Photovoltaic cell and photovoltaic module

Abstract

The application relates to the photovoltaic field, and provides a photovoltaic cell and a photovoltaic module. The photovoltaic cell comprises a body, the surface of the body is provided with fine grids, pads and connecting grid lines, a plurality of fine grids are distributed at intervals in a first direction, the pads are electrically connected with the fine grids; and the connecting grid lines extend along the first direction and are electrically connected with at least two fine grids. When the connection between one pad and a solder strip fails, the current on the fine grid electrically connected with the pad can flow to an adjacent fine grid through the connecting grid line, and then flow to the solder strip through the pad electrically connected with the fine grid. The connecting grid line is arranged, so that the current transmission loss of the photovoltaic cell is reduced when the connection between the pad and the solder strip fails, the output power of the photovoltaic cell is improved, and the situation that a local black spot or dark strip appears in an electroluminescence detection image of the photovoltaic cell is improved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, specifically to a photovoltaic cell and a photovoltaic module. Background Technology

[0002] Photovoltaic cells have a grid and pads. The pads are electrically connected to the grid and are used to transfer the current on the grid to the solder ribbon, which is electrically connected to the pads. However, existing photovoltaic cell structures have a defect: when the connection between the pads and the solder ribbon fails, the current on the grid, which is electrically connected to the pad, cannot be collected by the solder ribbon, resulting in a reduction in the output power of the photovoltaic cell. Summary of the Invention

[0003] In view of this, this application provides a photovoltaic cell and a photovoltaic module to solve the problem in the prior art where the failure of the connection between the solder pads and the solder ribbon leads to the inability to collect fine grid current.

[0004] This application provides a photovoltaic cell, including a body, the surface of which is provided with fine grids, pads and connecting grid lines; a plurality of fine grids are spaced apart in a first direction, the pads are electrically connected to the fine grids; the connecting grid lines extend along the first direction and are electrically connected to at least two of the fine grids.

[0005] The beneficial effects of the above scheme are as follows: the connecting grid lines can transmit current between adjacent fine grids. When the connection between one pad and the solder ribbon fails, the current on the fine grid electrically connected to that pad can flow through the connecting grid lines to another adjacent fine grid, and then through the pad electrically connected to that fine grid to the solder ribbon. Compared to the current flowing through the fine grid to other adjacent pads along the second direction, the connecting grid lines can provide a shorter flow path, which helps to reduce the equivalent series resistance of the photovoltaic cell, thereby improving the fill factor and output power of the photovoltaic cell. Therefore, setting connecting grid lines helps to reduce the current transmission loss of the photovoltaic cell when the connection between the pad and the solder ribbon fails, and improves the output power of the photovoltaic cell. The above structure can improve the situation where local black spots or dark bars appear in the electroluminescence (EL) detection image of the photovoltaic cell.

[0006] This application provides a photovoltaic module, including a solder strip and the photovoltaic cells described above, wherein two adjacent photovoltaic cells along the first direction are electrically connected by the solder strip.

[0007] The beneficial effects of the above scheme are as follows: when the connection between one of the pads and the solder strip fails, the current on the fine grid that is electrically connected to the pad can flow through the connecting grid line to another adjacent fine grid, and then through the pad that is electrically connected to this fine grid to the solder strip, which is beneficial to improving the output power of the photovoltaic module. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a partial structural diagram of the photovoltaic cell provided in the first embodiment of this application; Figure 2 This is a partial structural diagram of the photovoltaic cell provided in the first embodiment of this application; Figure 3 A partial structural schematic diagram of the photovoltaic cell provided in the embodiments of this application in a third embodiment; Figure 4 A partial structural schematic diagram of the photovoltaic cell provided in the embodiments of this application in the fourth embodiment; Figure 5 This is a schematic diagram of the structure of the photovoltaic module provided in the embodiments of this application; Figure 6 for Figure 5 A schematic diagram of a partial structure of a photovoltaic module from another perspective.

[0010] Figure label: 10- Photovoltaic cells; 20-Welding strip; 30 - Adhesive components; 40-front plate; 50 - Front encapsulation layer; 60 - Backside encapsulation layer; 70 - Backplate; 1-Ontology; 2-Fine grid; 3-Pads; 4-Connecting grid lines; 5-Main gate. Detailed Implementation

[0011] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0012] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0013] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0014] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0015] In the accompanying drawings corresponding to the embodiments of this application, for clarity, the proportions of structures such as layers, films, and regions may not be proportions of actual structures. It should be understood that when it is mentioned that feature a (e.g., layer, film, region, or substrate) is "located" "on" feature b, feature a may be directly located on feature b, or there may be other features c between feature a and feature b. Conversely, when it is mentioned that feature a is "directly located" "on" feature b, it means that there are no other features between feature a and feature b.

[0016] In the description of the embodiments of this application, the meaning of "electrical connection" may include: after two structures with conductive properties are physically connected, under the action of an electric field, one of the two physically connected structures with conductive properties can conduct electricity to the other. The physical connection for conducting electricity can be a direct connection or an indirect connection through other conductive media.

[0017] In the description of the embodiments of this application, the use of terms such as "same," "equal," or "consistent" regarding dimensions does not require absolute mathematical or geometric precision. Given the actual manufacturing, measurement, and material factors, those skilled in the art should understand that the aforementioned dimensional terms include deviations within permissible limits or unavoidable deviations. As long as such deviations do not affect the functionality and technical effects of the corresponding dimensions in this application, they should be considered to fall within the meaning of "same dimensions" as described in the embodiments of this application.

[0018] This application provides a photovoltaic cell 10, such as... Figure 1As shown, the photovoltaic cell 10 includes a body 1, the surface of which is provided with fine grids 2, pads 3, and connecting grid lines 4. Multiple fine grids 2 are spaced apart in a first direction X, and each fine grid 2 extends along a second direction Y, used to collect and guide the photocurrent generated in the body 1. Each fine grid 2 is electrically connected to a corresponding pad 3, the pad 3 having the same polarity as the fine grid 2, used to collect the current on the fine grid 2. The pads 3 are also used to connect to solder ribbons to achieve series connection between adjacent photovoltaic cells 10 and to guide the current of the photovoltaic cells 10 outwards. Multiple pads 3 aligned along the first direction X form a pad group, used for electrical connection with the same solder ribbon. Along the second direction Y, the body 1 has multiple spaced pad groups, meaning each fine grid 2 can be electrically connected to multiple pads 3 spaced apart along the second direction Y, and the current of the photovoltaic cell 10 can be guided outwards through multiple solder ribbons electrically connected to multiple pad groups.

[0019] The connecting grid line 4 extends along the first direction X and is electrically connected to at least two fine grids 2. The connecting grid line 4 allows current transfer between adjacent fine grids 2. When the connection between one pad 3 and the solder ribbon fails, the current on the fine grid 2 electrically connected to that pad 3 can flow through the connecting grid line 4 to another adjacent fine grid 2, and then through the pad 3 electrically connected to that fine grid 2 to the solder ribbon. Compared to the current flowing through the fine grid 2 to other adjacent pads 3 along the second direction Y, the connecting grid line 4 provides a shorter flow path, which helps reduce the equivalent series resistance of the photovoltaic cell 10, thereby improving the fill factor and output power of the photovoltaic cell 10. Therefore, setting the connecting grid line 4 helps reduce the current transfer loss of the photovoltaic cell 10 when the connection between the pad 3 and the solder ribbon fails, improving the output power of the photovoltaic cell 10. The above structure can improve the situation where local black spots or dark bars appear in the electroluminescence (EL) detection image of the photovoltaic cell 10.

[0020] It should be noted that the first direction X intersects with the second direction Y, as shown below. Figure 1 As shown, one of the first direction X and the second direction Y can be the length direction of the photovoltaic cell 10, and the other can be the width direction of the photovoltaic cell 10.

[0021] In this embodiment, the connecting gate line 4 can be electrically connected to two, three, four or more fine gates 2. This application embodiment does not limit the number of fine gates 2 electrically connected to the connecting gate line 4.

[0022] Optionally, multiple spaced connecting grid lines 4 can be provided in the first direction X, and the number of fine grids 2 electrically connected to each connecting grid line 4 can be equal or unequal.

[0023] Optionally, a whole connecting grid line 4 can be provided in the first direction X, that is, the connecting grid line 4 is electrically connected to each fine grid 2 of the photovoltaic cell 10.

[0024] In some embodiments, such as Figure 1 As shown, the connecting grid line 4 can be electrically connected to three fine grids 2. When the connection between one of the pads 3 and the solder strip fails, the current on the fine grid 2 electrically connected to that pad 3 can flow through the connecting grid line 4 to the other two fine grids 2, and then through the pads 3 electrically connected to these two fine grids 2 to the solder strip. In particular, when the connection between the middle pad 3 and the solder strip fails, the current on the fine grid 2 electrically connected to that pad 3 can be symmetrically diverted through the connecting grid line 4 to the other two fine grids 2. The flow paths of the two currents formed by the diversion are equal (both are the spacing between adjacent fine grids 2), and the equivalent resistance after parallel connection is minimized. This diversion makes the current distribution in the area around the failed pad 3 more uniform, avoiding current concentration on a section of the connecting grid line 4, which helps reduce the risk of local overheating of the photovoltaic cell 10.

[0025] Moreover, if the connection between two of the pads 3 and the solder ribbon fails, the current on the two fine grids 2 that are electrically connected to the two pads 3 can flow to the other third fine grid 2 through the connecting grid line 4, which improves the electrical reliability of the photovoltaic cell 10 and helps to reduce the current transmission loss of the photovoltaic cell 10.

[0026] In some embodiments, such as Figure 1 As shown, along the second direction Y, connecting grid lines 4 are respectively provided on both sides of the pad 3, and the connecting grid lines 4 on both sides correspond to the fine grids 2 electrically connected to the pad 3 on both sides. When one of the pads 3 fails, the current on the fine grids 2 on both sides of the pad 3 can flow to the adjacent fine grids 2 through the nearest connecting grid line 4, so as to ensure that the current on both sides of the fine grids 2 can be collected along a shorter path, which helps to reduce the circuit transmission loss of the photovoltaic cell 10.

[0027] Optionally, the distance between the connecting grid lines 4 on both sides of the pad 3 is equal to the distance between the pad 3 and the pad 3. When the connecting grid lines 4 on both sides of the failed pad 3 carry current simultaneously, the current flow paths on both sides of the pad 3 are equal, making the current distribution in the area around the pad 3 more uniform, which helps to reduce the risk of local overheating of the photovoltaic cell 10.

[0028] Furthermore, when connecting grid lines 4 are provided on both sides of the pad 3, if the connecting grid line 4 on one side fails due to breakage or other reasons, the connecting grid line 4 on the other side can still ensure the electrical connection between the two adjacent fine grids 2, which is beneficial to improving the electrical reliability of the photovoltaic cell 10.

[0029] In some embodiments, such as Figure 1As shown, the width of the thin grid lines 2 may be uniform, that is, along the second direction Y, the width of the thin grid lines 2 is equal everywhere.

[0030] In some other embodiments, as Figure 2 shown, the width of the thin grid lines 2 may be variable. The thin grid line 2 comprises a widened portion 21 and a main body portion 22. One end of the widened portion 21 is electrically connected to the pad 3, and the other end is electrically connected to the connecting grid line 4. The main body portion 22 is located at an end of the widened portion 21 away from the pad 3. Providing the widened portion 21 is equivalent to widening the part of the thin grid line 2 connecting the pad 3 and the connecting grid line 4, that is, compared with the main body portion 22, the widened portion 21 has a larger width and a larger cross-sectional area, so that the resistance of the widened portion 21 is smaller, which can reduce the current transmission loss, thereby helping to improve the output power of the photovoltaic cell sheet 10. Moreover, the reduction of the resistance of the widened portion 21 helps to alleviate the problem of overheating of the thin grid lines 2 on both sides of the pad 3 caused by excessively high local current density, which is beneficial to improving the electrical reliability and service life of the photovoltaic cell sheet 10.

[0031] Wherein, as Figure 2 shown, among the thin grid lines 2 connected to the connecting grid lines 4, only part of the thin grid lines 2 may be provided with the widened portion 21. Alternatively, each thin grid line 2 connected to the connecting grid line 4 may be provided with the widened portion 21, which is not limited in the embodiments of the present application.

[0032] In some embodiments, along the first direction X, the width of the main body portion 22 is W1, the width of the widened portion 21 is W2, and W1<W2≤2W1. When the width W2 of the widened portion 21 satisfies the above range, the widened portion 21 can achieve the effect of reducing current transmission loss, and can avoid the problem that the excessively large shading area of the widened portion 21 affects the photoelectric conversion efficiency of the photovoltaic cell sheet 10. In addition, the amount of paste for the widened portion 21 can be appropriately reduced, which is beneficial to reducing the preparation cost of the photovoltaic cell sheet 10.

[0033] Optionally, the ratio of W2 to W1 may be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2, and may also be other values within the above range, which is not limited in the embodiments of the present application.

[0034] In some embodiments, as Figure 2 shown, the width of the widened portion 21 may be uniform, that is, along the second direction Y, the width of the widened portion 21 is equal everywhere.

[0035] In some other embodiments, as Figure 3As shown, the width of the widened portion 21 can be varied. Along the second direction Y, the width of the end of the widened portion 21 electrically connected to the pad 3 is D1, and the width of the end of the widened portion 21 electrically connected to the connecting gate line 4 is D2, where D1 > D2. The wider end of the widened portion 21 near the pad 3 has a smaller resistance, which helps to reduce current transmission loss. The narrower width of the end of the widened portion 21 near the connecting gate line 4 helps to further reduce the amount of paste used in the widened portion 21 and reduce the light-shielding area of ​​the widened portion 21.

[0036] Among them, such as Figure 3 As shown, the widened portion 21 can be triangular, meaning the width of the widened portion 21 can gradually increase along the second direction Y towards the pad 3. Alternatively, the widened portion 21 can also be trapezoidal or other shapes; this embodiment does not limit this.

[0037] Among them, such as Figure 3 As shown, in the fine gates 2 connected to the connecting gate line 4, only the width of the widened portion 21 of some fine gates 2 may vary. Alternatively, the width of each fine gate 2 connected to the connecting gate line 4 may vary; this embodiment does not impose any limitations on this.

[0038] In some embodiments, such as Figure 1 As shown, along the second direction Y, the distance between the midpoints of two adjacent pads 3 is S, and the distance between the midpoint of pad 3 and the connecting gate line 4 is L.

[0039] In some embodiments, such as Figure 1 As shown, pad 3 has an I-shaped structure, with wider ends along the first direction X. The wider ends of pad 3 provide greater process tolerance for alignment between pad 3 and the fine grid 2. Specifically, even if the fine grid 2 or pad 3 is offset by a certain distance along the first direction X during printing, the wider ends of pad 3 can still ensure a stable electrical connection between the fine grid 2 and pad 3, thereby improving the yield of the photovoltaic cell 10. The narrower middle portion of pad 3 reduces the shading area and the amount of paste used in pad 3, thus improving the photoelectric conversion efficiency of the photovoltaic cell 10 and reducing its manufacturing cost.

[0040] In some embodiments, such as Figures 1-3 ​As shown, the photovoltaic cell 10 can be a gridless cell. The current on the fine grid 2 flows through the pads 3 to the solder ribbon electrically connected to the pads 3.

[0041] In some embodiments, the photovoltaic cell 10 may also be a cell with a main busbar. For example... Figure 4 As shown, the surface of the main body 1 is also provided with a main grid 5, which extends along the first direction X. The main grid 5 is electrically connected to multiple pads 3, allowing current transmission between adjacent pads 3. The main grid 5 can be a single structure extending along the first direction X, or it can be a multi-segment structure spaced apart along the first direction X. The number of pads 3 electrically connected to each segment of the main grid 5 can be equal or unequal. The photovoltaic cell 10 may include multiple main grids 5 spaced apart along the second direction Y.

[0042] In some embodiments, the photovoltaic cell 10 can be a sliced ​​cell, specifically a two-slice cell, a three-slice cell, a four-slice cell, or an eight-slice cell. This application does not limit this.

[0043] In this embodiment, the photovoltaic cell 10 is a bifacial cell. The surface of the photovoltaic cell 10 includes a light-facing surface and a back-light-facing surface that are relatively distributed along its thickness direction Z. The fine grid 2 includes a first fine grid disposed on the light-facing surface and a second fine grid disposed on the back-light-facing surface. One of the first fine grid and the second fine grid is a positive electrode fine grid, and the other is a negative electrode fine grid. The pad 3 includes a first pad disposed on the light-facing surface and a second pad disposed on the back-light-facing surface. The connecting grid line 4 includes a first connecting grid line disposed on the light-facing surface and a second connecting grid line disposed on the back-light-facing surface. The first pad and the first connecting grid line have the same polarity as the first fine grid, and the second pad and the second connecting grid line have the same polarity as the second fine grid.

[0044] This embodiment does not limit the type of photovoltaic cell 10. The types of photovoltaic cell 10 include, but are not limited to, passivated emitter rear cell (PERC), tunnel oxide passivated contact (TOPCon), intrinsic thin-film heterojunction (HJT), perovskite cell, etc.

[0045] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front-surface silver electrode, a front-surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type substrate silicon layer, a localized aluminum back field, a metallic aluminum back electrode, and a back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back side, replacing the all-aluminum back field, enhancing light reflection within the silicon substrate, reducing the recombination rate on the back side, and improving the cell efficiency by 0.5%-1%.

[0046] For TOPCon cells, along their thickness direction, the TOPCon cell sequentially includes a silver electrode, a front-surface silicon nitride passivation layer, a boron-doped emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and the silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure can block minority carrier recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes band bending on the silicon wafer surface, resulting in a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby increasing the cell's conversion efficiency.

[0047] For an HJT cell, along its thickness direction, the HJT cell sequentially includes a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type substrate silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0048] For a perovskite solar cell, along its thickness direction, it sequentially comprises a substrate material, a conductive thin film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials possess a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with minimal loss, thus generating high photogenerated voltage and current, resulting in high photoelectric conversion efficiency.

[0049] This application also provides a photovoltaic module, such as... Figure 5 As shown, the photovoltaic module includes multiple photovoltaic cells 10 and solder ribbons 20. Along the first direction X, the multiple photovoltaic cells 10 are connected in series by solder ribbons 20 to form a cell string. The same solder ribbon 20 is electrically connected to the solder pads 3 on two adjacent photovoltaic cells 10. The multiple cell strings are connected in series or in parallel through busbars to form a complete photovoltaic module.

[0050] When the connection between one of the pads 3 of the photovoltaic cell 10 and the ribbon 20 fails, the current on the fine grid 2 that is electrically connected to the pad 3 can flow through the connecting grid line 4 to another adjacent fine grid 2, and then through the pad 3 that is electrically connected to this fine grid 2 to the ribbon 20, which is beneficial to improving the output power of the photovoltaic module.

[0051] like Figure 5 As shown, the photovoltaic module also includes a front panel 40, a front encapsulation layer 50, a back encapsulation layer 60, and a back sheet 70. The front panel 40 and the back sheet 70 together sandwich the front encapsulation layer 50, the photovoltaic cell 10, the solder ribbon 20, and the back encapsulation layer 60, and form a photovoltaic module through lamination. The front encapsulation layer 50 protects the light-facing side of the photovoltaic cell 10, and the back encapsulation layer 60 protects the back-facing side of the photovoltaic cell 10. During the lamination process of the photovoltaic module, the front encapsulation layer 50 and the back encapsulation layer 60 encapsulate and protect the photovoltaic cell 10 and the solder ribbon 20, preventing external environmental factors from affecting their performance. They also bond the front panel 40, the back sheet 70, the photovoltaic cell 10, and the solder ribbon 20 into a single unit.

[0052] The front panel 40 and the back panel 70 can be made of light-transmitting materials. The materials of the front panel 40 and the back panel 70 can be one of rigid materials such as tempered glass, polyethylene terephthalate (PET), and polycarbonate (PC), or one of flexible materials such as polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF). The front encapsulation layer 50 and the back encapsulation layer 60 are adhesive films. The material of the adhesive film can be one of the following: ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB), etc. The front encapsulation layer 50 and the back encapsulation layer 60 can also be EPE adhesive film (EVA-POE-EVA co-extrusion structure) or EP adhesive film (EVA-POE co-extrusion structure). The materials of the front encapsulation layer 50 and the back encapsulation layer 60 can be the same or different.

[0053] The front panel 40 may have a raised or recessed structure on the side facing the front encapsulation layer 50 to increase the utilization rate of incident light. Similarly, the back panel 70 may also have a raised or recessed structure on the side facing the back encapsulation layer 60 to increase the utilization rate of incident light.

[0054] In some embodiments, the photovoltaic module can be electrically connected to the photovoltaic cell 10 using a low-temperature welding method. For example... Figure 6 As shown, the solder ribbon 20 is fixedly connected to the body 1 by an adhesive 30. Along the first direction X, the adhesive 30 is located between two adjacent fine grids 2. The solder ribbon 20 can be pre-fixed to the photovoltaic cell 10 through the adhesive 30. The low-temperature solder on the solder pad 3 melts during the lamination process using the heating temperature of the lamination to complete the welding and fixing of the solder pad 3 and the solder ribbon 20, so that the solder pad 3 and the solder ribbon 20 are electrically connected. The low-temperature welding method can reduce the thermal stress of the photovoltaic cell 10, thereby reducing the risk of microcracks in the body 1 due to uneven thermal expansion caused by local high temperature. It also reduces the risk of warping of the body 1 due to the tension of the solder ribbon 20 caused by the difference in thermal expansion coefficients between the solder ribbon 20 and the body 1. This is beneficial to improving the structural reliability of the photovoltaic module, thereby improving the product yield and service life of the photovoltaic module.

[0055] In addition, the surface of the solder ribbon 20 may be covered with a fixing film (not shown in the figure). The fixing film can shrink when heated during the lamination process, thereby restricting the movement of the solder ribbon 20 relative to the body 1, and thus assisting in fixing the solder ribbon 20. The fixing film can be a large film that can cover all the solder ribbons 20 on the battery string at the same time, or a small film that can cover all the solder ribbons 20 on each photovoltaic cell 10, or a strip film that can cover each solder ribbon 20 individually. In this embodiment, the shape and size of the fixing film are not limited. Specifically, the fixing film can be an insulating film, and its material can be the same as the material of the front encapsulation layer 50 and the back encapsulation layer 60. In this embodiment, the material of the fixing film is not limited.

[0056] In some embodiments, along the first direction X, 2-10 adhesive pieces 30 can be bonded and fixed to the same welding ribbon 20 to ensure the reliability of the connection between the welding ribbon 20 and the body 1. The number of adhesive pieces 30 can be 2, 3, 4, 5, 6, 7, 8, 9 or 10, and this application embodiment does not limit this.

[0057] In this embodiment, the adhesive 30 can be an insulating adhesive, or it can be applied by dispensing. Specifically, the solder ribbon 20 is first placed on the surface of the body 1 so that the position of the solder ribbon 20 corresponds to that of the solder pad 3. Then, adhesive is dispensed onto the surface of the solder ribbon 20 away from the body 1. The adhesive itself is fluid and can flow from both sides of the solder ribbon 20 to the body 1. After solidification, the adhesive forms the adhesive 30, which can bond and fix the solder ribbon 20 to the surface of the body 1.

[0058] The adhesive 30 should be positioned away from the pad 3. However, due to the fluidity of the adhesive, it may flow under the solder ribbon 20. When the insulating adhesive comes into contact with the pad 3 adjacent to the dispensing position, it will cause the connection between the pad 3 and the solder ribbon 20 to fail, thereby preventing the current on the fine gate 2 electrically connected to the pad 3 from being collected by the solder ribbon 20.

[0059] To avoid the above situation, the connecting grid line 4 can be positioned at the position corresponding to the adhesive 30, along the first direction X, such as... Figure 6 As shown, the connecting grid line 4 is electrically connected to at least the fine grids 2 located on both sides of the adhesive 30. Thus, when the adhesive seeps into the space between one of the pads 3 and the solder ribbon 20, causing the adhesive 30 to fail in connecting the pad 3 and the solder ribbon 20, the current on the fine grid 2 electrically connected to that pad 3 can flow through the connecting grid line 4 to the adjacent fine grid 2, and then through the pad 3 electrically connected to this fine grid 2 to the solder ribbon 20.

[0060] Optionally, in addition to being electrically connected to the fine grids 2 on both sides of the adhesive 30, the connecting grid line 4 can also be electrically connected to another adjacent fine grid 2, that is, the connecting grid line 4 connects to three adjacent fine grids 2 simultaneously. When the adhesive 30 causes the pads 3 on both sides to fail to connect with the solder ribbon 20, the current on the fine grid 2 electrically connected to these two pads 3 can flow through the connecting grid line 4 to the third fine grid 2, and then through the pads 3 electrically connected to this fine grid 2 to the solder ribbon. This helps to improve the electrical reliability of the photovoltaic module, thereby increasing the output power of the photovoltaic module.

[0061] In some embodiments, such as Figure 6 As shown, along the second direction Y, the distance between the midpoints of two adjacent pads 3 is S, the distance between the midpoint of pad 3 and the connecting gate line 4 is L, the width of solder strip 20 is A, and the offset of solder strip 20 in the second direction Y is B, where A+B≤L.

[0062] ​On the other hand, maintaining a certain distance between the connecting grid line 4 and the solder ribbon 20 and the adhesive 30 helps to ensure the heat dissipation capacity of the connecting grid line 4, reduces the risk of local overheating of the photovoltaic cell 10, and helps to improve the service life of the photovoltaic cell 10.

[0063] In summary, by providing connecting grid lines 4 at corresponding positions on the adhesive 30, when the adhesive 30 penetrates between the solder ribbon 20 and the solder pad 3, causing the connection between the solder pad 3 and the solder ribbon 20 to fail, the current on the fine grid 2 electrically connected to the failed solder pad 3 is transferred to another adjacent fine grid 2, and then transferred to the solder ribbon 20 through the solder pad 3 electrically connected to the fine grid 2. This helps to reduce the current transmission loss of the photovoltaic cell 10, and thus helps to improve the output power of the photovoltaic module.

[0064] It is understandable that the area where the adhesive 30 is not provided can also be provided with the connecting grid line 4. When the pad 3 fails to connect with the solder ribbon 20 for other reasons, the current on the fine grid 2 that is electrically connected to the pad 3 can flow to the adjacent fine grid 2 through the connecting grid line 4.

[0065] The above description is merely a preferred embodiment of this application and is not intended to limit the application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. Alternatively, the scope of this application is defined by the appended claims.

Claims

1. A photovoltaic cell, characterized in that, Includes a body, the surface of which is provided with fine gates, pads and connecting gate lines; Multiple fine gates are spaced apart in a first direction, and the pads are electrically connected to the fine gates; The connecting gate line extends along the first direction and is electrically connected to at least two of the fine gates.

2. The photovoltaic cell according to claim 1, characterized in that, Along the second direction, the connecting gate lines are respectively provided on both sides of the pad; The second direction intersects with the first direction.

3. The photovoltaic cell according to claim 1, characterized in that, The connecting gate line is electrically connected to the three fine gates.

4. The photovoltaic cell according to claim 1, characterized in that, The fine gate includes a widened portion, one end of which is electrically connected to a pad and the other end of which is electrically connected to the connecting gate line.

5. The photovoltaic cell according to claim 4, characterized in that, The fine gate also includes a main body portion, which is located at the end of the widened portion away from the pad; Along the first direction, the width of the main body is W1, and the width of the widened portion is W2, W1 <W2≤2W1。 6. The photovoltaic cell according to claim 4, characterized in that, The width of the end of the widened portion that is electrically connected to the pad is D1, and the width of the end of the widened portion that is electrically connected to the connecting gate line is D2, where D1>D2.

7. The photovoltaic cell according to claim 1, characterized in that, The plurality of pads are spaced apart along the second direction, and the distance between the midpoints of two adjacent pads in the second direction is S; The distance between the midpoint of the pad and the connecting gate line in the second direction is L, where L is the distance between the second direction and the first direction. The surface of the body is also provided with a main gate, which extends along the first direction and is electrically connected to the pad.

8. The photovoltaic cell according to claim 1, characterized in that, include:

9. A photovoltaic module, characterized in that, The photovoltaic cell is the photovoltaic cell according to any one of claims 1-8; The welding strip connects two adjacent photovoltaic cells along the first direction electrically. The welding strip is fixedly connected to the body by an adhesive, which is located between two adjacent fine grids; 10. The photovoltaic module according to claim 9, characterized in that, The connecting grid line is electrically connected to the fine grid located on both sides of the adhesive. The plurality of pads are spaced apart along the second direction, and the distance between the midpoints of two adjacent pads in the second direction is S; 11. The photovoltaic module according to claim 9, characterized in that, The distance between the midpoint of the pad and the connecting gate line in the second direction is L; The width of the solder strip is A, and the offset of the solder strip in the second direction is B, where A+B≤L. The second direction intersects with the first direction. ​ ​

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