Back contact solar cell and photovoltaic module
Patent Information
- Application Number
- CN202521695017.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2026-09-22
- Estimated Expiration
- 2035-08-11
AI Technical Summary
但最靠近衬底边缘的边缘汇流栅线、以及与该边缘汇流栅线相交的边缘集电栅线容易出现印刷不良而造成断栅，进而影响边缘集电栅线与边缘汇流栅线之间的电流传输，背接触太阳电池的效率下降
[0029]本申请中，至少一根所述边缘集电栅线远离所述衬底中心的一端相交并凸出于所述边缘汇流栅线。也就是说，边缘汇流栅线与边缘集电栅线相交形成“十”字形结构或“X”形结构。如此一来，边缘集电栅线凸出边缘汇流栅线的部分增加了边缘集电栅线在第一方向上的连接位置，进而为边缘集电栅线的印刷提供了工程余量，即使边缘集电栅线印刷时在第一方向上发生偏移仍能够与边缘汇流栅线相交，进而有利于减少断栅现象。再者，边缘集电栅线能够在边缘汇流栅线与衬底边缘之间的区域进行电流收集，有利于提升边缘集电栅线的电流收集效果。
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Figure CN224791024U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of back-contact solar cell technology, and more particularly to a back-contact solar cell and photovoltaic module. Background Technology
[0002] To better collect current, back-contact solar cells also have busbars near the edge of their substrate. However, the edge busbars closest to the substrate edge, as well as the edge collector grids intersecting with these edge busbars, are prone to printing defects that can cause grid breaks. This can affect the current transfer between the edge collector grids and the edge busbars, leading to a decrease in the efficiency of the back-contact solar cell. Utility Model Content
[0003] This application discloses a back-contact solar cell and photovoltaic module, which can reduce grid breakage and has a wider extension area of the collector grid lines, resulting in better current collection and higher efficiency of the back-contact solar cell.
[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a back-contact solar cell, comprising:
[0005] A substrate having two substrate edges disposed opposite each other; the relative direction of the two substrate edges is a first direction, and the center of the substrate in the first direction is the substrate center;
[0006] Multiple busbars, each with two polarities, are alternately spaced along a first direction on the back side of the substrate, and each busbar extends along a second direction intersecting the first direction; and
[0007] Multiple collector gate lines are disposed on the back side of the substrate. The multiple collector gate lines are divided into two polarities. Each of the current collection gate lines intersects with several collector gate lines of the same polarity.
[0008] Among them, the multiple bus gate lines include two edge bus gate lines, each of the edge bus gate lines being the bus gate line closest to the edge of each of the substrates, the collector gate line intersecting with the edge bus gate line being the edge collector gate line, and at least one of the edge collector gate lines intersecting with and protruding from the edge bus gate line at one end away from the center of the substrate.
[0009] In a possible implementation of the first aspect, the distance between the edge collector gate line and the nearest edge of the substrate along the first direction is D1;
[0010] The substrate has a dimension D2 along the first direction;
[0011] Wherein, D2 / D1 = 120 to 4400.
[0012] In a possible implementation of the first aspect, the distance D1 between the edge collector gate line and the nearest edge of the substrate along the first direction is 0.05 mm to 1.5 mm;
[0013] And / or,
[0014] The substrate has a dimension D2 of 180 mm to 220 mm along the first direction.
[0015] In a possible implementation of the first aspect, the number of edge collector grids intersecting with each of the edge bus grids is multiple;
[0016] Along the second direction, the spacing between two adjacent edge collector lines on the same edge busbar is D3, and the dimension of the substrate along the second direction is D4; wherein, D4 / D3 = 16.6~500.
[0017] In one possible implementation of the first aspect, along the second direction, the spacing D3 between two adjacent edge collector lines on the same edge collector line is 0.5 mm to 3 mm;
[0018] And / or,
[0019] The substrate has a dimension D4 of 50 mm to 250 mm in the second direction.
[0020] In a possible implementation of the first aspect, along the first direction, the edge collector gate line further includes an inner segment, an intersecting segment, and an outer segment connected in sequence, the intersecting segment being located at the intersection of the edge collector gate line and the edge bus gate line, the inner segment being located on the side of the intersecting segment closer to the center of the substrate, and the outer segment being located on the side of the intersecting segment away from the center of the substrate;
[0021] Wherein, the length of the outer segment is L1, the length of the inner segment is L2, and L2 > L1.
[0022] In one possible implementation of the first aspect, the length L1 of the outer segment along the first direction is 0.01 mm to 1 mm.
[0023] In a possible implementation of the first aspect, the distance between the edge busbar and the nearest edge of the substrate along the first direction is D6;
[0024] The substrate has a dimension D2 along the first direction;
[0025] Among them, D2 / D6 = 72 to 3700.
[0026] In a possible implementation of the first aspect, the distance D6 between the edge busbar and the nearest edge of the substrate along the first direction is 0.06 mm to 2.5 mm.
[0027] Secondly, embodiments of this application disclose a photovoltaic module, including a plurality of electrically connected back-contact solar cells, at least one of which is the back-contact solar cell described in the first aspect.
[0028] Compared with the prior art, the beneficial effects of this application include at least the following:
[0029] In this application, at least one of the edge collector gate lines intersects and protrudes beyond the edge bus gate line at its end furthest from the center of the substrate. That is, the edge bus gate line intersects with the edge collector gate line to form a cross-shaped or X-shaped structure. This increases the number of connection points for the edge collector gate line in the first direction, thus providing engineering margin for the printing of the edge collector gate line. Even if the edge collector gate line is offset in the first direction during printing, it can still intersect with the edge bus gate line, thereby helping to reduce gate breakage. Furthermore, the edge collector gate line can collect current in the region between the edge bus gate line and the edge of the substrate, which helps to improve the current collection effect of the edge collector gate line.
[0030] In summary, the edge busbars and edge collector grids of this application exhibit fewer grid breakage phenomena, and the edge collector grids extend over a wider area, resulting in better current collection and higher conversion efficiency for the back-contact solar cells. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic diagram of the structure of a back-contact solar cell disclosed in an embodiment of this application;
[0033] Figure 2 This is a schematic diagram of the structure of a photovoltaic module disclosed in an embodiment of this application.
[0034] Explanation of reference numerals in the attached figures:
[0035] 10. Back contact solar cell; 11. Substrate; 111. Substrate edge; 112. Substrate center; 12. Busbar; 12a. Edge busbar; 13. Collector grid; 13a. Edge collector grid; 131. Inner section; 132. Intersecting section; 133. Outer section; Y, first direction; X, second direction;
[0036] 20. Welding strip. Detailed Implementation
[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0038] In this application, the terms "upper," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0039] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0040] Furthermore, the terms "set up," "equipped with," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0041] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.
[0042] The electrode structure of a back-contact solar cell includes busbars and collector grids, which intersect to enable current transfer. When the collector grids and busbars disconnect, i.e., when a grid break occurs, current cannot be transferred between them, thus affecting the performance of the back-contact solar cell.
[0043] The inventors discovered that edge busbars closest to the substrate edge are more prone to grid breakage. This is because, to reduce the transmission loss of the collector grid, the number of busbars is often relatively large. Since collector grids typically extend from two busbars, as the number of busbars increases, the spacing between them narrows, thus shortening the length of the collector grid and reducing its resistive loss. To accommodate more busbars on the back side of the back-contact solar cell, edge busbars are often placed closer to the substrate edge, with a spacing of less than 3 mm between the edge busbar and the substrate edge. In edge collector grids intersecting with edge busbars, the end of the edge collector grid furthest from the substrate center overlaps the edge busbar. This prevents the end of the edge collector grid from being too close to the substrate edge, thus avoiding the collector grid from being printed outside the substrate and causing contamination. However, when printing misalignment occurs, the end of the aforementioned edge collector grid is prone to printing abnormalities and breakage from the edge busbar, resulting in grid breakage.
[0044] Based on the above analysis, this application provides a back-contact solar cell, wherein at least one of the edge current collector lines intersects and protrudes beyond the edge busbar at its end furthest from the center of the substrate. That is, the edge busbar intersects with the edge current collector line to form a cross-shaped or X-shaped structure. In this way, the portion of the edge current collector line protruding beyond the edge busbar increases the number of connection points in the first direction. Even if the edge current collector line is offset in the first direction during printing, it can still intersect with the edge busbar, thereby helping to reduce the occurrence of broken grids.
[0045] The technical solution of this utility model will be described below with reference to the embodiments and accompanying drawings.
[0046] like Figure 1 As shown in the figure, this application discloses a back contact solar cell 10, including a substrate 11, multiple busbars 12 and multiple collector grids 13.
[0047] The substrate 11 has two substrate edges 111 disposed opposite to each other. The relative direction of the two substrate edges 111 is a first direction Y, and the center of the substrate 11 in the first direction Y is the substrate center 112.
[0048] Multiple busbars 12 are divided into two polarities. The two polarities of the busbars 12 are alternately arranged on the back side of the substrate 11 along the first direction Y, and each busbar 12 extends along the second direction X, which intersects the first direction Y.
[0049] Multiple collector gate lines 13 are disposed on the back side of the substrate 11. The multiple collector gate lines 13 are divided into two polarities. Each bus gate line 12 intersects with several collector gate lines 13 of the same polarity.
[0050] Among them, the multiple bus gate lines 12 include two edge bus gate lines 12a, each edge bus gate line 12a being the bus gate line 12 closest to each substrate edge 111, and the collector gate line 13 intersecting with the edge bus gate line 12a is the edge collector gate line 13a, and at least one edge collector gate line 13a intersects with and protrudes from the edge bus gate line 12a at one end away from the substrate center 112.
[0051] In this application, at least one edge collector gate line 13a intersects and protrudes beyond the edge bus gate line 12a at one end away from the substrate center 112. That is, at least one edge bus gate line 12a intersects with the edge collector gate line 13a to form a cross-shaped or X-shaped structure. In this way, the portion of the edge collector gate line 13a protruding beyond the edge bus gate line 12a increases the connection points of the edge collector gate line 13a in the first direction Y, thereby providing engineering margin for the printing of the edge collector gate line 13a. Even if the edge collector gate line 13a is offset to a certain extent in the first direction Y during printing, the edge collector gate line 13a can still intersect with the edge bus gate line 12a, thus helping to reduce gate breakage. Furthermore, the edge collector gate line 13a can collect current in the region between the edge bus gate line 12a and the substrate edge 111, which helps to improve the current collection effect of the edge collector gate line 13a.
[0052] In summary, the edge busbar 12a and edge collector grid 13a of this application have fewer grid breakage phenomena, and the edge collector grid 13a has a wider extension area, resulting in better current collection and higher conversion efficiency of the back contact solar cell 10.
[0053] It should be noted that the substrate 11 can be a silicon substrate. Two types of doped layers, namely N-type and P-type doped layers, are disposed on the back side of the substrate 11, spaced apart. These doped layers are, for example, doped polysilicon layers. A passivation film is also covered on the side of the doped layers facing away from the substrate 11. The passivation film is made of materials such as silicon oxide, silicon oxynitride, aluminum oxide, or silicon nitride. Two types of collector gate lines 13 penetrate the passivation film to form ohmic contacts with the corresponding doped layers. The bus gate lines are disposed on the side of the passivation film facing away from the doped layers.
[0054] More specifically, the two types of collector grid lines 13 refer to the positive collector grid line 13 and the negative collector grid line 13, respectively. Correspondingly, the two types of bus grid lines 12 refer to the positive bus grid line 12 and the negative bus grid line 12.
[0055] In some embodiments, along the first direction Y, the distance between the edge collector gate line 13a and the nearest substrate edge 111 is D1; the dimension of the substrate 11 along the first direction Y is D2; wherein, D2 / D1 = 120 to 4400, for example, 120, 500, 1000, 2000 or 4400.
[0056] In this embodiment, when D2 / D1 meets the aforementioned ratio range, it means that the edge collector gate line 13a is sufficiently close to the substrate edge 111. This is beneficial for expanding the current range of the edge collector gate line 13a and for forming an ohmic contact between the edge collector gate line 13a and the edge of the doped layer, thereby reducing the resistive loss during carrier transport at the edge of the doped layer. Furthermore, the edge collector gate line 13a is not too close to the substrate edge 111, reducing the risk of the edge collector gate line 13a being printed outside the substrate 111, thus avoiding printing contamination.
[0057] Optionally, along the first direction Y, the distance D1 between the edge collector gate line 13a and the nearest substrate edge 111 is 0.05 mm to 1.5 mm. When D1 meets the above distance range, the distance D1 between the edge collector gate line 13a and the substrate edge 111 is small enough, which is beneficial for expanding the current range of the edge collector gate line 13a and for forming an ohmic contact between the edge collector gate line 13a and the edge of the doped layer, thereby reducing the resistive loss during carrier transport at the edge of the doped layer. Furthermore, the edge collector gate line 13a is not too close to the substrate edge 111, reducing the risk of the edge collector gate line 13a being printed outside the substrate 111, thereby avoiding printing contamination.
[0058] Optionally, the dimension D2 of the substrate 11 along the first direction Y is 180mm to 220mm, for example, 180mm, 182mm, 210mm or 220mm. When the dimension D2 of the substrate 11 along the first direction Y meets the above-mentioned dimension range, the back contact solar cell 10 made based on the substrate 11 can effectively improve the power and power generation efficiency of the photovoltaic module.
[0059] In some embodiments, the number of edge collector gates 13a intersecting with each edge bus gate 12a is multiple; along the second direction X, the spacing between two adjacent edge collector gates 13a on the same edge bus gate 12a is D3, and the dimension of the substrate 11 along the second direction X is D4; wherein, D4 / D3 = 16.6 to 500, for example, 16.6, 100, 200, 300, 400 or 500.
[0060] In this embodiment, when D4 / D3 meets the above-mentioned ratio range, the spacing between two adjacent edge collector grid lines 13a is sufficiently close to shorten the carrier transmission path and reduce carrier transmission loss. Furthermore, the spacing between two adjacent edge collector grid lines 13a is not too close or too dense to avoid affecting the bifaciality of the back-contact solar cell 10. Additionally, the spacing of the printed holes of the collector grid lines 13 on the printing screen is also not too close to avoid reducing the edge structural strength of the printing screen.
[0061] Optionally, along the second direction X, the spacing D3 between two adjacent edge collector grids 13a on the same edge collector grid 12a is 0.5mm to 3mm, for example, 0.5mm, 1mm, 2mm, or 3mm. When D3 meets the above spacing range, the spacing between two adjacent edge collector grids 13a is close enough to shorten the transport path of charge carriers collected from the substrate to the edge collector grid 13a, thereby reducing the transport loss of charge carriers. Furthermore, the spacing between two adjacent edge collector grids 13a is not too close or too dense, so as not to affect the bifaciality of the back contact solar cell 10. Moreover, the spacing of the collector grid printing grooves on the printing screen is not too close, so as not to reduce the edge structural strength of the printing screen. In other words, a spacing D3 of 0.5mm to 3mm is also beneficial to improving the structural strength of the printing screen.
[0062] Optionally, the dimension D4 of the substrate 11 in the second direction X is 50 mm to 250 mm, for example, 50 mm, 91 mm, 105 mm, 210 mm or 250 mm. When the dimension D4 of the substrate 11 in the second direction X meets the above-mentioned dimension range, the back contact solar cell 10 made based on the substrate 11 can effectively improve the power and power generation efficiency of the photovoltaic module.
[0063] In some embodiments, along the first direction Y, the edge collector gate line 13a further includes an inner segment 131, an intersecting segment 132, and an outer segment 133 connected in sequence. The intersecting segment 132 is located at the intersection of the edge collector gate line 13a and the edge bus gate line 12a. The inner segment 131 is located on the side of the intersecting segment 132 closer to the substrate center 112, and the outer segment 133 is located on the side of the intersecting segment 132 away from the substrate center 112. The length of the outer segment 133 is L1, the length of the inner segment 131 is L2, and L2 > L1.
[0064] In other words, the inner segment 131 is longer than the outer segment 133, and the intersecting segment 132 is located at the end of the edge collector gate line 13a away from the center of the substrate 112. That is, the edge bus gate line 12a intersects at the end of the edge collector gate line 13a away from the center of the substrate 112. The edge bus gate line 12a is closer to the nearest substrate edge 111, so that more bus gate lines 12 can be arranged on the back side of the substrate 11 between the two edge bus gate lines 12a. The more bus gate lines 12 there are, the shorter the length of the collector gate line 13 on the bus gate line 12, which is more conducive to the resistance loss during carrier transport.
[0065] Optionally, along the first direction Y, the length L1 of the outer segment 133 is 0.01 mm to 1 mm. When the length L1 of the outer segment 133 meets the above-mentioned length range, the length L1 of the outer segment 133 is long enough to provide sufficient engineering margin for the printing offset of the edge collector gate line 13a. Furthermore, the outer segment 133 is not too long to avoid printing it outside the substrate 11, causing contamination and edge leakage.
[0066] In some embodiments, along the first direction Y, the distance between the edge bus gate 12a and the nearest substrate edge 111 is D6; wherein D2 / D6 = 72 to 3700, for example, 72, 100, 500, 1000, 2000, or 3700. When D2 / D6 meets the above ratio range, the distance between the edge bus gate 12a and the nearest substrate edge 111 is close enough to expand the current collection range of the edge collector gate 13a, making the current collection range of the edge collector gate 13a as close as possible to the substrate edge 111. Furthermore, the distance between the edge bus gate 12a and the nearest substrate edge 111 is not too close to reduce the risk of the edge bus gate 12a being printed outside the substrate 11 when printing misalignment occurs.
[0067] Optionally, along the first direction Y, the distance D6 between the edge busbar 12a and the nearest substrate edge 111 is 0.06 mm to 2.5 mm, for example, 0.06 mm, 0.1 mm, 1 mm, 2 mm, or 2.5 mm. When the distance D6 between the edge busbar 12a and the nearest substrate edge 111 meets the above-mentioned spacing range, the distance between the edge busbar 12a and the nearest substrate edge 111 is close enough to expand the current collection range of the edge collector gate 13a, making the current collection range of the edge collector gate 13a as close as possible to the substrate edge 111. Furthermore, the distance between the edge busbar 12a and the nearest substrate edge 111 is not too close to reduce the risk of the edge busbar 12a being printed outside the substrate 11 when printing misalignment occurs.
[0068] Reference Figure 2This application also discloses a photovoltaic module, including a plurality of electrically connected back contact solar cells 10, at least one of the back contact solar cells 10 being the back contact solar cell 10 disclosed in this application.
[0069] Specifically, the back contact solar cells 10 can be electrically connected in parallel and / or in series. More specifically, the back contact solar cells 10 can be electrically connected via solder strips 20.
[0070] As analyzed above, in this back-contact solar cell 10, there are fewer grid breaks in the edge busbar 12a and the edge collector grid 13a, and the extension area of the edge collector grid 13a is wider, resulting in better current collection and higher conversion efficiency of the back-contact solar cell 10, which in turn helps to improve the conversion efficiency of the photovoltaic module.
[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A back-contact solar cell, characterized in that, include: A substrate having two substrate edges disposed opposite to each other; The relative direction of the two substrate edges is a first direction, and the center of the substrate in the first direction is the substrate center; Multiple busbars, each of which has two polarities, are alternately spaced on the back side of the substrate along the first direction, and each of the busbars extends along a second direction that intersects the first direction. as well as Multiple collector gate lines are disposed on the back side of the substrate. The multiple collector gate lines are divided into two polarities. Each of the current collection gate lines intersects with several collector gate lines of the same polarity. Among them, the multiple bus gate lines include two edge bus gate lines, each of the edge bus gate lines being the bus gate line closest to the edge of each of the substrates, the collector gate line intersecting with the edge bus gate line being the edge collector gate line, and at least one of the edge collector gate lines intersecting with and protruding from the edge bus gate line at one end away from the center of the substrate.
2. The back-contact solar cell according to claim 1, characterized in that, Along the first direction, the distance between the edge collector gate line and the nearest edge of the substrate is D1; The substrate has a dimension D2 along the first direction; Wherein, D2 / D1 = 120 to 4400.
3. The back-contact solar cell according to claim 2, characterized in that, Along the first direction, the distance D1 between the edge collector gate line and the nearest edge of the substrate is 0.05 mm to 1.5 mm; And / or, The substrate has a dimension D2 of 180 mm to 220 mm along the first direction.
4. The back-contact solar cell according to claim 1, characterized in that, The number of edge collector grids intersecting with each of the aforementioned edge busbars is multiple; Along the second direction, the spacing between two adjacent edge collector lines on the same edge busbar is D3, and the dimension of the substrate along the second direction is D4; wherein, D4 / D3 = 16.6~500.
5. The back-contact solar cell according to claim 4, characterized in that, Along the second direction, the spacing D3 between two adjacent edge collector lines on the same edge collector line is 0.5mm to 3mm; And / or, The substrate has a dimension D4 of 50 mm to 250 mm in the second direction.
6. The back-contact solar cell according to claim 1, characterized in that, Along the first direction, the edge collector gate line further includes an inner section, an intersecting section, and an outer section connected in sequence. The intersecting section is located at the intersection of the edge collector gate line and the edge bus gate line. The inner section is located on the side of the intersecting section closer to the center of the substrate, and the outer section is located on the side of the intersecting section away from the center of the substrate. Wherein, the length of the outer segment is L1, the length of the inner segment is L2, and L2 > L1.
7. The back-contact solar cell according to claim 6, characterized in that, Along the first direction, the length L1 of the outer segment is 0.01 mm to 1 mm.
8. The back-contact solar cell according to any one of claims 1 to 7, characterized in that, Along the first direction, the distance between the edge busbar and the nearest edge of the substrate is D6; The substrate has a dimension D2 along the first direction; Among them, D2 / D6 = 72 to 3700.
9. The back-contact solar cell according to claim 8, characterized in that, Along the first direction, the distance D6 between the edge busbar and the nearest edge of the substrate is 0.06 mm to 2.5 mm.
10. A photovoltaic module, characterized in that, It includes several electrically connected back-contact solar cells, at least one of which is a back-contact solar cell according to any one of claims 1 to 9.