Back contact solar cell and photovoltaic module

Abstract

The application discloses a back contact type battery piece and a photovoltaic module, and belongs to the technical field of photovoltaic modules. The battery piece comprises a battery piece body, the first surface of the battery piece body is provided with first fine grids and second fine grids which are arranged alternately and spaced apart along a first direction and a second direction, the area of the battery piece body close to the first side edge or the second side edge is an edge area, and the area of the battery piece body relatively far from the first side edge or the second side edge is a middle area; a first solder pad is arranged in the edge area, the first solder pad is connected with at least one first fine grid, at least one second fine grid closest to the first side edge or the second side edge in at least one edge area is a first sub-fine grid, and the first sub-fine grid is disconnected at the extension of the first solder pad along the second direction; the battery piece body comprises a doped layer, the doped layer comprises a second doped layer, the second doped layer is arranged correspondingly to the second fine grid, and the second doped layer below the disconnection of the first sub-fine grid is continuous.

Description

Technical Field

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

[0002] Back-contact photovoltaic (PV) modules, as a type of PV module, are characterized by high photoelectric conversion efficiency and aesthetically pleasing appearance. A back-contact PV module includes solar cells. On the back of each solar cell are a first grid and a second grid, extending along a first direction and alternately arranged along a second direction, to collect charge carriers generated by the solar cell.

[0003] In related technologies, back-contact photovoltaic modules also include a first solder strip and a second solder strip. Both the first and second solder strips extend along a second direction and are alternately arranged along a first direction on the back of the solar cell. The first solder strip is connected to a pad on the first grid, and the second solder strip is connected to a pad on the second grid. This allows the first solder strip to collect the charge carriers gathered by the first grid, and the second solder strip to collect the charge carriers gathered by the second grid, and then transmit the collected charge carriers to an external circuit. To prevent short circuits in the photovoltaic module, a first insulating block is provided between the first solder strip and the second grid, and a second insulating block is provided between the second solder strip and the first grid. The first and second solder strips need to span two adjacent solar cells to connect at least two adjacent solar cells in series, forming a cell string.

[0004] However, when the first solder strip is connected in series with two adjacent solar cells, the first solder strip needs to cross the second grid at the outermost edge of the two adjacent solar cells. During the process of soldering the first solder strip to the solar cell, or during the lamination of the photovoltaic module, the second grid at the outermost edge can easily pierce the first insulating block and become electrically connected to the first solder strip, causing the first solder strip to become electrically connected to the second grid, resulting in a partial short circuit in the photovoltaic module. Utility Model Content

[0005] This application discloses a back-contact solar cell and a photovoltaic module to solve, or at least partially solve, the problem in the related technology where the outermost second grid easily pierces the first insulating block, the first solder strip is electrically connected to the second grid, and the photovoltaic module experiences a partial short circuit.

[0006] To solve the above-mentioned technical problems, this application is implemented as follows:

[0007] In a first aspect, this application discloses a back-contact solar cell, the solar cell comprising a solar cell body having a first surface and a second surface disposed opposite to each other, the first surface being provided with a first grid and a second grid extending along a first direction and alternately arranged along a second direction, the solar cell body having a first side and a second side disposed opposite to each other along the second direction, the area of ​​the solar cell body near the first side or the second side being an edge region, the area of ​​the solar cell body relatively far from the first side or the second side being an intermediate region, the second direction intersecting the first direction; a first pad being provided in the edge region, the first pad connecting at least one first grid, at least one second grid closest to the first side or the second side in at least one edge region being a first sub-grid, the first sub-grid being disconnected at the extension of the first pad along the second direction; the solar cell body including a doped layer, the doped layer including a second doped layer, the second doped layer being disposed corresponding to the second grid, the second doped layer below the disconnection of the first sub-grid being continuous.

[0008] In some embodiments, in the intermediate region, the first fine grid extends through the cell body along the first direction; and / or, in the intermediate region, the second fine grid extends through the cell body along the first direction.

[0009] In some embodiments, a first main gate extending along the second direction is provided in the intermediate region; the first main gate is electrically connected to the first fine gate, and a first insulating block is provided between the first main gate and the second fine gate.

[0010] In some embodiments, the width of the first sub-grid break along the first direction is L1, satisfying 1mm≤L1≤5mm.

[0011] In some embodiments, a second insulating block is provided at the break point of the first sub-grid, the length of the second insulating block along the first direction is L2, satisfying L2≥L1; and / or, the second insulating block covers the end of the first sub-grid near the break point.

[0012] In some embodiments, a first end line is further provided in the edge region, the first end line is connected to the side of the first pad near the first side or the second side, and the first end line is connected to the first fine gate; the second fine gate in the edge region that is relatively far away from the first side or the second side is a second sub-fine gate, and the second sub-fine gate is broken at the first end line; or, the second sub-fine gate extends along the first direction, and a third insulating block is provided at the intersection with the first end line.

[0013] In some embodiments, the doped layer further includes a first doped layer, which is disposed corresponding to the first fine gate, and the second doped layer below the second sub-fine gate is disposed intermittently, and the second doped layer below the second sub-fine gate and the first doped layer have an interdigitated structure; or, the second doped layer below the second sub-fine gate is disposed continuously, and the second doped layer below the second sub-fine gate and the first doped layer both extend along the first direction and are arranged alternately along the second direction.

[0014] In some embodiments, the first sub-grid is the second grid closest to the first side or the second side within the edge region; the sum of the number of the first grid and the second grid is N, and when N is odd, the breaks in the two edge regions are arranged opposite each other along the second direction, and when N is even, the breaks in the two edge regions are staggered along the second direction.

[0015] In some embodiments, the first end wire includes one sub-end wire, two sub-end wires, or three sub-end wires.

[0016] Secondly, this application also discloses a photovoltaic module, the photovoltaic module comprising at least two back-contact solar cells as described in the above embodiments, the at least two solar cells being arranged sequentially along the second direction; a first solder strip extending along the second direction and connecting the edge regions of two adjacent solar cells that are close to each other, the first solder strip passing through the break of the first sub-grid.

[0017] In some embodiments, the width of the break along the first direction is L1, and the width of the first solder strip along the first direction is L3, satisfying 1.5*L3≤L1≤10*L3.

[0018] This application discloses a back-contact solar cell and a photovoltaic module. The solar cell includes a cell body with a first surface and a second surface disposed opposite to each other. The first surface is provided with a first grid and a second grid that extend along a first direction and are alternately arranged along a second direction. Along the second direction, the cell body has a first side and a second side that are disposed opposite to each other. The area of ​​the cell body near the first side or the second side is an edge region, and the area of ​​the cell body relatively far from the first side or the second side is a middle region. The second direction intersects the first direction. A first pad is provided in the edge region, and the first pad connects to at least one of the first grids. At least one second grid closest to the first side or the second side in at least one edge region is a first sub-grid. The first sub-grid is disconnected at the extension of the first pad along the second direction. The cell body includes a doped layer, and the doped layer includes a second doped layer. The second doped layer is disposed corresponding to the second grid, and the second doped layer below the disconnection of the first sub-grid is continuous.

[0019] The back-contact solar cell disclosed in this application has a first fine grid and a second fine grid arranged alternately along a second direction on the first surface of the solar cell body, so as to collect the charge carriers generated by the solar cell body through the first fine grid and the second fine grid.

[0020] Furthermore, a first pad is provided in the edge region of the solar cell, and at least one first fine grid is connected through the first pad to connect the at least one first fine grid to the first solder strip, so that the carriers collected by the at least one first fine grid are transferred to the external circuit through the first solder strip. At least one second fine grid closest to the first or second side in at least one edge region is a first sub-fine grid. The first sub-fine grid is disconnected at the extension of the first pad along the second direction to prevent the second fine grid from piercing the insulating block, causing the second fine grid and the first solder strip to conduct, resulting in a partial short circuit in the photovoltaic module and affecting the photoelectric conversion efficiency of the photovoltaic module.

[0021] Furthermore, the solar cell body also includes a doped layer, which includes a second doped layer, and the second doped layer is disposed corresponding to the second fine grid. The second doped layer is continuously disposed below the break in the first fine grid to collect the charge carriers generated by the solar cell body, thereby ensuring the collection efficiency of the solar cell charge carriers. Attached Figure Description

[0022] Figure 1 This diagram illustrates the structure of the back-contact battery cell described in the embodiments of this application. Figure 1 ;

[0023] Figure 2This diagram illustrates the structure of the back-contact battery cell described in the embodiments of this application. Figure 2 ;

[0024] Figure 3 This diagram illustrates the structure of the back-contact battery cell described in the embodiments of this application. Figure 3 ;

[0025] Figure 4 This is a schematic diagram of the structure of the photovoltaic module described in the embodiments of this application.

[0026] Figure 5 This represents a cross-sectional view of the photovoltaic module described in the embodiments of this application.

[0027] Figure label:

[0028] 10: Cell body; 11: First grid; 12: Second grid; 121: First sub-grid; 122: Break; 123: Second sub-grid; 13: First side; 14: Second side; 15: First doped layer; 16: Second doped layer;

[0029] 20: First pad;

[0030] 30: First main gate;

[0031] 40: First insulating block;

[0032] 50: Second insulating block;

[0033] 60: Third insulating block;

[0034] 70: First end line;

[0035] 80: First weld strip;

[0036] A: Edge region; B: Middle region;

[0037] X: First direction; Y: Second direction. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the fixed scope of the present utility model.

[0039] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0040] This application discloses a back-contact battery cell, which includes a battery cell body 10. The battery cell body 10 has a first surface and a second surface disposed opposite to each other. The first surface is provided with a first fine grid 11 and a second fine grid 12 that extend along a first direction X and are alternately spaced along a second direction Y. Along the second direction Y, the battery cell body 10 has a first side 13 and a second side 14 disposed opposite to each other. The area of ​​the battery cell body 10 close to the first side 13 or the second side 14 is the edge region A, and the area of ​​the battery cell body 10 relatively far from the first side 13 or the second side 14 is the middle region. Domain B, the second direction Y intersects with the first direction X; a first pad 20 is provided in the edge region A, the first pad 20 is connected to at least one first fine gate 11, at least one second fine gate 12 in at least one edge region A that is closest to the first side 13 or the second side 14 is a first sub-fine gate 121, the first sub-fine gate 121 is broken at the extension of the first pad 20 along the second direction Y; the cell body 10 includes a doped layer, the doped layer includes a second doped layer 16, the second doped layer 16 is correspondingly provided with the second fine gate 12, and the second doped layer 16 below the break 122 of the first sub-fine gate 121 is continuous.

[0041] This application discloses a back-contact solar cell, in which both the positive and negative grid lines are located on the back side of the solar cell to prevent the front side of the solar cell from being blocked by the grid lines, thereby improving the photoelectric conversion efficiency of the solar cell.

[0042] like Figure 1 As shown, the back-contact solar cell disclosed in this application includes a cell body 10. The cell body 10, as the core component of the solar cell, can convert solar energy into electrical energy. The cell body 10 has a first surface and a second surface arranged opposite to each other. When the first surface is the front side of the cell body 10, i.e., the light-receiving surface facing sunlight, the second surface is the back side of the cell body 10, i.e., the back-shielded surface facing away from sunlight. When the first surface is the back side of the cell body 10, i.e., the back-shielded surface facing away from sunlight, the second surface is the front side of the cell body 10, i.e., the light-receiving surface facing sunlight.

[0043] The following description will use the example of the back surface of the battery cell body 10 and the front surface of the battery cell body 10 as an example to illustrate the back contact battery cell disclosed in the embodiments of this application.

[0044] On the plane containing the battery cell body 10, the battery cell has intersecting first direction X and second direction Y. When the battery cell body 10 is a rectangular battery cell, the first direction X can be the length direction of the battery cell body 10, and the second direction Y can be the width direction of the battery cell body 10. Alternatively, the first direction X can be the width direction of the battery cell body 10, and the second direction Y can be the length direction of the battery cell body 10.

[0045] The following will use the first direction X as the length direction of the battery cell body 10 and the second direction Y as the width direction of the battery cell body 10 as an example to describe the battery cell disclosed in this application.

[0046] like Figure 1 and Figure 2 As shown, the first surface of the battery cell body 10 is provided with a first fine grid 11 and a second fine grid 12 extending along a first direction X and arranged alternately along a second direction Y. The polarities of the first fine grid 11 and the second fine grid 12 are opposite. That is, when the first fine grid 11 is a positive grid line, the second fine grid 12 is a negative grid line, and when the first fine grid 11 is a negative grid line, the second fine grid 12 is a positive grid line. This allows the carriers generated by the battery cell body 10 to be collected through the first fine grid 11 and the second fine grid 12.

[0047] It should be noted that, as Figure 3 As shown, the battery cell body 10 in this embodiment is a rectangular battery cell. Along the second direction Y, the battery cell body 10 has a first side 13 and a second side 14 disposed opposite to each other. The area of ​​the battery cell body 10 close to the first side 13 or the second side 14 is the edge region A, and the area of ​​the battery cell body 10 relatively far away from the first side 13 and the second side 14 is the middle region B.

[0048] For example, along the second direction Y, the battery cell body 10 has an edge region A near the first side 13, a middle region B, and an edge region A near the second side 14. That is, along the second direction Y, the battery cell body 10 has an edge region A, a middle region B, and an edge region A arranged sequentially.

[0049] Combination Figure 1 , Figure 2 and Figure 4As shown, a first pad 20 is provided in the edge region A of the battery cell body 10. The first pad 20 is connected to at least one first fine gate 11. The first solder ribbon 80 is connected to at least one first fine gate 11 through the first pad 20, so that the charge carriers collected by at least one first fine gate 11 can be collected through the first solder ribbon 80 and the collected charge carriers can be transmitted to the external circuit.

[0050] For example, such as Figure 1 As shown, the first pad 20 connects only one first fine gate 11. Of course, the first pad 20 can connect two adjacent first fine gates 11 along the second direction Y, three adjacent first fine gates 11 along the second direction Y, or four adjacent first fine gates 11 along the second direction Y. In this embodiment, the specific number of first fine gates 11 connected to the first pad 20 is not limited. In practical applications, those skilled in the art can set it as needed.

[0051] It should be noted that at least one second fine grid 12 closest to the first side 13 or the second side 14 within at least one edge region A is a first sub-fine grid 121. The first sub-fine grid 121 is disconnected at the extension of the first pad 20 along the second direction Y to avoid the second fine grid 12 piercing the insulating block, causing the second fine grid 12 and the first solder strip 80 to conduct, resulting in a local short circuit in the photovoltaic module and affecting the photoelectric conversion efficiency of the photovoltaic module.

[0052] That is, at least one second fine gate 12 closest to the first side 13 in the edge region A near the first side 13 is a first sub-fine gate 121, and / or, at least one second fine gate 12 closest to the second side 14 in the edge region A near the second side 14 is a first sub-fine gate 121.

[0053] It should be noted that if the number of main grids in the solar cell 10 is even, the cells can be interconnected simply by rotating them 180°. When only in the edge region A closest to the first side 13 or the second side 14, at least one second grid 12 is a first sub-grid 121 with a break 122, meaning only one edge region A in the solar cell 10 has a break in its first sub-grid 121, then to meet the interconnection requirements, the solar cell 10 needs to distinguish between A and B cells. If in the solar cell 10, in both edge regions A, at least one second grid 12 closest to the first side 13 or the second side 14 is a first sub-grid 121 with a break 122, meaning both edge regions A in the solar cell 10 have breaks, then the solar cell 10 meets the interconnection requirements and does not need to distinguish between A and B cells, simplifying the photovoltaic module manufacturing process.

[0054] The first sub-grid 121 is interrupted at the extension of the first pad 20 along the second direction Y. It can be understood that the first sub-grid 121 comprises multiple segments, each extending along the first direction X and spaced apart. A gap exists between adjacent first sub-grids 121, which serves as the interruption point 122 of the first sub-grid 121. The extension of the first pad 20 along the second direction Y passes through this interruption point 122. This interruption point 122 prevents the first solder strip 80 and the second grid 12 from becoming conductive, thus avoiding a partial short circuit in the photovoltaic module and affecting its photoelectric conversion efficiency.

[0055] It should be noted that, as Figure 1 and Figure 2 As shown, the solar cell body 10 includes a substrate and doped layers stacked on the substrate. The doped layers include a first doped layer 15 and a second doped layer 16. The first doped layer 15 and the second doped layer 16 both extend along a first direction X and are arranged alternately along a second direction Y. There is an isolation region between adjacent first doped layers 15 and second doped layers 16. The isolation region can isolate and insulate adjacent first doped layers 15 and second doped layers 16 to avoid the adjacent first doped layers 15 and second doped layers 16 from conducting, which would cause a local short circuit in the solar cell and affect the photoelectric conversion efficiency of the solar cell.

[0056] The first fine gate 11 is disposed corresponding to the first doped layer 15, and the second fine gate 12 is disposed corresponding to the second doped layer 16. That is, the first fine gate 11 is disposed on the side of the first doped layer 15 away from the substrate, and the second fine gate 12 is disposed on the side of the second doped layer 16 away from the substrate, so that the carriers collected by the first doped layer 15 are collected through the first fine gate 11, and the carriers collected by the second doped layer 16 are collected through the second fine gate 12.

[0057] like Figure 1 and Figure 2 As shown, the second doped layer 16 below the break 122 of the first sub-grid 121 is continuously arranged to collect the charge carriers generated by the cell body 10 through the second doped layer 16, thereby ensuring the collection efficiency of the cell charge carriers. That is, the first sub-grid 121 includes multiple discontinuous segments of the first sub-grid 121, while the second doped layer 16 corresponding to the first sub-grid 121 is a continuous structure without breaks. Compared to discontinuous arrangements of the second doped layer 16, the continuous arrangement of the second doped layer 16 increases the effective power generation area of ​​the second doped layer 16, which is beneficial for the generation and collection of charge carriers.

[0058] In some embodiments, such as Figure 1As shown, in the intermediate region B, the first fine grid 11 penetrates the battery cell body 10 along the first direction X; and / or, in the intermediate region B, the second fine grid 12 penetrates the battery cell body 10 along the first direction X.

[0059] like Figure 1 , 2 As shown, in the middle region B, the first fine grid 11 penetrates the cell body 10 along the first direction X, so as to collect the charge carriers generated in the middle region B of the cell body 10 through the first fine grid 11, thereby improving the collection efficiency of charge carriers in the middle region B of the cell body 10 and improving the photoelectric conversion efficiency of the cell.

[0060] Within the intermediate region B, a second fine grid 12 is inserted through the cell body 10 along the first direction X, so as to collect the charge carriers generated in the intermediate region B of the cell body 10 through the second fine grid 12, thereby improving the collection efficiency of charge carriers in the intermediate region B of the cell body 10 and improving the photoelectric conversion efficiency of the cell.

[0061] The above configuration also helps to simplify the arrangement of the first fine grid 11 and the second fine grid 12 in the middle region B, simplify the processing technology of the solar cells, reduce the processing cost of the solar cells, and enhance the market competitiveness of the solar cells.

[0062] It should be noted that, along the first direction X, the battery cell body 10 has a third side and a fourth side disposed opposite to each other. The first fine grid 11 penetrating the battery cell body 10 along the first direction X means that the first fine grid 11 extends from the third side to the fourth side of the battery cell body 10 along the first direction X. The second fine grid 12 penetrating the battery cell body 10 along the first direction X means that the second fine grid 12 extends from the third side to the fourth side of the battery cell body 10 along the first direction X.

[0063] In some embodiments, such as Figure 2 As shown, a first main grid 30 extending along the second direction Y is provided in the middle region B; the first main grid 30 is electrically connected to the first fine grid 11, and a first insulating block 40 is provided between the first main grid 30 and the second fine grid 12.

[0064] like Figure 2As shown, a first main grid 30 and a second main grid are arranged in the middle region B, extending along the second direction Y and alternately spaced along the first direction X. The first main grid 30 is electrically connected to multiple first fine grids 11 to collect the charge carriers collected by the first fine grids 11 and transmit them to an external circuit. A first insulating block 40 is provided between the first main grid 30 and each second fine grid 12. The first insulating block 40 isolates the first main grid 30 and the second fine grid 12 to prevent them from conducting and causing a partial short circuit in the solar cell, thus affecting the photoelectric conversion efficiency of the solar cell.

[0065] Similarly, the second main grid and multiple second fine grids 12 are electrically connected together to collect the charge carriers collected by the multiple second fine grids 12 through the second main grid and transfer the collected charge carriers to the external circuit. An insulating block is provided between the second main grid and each first fine grid 11 to isolate the second main grid and the first fine grid, so as to avoid the second main grid and the first fine grid being connected and causing a partial short circuit in the solar cell, which would affect the photoelectric conversion efficiency of the solar cell.

[0066] In some embodiments, such as Figure 1 As shown, the width of the first sub-grid 121 break 122 along the first direction X is L1, which satisfies 1mm≤L1≤5mm.

[0067] like Figure 1 As shown in the embodiment of this application, the width L1 of the first sub-fine gate 121 break 122 along the first direction X is set to be greater than or equal to 1 mm and less than or equal to 5 mm. For example, the width L1 of the first sub-fine gate 121 break 122 along the first direction X can be set to 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0068] If the width L1 of the first sub-grid 121 break 122 along the first direction X is less than 1mm, then the first sub-grid 121 break 122 along the first direction X is too narrow. When the first solder strip 80 passes through the first sub-grid 121 break 122, it is easy to contact and connect with the first sub-grid 121, resulting in a partial short circuit in the photovoltaic module and affecting the photoelectric conversion efficiency of the photovoltaic module.

[0069] If the width L1 of the first sub-grid 121 break 122 along the first direction X is greater than 5mm, it will affect the extension length of the first sub-grid 121 along the first direction X, affect the efficiency of the first sub-grid 121 in collecting charge carriers, and thus affect the photoelectric conversion efficiency of the solar cell.

[0070] In some embodiments, such as Figure 2As shown, a second insulating block 50 is provided at the break point 122 of the first sub-grid 121. The length of the second insulating block 50 along the first direction X is L2, which satisfies L2≥L1; and / or, the second insulating block 50 covers the end of the first sub-grid 121 near the break point 122.

[0071] like Figure 1 The solar cell 10 shown can be a TBC (TOPCon back contact) solar cell. The surface of this solar cell 10 has a dielectric layer, which is itself non-conductive. The second grid needs to penetrate the dielectric layer and form an electrical connection with the underlying second doped layer. Furthermore, the solder ribbon does not have burn-through capability; that is, the dielectric layer can insulate the first solder ribbon 80 and the second doped layer 16, and the first solder ribbon 80 will not burn through the dielectric layer to form a connection with the second doped layer 16. Therefore, as long as the first sub-grid 121 has a break 122, even if the first solder ribbon 80 passes through the break 122, the first solder ribbon 80 will not form a connection with the second grid 12. Figure 1 The second insulating block 50 may not be required at the break point of the first sub-grid 121 in the battery cell 10 shown.

[0072] like Figure 2 The solar cell 10 shown can be a hybrid back-contact solar cell (HJT-TOPCon BC) with a TCO conductive layer on its surface. Since the TCO conductive layer is conductive, a second insulating block 50 needs to be placed at the break point of the first sub-grid 121. The second insulating block 50 isolates the first solder ribbon 80 and the second doped layer 16 to prevent the first solder ribbon 80 and the second doped layer 16 from conducting, which could lead to a partial short circuit in the photovoltaic module and affect its photoelectric conversion efficiency. Furthermore, to further reduce costs, both the first grid 11 and the second grid 12 of the hybrid back-contact solar cell can be prepared using low-temperature paste. For example, at least one of low-temperature silver paste, low-temperature silver-coated copper paste, or low-temperature copper paste can be used. Low-temperature pastes do not have burn-through properties; therefore, the first grid 11 is conductive to the first doped layer 15 through the TCO conductive layer, and the second grid 12 is conductive to the second doped layer 16 through the TCO conductive layer. It is understood that... Figure 1 Alternatively, a hybrid back-contact cell can be used. In this case, a second insulating block 50 needs to be set at the break point of the first sub-grid 121. The second insulating block 50 is used to insulate and isolate the first solder strip 80 and the second doped layer 16 to prevent the first solder strip 80 and the second doped layer 16 from conducting, which would cause a local short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0073] It should be noted that low-temperature pastes are typically composed of spherical powder and sheet powder. Compared to spherical powder, sheet powder has a larger size, while traditional high-temperature silver pastes contain only spherical powder. Compared to pure spherical powder, the combination of sheet powder and spherical powder results in a rougher surface. Furthermore, high-temperature silver pastes require a high-temperature process to burn through the dielectric layer to form contact with the doped layer. The spherical powder melts at high temperatures, resulting in fewer barbs on the grid line surface. In contrast, low-temperature pastes are cured at low temperatures, and the spherical and sheet powders do not melt during the low-temperature process, resulting in a rougher grid line surface with more barbs. Therefore, when the solar cell 10 uses a low-temperature paste to prepare the fine grid, barbs are more likely to form, increasing the risk of the second fine grid 12 piercing the insulating block. It is understandable that both high-temperature and low-temperature pastes form the grid lines through screen printing or stencil printing. During the printing process, the paste viscosity increases, further increasing the surface roughness of the grid lines and thus forming barbs.

[0074] like Figure 2 As shown, a second insulating block 50 is provided within the break 122 of the first sub-grid 121. The length L2 of the second insulating block 50 along the first direction X is set to be greater than or equal to the width L1 of the break 122 of the first sub-grid 121 along the first direction X. This is to insulate and isolate the second doped layer 16 and the first solder ribbon 80 of the cell body 10 through the second insulating block 50, preventing the second doped layer 16 and the first solder ribbon 80 of the cell body 10 from becoming conductive, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0075] For example, L2 = L1; or, L2 = 1.1 * L1; or, L2 = 1.2 * L1; or, L2 = 1.3 * L1; or, L2 = 1.4 * L1; or, L2 = 1.5 * L1.

[0076] like Figure 2 As shown in the embodiment of this application, the second insulating block 50 covers the end of the first sub-grid 121 near the break 122 to further prevent the first sub-grid 121 and the first solder strip 80 from conducting, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0077] In some embodiments, a first end line 70 is further provided in the edge region A. The first end line 70 is connected to the side of the first pad 20 near the first side 13 or the second side 14, and the first end line 70 is connected to the first fine gate 11. The second fine gate 12 in the edge region A that is relatively far from the first side 13 or the second side 14 is a second sub-fine gate 123, such as... Figure 1 As shown, the second sub-grid 123 is broken at the first end line 70; or, as Figure 2 As shown, the second sub-grid 123 extends along the first direction X, and a third insulating block 60 is provided at the intersection with the first end line 70.

[0078] like Figure 1 and Figure 2 As shown, a first end line 70 is provided in the edge region A of the battery cell body 10. The first end line 70 is connected to the side of the first pad 20 near the first side 13, or the first end line 70 is connected to the side of the first pad 20 near the second side 14. Furthermore, the first end line 70 is connected to multiple first fine grids 11. The first end line 70 collects the charge carriers collected by the multiple first fine grids 11 in the edge region, and the collected charge carriers are transferred to the first solder strip 80 through the first pad 20, and then transferred to the external circuit through the first solder strip 80.

[0079] It should be noted that, in the embodiments of this application, at least one second fine grid 12 in the edge region A of the battery cell body 10 that is close to the first side 13 or the second side 14 is the first sub-fine grid 121, while the second fine grid 12 in the edge region A of the battery cell body 10 that is relatively far away from the first side 13 or the second side 14 is the second sub-fine grid 123.

[0080] Taking the edge region A located near the first side 13 of the battery cell body 10 as an example, the second fine grid 12 in the edge region A includes a first sub-fine grid 121 and a second sub-fine grid 123. The first sub-fine grid 121 is at least one second fine grid 12 located in the edge region A near the first side 13, and the second sub-fine grid 123 is a second fine grid 12 located in the edge region A relatively far away from the first side 13.

[0081] like Figure 1 As shown, the second sub-grid 123 is disconnected at the first end line 70 to prevent the first end line 70 and the second sub-grid 123 from being connected, which would cause a local short circuit in the solar cell and affect the photoelectric conversion efficiency of the solar cell.

[0082] like Figure 2 As shown, a third insulating block 60 is provided at the intersection of the second sub-grid 123 and the first end line 70 to insulate and isolate the second sub-grid 123 and the first end line 70, so as to prevent the second sub-grid 123 and the first end line 70 from conducting, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0083] In some embodiments, such as Figure 1 As shown, the doped layer further includes a first doped layer 15, which is disposed corresponding to the first fine gate 11. A second doped layer 16 is intermittently disposed below the second sub-fine gate 123, and the second doped layer 16 below the second sub-fine gate 123 and the first doped layer 15 form an interdigitated structure; or, as shown... Figure 2As shown, the second doped layer 16 below the second sub-gate 123 is continuously disposed. The second doped layer 16 and the first doped layer 15 below the second sub-gate 123 both extend along the first direction X and are arranged alternately along the second direction Y.

[0084] The solar cell in this embodiment includes a doped layer, which includes a first doped layer 15 and a second doped layer 16. A first fine grid 11 and a first doped layer 15 are correspondingly disposed, and a second fine grid 12 and a second doped layer 16 are correspondingly disposed.

[0085] like Figure 1 As shown, within edge region A, the second doped layer 16 below the second sub-grid 123 is intermittently arranged, and the first doped layer 15 below the first grid 11 is also intermittently arranged. That is, within edge region A, the second doped layer 16 and the first doped layer 15 below the second sub-grid 123 form an interdigitated structure. Correspondingly, the first grid 11 and the second sub-grid 123 also form an interdigitated structure. This prevents the first terminal line 70 and the second sub-grid 123 from contacting and conducting, thus avoiding a local short circuit in the solar cell and affecting its photoelectric conversion efficiency.

[0086] like Figure 2 As shown, within edge region A, the second doped layer 16 below the second sub-grid 123 is continuously disposed, and the first doped layer 15 below the first grid 11 is also continuously disposed. That is, within edge region A, both the second doped layer 16 and the first doped layer 15 below the second sub-grid 123 extend continuously along the first direction and are arranged alternately along the second direction Y. This simplifies the arrangement of the first doped layer 15 and the second doped layer 16 within edge region A, as well as the arrangement direction of the first grid 11 and the second grid 12, thereby simplifying the cell fabrication process, improving cell fabrication efficiency, reducing cell fabrication costs, and enhancing the market competitiveness of the cells.

[0087] In some embodiments, the first sub-fine grid 121 is a second fine grid 12 within the edge region A that is closest to the first side 13 or the second side 14; the sum of the number of the first fine grid 11 and the second fine grid 12 is N. When N is odd, the breaks 122 in the two edge regions A are arranged opposite each other along the second direction Y. When N is even, the breaks 122 in the two edge regions A are staggered along the second direction Y.

[0088] like Figure 1 As shown, the second fine gate 12 closest to the first side 13 within edge region A is the first sub-fine gate 121. Figure 2 As shown, the second fine gate 12 closest to the second side 14 within the edge region A is the first sub-fine gate 121.

[0089] like Figure 1As shown, the fine grid closest to the first side 13 in the edge region A near the first side 13 is taken as the first sub-fine grid 121.

[0090] When the sum N of the number of first fine grids 11 and second fine grids 12 on the cell body 10 is odd, the fine grid closest to the second side 14 in the edge region A near the second side 14 is also the first sub-fine grid 121. The disconnections 122 on the two first sub-fine grids 121 are arranged opposite each other along the second direction Y to avoid the first sub-fine grid 121 and the first solder strip 80 from becoming conductive, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0091] If the sum N of the number of the first fine grid 11 and the second fine grid 12 on the cell body 10 is an odd number, then the cells no longer need to be distinguished as A and B cells. The cells can be interconnected simply by rotating them 180°. This helps to simplify the manufacturing process of photovoltaic modules, improve the manufacturing efficiency of photovoltaic modules, and enhance the market competitiveness of photovoltaic modules.

[0092] When the sum N of the number of first fine grids 11 and second fine grids 12 on the cell body 10 is even, the fine grid closest to the second side 14 in the edge region A near the second side 14 is the first fine grid 11. The break 122 on the first sub-fine grid 121 needs to be offset from the break on the first fine grid 11 along the second direction Y. The setting of the break 122 on the first sub-fine grid 121 can prevent the first sub-fine grid 121 and the first solder ribbon 80 from conducting, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module. The setting of the break on the first fine grid 11 can prevent the first fine grid 11 and the second solder ribbon from conducting, which would cause a partial short circuit in the photovoltaic module and affect the photoelectric conversion efficiency of the photovoltaic module.

[0093] In some embodiments, the first end line 70 includes one sub-end line, two sub-end lines, or three sub-end lines.

[0094] like Figure 1 As shown, the first terminal line 70 includes only one sub-terminal line, which is disposed on the side of the first pad 20 near the first side 13 or the second side 14. One end of the sub-terminal line is electrically connected to the first pad 20 and extends along the second direction Y to the first side 13 or the second side 14. This sub-terminal line is used to collect the charge carriers gathered by the first fine gate 11 and to transfer the collected charge carriers to the first solder strip 80 through the first pad 20.

[0095] The first terminal line 70 in this embodiment may include two sub-terminal lines. Both sub-terminal lines are disposed on the side of the first pad 20 near the first side 13 or the second side 14. One end of the two sub-terminal lines is electrically connected to the first pad 20, and the other end is far away from each other and extends to the first side 13 or the second side 14, so as to collect the carriers collected by the first fine gate 11 through the two sub-terminal lines and transfer the collected carriers to the first solder strip 80 through the first pad 20.

[0096] like Figure 2 As shown, the first terminal line 70 may also include three sub-terminal lines. All three sub-terminal lines are disposed on the side of the first pad 20 near the first side 13 or the second side 14. One end of each of the three sub-terminal lines is electrically connected to the first pad 20, and the other ends are far apart from each other and extend to the first side 13 or the second side 14, so as to collect the carriers collected by the first fine gate 11 through the three sub-terminal lines and transfer the collected carriers to the first solder strip 80 through the first pad 20.

[0097] It should be noted that the above are merely individual examples of the specific structure of the first end line 70 and are not intended to limit this application. In practical applications, those skilled in the art can also customize the specific structure of the first end line 70 as needed.

[0098] In some embodiments, the height of the first sub-gate 121 is greater than the height of the second sub-gate 123.

[0099] Because the first grid 11 and the second grid 12 are arranged very closely on the back side of the solar cell 10, the first sub-grid 121 is very close to the first side 13 or the second side 14 of the solar cell 10. During the process of forming the first grid 11 and the second grid 12 on the back side of the solar cell 10 by screen printing, the edges of the screen are easily damaged. Therefore, the edges of the screen can be thickened, resulting in the thickness of the first sub-grid 121 being greater than the thickness of the second sub-grid 123, to reduce the screen damage rate. However, because the first sub-grid 121 is thicker than the other grids, it is also more likely to pierce the insulating block, leading to a localized short circuit in the photovoltaic module.

[0100] This application also discloses a photovoltaic module, which includes at least two back-contact solar cells as described in the above embodiments, with the at least two solar cells arranged sequentially along the second direction Y; a first solder strip 80, which extends along the second direction Y and connects the edge regions A of two adjacent solar cells that are close to each other, and the first solder strip 80 passes through the break 122 of the first sub-grid 121.

[0101] This application also discloses a photovoltaic module, which is a back-contact photovoltaic module. Back-contact photovoltaic modules have the characteristics of high photoelectric conversion efficiency and excellent appearance.

[0102] The photovoltaic module disclosed in this application includes at least two of the solar cells described in the above embodiments, such as... Figure 4 As shown, at least two solar cells are arranged sequentially along the second direction Y, and a first solder strip 80 extends along the second direction Y and is disposed on the first surface of the solar cells. The first solder strip 80 connects the adjacent edge regions A of two solar cells that are close to each other, so as to connect the two adjacent solar cells together in series to form a solar cell string.

[0103] Specifically, the first solder ribbon 80 passes through the break 122 of the first sub-grid 121 to prevent the first solder ribbon 80 and the first sub-grid 121 from becoming conductive, thus avoiding a partial short circuit in the photovoltaic module. Furthermore, this design also prevents the first sub-grid 121 from piercing the insulating block, thus preventing the first sub-grid 121 and the first solder ribbon 80 from becoming conductive and causing a partial short circuit in the photovoltaic module, which would affect the photoelectric conversion efficiency of the photovoltaic module.

[0104] It is understandable that in the first sub-gate 121, the break point 122 is only required where the first solder strip 80 passes through. This reduces the number of break points 122 and lowers the carrier collection loss caused by the break points in the first sub-gate 121.

[0105] In some embodiments, the width of the break 122 along the first direction X is L1, and the width of the first solder strip 80 along the first direction X is L3, satisfying 1.5*L3≤L1≤10*L3.

[0106] In this embodiment of the application, the width L1 of the break 122 along the first direction X is set to be greater than or equal to 1.5 times the width L3 of the first solder strip 80 along the first direction X, and less than or equal to 10 times the width L3 of the first solder strip 80 along the first direction X.

[0107] For example, L1 = 1.5 * L3; or, L1 = 1.8 * L3; or, L1 = 2 * L3; or, L1 = 3 * L3; or, L1 = 4 * L3; or, L1 = 5 * L3; or, L1 = 8 * L3; or, L1 = 10 * L3.

[0108] If the width L1 of the break point 122 along the first direction X is less than 1.5 times the width L3 of the first solder strip 80 along the first direction X, the first solder strip 80 is likely to be connected to the first sub-grid 121, resulting in a partial short circuit in the photovoltaic module and affecting the photoelectric conversion efficiency of the photovoltaic module.

[0109] If the width L1 of the break 122 along the first direction X is greater than 5 times the width L3 of the first solder strip 80 along the first direction X, the width L1 of the break 122 along the first direction X is too wide, which affects the extension length of the first sub-gate 121 along the first direction X, and thus affects the carrier collection efficiency of the first sub-gate 121.

[0110] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0111] Although alternative embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the alternative embodiments as well as all changes and modifications falling within the scope of the present invention.

[0112] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity from another, and do not necessarily require or imply any such actual relationship or order between these entities. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or terminal device that includes that element.

[0113] The technical solution provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the principle and implementation of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A back-contact battery cell, characterized in that, include: The battery cell body (10) has a first surface and a second surface disposed opposite to each other. The first surface is provided with a first grid (11) and a second grid (12) that extend along a first direction (X) and are alternately spaced along a second direction (Y). Along the second direction (Y), the battery cell body (10) has a first side (13) and a second side (14) disposed opposite to each other. The area of ​​the battery cell body (10) close to the first side (13) or the second side (14) is an edge area (A), and the area of ​​the battery cell body (10) relatively far away from the first side (13) or the second side (14) is a middle area (B). The second direction (Y) intersects with the first direction (X). A first pad (20) is provided in the edge region (A), the first pad (20) is connected to at least one first fine gate (11), at least one second fine gate (12) in the edge region (A) closest to the first side (13) or the second side (14) is a first sub-fine gate (121), the first sub-fine gate (121) is disconnected at the extension of the first pad (20) along the second direction (Y); The battery cell body (10) includes a doped layer, which includes a second doped layer (16). The second doped layer (16) is disposed corresponding to the second fine grid (12). The second doped layer (16) below the break (122) of the first sub-fine grid (121) is continuous.

2. The back-contact battery cell according to claim 1, characterized in that, Within the intermediate region (B), the first fine grid (11) penetrates the battery cell body (10) along the first direction (X); And / or, within the intermediate region (B), the second fine grid (12) penetrates the cell body (10) along the first direction (X).

3. The back-contact battery cell according to claim 2, characterized in that, The intermediate region (B) is provided with a first main gate (30) extending along the second direction (Y); The first main grid (30) is electrically connected to the first fine grid (11), and a first insulating block (40) is provided between the first main grid (30) and the second fine grid (12).

4. The back-contact battery cell according to claim 1, characterized in that, The width of the first sub-fine gate (121) break (122) along the first direction (X) is L1, which satisfies 1mm≤L1≤5mm.

5. The back-contact battery cell according to claim 4, characterized in that, A second insulating block (50) is provided at the break (122) of the first sub-fine grid (121), and the length of the second insulating block (50) along the first direction (X) is L2, satisfying L2≥L1; And / or, the second insulating block (50) covers the end of the first sub-grid (121) near the break (122).

6. The back-contact battery cell according to claim 1, characterized in that, The edge region (A) is further provided with a first end line (70), the first end line (70) is connected to the side of the first pad (20) near the first side (13) or the second side (14), and the first end line (70) is connected to the first fine gate (11). The second fine grid (12) in the edge region (A) that is relatively far from the first side (13) or the second side (14) is the second sub-fine grid (123), which is broken at the first end line (70); or, the second sub-fine grid (123) extends along the first direction (X) and a third insulating block (60) is provided at the intersection with the first end line (70).

7. The back-contact battery cell according to claim 6, characterized in that, The doped layer further includes a first doped layer (15), which is disposed corresponding to the first fine gate (11). The second doped layer (16) below the second sub-gate (123) is discontinuously arranged, and the second doped layer (16) below the second sub-gate (123) and the first doped layer (15) have an interdigitated structure; Alternatively, the second doped layer (16) below the second sub-gate (123) is continuously disposed, and the second doped layer (16) below the second sub-gate (123) and the first doped layer (15) both extend along the first direction (X) and are arranged alternately along the second direction (Y).

8. The back-contact battery cell according to claim 1, characterized in that, The first sub-gate (121) is a second gate (12) within the edge region (A) that is closest to the first side (13) or the second side (14); The sum of the number of the first fine gate (11) and the second fine gate (12) is N. When N is odd, the breaks (122) in the two edge regions (A) are arranged opposite each other along the second direction (Y). When N is even, the breaks (122) in the two edge regions (A) are staggered along the second direction (Y).

9. The back-contact battery cell according to claim 6, characterized in that, The first end line (70) includes one sub-end line, two sub-end lines, or three sub-end lines.

10. A photovoltaic module, characterized in that, It includes at least two back-contact solar cells as described in any one of claims 1-9, wherein the at least two solar cells are arranged sequentially along the second direction (Y); The first solder strip (80) extends along the second direction (Y) and connects the edge regions (A) of two adjacent cells that are close to each other. The first solder strip (80) passes through the break (122) of the first sub-grid (121).

11. The photovoltaic module according to claim 10, characterized in that, The width of the break (122) along the first direction (X) is L1, and the width of the first solder strip (80) along the first direction (X) is L3, satisfying 1.5*L3≤L1≤10*L3.

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