandem solar cell 7 includes a top cell and a bottom cell electrically connected to each other. The top cell is a perovskite cell 78, and the bottom cell is a back-contact cell 77, wherein the back-contact cell 77 can be any of the back-contact cell 77 involved in the above embodiments. The back-contact tandem solar cell 7 can be a three-terminal tandem solar cell. When processing the back-contact tandem solar cell 7, the top cell and the bottom cell can be connected by directly depositing the perovskite top cell on the bottom cell. Compared with single-crystal silicon solar cells, the back-contact tandem solar cell 7 has higher efficiency and power generation. Moreover, the back-contact tandem bottom cell using the back-contact cell 77 as the bottom cell has advantages such as no current mismatch, high process tolerance, and wide application scenarios. At the same time, compared with two-terminal tandem solar cells, the three-terminal tandem solar cell formed by the perovskite cell 78 and the back-contact cell 77 can have an additional electrode to output the mismatch current, which is beneficial to ensure that the back-contact tandem solar cell 7 can operate at a relatively higher power, and the required voltage matching is less affected by changes in the solar spectrum than the current. When the back-contact cell 77 is used as the bottom cell, a two-terminal series structure can be constructed by using electrodes with opposite contact polarities, enabling a conversion from three-terminal to two-terminal operation. The back-contact cell 77 has a textured surface, allowing for conformal deposition and growth of perovskite, which improves the utilization of incident light. The back-contact tandem cell 7, made using the perovskite cell 78 and the back-contact cell 77, eliminates the need for current matching and exhibits high tolerance for perovskite bandgap and thickness. The three-terminal back-contact tandem cell 7 has a wider range of applications, achieving high-power operation in various outdoor environments, better meeting practical usage needs.

[0103] like Figure 6As shown, in one possible embodiment, the back contact stacked battery 7 consists of, from top to bottom, a protective layer 71, a transparent conductive layer 72, an electron transport layer 73, a perovskite layer 74, a hole transport layer 75, a composite layer 76, and a back contact battery 77. The transparent conductive layer 72 (transparent conductive oxide, TCO) can be an indium tin oxide layer.

[0104] The above descriptions are merely specific implementations of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A back-contact battery, characterized in that, include: Base (1); A grid line (3) is disposed on the substrate (1). An isolation zone (6) is disposed on the substrate (1); The gate line (3) includes a first gate line (31) and a second gate line (32), which are spaced apart along a first direction (X). The first gate line (31) and the second gate line (32) have different polarities. The isolation region (6) is located between the first gate line (31) and the second gate line (32). The first gate line (31) includes a first body segment (312) and a plurality of second body segments (311) that are connected to each other. The first body segment (312) extends along a second direction (Y). Each of the second body segments (311) The second body segment (311) is spaced apart along the second direction (Y) and at least a portion of the second body segment (311) is inclined relative to the first body segment (312). The second grid line (32) includes interconnected third body segments (322) and a plurality of fourth body segments (321). The third body segment (322) extends along the second direction (Y) and each of the fourth body segments (321) is spaced apart along the second direction (Y) from the third body segment (322). At least a portion of the fourth body segment (321) is inclined relative to the third body segment (322).

2. The back contact battery according to claim 1, characterized in that, The angle between the second body segment (311) and the first direction (X) is a, and 0° < a ≤ 10°; The angle between the fourth body segment (321) and the first direction (X) is b and 0° < b ≤ 10°.

3. The back contact battery according to claim 2, characterized in that, The second body segments (311) located on opposite sides of the same first body segment (312) along the first direction (X) have opposite inclination directions; The fourth body segment (321) located on opposite sides of the same third body segment (322) along the first direction (X) has the opposite tilt direction.

4. The back contact battery according to claim 1, characterized in that, In the second body segment (311) disposed along the second direction (Y) in the same first body segment (312), the tilt direction of at least one second body segment (311) is opposite to the tilt direction of the other second body segments (311); In the fourth body segment (321) disposed along the second direction (Y) in the same third body segment (322), at least one of the fourth body segments (321) has an inclination direction opposite to that of the other second body segments (311).

5. The back contact battery according to claim 1, characterized in that, The first gate line (31) includes 200 to 500 second body segments (311), the second gate line (32) includes 200 to 500 fourth body segments (321), and / or; The distance between adjacent second body segments (311) is 0.3 mm to 0.8 mm, and the distance between adjacent fourth body segments (321) is 0.3 mm to 0.8 mm.

6. The back contact battery according to any one of claims 1 to 5, characterized in that, The back contact battery (77) further includes a doped region (2), which is disposed on the substrate (1). The doped region (2) includes a first polar doped region (21) and a second polar doped region (22). The polarity of the first polar doped region (21) and the second polar doped region (22) are opposite. The isolation region (6) is located between the first polar doped region (21) and the second polar doped region (22). The first grid line (31) is disposed in the first polar doped region (21), and the second grid line (32) is disposed in the second polar doped region (22).

7. The back contact battery according to any one of claims 1 to 5, characterized in that, The isolation zone (6) has a dimension d1 along the first direction (X) that satisfies 0.03mm≤d1≤0.15mm.

8. The back contact battery according to any one of claims 1 to 5, characterized in that, The minimum spacing between the grid line (3) and the isolation area (6) is d2, which satisfies 0.05mm≤d2≤0.3mm.

9. A back-contact stacked battery, characterized in that, The back-contact stacked battery includes a top battery and a bottom battery connected to each other. The top battery is a perovskite battery, and the bottom battery is a back-contact battery (77). The back-contact battery (77) is the back-contact battery (77) according to any one of claims 1 to 8.

10. A photovoltaic module, characterized in that, The photovoltaic module includes at least one battery string, the battery string including a back-contact battery (77) according to any one of claims 1 to 8 or a back-contact tandem battery (7) according to claim 9.

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