Solar cell and solar module

Abstract

The application relates to a solar cell and a solar module, comprising a cell substrate, a first main grid, a first auxiliary grid comprising a plurality of parallel and spaced fine grids, at least one of the plurality of fine grids being located in a passivation region, and a first connecting structure respectively arranged at the length direction of the fine main grid, the first connecting structure comprising a bifurcated line and an auxiliary line, one end of the bifurcated line being electrically connected with the first main grid, the other end extending away from the fine main grid and being electrically connected with the fine grid located in the passivation region, and the auxiliary line being located in the passivation region and being electrically connected with the bifurcated line on the same fine grid. The application not only enables the fine grid located in the passivation region to continue collecting photo-generated carriers, thereby eliminating the shadow generated by the broken edge fine grid inside the traditional design of a fishing rod and remedying the power loss at the position, but also enables the absorbed and collected current at the passivation region to be led out to the first main grid through the auxiliary line and the bifurcated line, which is also beneficial to improving the collection efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic solar energy technology, and in particular to solar cells and solar modules. Background Technology

[0002] With the photovoltaic industry's ever-increasing demands for cell conversion efficiency and solar module power, TOPCon (Tunnel Oxide Passivating Contacts) cells have become one of the mainstream technologies due to their excellent passivation performance and higher efficiency potential. In the cell manufacturing process, the printing design of the metallized electrodes is crucial, directly affecting the cell's current collection efficiency, series resistance, and the reliability of the solar module.

[0003] In related technologies, to avoid lamination breakage, the printing design needs to disconnect several fine grids at the edge of the battery, resulting in severe shading and power loss in the disconnected area. Utility Model Content

[0004] Therefore, it is necessary to provide a solar cell and solar module to address the problem that in traditional printing designs, in order to avoid lamination breakage, several fine grids at the edge of the cell need to be disconnected, resulting in severe shading and power loss in the disconnected area.

[0005] In a first aspect, embodiments of this application provide a solar cell, the solar cell comprising:

[0006] A battery substrate includes a first surface and a second surface disposed opposite to each other, wherein the edge of the first surface has a passivated region.

[0007] A first main gate is disposed on the first surface. The first main gate includes a fine main gate and pads spaced apart on the fine main gate. The pads are provided at both ends of the length direction of the fine main gate.

[0008] A first sub-gate is disposed on the first surface. The first sub-gate includes a plurality of parallel and spaced fine gates, and some of the fine gates are connected to the pads and intersect with the fine main gate; at least one of the plurality of fine gates is located in the passivation region.

[0009] A first connection structure is disposed on the first surface and at both ends of the fine main gate along its length. The first connection structure includes a branch line and an auxiliary line. One end of the branch line is electrically connected to the first main gate, and the other end extends in a direction away from the fine main gate and is electrically connected to the fine gate located in the passivation region. The auxiliary line is located in the passivation region and is electrically connected to the branch line on the same fine gate.

[0010] In one embodiment, the first connection structure includes at least one of the auxiliary lines, the auxiliary line being perpendicular to the fine grid;

[0011] The first connection structure includes two branch lines, which are located on opposite sides of the pad along the extension direction of the fine gate.

[0012] And / or, the fine main gate is perpendicular to the fine gate.

[0013] In one embodiment, the first connection structure includes an auxiliary line;

[0014] The passivation region has at least two fine grids, one end of the auxiliary line is electrically connected to one of the fine grids near the edge of the battery substrate, and the other end is electrically connected to one of the fine grids away from the edge of the battery substrate.

[0015] In one embodiment, the auxiliary line, the branch line, and the first main grid are integrally formed by silver paste printing;

[0016] And / or, the line width of the auxiliary line is 0.03mm-0.06mm.

[0017] In one embodiment, the first connection structure includes a plurality of auxiliary lines;

[0018] The passivation region has at least two fine grids, and at least one fine grid near the edge of the battery substrate includes a first sub-grid and a second sub-grid that are spaced apart; one of the plurality of auxiliary lines is electrically connected to the ends of all the first sub-grids, and the other of the plurality of auxiliary lines is electrically connected to the ends of all the second sub-grids.

[0019] In one embodiment, an auxiliary line located between the first sub-gate and the second sub-gate is defined as a sub-auxiliary line, one end of which is electrically connected to a continuous fine grid away from the edge of the battery substrate, and the other end is flush with a fine grid close to the edge of the battery substrate.

[0020] In one embodiment, the spacing between two adjacent auxiliary lines is equal to the spacing between two adjacent fine grids;

[0021] And / or, along the extension direction of the fine gate, the ratio of the sum of the spacing of all the auxiliary lines to the width of the pad is greater than or equal to 1.5;

[0022] And / or, the line width of the auxiliary line is 0.02mm-0.04mm.

[0023] In one embodiment, the auxiliary line and the fine grid are integrally formed by silver paste printing, and the branch line and the first main grid are integrally formed by silver paste printing.

[0024] In one embodiment, the two bifurcation lines are parallel to each other and perpendicular to the fine grid;

[0025] And / or, the ratio of the distance between the two bifurcated lines to the width of the pad along the extension direction of the fine gate is 1.2-1.5;

[0026] And / or, the line width of the bifurcation line is 0.03mm-0.06mm;

[0027] And / or, the end of the branch line away from the auxiliary line is electrically connected to the fine gate connected to the pad, or the end of the branch line away from the auxiliary line is electrically connected to the pad.

[0028] In one embodiment, the auxiliary line, the branch line, and the fine grid are integrally formed by silver paste printing.

[0029] In one embodiment, the bifurcation line includes a first sub-line and a second sub-line connected in sequence along the direction away from the fine main gate. The two first sub-lines are arranged parallel to each other, and the end of the first sub-line away from the second sub-line is electrically connected to the pad.

[0030] The spacing between the two second sub-lines gradually increases in the direction away from the pad, and the ends of the second sub-lines away from the first sub-line are electrically connected to the fine gate located in the passivation region;

[0031] And / or, the line width of the bifurcation line is 0.03mm-0.06mm.

[0032] In one embodiment, the solar cell further includes a second main grid, a second sub-grid, and a second connection structure. The second main grid, the second sub-grid, and the second connection structure are disposed on the second surface, and the second main grid has the same structure as the first main grid, the second sub-grid has the same structure as the first sub-grid, and the second connection structure has the same structure as the first connection structure.

[0033] Secondly, embodiments of this application provide a solar module including a plurality of solar cells as described in the first aspect, wherein the plurality of solar cells are connected to each other by solder strips.

[0034] The aforementioned solar cells and solar modules, by setting at least one fine grid in the passivation region located on the first surface of the cell substrate, connecting the at least one fine grid in the passivation region with auxiliary lines, and electrically connecting the fine grid in the passivation region to the first main grid with branch lines, not only allow the fine grid in the passivation region to continue collecting photogenerated carriers, thereby eliminating the shadows caused by disconnecting the edge fine grid inside the harpoon in conventional designs and compensating for power loss at that point, but also improve the collection efficiency by allowing the current absorbed and collected in the passivation region to be led to the first main grid via auxiliary lines and branch lines. Furthermore, by optimizing the first connection structure into branch lines and auxiliary lines, this embodiment achieves a finer pattern and lower slurry stacking, thereby reducing the stacking of metal under the solder ribbon. This reduces the risk of stress concentration caused by excessive stacking height, which can lead to microcracks or cell breakage, and improves the yield and reliability of solar cell production. Attached Figure Description

[0035] Figure 1a This is a schematic diagram of the structure of a solar cell according to some embodiments of this application.

[0036] Figure 1b This is a partial structural diagram of a solar cell using grid paste printing according to some embodiments of this application.

[0037] Figure 1c This is a partial structural schematic diagram of a solar cell using sub-grid paste printing according to some embodiments of this application.

[0038] Figure 2a This is a schematic diagram of another solar cell structure provided according to some embodiments of this application.

[0039] Figure 2b This is a schematic diagram of the structure of a portion of another solar cell using grid paste printing according to some embodiments of this application.

[0040] Figure 2c This is a schematic diagram of the structure of a portion of a solar cell using sub-grid paste printing according to some embodiments of this application.

[0041] Figure 3a This is a schematic diagram of the structure of another solar cell provided according to some embodiments of this application.

[0042] Figure 3b This is a schematic diagram of the structure of a portion of a solar cell using grid paste printing according to some embodiments of this application.

[0043] Figure 3cThis is a schematic diagram of the structure of a portion of a solar cell using sub-grid paste printing according to some embodiments of this application.

[0044] Icon labels:

[0045] 100. Battery substrate; 101. Passivation region;

[0046] 200, First main gate; 210, Fine main gate; 220, Pad;

[0047] 300, First sub-grid; 310, Fine grid;

[0048] 400, First connection structure; 410, Branch line; 411, First sub-line; 412, Second sub-line; 420, Auxiliary line. Detailed Implementation

[0049] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0050] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0051] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0053] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0054] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0055] As mentioned in the background section, the welding screen pattern of conventional TOPCon cells typically features a fork structure at the beginning and end of the cell. This fork pattern is usually printed using two types of metal paste: the fine grid (or sub-grid) is printed using a burn-through paste to burn through the silicon nitride insulating layer on the cell surface, achieving ohmic contact with the silicon substrate and collecting photogenerated carriers; while the main grid, fork, PAD points (or pads), and main grid connection lines are printed using a non-burn-through paste to collect the fine grid current and weld it to the external solder strip.

[0056] The design patterns in related technologies have at least the following problems. To avoid the risk of cell breakage during lamination, traditional designs typically involve disconnecting several fine grids at the edge of the cell within the harpoon structure. The risk of breakage stems primarily from two factors: first, the sub-grid line height is relatively high; second, solder layer accumulation easily occurs after the solder ribbon is welded to the edge grid lines. These two factors lead to localized stress concentration at the cell edge during lamination. While disconnecting the fine grids effectively reduces the breakage rate, it creates areas at the cell edge where current cannot be effectively collected. These areas are prone to severe localized shading, resulting in significant power loss. Taking a 210R 16BB two-cell cell as an example, the power loss due to this shading is approximately 2W; if more segments are used, this power loss will increase exponentially.

[0057] Furthermore, existing harpoon patterns often employ an inclined line design. When using screen printing, the inclined harpoon pattern is prone to grid breakage due to the obstruction of the mesh knots. The current of the fine grid outside the PAD point relies entirely on the harpoon for transmission. Once the harpoon breaks, this part of the current cannot be effectively discharged, causing the battery to appear as a dark shadow in EL (electroluminescence) testing, resulting in current loss and reduced yield.

[0058] It's important to understand that, to improve battery efficiency, current TOPCon cells undergo a passivation treatment by depositing alumina on the cut edges after dicing to repair cutting damage and suppress edge recombination. The approximately 30nm thick alumina layer deposited in this process acts as an insulator, covering the metal grid lines in the edge area. This causes the metal grid lines within a 1-3mm range of the cell edge to lose their wetting properties with the solder ribbon, making reliable soldering virtually impossible. Given this situation, there is an urgent need in the field for a new photovoltaic cell metallization patterning design scheme that can effectively solve at least one of the problems existing in related technologies, such as the risk of lamination breakage, the risk of harpoon grid breakage, and power loss due to edge shading, while maintaining compatibility with the cell edge passivation process.

[0059] To address the aforementioned problems, this application provides a solar cell and solar module. By setting at least one fine grid in the passivation region of the first surface of the cell substrate, connecting the at least one fine grid in the passivation region with auxiliary lines, and electrically connecting the fine grid in the passivation region to the first main grid with branch lines, this arrangement not only allows the fine grid in the passivation region to continue collecting photogenerated carriers, thereby eliminating the shadows caused by disconnecting the edge fine grid inside the harpoon in conventional designs and compensating for power loss at that point, but also improves collection efficiency by allowing the current absorbed and collected in the passivation region to be led to the first main grid via auxiliary lines and branch lines. Furthermore, by optimizing the first connection structure into branch lines and auxiliary lines, this embodiment achieves a finer pattern and lower slurry stacking, thereby reducing the stacking of metal under the solder strip. This reduces the risk of stress concentration caused by excessive stacking height, which can lead to microcracks or cell breakage, thus improving the yield and reliability of solar cell production.

[0060] See Figure 1a , Figure 1a This is a schematic diagram of the structure of a solar cell according to some embodiments of this application. One embodiment of the solar cell provided in this application may include a cell substrate 100, a first main grid 200, a first sub-grid 300, and a first connection structure 400.

[0061] The battery substrate 100 includes a first surface and a second surface disposed opposite to each other, and the edge of the first surface has a passivation region 101; a first main gate 200 is disposed on the first surface, the first main gate 200 includes a fine main gate 210 and pads 220 spaced apart on the fine main gate 210, and pads 220 are provided at both ends of the fine main gate 210 in the length direction; a first sub-gate 300 is disposed on the first surface, the first sub-gate 300 includes a plurality of parallel and spaced fine gates 310, and some of the fine gates 310 are connected to the pads 220 and intersect with the fine main gate 210; multiple At least one of the fine gates 310 is located in the passivation region 101; the first connection structure 400 is disposed on the first surface and at both ends of the fine main gate 210 along its length. The first connection structure 400 includes a branch line 410 and an auxiliary line 420. One end of the branch line 410 is electrically connected to the first main gate 200, and the other end extends in a direction away from the fine main gate 210 and is electrically connected to the fine gate 310 located in the passivation region 101. The auxiliary line 420 is located in the passivation region 101 and is electrically connected to the branch line 410 on the same fine gate 310.

[0062] It is understood that the battery substrate 100 provided in this embodiment can be a crystalline silicon wafer, such as N-type monocrystalline silicon. The battery substrate 100 has a first surface and a second surface opposite to each other. If the first surface is the light-receiving surface, then the second surface is the back surface. The battery substrate 100 can be used to absorb light energy and generate photogenerated carriers, and to transmit current through the sub-gate and main gate described below. In this example, both sides of the battery substrate 100 are provided with a main gate, a sub-gate, and a connection structure. For ease of understanding, this example temporarily describes the arrangement and connection method of the first main gate 200, the first sub-gate 300, and the first connection structure 400 provided on the first surface. The specific structure on the second surface can be understood with reference to the first surface.

[0063] After the complete solar cell is diced, to repair cutting damage, suppress edge carrier recombination, and improve the open-circuit voltage, atomic layer deposition (ALD) or plasma-enhanced chemical vapor deposition (PECVD) processes are typically used to deposit an aluminum oxide film with a thickness of approximately 30 nm on the edges and adjacent surfaces (first and second surfaces) of the diced solar cell substrate 100. It is important to understand that the insulating properties of this aluminum oxide (passivation effect) also cause the metal grid lines covered by it to lose their solderability. However, since the deposited aluminum oxide film is transparent, it does not affect the absorption of light energy and the generation of photogenerated carriers in the passivation region 101.

[0064] In this example, the first main grid 200 includes a fine main grid 210 and pads 220. The fine main grid 210 is one or more relatively wide conductive grid lines extending along the length of the cell. The main function of the fine main grid 210 is to collect current. In this example, the fine main grid 210 is formed by screen printing and sintering using a non-burn-through metal paste. In other words, the paste of the fine main grid 210 does not need to burn through the silicon nitride antireflective coating on the cell surface; its contact with the silicon substrate mainly relies on its connection with the sub-grid. The pads 220, also known as PADs, are distributed on the fine main grid 210 at a certain spacing. The pads 220 serve as contact points for soldering, and their surface area is typically larger than the width of the fine main grid 210 to provide sufficient soldering area. Similarly, the pads 220 are also printed using a non-burn-through metal paste and can be integrally formed with or electrically connected to the fine main grid 210. For example, both ends of the fine main grid 210 are provided with solder pads 220 for connecting with the solder strip during battery stringing.

[0065] Additionally, the first sub-gate 300 includes multiple fine gates 310, which are parallel to each other and spaced apart, extending in a direction approximately perpendicular to the fine main gate 210. The ends or middle portions of some fine gates 310 are connected to pads 220, and all fine gates 310 intersect the fine main gate 210 to transfer the collected current to the main gate and out through the solder ribbon. In this example, the fine gates 310 are formed by screen printing and sintering using a burn-through type metal paste; in other words, the paste used for the fine gates 310 can burn through the silicon nitride layer on the surface of the battery, forming a good ohmic contact with the underlying silicon emitter, thereby efficiently collecting photogenerated carriers.

[0066] In this example, at least one of the multiple fine gates 310 is disposed in the passivation region 101. It is understood that the passivation region 101 is located at the edge of the first surface, and the extension direction of the fine gates 310 is consistent with the extension direction of the edge. Therefore, the number of fine gates 310 disposed in the passivation region 101 is determined according to the width of the passivation region 101. For example, the width of the passivation region 101 is 1mm-3mm, and the outermost fine gate 310 is 0.4mm-1mm away from the edge of the battery substrate 100. Based on the actual spacing between two adjacent fine gates 310, it can be determined that the passivation region 101 is provided with approximately 1-4 fine gates 310. It should be noted that although the fine gates 310 located in the passivation region 101 cannot be soldered due to the passivation layer, their burn-through paste can still collect charge carriers from the edge region of the first surface.

[0067] In this example, the first connection structure 400 can be understood as a structure connecting the fine grid 310 and the fine main grid 210 / pad 220 located in the passivation region 101. Specifically, the first connection structure 400 is disposed on the first surface and at both ends of the fine main grid 210 along its length, corresponding to the pad 220 positions at the beginning and end of the solar cell. The first connection structure 400 acts as a bridge for current flow, diverting the current collected from the fine grid 310 in the passivation region 101 to the first main grid 200, thereby preventing the loss of this current due to edge welding failure.

[0068] To describe the structure of the first connection structure 400 more specifically, it is decomposed into a branch line 410 and an auxiliary line 420. One end of the branch line 410 is electrically connected to the first main gate 200, for example, it can be directly connected to the pad 220 or the fine main gate 210, while the other end extends away from the fine main gate 210, that is, toward the edge of the cell. Importantly, the end of the branch line 410 is electrically connected to the fine gate 310 located in the passivation region 101. In other words, the branch line 410 provides a low-resistance path for the current collected by the edge fine gate 310 to flow directly into the main gate.

[0069] The auxiliary line 420 is located within the passivation region 101, and its branch line 410 is electrically connected to the same fine gate 310. Specifically, both the auxiliary line 420 and the branch line 410 intersect with the same fine gate 310 located in the passivation region 101. However, the auxiliary line 420 and the branch line 410 are not necessarily connected to the same point on the fine gate 310. It should be understood that the design of the auxiliary line 420 is more advantageous when the passivation region 101 has two or more fine gates 310. For example, when the passivation region 101 has two parallel fine gates 310, the two fine gates 310 can be connected by the auxiliary line 420 to collect the current of the outermost fine gate 310 and transmit it to the fine gate 310 connected to it, so that the current of all the fine gates 310 in the passivation region 101 can be transmitted to the first main gate 200 through the branch line 410.

[0070] In this embodiment, the branch line 410 and the auxiliary line 420 can be formed by printing with a non-burn-through main gate paste, or by printing with a burn-through secondary gate paste, or a combination of both. For example, the branch line 410 uses the main gate paste and the auxiliary line 420 uses the secondary gate paste; or, for another example, the branch line 410 uses the secondary gate paste and the auxiliary line 420 uses the main gate paste. Using the secondary gate paste allows for the utilization of its lower resistivity to reduce current transmission losses.

[0071] In this embodiment, the branching line 410 can be a straight line, a curve, or a multi-segment line, while the auxiliary line 420 can be a short line perpendicular to the fine grid 310, without limitation. Furthermore, the fine grid 310 located in the passivation region 101 can be fully formed or disconnected, or the fine grid 310 near the edge of the battery substrate 100 can be disconnected, while one fine grid 310 connected to the branching line 410 can be fully formed. However, it is necessary to ensure that the gap between the disconnected fine grids 310 is less than 0.2 mm. For specific details, please refer to the following examples.

[0072] It should be noted that this embodiment takes advantage of the fact that the edge passivation layer causes welding failure, and eliminates the accumulation of metal in the ineffective welding area. Instead, the design focus is shifted from welding reinforcement to current collection and conduction. Without reducing the electrical performance gain brought by passivation, the problem of power loss is also solved.

[0073] In summary, the solar cell provided in this application provides at least one fine grid 310 located in the passivation region 101 on the first surface of the cell substrate 100, and connects the at least one fine grid 310 located in the passivation region 101 with an auxiliary line 420, and electrically connects the fine grid 310 located in the passivation region 101 with the first main grid 200 with a branch line 410. This arrangement not only allows the fine grid 310 located in the passivation region 101 to continue collecting photogenerated carriers, thereby eliminating the shadows caused by disconnecting the edge fine grid 310 inside the harpoon in the conventional design and compensating for the power loss there, but also helps to improve the collection efficiency by allowing the current absorbed and collected in the passivation region 101 to be led to the first main grid 200 via the auxiliary line 420 and the branch line 410. Moreover, this embodiment optimizes the first connection structure 400 into a branch line 410 and an auxiliary line 420, making the pattern more refined and the stacked paste lower, thereby reducing the stacking of metal under the solder strip. This reduces the risk of stress concentration caused by excessive stacking height, which can lead to microcracks or cell breakage, and improves the yield and reliability of solar cell production.

[0074] Below, we will combine the appendix Figure 1a - Appendix Figure 3c The specific structure of the solar cell provided in the embodiments of this application will be described in detail.

[0075] like Figures 1a-1c As shown, Figure 1b This is a partial structural diagram of a solar cell using grid paste printing according to some embodiments of this application. Figure 1c This is a partial structural schematic diagram of a solar cell using sub-grid paste printing according to some embodiments of this application. In some embodiments, the first connection structure 400 includes at least one auxiliary line 420, which is perpendicular to the fine grid 310; the first connection structure 400 includes two branch lines 410, which are located on opposite sides of the pad 220 along the extension direction of the fine grid 310.

[0076] It is understood that the auxiliary line 420 can connect two adjacent fine grids 310, or the auxiliary line 420 can connect only the fine grids 310 that are connected to the branch line 410. In this case, the auxiliary line 420 can be made of fine grid 310 burn-through paste. The auxiliary line 420 can be regarded as the fine grid 310 extracting charge carriers from the battery substrate 100 and transmitting them to the fine grid 310 connected to the branch line 410, and then transmitting them to the main grid through the branch line 410.

[0077] The branch lines 410 are set as two, and are symmetrically distributed about the central axis of the extension direction of the fine gate 310 about the pad 220, that is, they are located on the left and right sides of the pad 220 respectively. This design can ensure that the current flows from the edge area to the pad 220 with the shortest path and impedance balance. The combination of auxiliary line 420 and branch line 410 is beneficial to further reduce the series resistance and transmission loss on this path.

[0078] It should be noted that the two branch lines 410 in this embodiment can be arranged parallel to each other or have a certain expansion angle. If they are arranged parallel, the reliance on screen knots can be reduced, and high-quality printing can be achieved even on screens with lower mesh counts, thereby greatly reducing the risk of printing grid breakage caused by screen knot obstruction.

[0079] In one example, the fine main gate 210 is perpendicular to the fine gate 310. This design facilitates the uniform collection of the sub-gate current by the main gate.

[0080] In some embodiments, the first connection structure 400 includes an auxiliary line 420; the passivation region 101 has at least two fine gates 310, one end of the auxiliary line 420 is electrically connected to a fine gate 310 near the edge of the battery substrate 100, and the other end is electrically connected to a fine gate 310 away from the edge of the battery substrate 100.

[0081] Specifically, when there are multiple fine gates 310 in the passivation region 101, only one auxiliary line 420 can be used to connect the multiple fine gates 310 located in the passivation region 101 respectively, so as to collect the current of the multiple fine gates 310 and conduct it to the innermost fine gate 310, and then the current is finally fed into the main gate through the branch line 410 connected to the inner fine gate 310.

[0082] This embodiment achieves the convergence of current from multiple edge grids 310 with minimal metal paste usage, minimizing the light-shielding area of ​​the first connection structure 400 and paste cost. Simultaneously, the simplified pattern also contributes to improved printing yield. For example... Figure 1b and Figure 1c As shown, in some embodiments, the auxiliary line 420, the branch line 410, and the first main grid 200 are integrally formed by silver paste printing. In this embodiment, the auxiliary line 420, the branch line 410, and the first main grid 200 all use the same silver paste and are simultaneously printed in the same screen printing process, ultimately forming a continuous, integrated metal electrode structure through co-firing. This integrated printing process simplifies the manufacturing process, reduces production steps, and lowers manufacturing costs. Simultaneously, the integrated structure avoids contact resistance and adhesion problems that may arise from different paste layers or multiple printing alignments, improving the mechanical stability and electrical reliability of the electrode.

[0083] In one example, the line width of the auxiliary line 420 is 0.03mm-0.06mm. Exemplarily, the line width of the auxiliary line 420 can be 0.03mm, 0.04mm, 0.05mm, or 0.06mm. This is to minimize light-shielding loss while ensuring sufficient current carrying capacity and printing yield.

[0084] Besides the design methods mentioned above, it can also be, for example... Figures 2a-2c As shown, Figure 2a This is a schematic diagram of another solar cell structure provided according to some embodiments of this application. Figure 2b This is a schematic diagram of the structure of a portion of another solar cell using grid paste printing according to some embodiments of this application. Figure 2c This is a schematic diagram of the structure of a portion of a solar cell using sub-grid paste printing according to some embodiments of this application. In some embodiments, the first connection structure 400 includes a plurality of auxiliary lines 420; the passivation region 101 has at least two fine grids 310, and at least one fine grid 310 near the edge of the cell substrate 100 includes a first sub-grid and a second sub-grid spaced apart; one of the plurality of auxiliary lines 420 is electrically connected to the ends of all the first sub-grids, and the other of the plurality of auxiliary lines 420 is electrically connected to the ends of all the second sub-grids.

[0085] It is understood that in this embodiment, at least one fine grid 310 near the edge of the battery substrate 100 is disconnected. The disconnection point can be the position corresponding to the extended fine main grid 210. For example, the passivation region 101 has three fine grids 310, and two fine grids 310 near the edge are disconnected. That is, it includes two parallel first sub-grids and two parallel sub-grids with a blank area in between. This blank area can be left empty. In this case, the distance between the disconnected first sub-grid and the second sub-grid needs to be equal to or approximately equal to the distance between adjacent fine grids 310. Of course, an auxiliary line 420 can also be set in this blank area, and one end of the auxiliary line 420 is electrically connected to a complete fine grid 310 on the inner side.

[0086] In this embodiment, the two disconnected first sub-grids and two second sub-grids are each connected by an auxiliary line 420, and the end of the auxiliary line 420 is connected to a complete fine grid 310 on the inner side to form two independent collection busbars. The spacing between two adjacent auxiliary lines 420 is equal to the spacing between adjacent fine grids 310. In one example, the auxiliary line 420 and the fine grid 310 are integrally formed by silver paste printing. Specifically, in this embodiment, the auxiliary line 420 and the fine grid 310 are completed in one printing step using a secondary grid burn-through silver paste. In this example, the auxiliary line 420 and the fine grid 310 use a low-resistivity, burn-through paste to ensure optimal current collection and transmission.

[0087] In some embodiments, an auxiliary line 420 located between the first sub-gate and the second sub-gate is defined as a sub-auxiliary line. One end of the sub-auxiliary line is electrically connected to a continuous fine grid 310 away from the edge of the battery substrate 100, and the other end is flush with a fine grid 310 near the edge of the battery substrate 100.

[0088] Specifically, the sub-auxiliary line is located in the blank area of ​​the aforementioned broken grid 310. This sub-auxiliary line does not directly connect to the outermost broken grid, but rather connects to a complete grid 310 on its inner side, while its outer side remains flush with the end of the broken grid and does not connect to any grid 310. In one example, the auxiliary line 420 and the grid 310 are integrally formed by silver paste printing.

[0089] More specifically, in this embodiment, the auxiliary line 420 is used as a fine gate 310, which can not only collect charge carriers, but also greatly reduce the contact resistance between the auxiliary line 420 and the fine gate 310, so as to efficiently transfer current to the inner fine gate 310 with minimal loss.

[0090] In some embodiments, the spacing between two adjacent auxiliary lines 420 is equal to the spacing between two adjacent fine gates 310. Specifically, the spacing between each auxiliary line 420 is consistent with the spacing between the fine gates 310, which makes the graphic design more regular.

[0091] In one example, along the extension direction of the fine gate 310, the ratio of the sum of the spacing of all auxiliary lines 420 to the width of the pad 220 is greater than or equal to 1.5. Specifically, this arrangement ensures that the collection area is large enough.

[0092] In one example, the linewidth of the auxiliary line 420 is 0.02mm-0.04mm. Specifically, the linewidth of the auxiliary line 420 can be consistent with the linewidth of the fine grid 310. For example, the linewidth of the auxiliary line 420 is 0.02mm, 0.03mm, 0.04mm, etc. By using a finer linewidth and supplementing it with a low-resistivity paste for the sub-grid, light-shielding loss can be reduced and the consumption of precious metals can be reduced.

[0093] In some embodiments, the auxiliary line 420 and the fine grid 310 are integrally formed by silver paste printing, and the branch line 410 and the first main grid 200 are integrally formed by silver paste printing.

[0094] For example, the auxiliary line 420 and the fine grid 310 are formed in one printing using the sub-grid paste, while the branch line 410 and the first main grid 200 are formed in another printing using the main grid non-burn-through paste. By using low-resistance, burn-through paste for the auxiliary line 420 and the fine grid 310, optimal current collection and transmission are ensured; and by using high aspect ratio, weldable non-burn-through paste for the branch line 410 and the main grid, current collection and mechanical strength are ensured.

[0095] In some embodiments, the two branch lines 410 are parallel to each other and perpendicular to the fine grid 310. Exemplarily, the branch lines 410, which are parallel to and perpendicular to the fine grid 310, can reduce the reliance on screen knots and enable high-quality printing even on screens with lower mesh counts, thereby greatly reducing the risk of screen breakage caused by knot obstruction.

[0096] In one example, the ratio of the distance between the two branch lines 410 to the width of the pad 220 along the extension direction of the fine gate 310 is 1.2-1.5. Exemplarily, this ratio can be 1.2, 1.3, 1.4, 1.5, etc., to achieve a balance between current transfer efficiency and paste saving.

[0097] In one example, the line width of the fork line 410 is 0.03mm-0.06mm; for example, the line width can be 0.03mm, 0.04mm, 0.05mm, etc.

[0098] In one example, the end of the branch line 410 facing away from the auxiliary line 420 is electrically connected to the fine gate 310 connected to the pad 220, or the end of the branch line 410 facing away from the auxiliary line 420 is electrically connected to the pad 220. Specifically, different connection methods at the ends of the branch line 410 can improve the mechanical strength of the connection to the pad 220, or save main gate paste when connected to the fine gate 310.

[0099] In addition to the design methods described in the above embodiments, other options include, for example... Figures 3a-3c As shown, Figure 3a This is a schematic diagram of the structure of another solar cell provided according to some embodiments of this application. Figure 3b This is a schematic diagram of the structure of a portion of a solar cell using grid paste printing according to some embodiments of this application. Figure 3c This is a schematic diagram of the structure of a portion of a solar cell using sub-grid paste printing according to some embodiments of this application. In some embodiments, the auxiliary line 420, the branch line 410, and the fine grid 310 are integrally formed by silver paste printing.

[0100] It is understood that in this embodiment, the auxiliary line 420, the branch line 410, and all the fine grids 310 use the same paste (e.g., sub-grid burn-through silver paste) and are formed in the same printing process. This simplifies the process and maximizes the use of low-resistivity paste. The entire current collection and edge busbar are composed of low-resistivity burn-through paste, significantly reducing the total resistance.

[0101] like Figure 3a and Figure 3bAs shown, in some embodiments, the branch line 410 includes a first sub-line 411 and a second sub-line 412 connected in sequence along the direction away from the fine main gate 210. The two first sub-lines 411 are arranged parallel to each other, and the end of the first sub-line 411 away from the second sub-line 412 is electrically connected to the pad 220. The spacing between the two second sub-lines 412 gradually increases along the direction away from the pad 220, and the end of the second sub-line 412 away from the first sub-line 411 is electrically connected to the fine gate 310 located in the passivation region.

[0102] Specifically, the first sub-segment, arranged in parallel, adopts a straight-line design, reducing the risk of weld breakage and further decreasing the probability of print breakage, thus ensuring the stability of the connection. The expanded design of the second sub-line 412 visually enhances the offset of the weld strip. Since the branching line 410 in this example is made with sub-grid paste, the high mesh count screen reduces the possibility of breakage during the printing of diagonal lines.

[0103] In one example, the line width of the fork line 410 is 0.03mm-0.06mm. Exemplary examples include line widths of 0.03mm, 0.04mm, 0.05mm, etc.

[0104] In this embodiment, both the branch line 410 and the auxiliary line 420 are printed using fine grid 310 paste. Since the resistivity of fine grid 310 paste is less than that of the main grid paste, after testing, the volume resistivity of the main grid paste is 3.4 μΩ·cm, while the volume resistivity of the sub-grid paste is 2.0 μΩ·cm. This can reduce the resistance loss of current transmission in the first connection structure 400. Roughly calculated, by replacing the main grid paste with sub-grid paste, the power loss at the first connection structure 400 can be reduced by 30%.

[0105] In some embodiments, the solar cell further includes a second main grid, a second sub-grid, and a second connection structure. The second main grid, the second sub-grid, and the second connection structure are disposed on a second surface, and the second main grid has the same structure as the first main grid 200, the second sub-grid has the same structure as the first sub-grid 300, and the second connection structure has the same structure as the first connection structure 400.

[0106] It is understood that in this embodiment, all electrode structures on the first surface are symmetrically applied to the second surface of the battery. That is, both sides of the battery substrate 100 have the same main grid, sub-grid, and connection structure design. When the solder ribbon extends from the front of one battery to the back of another battery, based on edge passivation and the connection structure, the battery power can be improved while ensuring that the lamination does not break.

[0107] Based on the same concept, this application also provides a solar module, including multiple solar cells as described in the above embodiments, with the multiple solar cells connected together by solder strips.

[0108] It is understood that the solar cells in the above embodiments are connected in series to form a cell string by soldering ribbons. Specifically, this involves placing the solder ribbon on the pad 220 of the first surface of a solar cell, heating it with a welding device to form a reliable metallurgical bond between the solder ribbon and the metal paste on the pad 220. The other end of the solder ribbon is then welded to the pad 220 of the second surface of the adjacent solar cell in the same manner, and this process is repeated. Because the cell metallization pattern in this embodiment is optimized for the edge passivation process, the traditional heavy harpoon design is eliminated, resulting in a significant reduction in the stacking height of the metal paste under the solder ribbon. During module lamination, this effectively avoids microcracks or cell breakage caused by local stress concentration, greatly improving the module's production yield and long-term mechanical reliability.

[0109] Meanwhile, thanks to the through-hole design of the cell edge grid 310 and the efficient current collection and conduction of the first connection structure 400, the edge area that would have lost power due to disconnection can effectively contribute current, thereby improving the power of each cell and ultimately integrating it into the module, which is reflected as an effective gain in the overall power of the module.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A solar cell, characterized in that, The solar cell includes: The battery substrate (100) includes a first surface and a second surface disposed opposite to each other, and the edge of the first surface has a passivation region (101). A first main gate (200) is disposed on the first surface. The first main gate (200) includes a fine main gate (210) and pads (220) spaced apart on the fine main gate (210). The pads (220) are provided at both ends of the length direction of the fine main gate (210). The first sub-gate (300) is disposed on the first surface. The first sub-gate (300) includes a plurality of parallel and spaced fine gates (310), and some of the fine gates (310) are connected to the pads (220) and intersect with the fine main gate (210); at least one of the plurality of fine gates (310) is located in the passivation region (101). A first connection structure (400) is disposed on the first surface and at both ends of the fine main gate (210) along its length. The first connection structure (400) includes a branch line (410) and an auxiliary line (420). One end of the branch line (410) is electrically connected to the first main gate (200), and the other end extends away from the fine main gate (210) and is electrically connected to the fine gate (310) located in the passivation region (101). The auxiliary line (420) is located in the passivation region (101) and is electrically connected to the branch line (410) on the same fine gate (310).

2. The solar cell according to claim 1, characterized in that, The first connection structure (400) includes at least one of the auxiliary lines (420), which is perpendicular to the fine grid (310); The first connection structure (400) includes two branch lines (410), which are located on opposite sides of the pad (220) along the extension direction of the fine gate (310); And / or, the fine main gate (210) is perpendicular to the fine gate (310).

3. The solar cell according to claim 2, characterized in that, The first connection structure (400) includes an auxiliary line (420); The passivation region (101) has at least two fine grids (310), one end of the auxiliary line (420) is electrically connected to one of the fine grids (310) near the edge of the battery substrate (100), and the other end is electrically connected to one of the fine grids (310) away from the edge of the battery substrate (100).

4. The solar cell according to claim 3, characterized in that, The auxiliary line (420), the branch line (410), and the first main grid (200) are integrally formed by silver paste printing; And / or, the line width of the auxiliary line (420) is 0.03mm-0.06mm.

5. The solar cell according to claim 2, characterized in that, The first connection structure (400) includes multiple auxiliary lines (420); The passivation region (101) has at least two fine grids (310), and at least one fine grid (310) near the edge of the battery substrate (100) includes a first sub-grid and a second sub-grid that are spaced apart; one of the plurality of auxiliary lines (420) is electrically connected to the ends of all the first sub-grids, and the other of the plurality of auxiliary lines (420) is electrically connected to the ends of all the second sub-grids.

6. The solar cell according to claim 5, characterized in that, An auxiliary line (420) located between the first sub-grid and the second sub-grid is defined as a sub-auxiliary line. One end of the sub-auxiliary line is electrically connected to a continuous fine grid (310) away from the edge of the battery substrate (100), and the other end is flush with a fine grid (310) near the edge of the battery substrate (100).

7. The solar cell according to claim 6, characterized in that, The spacing between two adjacent auxiliary lines (420) is equal to the spacing between two adjacent fine grids (310); And / or, along the extension direction of the fine gate (310), the ratio of the sum of the spacings of all the auxiliary lines (420) to the width of the pad (220) is greater than or equal to 1.5; And / or, the line width of the auxiliary line (420) is 0.02mm-0.04mm.

8. The solar cell according to any one of claims 5-7, characterized in that, The auxiliary line (420) and the fine grid (310) are integrated by silver paste printing, and the branch line (410) and the first main grid (200) are integrated by silver paste printing.

9. The solar cell according to any one of claims 3-7, characterized in that, The two bifurcation lines (410) are parallel to each other, and the bifurcation lines (410) are perpendicular to the fine grid (310); And / or, the ratio of the distance between the two bifurcated lines (410) to the width of the pad (220) along the extension direction of the fine gate (310) is 1.2-1.5; And / or, the line width of the bifurcation line (410) is 0.03mm-0.06mm; And / or, one end of the branch line (410) away from the auxiliary line (420) is electrically connected to the fine gate (310) connected to the pad (220), or, one end of the branch line (410) away from the auxiliary line (420) is electrically connected to the pad (220).

10. The solar cell according to any one of claims 5-7, characterized in that, The auxiliary line (420), the branch line (410), and the fine grid (310) are integrated by silver paste printing.

11. The solar cell according to claim 10, characterized in that, The branch line (410) includes a first sub-line (411) and a second sub-line (412) connected in sequence in the direction away from the fine main gate (210). The two first sub-lines (411) are arranged parallel to each other, and the end of the first sub-line (411) away from the second sub-line (412) is electrically connected to the pad (220). The spacing between the two second sub-lines (412) gradually increases in the direction away from the pad (220), and the end of the second sub-line (412) away from the first sub-line (411) is electrically connected to the fine gate (310) located in the passivation region; And / or, the line width of the bifurcation line (410) is 0.03mm-0.06mm.

12. The solar cell according to any one of claims 1-7, 11, characterized in that, The solar cell further includes a second main grid, a second sub-grid, and a second connection structure. The second main grid, the second sub-grid, and the second connection structure are disposed on the second surface. The second main grid has the same structure as the first main grid (200), the second sub-grid has the same structure as the first sub-grid (300), and the second connection structure has the same structure as the first connection structure (400).

13. A solar energy module, characterized in that, It includes a plurality of solar cells as described in any one of claims 1-12, wherein the plurality of solar cells are connected to each other by solder strips.

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