Solar cell and photovoltaic module

Abstract

The invention discloses a solar cell and a photovoltaic module, relates to the technical field of solar cells, and aims to solve the problem of how to improve the photoelectric conversion efficiency of the solar cell. The solar cell includes: a first passivation contact structure formed on a first side of a semiconductor substrate; a first bus electrode and a first collector electrode are formed over the first passivation contact structure; at least part of the first bus electrode comprises a first end bonding pad close to the first edge of the semiconductor substrate and at least two first sub bus electrodes connected to the first end bonding pad; the area between the two first sub bus electrodes located on the outermost side forms a first end bus electrode area. The first passivation contact structure is provided with a first hollow area and a second hollow area; the first hollow area is located in the first end bus electrode area; the second hollow area is located outside the first end bus electrode area and located between the first collector electrodes.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a photovoltaic module. Background Art

[0002] Solar cells are devices that utilize solar energy, converting it into electricity through the photovoltaic effect. These solar cells include tunnel oxide passivated contact solar cells (TOPCon). The backside of a TOPCon cell features a passivated contact structure consisting of a tunnel oxide layer and a doped polysilicon layer, improving the backside's passivation performance.

[0003] Since the doped polysilicon layer formed on the back side produces parasitic absorption of light, it will reduce the utilization rate of light, affecting the light utilization rate on the back side of the battery and the battery efficiency.

[0004] Therefore, how to improve the photoelectric conversion efficiency of solar cells is a technical problem that needs to be urgently solved in the current industry. Summary of the Invention

[0005] The object of the present invention is to provide a solar cell and a photovoltaic module for improving the photoelectric conversion efficiency of the solar cell.

[0006] In order to achieve the above-mentioned objectives, in a first aspect, the present invention provides a solar cell. The solar cell includes: a semiconductor substrate, a first passivation contact structure, a first bus electrode, and a first collector electrode. The semiconductor substrate includes a first surface and a second surface opposite to each other; along a first direction, the semiconductor substrate includes a first edge and a second edge opposite to each other; the first passivation contact structure is formed on the first surface of the semiconductor substrate; the first collector electrode is formed above the first passivation contact structure; a plurality of first collector electrodes extend along the second direction and are spaced apart along the first direction. The first bus electrode is formed above the first passivation contact structure; the first bus electrode intersects with the plurality of first collector electrodes. At least part of the first bus electrode includes: a first end pad close to the first edge and a first end bus electrode connected to the first end pad, the first end bus electrode being located between the first end pad and the first edge. The first end bus electrode includes at least two first sub-bus electrodes; the area between the two outermost first sub-bus electrodes constitutes the first end bus electrode area. The first passivation contact structure has a first hollow area and a second hollow area; the first hollow area is located in the first end bus electrode area; the second hollow area is located outside the first end bus electrode area and between the first collecting electrodes.

[0007] In the solar cell provided by the present invention, the first bus electrode is formed above the first passivation contact structure, and the first bus electrode is not in direct contact with the semiconductor substrate. In this case, the metal recombination of the solar cell can be reduced, the open circuit voltage of the solar cell can be increased, and the battery efficiency of the solar cell can be improved. Furthermore, since the first collector electrode is formed above the first passivation contact structure, the first collector electrode is electrically connected to the first passivation contact structure. At this time, not only can the contact resistivity be reduced, the series resistance can be reduced to effectively collect current, reduce electrical losses, and improve the battery efficiency of the solar cell. At the same time, the transmission distance of the carriers can also be reduced to reduce the recombination loss of the carriers during the transmission process. Furthermore, the first passivation contact structure has a first hollow area and a second hollow area, the first hollow area is located in the first end bus electrode area; the second hollow area is located outside the first end bus electrode area and is located between the first collector electrodes. The present application achieves dual optimization of optical performance and electrical performance by introducing the first hollow area in the first end bus electrode area. This design significantly improves the effective utilization of incident light by reducing light absorption losses in the cell's power generation area, allowing more photons to participate in the photoelectric conversion process. More importantly, the provision of a first hollow region within the first end busbar region solves the current collection mismatch problem present in existing technologies, namely the phenomenon of low efficiency in collecting photogenerated carriers in some areas due to uneven electric field distribution within the cell. By providing a matching relationship between the first hollow region within the first end busbar region and the second hollow region outside the first end busbar region, not only is the effective collection efficiency of carriers in the electrode region significantly improved, but non-radiative recombination losses are also effectively suppressed. This improves key performance parameters such as fill factor (FF) and open circuit voltage (Voc) while increasing short-circuit current (Jsc), ultimately achieving a significant improvement in the overall conversion efficiency of the solar cell.

[0008] In one implementation, at least part of the first bus electrode further includes: a first bus electrode connecting line, a plurality of first bus electrode connecting lines extending along the first direction and spaced apart along the second direction; and a first end pad disposed at one end of the first bus electrode connecting line close to the first edge.

[0009] In one implementation, the first hollow area and the second hollow area have equal widths in the first direction; the first hollow area has a first centerline extending along the second direction; and along the second direction, a second hollow area adjacent to the first hollow area has a second centerline extending along the second direction. The first center line and the second center line are collinear; and / or, along the first direction, the ratio of the distance between the first center line and the second center line to the width of the first hollow area along the first direction or to the width of the second hollow area along the first direction is less than or equal to 10%.

[0010] When the above technical solution is employed, the first and second hollow regions are formed after laser processing of the first passivation contact structure. If the above ratio is greater than 10%, it indicates that during the laser processing of the first passivation contact structure, the first hollow region is offset too much relative to the second hollow region in the first direction, or the second hollow region is offset too much relative to the first hollow region in the first direction. In this case, it is very likely that the first hollow region or the second hollow region is located below the first collector electrode, resulting in the interruption of the first passivation contact structure below the first collector electrode. In other words, the laser removal of the portion of the first passivation contact structure below the first collector electrode can easily cause the first collector electrode to be directly welded to the semiconductor substrate when the first collector electrode is subsequently formed, generating carrier recombination centers and metal recombination, reducing the short-circuit current and fill factor of the solar cell, and increasing the contact resistance.

[0011] In summary, when the ratio of the distance between the first center line and the second center line to the width of the first hollow area along the first direction or to the width of the second hollow area along the first direction is less than or equal to 10%, the first collecting electrode can be prevented from being directly welded to the semiconductor substrate, and the generation of carrier recombination centers and metal recombination can be avoided, thereby increasing the open circuit voltage of the solar cell, improving the short circuit current and fill factor of the solar cell, reducing the contact resistance, and thereby improving the cell efficiency of the solar cell.

[0012] In one implementation, the first end bus electrode region has a plurality of first hollow regions spaced apart along the first direction.

[0013] The above technical solution not only effectively reduces the shielding of the semiconductor substrate by the first passivation contact structure, but also reduces the parasitic absorption of light by the first passivation contact structure, reduces light absorption losses in the power generation area of ​​the cell, and reduces light energy loss, but also significantly improves the effective utilization rate of incident light, allowing more photons to be transmitted to the semiconductor substrate, thereby allowing more photons to participate in the photoelectric conversion process, and improving the photoelectric conversion efficiency of the solar cell. At the same time, it can also increase the carrier generation rate in the first end bus electrode region and reduce the recombination rate. Furthermore, it further solves the current collection mismatch problem existing in the prior art.

[0014] In one implementation, two adjacent first hollow areas are staggered in the first direction.

[0015] When the above technical solution is adopted, when the first hollow region is provided on the first passivation contact structure, the first hollow region will destroy the original stress distribution, and stress concentration is easily generated at the edge of the first hollow region. When two adjacent first hollow regions are staggered in the first direction, the stress can be dispersed in different directions, avoiding overlap of stress concentration regions and reducing the risk of local fracture. Furthermore, when the first collecting electrode and the first bus electrode are subsequently fabricated on the first passivation contact structure having the first hollow region, the probability of fracture of the first passivation contact structure corresponding to the first collecting electrode and the first bus electrode due to stress concentration can be reduced, thereby reducing or avoiding the generation of carrier recombination centers and metal recombination, thereby increasing the open circuit voltage of the solar cell, improving the short circuit current and fill factor of the solar cell, and thus improving the cell efficiency of the solar cell. In addition, the staggered arrangement of the two adjacent first hollow regions in the first direction can disperse processing errors, avoid the cumulative errors during processing causing the position deviations of all the first hollow regions to be superimposed along the first direction, thereby avoiding the processing errors exceeding the design errors, improving the fault tolerance rate, and thus improving the quality of the solar cell.

[0016] In one implementation, the distance between the two second hollow areas on both sides of the first end pad along the second direction is L1, and the distance between the two second hollow areas on both sides of the first bus electrode connection line along the second direction is L2, satisfying that L1 is greater than L2.

[0017] Using this technical solution, the removal of the corresponding first passivation contact structure beneath the first end pad can be reduced or avoided when forming the two second hollowed-out regions located on either side of the first end pad along the second direction, thereby reducing or avoiding direct contact between the first end pad and the underlying semiconductor substrate. This not only reduces or avoids the formation of recombination centers, improving minority carrier lifetime and battery open-circuit voltage, but also reduces contact resistance and improves current collection efficiency.

[0018] In one implementation, along the second direction, distances between the two second hollow regions located on both sides of the first bus electrode connecting line and the first bus electrode connecting line are not equal.

[0019] When the above-mentioned technical solution is adopted, when the photovoltaic module is subsequently formed, the conductive connecting parts such as the welding strip are welded to the first bus electrode connecting line. Since in this application, the distance between the two second hollow areas on both sides of the first bus electrode connecting line and the first bus electrode connecting line along the second direction is not equal, the stress concentration can be reduced at this time, and the mechanical strength of the conductive connecting parts such as the welding strip during welding can be improved.

[0020] In one implementation, along the second direction, the distance between a first hollow area and an adjacent second hollow area is L5, and the distance between two adjacent first hollow areas along the first direction is L6, satisfying that L5 is greater than L6.

[0021] When using the above technical solution, the first sub-bus electrode corresponds to the first passivation contact structure between the second hollow region adjacent to the first hollow region and the first hollow region, and the first collecting electrode corresponds to the first passivation contact structure between two adjacent first hollow regions. Because the first bus electrode has lower contact performance with the solar cell than the first collecting electrode; or because the first bus electrode needs to be soldered to a conductive connector such as a solder ribbon, the width of the first bus electrode is typically increased to increase the contact area with the solar cell surface or the conductive connector to improve the contact and soldering performance of the first bus electrode. Furthermore, because the first bus electrode includes the first sub-bus electrode, the first sub-bus electrode is relatively wide. Therefore, in this application, L5 is greater than L6. Furthermore, because the paste forming the first bus electrode has high ductility, the width of the first bus electrode is greater than the width of the first collecting electrode, that is, the width of the first sub-bus electrode is greater than the width of the first collecting electrode. Therefore, in this application, L5 is greater than L6 to improve the tolerance of printing offset of the first sub-bus electrode. In addition, the above solution can also reduce the parasitic absorption of light by the first passivation contact structure between two adjacent first hollow regions, thereby improving light utilization.

[0022] In one implementation, along the second direction, a distance between a first hollow region and an adjacent second hollow region is L5, satisfying 50 μm≤L5≤1.5 mm.

[0023] When using the above technical solution, when L5 is greater than or equal to 50μm, the width of the first passivation contact structure between the second hollow region adjacent to the first hollow region and the first hollow region along the second direction is greater than or equal to 50μm. The width of the first passivation contact structure reserves sufficient space for the first sub-bus electrode subsequently formed at a corresponding position above it, ensuring that the width of the first sub-bus electrode corresponding to the first passivation contact structure meets actual needs. Furthermore, if the width of the first passivation contact structure between the second hollow region adjacent to the first hollow region and the first hollow region along the second direction is less than 50μm, the first conductive contact layer cannot effectively collect current and is easily removed during the cleaning process. When L5 is less than or equal to 1.5mm, along the second direction, the width of the first passivation contact structure between the second hollow area adjacent to the first hollow area and the first hollow area is less than or equal to 1.5mm. By controlling the size of the first passivation contact structure at this position, the parasitic absorption of light by the first passivation contact structure is reduced, the light absorption loss in the power generation area of ​​the battery cell is reduced, the light energy loss is reduced, the effective utilization rate of the incident light is significantly improved, and more photons are transmitted to the semiconductor substrate, so that more photons can participate in the photoelectric conversion process, thereby improving the photoelectric conversion efficiency of solar cells.

[0024] In one implementation, a distance between two adjacent first hollow regions along the first direction is L6, which satisfies 50 μm≤L6≤1 mm.

[0025] When using the above technical solution, when L6 is greater than or equal to 50μm, the width of the first passivation contact structure between two adjacent first hollow regions is greater than or equal to 50μm. This width of the first passivation contact structure reserves sufficient space for the first collector electrode subsequently formed at the corresponding position above it, ensuring that the width of the first collector electrode corresponding to the first passivation contact structure meets actual needs. When L6 is less than or equal to 1mm, the width of the first passivation contact structure between two adjacent first hollow regions is less than or equal to 1mm. By controlling the size of the first passivation contact structure at this position, the parasitic absorption of light by the first passivation contact structure is reduced, the utilization rate of light is improved, and thus the photoelectric conversion efficiency of the solar cell is improved.

[0026] In one implementation, a portion of the first collecting electrode adjacent to the first edge is disconnected at the first end bus electrode region, and a first passivation contact structure corresponding to the first collecting electrode penetrates the first end bus electrode region along an extension direction of the first collecting electrode.

[0027] When the above technical solution is adopted, the impact of welding of conductive connectors such as welding strips on the first collector electrode in the first end busbar region can be reduced, thereby minimizing or avoiding the number of first collector electrodes damaged. In particular, the first collector electrode located in the first end busbar region and in the partial area adjacent to the first edge is subjected to greater pressure from the conductive connectors such as welding strips after connection, making it more likely to be damaged by welding or even destroy the first passivated contact structure there. Therefore, in the present application, the portion of the first collector electrode adjacent to the first edge is disconnected in the first end busbar region.

[0028] Furthermore, since part of the first collecting electrode adjacent to the first edge is disconnected at the first end bus electrode region, there is an area without the first collecting electrode in the first end bus electrode region and in part of the area adjacent to the first edge, that is, a blank area. In the subsequent process of manufacturing photovoltaic modules, the bent portion of the conductive connector such as the welding ribbon is connected to other solar cells using this blank area, which can reduce or avoid the occurrence of hidden cracks or fragments of the solar cell due to the elevation of the first collecting electrode, and reduce the height difference between the conductive connector to be welded to the first side of the first solar cell and the conductive connector to be welded to the second side of the second solar cell, so as to improve the yield of the cell string and the solar module. In addition, the first passivation contact structure corresponding to the first collecting electrode passes through the first end bus electrode region along the extension direction of the first collecting electrode, which on the one hand improves the mechanical strength of the edge of the solar cell, and on the other hand provides a transmission channel for carriers. The carriers can be collected and transmitted through the first passivation contact structure that passes through, thereby improving the short-circuit current and battery efficiency.

[0029] In one implementation, a size of the first hollow region closest to the first end pad is smaller than a size of the first hollow region farther from the first end pad.

[0030] In one implementation, the first hollow region closest to the first end pad is closer to the first collecting electrode in the first end bus electrode region than the first end pad.

[0031] The above technical solution reduces or prevents the probability of removal of the first passivation contact structure beneath the first end pad when forming the first hollowed-out region closest to the first end pad, thereby reducing or preventing direct contact between the first end pad and the underlying semiconductor substrate. This reduces or prevents the formation of recombination centers, improving minority carrier lifetime and battery open-circuit voltage, while also reducing contact resistance and improving current collection efficiency.

[0032] In one implementation, the solar cell further includes: connecting pads. A plurality of connecting pads are spaced apart on the first bus electrode connecting line along the first direction, and a length of a second hollow region circumferentially located on the connecting pads along the second direction is less than a length of a second hollow region away from the connecting pads along the second direction.

[0033] The above technical solution reduces or prevents the probability of removal of the corresponding first passivation contact structure beneath the connection pad when forming the second hollowed-out region circumferentially around the connection pad, thereby reducing or preventing direct contact between the connection pad and the underlying semiconductor substrate. This reduces or prevents the formation of recombination centers, improving minority carrier lifetime and battery open-circuit voltage, while also reducing contact resistance and improving current collection efficiency.

[0034] In one implementation, the distance between the first hollow region and the first sub-bus electrode is greater than the distance between the first hollow region and the first collecting electrode.

[0035] When adopting the above technical solution, the function of the first collecting electrode is to collect carriers. The closer the first hollow area is to the first collecting electrode, the more carriers are produced around the first collecting electrode due to the reduction of parasitic absorption of light, and the more carriers are collected, which is beneficial to increase the number of carriers; the first sub-collecting electrode is used to collect and transmit the current on the first collecting electrode, and it itself is not responsible for collecting carriers. Maintaining a larger safety distance can improve the reliability of solar energy and be compatible with process errors.

[0036] In one implementation, the distance between the first hollow area and the first sub-bus electrode is greater than or equal to 50 μm and less than or equal to 1.5 mm.

[0037] When using the above technical solution, the first sub-bus electrode is used to collect and transmit current from the first collecting electrode, and it is not responsible for collecting carriers itself. When the distance between the first hollowed-out area and the first sub-bus electrode is within the above range, a larger safe distance is maintained between the first hollowed-out area and the first sub-bus electrode, thereby improving the reliability of solar energy and compatibility with process errors.

[0038] In one implementation, the distance between the first hollow region and the first collecting electrode is greater than or equal to 50 μm and less than or equal to 1 mm.

[0039] When adopting the above technical solution, the function of the first collecting electrode is to collect carriers. The closer the first hollow area is to the first collecting electrode, the more carriers are produced around the first collecting electrode due to the reduction of parasitic absorption of light, and the more carriers are collected, which is beneficial to increase the number of carriers. Therefore, in this application, the distance between the first hollow area and the first collecting electrode is set to be greater than or equal to 50μm and less than or equal to 1mm.

[0040] In one implementation, for the same first end bus electrode, along the direction approaching the first end pad, the spacing between the two outermost first sub-bus electrodes decreases, the length of the first hollow area between the two adjacent first sub-bus electrodes decreases, and the length direction of the first hollow area is consistent with the second direction.

[0041] When adopting the above technical solution, on the basis of ensuring that the first sub-bus electrode and the first collecting electrode have the first passivation contact structure at the corresponding positions below, the area of ​​the first hollow region is made larger to reduce the parasitic absorption of light by the first passivation contact structure, reduce the light absorption loss in the power generation area of ​​the battery cell, reduce the light energy loss, significantly improve the effective utilization rate of the incident light, enable more photons to be transmitted to the semiconductor substrate, so that more photons can participate in the photoelectric conversion process, and improve the photoelectric conversion efficiency of solar cells.

[0042] In one implementation, for the same first end bus electrode, any two adjacent first sub-bus electrodes are parallel to each other; along the first direction, the length of the first hollow area between the two adjacent first sub-bus electrodes remains unchanged, and the length direction of the first hollow area is consistent with the second direction.

[0043] In one implementation, the second hollow region includes a plurality of second sub-hollow regions, the plurality of second sub-hollow regions being spaced apart along the second direction, and / or the plurality of second sub-hollow regions being abutted along the second direction.

[0044] When the above technical solution is adopted, in the process of actually forming the second hollow area, the first passivation contact structure is processed by laser, and the laser spot formed in the laser processing process is arranged along the second direction. When two adjacent laser spots are superimposed or abutted, the two adjacent second sub-hollow areas are superimposed or abutted along the second direction. When two adjacent laser spots are spaced apart, the two adjacent second sub-hollow areas are spaced apart along the second direction. It can be seen that the method of forming the second hollow area can be selected according to actual needs, which increases the application scenarios of solar cells and expands the scope of application of solar cells. Furthermore, when multiple second sub-hollow areas are spaced apart along the second direction, there is a first passivation contact structure between the two adjacent second sub-hollow areas. The above-mentioned first passivation contact structure is conducive to the transmission of carriers. The carriers are transmitted to the first collector electrode through the first passivation contact structure to improve the current collection capacity of the solar cell.

[0045] In one implementation, the first surface of the semiconductor substrate includes a first region and a second region surrounding the first region; the first bus electrode and the first collector electrode are located in the first region; and the first passivation contact structure is located in both the first region and the second region.

[0046] When the above technical solution is adopted, it can be seen from the above that the second region is located between the multiple edges of the semiconductor substrate and the first region. Because the first passivation contact structure is formed in the second region surrounding the first region, compared to a case where the first passivation contact structure is not formed in the second region surrounding the first region, the present application can improve the mechanical strength of the second region of the solar cell (i.e., the region near the edge of the solar cell) and reduce the fragmentation rate of the second region of the solar cell.

[0047] In one implementation, the first passivation contact structure further has a third hollow region, and the third hollow region is located in the second region and close to the first edge.

[0048] When the above technical solution is adopted, the parasitic absorption of light by the first passivation contact structure can be further reduced, the utilization rate of light can be improved, and the photoelectric conversion efficiency of the solar cell can be improved.

[0049] In one implementation, the first end bus electrode includes three first sub-bus electrodes extending along the first direction and spaced apart along the second direction; the area between two adjacent first sub-bus electrodes constitutes a first sub-end bus electrode area; and each first sub-end bus electrode area has a first hollow area.

[0050] When the above technical solution is adopted, compared with the prior art where there is no first sub-bus electrode and only a first bus electrode connecting line, the number of first sub-bus electrodes in this application is increased, and the area where each first sub-bus electrode collects carriers is reduced. At this time, the first sub-bus electrode can improve its ability to collect carriers generated in this area, improve the first sub-bus electrode's ability to collect current, and at the same time make the current collection more uniform. Furthermore, in the process of forming a photovoltaic module, when a conductive connector such as a welding ribbon is simultaneously connected to the first end pad and the first sub-bus electrode located in the middle of the first end bus electrode, compared with the case where the conductive connector such as the welding ribbon is only connected to the first end pad, this application not only improves the speed of current transmission to the conductive connector such as the welding ribbon, and the current collection ability of the conductive connector such as the welding ribbon, and reduces current transmission loss; it also improves the connection strength of the conductive connector such as the welding ribbon, thereby improving the yield rate of the solar cell.

[0051] In one implementation, the solar cell further includes: a second passivation contact structure formed on the second surface of the semiconductor substrate; A second bus electrode is formed above the second passivation contact structure; a plurality of second bus electrodes extend along the first direction and are spaced apart along the second direction; The second bus electrode includes: a second bus electrode connecting line, a third end pad disposed in the second bus electrode connecting line close to the first edge along the first direction, and a third end bus electrode connected to the third end pad; The third end bus electrode includes at least two third sub-bus electrodes extending along the first direction and spaced apart along the second direction; the area between the two outermost third sub-bus electrodes constitutes the third end bus electrode area; A second collecting electrode is formed above the second passivation contact structure; a plurality of second collecting electrodes extend along the second direction and are spaced apart along the first direction; and the second bus electrode intersects with the plurality of second collecting electrodes; The second passivation contact structure has a fourth hollow region and a fifth hollow region; the fourth hollow region is located within the third end bus electrode region; the fifth hollow region is located outside the third end bus electrode region and between the second collecting electrodes.

[0052] Using the above-mentioned technical solution, the present application achieves dual optimization of optical and electrical performance by introducing a fourth hollow region within the third-end busbar region. This design significantly improves the effective utilization of incident light by reducing light absorption losses in the cell's power generation area, allowing more photons to participate in the photoelectric conversion process. More importantly, the inclusion of the fourth hollow region within the third-end busbar region addresses the current collection mismatch problem present in prior art, which involves low efficiency in collecting photogenerated carriers in certain regions due to uneven electric field distribution within the cell. By matching the fourth hollow region within the third-end busbar region with the fifth hollow region outside the third-end busbar region, the effective carrier collection efficiency in the electrode region is significantly improved while also effectively suppressing non-radiative recombination losses. This improves key performance parameters such as fill factor (FF) and open-circuit voltage (Voc) while simultaneously increasing short-circuit current (Jsc), ultimately significantly enhancing the overall conversion efficiency of the solar cell. In addition, under the joint action of the first hollow region and the second hollow region of the first passivation contact structure and the fourth hollow region and the fifth hollow region of the second passivation contact structure, the bifaciality of the solar cell is improved.

[0053] In a second aspect, the present invention further provides a photovoltaic module. The photovoltaic module includes a cell string and an encapsulation layer. The cell string includes a plurality of conductive connectors and a plurality of solar cells according to the above technical solution. The conductive connectors connect the plurality of solar cells in series. The encapsulation layer is used to cover the surface of the cell string.

[0054] The beneficial effects of the photovoltaic module provided by the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 Schematic diagram of a partial structure of a solar cell when the first end bus electrode includes two first sub-bus electrodes in an embodiment of the present invention Figure 1 ; Figure 2 Schematic diagram of a partial structure of a solar cell when the first end bus electrode includes two first sub-bus electrodes in an embodiment of the present invention Figure 2 ; Figure 3 is a schematic diagram of a partial structure of a solar cell when the first end bus electrode includes three first sub-bus electrodes in an embodiment of the present invention; Figure 4Schematic diagram of the structure after the conductive connector and two solar cells are connected in an embodiment of the present invention.

[0056] Reference numerals: 10-first edge, 11-first area, 12-second area, 13-third edge; 2-first passivation contact structure, 20-first hollow area, 21-second hollow area, 22-third sub-hollow area, 23-second sub-hollow area, 24-third hollow area, 25-sixth hollow area; 3-first bus electrode, 30-first bus electrode connecting line, 31-first end pad, 320-first sub-bus electrode; 4-first collecting electrode; 5-conductive connecting member, 50-first connecting section, 51-second connecting section, 52-third connecting section, 53-first end section, 54-second end section, 55-third end section, 56-fourth end section; 6-first solar cell, 7-second solar cell. DETAILED DESCRIPTION

[0057] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0058] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0060] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0061] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and may encompass internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0062] In order to solve the above technical problems, in the first aspect, the present invention provides a solar cell. Figures 1 to 3 The solar cell includes a semiconductor substrate, a first passivation contact structure 2, a first bus electrode 3, and a first collecting electrode 4. The semiconductor substrate includes opposing first and second surfaces; along a first direction A, the semiconductor substrate includes opposing first edges 10 and second edges; the first passivation contact structure 2 is formed on the first surface of the semiconductor substrate; the first collecting electrode 4 is formed above the first passivation contact structure 2; a plurality of first collecting electrodes 4 extend along a second direction B and are spaced apart along the first direction A. The first bus electrode 3 is formed above the first passivation contact structure 2; the first bus electrode 3 intersects the plurality of first collecting electrodes 4. At least a portion of the first bus electrode 3 includes a first end pad 31 proximate to the first edge 10 and a first end bus electrode connected to the first end pad 31, the first end bus electrode being located between the first end pad 31 and the first edge 10. The first end bus electrode includes at least two first sub-bus electrodes 320; the area between the two outermost first sub-bus electrodes 320 constitutes the first end bus electrode area. The first passivation contact structure 2 includes a first hollow region 20 and a second hollow region 21; the first hollow region 20 is located within the first end bus electrode region; the second hollow region 21 is located outside the first end bus electrode region and between the first collecting electrodes 4. It should be noted that along the thickness direction of the solar cell, all areas encompassed by the projection of the area between the two outermost first sub-bus electrodes 320 onto the semiconductor substrate are considered first end bus electrode regions. For example, in the first passivation contact structure, along the thickness direction of the solar cell, the area encompassed by the projection of the area between the two outermost first sub-bus electrodes 320 onto the semiconductor substrate is also referred to as the first end bus electrode region.

[0063] See also Figures 1 to 3In the solar cell provided by an embodiment of the present invention, the first bus electrode 3 is formed above the first passivation contact structure 2 and does not directly contact the semiconductor substrate. This reduces metal recombination in the solar cell, increases the open-circuit voltage of the solar cell, and thereby improves the cell efficiency of the solar cell. Furthermore, since the first collector electrode 4 is formed above the first passivation contact structure 2 and is electrically connected to the first passivation contact structure 2, this not only ensures good ohmic contact, but also reduces contact resistivity and series resistance, effectively collecting current, reducing electrical losses, and improving the cell efficiency of the solar cell. It also reduces the carrier transmission distance, thereby reducing carrier recombination losses during transmission. Furthermore, the first passivation contact structure 2 has a first hollow region 20 and a second hollow region 21. The first hollow region 20 is located within the first end bus electrode region; the second hollow region 21 is located outside the first end bus electrode region and between the first collector electrode 4. That is, both the first hollow region 20 and the second hollow region 21 are located in the non-metallic paste region of the solar cell. This application achieves dual optimization of optical and electrical performance by introducing a first hollow region 20 within the first end busbar region. This design significantly improves the effective utilization of incident light by reducing light absorption losses in the cell's power generation area, allowing more photons to participate in the photoelectric conversion process. More importantly, the inclusion of the first hollow region 20 within the first end busbar region addresses the current collection mismatch problem present in prior art, which involves low efficiency in collecting photogenerated carriers in certain regions due to uneven electric field distribution within the cell. By aligning the first hollow region 20 within the first end busbar region with the second hollow region 21 outside the first end busbar region, the effective carrier collection efficiency in the electrode region is significantly improved while also effectively suppressing non-radiative recombination losses. This improves key performance parameters such as fill factor (FF) and open-circuit voltage (Voc) while simultaneously increasing short-circuit current (Jsc), ultimately significantly enhancing the overall conversion efficiency of the solar cell.

[0064] As a possible implementation, the first direction and the second direction can be any two directions parallel to the surface of the semiconductor substrate and different from each other. Figures 1 to 3 , the first direction A and the second direction B are orthogonal.

[0065] As a possible implementation manner, the first surface is the backlight surface of the solar cell, and the second surface is the light-receiving surface of the solar cell.

[0066] As a possible implementation, the solar cell may be a TOPCon cell.

[0067] In actual application, the specific structure of the aforementioned solar cell can be determined according to the actual application scenario, and is not specifically limited here. For example: the above-mentioned semiconductor substrate can be only a semiconductor substrate. Exemplarily, the above-mentioned semiconductor substrate can be a silicon substrate. In terms of conductivity type, the semiconductor substrate can be an N-type conductive substrate or a P-type conductive substrate. Preferably, the semiconductor substrate is an N-type conductive substrate. N-type conductive substrates have significant advantages over traditional P-type conductive substrates, which are mainly reflected in longer carrier lifetime, improved efficiency, attenuation control and long-term reliability, etc., which are beneficial to reducing the series resistance of solar cells and improving the efficiency of solar cells. From a structural point of view, the first surface of the semiconductor substrate can be a velvet surface to improve the light trapping effect of the solar cell to the light surface, thereby improving the utilization rate of light by the solar cell. Of course, the first surface of the semiconductor substrate can also be a polished surface. As for the second surface of the semiconductor substrate, it can be a polished surface or a velvet surface, and is not specifically limited here.

[0068] In one implementation, see Figures 1 to 3 At least part of the first bus electrode 3 further includes: a first bus electrode connecting line 30, a plurality of first bus electrode connecting lines 30 extending along the first direction A and spaced apart along the second direction B; a first end pad 31 is arranged at one end of the first bus electrode connecting line 30 close to the first edge 10.

[0069] See also Figures 1 to 3 In the solar cell metallization process, burn-through pastes penetrate the passivation layer through high-temperature sintering, resulting in low contact resistance but potentially damaging the passivation layer. Non-burn-through pastes, on the other hand, require laser grooving, leaving the passivation layer intact and reducing recombination losses. The paste used to form the first collector electrode 4 is a burn-through paste. Alternatively, a non-burn-through paste can be used for the first collector electrode 4, enabling ultra-fine first collector electrodes (<20μm) and reducing shading. For the first busbar electrode 3, burn-through pastes are suitable for high current transmission, while non-burn-through pastes are suitable for multi-busbar (MBB) and low-temperature processes. As one possible implementation, the pastes used to form the first busbar electrode connection line 30, the first end pad 31, and the first end busbar electrode are all non-burn-through pastes. The specific paste materials used for these three can be the same or different. In some embodiments, the pastes used to form the first busbar electrode connection line 30, the first end pad 31, and the first end busbar electrode are made of the same material, allowing them to be printed simultaneously, simplifying the process and reducing costs.

[0070] As a possible implementation, see Figures 1 to 3The first passivation contact structure 2 can be composed of a P-type doped conductive semiconductor layer and a tunneling layer, or it can be composed of an N-type doped conductive semiconductor layer and a tunneling layer. The tunneling layer can produce a tunneling effect. More specifically, the tunneling layer can act as a barrier between electrons and holes. That is, the tunneling layer can prevent minority carriers from being transmitted. After minority carriers accumulate in the portion adjacent to the tunneling layer, only majority carriers with energies of a certain level or higher can pass through the tunneling layer. Majority carriers with energies of a certain level or higher can easily pass through the tunneling layer. In addition, the tunneling layer can also serve as a diffusion barrier to prevent dopants from the N-type doped conductive semiconductor layer or the P-type doped conductive semiconductor layer from diffusing into the semiconductor substrate. The tunneling layer can be composed of various materials through which majority carriers can tunnel. For example, the tunneling layer can be composed of oxides, nitrides, semiconductors, and conductive polymers.

[0071] Specifically, the tunneling layer may be formed of a silicon oxide layer including silicon oxide (SiOx), because the silicon oxide layer has excellent passivation characteristics and carriers can easily tunnel through the silicon oxide layer.

[0072] In some embodiments, the tunneling layer can be made of a dielectric material including SiCx, which has strong durability even under high-temperature processing, or can be made of SiNx, hydrogenated SiNx, AlOx, SiON, or hydrogenated SiON. The tunneling layer is formed on a semiconductor substrate, and an N-type doped conductive semiconductor layer or a P-type doped conductive semiconductor layer is formed on the tunneling layer. The N-type doped conductive semiconductor layer or the P-type doped conductive semiconductor layer is formed by doping impurities of different conductivity types into an amorphous silicon material, a microcrystalline silicon material, or a polycrystalline silicon material. This structure not only effectively passivates dangling bonds on the silicon surface, but also provides an electric field, allowing majority carriers to form current through the electric field and preventing minority carriers from migrating to the surface and recombination. In addition, the metal-semiconductor contact of this structure has low metal recombination, thereby improving the passivation effect of the solar cell. Furthermore, the improved passivation effect can significantly increase the open-circuit voltage of the solar cell, thereby improving the cell efficiency.

[0073] Combined with the above description, see Figures 1 to 3 When the first passivation contact structure 2 includes the first hollow region 20 and the second hollow region 21, portions of the doped conductive semiconductor layer and the corresponding tunneling layer are removed. This reduces the doped conductive semiconductor layer's absorption of near-infrared light, lowering light energy loss and allowing more photons to reach the semiconductor substrate. This improves photoelectric conversion efficiency, increases bifaciality, and enhances the solar cell's power generation capacity. Furthermore, removing portions of the doped conductive semiconductor layer reduces doping recombination effects, increases carrier lifetime, and optimizes the open-circuit voltage (Voc).

[0074] See also Figures 1 to 3 Regarding metal recombination losses, the contact between the metal and semiconductor is not a simple metal-semiconductor connection, but rather a metal-semiconductor alloy. During the alloying process, in addition to the alloy, some scattered metal powder will be free in the semiconductor. This metal in the semiconductor is a deep-level impurity and does not participate in conduction. At the same time, it will act as a recombination center, trapping electrons transmitted from the valence band to the conduction band, causing very serious metal recombination. Because the first passivation contact structure 2 has a high doping concentration and can form alloys with a large amount of metal, the free metal particles produced are relatively small. At the same time, because the first passivation contact structure 2 has a doped conductive semiconductor layer and a tunneling layer, the metal generally does not pass through the tunneling layer to contact the semiconductor substrate, thereby reducing metal recombination.

[0075] See also Figures 1 to 3 For ease of description, the first passivation contact structure 2 directly below the first bus electrode 3 is defined below as the first sub-passivation contact structure, and the first passivation contact structure 2 directly below the first collector electrode 4 is defined below as the second sub-passivation contact structure. In addition to passivating the surface, the first sub-passivation contact structure also collects the current collected by the first collector electrode 4. Since the metal used in the solar cell embodiments of the present invention is generally a metal paste, the metal material used is often metal powder. This metal powder has a certain particle size and is therefore susceptible to downward corrosion when forming a metal-semiconductor alloy. Therefore, the first sub-passivation contact structure needs to have a certain thickness to prevent the metal from burning through the first sub-passivation contact structure and coming into direct contact with the semiconductor substrate. Therefore, the first sub-passivation contact structure needs to have a certain thickness to act as a barrier to reduce metal recombination. Furthermore, the primary function of the first sub-passivation contact structure, excluding the first sub-passivation contact structure directly below the first bus electrode 3, is to assist the second sub-passivation contact structure in collecting current, reducing the carrier transmission distance and thereby reducing recombination losses. However, since the parasitic absorption of the first sub-passivation contact structure is strong (that is, when light passes through the first sub-passivation contact structure, most of the light energy is absorbed by the first sub-passivation contact structure, and no large number of photogenerated carriers are generated at the PN junction, the ineffective absorption is large, resulting in current loss), the thicker the first sub-passivation contact structure, the lower the current.

[0076] See also Figures 1 to 3For the entire solar cell, the first passivation contact structure 2 cannot block an area that is too large, as this will reduce the absorption of light by the entire solar cell and reduce the generation of photogenerated carriers. However, the photogenerated carriers generated by the entire solar cell need to be collected. Therefore, considering the photogenerated carrier collection efficiency, the first passivation contact structure 2 should cover the entire surface as much as possible. However, the disadvantages of the first passivation contact structure 2 blocking light must be taken into account and the entire surface cannot be completely blocked. After comprehensive consideration, a first hollow area 20 and a second hollow area 21 are provided on the first passivation contact structure 2, so that the remaining first passivation contact structures 2 are connected into a network, which not only avoids excessive blocking but also ensures current collection. At the same time, the good passivation effect of the first passivation contact structure 2 improves the passivation effect of the entire solar cell. However, if the area of ​​the first passivation contact structure 2 is too small, the current collection path will become longer, the series connection will become larger, and the recombination loss will increase. The higher doping concentration of the first passivation contact structure 2 is conducive to forming a good metal-semiconductor contact, and the lower doping concentration is conducive to reducing recombination. Therefore, it is necessary to comprehensively consider the area ratio and doping concentration of the first passivation contact structure 2 , so as to take into account the open circuit voltage, short circuit current and fill factor of the solar cell, so as to form a cell structure of a solar cell with higher efficiency.

[0077] As a possible implementation, see Figure 2 The first hollow area 20 and the second hollow area 21 have equal widths in the first direction A; the first hollow area 20 has a first center line O extending along the second direction B; along the second direction B, the second hollow area 21 adjacent to the first hollow area 20 has a second center line P extending along the second direction B.

[0078] The relative positional relationship between the first center line and the second center line can be: Example 1: See Figure 2 , the first center line O and the second center line P are collinear.

[0079] See also Figure 2 , since the first collector electrode 4 is made of a burn-through paste, the burn-through paste easily allows the metal to reach the semiconductor substrate, causing increased metal recombination, etc. In order to avoid the above situation, in the present application, the first center line O and the second center line P are collinear, and at this time, a safe distance can be ensured between the first hollow area 20 and the second hollow area 21 and the first collector electrode 4 located on both sides of the first hollow area 20 and the second hollow area 21, avoiding the first hollow area 20 and the second hollow area 21 from being too close to the first collector electrode 4, so as to avoid the generation of carrier recombination centers and metal recombination, thereby increasing the open circuit voltage of the solar cell, improving the short circuit current and fill factor of the solar cell, reducing the contact resistance, and thus improving the cell efficiency of the solar cell.

[0080] Example 2: See Figure 2 , along the first direction A, a ratio of the distance between the first center line O and the second center line P to the width of the first hollow area 20 along the first direction A or to the width of the second hollow area 21 along the first direction A is less than or equal to 10%. For example, the ratio may be 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%.

[0081] Example 3: See Figure 2 When the first passivation contact structure 2 has multiple first hollow areas 20 and multiple second hollow areas 21, the first center line O and the second center line P are collinear at the same time; and along the first direction A, the ratio of the distance between the first center line O and the second center line P to the width of the first hollow area 20 along the first direction A or to the width of the second hollow area 21 along the first direction A is less than or equal to 10%.

[0082] See also Figure 2 The first hollow region 20 and the second hollow region 21 are formed after laser processing of the first passivation contact structure 2. If the above ratio is greater than 10%, it indicates that during the laser processing of the first passivation contact structure 2, the first hollow region 20 is offset too much relative to the second hollow region 21 in the first direction A, or the second hollow region 21 is offset too much relative to the first hollow region 20 in the first direction A. In this case, it is very likely that the first hollow region 20 or the second hollow region 21 is located below the first collector electrode 4, resulting in the interruption of the first passivation contact structure 2 below the first collector electrode 4. In other words, the laser can easily remove the portion of the first passivation contact structure 2 below the first collector electrode 4, causing the first collector electrode 4 to be directly welded to the semiconductor substrate when the first collector electrode 4 is subsequently formed, resulting in carrier recombination centers and metal recombination, reducing the short-circuit current and fill factor of the solar cell and increasing the contact resistance. In summary, when the ratio of the distance between the first center line O and the second center line P to the width of the first hollow area 20 along the first direction A or to the width of the second hollow area 21 along the first direction A is less than or equal to 10%, the first collecting electrode 4 can be prevented from being directly welded to the semiconductor substrate, thereby avoiding the generation of carrier recombination centers and metal recombination, thereby increasing the open circuit voltage of the solar cell, improving the short circuit current and fill factor of the solar cell, reducing the contact resistance, and thereby improving the cell efficiency of the solar cell.

[0083] As a possible implementation, see Figure 2 The first end bus electrode region has a plurality of first hollow regions 20 spaced apart along the first direction A.

[0084] See also Figure 2At this point, not only can the first passivation contact structure 2 effectively reduce the shielding of the semiconductor substrate, but also reduce the parasitic absorption of light by the first passivation contact structure 2, reduce light absorption loss in the power generation area of ​​the cell, and reduce light energy loss, but it can also significantly improve the effective utilization rate of the incident light, allowing more photons to be transmitted to the semiconductor substrate, thereby allowing more photons to participate in the photoelectric conversion process, and improving the photoelectric conversion efficiency of the solar cell. At the same time, it can also increase the carrier generation rate in the first end bus electrode region, reduce the recombination rate, and reduce the current collection mismatch. In addition, it further solves the current collection mismatch problem existing in the prior art.

[0085] In some embodiments, see Figure 2 , two adjacent first hollow areas 20 are staggered in the first direction A.

[0086] See also Figure 2 When the above technical solution is adopted, when the first hollow area 20 is opened on the first passivation contact structure 2, the first hollow area 20 will destroy the original stress distribution, and stress concentration is likely to occur at the edge of the first hollow area 20. When two adjacent first hollow areas 20 are staggered in the first direction A, the stress can be dispersed in different directions, avoiding the overlap of stress concentration areas and reducing the risk of local fracture. Furthermore, when the first collecting electrode 4 and the first bus electrode 3 are subsequently manufactured on the first passivation contact structure 2 with the first hollow area 20, the probability of the first passivation contact structure 2 corresponding to the first collecting electrode 4 and the first bus electrode 3 being fractured due to stress concentration can be reduced, thereby reducing or avoiding the generation of carrier recombination centers and metal recombination, thereby increasing the open circuit voltage of the solar cell, improving the short circuit current and fill factor of the solar cell, and thereby improving the cell efficiency of the solar cell. In addition, the two adjacent first hollow areas 20 are staggered in the first direction A, which can disperse the processing errors and avoid the cumulative errors during processing that cause the position deviations of all the first hollow areas 20 to be superimposed along the first direction A, thereby avoiding the processing errors from exceeding the design errors, improving the fault tolerance rate, and thus improving the quality of the solar cell.

[0087] As a possible implementation, see Figure 2 The distance between the two second hollow areas 21 on both sides of the first end pad 31 along the second direction B is L1, and the distance between the two second hollow areas 21 on both sides of the first bus electrode connection line 30 along the second direction B is L2, satisfying that L1 is greater than L2.

[0088] See also Figure 2Using this technical solution, the removal of the first passivation contact structure 2 below the first end pad 31 during the formation of the two second hollowed-out regions 21 located on either side of the first end pad 31 along the second direction B can be reduced or avoided, thereby reducing or preventing direct contact between the first end pad 31 and the underlying semiconductor substrate. This reduces or prevents the formation of recombination centers, thereby improving minority carrier lifetime and cell open-circuit voltage. It also reduces contact resistance and improves current collection efficiency.

[0089] As a possible implementation, see Figure 2 , along the second direction B, the distances between the two second hollow regions 21 located on both sides of the first bus electrode connecting line 30 and the first bus electrode connecting line 30 are not equal.

[0090] See also Figure 2 When the photovoltaic module is subsequently formed, the conductive connecting parts 5 such as welding strips are welded to the first bus electrode 3 connecting wires. Since in this application, the distances between the two second hollow areas 21 located on both sides of the first bus electrode connecting wire 30 and the first bus electrode connecting wire 30 are not equal along the second direction B, stress concentration can be reduced at this time, and the mechanical strength of the conductive connecting parts 5 such as welding strips can be improved.

[0091] Exemplarily, the two distances between the two second hollow regions 21 located on both sides of the first bus electrode connecting line 30 and the first bus electrode connecting line 30 are L3 and L4 respectively, and L3 and L4 are not equal.

[0092] As a possible implementation, see Figure 1 Along the second direction B, the distance between the first hollow area 20 and the adjacent second hollow area 21 is L5, and the distance between two adjacent first hollow areas 20 along the first direction A is L6, satisfying that L5 is greater than L6.

[0093] See also Figure 1When employing the above technical solution, the first sub-bus electrode 320 corresponds to the first passivation contact structure 2 between the second hollow region 21 adjacent to the first hollow region 20 and the first hollow region 20, and the first collecting electrode 4 corresponds to the first passivation contact structure 2 between two adjacent first hollow regions 20. Because the first bus electrode has lower contact performance with the solar cell than the first collecting electrode 4; or because the first bus electrode needs to be welded to a conductive connector 5 such as a soldering ribbon, the width of the first bus electrode is typically increased to increase the contact area with the solar cell surface or the conductive connector 5, thereby improving the contact and welding performance of the first bus electrode. Furthermore, because the first bus electrode includes the first sub-bus electrode 320, the width of the first sub-bus electrode 320 is relatively wide. Therefore, in this application, L5 is greater than L6. Furthermore, because the slurry forming the first bus electrode has high ductility, the width of the first bus electrode is greater than the width of the first collecting electrode 4, that is, the width of the first sub-bus electrode 320 is greater than the width of the first collecting electrode 4. Based on this, in this application, L5 is greater than L6 to improve the tolerance of printing deviation of the first sub-bus electrode 320. In addition, the above solution can also reduce the parasitic absorption of light by the first passivation contact structure 2 between two adjacent first hollow areas 20, thereby improving light utilization.

[0094] In an alternative approach, see Figure 1 Along the second direction B, a distance L5 between the first hollow area 20 and the adjacent second hollow area 21 is greater than or equal to 50 μm and less than or equal to 1.5 mm. For example, the distance may be 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, or 1500 μm.

[0095] When employing the above technical solution, when L5 is greater than or equal to 50 μm, the width of the first passivation contact structure 2 between the second hollow region 21 adjacent to the first hollow region 20 and the first hollow region 20 along the second direction B is greater than or equal to 50 μm. The width of the first passivation contact structure 2 reserves sufficient space for the first sub-bus electrode 320 subsequently formed at a corresponding position above it, ensuring that the width of the first sub-bus electrode 320 corresponding to the first passivation contact structure 2 above the first passivation contact structure 2 meets actual requirements. Furthermore, if the width of the first passivation contact structure 2 between the second hollow region 21 adjacent to the first hollow region 20 and the first hollow region 20 along the second direction B is less than 50 μm, the first conductive contact layer cannot effectively collect current and is easily removed during the cleaning process. When L5 is less than or equal to 1.5 mm, along the second direction B, the width of the first passivation contact structure 2 between the second hollow area 21 adjacent to the first hollow area 20 and the first hollow area 20 is less than or equal to 1.5 mm. By controlling the size of the first passivation contact structure 2 at this position, the parasitic absorption of light by the first passivation contact structure 2 is reduced, the light absorption loss in the power generation area of ​​the battery cell is reduced, the light energy loss is reduced, the effective utilization rate of the incident light is significantly improved, and more photons are transmitted to the semiconductor substrate, so that more photons can participate in the photoelectric conversion process, thereby improving the photoelectric conversion efficiency of the solar cell.

[0096] In an alternative approach, see Figure 1 The distance L6 between two adjacent first hollow areas 20 along the first direction A is greater than or equal to 50 μm and less than or equal to 1 mm. For example, the distance may be 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, or 1000 μm.

[0097] When using the above technical solution, when L6 is greater than or equal to 50μm, the width of the first passivation contact structure 2 between two adjacent first hollow regions 20 is greater than or equal to 50μm. The width of the first passivation contact structure 2 reserves sufficient space for the first collector electrode 4 subsequently formed at the corresponding position above it, ensuring that the width of the first collector electrode 4 corresponding to the first passivation contact structure 2 meets actual needs. When L6 is less than or equal to 1mm, the width of the first passivation contact structure 2 between two adjacent first hollow regions 20 is less than or equal to 1mm. By controlling the size of the first passivation contact structure 2 at this position, the parasitic absorption of light by the first passivation contact structure 2 is reduced, the utilization rate of light is improved, and thus the photoelectric conversion efficiency of the solar cell is improved.

[0098] As a possible implementation, see Figure 1 and Figure 3 The portion of the first collecting electrode 4 adjacent to the first edge 10 is disconnected at the first end bus electrode region, and the first passivation contact structure 2 corresponding to the first collecting electrode 4 extends through the first end bus electrode region along the extension direction of the first collecting electrode 4. In other words, the first passivation contact structure 2 extending through the first end bus electrode region along the extension direction of the first collecting electrode 4 corresponds to the first passivation contact structure 2 below the first collecting electrode 4 that is disconnected in the first end bus electrode region and does not exist.

[0099] See also Figure 1 and Figure 3 Utilizing the above-described technical solution, the first collector electrode 4 within the first end busbar region is less susceptible to the effects of welding on the conductive connector 5, such as welding ribbon, thereby minimizing or preventing damage to the first collector electrode 4. In particular, the first collector electrode 4 located within the first end busbar region and within a portion adjacent to the first edge 10 is subject to greater pressure from the conductive connector 5, such as welding ribbon, after connection, making it more susceptible to damage and even destruction of the first passivating contact structure 2 there. Therefore, in the present application, the portion of the first collector electrode 4 adjacent to the first edge 10 is disconnected within the first end busbar region.

[0100] Further, see Figure 1 and Figure 3 Since part of the first collecting electrode 4 adjacent to the first edge 10 is disconnected at the first end bus electrode area, there is an area without the first collecting electrode 4 in the first end bus electrode area and in part of the area adjacent to the first edge 10, that is, a blank area. In the subsequent process of manufacturing photovoltaic modules, the bent part of the conductive connector 5 such as the welding ribbon is connected to other solar cells using this blank area, which can reduce or avoid the occurrence of hidden cracks or fragments of the solar cell due to the elevation of the first collecting electrode 4, and reduce the height difference between the conductive connector 5 to be welded to the first side of the first solar cell and the conductive connector 5 to be welded to the second side of the second solar cell, so as to improve the yield of the cell string and the solar module. In addition, the first passivation contact structure 2 corresponding to the first collecting electrode 4 passes through the first end bus electrode area along the extension direction of the first collecting electrode 4, which on the one hand improves the mechanical strength of the solar cell edge, and on the other hand provides a transmission channel for carriers. The carriers can be collected and transmitted through the first passivation contact structure 2 that passes through, thereby improving the short-circuit current and battery efficiency.

[0101] As a possible implementation, see Figure 1 and Figure 3 , the number of first collecting electrodes 4 adjacent to the first edge 10 and disconnected at the first end bus electrode region is less than or equal to five.

[0102] When the above technical solution is adopted, see Figure 1 and Figure 3 While ensuring a certain size of blank area, it is ensured that the number of first collecting electrodes 4 included in the first end bus electrode area meets actual needs, so as to take into account the cell efficiency of the solar cell.

[0103] As a possible implementation, see Figure 2 The size of the first hollow area closest to the first end pad 31 (defined as the third sub-hollow area 22 for ease of identification) is smaller than the size of the first hollow area 20 far away from the first end pad 31.

[0104] In an alternative approach, see Figure 2 The first hollow region 20 (ie, the third sub-hollow region 22 ) closest to the first end pad 31 is closer to the first collecting electrode 4 in the first end bus electrode region than the first end pad 31 .

[0105] When the above technical solution is adopted, see Figure 2 This reduces or prevents the probability of removal of the first passivation contact structure 2 beneath the first end pad 31 during the formation of the first hollow region 20 closest to the first end pad 31, thereby reducing or preventing direct contact between the first end pad 31 and the underlying semiconductor substrate. This not only reduces or prevents the formation of recombination centers, improving minority carrier lifetime and cell open-circuit voltage, but also reduces contact resistance and improves current collection efficiency.

[0106] As another possible implementation, see Figures 1 to 3 , remove the first hollow area 20 closest to the first end pad 31 (that is, do not open the first hollow area 20 closest to the first end pad 31, in other words, do not open the attached Figure 2 The third sub-hollow region 22 in the hollow region 22 is formed to completely avoid the first passivation contact structure 2 corresponding to the first end pad 31 being removed when the first hollow region 20 closest to the first end pad 31 is formed.

[0107] As a possible implementation, see Figures 1 to 3The size of the second hollow region 21 located circumferentially to the first end pad 31 is smaller than the size of the second hollow region 21 away from the first end pad 31, and the second hollow region 21 located circumferentially to the first end pad 31 is away from the first end pad 31. That is, the small-sized second hollow region 21 located circumferentially to the first end pad 31 is opened at a position away from the first end pad 31, so as to reduce or avoid the probability of the first passivation contact structure 2 corresponding to the bottom of the first end pad 31 being removed when the second hollow region 21 located circumferentially to the first end pad 31 is formed, thereby reducing or avoiding direct contact between the first end pad 31 and the semiconductor substrate below it. At this time, not only can the generation of recombination centers be reduced or avoided, thereby improving the minority carrier lifetime and the open-circuit voltage of the battery, but also the contact resistance can be reduced and the current collection efficiency can be improved.

[0108] As another possible implementation, see Figures 1 to 3 , the second hollow area 21 located around the first end pad 31 is removed (that is, the second hollow area 21 located around the first end pad 31 is not opened) to completely avoid the first passivation contact structure 2 corresponding to the bottom of the first end pad 31 being removed when the second hollow area 21 located around the first end pad 31 is formed.

[0109] As a possible implementation, see Figures 1 to 3 The solar cell further includes: a plurality of connection pads arranged on the first bus electrode connection line 30 at intervals along the first direction A.

[0110] As a possible implementation, see Figures 1 to 3 , the length of the second hollow area 21 located in the circumference of the connecting pad along the second direction B is less than the length of the second hollow area 21 away from the connecting pad along the second direction B. In some embodiments, the second hollow area 21 located in the circumference of the connecting pad is away from the connecting pad. That is, the small-sized second hollow area 21 located in the circumference of the connecting pad is opened at a position away from the connecting pad to reduce or avoid the probability of the corresponding first passivation contact structure 2 under the connecting pad being removed when the second hollow area 21 located in the circumference of the connecting pad is formed, so as to reduce or avoid direct contact between the connecting pad and the semiconductor substrate below it. At this time, not only can the generation of recombination centers be reduced or avoided, and the minority carrier lifetime and battery open circuit voltage be improved; at the same time, the contact resistance can also be reduced and the current collection efficiency can be improved.

[0111] As another possible implementation, see Figures 1 to 3 , the second hollow area 21 located around the connecting pad is removed (that is, the second hollow area 21 located around the connecting pad is not opened) to completely avoid the first passivation contact structure 2 corresponding to the bottom of the connecting pad being removed when the second hollow area 21 located around the connecting pad is formed.

[0112] As a possible implementation, see Figure 2 , the distance between the first hollow area 20 and the first sub-bus electrode 320 is greater than the distance between the first hollow area 20 and the first collecting electrode 4. It should be noted that the distance between the first hollow area 20 and the first sub-bus electrode 320 is any distance between the first hollow area 20 and the first sub-bus electrode 320, for example, the minimum distance or the maximum distance, or the distance between the first sub-bus electrode 320 and the center line of the first hollow area 20 along the first direction A, etc.

[0113] See also Figure 2 When the above technical solution is adopted, the function of the first collecting electrode 4 is to collect carriers. The closer the first hollow area 20 is to the first collecting electrode 4, the more carriers are produced around the first collecting electrode 4 due to the reduction of parasitic absorption of light, and the more carriers are collected, which is beneficial to increase the number of carriers; the first sub-collecting electrode 320 is used to collect and transmit the current on the first collecting electrode 4, and it itself is not responsible for collecting carriers. Maintaining a larger safety distance can improve the reliability of solar energy and be compatible with process errors.

[0114] As a possible implementation, see Figure 2 The distance between the first hollow area 20 and the first sub-bus electrode 320 is greater than or equal to 50 μm and less than or equal to 1.5 mm. For example, the distance may be 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, or 1500 μm.

[0115] When the above technical solution is adopted, see Figure 2 The first sub-bus electrode 320 is used to collect and transmit current from the first collecting electrode 4 and does not collect carriers itself. When the distance between the first hollow region 20 and the first sub-bus electrode 320 is within the above range, a larger safe distance is maintained between the first hollow region 20 and the first sub-bus electrode 320 to improve the reliability of solar energy and accommodate process errors.

[0116] As a possible implementation, see Figure 2The distance between the first hollow region 20 and the first collecting electrode 4 is greater than or equal to 50 μm and less than or equal to 1 mm. For example, the distance may be 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, or 1000 μm.

[0117] When the above technical solution is adopted, see Figure 2 The function of the first collecting electrode 4 is to collect carriers. The closer the first hollow area 20 is to the first collecting electrode 4, the more carriers are produced around the first collecting electrode 4 due to the reduction of parasitic absorption of light, and the more carriers are collected, which is beneficial to increase the number of carriers. Therefore, in this application, the distance between the first hollow area 20 and the first collecting electrode 4 is set to be greater than or equal to 50μm and less than or equal to 1mm.

[0118] The shape of the first hollow area is related to the shape of the first end bus electrode area. Two possible cases are described below as examples. It should be understood that the following description is only for understanding and is not intended to be a specific limitation.

[0119] The first case: See Figures 1 to 3 For the same first end bus electrode, along the direction close to the first end pad 31, the distance between the two outermost first sub-bus electrodes 320 decreases, and the length of the first hollow area 20 between the two adjacent first sub-bus electrodes 320 decreases, and the length direction of the first hollow area 20 is consistent with the second direction B.

[0120] See also Figures 1 to 3 When the above technical solution is adopted, on the basis of ensuring that the first sub-bus electrode 320 and the first collecting electrode 4 have the first passivation contact structure 2 at the corresponding positions below, the area of ​​the first hollow region 20 is made larger to reduce the parasitic absorption of light by the first passivation contact structure 2, reduce the light absorption loss in the power generation area of ​​the battery cell, reduce the light energy loss, significantly improve the effective utilization rate of the incident light, enable more photons to be transmitted to the semiconductor substrate, so that more photons can participate in the photoelectric conversion process, and improve the photoelectric conversion efficiency of the solar cell.

[0121] For example, see Figures 1 to 3When the two outermost first sub-bus electrodes 320 extend along an oblique line (the oblique line forms an angle with respect to the first direction A) and the spacing between them decreases, the two short sides of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 also extend along the oblique line, and the spacing between the two short sides decreases, thereby reducing the length of the first hollow region 20. Alternatively, when the two outermost first sub-bus electrodes 320 extend along an oblique line and the spacing between them decreases, one short side of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 extends along the oblique line, and the other short side extends along the first direction. In this case, the spacing between the two short sides also decreases, thereby reducing the length of the first hollow region 20. Alternatively, when one of the two outermost first sub-bus electrodes 320 extends along an oblique line and the other extends along the first direction A, and the spacing between the two decreases, one short side of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 extends along an oblique line and the other short side extends along the first direction A. In this case, the spacing between the two short sides also decreases, thereby reducing the length of the first hollow region 20. Alternatively, when one of the two outermost first sub-bus electrodes 320 extends along an oblique line and the other extends along the first direction A, and the spacing between the two decreases, both short sides of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 extend along an oblique line and the spacing between the two short sides decreases, thereby reducing the length of the first hollow region 20.

[0122] The second case: See Figures 1 to 3 For the same first end bus electrode, any two adjacent first sub-bus electrodes 320 are parallel to each other; along the first direction A, the length of the first hollow area 20 located between the two adjacent first sub-bus electrodes 320 remains unchanged, and the length direction of the first hollow area 20 is consistent with the second direction B.

[0123] For example, see Figure 2For the same first end bus electrode, any two adjacent first sub-bus electrodes 320 extend along the first direction A. Along the first direction A, the two short sides of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 extend along the first direction A, so that the length of the first hollow region 20 remains unchanged. Alternatively, for the same first end bus electrode, any two adjacent first sub-bus electrodes 320 extend along an oblique line (the oblique line is at an angle to the first direction A) and are parallel to each other. Along the first direction A, the two short sides of the first hollow region 20 located between the two adjacent first sub-bus electrodes 320 also extend along an oblique line and are parallel to each other, so that the length of the first hollow region 20 remains unchanged. Furthermore, the extension direction of the two short sides of the first hollow region 20 is consistent with the extension direction of the first sub-bus electrodes.

[0124] In some embodiments, see Figure 2 For the same first end bus electrode, any two adjacent first sub-bus electrodes 320 are parallel to each other. Along the first direction A, the length of the first hollow region 20 between two adjacent first sub-bus electrodes 320 remains unchanged, and the length direction of the first hollow region 20 is consistent with the second direction B. Furthermore, at least one short side of the first hollow region 20 between two adjacent first sub-bus electrodes 320 is parallel to the first sub-bus electrode 320.

[0125] It should be noted that the first case and the second case do not limit the number of the first sub-bus electrodes 320 included in the first end bus electrode.

[0126] As a possible implementation, see Figure 4 , the second hollow area 21 includes a plurality of second sub-hollow areas 23. Along the second direction B, the plurality of second sub-hollow areas 23 are spaced apart; and / or, see Figure 1 , along the second direction B, multiple second sub-hollow areas 23 abut against each other.

[0127] When the above technical solution is adopted, see Figure 1 and Figure 4In the process of actually forming the second hollow area 21, the first passivation contact structure 2 is processed by laser. The laser spot formed during the laser processing is arranged along the second direction B. When two adjacent laser spots are superimposed or abutted, the two adjacent second sub-hollow areas 23 are superimposed or abutted along the second direction B. When two adjacent laser spots are spaced apart, the two adjacent second sub-hollow areas 23 are spaced apart along the second direction B. It can be seen that the method of forming the second hollow area 21 can be selected according to actual needs, which increases the application scenarios of solar cells and expands the scope of application of solar cells. Furthermore, when multiple second sub-hollow areas 23 are spaced apart along the second direction B, there is a first passivation contact structure 2 between the two adjacent second sub-hollow areas 23. The above-mentioned first passivation contact structure 2 is conducive to the transmission of carriers. The carriers are transmitted to the first collector electrode 4 through the first passivation contact structure 2 to improve the current collection capacity of the solar cell.

[0128] As a possible implementation, see Figure 1 The first surface of the semiconductor substrate includes a first region 11 and a second region 12 surrounding the first region 11; the first bus electrode 3 and the first collector electrode 4 are located in the first region 11; and the first passivation contact structure 2 is located in both the first region 11 and the second region 12.

[0129] As can be seen from the above, the second region 12 is located between the multiple edges of the semiconductor substrate and the first region 11. Since the first passivation contact structure 2 is formed in the second region 12 surrounding the first region 11, compared to a case where the first passivation contact structure 2 is not formed in the second region 12 surrounding the first region 11, the present application can improve the mechanical strength of the second region 12 of the solar cell (i.e., the region near the edge of the solar cell) and reduce the fragmentation rate of the second region 12 of the solar cell.

[0130] In an alternative approach, see Figure 1 The first passivation contact structure 2 further includes a third hollow region 24, which is located within the second region 12 and close to the first edge 10. This further reduces the parasitic absorption of light by the first passivation contact structure 2, thereby improving light utilization and the photoelectric conversion efficiency of the solar cell.

[0131] In an alternative approach, see Figure 1 Along the second direction B, the semiconductor substrate includes a third edge 13 and a fourth edge that are opposite each other. The first passivation contact structure 2 also includes at least one sixth hollow region 25, which is located within the second region 12 and close to the third edge 13 and / or the fourth edge. In this manner, the parasitic absorption of light by the first passivation contact structure 2 can be further reduced, thereby improving light utilization and the photoelectric conversion efficiency of the solar cell.

[0132] In some embodiments, see Figure 1 The second hollow area 21 located on one side of the sixth hollow area 25 along the second direction B is located on the same straight line as the sixth hollow area 25, and the second hollow area 21 located on one side of the sixth hollow area 25 along the second direction B is spaced apart from the sixth hollow area 25.

[0133] In other embodiments, see Figure 1 The first passivation contact structure 2 includes a plurality of sixth hollow regions 25 , wherein two adjacent sixth hollow regions 25 are spaced apart along the first direction A, and / or, two adjacent sixth hollow regions 25 abut or overlap along the first direction A.

[0134] From the above description, we can see that Figures 1 to 3 The first end bus electrode includes at least two first sub-bus electrodes 320 extending along the first direction A and spaced apart along the second direction B.

[0135] As a possible implementation, see Figure 1 The first end bus electrode includes two first sub-bus electrodes 320 extending along the first direction A and spaced apart along the second direction B.

[0136] As another possible implementation, see Figure 3 The first end bus electrode includes three first sub-bus electrodes 320 extending along the first direction A and spaced apart along the second direction B; the area between two adjacent first sub-bus electrodes 320 constitutes a first sub-end bus electrode area; each first sub-end bus electrode area has a first hollow area 20.

[0137] When the above technical solution is adopted, see Figure 3 Compared to the prior art where there is only a first bus electrode connection line 30 and no first sub-bus electrode 320, the present application increases the number of first sub-bus electrodes 320 and reduces the area in which each first sub-bus electrode 320 collects carriers. This improves the ability of the first sub-bus electrode 320 to collect carriers generated in that area, improves the current collection capability of the first sub-bus electrode 320, and also makes the current collection more uniform. Furthermore, during the process of forming a photovoltaic module, when the conductive connector 5, such as a soldering ribbon, is simultaneously connected to the first end pad 31 and the first sub-bus electrode 320 located in the middle of the first end bus electrode, compared to when the conductive connector 5, such as a soldering ribbon, is only connected to the first end pad 31, the present application not only improves the speed of current transmission to the conductive connector 5, such as a soldering ribbon, and the current collection capability of the conductive connector 5, thereby reducing current transmission losses, but also improves the connection strength of the conductive connector 5, thereby improving the yield rate of the solar cell.

[0138] As a possible implementation, see Figures 1 to 3 The first bus electrode 3 further includes: a second end pad disposed along the first direction A near the second edge of the first bus electrode connection line 30, and a second end bus electrode connected to the second end pad; the second end bus electrode includes at least two second sub-bus electrodes; the region between the two outermost second sub-bus electrodes constitutes the second end bus electrode region; the first hollow region 20 is also located within the second end bus electrode region; and the second hollow region 21 is also located outside the second end bus electrode region and between the first collecting electrodes. This further reduces parasitic absorption of light by the first passivation contact structure 2, improves light utilization, and thereby enhances the photoelectric conversion efficiency of the solar cell.

[0139] See also Figures 1 to 3 It should be noted that for the relevant description of the second end pad, the second end bus electrode and the second end bus electrode area, reference can be made to the previous description of the first end pad 31, the first end bus electrode and the first end bus electrode area, and no further details will be given here.

[0140] As a possible implementation, the solar cell further includes: a second passivation contact structure, a second bus electrode, and a second collector electrode. The second passivation contact structure is formed on the second surface of the semiconductor substrate; the second bus electrode is formed above the second passivation contact structure; and a plurality of second bus electrodes extend along the first direction and are spaced apart along the second direction. The second bus electrode includes a second bus electrode connecting line, a third end pad arranged in the second bus electrode connecting line near the first edge along the first direction, and a third end bus electrode connected to the third end pad; the third end bus electrode includes at least two third sub-bus electrodes extending along the first direction and spaced apart along the second direction; the area between the two outermost third sub-bus electrodes constitutes the third end bus electrode area; the second collecting electrode is formed above the second passivation contact structure; multiple second collecting electrodes extend along the second direction and are spaced apart along the first direction; the second bus electrode intersects with multiple second collecting electrodes; the second passivation contact structure has a fourth hollow area and a fifth hollow area; the fourth hollow area is located in the third end bus electrode area; the fifth hollow area is located outside the third end bus electrode area and is located between the second collecting electrodes.

[0141] Using the above-mentioned technical solution, the present application achieves dual optimization of optical and electrical performance by introducing a fourth hollow region within the third-end busbar region. This design significantly improves the effective utilization of incident light by reducing light absorption losses in the cell's power generation area, allowing more photons to participate in the photoelectric conversion process. More importantly, the inclusion of the fourth hollow region within the third-end busbar region addresses the current collection mismatch problem present in prior art, which involves low efficiency in collecting photogenerated carriers in certain regions due to uneven electric field distribution within the cell. By matching the fourth hollow region within the third-end busbar region with the fifth hollow region outside the third-end busbar region, the effective carrier collection efficiency in the electrode region is significantly improved while also effectively suppressing non-radiative recombination losses. This improves key performance parameters such as fill factor (FF) and open-circuit voltage (Voc) while simultaneously increasing short-circuit current (Jsc), ultimately significantly enhancing the overall conversion efficiency of the solar cell. Furthermore, the first and second hollow regions of the first passivation contact structure, as well as the fourth and fifth hollow regions of the second passivation contact structure, work together to improve the bifaciality of the solar cell. Furthermore, because the second collector electrode is formed above the second passivation contact structure and is electrically connected to the second passivation contact structure, this reduces contact resistivity and series resistance, effectively collecting current, reducing electrical losses and improving the efficiency of the solar cell. It also reduces the carrier transmission distance, thereby minimizing recombination losses during carrier transmission.

[0142] In one optional embodiment, the second bus electrode further includes: a fourth end pad disposed along the first direction in the second bus electrode connection line near the second edge, and a fourth end bus electrode connected to the fourth end pad. The fourth end bus electrode includes at least two fourth sub-bus electrodes; the region between the two outermost fourth sub-bus electrodes constitutes a fourth end bus electrode region; the fourth hollow region is also located within the fourth end bus electrode region; and the fifth hollow region is also located outside the fourth end bus electrode region and between the second collector electrodes. In this case, the parasitic absorption of light by the second passivation contact structure is further reduced, light utilization is improved, and thus the photoelectric conversion efficiency and bifaciality of the solar cell are improved.

[0143] It should be noted that for the relevant descriptions of the second passivation contact structure, the second collecting electrode, the fourth hollow area, the fifth hollow area, the third end pad, the third end bus electrode, the third end bus electrode area, the fourth end pad, the fourth end bus electrode and the fourth end bus electrode area, reference can be made to the previous descriptions of the relevant structures located on the first surface of the solar cell and will not be repeated here.

[0144] The solar cells in this application can be three types of solar cells from the perspective of the first bus electrode. It should be understood that the following description is only for understanding and is not intended to be a specific limitation.

[0145] The first solar cell: Figures 1 to 3 All first bus electrodes 3 include: a first end pad 31 close to the first edge 10 and a first end bus electrode connected to the first end pad 31 .

[0146] The second type of solar cell: Figures 1 to 3 All first bus electrodes 3 include: a first bus electrode connecting line 30, a first end pad 31 arranged in the first bus electrode connecting line 30 close to the first edge 10 along the first direction A, and a first end bus electrode connected to the first end pad 31.

[0147] The third type of solar cell: Figures 1 to 3 A portion of the first bus electrodes 3 includes: a first bus electrode connecting line 30, a first end pad 31 disposed along the first direction A within the first bus electrode connecting line 30 near the first edge 10, and a first end bus electrode connected to the first end pad 31. Another portion of the first bus electrodes 3 includes only the first end pad 31 near the first edge 10 and the first end bus electrode connected to the first end pad 31. The first bus electrodes 3 including the first bus electrode connecting lines 30 and the first bus electrodes 3 not including the first bus electrode connecting lines 30 are alternately arranged along the second direction B. Second hollow regions 21 are correspondingly formed at locations where the first bus electrode connecting lines 30 are not formed.

[0148] In some embodiments, see Figures 1 to 3 The first passivation contact structure 2 is formed correspondingly at the position where the first busbar electrode connecting line 30 is formed in the solar cell, and the position where the first busbar electrode connecting line 30 is not formed does not have the first passivation contact structure 2.

[0149] See also Figures 1 to 3When the above technical solution is adopted, the shielding of the semiconductor substrate by the first bus electrode connecting wire 30 is reduced, so that more light can reach the semiconductor substrate, the amount of photogenerated carriers generated is increased, and the short-circuit current and photoelectric conversion efficiency are improved. Furthermore, the amount of slurry used in the production of the first bus electrode connecting wire 30 is reduced (for example, the amount of silver paste is reduced), the raw material cost of the first bus electrode 3 is reduced, and the raw material cost of the solar cell is reduced. In addition, due to the large difference in thermal expansion coefficient between the first bus electrode 3 and the semiconductor substrate, the first bus electrode 3 is prone to generate thermal mismatch stress with the semiconductor substrate when the temperature changes, resulting in hidden cracks in the semiconductor substrate. In the present application, when the number of first bus electrode connecting wires 30 is reduced, the probability of hidden cracks in the semiconductor substrate can be reduced, and the yield of the solar cell can be improved.

[0150] In a second aspect, an embodiment of the present invention further provides a photovoltaic module. Figure 4 The photovoltaic module includes a cell string and an encapsulation layer; the cell string includes multiple conductive connectors 5 and multiple solar cells described in the above technical solution; the conductive connectors 5 connect the multiple solar cells in series; the encapsulation layer is used to cover the surface of the cell string.

[0151] The beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the solar cell described in the above technical solution, and will not be described in detail here.

[0152] The solar cell may be a TOPCon cell.

[0153] See also Figure 4 The conductive connector 5 can be a soldering ribbon or other connector for connecting solar cells. When the conductive connector 5 is a soldering ribbon, it can have a circular, triangular, or rectangular cross-section. Preferably, a soldering ribbon with a circular cross-section is used. This can mitigate mechanical stress at the solar cell connection, eliminate hidden cracks in high-density solar modules, and improve the reliability of solar modules.

[0154] As a possible implementation, see Figures 1 to 4When the solar cell includes a first end pad 31, a second end pad, a third end pad and a fourth end pad, the multiple spaced solar cells include adjacent first solar cells 6 and second solar cells 7; the conductive connector 5 includes a first connecting segment 50 located on the first surface of the first solar cell 6, a second connecting segment 51 located on the second surface of the second solar cell 7, and a third connecting segment 52 connecting the first connecting segment 50 and the second connecting segment 51; the first connecting segment 50 has a first end segment 53 and a second end segment 54, the first end segment 53 is welded to the first end pad of the first solar cell 6, and the second end segment 54 is welded to the second end pad of the first solar cell 6; the second connecting segment 51 includes a third end segment 55 and a fourth end segment 56, the third end segment 55 is welded to the third end pad of the second solar cell 7, and the fourth end segment 56 is welded to the fourth end pad of the second solar cell 7; the second end segment 54 and the third end segment 55 are connected by the third connecting segment 52.

[0155] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0156] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A solar cell, characterized in that: include: A semiconductor substrate comprising a first side and a second side facing each other; Along a first direction, the semiconductor substrate includes a first edge and a second edge opposite to each other; A first passivation contact structure is formed on the first surface of the semiconductor substrate; a first collector electrode formed above the first passivation contact structure; A plurality of the first collecting electrodes extend along the second direction and are spaced apart along the first direction; a first bus electrode formed above the first passivation contact structure; the first bus electrode intersecting with a plurality of the first collector electrodes; At least a portion of the first bus electrode includes: a first end pad proximate to the first edge and a first end bus electrode connected to the first end pad, the first end bus electrode being located between the first end pad and the first edge; The first end bus electrode includes at least two first sub-bus electrodes; The area between the two outermost first sub-bus electrodes constitutes a first end bus electrode area; The first passivation contact structure has a first hollow area and a second hollow area; the first hollow area is located in the first end bus electrode area; the second hollow area is located outside the first end bus electrode area and between the first collecting electrodes.

2. The solar cell according to claim 1, wherein At least part of the first bus electrode further includes: a first bus electrode connecting line, a plurality of the first bus electrode connecting lines extending along the first direction and spaced apart along the second direction; and the first end pad is arranged at one end of the first bus electrode connecting line close to the first edge.

3. The solar cell according to claim 1, wherein The first hollow area and the second hollow area have equal widths in the first direction; the first hollow area has a first center line extending along the second direction; Along the second direction, the second hollow area adjacent to the first hollow area has a second center line extending along the second direction; The first center line and the second center line are collinear; and / or, along the first direction, the ratio of the distance between the first center line and the second center line to the width of the first hollow area along the first direction or to the width of the second hollow area along the first direction is less than or equal to 10%.

4. The solar cell according to claim 1, wherein The first end bus electrode region has a plurality of first hollow regions spaced apart and distributed along the first direction.

5. The solar cell according to claim 4, wherein Two adjacent first hollow areas are staggered in the first direction.

6. The solar cell according to claim 2, wherein The distance between the two second hollow areas on both sides of the first end pad along the second direction is L1, and the distance between the two second hollow areas on both sides of the first bus electrode connection line along the second direction is L2, satisfying that L1 is greater than L2.

7. The solar cell according to claim 2, wherein Along the second direction, distances between the two second hollow regions located on both sides of the first bus electrode connecting line and the first bus electrode connecting line are not equal.

8. The solar cell according to claim 1, wherein Along the second direction, a distance between the first hollow area and an adjacent second hollow area is L5, and a distance between two adjacent first hollow areas along the first direction is L6, satisfying that L5 is greater than L6.

9. The solar cell according to claim 1 or 8, characterized in that Along the second direction, a distance L5 between the first hollow area and an adjacent second hollow area satisfies 50 μm ≤ L5 ≤ 1.5 mm; A distance between two adjacent first hollow areas along the first direction is L6, which satisfies 50 μm≤L6≤1 mm.

10. The solar cell according to claim 1, wherein A portion of the first collecting electrode adjacent to the first edge is disconnected at the first end bus electrode region, and the first passivation contact structure corresponding to the first collecting electrode penetrates the first end bus electrode region along an extension direction of the first collecting electrode.

11. The solar cell according to claim 1, wherein The size of the first hollow region closest to the first end pad is smaller than the size of the first hollow region far from the first end pad.

12. The solar cell according to claim 11, characterized in that The first hollow region closest to the first end pad is closer to the first collecting electrode located in the first end bus electrode region than the first end pad.

13. The solar cell according to claim 2, wherein The solar cell further comprises: Connecting pads, a plurality of connecting pads are arranged at intervals on the first bus electrode connecting line along the first direction; The length of the second hollow region located in the circumferential direction of the connecting pad along the second direction is smaller than the length of the second hollow region away from the connecting pad along the second direction.

14. The solar cell according to claim 1, wherein The distance between the first hollow area and the first sub-bus electrode is greater than the distance between the first hollow area and the first collecting electrode.

15. The solar cell according to claim 1 or 14, characterized in that The distance between the first hollow area and the first sub-bus electrode is greater than or equal to 50 μm and less than or equal to 1.5 mm; A distance between the first hollow region and the first collecting electrode is greater than or equal to 50 μm and less than or equal to 1 mm.

16. The solar cell according to claim 1, wherein For the same first-end bus electrode, along the direction approaching the first-end welding pad, the distance between the two outermost first sub-bus electrodes decreases, and the length of the first hollow area between the two adjacent first sub-bus electrodes decreases, and the length direction of the first hollow area is consistent with the second direction.

17. The solar cell according to claim 1, wherein For the same first end bus electrode, any two adjacent first sub-bus electrodes are parallel to each other; along the first direction, the length of the first hollow area between the two adjacent first sub-bus electrodes remains unchanged, and the length direction of the first hollow area is consistent with the second direction.

18. The solar cell according to claim 1, wherein The second hollow area includes a plurality of second sub-hollow areas; Along the second direction, a plurality of the second sub-hollow regions are distributed at intervals; and / or, along the second direction, a plurality of the second sub-hollow regions are abutted.

19. The solar cell according to claim 2, wherein The first surface of the semiconductor substrate includes a first region and a second region surrounding the first region; The first bus electrode and the first collecting electrode are located in the first area; The first passivation contact structure is located in both the first region and the second region; The first passivation contact structure further has a third hollow region, and the third hollow region is located in the second region and close to the first edge.

20. The solar cell according to claim 1, wherein The first end bus electrode includes three first sub-bus electrodes extending along the first direction and spaced apart along the second direction; The area between two adjacent first sub-bus electrodes constitutes a first sub-end bus electrode area; each of the first sub-end bus electrode areas has the first hollow area.

21. The solar cell according to claim 1, wherein The solar cell further comprises: a second passivation contact structure formed on the second surface of the semiconductor substrate; a second bus electrode formed above the second passivation contact structure; a plurality of the second bus electrodes extending along the first direction and spaced apart along the second direction; The second bus electrode includes: a second bus electrode connecting line, a third end pad provided in the second bus electrode connecting line close to the first edge along the first direction, and a third end bus electrode connected to the third end pad; The third end bus electrode includes at least two third sub-bus electrodes extending along the first direction and spaced apart along the second direction; the area between the two outermost third sub-bus electrodes constitutes the third end bus electrode area; a second collecting electrode formed above the second passivation contact structure; a plurality of the second collecting electrodes extending along the second direction and spaced apart along the first direction; and the second bus electrode intersecting with the plurality of the second collecting electrodes; The second passivation contact structure has a fourth hollow area and a fifth hollow area; the fourth hollow area is located in the third end bus electrode area; the fifth hollow area is located outside the third end bus electrode area and between the second collecting electrodes.

22. A photovoltaic module, characterized in that: Including battery strings and packaging layers; The cell string comprises a plurality of conductive connectors and a plurality of solar cells according to any one of claims 1 to 21; the conductive connectors connect the plurality of solar cells in series; The encapsulation layer is used to cover the surface of the battery string.

Images