Solar cell, solar module and method for manufacturing the same

Abstract

To provide a solar cell that reduces a risk of ineffective soldering, a solar module, and a method for manufacturing the same.SOLUTION: A solar cell includes a battery substrate 11, current collecting electrodes 12, bus electrode segments 13, and first connection units 14. The current collecting electrodes 12 extend along a first direction. Different current collecting electrodes 12 located on the same target surface owned by the battery substrate 11 are distributed at intervals along a second direction. The bus electrode segments 13 are located in an edge region at both ends of the target surface along the second direction, and extend along the second direction. The bus electrode segments 13 located at different ends of the same target surface along the second direction are provided in pairs to face each other. The bus electrode segments 13 are electrically coupled to corresponding current collecting electrodes 12 of the same conductivity type as itself. The first connection units 14 are disposed on a side of the corresponding bus electrode segments 13 opposite to the edge of the battery substrate 11 along the second direction, and is electrically coupled to the corresponding bus electrode segments 13.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to a solar cell, a solar module and a method for manufacturing the same. [Background technology]

[0002] Currently, solar cells have been widely used as an alternative means of new energy. Here, a photovoltaic solar cell is a device that converts solar light energy into electrical energy. Specifically, a solar cell uses the principle of photovoltaic power to generate carriers, and then extracts the carriers through electrodes, thereby contributing to the efficient use of electrical energy.

[0003] However, after conventional solar cells are connected in series via soldered connection members to form a solar module, the soldering stress of the soldered connection members at the edge regions of the solar cells is large, which can easily cause the soldering to become ineffective. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a solar cell, a solar module, and a manufacturing method thereof that can prevent high soldering stress on soldered connection members at the edge regions of the solar cell after the solar module is formed, and reduce the risk of ineffective soldering. [Means for solving the problem]

[0005] To achieve the above object, in a first aspect, the present invention provides a solar cell including a cell substrate, a collecting electrode, a bus electrode segment, and a first connection portion. At least one of the light-receiving surface and the non-light-receiving surface of the cell substrate is a target surface. The collecting electrode and the bus electrode segment are provided on the target surface of the cell substrate. The collecting electrodes extend along a first direction, and different collecting electrodes located on the same target surface are distributed at intervals along a second direction. The first direction is different from the second direction. The bus electrode segments are located in edge regions on both ends of the target surface along the second direction, and the bus electrode segments extend along the second direction. The bus electrode segments are electrically coupled to some collecting electrodes of the same conductivity type as the bus electrode segments. The first connection portion is provided on the side of the corresponding bus electrode segment opposite the edge of the cell substrate along the second direction, and is electrically coupled to the corresponding bus electrode segment.

[0006] When the above technical solution is adopted, the collecting electrodes and bus electrode segments included in the solar cell are provided on the target surface of the cell substrate. The bus electrode segments are electrically connected to some of the collecting electrodes of the same conductivity type as the collecting electrodes themselves. In this case, when the solar cell is in an operating state, carriers collected by the collecting electrodes located in the edge region of one end along the second direction of the target surface can be concentrated in the bus electrode segments. At the same time, the first connection portions included in the solar cell are provided on the side of the corresponding bus electrode segments opposite the edge of the cell substrate along the second direction. Based on this, after the solar cells provided by the present invention are connected in series with soldered connecting members to form a solar module, carriers collected by the current collecting electrodes located at one edge region along the second direction of the target surface can be concentrated simply by soldering the soldered connecting member to the first connection portion. The ends of the soldered connecting member do not need to extend to both edge regions along the second direction of the battery substrate. This shortens the effective soldering length of the soldered connecting member to the battery substrate, contributes to reducing soldering stress in the edge region along the second direction of the battery substrate, and further reduces the risk of ineffective soldering. At the same time, it also reduces the soldering accuracy requirements for the series soldering equipment and further reduces the difficulty of manufacturing the solar module. Secondly, it also prevents the ends of the soldered connecting members connected to two adjacent solar cells in the solar module from overlapping, causing a short circuit.

[0007] Next, the bus electrode segments are located in the edge regions at both ends along the second direction of the target surface. In other words, the length of the bus electrode segments included in the solar cell provided by the present invention is shorter than the length of the bus electrodes included in a conventional solar cell with a main grid. Based on this, compared with a conventional solar cell with a main grid, the solar cell provided by the present invention has a smaller total metal composite area between the collecting electrodes, the bus electrode segments, and the cell substrate, contributing to a higher open-circuit voltage of the solar cell and reducing the amount of material consumed in manufacturing the bus electrode segments, thereby contributing to lower solar cell manufacturing costs. Furthermore, among all the collecting electrodes located on the same target surface, the collecting electrodes electrically connected to the bus electrode segments are defined as first-type collecting electrodes, and the other collecting electrodes are defined as second-type collecting electrodes. Based on this, when solar cells provided by the present invention are connected in series with soldered connecting members to form a solar module, the soldered connecting members can be electrically connected to the second-type collecting electrodes without going through the bus electrodes. In this case, the transport path for transporting the carriers collected by the second type collecting electrode to the soldered connection member is short, which contributes to reducing transport losses and improves the operating efficiency of the solar module formed based on the solar cell provided by the present invention.

[0008] In one possible implementation, the side of the first connection portion opposite the bus electrode segment is not connected to the collecting electrode of the same conductivity type that is adjacent to it in the second direction. In this case, the number of collecting electrodes electrically coupled to the first connection portion is reduced, and carriers collected by the adjacent collecting electrode on the side opposite the bus electrode segment of the first connection portion can be transported directly to the soldered connection member, which contributes to a reduction in transport loss when transporting carriers collected by the adjacent collecting electrode on the side opposite the bus electrode segment of the first connection portion to the soldered connection member.

[0009] In one possible implementation, different bus electrode segments located at the same end of the same target surface along the second direction are distributed at intervals along the first direction, and the solar cell includes two bus electrode segments arranged opposite each other at different ends of the same target surface along the second direction. The two opposite bus electrode segments are not connected. In this case, the distribution of different bus electrode segments on the target surface is regular, contributing to reducing the difficulty of connecting adjacent solar cells to each other. At the same time, because the two opposite bus electrode segments are not connected, the total length of the two bus electrode segments arranged opposite each other along the second direction is shorter than the total length of the bus electrodes included in conventional solar cells, reducing metal composite loss between the bus electrode segments and the cell substrate and reducing the amount of consumable material used in manufacturing the bus electrode segments. At the same time, this contributes to ensuring low transport loss for carriers collected by a current collecting electrode arranged between the two opposite bus electrode segments.

[0010] In one possible implementation, the length of at least one bus electrode segment in the second direction is 10 mm or less.

[0011] When the above technical solution is adopted, the length of at least one bus electrode segment must be within the above range, thereby preventing the combined area of ​​the bus electrode segment and the cell substrate from becoming large due to the long length of the bus electrode segment. This ensures that the solar cell has a high open-circuit voltage, reduces the amount of consumable materials used in manufacturing the bus electrode segments, and reduces the loss of carriers collected by the current collecting electrode when they are transported to the soldered connection member.

[0012] In one possible implementation, the ratio between the length of the at least one bus electrode segment and the width of the battery substrate in the second direction is 12% or less, the beneficial effects of which can be seen from the analysis of the beneficial effects when the length of the at least one bus electrode segment is 10 mm or less described above, and will not be described again here.

[0013] In one possible implementation, the width of at least one bus electrode segment in the first direction is between 10 μm and 500 μm.

[0014] When the above technical solution is adopted, the width of at least one bus electrode segment in the first direction within the above range can prevent an increase in transport resistance of the bus electrode segment due to a small width, contributing to a reduction in transport loss of the bus electrode segment. Furthermore, the metal composite area between the bus electrode segment and the cell substrate can be prevented from being increased due to a large width of the bus electrode segment, ensuring a high open-circuit voltage for the solar cell and reducing the amount of consumable material used in manufacturing the bus electrode segment. Next, when the solar cell provided by the present invention is a back-contact type cell, the width of at least one bus electrode segment within the above range can prevent an increase in consumption of insulating material at the points where the current collecting electrodes located at both edge regions in the second direction of the target surface intersect with the bus electrode segment of the opposite conductivity type due to a large width of the bus electrode segment, or prevent a large gap at the points where the current collecting electrodes located at both edge regions in the second direction of the target surface intersect with the bus electrode segment of the opposite conductivity type, ensuring high carrier collection efficiency at the both edge regions in the second direction of the target surface.

[0015] In one possible implementation, the width of the bus electrode segment gradually increases in the direction approaching the first connection portion. In this case, the contact area between the bus electrode segment and the first connection portion increases, contributing to a reduction in transport loss. At the same time, the connection stability between the bus electrode segment and the first connection portion is further improved, thereby enhancing the reliability of the solar cell structure.

[0016] As one possible implementation, the number of bus electrode segments located at the same end along the second direction of the same target surface is 6 or more and 30 or less.

[0017] When the above technical solution is adopted, by keeping the number of bus electrode segments located at the same end in the second direction of the same target surface within the above range, it is possible to prevent carriers from having to transport a long path on the current collecting electrode to gather at the bus electrode segment due to a small number, thereby contributing to reducing transportation loss on the current collecting electrode and reducing the risk of the corresponding carriers not being able to be transported to the bus electrode segment after the current collecting electrode is broken. Furthermore, it is possible to prevent an increase in the metal composite area between all bus electrode segments located at both edge regions in the second direction of the target surface and the battery substrate due to a large number, which would increase the amount of consumable material used for at least all bus electrode segments.

[0018] In one possible implementation, the ratio between the number of collecting electrodes located in the edge region at one end of the target surface along the second direction and the total number of collecting electrodes located on the target surface is 12% or less. The beneficial effects of this case can be seen from the analysis of the beneficial effects when the number of bus electrode segments located at the same end of the same target surface along the second direction is 30 or less, as described above, and will not be described again here.

[0019] In one possible implementation, the first connection portion and the bus electrode segment electrically coupled thereto are of one unitary structure.

[0020] When the above technical solution is adopted, the fact that the first connection part and the bus electrode segment electrically connected thereto have an integrated structure means that the first connection part and the bus electrode segment electrically connected thereto are manufactured at the same time using the same material. Based on this, when the first connection part and the bus electrode segment electrically connected thereto have an integrated structure, there is no gap at the connection point between the first connection part and the bus electrode segment electrically connected thereto, which improves the contact performance between the first connection part and the bus electrode segment electrically connected thereto and contributes to reducing transport loss.

[0021] In one possible implementation, the solar cell further includes a first conductive material provided on the first connection portion, in which case, during the process of connecting the solar cells provided by the present invention in series to form a solar module, the soldering connection member can be soldered to the first connection portion via the first conductive material, ensuring good soldering quality between the soldering connection member and the first connection portion.

[0022] As one possible implementation, the length of the first connection portion in the first direction is not less than 100 μm and not more than 10,000 μm.

[0023] When the above technical solution is adopted, since the length of the first connection portion in the first direction is within the above range, it is possible to prevent the need for strict control over the placement position of the soldering connection member on the solar cell during the soldering process due to the short length of the first connection portion, prevent the soldering connection member from being misaligned and not being soldered to the first connection portion as required, and improve the soldering yield.Furthermore, it is possible to prevent the metal composite area between the first connection portion and the cell substrate from becoming large due to the long length of the first connection portion, and prevent the amount of consumable materials used in manufacturing the first connection portion from becoming large, thereby ensuring high operating efficiency of the solar cell and reducing the manufacturing cost of the solar cell.

[0024] In one possible implementation, the width of the first connection portion in the second direction is between 100 μm and 10,000 μm.

[0025] When the above technical solution is adopted, since the width of the first connection portion in the second direction is within the above range, it is possible to prevent a small contact area between the first connection portion and the soldered connection member due to a small width of the first connection portion, contribute to a decrease in soldering resistance between the first connection portion and the soldered connection member, contribute to an increase in solder adhesion between the first connection portion and the soldered connection member, reduce transport loss, and improve the structural reliability of a solar module formed based on the solar cell provided by the present invention. Furthermore, it is possible to prevent an increase in the combined area between the first connection portion and the cell substrate due to a large width of the first connection portion, which would increase the amount of consumable materials used in manufacturing the first connection portion, thereby ensuring high operating efficiency of the solar cell and reducing the manufacturing cost of the solar cell.

[0026] In one possible implementation, among all the current collecting electrodes located on the same target plane, the current collecting electrodes electrically coupled to the bus electrode segments are current collecting electrodes of the first type, and the other current collecting electrodes are current collecting electrodes of the second type. The solar cell also includes a second connection portion. The second connection portion is electrically connected to at least one current collecting electrode of the second type.

[0027] When the above technical solution is adopted, the second connection portion included in the solar cell is electrically coupled to a corresponding second-type current collecting electrode, and the second connection portion corresponds to at least one second-type current collecting electrode. In this case, when the solar cells provided by the present invention are connected in series using the soldering connection member to form a solar module, the soldering connection member can be soldered to the second-type current collecting electrode via the second connection portion. Compared to when the second-type current collecting electrode is electrically connected to the soldering connection member by forming the portion of the second-type current collecting electrode that is located in the extension direction of the first connection portion of the same conductivity type as the second-type current collecting electrode into a minute widened electrode segment, the contact area between the second connection portion and the soldering connection member is larger, which contributes to reducing the soldering resistance between the soldering connection member and the second-type current collecting electrode and improving the solder adhesion between the soldering connection member and the second-type current collecting electrode.

[0028] In one possible implementation, at least some of the second connection portions are arranged in parallel along the second direction, which contributes to a regular distribution of the second connection portions in the second direction, preventing the need for high installation accuracy for contacting the solder connection members with the different second connection portions by an automatic series soldering device due to a chaotic distribution of different second connection portions, and further contributes to reducing the difficulty of connecting adjacent solar cells to each other using the solder connection members.

[0029] In one possible implementation, the center lines of at least some of the second connection portions along the second direction are collinear with the center line of at least one bus electrode segment along the second direction. In this case, the center lines of at least some of the second connection portions are coextensive with the center line of at least one bus electrode segment in the second direction, which contributes to preventing the need for high installation accuracy by an automatic series soldering machine to bring the solder connection members into contact with the second connection portions and the first connection portions electrically coupled to the bus electrode segment, due to the two center lines along the second direction being misaligned, and further contributes to reducing the difficulty of connecting adjacent solar cells to each other using the solder connection members.

[0030] In one possible implementation, at least some of the second connection portions are arranged in parallel along the second direction. There are gaps between adjacent second connection portions in the second direction, and at least one current collecting electrode is either interrupted at the gap or continuous through the gap. In this case, after adjacent solar cells are connected to each other with the soldered connection member, the soldered connection member can be electrically spaced from the current collecting electrode of the opposite conductivity type at the intervals where the current collecting electrodes are interrupted by the gaps. This eliminates the need to install an insulating material such as an insulating adhesive, contributing to reduced solar cell interconnection costs and reducing the difficulty of installing an insulating material in the gaps.

[0031] In one possible implementation, the length of the second connection portion in the first direction is 100 μm or more and 10,000 μm or less. The beneficial effects in this case are similar to the beneficial effects in the case where the length of the first connection portion in the first direction is 100 μm or more and 10,000 μm or less, as described above, and will not be described again here.

[0032] In one possible implementation, the width of the second connection portion in the second direction is 100 μm or more and less than 500 μm. The beneficial effects in this case are similar to those of the first connection portion having a width of 500 μm or more and 10,000 μm or less in the second direction, as described above. Furthermore, when the solar cell provided by the present invention is a back-contact type cell, the width of the second connection portion in the second direction within this range can prevent the end of the second connection portion from overlapping with the adjacent collecting electrode of the opposite conductivity type, which would otherwise be caused by the large width of the second connection portion, and thus ensure high electrical reliability of the solar cell.

[0033] In one possible implementation, the width of the first connection portion is equal to or greater than the width of the second connection portion. In this case, a large contact area can be ensured between the first connection portion and the soldered connection member, contributing to a reduction in soldering resistance between the first connection portion and the soldered connection member and an improvement in solder adhesion between the first connection portion and the soldered connection member. Furthermore, it is possible to prevent the metal composite area between the second connection portion and the cell substrate from becoming large due to the large width of the second connection portion, ensuring high operational reliability of the solar cell.

[0034] In one possible implementation, the length of the first connection portion is equal to the length of the second connection portion.

[0035] When the above technical solution is adopted, the length of the first connection part and the length of the second connection part determine the effective contact size in the first direction between the solar cell and the soldered connection member. Furthermore, during the actual manufacturing process, there is a possibility that the soldered connection member may be misaligned on the solar cell due to equipment precision issues. Therefore, when the length of the first connection part is equal to the length of the second connection part in the first direction, this contributes to making the effective contact size in the first direction between the first connection part and the second connection part and the soldered connection member approximately the same, and ensures good contact between the soldered connection member and the first connection part and the second connection part.

[0036] In one possible implementation, the solar cell further includes a second conductive material provided at the second connection portion, and the beneficial effects of this case can be seen from the analysis of the beneficial effects of the solar cell further including the first conductive material described above, and will not be described again here.

[0037] In one possible implementation, the distances between adjacent bus electrode segments of opposite conductivity types and their ends adjacent to the battery substrate edge are unequal. In this case, the opposite conductivity type current collecting electrodes are alternately spaced apart along the second direction. In this case, the distances between the two opposite conductivity type current collecting electrodes adjacent to the battery substrate edge and the battery substrate edge are different in the second direction. Based on this, when the distances between adjacent bus electrode segments of opposite conductivity types and their ends adjacent to the battery substrate edge are unequal, the distance between the end of each bus electrode segment adjacent to the battery substrate edge and the battery substrate edge can be set according to the conductivity type of the bus electrode segment. This ensures that the bus electrode segment can extract carriers collected by the corresponding current collecting electrode, while reducing the distance between the end of the bus electrode segment adjacent to the battery substrate edge and the current collecting electrode of the same conductivity type, thereby contributing to reducing the risk of leakage current. This also reduces metal composite loss between the bus electrode segment and the battery substrate.

[0038] As one possible implementation, the edges of the plurality of first connection portions close to the bus electrode segment side may be flat or uneven. In this case, when the edges of the plurality of first connection portions close to the bus electrode segment side are flat, it contributes to providing the same surface area to the different first connection portions on the side opposite to the battery substrate, and further contributes to providing a large contact area between each first connection portion and the soldered connection member, ensuring good electrical contact characteristics and stable mechanical connection characteristics between the first connection portions and the soldered connection member. Note that for the beneficial effects of having the edges of the plurality of first connection portions close to the bus electrode segment side that are uneven, refer to the analysis of the beneficial effects when the distances between the ends of adjacent bus electrode segments of opposite conductivity type close to the battery substrate edge and the battery substrate edge are unequal, and will not be described again here.

[0039] In one possible implementation, the lengths of the bus electrode segments may be equal or unequal, and the beneficial effects of this case can be seen from the analysis above of the beneficial effects of flat or uneven edges of the first connection portions adjacent to the bus electrode segments, which will not be described again here.

[0040] In one possible implementation, the solar cell further includes an edge bus electrode, which is disposed at an edge of the cell substrate along the first direction and extends along the second direction. The maximum width of the edge bus electrode is smaller than the maximum width of the bus electrode segment. In this case, the presence of the edge bus electrode contributes to the extraction of carriers collected at the edge portion of the current collecting electrode along the first direction and prevents the edge portion of the current collecting electrode along the first direction from being broken, making carrier extraction impossible. This also prevents problems such as the current collecting electrode being interrupted at the intersection with a soldered connection member of the opposite conductivity type, making the collected carriers at the edge portion of the current collecting electrode along the first direction difficult to extract, thereby reducing power loss of the solar cell. Furthermore, having the maximum width of the edge bus electrode smaller than the maximum width of the bus electrode segment reduces metallurgical loss between the edge bus electrode and the cell substrate and contributes to reducing the difficulty of manufacturing the edge bus electrode in the edge region of the battery substrate along the first direction and the amount of consumable materials used.

[0041] In one possible implementation, the edge bus electrode is electrically coupled to at least some of the collecting electrodes of the same conductivity type as the edge bus electrode, and the ends of the collecting electrodes in the first direction that are electrically coupled to the edge bus electrode extend beyond the edge bus electrode, ensuring that the edge portions of the collecting electrodes in the first direction can be electrically coupled to the edge bus electrode and that carriers collected at the edge portions of the collecting electrodes in the first direction can be extracted via the edge bus electrode.

[0042] In one possible implementation, the solar cell further includes voltage measurement points on the bus electrode segments. In this case, since the bus electrode segments are relatively wide, placing the voltage measurement points on the bus electrode segments reduces the difficulty of contacting the measurement probe with the corresponding electrode, ensuring the accuracy of the measurement results. At the same time, if the solar cell is a back-contact type cell, this also helps prevent short-circuit problems.

[0043] In one possible implementation, the end of at least one bus electrode segment located at the edge of the battery substrate is electrically connected to itself, and the distance beyond the current collecting electrode located at the edge of the battery substrate is greater than 0 and less than 0.12 mm. In this case, the large distance reduces the distance between the end of the bus electrode segment adjacent to the edge region along the second direction of the target surface and the end of the battery substrate, which can lead to overlapping and short circuits after connecting two adjacent solar cells in series. This large distance also reduces the risk of leakage current due to a small distance between the end of the bus electrode segment adjacent to the edge region along the second direction of the target surface and the current collecting electrode of the opposite conductivity type located at the outermost edge of the edge region along the second direction of the target surface, ensuring high electrical reliability of the back-contact battery.

[0044] In one possible implementation, of all the bus electrode segments located at the same end of the non-light-receiving surface in the second direction, the two bus electrode segments located outermost in the first direction are first-type bus electrode segments, and the other bus electrode segments are second-type bus electrode segments. The first-type bus electrode segments are located outside of corresponding current collecting electrodes and close to one end of the cell substrate in the first direction, and the solar cell further includes connecting electrode segments, and the first-type bus electrode segments are electrically coupled to corresponding first connecting portions via the connecting electrode segments.

[0045] When the above technical solution is adopted, a first-type bus electrode segment is provided on the outer side of the battery substrate adjacent to one end of the corresponding current collecting electrode along the first direction, and the first-type bus electrode segment is electrically coupled to the corresponding first connection portion via the connecting electrode segment. In this case, there is no need to install an interruption point to electrically separate the current collecting electrode located in the edge region of the non-light-receiving surface along the second direction from the first-type bus electrode segment having the opposite conductivity type. This ensures that all carriers collected at each portion of the current collecting electrode located in the edge region of the non-light-receiving surface along the second direction can be transported to the corresponding bus electrode segment, improving carrier collection efficiency.

[0046] In one possible implementation, the solar cell is a back-contact type cell, and the target surface is only the non-light-receiving surface of the cell substrate. In this case, at least some of the current collecting electrodes located in the edge regions of both ends of the target surface along the second direction are discontinuous current collecting electrodes. The discontinuous current collecting electrodes have interruptions that separate them from second-type bus electrode segments of the opposite conductivity type, and both ends of the discontinuous current collecting electrodes along the first direction are separated from first-type bus electrode segments of the opposite conductivity type.

[0047] In one possible implementation, the current collecting electrodes that are not electrically connected to the bus electrode segments are interrupted between the two corresponding first connection portions that face each other, thereby preventing short circuits and improving the electrical reliability of the back-contact battery.

[0048] In one possible implementation, of all the collecting electrodes located in the edge regions at both ends along the second direction of the target surface, the collecting electrodes located on the outside are continuous collecting electrodes, and the other collecting electrodes are discontinuous collecting electrodes.

[0049] When the above technical solution is adopted, in actual application, the portion of the bus electrode segment adjacent to the edge region along the second direction of the target surface may extend to a current collecting electrode of the same conductivity type as the bus electrode segment and located at the edge, and in this case, the current collecting electrode located at the edge is made continuous, thereby preventing short circuits, increasing the carrier collection efficiency of the current collecting electrode located at the edge, and ensuring a small carrier recombination rate in the edge region along the second direction of the target surface.

[0050] In one possible implementation, the discontinuous collector electrode includes a plurality of collector electrode segments distributed at intervals along the first direction, and when the width of at least one bus electrode segment gradually increases along the direction approaching the first connection portion, the corresponding intervals between corresponding collector electrode segments of different pairs of opposite conductivity types to the same bus electrode segment are different, and each pair of collector electrode segments is two adjacent collector electrode segments included in the same collector electrode.

[0051] When the above technical solution is adopted, when the width of at least one bus electrode segment gradually increases in the direction approaching the first connection portion, the corresponding intervals between corresponding different pairs of collecting electrode segments of the opposite conductivity type to the same bus electrode segment are different. This prevents an increased risk of leakage current due to a small interval between the pair of collecting electrode segments corresponding to a large width of the same bus electrode segment, and also prevents an undesirable carrier collection ability due to a large interval between the pair of collecting electrodes corresponding to a small width of the same bus electrode segment, which contributes to improving the operating performance of the back-contact battery.

[0052] In one possible implementation, an end of at least one bus electrode segment close to the edge region along the second direction of the target surface extends to a side of the corresponding collector electrode electrically coupled to the bus electrode segment close to the edge region along the second direction of the target surface, thereby ensuring that the bus electrode segment can be electrically coupled to the collector electrode of the same conductivity type as the bus electrode segment and located outermost in the edge region along the second direction of the target surface, and that carriers collected by the collector electrode located outermost in the edge region along the second direction of the target surface can be extracted.

[0053] In one possible implementation, the end of the bus electrode segment adjacent to the first connection portion and the end of the first connection portion adjacent to the bus electrode segment are flat, or the end of the bus electrode segment adjacent to the first connection portion extends onto the portion of the first connection portion opposite the battery substrate. In this case, the end of the bus electrode segment adjacent to the first connection portion has the above two installation forms, which reduces the manufacturing difficulty of the bus electrode segments and ensures that the bus electrode segments can be electrically coupled to the corresponding first connection portions and that carriers collected in the bus electrode segments can be extracted via the first connection portions.

[0054] In a second aspect, the present invention provides a solar module including solar cells provided in the first aspect and various realizations thereof, and a soldering connection member for connecting adjacent solar cells in series, the soldering connection member being soldered to the first connection portion and having an end face extending beyond the first connection portion.

[0055] As one possible means for realizing this, the ratio of the length of the solder connection member that exceeds the first connection portion to the length of the bus electrode segment is 5% or more and 20% or less.

[0056] When the above technical solution is adopted, since the ratio of the length of the solder connection member beyond the first connection portion to the length of the bus electrode segment is within the above range, it is possible to prevent a small contact area between both ends of the solder connection member in the second direction and the first connection portion, which would otherwise be caused by this small ratio, and it is possible to ensure that the solder connection member can contact each area of ​​the surface of one side of the first connection portion opposite the battery substrate, thereby maintaining low contact resistance between the two. Furthermore, since carriers collected by the current collecting electrode between the first connection portion and the edge of the battery substrate can be transported to the solder connection member via the bus electrode segment and the first connection portion, having this ratio within the above range helps to prevent a large length of the solder connection member that does not need to be extended, which would result in a large amount of consumable material being used, and at the same time, it helps to prevent a large interconnection stress between the solder connection member and the bus electrode segment, which would otherwise be caused by this large ratio, when the solder connection member contacts the bus electrode segment, thereby improving the yield of solar cells.

[0057] In one possible implementation, the length of the soldered connection beyond the first connection portion is 2 mm or less.

[0058] In one possible implementation, the solder connection member and the bus electrode segment are in contact with each other, or there is a gap between them.

[0059] In a third aspect, the present invention provides a method for manufacturing a solar module, comprising the steps of first providing solar cells as described in the first aspect above and various implementations thereof, and then connecting adjacent solar cells in series using an infrared soldering process with soldered connecting members.

[0060] The beneficial effects of the second and third aspects of the present invention and their various implementations can be understood by referring to the analysis of the beneficial effects of the first aspect and its various embodiments, and will not be described here. [Brief explanation of the drawings]

[0061] The drawings described herein are intended to provide a further understanding of the present invention and to constitute a part of the present invention, and the exemplary embodiments of the present invention and their descriptions are intended to interpret the present invention and are not intended to unduly limit the present invention.

[0062] [Figure 1] FIG. 1 is a schematic diagram showing the distribution of electrode structures included in a solar cell with a main grid according to the related art. [Figure 2] 1 is a schematic diagram of the distribution of electrode structures included in a solar cell without a main grid in the related art; [Figure 3] 1 is a top view of the structure of the non-light-receiving surface side when the solar cell provided in the embodiment of the present invention is a back-contact type cell. [Figure 4] 2 is a top view 2 of the structure of the non-light-receiving surface side when the solar cell provided in the embodiment of the present invention is a back-contact type cell. [Figure 5] 1 is an enlarged schematic diagram 1 of a part of the structure of the non-light-receiving surface side when the solar cell provided in the embodiment of the present invention is a back-contact type cell. [Figure 6] 2 is an enlarged schematic diagram 2 of a part of the structure of the non-light-receiving surface side when the solar cell provided in the embodiment of the present invention is a back-contact type cell. [Figure 7] 3 is an enlarged schematic diagram 3 of a part of the structure of the non-light-receiving surface side when the solar cell provided in the embodiment of the present invention is a back-contact type cell. [Figure 8] 2 is a schematic diagram of the structure after the solar cells provided in the embodiment of the present invention are connected in series by soldering connecting members to form a solar module. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0063] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, it should be understood that these descriptions are merely illustrative and do not limit the scope of the present disclosure. In the following description, descriptions of known structures and techniques will be omitted to avoid unnecessary confusion with the concept of the present disclosure.

[0064] The drawings show various structural schematic diagrams according to embodiments of the present disclosure. These drawings are not drawn to scale, and some details may be enlarged and some details may be omitted for clarity. The shapes of various regions and layers shown in the drawings, as well as the relative sizes and positional relationships between them, are merely exemplary, and may vary in practice due to manufacturing tolerances and technical limitations. Furthermore, those skilled in the art can separately design regions / layers having different shapes, sizes, and relative positions according to actual needs.

[0065] In the context of the present disclosure, when a layer / element is described as being "on" another layer / element, this layer / element may be directly on top of this other layer / element, or there may be an intermediate layer / element therebetween. Also, if one layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, this layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions, and beneficial effects of the present invention clearer, the present invention will be described in more detail below in combination with figures and examples. It should be understood that the specific examples described herein are merely for the purpose of illustrating the present invention and are not intended to limit the present invention.

[0066] Additionally, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or the quantity of the technical features indicated. Thus, a feature qualified as "first" or "second" may expressly or imply the inclusion of one or more of that feature. In the description of the present invention, unless expressly and specifically limited, "plurality" means two or more than two. Unless expressly and specifically limited, "some" means one or more than one.

[0067] In describing the present invention, the terms "attach," "couple," and "connect" should be understood in a broad sense unless otherwise clearly defined or limited. For example, they may refer to fixed connection, detachable connection, integral connection, mechanical connection, electrical connection, direct connection, or indirect connection via an intermediate medium, or may refer to internal communication between two elements or an interaction between two elements. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0068] Currently, solar cells have been widely used as an alternative means of new energy. Here, a photovoltaic solar cell is a device that converts solar light energy into electrical energy. In actual operation, a solar cell uses the principle of photovoltaic power to generate carriers, and then extracts the carriers through electrodes, thereby contributing to the efficient use of electrical energy.

[0069] In practical applications, solar cells can be divided into solar cells with main grids and solar cells without main grids based on their electrode structure. The electrode structure of a solar cell with a main grid includes multiple collecting electrodes and at least one bus electrode. The different collecting electrodes extend along a first direction and are spaced apart along a second direction. The bus electrode extends along the second direction and is electrically connected to a collecting electrode of the same conductivity type as itself. As shown in FIG. 1, if the solar cell with a main grid is a back-contact type cell, the collecting electrode 12 is interrupted where it intersects with the bus electrode 24 of the opposite conductivity type to prevent leakage current. Alternatively, an insulating material can be installed to separate the collecting electrode 12 from the bus electrode 24 of the opposite conductivity type. Therefore, in a solar cell with a main grid, carriers collected by the collecting electrode 12 must pass through the bus electrode 24 to be collected at the connection point. This lengthens the carrier transport path, resulting in increased transport loss through the bus electrode 24. Secondly, the provision of bus electrodes 24 increases the composite area between the electrode structure and battery substrate 11, thereby reducing the open-circuit voltage of the solar cell. Furthermore, forming bus electrodes 24 requires the consumption of a large amount of electrode material, which is disadvantageous in reducing the manufacturing cost of solar cells.

[0070] As shown in FIG. 2, the electrode structure of a solar cell without a main grid does not include the bus electrode. The collecting electrodes 12 included in the solar cell without a main grid have widened electrode segments in a portion of their area along the first direction, and are soldered to the soldering connection members via the widened electrode segments. Based on this, the electrode structure included in the solar cell without a main grid has a small metal composite area with the battery substrate 11, but also a small soldering contact area with the soldering strip interconnect members via the widened electrode segments. This results in high soldering resistance and low soldering adhesion. Second, to extract all the carriers collected by all the collecting electrodes 12, soldering connection members must be soldered to the widened electrode segments of all the collecting electrodes 12. Furthermore, after soldering to form a solar module, the soldering connection members have a predetermined length. Furthermore, the soldering connection members and the battery substrate 11 undergo different degrees of deformation after soldering heating and cooling. This can lead to large soldering stress at the edges of the battery substrate 11, which can result in ineffective soldering. In addition, in the second direction, the distance between the outer collecting electrode 12 and the edge of the battery substrate 11 is small, making it easier for the edge collecting electrode 12 to break when soldering, and requiring high precision from the serial soldering equipment, making the solar module more difficult to manufacture.

[0071] To solve the above technical problems, in a first aspect, an embodiment of the present invention provides a solar cell. Specifically, in terms of the distribution position of the electrodes, the solar cell provided in the embodiment of the present invention may be a bifacial cell, i.e., one of the positive and negative electrodes of the solar cell is located on the light-receiving side of the cell substrate 11, and the other is located on the non-light-receiving side of the cell substrate 11. Alternatively, as shown in Figures 3 and 4, the solar cell provided in the embodiment of the present invention may be a back-contact cell, i.e., both the positive and negative electrodes of the solar cell are located on the non-light-receiving side of the cell substrate 11.

[0072] In terms of division, the solar cell provided in the embodiment of the present invention may be a full-cell solar cell, or may be a cut solar cell as shown in Figures 3 and 4. Here, the embodiment of the present invention does not specifically limit the cut factor of the cut solar cell. For example, the cut solar cell may be a 1 / 2 cut solar cell, a 1 / 3 cut solar cell, or a 1 / 4 cut solar cell.

[0073] As shown in FIGS. 3 and 4 , a solar cell provided in an embodiment of the present invention includes a cell substrate 11, a collecting electrode 12, a bus electrode segment 13, and a first connection portion 14. At least one of the light-receiving surface and the non-light-receiving surface of the cell substrate 11 is a target surface. The collecting electrode 12 and the bus electrode segment 13 are disposed on the target surface of the cell substrate 11. The collecting electrodes 12 extend along a first direction, and different collecting electrodes 12 located on the same target surface are spaced apart along a second direction. The first direction is different from the second direction. The bus electrode segments 13 are located on both edge regions of the target surface along the second direction, and extend along the second direction. Each bus electrode segment 13 is electrically coupled to some of the collecting electrodes 12 of the same conductivity type as itself. The first connection portion 14 is disposed on the side of the corresponding bus electrode segment 13 opposite the edge of the cell substrate 11 along the second direction and is electrically coupled to the corresponding bus electrode segment 13.

[0074] When the above technical solution is adopted, as shown in Figures 3 and 4, the collecting electrodes 12 and bus electrode segments 13 included in the solar cell are provided on the target surface of the cell substrate 11. Furthermore, the bus electrode segments 13 are electrically connected to some of the collecting electrodes 12 of the same conductivity type as themselves. In this case, when the solar cell is in an operating state, carriers collected by the collecting electrodes 12 located in the edge region at one end along the second direction of the target surface can be concentrated in the bus electrode segments 13. At the same time, the first connecting portions 14 included in the solar cell are provided on the side of the corresponding bus electrode segments 13 opposite to the edge of the cell substrate 11 along the second direction. Based on this, as shown in Figures 3, 4, and 8, after the solar cells provided in the embodiment of the present invention are connected in series with the solder connection members 23 to form a solar module, the solder connection members 23 are simply soldered to the first connection portions 14 to aggregate carriers collected by the current collecting electrodes 12 located at one edge region along the second direction of the target surface. The ends of the solder connection members 23 do not need to extend to both edge regions along the second direction of the battery substrate 11. This shortens the effective soldering length of the solder connection members 23 to the battery substrate 11, reduces soldering stress in the edge regions along the second direction of the battery substrate 11, and further reduces the risk of ineffective soldering. At the same time, this also reduces the soldering accuracy requirements for the series soldering equipment and further simplifies the manufacturing process of the solar module. Second, it also prevents the ends of the solder connection members 23 connected to two adjacent solar cells in the solar module from overlapping, causing a short circuit. 3 and 4, the bus electrode segments 13 are located in the edge regions at both ends along the second direction of the target surface. In other words, the length of the bus electrode segments 13 included in the solar cell provided in the embodiment of the present invention is shorter than the length of the bus electrode included in a conventional solar cell with a main grid.Based on this, compared to a conventional solar cell with a main grid, the solar cell provided by the embodiment of the present invention has a smaller combined area of ​​the collecting electrodes 12, the bus electrode segments 13, and the cell substrate 11, which contributes to a higher open-circuit voltage of the solar cell and reduces the amount of material consumed in manufacturing the bus electrode segments 13, thereby contributing to lower solar cell manufacturing costs. Furthermore, among all the collecting electrodes 12 located on the same surface, the collecting electrodes 12 electrically connected to the bus electrode segments 13 are defined as first-type collecting electrodes 15, and the other collecting electrodes 12 are defined as second-type collecting electrodes 16. Based on this, when solar cells provided by the embodiment of the present invention are connected in series with soldered connecting members to form a solar module, the soldered connecting members can be electrically connected to the second-type collecting electrodes 16 without passing through the bus electrodes. In this case, the transport path for transporting carriers collected by the second-type collecting electrodes 16 to the soldered connecting members is shorter, which contributes to reduced transport loss and improves the operating efficiency of solar modules formed based on the solar cells provided by the embodiment of the present invention.

[0075] In the actual application process, the embodiments of the present invention do not specifically limit the structure and material of the cell substrate, and whether the light-receiving surface and non-light-receiving surface of the cell substrate are target surfaces, and these can be determined according to the type of solar cell and the actual use case, and no specific limitations are provided here.

[0076] For example, when the solar cell provided in the embodiment of the present invention is a bifacial solar cell, the cell substrate may include a semiconductor substrate and a doped semiconductor layer formed on the light-receiving or non-light-receiving side of the semiconductor substrate. The doped semiconductor layer has the opposite conductivity type to that of the semiconductor substrate. In the above case, only the light-receiving surface of the cell substrate may be the target surface, or the non-light-receiving surface of the cell substrate may be the target surface, or both the light-receiving surface and the non-light-receiving surface of the cell substrate may be the target surface.

[0077] Specifically, the material of the semiconductor substrate may be a semiconductor material such as silicon, germanium silicon, germanium, or gallium arsenide. The conductivity type of the semiconductor substrate may be N-type or P-type. Regarding the doped semiconductor layer, when the conductivity type of the semiconductor substrate is N-type, the conductivity type of the doped semiconductor layer is P-type, and when the conductivity type of the semiconductor substrate is P-type, the conductivity type of the doped semiconductor layer is N-type. Next, the material of the doped semiconductor layer may be a semiconductor material such as silicon, germanium, silicon carbide, or gallium arsenide. In terms of the internal arrangement form of the material, the doped semiconductor layer may be amorphous, microcrystalline, single crystalline, nanocrystalline, polycrystalline, or the like.

[0078] For example, when the solar cell provided in the embodiments of the present invention is a back-contact solar cell, the semiconductor substrate may include a semiconductor substrate and a doped semiconductor layer formed on or within a portion of the non-light-receiving surface of the semiconductor substrate. The doped semiconductor layer has an opposite conductivity type to that of the semiconductor substrate. In this case, during the actual manufacturing process of the semiconductor substrate, a single doped semiconductor layer can be formed to completely cover the non-light-receiving surface of the semiconductor substrate, and two doped regions of opposite conductivity types can be formed on the non-light-receiving surface by simply removing a portion of the doped semiconductor layer located on the non-light-receiving surface. This solves the problem of complex solar cell manufacturing processes due to the need to perform two opposite-conductivity doping operations on the non-light-receiving surface.

[0079] Specifically, when the semiconductor substrate includes the semiconductor substrate and a doped semiconductor layer formed on a partial region of the non-light-receiving surface of the semiconductor substrate, the material and conductivity type of the semiconductor substrate and the doped semiconductor layer may refer to the material and conductivity type of the semiconductor substrate and the doped semiconductor layer included in the semiconductor substrate when the solar cell is a bifacial solar cell, as described above, and will not be described again here.

[0080] In some cases, the semiconductor substrate may further include a passivation layer located between the semiconductor substrate and the doped semiconductor layer. The passivation layer can passivate at least the surface where the semiconductor substrate and the doped semiconductor layer contact each other, thereby reducing the rate at which carriers recombine at the contact point between the two. The doped semiconductor layer formed on the passivation layer can selectively collect carriers of the corresponding conductivity type in the semiconductor substrate, further improving the photoelectric conversion efficiency of the solar cell provided in this embodiment. Specifically, the material of the passivation layer can be determined according to the material of the doped semiconductor layer.

[0081] For example, when the doped semiconductor layer is a doped amorphous silicon layer, a doped microcrystalline silicon layer, or a doped amorphous silicon-microcrystalline silicon mixed layer, the passivation layer may be an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, or an intrinsic amorphous silicon-microcrystalline silicon mixed layer, and the doped semiconductor layer and the passivation layer may form a heterocontact structure.

[0082] Furthermore, for example, when the doped semiconductor layer is a doped polycrystalline silicon layer, the passivation layer is a tunnel passivation layer. In this case, the doped semiconductor layer and the passivation layer can form a tunnel passivation contact structure. The material of the tunnel passivation layer may include any dielectric material that has a tunnel passivation function. For example, the material of the tunnel passivation layer may include one or more of silicon oxide, aluminum oxide, titanium oxide, hafnium dioxide, gallium oxide, tantalum pentoxide, niobium pentoxide, silicon nitride, silicon carbonitride, aluminum nitride, titanium nitride, and titanium carbonitride.

[0083] In the above case, when the solar cell provided in the embodiment of the present invention is a back-contact type cell, only the non-light-receiving surface of the cell substrate is the target surface, and the collecting electrodes, bus electrode segments, and first connection portions are located only on the non-light-receiving surface side of the cell substrate.

[0084] Regarding the collecting electrodes, the embodiment of the present invention does not specifically limit the texture structure, number and distribution of the collecting electrodes, which can be determined according to the type and actual use of the solar cell.

[0085] For example, when the solar cell provided in the embodiments of the present invention is a bifacial solar cell, different collecting electrodes located on the same target surface have the same conductivity type, and the collecting electrodes may be continuous or discontinuous.

[0086] 3 and 4, when the solar cell provided in the embodiment of the present invention is a back-contact type cell, among all the bus electrode segments 13 located at the same end in the second direction of the non-light-receiving surface, the two bus electrode segments 13 located at the outermost positions in the first direction are defined as first-type bus electrode segments 18, and the other bus electrode segments 13 are defined as second-type bus electrode segments 19. Based on this, the first-type current collecting electrode 15 may be a continuous current collecting electrode, and in this case, the first-type current collecting electrode 15 may be separated from the bus electrode segments 13 of the opposite conductivity type by an insulating material to prevent short circuits.

[0087] Alternatively, as shown in Figures 3 and 4, at least some of the first-type current collecting electrodes 15 may be discontinuous current collecting electrodes, and first-type bus electrode segments 18 may be located outside and adjacent to one end of the cell substrate in the first direction of the corresponding current collecting electrode 12. The solar cell further includes connecting electrode segments 20, and the first-type bus electrode segments 18 are electrically coupled to the corresponding first connection portions 14 via the connecting electrode segments 20. In this case, the interruptions in the discontinuous current collecting electrodes are used to space second-type bus electrode segments 19 of the opposite conductivity type thereto, and both ends of the discontinuous current collecting electrodes in the first direction are spaced from the first-type bus electrode segments 18 of the opposite conductivity type thereto. In this case, the first-type bus electrode segments 18 are located outside and adjacent to one end of the cell substrate in the first direction of the corresponding current collecting electrode 12, and the first-type bus electrode segments 18 are electrically coupled to the corresponding first connection portions 14 via the connecting electrode segments 20. In this case, there is no need to install an interruption point to electrically separate the collecting electrodes 12 located in the edge regions of the non-light-receiving surface along the second direction from the bus electrode segments 18 of the first type, which has the opposite conductivity type to the collecting electrodes themselves. This ensures that all carriers collected at each portion of the collecting electrodes 12 located in the edge regions of the non-light-receiving surface along the second direction can be transported to the corresponding bus electrode segments, thereby improving carrier collection efficiency.

[0088] Specifically, the present invention does not specifically limit the size of the interruption of the discontinuous collecting electrode or the texture structure of the connecting electrode segment, as long as they are applicable to the solar cell provided by the present invention. Here, all of the first-type collecting electrodes may be discontinuous collecting electrodes. Alternatively, among all of the collecting electrodes located in the edge regions at both ends along the second direction of the target surface, the outermost collecting electrodes are continuous collecting electrodes, and the other collecting electrodes are discontinuous collecting electrodes. In this case, in actual application, the portion of the bus electrode segment adjacent to the edge region along the second direction of the target surface may have the opposite conductivity type and extend to the edge-located collecting electrode. In this case, making the edge-located collecting electrode continuous can prevent short circuits, increase the carrier collection efficiency of the edge-located collecting electrode, and ensure a low carrier recombination rate in the edge region along the second direction of the target surface.

[0089] As shown in FIG. 3 , the second-type current collecting electrode 16 may be a continuous current collecting electrode. In this case, the solar cell may further include an insulating material (not shown). The insulating material is provided on the portion of the current collecting electrode 12 (i.e., the second-type current collecting electrode 16) that is not electrically connected to the bus electrode segment 13, located between two corresponding first connection portions 14 that face each other. Alternatively, as shown in FIG. 4 , the second-type current collecting electrode 16 may be a discontinuous current collecting electrode. In other words, the current collecting electrode 12 that is not electrically connected to the bus electrode segment 13 is interrupted between two corresponding first connection portions 14 that face each other. In this case, the soldered connection member can be separated from the first-type current collecting electrode 15 (the current collecting electrode 12 that is not electrically connected to the bus electrode segment 13) of the opposite conductivity type by either providing or interrupting the insulating material, thereby preventing a short circuit.

[0090] The type and size of the insulating material can be determined according to the actual application, and are not specifically limited herein. For example, the insulating material may be an insulating adhesive, etc.

[0091] For example, the length of the insulating material in the first direction may be 1 mm or more and 5 mm or less. For example, the length of the insulating material may be 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. In this case, by keeping the length of the insulating material in the first direction within the above range, it is possible to prevent a short circuit from occurring, as it would be difficult to separate the soldered connection member from the collecting electrode of the opposite conductivity type via the insulating material due to the short length of the insulating material. Furthermore, it is possible to prevent the use of a large amount of consumable material corresponding to the insulating material due to the long length of the insulating material, thereby contributing to reducing the manufacturing costs of solar cells.

[0092] For example, the width of the insulating material in the second direction may be 1 mm or more and 10 mm or less. For example, the width of the insulating material may be 1 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm. In this case, by keeping the width of the insulating material in the second direction within the above range, it is possible to prevent a situation in which a small width of the insulating material prevents the insulating material from completely covering the corresponding portion of the first type collecting electrode, making it difficult to separate the solder connection member from the collecting electrode of the opposite conductivity type via the insulating material, thereby preventing a short circuit. Furthermore, it is possible to prevent a situation in which a large width of the insulating material causes the insulating material to cover only a portion of the adjacent collecting electrode (or second connection portion) and thereby reduce the contact area between the collecting electrode (or second connection portion) and the solder connection member.

[0093] The second type of current collecting electrode may have an expanded electrode segment, so that the second type of current collecting electrode is soldered to the soldering strip interconnection member via the expanded electrode segment, and in the second direction, the expanded electrode segment of the second type of current collecting electrode is disposed between two opposing first connection portions of the same conductivity type.

[0094] Alternatively, as shown in Figures 3 and 4, the solar cell further includes a second connection portion 17. The second connection portion 17 is electrically connected to a corresponding second-type current collecting electrode 16, and the second connection portion 17 has the same conductivity type as the first connection portion 14 and is located between two opposing first connection portions 14. The second connection portion 17 is electrically connected to at least one second-type current collecting electrode 16. In this case, the second connection portion 17 included in the solar cell is electrically connected to the corresponding second-type current collecting electrode 16, and the second connection portion 17 corresponds to at least one second-type current collecting electrode 16. In this case, when the solar cells provided in the embodiment of the present invention are connected in series using a soldering connection member to form a solar module, the soldering connection member can be soldered to the second-type current collecting electrode 16 via the second connection portion 17. By making the portion of the second type collecting electrode 16 that is located in the extension direction along the second direction of the first connection portion 14 of the same conductivity type as the second type collecting electrode 16 into a minute widened electrode segment, the contact area between the second connection portion 17 and the soldering connection member is larger than when electrically connected to the soldering connection member, which reduces the soldering resistance between the soldering connection member and the second type collecting electrode 16 and contributes to improving the soldering adhesion between the soldering connection member and the second type collecting electrode 16.

[0095] Specifically, the embodiment of the present invention does not specifically limit the size and texture structure of the second connection part, as long as they are applicable to the solar cell provided in the embodiment of the present invention.

[0096] For example, the length of the second connection portion in the first direction may be 100 μm or more and 10,000 μm or less. For example, the length of the second connection portion may be 100 μm, 500 μm, 1,000 μm, 3,000 μm, 6,000 μm, 9,000 μm, or 10,000 μm. In this case, by having the width of the second connection portion in the first direction within the above range, it is possible to prevent the need for strict control over the placement of the soldering connection member on the solar cell during the soldering process due to the small width of the second connection portion, prevent the soldering connection member from being misaligned and not being soldered to the second connection portion as desired, and improve soldering yield. Furthermore, it is possible to prevent the combined area of ​​the second connection portion and the cell substrate from being large due to the large width of the second connection portion, which would increase the amount of consumable materials used in manufacturing the second connection portion. This ensures high operating efficiency of the solar cell and reduces manufacturing costs of the solar cell.

[0097] For example, the width of the second connection portion in the second direction may be 100 μm or more and less than 500 μm. For example, the width of the second connection portion may be 100 μm, 200 μm, 300 μm, 400 μm, or 500 μm. In this case, by having the length of the second connection portion in the second direction within the above range, it is possible to prevent a small contact area between the second connection portion and the solder connection member due to a small length of the second connection portion, thereby contributing to a decrease in soldering resistance between the second connection portion and the solder connection member, contributing to an increase in solder adhesion between the second connection portion and the solder connection member, reducing transport loss, and improving the structural reliability of a solar module formed based on a solar cell provided by an embodiment of the present invention. Furthermore, it is possible to prevent a large combined area between the second connection portion and the cell substrate due to a large length of the second connection portion, which would increase the amount of consumable materials used in manufacturing the second connection portion. This ensures high operating efficiency of the solar cell and reduces manufacturing costs of the solar cell. In addition, as shown in Figures 3 and 4, when the solar cell provided in the embodiment of the present invention is a back-contact type cell, the width of the second connection part 17 in the second direction is within the above range, which prevents the end of the second connection part 17 from overlapping with the adjacent collecting electrode 12 of the opposite conductivity type, which would otherwise be caused by the large width of the second connection part 17, and ensures high electrical reliability of the solar cell.

[0098] As described above, when the solar cell provided in the embodiment of the present invention further includes an insulating material provided on the second type of collecting electrode, the length of the insulating material along the first direction may be equal to the length of the second connecting portion, or may be longer than the length of the second connecting portion, in which case the soldering connection member is prevented from overlapping with a collecting electrode of the opposite conductivity type due to misalignment of the soldering connection member on the solar cell, thereby preventing a short circuit.

[0099] Specifically, when the length of the insulating material is greater than the length of the second connecting portion, the difference between the length of the insulating material and the length of the second connecting portion can be determined according to the accuracy of the serial soldering equipment used to form the solar module and the actual use case, and is not specifically limited here.

[0100] In some cases, the solar cell further includes a second conductive material disposed at the second connection portion. In this case, when the solar cells provided in the embodiment of the present invention are connected in series to form a solar module, the solder connection member can be soldered to the second connection portion via the second conductive material, ensuring good soldering quality between the solder connection member and the second connection portion. Specifically, the second conductive material can be a conductive material such as a conductive adhesive, tin, or silver.

[0101] Regarding the distribution of the different second connection portions, as shown in Figures 3 and 4, at least some of the second connection portions 17 may be arranged in parallel along the second direction. Alternatively, the different second connection portions may be distributed in an alternating offset manner along the second direction. Here, when at least some of the second connection portions 17 may be arranged in parallel along the second direction, this contributes to the regular distribution of the second connection portions 17 in the second direction, preventing the need for high installation accuracy when contacting the solder connection members with the different second connection portions 17 by an automatic series soldering device, which would be caused by the chaotic distribution of the different second connection portions 17, and further contributes to reducing the difficulty of connecting adjacent solar cells to each other using the solder connection members.

[0102] 3 and 4, the center line of at least some of the second connection portions 17 along the second direction may be collinear with the center line of at least one bus electrode segment 13 along the second direction. Alternatively, the center line of at least some of the second connection portions may not be collinear with the center line of at least one bus electrode segment 13 along the second direction, but may be approximately parallel to the center line of at least one bus electrode segment 13 along the second direction. Alternatively, the center line of at least some of the second connection portions may be oblique with respect to the center line of at least one bus electrode segment along the second direction. Here, when the center line of at least some of the second connection portions 17 along the second direction is collinear with the center line of at least one bus electrode segment 13 along the second direction, the center line of at least some of the second connection portions 17 is on the same extension line as the center line of at least one bus electrode segment 13 in the second direction, which contributes to preventing the automatic series soldering machine from requiring high installation precision to contact the solder connection members with the second connection portions 17 and the first connection portions 14 electrically coupled to the bus electrode segments 13, respectively, due to the two center lines along the second direction being misaligned, and further contributes to reducing the difficulty of connecting adjacent solar cells to each other using the solder connection members.

[0103] As shown in FIGS. 3 and 4 , at least some of the second connection portions 17 are arranged parallel to one another in the second direction, and there is a gap between each second connection portion 17 and an adjacent second connection portion 17 in the second direction. In this case, at least one collecting electrode 12 is interrupted at the gap or is continuous through the gap. In this case, after adjacent solar cells are connected to each other with a soldered connection member, the soldered connection member can be electrically separated from the opposite conductive collecting electrode 12 at the intervals where the collecting electrodes 12 are interrupted by the gap. This eliminates the need for an insulating material such as an insulating adhesive, contributing to reduced solar cell interconnection costs and reducing the difficulty of installing an insulating material in the gap. The size of the gap between each second connection portion 17 and an adjacent second connection portion 17 can be determined depending on the spacing between adjacent collecting electrodes 12 and the size of the second connection portion 17, and is not specifically limited herein. The distance at which the at least one current collecting electrode 12 is interrupted by the gap can be determined according to the actual use case, and may be any distance that is applicable to the solar cell provided in the embodiment of the present invention.

[0104] With regard to the bus electrode segments, embodiments of the present invention do not specifically limit the texture structure of the bus electrode segments or the number of bus electrode segments, as long as carriers collected by the collecting electrodes located at both edges along the second direction of the target surface can be transported to the first connection portion via the bus electrode segments.

[0105] For example, the width of at least one bus electrode segment in the first direction may be 500 μm or less. For example, the width of at least one bus electrode segment may be 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, or 500 μm. In this case, by having the width of at least one bus electrode segment in the first direction within this range, it is possible to prevent an increase in the metal composite area between the bus electrode segment and the cell substrate due to a large width of the bus electrode segment, thereby ensuring a high open-circuit voltage for the solar cell and reducing the amount of consumable materials used in manufacturing the bus electrode segment. Next, when the solar cell provided in the embodiment of the present invention is a back-contact type cell, the width of at least one bus electrode segment within the above range can further prevent excessive consumption of insulating material at the intersection of the current collecting electrodes located at both edge regions along the second direction of the target surface with the bus electrode segment of the opposite conductivity type, which would otherwise be caused by the large width of the bus electrode segment, or prevent large interruptions at the intersection of the current collecting electrodes located at both edge regions along the second direction of the target surface with the bus electrode segment of the opposite conductivity type, thereby ensuring high carrier collection efficiency at both edge regions along the second direction of the target surface. Here, the connection portion can be a solder portion. The solder portion is used to connect to a soldering connection member.

[0106] Specifically, the widths of the bus electrode segments along the second direction may be the same or different, and the size relationship between the widths of the bus electrode segments along the second direction can be determined according to the shape requirements for the bus electrode segments in actual use cases.

[0107] For example, the width of the bus electrode segment gradually increases in the direction approaching the first connection portion. In this case, the contact area between the bus electrode segment and the first connection portion is increased, contributing to a reduction in transport loss. At the same time, the connection stability between the bus electrode segment and the first connection portion is further improved, thereby enhancing the reliability of the solar cell structure. Specifically, the width of the bus electrode segment may increase linearly or parabolically in the direction approaching the first connection portion.

[0108] In the solar cell provided in the embodiment of the present invention, when the solar cell is a back-contact type cell, as described above, at least some of the current collecting electrodes located in the edge regions of both ends of the target surface along the second direction are discontinuous current collecting electrodes. The discontinuous current collecting electrodes include a plurality of current collecting electrode segments distributed at intervals along the first direction. Furthermore, when the width of at least one bus electrode segment gradually increases in a direction approaching the first connection portion, the corresponding intervals between corresponding different pairs of current collecting electrode segments of the opposite conductivity type to the same bus electrode segment may be the same or different, and each pair of current collecting electrode segments is two adjacent current collecting electrode segments included in the same current collecting electrode. When the corresponding intervals between corresponding different pairs of current collecting electrode segments of the opposite conductivity type to the same bus electrode segment are different, this can prevent an increased risk of leakage current due to a small interval between the pair of current collecting electrode segments corresponding to a large width of the same bus electrode segment, and also prevent undesirable carrier collection capability due to a large interval between the pair of current collecting electrode segments corresponding to a small width of the same bus electrode segment, thereby contributing to improved operating performance of the back-contact type cell.

[0109] Specifically, when the width of at least one bus electrode segment gradually increases along a direction approaching the first connection portion, the corresponding spacing between a different pair of collecting electrode segments of the opposite conductivity type to that of the same bus electrode segment can be determined according to the widths of different regions of the bus electrode segments and the leakage prevention requirements in actual use cases, and is not specifically limited herein.

[0110] Regarding the specific shape of the bus electrode segments, for example, the cross-sectional shape of the bus electrode segments may be rectangular, trapezoidal, elliptical, diamond-shaped, or the like.

[0111] It should be understood that, within a certain range, the longer the length of a bus electrode segment, the greater the number of collecting electrodes electrically connected to the bus electrode segment, and the greater the distance from the corresponding end of the soldered connection member connecting different solar cells in series to the edge region of one end of the battery substrate along the second direction, resulting in a smaller soldering stress. However, the longer the bus electrode segment, the greater the combined area of ​​the bus electrode segment and the battery substrate, which increases the corresponding amount of consumable material used and increases the loss of transporting carriers collected by the collecting electrodes located at the edge region of the target surface along the second direction to the soldered connection member. Based on this, the length of the bus electrode segment and the ratio of the length of the bus electrode segment to the width of the battery substrate can be determined according to the requirements for the soldering stress, combined area, transport loss, etc. in actual use cases.

[0112] For example, the length of at least one bus electrode segment in the second direction may be 10 mm or less. For example, the length of at least one bus electrode segment in the second direction may be 1 mm or more and 7 mm or less. For example, the length of at least one bus electrode segment may be 1 mm, 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm, etc. In this case, by ensuring that the length of at least one bus electrode segment is within the above range, it is possible to prevent an increase in the metal composite area between the bus electrode segment and the cell substrate due to the long length of the bus electrode segment, ensuring a high open-circuit voltage for the solar cell, reducing the amount of consumable materials used in manufacturing the bus electrode segment, and reducing the loss of carriers collected by the current collecting electrode during transport to the soldered connection member.

[0113] For example, in the second direction, the ratio between the length of the at least one bus electrode segment and the width of the battery substrate may be 12% or less. For example, the ratio between the length of the at least one bus electrode segment and the width of the battery substrate may be 4.5%, 5%, 7%, 9%, 10%, or 12%, etc. The beneficial effects in this case can be seen from the analysis of the beneficial effects when the length of the at least one bus electrode segment is 10 mm or less described above, and will not be described again here.

[0114] Specifically, the lengths of the bus electrode segments may be equal or unequal. Having the bus electrode segments of equal length simplifies the pattern complexity of the electrode structure of the solar cell and reduces the manufacturing difficulty of the electrode structure. The opposite conductivity type current collecting electrodes are alternately spaced apart along the second direction. The distances between the two opposite conductivity type current collecting electrodes closest to the edge of the battery substrate and the edge of the battery substrate are different in the second direction. Based on this, when the lengths of the bus electrode segments are unequal, the length of each bus electrode segment can be set according to its conductivity type. This ensures that the bus electrode segment can extract carriers collected by the corresponding current collecting electrode. This also reduces the distance between the end of the bus electrode segment closest to the edge of the battery substrate and the current collecting electrode of the same conductivity type, thereby reducing the risk of leakage current. Furthermore, this also reduces metal composite loss between the bus electrode segment and the battery substrate.

[0115] The distances between adjacent bus electrode segments of opposite conductivity types, from their ends adjacent to the edge of the battery substrate to the edge of the battery substrate, may be equal or may not be equal. The beneficial effects of unequal distances between adjacent bus electrode segments of opposite conductivity types, from their ends adjacent to the edge of the battery substrate to the edge of the battery substrate, can be understood by reference to the analysis of the beneficial effects of unequal lengths of multiple bus electrode segments described above, and will not be described again here.

[0116] Here, the end of at least one bus electrode segment close to the edge region along the second direction of the target surface can be in contact with the corresponding collecting electrode electrically coupled to it, or the end of at least one bus electrode segment close to the edge region along the second direction of the target surface can extend to the side of the corresponding collecting electrode electrically coupled to it close to the edge region along the second direction of the target surface. In this case, it is possible to ensure that the bus electrode segment can be electrically coupled to the collecting electrode of the same conductivity type as the bus electrode segment and located at the outermost edge region along the second direction of the target surface, and to ensure that carriers collected by the collecting electrode located at the outermost edge region along the second direction of the target surface can be extracted.

[0117] The end of the bus electrode segment adjacent to the first connection portion may be flush with the end of the first connection portion adjacent to the bus electrode segment, or may extend over the portion of the first connection portion on the opposite side of the battery substrate. In this case, the end of the bus electrode segment adjacent to the first connection portion has the above two installation configurations, which reduces the manufacturing difficulty of the bus electrode segment and ensures that the bus electrode segment can be electrically coupled to the corresponding first connection portion and that carriers collected in the bus electrode segment can be extracted via the first connection portion.

[0118] Specifically, the distance by which the end of at least one bus electrode segment adjacent to the edge region along the second direction of the target surface extends to the side of the corresponding collecting electrode electrically coupled to it adjacent to the edge region along the second direction of the target surface, and the length by which the end of the bus electrode segment adjacent to the first connection portion extends onto the portion of the first connection portion opposite the battery substrate can be determined according to actual manufacturing precision and actual needs, and are not specifically limited here.

[0119] For example, the distance at which the end of at least one bus electrode segment located at the edge of the battery substrate is electrically coupled to itself and extends beyond the current collecting electrode located at the edge of the battery substrate may be greater than 0 and less than 0.12 mm. For example, the distance at which the end of at least one bus electrode segment located at the edge of the battery substrate is electrically coupled to itself and extends beyond the current collecting electrode located at the edge of the battery substrate may be 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm, 0.1 mm, 0.11 mm, etc. In the above case, the large distance reduces the distance between the end of the bus electrode segment adjacent to the edge region of the target surface along the second direction and the end of the battery substrate, which can lead to a short circuit caused by overlapping of the bus electrode segments after connecting two adjacent solar cells in series. Furthermore, the large distance reduces the distance between the end of the bus electrode segment adjacent to the edge region of the target surface along the second direction and the current collecting electrode of the opposite conductivity type located at the outermost side of the edge region of the target surface along the second direction, which can lead to an increased risk of leakage current. This ensures high electrical reliability for back-contact batteries.

[0120] The length of the bus electrode segment also determines the number of collecting electrodes located in an edge region at one end of the target surface along the second direction. Based on this, the number of collecting electrodes located in an edge region at one end of the target surface along the second direction and the ratio of the number of collecting electrodes located in an edge region at one end of the target surface along the second direction to the total number of collecting electrodes located on the target surface can be determined according to the length of the bus electrode segment, the spacing between the collecting electrodes, and the width of the collecting electrodes.

[0121] For example, the ratio between the number of collecting electrodes located in an edge region at one end of the target surface along the second direction and the total number of all collecting electrodes located on the target surface may be 12% or less. For example, the ratio between the number of collecting electrodes located in an edge region at one end of the target surface along the second direction and the total number of all collecting electrodes located on the target surface may be 4.5%, 5%, 7%, 9%, 10%, 12%, etc. For the beneficial effects in this case, refer to the analysis of the beneficial effects when the number of bus electrode segments located at the same end of the same target surface along the second direction is 30 or less, as described above, and will not be described again here.

[0122] The number of bus electrode segments determines the length of the carrier transport path in the corresponding region of the current collecting electrode and the combined area of ​​the bus electrode segments and the battery substrate. Therefore, the number of bus electrode segments can be determined depending on the requirements for transport loss and combined area in actual use cases.

[0123] For example, the number of bus electrode segments located on the same side of the same target surface along the second direction may be 6 to 30 inclusive. For example, the number of bus electrode segments located on the same side of the same target surface along the second direction may be 6, 8, 10, 15, 20, 25, or 30, etc. In this case, keeping the number of bus electrode segments located on the same end of the same target surface along the second direction within the above range prevents carriers from having to transport a long path on the current collecting electrode to gather at a bus electrode segment, which would be caused by a small number. This contributes to reducing transport losses and the risk of not being able to transport corresponding carriers to a bus electrode segment after the current collecting electrode is broken. Furthermore, it also prevents an increase in the combined area between all bus electrode segments located on both edge regions of the target surface along the second direction and the battery substrate, which would be caused by a large number, which would increase the amount of consumable material used for at least all bus electrode segments.

[0124] As shown in Figures 3 and 4, different bus electrode segments 13 located at the same end of the same target surface along the second direction are spaced apart along the first direction, and the solar cell includes two bus electrode segments 13 arranged opposite each other at different ends of the same target surface along the second direction. The two opposite bus electrode segments 13 are not connected. This provides a regular distribution of the different bus electrode segments 13 on the target surface, reducing the difficulty of connecting adjacent solar cells to each other. At the same time, because the two opposite bus electrode segments 13 are not connected, the total length of the two opposite bus electrode segments 13 along the second direction is shorter than the total length of the bus electrodes included in conventional solar cells. This reduces metal composite loss between the bus electrode segments 13 and the cell substrate 11 and reduces the amount of consumable material used in manufacturing the bus electrode segments 13. This also contributes to low transport loss of carriers collected by the current collecting electrode 12 between the two opposite bus electrode segments 13.

[0125] In one example, the solar cell may further include a voltage measurement point provided on the bus electrode segment. In this case, since the bus electrode segment has a relatively large width, providing the voltage measurement point on the bus electrode segment reduces the difficulty of contacting the measurement probe with the corresponding electrode, thereby ensuring the accuracy of the measurement results. At the same time, if the solar cell is a back-contact type cell, this also helps prevent short-circuit problems. Specifically, the specific location of the voltage measurement point on the bus electrode segment can be determined according to actual needs. For example, the voltage measurement point may be provided at the intersection of the bus electrode segment and the current collecting electrode.

[0126] 4 , the solar cell may further include an edge bus electrode 25, which is provided at an end of the cell substrate 11 along the first direction and extends along the second direction. The maximum width of the edge bus electrode 25 is smaller than the maximum width of the bus electrode segment 13. In this case, the presence of the edge bus electrode 25 contributes to extracting carriers collected at the edge portions of the current collecting electrode 12 along the first direction, preventing the edge portions of the current collecting electrode 12 along the first direction from being broken, making carriers impossible to extract. Alternatively, the current collecting electrode 12 may be interrupted at a point where it intersects with a soldered connection member of the opposite conductivity type, making it impossible or difficult to extract carriers collected at the edge portions of the current collecting electrode 12 along the first direction. This reduces power loss in the solar cell. Furthermore, since the maximum width of the edge bus electrode 25 is smaller than the maximum width of the bus electrode segment 13, this reduces the metal composite loss between the edge bus electrode 25 and the battery substrate 11, and contributes to reducing the difficulty of manufacturing the edge bus electrode 25 in the edge region along the first direction of the battery substrate 11 and the amount of consumable materials used.

[0127] Specifically, the width of the edge bus electrode can be determined according to the actual use case and is not specifically limited herein. Note that, when the edge bus electrode is electrically coupled to at least some of the collecting electrodes of the same conductivity type as the edge bus electrode, the edge of the collecting electrode electrically coupled to the edge bus electrode along the first direction can be in contact with the edge bus electrode. Alternatively, the edge of the collecting electrode electrically coupled to the edge bus electrode along the first direction can extend beyond the edge bus electrode. In this case, it is ensured that the edge portion of the collecting electrode along the first direction can be electrically coupled to the edge bus electrode, and that carriers collected at the edge portion of the collecting electrode along the first direction can be extracted via the edge bus electrode.

[0128] Regarding the first connection portion, the bus electrode segment electrically coupled to at least one first connection portion may have a non-integrated structure. Alternatively, the bus electrode segment electrically coupled to at least one first connection portion may have an integrated structure. Here, the term "integrated structure" for the bus electrode segment electrically coupled to at least one first connection portion refers to the bus electrode segment electrically coupled to at least one first connection portion being manufactured simultaneously using the same material. Based on this, when the bus electrode segment electrically coupled to at least one first connection portion has an integrated structure, there is no gap at the connection point between the at least one first connection portion and the bus electrode segment electrically coupled to it, which improves the contact performance between the first connection portion and the bus electrode segment electrically coupled to it, thereby contributing to reducing transport loss.

[0129] The size of the first connection portion can be determined according to the requirements for soldering resistance and soldering adhesion between the solder connection member and the first connection portion, and the combined area of ​​the first connection portion and the battery substrate in an actual use case.

[0130] For example, the length of the first connection portion in the first direction may be 100 μm or more and 10,000 μm or less. For example, the length of the first connection portion may be 100 μm, 500 μm, 1,000 μm, 3,000 μm, 6,000 μm, 9,000 μm, or 10,000 μm. In this case, by having the length of the first connection portion in the first direction within the above range, it is possible to prevent the need for strict control over the placement position of the soldering connection member on the solar cell during the soldering process due to the short length of the first connection portion, prevent the soldering connection member from being misaligned and not being soldered to the first connection portion as desired, and improve soldering yield. Furthermore, it is possible to prevent the combined area of ​​the first connection portion and the cell substrate from being large due to the long length of the first connection portion, which would increase the amount of consumable materials used in manufacturing the first connection portion. This ensures high operating efficiency of the solar cell and reduces manufacturing costs of the solar cell.

[0131] For example, the width of the first connection portion in the second direction may be 100 μm to 10,000 μm inclusive. For example, the width of the first connection portion may be 100 μm, 1,000 μm, 3,000 μm, 6,000 μm, 9,000 μm, or 10,000 μm. In this case, by having the width of the first connection portion in the second direction within the above range, it is possible to prevent a small contact area between the first connection portion and the solder connection member due to the small width of the first connection portion, thereby contributing to a decrease in soldering resistance between the first connection portion and the solder connection member, contributing to an increase in solder adhesion between the first connection portion and the solder connection member, reducing transport loss, and improving the structural reliability of a solar module formed based on a solar cell provided by an embodiment of the present invention. Furthermore, the large width of the first connection portion prevents the combined area of ​​the first connection portion and the battery substrate from becoming large, which would increase the amount of consumable materials used in manufacturing the first connection portion. This ensures that the solar cell has high operating efficiency and reduces the manufacturing cost of the solar cell.

[0132] Specifically, the width of the first connection portion may be equal to the width of the second connection portion. Alternatively, as shown in Figures 3 and 4, the width of the first connection portion 14 may be greater than the width of the second connection portion 17. In this case, the contact area between the first connection portion 14 and the soldered connection member can be increased, contributing to a reduction in the soldering resistance between the first connection portion 14 and the soldered connection member and an improvement in the solder adhesion between the first connection portion 14 and the soldered connection member. Furthermore, the larger width of the second connection portion 17 prevents the combined area between the second connection portion 17 and the battery substrate 11 from becoming larger, thereby ensuring high operational reliability of the solar cell.

[0133] Specifically, when the width of the first connection portion is greater than the width of the second connection portion, the difference between the two can be determined according to the actual use case, and is not specifically limited here.

[0134] 3 and 4, the length of the first connection portion 14 may be equal to the length of the second connection portion 17. Of course, the length of the first connection portion 14 does not have to be equal to the length of the second connection portion 17. The lengths of the first connection portion 14 and the second connection portion 17 affect the effective contact size between the first connection portion 14 and the soldered connection member in the first direction. During actual manufacturing, there is a possibility that the soldered connection member may be misaligned on the solar cell due to equipment precision issues. Therefore, when the length of the first connection portion 14 is equal to the length of the second connection portion 17 in the first direction, the effective contact size between the first connection portion 14 and the second connection portion 17 and the soldered connection member in the first direction is approximately the same, ensuring good contact between the soldered connection member and the first connection portion 14 and the second connection portion 17.

[0135] 3 and 4, the side of the first connection portion 14 opposite the bus electrode segment 13 is not connected to the adjacent current collecting electrode 12 of the same conductivity type along the second direction. This contributes to a reduction in the number of current collecting electrodes 12 electrically coupled to the first connection portion 14, and therefore carriers collected by the adjacent current collecting electrode 12 on the side opposite the bus electrode segment 13 of the first connection portion 14 can be transported directly to the soldered connection member, contributing to a reduction in transport loss when transporting carriers collected by the adjacent current collecting electrode 12 on the side opposite the bus electrode segment 13 of the first connection portion 14 to the soldered connection member.

[0136] The edges of the first connection portions adjacent to the bus electrode segments may be flat or uneven. In this case, when the edges of the first connection portions adjacent to the bus electrode segments are flat, it contributes to ensuring that the different first connection portions have the same surface area on the side opposite to the battery substrate, and further contributes to ensuring a large contact area between each first connection portion and the soldered connection member, ensuring good electrical contact characteristics and stable mechanical connection characteristics between the first connection portions and the soldered connection member. For the beneficial effects of uneven edges of the first connection portions adjacent to the bus electrode segments, refer to the analysis of the beneficial effects when the distances between the ends of adjacent opposite conductivity type bus electrode segments adjacent to the battery substrate edge and the battery substrate edge are unequal, and will not be described again here.

[0137] For example, when the edges of the first connection portions close to the bus electrode segment side are flat, the lengths of the different bus electrode segments may not be equal. When the edges of the first connection portions close to the bus electrode segment side are not flat, the lengths of the different bus electrode segments may preferably be equal, so that the structure formed by the first connection portions and the bus electrode segments in contact with them has approximately the same total length along the second direction, which contributes to making the magnitude of the currents aggregated at the different first connection portions the same and contributes to reducing power loss.

[0138] In some cases, the solar cell may further include a first conductive material provided at the first connection portion. In this case, when the solar cells provided in the embodiment of the present invention are connected in series to form a solar module, the soldering connection member can be soldered to the first connection portion via the first conductive material, ensuring good soldering quality between the soldering connection member and the first connection portion. Here, the type of the first conductive material can refer to the determination of the type of the second conductive material described above, and is not specifically limited here.

[0139] 3, 4, and 7, the first connection portion 14 located on the outer side in the first direction is defined as having a first end 21 and a second end 22 arranged opposite each other in the second direction, and the second end 22 is closer to the edge of the battery substrate 11 in the second direction than the first end 21. In this case, the conductivity type of the collector electrode 12 adjacent to the outer side of the second end 22 may be the same as the conductivity type of the first connection portion 14 located on the outer side. Alternatively, as shown in FIG. 7, the conductivity type of the collector electrode 12 adjacent to the outer side of the second end 22 may be opposite to the conductivity type of the first connection portion 14 located on the outer side.

[0140] In a second aspect, an embodiment of the present invention provides a solar module including solar cells provided in the first aspect and various implementations thereof, and a soldering connection member for connecting adjacent solar cells in series, the soldering connection member being soldered to the first connection portion and having an end face extending beyond the first connection portion.

[0141] In one possible implementation, the solder connection member and the bus electrode segment are in contact with each other, or there is a gap between them.

[0142] As one possible means for realizing this, the ratio of the length of the solder connection member that exceeds the first connection portion to the length of the bus electrode segment is 5% or more and 20% or less.

[0143] When the above technical solution is adopted, since the ratio of the length of the solder connection member beyond the first connection portion to the length of the bus electrode segment is within the above range, it is possible to prevent a small contact area between both ends of the solder connection member in the second direction and the first connection portion, which would otherwise be caused by this small ratio, and it is possible to ensure that the solder connection member can contact each area of ​​the surface of one side of the first connection portion opposite the battery substrate, thereby maintaining low contact resistance between the two. Furthermore, since carriers collected by the current collecting electrode between the first connection portion and the edge of the battery substrate can be transported to the solder connection member via the bus electrode segment and the first connection portion, having this ratio within the above range helps to prevent a large length of the solder connection member that does not need to be extended, which would result in a large amount of consumable material being used, and at the same time, it helps to prevent a large interconnection stress between the solder connection member and the bus electrode segment, which would otherwise be caused by this large ratio, when the solder connection member contacts the bus electrode segment, thereby improving the yield of solar cells.

[0144] In one possible implementation, the length of the soldered connection beyond the first connection portion is 2 mm or less.

[0145] An embodiment of the present invention further provides a method for manufacturing a solar cell, particularly a method for forming an electrode structure. The manufacturing method is used to print a collecting electrode, a bus electrode segment, a connecting portion (including the first connecting portion and the second connecting portion) and an insulating adhesive layer on a passivation layer of a cell substrate. The manufacturing method for a solar cell specifically includes the following steps 1, 2, and 3:

[0146] In step 1, a current collecting electrode is printed on the passivation layer of the battery substrate. In the next step, when the bus electrode segments and connection parts are printed, the current collecting electrode is dried at a low temperature of 300°C to 400°C to prevent deformation or damage to the formed current collecting electrode.

[0147] In step 2, the bus electrode segments and connectors are printed. The current collecting electrodes, bus electrode segments, and connectors are simultaneously sintered at a high temperature of 700°C to 800°C, melting and fusing the current collecting electrodes, bus electrode segments, and connectors to each other, forming stable connections. The current collecting electrodes then penetrate the passivation layer to connect to the corresponding doped semiconductor layer included in the battery substrate, forming good ohmic contact. High-temperature sintering allows the bus electrode segments and connectors to withstand greater tensile forces and achieve higher soldering stability. During this process, the bus electrode segments and connectors can be selectively brought into contact with the doped semiconductor layer or not.

[0148] In step 3, an insulating adhesive layer is printed. Because the insulating adhesive layer cannot withstand high-temperature sintering, it is printed after the high-temperature sintering of the current collecting electrode is completed. After the insulating adhesive layer hardens at a temperature of 300°C to 400°C, it comes into sufficient contact with the current collecting electrode and firmly adheres to it, forming an insulating layer.

[0149] In a third aspect, an embodiment of the present invention provides a method for manufacturing a solar module, comprising the steps of first providing solar cells as described in the first aspect above and various implementations thereof, and then connecting adjacent solar cells in series using an infrared soldering process with soldered connecting members.

[0150] In the embodiments of the present invention, the beneficial effects of the second and third aspects and various implementation forms thereof may refer to the analysis of the beneficial effects of the first aspect and various implementation forms thereof, and will not be described again here.

[0151] The above description does not provide a detailed description of the technical details of each layer, such as the structure and etching of each layer. However, those skilled in the art should understand that layers, regions, etc. of desired shapes can be formed using various technical means. Furthermore, those skilled in the art can design methods that are not completely identical to the methods described above to form the same structure. Furthermore, although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used together.

[0152] The above describes the embodiments of the present disclosure. However, these embodiments are merely for illustrative purposes and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is limited by the appended claims and their equivalents. Those skilled in the art can make various substitutions and modifications without departing from the scope of the present disclosure, and all of these substitutions and modifications are intended to fall within the scope of the present disclosure. [Explanation of symbols]

[0153] 11 Battery board 12 Current collecting electrode 13 Bath electrode segments 14 First connection part 15 First type current collecting electrode 16 Second type current collecting electrode 17 Second connection part 18 Type 1 bus electrode segments 19 Second type bus electrode segment 20 connecting electrode segments 21 1st end 22 2nd end 23 Soldered connection parts 24 Bus electrode 25 Edge bus electrode

Claims

1. a battery substrate, a current collecting electrode, a bus electrode segment, and a first connection portion; At least one of the light-receiving surface and the non-light-receiving surface of the battery substrate is a target surface; the collecting electrodes and the bus electrode segments are provided on the target surface of the battery substrate, the collecting electrodes extend along a first direction, different collecting electrodes located on the same target surface are distributed at intervals along a second direction, the first direction is different from the second direction, the bus electrode segments are located in edge regions of both ends of the target surface along the second direction, the bus electrode segments extend along the second direction, and the bus electrode segments are electrically coupled to some of the collecting electrodes of the same conductivity type as themselves, the first connection portion is provided on the side of the bus electrode segment opposite to the edge of the cell substrate along the second direction, and is electrically coupled to the corresponding bus electrode segment.

2. 2. The solar cell according to claim 1, wherein the side of the first connection portion opposite to the bus electrode segment is not connected to the collector electrode adjacent to it along the second direction and of the same conductivity type.

3. 2. The solar cell according to claim 1, wherein different bus electrode segments located at the same end of the same target surface along the second direction are distributed at intervals along the first direction, and the solar cell includes two bus electrode segments arranged opposite each other at different ends of the same target surface along the second direction, and the two opposite bus electrode segments are not connected.

4. the length of at least one of the bus electrode segments in the second direction is 10 mm or less; and / or the ratio between the length of at least one of the bus electrode segments and the width of the cell substrate in the second direction is 12% or less; and / or a width of at least one of the bus electrode segments in the first direction is between 10 μm and 500 μm; and / or the width of at least one of the bus electrode segments gradually increases along a direction adjacent to the first connection portion; and / or The solar cell according to claim 1 , wherein the number of the bus electrode segments located on the same end of the same target surface along the second direction is 6 to 30.

5. 2. The solar cell according to claim 1, wherein a ratio between the number of the collecting electrodes located in an edge region at one end of the target surface along the second direction and the total number of all collecting electrodes located on the target surface is 12% or less.

6. the bus electrode segment electrically coupled to the first connection portion is an integral structure; and / or The solar cell according to claim 1 , further comprising a first conductive material provided on the first connection portion.

7. The length of the first connection portion in the first direction is not less than 100 μm and not more than 10,000 μm, and / or The solar cell according to claim 1 , wherein the width of the first connection portion in the second direction is 100 μm or more and 10,000 μm or less.

8. Among all the current collecting electrodes located on the same target plane, the current collecting electrode electrically coupled to the bus electrode segment is a first type current collecting electrode, and the other current collecting electrodes are second type current collecting electrodes; 8. The solar cell according to claim 1, further comprising a second connection portion, the second connection portion being electrically coupled to at least one of the second type current collecting electrodes.

9. At least some of the second connection portions are arranged in parallel along the second direction, and / or 9. The solar cell according to claim 8, wherein a center line of at least some of the second connection portions along the second direction is collinear with a center line of at least one of the bus electrode segments along the second direction.

10. 9. The solar cell according to claim 8, wherein at least some of the second connection portions are arranged in parallel along the second direction, there is a gap between one second connection portion and another second connection portion adjacent to the one second connection portion in the second direction, and at least one of the current collecting electrodes is interrupted at the gap or is continuous through the gap.

11. The length of the second connection portion in the first direction is not less than 100 μm and not more than 10,000 μm, and / or The width of the second connection portion in the second direction is equal to or greater than 100 μm and less than 500 μm, and / or the width of the first connection portion is equal to or greater than the width of the second connection portion; and / or the length of the first connection portion is equal to the length of the second connection portion; and / or The solar cell according to claim 8 , further comprising a second conductive material provided in the second connection portion.

12. 8. The solar cell of claim 1, wherein adjacent bus electrode segments of opposite conductivity type are spaced unequal from their ends proximate the cell substrate edge to the cell substrate edge.

13. 8. The solar cell according to claim 1, wherein edges of the plurality of first connection portions adjacent to the bus electrode segments are either flat or not flat.

14. 8. The solar cell according to claim 1, wherein the lengths of the bus electrode segments are equal or unequal.

15. 8. The solar cell according to claim 1, further comprising an edge bus electrode, the edge bus electrode being provided at an end of the cell substrate along the first direction and extending along the second direction, and the maximum width of the edge bus electrode being smaller than the maximum width of the bus electrode segment.

16. 16. The solar cell of claim 15, wherein the edge bus electrode is electrically coupled to at least some of the collecting electrodes of the same conductivity type as the edge bus electrode, and an end of the collecting electrode along the first direction that is electrically coupled to the edge bus electrode extends beyond the edge bus electrode.

17. The solar cell according to claim 1 , further comprising a voltage measurement point provided on the bus electrode segment.

18. 8. The solar cell according to claim 1, wherein an end of at least one bus electrode segment located at an edge of the cell substrate is electrically connected to itself, and a distance beyond the current collecting electrode located at the edge of the cell substrate is greater than 0 and less than 0.12 mm.

19. 8. The solar cell according to claim 1, wherein, of all the bus electrode segments located at the same end of the non-light-receiving surface along the second direction, the two bus electrode segments located at the outermost positions along the first direction are first-type bus electrode segments, and the other bus electrode segments are second-type bus electrode segments, the first-type bus electrode segments are located outside one end of the corresponding current collecting electrode that is close to an edge of the cell substrate along the first direction, the solar cell further includes connection electrode segments, and the first-type bus electrode segments are electrically coupled to the corresponding first connection portions via the connection electrode segments.

20. the solar cell is a back-contact type cell, and the target surface is only the non-light-receiving surface of the cell substrate; 20. The solar cell of claim 19, wherein at least some of the collecting electrodes located in edge regions at both ends along the second direction of the target surface are discontinuous collecting electrodes, and the discontinuous collecting electrodes are separated from the second-type bus electrode segments of the opposite conductivity type by interruptions in the discontinuous collecting electrodes, and both ends of the discontinuous collecting electrodes along the first direction are separated from the first-type bus electrodes of the opposite conductivity type.

21. The current collecting electrodes that are not electrically coupled to the bus electrode segments are provided with an interruption in a portion between two corresponding first connection portions that are provided opposite to each other; and / or 21. The solar cell according to claim 20, wherein, of all the collecting electrodes located in the edge regions at both ends along the second direction of the target surface, the collecting electrodes located on the outer sides are continuous collecting electrodes, and the other collecting electrodes are discontinuous collecting electrodes.

22. the discontinuous collecting electrode includes a plurality of collecting electrode segments distributed at intervals along the first direction; 21. The solar cell according to claim 20, wherein when the width of at least one of the bus electrode segments gradually increases along a direction approaching the first connection portion, corresponding intervals between the collector electrode segments of corresponding different pairs of opposite conductivity types to the same bus electrode segment are different, and the collector electrode segments of each pair are two adjacent collector electrode segments included in the same collector electrode.

23. an end of at least one of the bus electrode segments adjacent to an edge region of the target surface along the second direction extends to a side of the corresponding current collecting electrode electrically coupled to the end of the bus electrode segment adjacent to an edge region of the target surface along the second direction; and / or 8. The solar cell according to claim 1, wherein an end of the bus electrode segment adjacent to the first connection portion and an end of the first connection portion adjacent to the bus electrode segment are flat, or the end of the bus electrode segment adjacent to the first connection portion extends onto a portion of the first connection portion opposite to the cell substrate.

24. The solar cell according to any one of claims 1 to 23; and a soldering connection member for connecting adjacent solar cell strings, A solar module, characterized in that the solder connection member is soldered to the first connection portion and has an end face extending beyond the first connection portion.

25. the ratio of the length of the solder connection member beyond the first connection portion to the length of the bus electrode segment is 5% or more and 20% or less; or 25. The solar module according to claim 24, wherein the length of the bus electrode segment extending beyond the first connection portion is 2 mm or less.

26. 26. A solar module according to claim 24 or 25, wherein the soldered connection members and the bus electrode segments are in contact with each other or there is a gap between them.

27. Providing a solar cell according to any one of claims 1 to 23; and connecting adjacent solar cells in series with soldered connecting members using an infrared soldering process.

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