Photovoltaic cell and photovoltaic module

Abstract

The invention provides a photovoltaic cell and a photovoltaic module. The photovoltaic cell comprises a substrate; the doping layer and the passivation layer are arranged on the substrate; a first contact electrode passing through the passivation layer and in contact with the doping layer; and the first transmission electrode is connected with the first contact electrode. The first transmission electrode is used for interconnection between two adjacent photovoltaic cells. The first transmission electrode comprises a non-interconnection end, and the first contact electrode comprises a first end part closest to the non-interconnection end; the length of the first transmission electrode between the first end portion and the end point of the non-interconnection end is W2, the length from the first end portion to the corresponding edge of the substrate in the third direction is W1, and W2 is larger than W1. W2 is greater than W1, so that the part, exceeding the first end part, of the first transmission electrode has enough length, and the electrical contact between the first transmission electrode and the first end part can be effectively ensured, thereby improving the connection strength between the first transmission electrode and the first contact electrode, reducing the occurrence of electric leakage, and improving the yield and performance of the battery.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic cell manufacturing technology, and in particular, relates to a photovoltaic cell and a photovoltaic module. Background Art

[0002] At present, the crystalline silicon photovoltaic cell (also known as solar cell) industry is becoming more and more perfect. As the cost of electricity from solar cells is getting lower and lower, the cost of precious metal materials used in solar cells is becoming higher and higher. In this case, it is becoming more and more important to use other alternative materials to replace part or all of the metal electrodes.

[0003] Point contact technology is a very feasible electrode technology, which is formed by preparing a doping layer and a passivation layer on a substrate; preparing a contact electrode on the passivation layer so that the contact electrode passes through the passivation layer and is in electrical contact with the doping layer; and preparing a transmission electrode on the contact electrode, so that the transmission electrode is in electrical contact with the doping layer on the substrate through the contact electrode to form a solar cell. Such a cell structure can use extremely low-cost metals or other materials as transmission electrodes; and because the electrical contact area between the contact electrode and the doping layer on the substrate is small, it can also effectively avoid surface carrier recombination caused by large-area metal contact, thereby improving cell performance. However, if the transmission electrode is too close to the edgemost contact electrode, it will affect the electrical contact between the transmission electrode and the edgemost contact electrode, thereby weakening the overall performance of the solar cell. Summary of the invention

[0004] The present application provides a photovoltaic cell and a photovoltaic module to solve the technical problem that the electrical contact between the transmission electrode and the edgemost contact electrode of the existing photovoltaic cell is unstable, which affects the cell performance.

[0005] According to one aspect of the present application, a photovoltaic cell is provided, which includes: a substrate, wherein the direction perpendicular to the substrate is a first direction, and the two directions perpendicular to the first direction and mutually perpendicular are a second direction and a third direction respectively; a doping layer and a passivation layer stacked in sequence on the first surface of the substrate; a first contact electrode, which passes through the passivation layer and contacts the doping layer; a first transmission electrode, which is located on the first contact electrode and is electrically connected to the first contact electrode. The first contact electrode and the first transmission electrode located thereon both extend along the third direction, and the first transmission electrode is used for interconnection between two adjacent photovoltaic cells. Wherein, the first transmission electrode includes a non-interconnected end, and the first contact electrode includes a first end closest to the non-interconnected end; the length of the first transmission electrode between the first end and the end point of the non-interconnected end is W2, and the length from the first end to the corresponding edge of the substrate in the third direction is W1, and W2>W1.

[0006] In an optional solution of the present application, W2>0.5mm.

[0007] In an optional solution of the present application, W2<5mm.

[0008] In an optional solution of the present application, W1>0.3mm.

[0009] In an optional solution of the present application, the first transmission electrode includes a first portion and a second portion at the non-interconnected end extending away from the first portion.

[0010] In an optional solution of the present application, the deviation distance of the second part from the first part is W3, and W3≥0.05mm.

[0011] In the optional solution of the present application, preferably, W3 ≥ 0.1 mm.

[0012] In an optional solution of the present application, the length of the orthographic projection of the second portion on the substrate in the third direction is W4, and W4<W1.

[0013] In an optional solution of the present application, W4 satisfies 0.01≤W4≤5mm.

[0014] In an optional solution of the present application, the photovoltaic cell further comprises a second contact electrode and a second transmission electrode arranged on a second surface of the substrate opposite to the first surface, wherein the second transmission electrode is an opposite electrode symmetrically arranged with respect to the substrate with respect to the first transmission electrode.

[0015] In an optional solution of the present application, the photovoltaic cell further comprises a second contact electrode and a second transmission electrode arranged on a second surface of the substrate opposite to the first surface, wherein the second transmission electrode is an opposite electrode arranged alternately with the first transmission electrode relative to the substrate.

[0016] In an optional solution of the present application, the photovoltaic cell further includes a second contact electrode and a second transmission electrode disposed on the first surface, wherein the second transmission electrode is an electrode of opposite polarity adjacent to the first transmission electrode.

[0017] In an optional solution of the present application, a distance from the lowest point of the free end of the second portion to the highest point of the corresponding end of the second transmission electrode in the second direction is W5, and 0.01≤W5≤1.5 mm.

[0018] In an optional solution of the present application, an end portion of the second transmission electrode corresponding to the non-interconnected end of the first transmission electrode extends beyond an edge of the substrate.

[0019] In an optional solution of the present application, a length of a portion of the end portion extending beyond the edge of the substrate in the third direction is W6, and 0.01≤W6≤5 mm.

[0020] In an optional solution of the present application, at least one of the first contact electrodes is a discontinuous structure; the discontinuous structure includes a plurality of sub-first contact electrodes arranged at intervals, and the plurality of sub-first contact electrodes are electrically connected to the corresponding first transmission electrodes at the same time.

[0021] In an optional solution of the present application, the length of the sub-first contact electrode in the second direction is 0.02-0.2 mm, and the length in the third direction is 0.02-5 mm.

[0022] According to another aspect of the present application, a photovoltaic assembly is provided, which includes: a plurality of photovoltaic cells as described above, wherein two adjacent photovoltaic cells are interconnected via the first transmission electrode.

[0023] In an optional solution of the present application, at least two adjacent photovoltaic cells partially overlap.

[0024] In summary, the photovoltaic cell and photovoltaic module provided by the present application have at least the following beneficial effects:

[0025] In the present application, by arranging a doping layer and a passivation layer on the substrate, and passing the first contact electrode through the passivation layer and electrically contacting the doping layer, and arranging a first transmission electrode electrically connected to the first contact electrode, the current collection and conduction from the doping layer to the first contact electrode to the first transmission electrode is realized. Based on such a photovoltaic cell structure, metal or other materials with extremely low cost can be used as the first contact electrode and the first transmission electrode, thereby saving the cost of the photovoltaic cell. In addition, since W2>W1, it is equivalent to arranging the first transmission electrode beyond the first contact electrode on the side of the non-interconnected end of the first transmission electrode in the third direction, and setting the length of the portion of the first transmission electrode beyond the first end of the first contact electrode to be greater than the length of the first end to the corresponding edge of the substrate in the third direction, so that the portion of the first transmission electrode beyond the first end of the first contact electrode has sufficient length, which can effectively ensure the electrical contact between the first transmission electrode and the first end of the first contact electrode, thereby improving the connection strength between the first transmission electrode and the first contact electrode and the current collection capacity of the first transmission electrode, thereby reducing the occurrence of leakage and improving the yield and performance of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic diagram of the connection relationship of several photovoltaic cells of a photovoltaic assembly provided in an embodiment of the present application;

[0028] Figure 2 A schematic diagram of a side-by-side arrangement of adjacent photovoltaic cells of a photovoltaic module provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of side-by-side arrangement of adjacent photovoltaic cells of another photovoltaic assembly provided in an embodiment of the present application;

[0030] Figure 4 A schematic diagram of overlapping arrangement of adjacent photovoltaic cells at the ends of a photovoltaic module provided in an embodiment of the present application;

[0031] Figure 5 A schematic diagram of overlapping arrangement of adjacent photovoltaic cells at the ends of another photovoltaic assembly provided in an embodiment of the present application;

[0032] Figure 6 A schematic cross-sectional view of a photovoltaic cell provided in an embodiment of the present application;

[0033] Figure 7 A cross-sectional schematic diagram of another photovoltaic cell provided in an embodiment of the present application;

[0034] Figure 8 A schematic diagram of the connection relationship between adjacent photovoltaic cells of a photovoltaic module provided in an embodiment of the present application;

[0035] Fig. 9 A schematic diagram of the connection relationship between adjacent photovoltaic cells of another photovoltaic assembly provided in an embodiment of the present application;

[0036] Fig.10 This is a perspective view of a photovoltaic cell provided in an embodiment of the present application.

[0037] The reference numerals are as follows:

[0038] 1000. Photovoltaic modules;

[0039] 100. Photovoltaic cells;

[0040] 10. substrate; 20. doping layer; 30. passivation layer; 40. first contact electrode; 41. sub-first contact electrode;

[0041] 50, first transmission electrode; 51, first portion; 52, second portion; 60, second contact electrode; 70, second transmission electrode;

[0042] L1, first direction; L2, second direction; L3, third direction. DETAILED DESCRIPTION

[0043] In order to make the above and other features and advantages of the present application more clear, the present invention is further described below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given herein are for the purpose of explaining to those skilled in the art and are only exemplary and not restrictive.

[0044] In the description of this application, if there is a feature defined as "first" or "second" for descriptive purposes only, it cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Features defined as "first" or "second" may explicitly or implicitly include at least one of the defined features. If the description of "plurality" appears, the general meaning is to include at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In this application, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and so on should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection, it can be a direct connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0046] In the description of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0047] Figure 1This is a schematic diagram of the connection relationship of several photovoltaic cells of a photovoltaic assembly provided in an embodiment of the present application.

[0048] See also Figure 1 The photovoltaic module 1000 provided in the present application includes a plurality of photovoltaic cells 100, which can be connected into a plurality of cell strings, and the plurality of cell strings can output current by connecting in series, in parallel, or in a combination of series and parallel. The plurality of photovoltaic cells 100 in each cell string are connected in series in sequence to form a cell string.

[0049] For example, Figure 1 As shown, the photovoltaic assembly 1000 includes two cell strings arranged along the second direction L2, and the six photovoltaic cells 100 in each cell string are arranged in sequence along the third direction L3.

[0050] The interconnection between two adjacent photovoltaic cells 100 in each cell string can be realized by using an additional conductive structure, for example, by providing a metal conductive layer, a circuit substrate, a conductive adhesive, etc. between the connection parts of the two. Furthermore, in order to protect the photovoltaic cell 100, the photovoltaic module 1000 can also include a packaging film located outside the photovoltaic cell 100.

[0051] It should be noted that the first direction L1 herein is a direction perpendicular to the photovoltaic cell 100 (also referred to as the thickness direction of the photovoltaic cell 100), and the two directions perpendicular to the first direction L1 and perpendicular to each other are the second direction L2 and the third direction L3. Among them, the second direction L2 can be the length direction of the photovoltaic cell 100, and the third direction L3 is the width direction of the photovoltaic cell 100; of course, the second direction L2 can also be the width direction of the photovoltaic cell 100, and the third direction L3 is the length direction of the photovoltaic cell 100, which is not specifically limited in this application.

[0052] Figure 2 This is a schematic diagram of adjacent photovoltaic cells of a photovoltaic module provided in an embodiment of the present application arranged side by side. Figure 3 This is a schematic diagram of the side-by-side arrangement of adjacent photovoltaic cells of another photovoltaic assembly provided in an embodiment of the present application.

[0053] See also Figure 2 and Figure 3 In the photovoltaic module 1000, at least two adjacent photovoltaic cells 100 may be arranged side by side and interconnected. Specifically, in this embodiment, the photovoltaic cell 100 may be a back contact cell, such as Figure 2 As shown; the photovoltaic cell 100 can also be a double-sided cell, such as Figure 3 shown.

[0054] In the present application, two adjacent photovoltaic cells 100 are directly arranged side by side, which is simple and convenient and helps to improve the connection efficiency between the photovoltaic cells 100 .

[0055] Figure 4 This is a schematic diagram of overlapping arrangement of adjacent photovoltaic cells of a photovoltaic module provided in an embodiment of the present application at the ends. Figure 5 This is a schematic diagram of overlapping arrangement of adjacent photovoltaic cells at the ends of another photovoltaic assembly provided in an embodiment of the present application.

[0056] See also Figure 4 and Figure 5 In the photovoltaic module 1000, at least two adjacent photovoltaic cells 100 may be arranged to overlap at the end portions. Specifically, in this embodiment, the photovoltaic cell 100 may be a back contact cell, such as Figure 4 As shown; the photovoltaic cell 100 can also be a double-sided cell, such as Figure 5 shown.

[0057] In the present application, two adjacent photovoltaic cells 100 are directly arranged to be partially overlapped, which can not only reduce stress, but also avoid the mutual crowding problem caused by the connection parts of adjacent photovoltaic cells 100 being on the same straight line, thereby improving the yield of photovoltaic modules and reducing stress.

[0058] Figure 6 is a cross-sectional schematic diagram of a photovoltaic cell provided in an embodiment of the present application, Figure 7 This is a cross-sectional schematic diagram of another photovoltaic cell provided in an embodiment of the present application.

[0059] See also Figure 6 and Figure 7 The photovoltaic cell 100 includes a substrate 10 , a doping layer 20 , a passivation layer 30 , a first contact electrode 40 and a first transmission electrode 50 .

[0060] In the first direction L1, the substrate 10 includes a first surface and a second surface opposite to each other, that is, the thickness direction of the substrate 10 is the first direction L1. Figure 6 and Figure 7 As shown, the first surface of the substrate 10 may be the upper surface of the substrate 10 or the lower surface of the substrate 10. The substrate 10 in the present application may be a p-type silicon substrate, an n-type silicon substrate, or a silicon substrate close to the intrinsic conductivity type. The crystal type may be single crystal or polycrystalline.

[0061] Specifically, the doping layer 20 may be disposed only on the first surface of the substrate 10, or may be disposed on both the first surface and the second surface of the substrate 10. Wherein, when the doping layer 20 is disposed on the first surface and the second surface of the substrate 10, the doping type of the doping layer 20 located on the first surface of the substrate 10 and the doping type of the doping layer 20 located on the second surface of the substrate 10 may be different, one of which is n-type doping and the other is p-type doping. The doping layer 20 may be composed of one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon. Specifically, the p-type doping layer is generally doped with group III elements, and the n-type doping layer is generally doped with group V elements or group VI elements.

[0062] The passivation layer 30 is disposed on the doped layer 20, and may be a single layer or a multilayer structure, or may be composed of different materials in different regions. The material of the passivation layer 30 may include: one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. An opening (or opening) is provided in the passivation layer 30, and the opening is used to accommodate the first contact electrode 40, so that the first contact electrode 40 can be in electrical contact with the doped layer 20.

[0063] It can be understood that different types of photovoltaic cells 100 can be formed based on the doping layer 20 and the passivation layer 30 being stacked on different surfaces of the substrate 10. Specifically, when the doping layer 20 and the passivation layer 30 are stacked on the first surface and the second surface of the substrate 10 (that is, the doping layer 20 and the passivation layer 30 are both provided on the upper and lower surfaces of the substrate 10), the formed photovoltaic cell 100 is a bifacial cell, such as Figure 6 As shown; when the doping layer 20 and the passivation layer 30 are only sequentially stacked on the first surface of the substrate 10 (that is, the doping layer 20 and the passivation layer 30 are only provided on one side of the substrate 10), the formed photovoltaic cell 100 is a back contact cell, such as Figure 7 shown.

[0064] The first contact electrode 40 passes through the passivation layer 30 through the opening on the passivation layer 30 to electrically contact the doping layer 20. The first transmission electrode 50 is located on the first contact electrode 40 and is electrically connected to the first contact electrode 40, thereby realizing current collection and conduction from the doping layer 20 to the first contact electrode 40 to the first transmission electrode 50.

[0065] The first contact electrode 40 and the first transmission electrode 50 located thereon both extend along the third direction L3. The first contact electrode 40 may be a strip-shaped structure extending along the third direction L3, or may be a discontinuous structure extending along the third direction L3 (eg, Figure 7 As shown), the first transmission electrode 50 is connected to each part of the discontinuous structure.

[0066] In the photovoltaic module 1000, two adjacent photovoltaic cells 100 can be directly interconnected through the first transmission electrode 50. Compared with separately setting a conductive interconnection member (such as a traditional welding strip) on the surface of the entire photovoltaic cell 100, the process of interconnecting through the first transmission electrode 50 in the present application is simpler and has lower cost.

[0067] Specifically, the first transmission electrode 50 includes an interconnection end and a non-interconnection end, and two adjacent photovoltaic cells 100 are interconnected through the interconnection end of the first transmission electrode 50. Among them, the two adjacent photovoltaic cells 100 can be interconnected in the second direction L2 or in the third direction L3, which is not specifically limited in this application.

[0068] In a photovoltaic cell 100, the "interconnection end" refers to an end of the first transmission electrode 50 of the photovoltaic cell 100 used to interconnect with an adjacent photovoltaic cell 100, such as Figure 7 and the "non-interconnected end" refers to the end of the first transmission electrode 50 of the photovoltaic cell 100 that is not interconnected with the adjacent photovoltaic cell 100, such as Figure 7 The right end of .

[0069] See also Figure 7 The first contact electrode 40 includes a first end portion closest to the non-interconnected end, a length of the first transmission electrode 50 between the first end portion and an end point of the non-interconnected end is W2, a length from the first end portion to a corresponding edge of the substrate 10 in the third direction L3 is W1, and W2>W1.

[0070] It should be noted that the “first end” refers to the portion of the first contact electrode 40 that is closest to the edge of the battery and connected to the first transmission electrode 50; and the “length of the first transmission electrode 50 between the first end and the endpoint of the non-interconnected end” refers to the physical length of the portion, rather than the absolute length in the third direction L3.

[0071] For example, when the corresponding portion of the first transmission electrode 50 between the first end and the endpoint of the non-interconnected end is a flat plate structure, the physical length of the portion is consistent with its absolute length in the third direction L3, and in this case, the portion must be set beyond the corresponding edge of the substrate 10; and when the corresponding portion of the first transmission electrode 50 between the first end and the endpoint of the non-interconnected end is a structure with a bent portion, the physical length of the portion is the sum of the lengths of each portion in their respective extension directions, and the physical length of the portion is greater than its absolute length as a whole in the third direction L3, and in this case, the portion may be set beyond the corresponding edge of the substrate 10 or may not be set beyond the corresponding edge of the substrate 10.

[0072] It can be understood that the first contact electrode 40 and the first transmission electrode 50 in the present application can be electrodes of positive polarity or electrodes of negative polarity.

[0073] Specifically, the first contact electrode 40 and the first transmission electrode 50 can both use metals (such as Ag, Cu, Al, Ni, Au, Zn, Sn, Pb, etc.), metal oxides (various TCOs, such as ITO, AZO, IWO, etc.), metal nitrides (TiN, etc.), metal carbides (TiC, etc.) or metal sulfides, and other conductive connection materials (such as graphene, etc.), or various combinations of the above materials. Preferably, the first transmission electrode 50 is made of base metals, such as Al, Cu, etc., and other cheap metals based on aluminum and / or copper.

[0074] In the present application, by arranging the doping layer 20 and the passivation layer 30 on the substrate 10, and the first contact electrode 40 passing through the passivation layer 30 and electrically contacting the doping layer 20, and arranging the first transmission electrode 50 electrically connected to the first contact electrode 40, the current collection and conduction from the doping layer 20 to the first contact electrode 40 to the first transmission electrode 50 is realized. Based on such a photovoltaic cell 100 structure, extremely low-cost metals or other materials can be used as the first contact electrode 40 and the first transmission electrode 50, thereby saving the cost of the photovoltaic cell 100.

[0075] Furthermore, since W2>W1, it is equivalent to setting the first transmission electrode 50 beyond the first contact electrode 40 and setting the length of the portion of the first transmission electrode 50 beyond the first end of the first contact electrode 40 to be greater than the length from the first end to the corresponding edge of the substrate 10 in the third direction L3 on the side of the non-interconnected end of the first transmission electrode 50 in the third direction L3, so that the portion of the first transmission electrode 50 beyond the first end of the first contact electrode 40 has a sufficient length, which can effectively ensure the electrical contact between the first transmission electrode 50 and the first end of the first contact electrode 40, thereby improving the connection strength between the first transmission electrode 50 and the first contact electrode 40 and the current collection capacity of the first transmission electrode 50, thereby reducing the occurrence of leakage and improving the yield and performance of the photovoltaic cell 100.

[0076] In some embodiments, W2>0.5mm. For example, W2 may be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, etc. In this way, it is ensured that the portion of the first transmission electrode 50 that exceeds the first end of the first contact electrode 40 has a sufficient length, which can effectively ensure the electrical contact between the first transmission electrode 50 and the first end of the first contact electrode 40, thereby improving the connection strength between the first transmission electrode 50 and the first contact electrode 40 and the current collection capacity of the first transmission electrode 50, thereby reducing leakage and improving the yield and performance of the photovoltaic cell 100.

[0077] In some embodiments, W2 is less than 5 mm. For example, W2 may be 0.6 mm, 0.8 mm, 1.2 mm, 1.5 mm, 2.2 mm, 2.5 mm, 3.5 mm, 4.5 mm, 4.8 mm, etc. This arrangement ensures that the actual length of the first transmission electrode 50 extending beyond the first end of the first contact electrode 40 is not too long, thereby preventing the passivation layer 30 of the adjacent photovoltaic cell 100 from being damaged by the first transmission electrode 50 due to excessive length of W2, and preventing the extending portion of the first transmission electrode 50 corresponding to W2 from swinging back and forth during the subsequent production process of the photovoltaic cell 100 and the photovoltaic module, thereby preventing the short circuit problem.

[0078] In some embodiments, W1>0.3mm. For example, W1 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 6mm, 7mm, 8mm, etc.

[0079] It should be noted that in order to achieve electrical contact between the first contact electrode 40 and the doping layer 20, laser opening is usually used to set an opening (or hole) in the passivation layer 30. During the laser opening process, local heat will be applied to the photovoltaic cell 100. This heat will form thermal stress concentration on the surface of the cell, making the cell prone to fragmentation and hidden cracks. If the opening position is too close to the edge of the cell, the risk of fragmentation and hidden cracks in the cell will be aggravated.

[0080] Therefore, the present application sets W1 within the above range to ensure that the opening position on the passivation layer 30 corresponding to the first end of the first contact electrode 40 is not too close to the corresponding edge of the substrate 10, but has a sufficient distance, thereby effectively reducing the stress concentration on the battery surface and reducing the probability of battery damage, thereby reducing the safety risks during the use of the photovoltaic cell 100.

[0081] Figure 8 Schematic diagram of the connection relationship between adjacent photovoltaic cells of a photovoltaic module provided in an embodiment of the present application, Fig. 9 A schematic diagram of the connection relationship between adjacent photovoltaic cells of another photovoltaic assembly provided in an embodiment of the present application.

[0082] See also Figure 8 and Fig. 9 , the first transmission electrode 50 includes a first portion 51 and a second portion 52 at the non-interconnected end extending away from the first portion 51. That is, the second portion 52 is located at the non-interconnected end, and at least a portion of the second portion 52 extends in a direction different from that of the first portion 51, so that the second portion 52 is arranged away from the first portion 51. Exemplarily, when the photovoltaic cells 100 are interconnected along the third direction L3, the first portion 51 extends along the third direction L3, and the second portion 52 extends obliquely relative to the third direction L3.

[0083] The portion of the first transmission electrode 50 corresponding to W2 may be disposed beyond the corresponding edge of the substrate 10 or may not be disposed beyond the corresponding edge of the substrate 10. Specifically, when the portion of the first transmission electrode 50 corresponding to W2 is a portion of the second portion 52, W2 is the extension length of the corresponding portion of the second portion 52; when the portion of the first transmission electrode 50 corresponding to W2 is the entire second portion 52, W2 is the extension length of the second portion 52; when the portion of the first transmission electrode 50 corresponding to W2 includes the second portion 52 and a portion of the first portion 51, W2 is the sum of the extension length of the portion of the first portion 51 and the extension length of the second portion 52.

[0084] In the third direction L3, since the second portion 52 is located on the non-interconnected end side of the first transmission electrode 50 and the second portion 52 is arranged to deviate from the first portion 51, it is equivalent to that at least a portion of the first transmission electrode 50 located at the non-interconnected end (that is, at least a portion of the portion of the first transmission electrode 50 corresponding to W2) is bent. The bending can prevent the non-interconnected end of the first transmission electrode 50 from contacting the first transmission electrode 50 of the adjacent photovoltaic cell 100, thereby avoiding the occurrence of a short circuit.

[0085] In some embodiments, the deviation distance of the second portion 52 from the first portion 51 is W3, W3 ≥ 0.05 mm. For example, W3 may be 0.05 mm, 0.055 mm, 0.06 mm, 0.065 mm, 0.07 mm, 0.075 mm, 0.08 mm, 0.085 mm, 0.09 mm, 0.095 mm, 0.1 mm, etc. The "deviation distance W3" here refers to the distance between the second portion 52 and the first portion 51 at the maximum deviation.

[0086] When a plurality of photovoltaic cells 100 are connected in series to form a cell string, for two adjacent photovoltaic cells 100, the portion of the first transmission electrode 50 corresponding to W2 of one photovoltaic cell 100 cannot contact the first transmission electrode 50 of the other photovoltaic cell 100. Therefore, in the present application, the second portion 52 is set to deviate from the first portion 51 and the deviation distance W3 therebetween is set within the above range, which can provide an avoidance space for the first transmission electrodes 50 of adjacent photovoltaic cells 100, thereby preventing the portion of the first transmission electrode 50 corresponding to W2 from contacting the first transmission electrode 50 of the adjacent photovoltaic cell 100, thereby avoiding the occurrence of a short circuit.

[0087] Preferably, W3 ≥ 0.1 mm. For example, W3 may be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.7 mm, etc. In this way, a sufficiently large avoidance space can be provided for the first transmission electrodes 50 of the adjacent photovoltaic cells 100, even if the width of the first transmission electrodes 50 of the adjacent photovoltaic cells 100 (e.g. Figure 8 and Fig. 9 As shown, when the width of the first transmission electrode 50 refers to the size of the first transmission electrode 50 in the second direction L2) is wider, it can also prevent the part of the first transmission electrode 50 corresponding to W2 from contacting the first transmission electrode 50 of the adjacent photovoltaic cell 100, thereby not only avoiding the occurrence of short circuit, but also adapting to the first transmission electrode 50 with a larger width.

[0088] In some embodiments, please refer to Figure 8 and Fig. 9 , the length of the orthographic projection of the second portion 52 of the first transfer electrode 50 on the substrate 10 in the third direction L3 is W4, and W4<W1.

[0089] Since W4 is less than W1, the bending connection (i.e., the bending portion) between the second portion 52 and the first portion 51 of the first transmission electrode 50 is located between the first end portion of the first contact electrode 40 and the corresponding edge of the substrate 10. In this case, the first end portion of the first contact electrode 40 is connected to the first portion 51 instead of the second portion 52, so that the entire first end portion can be connected to the first transmission electrode 50, thereby ensuring good electrical contact between the first end portion of the first contact electrode 40 and the first transmission electrode 50, thereby improving the current collection capability of the first transmission electrode 50.

[0090] In some embodiments, 0.01≤W4≤5mm. For example, W4 may be 0.01mm, 0.1mm, 0.5mm, 0.6mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc. This arrangement can further ensure good electrical contact between the first end of the first contact electrode 40 and the first transmission electrode 50, thereby further improving the current collection capability of the first transmission electrode 50.

[0091] Please continue reading Figure 6 , Figure 8 and Fig. 9The photovoltaic cell 100 further includes a second contact electrode 60 and a second transmission electrode 70 disposed on the substrate 10. The second transmission electrode 70 is an opposite electrode having a different polarity from the first transmission electrode 50. Exemplarily, when the first contact electrode 40 and the first transmission electrode 50 are electrodes of positive polarity, the second contact electrode 60 and the second transmission electrode 70 are electrodes of negative polarity; conversely, when the first contact electrode 40 and the first transmission electrode 50 are electrodes of negative polarity, the second contact electrode 60 and the second transmission electrode 70 are electrodes of positive polarity.

[0092] It can be understood that the structure of the second transmission electrode 70 can be the same as that of the first transmission electrode 50, and the structure of the second contact electrode 60 can be the same as that of the first contact electrode 40, and the specific structures of the second transmission electrode 70 and the second contact electrode 60 are not repeated here.

[0093] See also Figure 6 and Figure 8 The photovoltaic cell 100 is a bifacial cell, and a doping layer 20 and a passivation layer 30 are disposed on both the first surface and the second surface of the substrate 10. On the first surface side, the first contact electrode 40 passes through the passivation layer 30 corresponding to the first surface to electrically contact the doping layer 20 corresponding to it, and the first transmission electrode 50 is located on the first contact electrode 40 and electrically connected to the first contact electrode 40, so as to realize the current collection and conduction from the doping layer 20 of the corresponding polarity to the first contact electrode 40 to the first transmission electrode 50 on the first surface side.

[0094] On the second surface side, the second contact electrode 60 passes through the passivation layer 30 corresponding to the second surface to electrically contact the doping layer 20 corresponding to it, and the second transmission electrode 70 is located on the second contact electrode 60 and electrically contacts the second contact electrode 60, thereby realizing current collection and conduction from the doping layer 20 of corresponding polarity to the second contact electrode 60 to the second transmission electrode 70 on the second surface side.

[0095] Specifically, in an embodiment not shown, in the first direction L1 , the second transmission electrode 70 and the first transmission electrode 50 may be symmetrically arranged on both sides of the substrate 10 , that is, the second contact electrode 60 and the first contact electrode 40 are also symmetrically arranged on both sides of the substrate 10 .

[0096] In the first direction L1, since the first contact electrode 40 (or the first transmission electrode 50) located on the first surface side of the substrate 10 is aligned with the second contact electrode 60 (or the second transmission electrode 70) located on the second surface side of the substrate 10, the space on the two side surfaces can be fully utilized to arrange more contact electrodes (or transmission electrodes), which is particularly suitable for photovoltaic cells 100 with higher battery energy density.

[0097] In the first direction L1, the second transmission electrodes 70 and the first transmission electrodes 50 may also be arranged alternately relative to the two sides of the substrate 10, that is, the second contact electrodes 60 and the first contact electrodes 40 are also arranged alternately on the two sides of the substrate 10, such as Figure 8 shown.

[0098] In the first direction L1, since the first contact electrode 40 (or the first transmission electrode 50) located on the first surface side of the substrate 10 and the second contact electrode 60 (or the second transmission electrode 70) located on the second surface side of the substrate 10 are not aligned but staggered, and the opening positions on the surface passivation layer 30 on both sides are also staggered, the thermal influence of the opening position is relatively more dispersed in the photovoltaic cell 100, thereby avoiding stress concentration and significantly reducing the risk of hidden cracks and fragments. Among them, when multiple photovoltaic cells 100 form a cell string, the second transmission electrode 70 and the first transmission electrode 50 complete the electrical interconnection of adjacent photovoltaic cells 100, without the need to separately set up conductive interconnectors, the process is simple, and the cost is low.

[0099] See also Fig. 9 The photovoltaic cell 100 is a back contact cell. A doping layer 20 and a passivation layer 30 are disposed on the first surface of the substrate 10 . The second transmission electrode 70 is also disposed on the first surface and is an opposite electrode adjacent to the first transmission electrode 50 .

[0100] On the first surface side, the first contact electrode 40 passes through the passivation layer 30 corresponding to the first surface to electrically contact the doping layer 20 corresponding thereto, and the first transmission electrode 50 is located on and electrically connected to the first contact electrode 40, thereby realizing the current collection and conduction from the doping layer 20 of a certain polarity to the first contact electrode 40 to the first transmission electrode 50 on the first surface side. In addition, the second contact electrode 60 also passes through the passivation layer 30 corresponding to the first surface to electrically contact the doping layer 20 corresponding thereto, and the second transmission electrode 70 is located on and electrically connected to the second contact electrode 60, thereby realizing the current collection and conduction from the doping layer 20 of another polarity to the second contact electrode 60 to the second transmission electrode 70 on the first surface side.

[0101] Please continue reading Figure 8 and Fig. 9 The distance from the lowest point of the free end of the second portion 52 of the first transmission electrode 50 to the highest point of the corresponding end of the second transmission electrode 70 in the second direction L2 is W5, and 0.01≤W5≤1.5mm. For example, 0.01mm, 0.1mm, 0.3mm, 0.5mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.5mm, etc.

[0102] In this embodiment, the distance from the lowest point of the free end of the second portion 52 of the first transmission electrode 50 to the highest point of the corresponding end of the second transmission electrode 70 in the second direction L2 is set to W5, and 0.01≤W5≤1.5mm, which can effectively ensure that the non-interconnected end of the first transmission electrode 50 does not contact the adjacent second transmission electrode 70 of the opposite sex, thereby avoiding the short circuit phenomenon caused by the contact of adjacent opposite electrodes.

[0103] Please continue reading Figure 8 and Fig. 9 , ends of the second transmission electrodes 70 corresponding to the non-interconnected ends of the first transmission electrodes 50 extend beyond the edge of the substrate 10 .

[0104] On the non-interconnected end side of the first transmission electrode 50, the end portion corresponding to the second transmission electrode 70 is arranged beyond the edge of the substrate 10, which is equivalent to extending the length of the second transmission electrode 70 beyond the connection portion of the second contact electrode 60 closest to the edge of the substrate 10, which can effectively ensure the electrical contact between the second transmission electrode 70 and the connection portion of the second contact electrode 60 closest to the edge of the substrate 10, thereby improving the connection strength between the second transmission electrode 70 and the second contact electrode 60 and the current collection capacity of the second transmission electrode 70, thereby reducing the occurrence of leakage and improving the yield and performance of the photovoltaic cell 100.

[0105] In some embodiments, see Figure 8 , the length of the portion of the end of the second transmission electrode 70 corresponding to the non-interconnected end of the first transmission electrode 50 extending beyond the edge of the substrate 10 in the third direction L3 is W6, and 0.01≤W6≤5mm. For example, W6 can be 0.01mm, 0.6mm, 0.8mm, 1.2mm, 1.5mm, 2.2mm, 2.5mm, 3.5mm, 4.5mm, 4.8mm, 5mm, etc.

[0106] With such arrangement, on the non-interconnected end side of the first transmission electrode 50, it can be ensured that the length of the connection portion of the second transmission electrode 70 that exceeds the second contact electrode 60 and is closest to the edge of the substrate 10 will not be too long, thereby avoiding the passivation layer 30 of the adjacent photovoltaic cell 100 being damaged by the second transmission electrode 70 due to excessive length of W6, and the short circuit problem caused by the part of the second transmission electrode 70 corresponding to W6 swinging back and forth during the subsequent production process of the photovoltaic cell 100 and the photovoltaic module.

[0107] Fig.10 This is a perspective view of a photovoltaic cell provided in an embodiment of the present application.

[0108] Reference Fig.10At least one first contact electrode 40 is a discontinuous structure, and the discontinuous structure includes a plurality of sub-first contact electrodes 41 arranged at intervals in the third direction L3. The plurality of sub-first contact electrodes 41 can be arranged in one row or in multiple rows in the third direction L3, and this application does not make any specific limitation.

[0109] Specifically, Fig.10 In the first row shown in FIG. 1 , a plurality of sub-first contact electrodes 41 are arranged in a row along the third direction L3, and the row of sub-first contact electrodes 41 constitutes a first contact electrode 40; Fig.10 In the second row shown in FIG, the first contact electrode 40 may be a strip-shaped structure extending along the third direction L3 as a whole; Fig.10 In the fourth row shown in FIG, a plurality of strip-shaped sub-first contact electrodes 41 and a column-shaped sub-first contact electrode 41 form a first contact electrode 40; Fig.10 In the last row shown in FIG. 1 , a plurality of sub-first contact electrodes 41 are arranged into two rows, and the two rows of sub-first contact electrodes 41 constitute a first contact electrode 40 .

[0110] Regardless of whether the first contact electrode 40 is an integral structure or a discontinuous structure, each first contact electrode 40 is connected to a corresponding first transmission electrode 50. When the first contact electrode 40 is a discontinuous structure, a plurality of sub-first contact electrodes 41 in the first contact electrode 40 are electrically connected to the corresponding first transmission electrode 50. At this time, the first end of the first contact electrode 40 refers to a sub-first contact electrode 41 at the non-interconnected end of the first transmission electrode 50, which is closest to the corresponding edge of the substrate 10.

[0111] By providing a first contact electrode 40 with a discontinuous structure, the distribution area of ​​the first contact electrode 40 is made more localized, which can effectively reduce surface recombination and reduce the setting cost of the first contact electrode 40. Moreover, a plurality of sub-first contact electrodes 41 arranged at intervals in the extension direction of the first transmission electrode 50 can be provided as partial positioning of the first transmission electrode 50, which can improve the setting accuracy of the first transmission electrode 50.

[0112] Specifically, the length of each sub-first contact electrode 41 in the second direction L2 is 0.02-0.2 mm, and the length in the third direction L3 is 0.02-5 mm. For example, the length of each sub-first contact electrode 41 in the second direction L2 may be 0.02 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, etc.; the length of each sub-first contact electrode 41 in the third direction L3 may be 0.02 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0113] Setting the length of the sub-first contact electrode 41 in the second direction L2 within the above range, and setting the length of the sub-first contact electrode 41 in the third direction L3 within the above range, can ensure that the first contact electrode 40 has the minimum resistance while realizing the function of collecting and transmitting current, thereby improving the transmission efficiency.

[0114] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A photovoltaic cell (100), characterized in that: include: A substrate (10), wherein a direction perpendicular to the substrate (10) is a first direction (L1), and two directions perpendicular to the first direction (L1) and perpendicular to each other are a second direction (L2) and a third direction (L3); A doping layer (20) and a passivation layer (30) are sequentially stacked on the first surface of the substrate (10); A first contact electrode (40) passes through the passivation layer (30) and contacts the doping layer (20); A first transmission electrode (50) located on the first contact electrode (40) and electrically connected to the first contact electrode (40); The first contact electrode (40) and the first transmission electrode (50) located thereon both extend along a third direction (L3); the first transmission electrode (50) is used for interconnecting two adjacent photovoltaic cells (100); The first transmission electrode (50) includes a non-interconnected end, and the first contact electrode (40) includes a first end portion closest to the non-interconnected end; the length of the first transmission electrode (50) between the first end portion and an end point of the non-interconnected end is W2, and the length from the first end portion to a corresponding edge of the substrate (10) in a third direction (L3) is W1, and W2>W1.

2. The photovoltaic cell (100) according to claim 1, characterized in that: W2>0.5mm.

3. The photovoltaic cell (100) according to claim 1, characterized in that: W2<5mm.

4. The photovoltaic cell (100) according to claim 1, characterized in that: W1>0.3mm.

5. The photovoltaic cell (100) according to claim 1, characterized in that: The first transmission electrode (50) includes a first portion (51) and a second portion (52) at the non-interconnected end extending away from the first portion (51).

6. The photovoltaic cell (100) according to claim 5, characterized in that: The deviation distance of the second portion (52) from the first portion (51) is W3, W3≥0.05mm, preferably, W3≥0.1mm.

7. The photovoltaic cell (100) according to claim 5, characterized in that: The length of the orthographic projection of the second portion (52) on the base (10) in the third direction (L3) is W4, and W4<W1.

8. The photovoltaic cell (100) according to any one of Claims 7, characterized in that: W4 satisfies 0.01≤W4≤5mm.

9. The photovoltaic cell (100) according to claim 5, characterized in that: The photovoltaic cell (100) further comprises a second contact electrode (60) and a second transmission electrode (70) arranged on a second surface of the substrate (10) opposite to the first surface, wherein the second transmission electrode (70) is an opposite-polarity electrode symmetrically arranged with respect to the substrate (10) and the first transmission electrode (50).

10. The photovoltaic cell (100) according to claim 5, characterized in that: The photovoltaic cell (100) further comprises a second contact electrode (60) and a second transmission electrode (70) arranged on a second surface of the substrate (10) opposite to the first surface, wherein the second transmission electrode (70) is an opposite-polarity electrode arranged alternately with the first transmission electrode (50) relative to the substrate (10).

11. The photovoltaic cell (100) according to claim 5, characterized in that: The photovoltaic cell (100) further comprises a second contact electrode (60) and a second transmission electrode (70) arranged on the first surface, wherein the second transmission electrode (70) is an electrode of opposite polarity adjacent to the first transmission electrode (50).

12. The photovoltaic cell (100) according to any one of claims 9 to 11, characterized in that: The distance from the lowest point of the free end of the second portion (52) to the highest point of the corresponding end of the second transmission electrode (70) in the second direction (L2) is W5, and 0.01≤W5≤1.5 mm.

13. The photovoltaic cell (100) according to claim 9 or 10, characterized in that: An end portion of the second transmission electrode (70) corresponding to a non-interconnected end of the first transmission electrode (50) extends beyond an edge of the substrate (10).

14. The photovoltaic cell (100) according to claim 13, characterized in that: The length of the portion of the end portion extending beyond the edge of the substrate (10) in the third direction (L3) is W6, and 0.01≤W6≤5mm.

15. The photovoltaic cell (100) according to claim 1, characterized in that: At least one of the first contact electrodes (40) is a discontinuous structure; the discontinuous structure comprises a plurality of sub-first contact electrodes (41) arranged at intervals, and the plurality of sub-first contact electrodes (41) are electrically connected to the corresponding first transmission electrodes (50) at the same time.

16. The photovoltaic cell (100) according to claim 15, characterized in that: The length of the sub-first contact electrode (41) in the second direction (L2) is 0.02-0.2 mm, and the length in the third direction (L3) is 0.02-5 mm.

17. A photovoltaic module, characterized in that: Comprising: comprising: the photovoltaic cell (100) as claimed in any one of claims 1 to 16; two adjacent photovoltaic cells (100) are interconnected via the first transmission electrode (50).

18. The photovoltaic module according to claim 17, characterized in that: At least two adjacent photovoltaic cells (100) partially overlap.

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