Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell comprises a semiconductor substrate, wherein the semiconductor substrate comprises a first surface and a second surface which are opposite; the plurality of first current collection electrodes are arranged on the first surface of the semiconductor substrate, and the plurality of first current collection electrodes extend along the first direction and are arranged at intervals along the second direction; the first current collection electrode comprises a plurality of first contact parts and a first transmission part, and the plurality of first contact parts are distributed at intervals in the first direction; the first transmission parts are arranged on the sides, away from the semiconductor substrate, of the first contact parts, are in contact connection with the multiple first contact parts and extend in the first direction; in at least one pair of adjacent first collector electrodes, the distance between at least one pair of adjacent first contact parts in the first direction is smaller than or equal to the distance between the pair of adjacent first collector electrodes in the second direction.

Description

Technical Field

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

[0002] Currently, in the preparation process of solar cells, high-temperature paste is usually printed on the passivation layer first, or laser grooving combined with electroplating (or evaporation) is used to form electrodes, and then sintering is performed to allow the high-temperature paste or electroplating material to burn through the passivation layer and contact the doped conductive layer.

[0003] Due to the existing electrode preparation process, a large amount of high-temperature slurry or electroplating material is required to form the electrode to ensure that the electrode can penetrate the passivation layer and achieve good contact with the doped conductive layer, resulting in higher battery costs. In addition, since the entire electrode is burned through the passivation layer and contacts the doped conductive layer, the passivation effect of the passivation layer is poor. In summary, it is necessary to provide a solution that can take into account the contact performance, production cost and passivation performance of the electrode. Summary of the Invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present invention provides a solar cell and a photovoltaic module.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] According to an embodiment of one aspect of the present invention, there is provided a solar cell, comprising:

[0007] a semiconductor substrate comprising a first surface and a second surface opposite to each other;

[0008] and a plurality of first collector electrodes disposed on the first surface of the semiconductor substrate, the plurality of first collector electrodes extending along the first direction and spaced apart along the second direction; the first collector electrodes comprising a plurality of first contact portions and first transmission portions, the plurality of first contact portions being spaced apart along the first direction; the first transmission portions being disposed on a side of the first contact portion away from the semiconductor substrate and being in contact with and connected to the plurality of first contact portions, the first transmission portions extending along the first direction;

[0009] Among them, in at least one pair of adjacent first collecting electrodes, a spacing between at least one pair of adjacent first contact portions in the first direction is less than or equal to a spacing between the pair of adjacent first collecting electrodes in the second direction.

[0010] According to another embodiment of the present invention, a photovoltaic assembly is provided, comprising: a plurality of the aforementioned solar cells connected into a solar cell string; and an encapsulation layer covering surfaces of the plurality of solar cells.

[0011] According to the solar cell provided by the above-mentioned embodiment of the present invention, the first collector electrode is configured to include a plurality of discontinuously distributed contact portions and a transmission portion that is in contact with the plurality of contact portions, wherein the contact portion can be made of high-temperature slurry. While ensuring contact performance, the discontinuous distribution of the plurality of contact portions can save the amount of high-temperature slurry used to make the contact portions, thereby helping to reduce the cost of preparing the electrode and, in turn, the cost of the battery. At the same time, the discontinuous distribution of the plurality of contact portions can reduce damage to the passivation layer and the doped conductive layer, thereby helping to improve the passivation performance. Furthermore, in at least one pair of adjacent first collector electrodes, by setting the spacing between adjacent first contact portions to be smaller than the spacing between adjacent first collector electrodes in the second direction, while saving electrode slurry, the electrode carrier collection effect can be taken into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0013] Figure 1 A schematic top view of a solar cell provided by an embodiment of the present invention;

[0014] Figure 2 for Figure 1 A schematic cross-sectional view along line A1-A2;

[0015] Figure 3 A schematic side view of a solar cell provided by an embodiment of the present invention;

[0016] Figure 4 A schematic side view of a solar cell provided by another embodiment of the present invention;

[0017] Figure 5 A schematic top view of a first current collecting electrode and a second current collecting electrode provided in an embodiment of the present invention;

[0018] Figure 6A-6B SEM images of cross sections of the first contact portion and the first transmission portion provided by an embodiment of the present invention;

[0019] Figure 7 A schematic top view of a solar cell provided by an embodiment of the present invention;

[0020] Figure 8 A schematic top view of a solar cell provided in another embodiment of the present invention;

[0021] Figure 9 A schematic top view of a first current collecting electrode and a first welding point provided in an embodiment of the present invention;

[0022] Figure 10A schematic top view of a solar cell provided in another embodiment of the present invention;

[0023] Figure 11 A schematic top view of a first current collecting electrode provided in an embodiment of the present invention;

[0024] Figure 12 A schematic top view of a first current collecting electrode provided in another embodiment of the present invention.

[0025] Description of reference numerals:

[0026] 10: semiconductor substrate; 21: first doped conductive layer; 22: second doped conductive layer; 30: passivation layer; 31: first passivation layer; 32: second passivation layer; 41: first collecting electrode; 411: first contact portion, 412: first transmission portion; 413: third contact portion; 42: second collecting electrode; 421: second contact portion, 422: second transmission portion; 43: first bus bar; 431: first bus bar electrode; 432: first welding point; 433: first terminal line; 44: second bus bar; 442: second welding point; 411a: first metal particles; 411b: first organic matter; 411c: metal silicide particles; 412a: second metal spherical particles; 412b: second metal flake particles; 50: tunneling layer; 51: first tunneling layer; 52: second tunneling layer; 60: anti-reflection layer; B: end portion. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0028] In the following detailed description, for ease of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is apparent that one or more embodiments may be practiced without these specific details. In addition, in the following description, descriptions of known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present invention.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0030] When expressions such as “at least one of A, B, and C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, “a system having at least one of A, B, and C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.). When expressions such as “at least one of A, B, or C, etc.” are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, “a system having at least one of A, B, or C” should include but is not limited to systems having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, and C, etc.).

[0031] The relative position between two components (such as film layers or regions) mentioned in the present invention, such as "above", "upper" or "above", may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. Similarly, the relative position between two components mentioned in the present invention, such as "under", "lower" or "below", may refer to the two components being in direct contact, or may refer to the two components being in indirect contact. For example, when one component (such as a film layer or region) is referred to as "on another component", it can be directly on the other component, or there can be other components between the two. On the other hand, when a component is referred to as "directly on the other component", there is no component between the two. In addition, when one component is referred to as "on the other component", the two have a top-down relationship in the top-down direction, and this component can be above or below the other component, so this top-down relationship depends on the orientation of the device.

[0032] In the related art, in the preparation process of solar cells, it is generally adopted to first print a high-temperature paste on the passivation layer to form an electrode, and then sinter it so that the high-temperature paste passes through the passivation layer and contacts the doped conductive layer. Due to the existing electrode preparation process, a large amount of high-temperature paste is required to form the electrode, so as to ensure that the electrode can penetrate the passivation layer and achieve good contact with the doped conductive layer, resulting in a high battery cost. In addition, since the entire electrode is burned through the passivation layer and contacts the doped conductive layer, the passivation effect of the passivation layer is poor. In summary, it is necessary to provide a solution that can take into account the contact performance, production cost and passivation performance of the electrode.

[0033] In the process of implementing the concept of the present invention, it was discovered that the electrode can be configured to include multiple discontinuously distributed contact portions and a transmission portion that is in contact with the multiple contact portions, wherein the contact portions can be made of high-temperature slurry or electroplating material. While ensuring contact performance, the discontinuous distribution of the multiple contact portions can save the amount of high-temperature slurry or electroplating material used to make the contact portions, and the transmission portion can be made of base metal slurry, thereby reducing the cost of preparing the electrode. However, in the extension direction of the collector electrode, if the spacing between adjacent contact portions is too large, it is not conducive to carrier collection, and if the spacing between adjacent contact portions is too small, it will lead to large-scale burn-through of the passivation layer, easily causing passivation damage, which is not conducive to the passivation effect of the passivation layer.

[0034] In view of this, the present invention provides a solar cell and a photovoltaic module, which improve the cell efficiency by balancing the length of the contact portion along the extending direction of the collector electrode and the spacing between adjacent contact portions.

[0035] Figure 1 A schematic top view of a solar cell provided by an embodiment of the present invention.

[0036] Figure 2 for Figure 1 Schematic cross-section diagram along line A1-A2.

[0037] According to an embodiment of one aspect of the present invention, a solar cell is provided, referring to Figure 1 、 Figure 2 As shown, it includes a semiconductor substrate 10 and a plurality of first collecting electrodes 41, wherein:

[0038] A plurality of first collecting electrodes 41 are disposed on the first surface 10 a of the semiconductor substrate 10 . The plurality of first collecting electrodes 41 extend along a first direction X and are spaced apart along a second direction Y. The first collecting electrodes 41 include a plurality of first contact portions 411 and a first transmission portion 412 . The plurality of first contact portions 411 are spaced apart along the first direction X. The first transmission portion 412 is disposed on a side of the first contact portion 411 away from the semiconductor substrate 10 and is in contact with and connected to the plurality of first contact portions 411 . The first transmission portion 412 extends along the first direction X. The first direction X and the second direction Y intersect.

[0039] In some embodiments, in at least one pair of adjacent first collecting electrodes 41 , a distance R2 between at least one pair of adjacent first contact portions 411 in the first direction X is less than or equal to a distance P between the pair of adjacent first collecting electrodes 41 in the second direction Y.

[0040] According to an embodiment of the present invention, the spacing P between adjacent first collecting electrodes 41 in the second direction Y takes into account both the material usage of the first collecting electrodes 41 and the carrier collection distance in the second direction Y. If the spacing P is too small, the material usage of the first collecting electrodes 41 is excessive and the light shielding is severe. If the spacing P is too large, the carrier collection distance is large, which is not conducive to the carrier collection efficiency and causes severe internal carrier recombination. Therefore, when the material, energy band, doping concentration, etc. of the first doped conductive layer are different, the spacing P that can be designed is often also different. After the spacing P of the first collecting electrodes 41 is optimized and determined, the spacing R2 between the first contact portions in the first direction X depends on the setting of the spacing P of the first collecting electrodes 41. In order to ensure that the first contact portions can collect carriers along the first direction, it is necessary to set the spacing R2 to be less than or equal to the spacing P. If the spacing R2 is too large, it will be detrimental to carrier collection between two adjacent first contact portions. If the spacing R2 is too small, while the improvement in carrier collection efficiency is limited, it will lead to excessive use of first contact portions, resulting in unnecessary material consumption. Moreover, since the length of the first contact portions is relatively large, it will cause significant damage to the passivation layer and the doped conductive layer, resulting in a decrease in the passivation effect of the passivation layer. Therefore, the spacing R2 is set to be less than or equal to the spacing P. Furthermore, in order to more quickly collect and export collected carriers, the spacing R2 is preferably less than the spacing P.

[0041] In some embodiments, in at least one pair of adjacent first collecting electrodes 41, the ratio of the spacing R2 between at least one pair of adjacent first contact portions 411 in the first direction X to the spacing P between the adjacent first collecting electrodes 41 in the second direction Y is less than or equal to 0.8. For example, the ratio may be 0.2, 0.4, 0.5, or 0.8, but is not limited to these values. The first collecting electrodes 41 collect current in the second direction Y, and their first transmission portions 412 primarily perform transmission, while the first contact portions 411 primarily collect carriers from the semiconductor layer. Thus, by further controlling the spacing R2 / pitch P ratio, the first contact portions can withstand higher currents or collect more carriers.

[0042] It should be noted that the pitch P between adjacent first collecting electrodes 41 in the second direction Y can be expressed as the distance between the center lines of adjacent first collecting electrodes 41 extending along the first direction X. The pitch R2 between adjacent first contact portions 411 in the first direction is the distance between two relatively close edges of adjacent first contact portions 411.

[0043] The spacing P between adjacent first collecting electrodes 41, or R2 between adjacent first contact portions 411, can be measured using a scanning electron microscope (SEM) or a ruler. For example, a top view of the first collecting electrode can be obtained first, and the center line of the first collecting electrode can be extracted using an image processing algorithm or visual inspection, and the spacing P between the center lines of adjacent first collecting electrodes can be measured. Alternatively, based on the height difference between the area with the first contact portion and other areas on the first collecting electrode, and the obvious brightness difference in the figure, the distance between two relatively close edges of the first contact portions can be directly measured on the figure.

[0044] It is understood that the aforementioned "at least one pair of adjacent first collecting electrodes 41" may refer to a single pair of adjacent first collecting electrodes, or multiple pairs of adjacent first collecting electrodes. In the case of multiple pairs of adjacent first collecting electrodes, these may refer to some or all of the adjacent first collecting electrodes. Similarly, the aforementioned "at least one pair of adjacent second collecting electrodes 42" also applies, and will not be further elaborated. Unless otherwise specified, the "at least one first collecting electrode 41" and "at least one second collecting electrode 42" hereinbelow refer to the aforementioned meanings.

[0045] According to some embodiments of the present invention, the plurality of first contact portions 411 included in each of the plurality of first collector electrodes 41 are regularly arranged over at least a portion of the passivation layer 30, and the plurality of second contact portions 421 included in each of the plurality of second collector electrodes 42 are regularly arranged over at least a portion of the passivation layer 30. It is understood that "regular arrangement" means that one or more first contact portions 411, and the spacing between one or more adjacent first contact portions 411, constitute a repeating unit, and that the repeating unit is repeatedly arranged according to the same regular pattern. For example, for each first collector electrode 41, the plurality of first contact portions 411 may be spaced apart in the first direction at the same spacing. In this case, the lengths of the plurality of first contact portions 411 along the first direction may be equal, or may vary periodically, such as alternating between the first length and the second length. Alternatively, "regular arrangement" may also mean that, for each first collector electrode 41, the plurality of first contact portions 411 have the same lengths along the first direction and are spaced apart in the first direction at periodically varying spacings. The same applies to a second collector electrode 42 and will not be further described. Unless otherwise specified, the term "regular arrangement" hereinbelow refers to the aforementioned meaning.

[0046] According to an embodiment of the present invention, the material of the semiconductor substrate 10 can be an N-type, P-type, or intrinsic crystalline silicon substrate. For example, it can be a semiconductor material selected from the group consisting of single crystal silicon, polycrystalline silicon, and microcrystalline silicon. It can also be an N-type or P-type single crystal silicon substrate. The conversion efficiency of cells based on single crystal silicon substrates is higher than that of other types, such as polycrystalline silicon cells. By introducing donor impurities such as Group VA elements such as phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, an N-type crystalline silicon substrate is obtained. Alternatively, by introducing acceptor impurities such as Group IIIA elements such as boron (B), aluminum (Al), or gallium (Ga), a P-type crystalline silicon substrate is obtained.

[0047] According to an embodiment of the present invention, the first surface 10a of the semiconductor substrate 10 can be the front or back of the battery, without limitation. Generally speaking, the front of the battery serves as the light-receiving surface, and the back serves as the backlight surface. Alternatively, the battery can be double-sided, with both the front and back serving as light-receiving surfaces.

[0048] According to an embodiment of the present invention, by configuring the first current collecting electrode to include multiple discontinuously distributed contact portions and a transmission portion that contacts and connects to the multiple contact portions, wherein the contact portions can be made of a high-temperature slurry, or by laser grooving combined with electroplating or evaporation, the discontinuous distribution of the multiple contact portions can save material for making the contact portions while ensuring contact performance, thereby helping to reduce the cost of manufacturing the electrodes and, in turn, the cost of the battery. Furthermore, in at least one pair of adjacent first current collecting electrodes, by configuring the spacing between adjacent first contact portions to be smaller than the spacing between adjacent first collecting electrodes in the second direction, electrode slurry can be saved while also ensuring effective carrier collection.

[0049] In an embodiment of the present invention, the above-mentioned solar cell also includes: a first doped conductive layer 21, arranged on the first surface 10a of the semiconductor substrate 10; a passivation layer 30, arranged on the side of the first doped conductive layer 21 away from the semiconductor substrate 10; wherein, a plurality of first collecting electrodes 41 are arranged on the side of the passivation layer away from the first doped conductive layer 21; a plurality of first contact portions 411 pass through the passivation layer and are electrically connected to the first doped conductive layer 21; the conductivity type of the first doped conductive layer 21 is the same as the conductivity type of the semiconductor substrate 10.

[0050] According to an embodiment of the present invention, since the conductivity type of the first doped conductive layer 21 is the same as the conductivity type of the semiconductor substrate 10, the first doped conductive layer 21 transmits majority carriers at this time, and the spacing R2 between adjacent first contact portions 411 in the first collecting electrode 41 in the first direction X is appropriately enlarged, which can also ensure the collection effect of majority carriers, and at the same time reduce the amount of electrode material used and reduce damage to the passivation layer 30. However, it should still at least meet the requirement that the spacing R2 is less than or equal to the spacing P, otherwise it will be detrimental to the collection and transmission of majority carriers.

[0051] According to an embodiment of the present invention, the first doped conductive layer 21 may be a semiconductor material, such as single crystal silicon, polycrystalline silicon, or microcrystalline silicon. It may be formed by in-situ doping in the semiconductor substrate 10, or by an additional deposition layer (e.g., ALD, CVD, etc.). When an additional deposition layer is used, an interface layer may be provided between the first doped conductive layer 21 and the semiconductor substrate 10. For example, this may be an intrinsic amorphous silicon (corresponding to a heterojunction passivation structure) or an oxide layer (e.g., silicon oxide, corresponding to a TOPCon passivation structure).

[0052] According to an embodiment of the present invention, the passivation layer 30 can be an interface passivation layer, an anti-reflection layer, or a stacked combination of these layers. It can protect and passivate the semiconductor substrate 10 or other functional layers, such as the first doped conductive layer 21, located beneath the passivation layer 30. For example, the passivation layer 30 can be a single layer formed from a material selected from silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, or amorphous silicon, or a stacked layer comprising one or more of these materials. For example, an aluminum oxide passivation layer can be first deposited using a method such as ALD (atomic layer deposition), and then one or more silicon nitride layers can be deposited thereon using methods such as PECVD.

[0053] In some embodiments, the first collecting electrodes can be designed with different spacing P depending on the type of solar cell or the material, energy band, doping concentration, etc. of the first doped conductive layer. Generally, the spacing P of at least one pair of adjacent first collecting electrodes 41 in the second direction Y is 0.5-1.5 mm, for example, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, or 1.5 mm, but is not limited to these values. If the spacing P is too large, for example, greater than 1.5 mm, the carrier collection distance between adjacent first collecting electrodes is large, which can easily cause internal carrier recombination and be detrimental to carrier collection. If the spacing P is too small, for example, less than 0.2 mm, the first collecting electrodes are severely blocked from light, which reduces light utilization and wastes the material used to prepare the first collecting electrodes.

[0054] In some embodiments, the intervals P between different adjacent first collecting electrodes 41 in the second direction Y may be the same or different.

[0055] In some embodiments, in at least one first collecting electrode 41, the spacing R2 between at least one pair of adjacent first contact portions 411 in the first direction X is less than or equal to 1.5 mm. A large number of verification results confirm that when R2 exceeds 1.5 mm, which is related to the spacing P between adjacent first collecting electrodes 41, the battery power will be reduced, which is not conducive to current collection. Furthermore, the R2 value range is between 0.2-1.5 mm, for example, it can be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.5 mm, but is not limited to the values ​​cited. If R2 is less than 0.2, on the one hand, the passivation effect of the passivation layer will be reduced, and on the other hand, it will cause necessary material consumption. The R2 value range is further preferably 0.2-1.2 mm.

[0056] In some embodiments, the solar cell can be a double-sided contact cell, in which case the solar cell can further include: a plurality of second collecting electrodes 42, arranged on the second surface 10b, or the solar cell can be a back-contact cell, in which case the plurality of second collecting electrodes 42 are arranged on the first surface 10a and are alternately spaced with the plurality of first collecting electrodes 41.

[0057] In some embodiments, the second collector electrode 42 can adopt a structure similar to the first collector electrode, with a discontinuously distributed second contact portion. Specifically, multiple second collector electrodes 42 extend along the first direction X and are spaced apart along the second direction Y. The second collector electrode 42 includes multiple second contact portions 421 and second transmission portions 422, with the multiple second contact portions 421 spaced apart along the first direction X. The second transmission portions 422 are disposed on a side of the second contact portion 421 away from the semiconductor substrate 10 and are in contact with and connected to the multiple second contact portions 421. The second transmission portions 422 extend along the first direction X. This helps to further save the amount of high-temperature slurry or electroplating material while ensuring the carrier collection effect. It is understood that this is not limited to this. In other embodiments, the second collector electrode 42 can also adopt a traditional electrode structure, that is, the second contact portion extends continuously and is an integrated structure with the second transmission portion 422.

[0058] In order to further illustrate the specific applicable structures of the discontinuously distributed contact portions of the first collecting electrode 41 and the second collecting electrode 42 for different types of solar cells, first, a double-sided contact solar cell is used as an example. Figure 3 Schematic side view of a solar cell provided by an embodiment of the present invention. Figure 3As shown, the above-mentioned solar cell also includes a second doped conductive layer 22, which is arranged on the second surface 10b of the semiconductor substrate 10. The second doped conductive layer 22 and the first doped conductive layer 21 are arranged opposite to each other, and the conductivity type of the second doped conductive layer 22 and the semiconductor substrate 10 are opposite; the passivation layer 30 is also arranged on the side of the second doped conductive layer 22 away from the semiconductor substrate 10, and specifically may include a first passivation layer 31 and a second passivation layer 32, the first passivation layer 31 is arranged on the side of the first doped conductive layer 21 away from the semiconductor substrate 10, and the second passivation layer 32 is also arranged on the side of the second doped conductive layer 22 away from the semiconductor substrate 10; a plurality of second collecting electrodes 42 are arranged on the side of the second passivation layer 32 away from the second doped conductive layer 22, and a plurality of second contact portions 421 of the second collecting electrode 42 are electrically connected to the second doped conductive layer 22 through the second passivation layer 32.

[0059] At this time, the first surface 10a of the semiconductor substrate 10 can be the front or back of the battery, without limitation. Generally speaking, the front of the battery is used as the light-receiving surface, and the back is used as the backlight surface, or both sides can be used as light-receiving surfaces.

[0060] In an embodiment of the present invention, the second doped conductive layer 22 may be a semiconductor material, such as single crystal silicon, polycrystalline silicon, or microcrystalline silicon. It may be formed by in-situ doping in the semiconductor substrate 10, or by an additional deposition layer (e.g., by ALD, CVD, etc.). When an additional deposition layer is used, an interface layer may be provided between the second doped conductive layer and the semiconductor substrate. For example, this may be an intrinsic amorphous silicon (corresponding to a heterojunction passivation structure) or an oxide layer (e.g., silicon oxide, corresponding to a TOPCon passivation structure).

[0061] For example, taking the double-sided contact cell as a tunneling oxide passivation contact (TOPCon) cell, the semiconductor substrate 10 can be an N-type silicon substrate, the first doped conductive layer 21 can be an N-type doped polysilicon layer prepared on the second surface 10b by low-pressure chemical vapor deposition; the second doped conductive layer 22 can be a P-type doped layer formed by boron diffusion doping in the first surface 10a of the semiconductor substrate 10.

[0062] In this case, the solar cell may further include a tunneling layer 50 , which is located between the first doped conductive layer 21 and the semiconductor substrate 10 and forms a tunneling passivation contact structure with the first doped conductive layer 21 .

[0063] According to embodiments of the present invention, the passivation layer 30 can be an interface passivation layer, an anti-reflection layer, or a stacked combination of these layers. It can protect and passivate the semiconductor substrate or other functional layers, such as the first doped conductive layer or the second doped conductive layer, located beneath the passivation layer 30. For example, the passivation layer 30 can be a single layer formed from a material selected from silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, or amorphous silicon, or a stacked layer comprising one or more of these materials. For example, an aluminum oxide passivation layer can be first deposited using a method such as ALD (atomic layer deposition), and then one or more silicon nitride layers can be deposited thereon using methods such as PECVD.

[0064] Secondly, taking the solar cell as a back contact cell as an example, Figure 4 A schematic side view of a solar cell according to another embodiment of the present invention is shown. Figure 4 As shown, the main difference from the above-mentioned bifacial contact solar cell is that the second doped conductive layer 22 and the first doped conductive layer 21 are alternately arranged on the first surface 10a; the passivation layer 30 is also arranged on the side of the second doped conductive layer 22 away from the semiconductor substrate 10. In this case, multiple second collecting electrodes 42 are arranged on the side of the passivation layer 30 away from the second doped conductive layer 22, and the multiple second contact portions 421 of the second collecting electrodes 42 pass through the passivation layer 30 to electrically connect to the second doped conductive layer 22.

[0065] In this case, the first surface 10a of the semiconductor substrate 10 can be the back side of the battery to reduce the shading of the first and second collecting electrodes on the front side of the battery, thereby improving light utilization. Similarly, the front side of the battery serves as the light-receiving side, and the back side serves as the backlight side. Alternatively, the battery can be double-sided, with both the front and back sides serving as light-receiving sides.

[0066] According to an embodiment of the present invention, further optionally, the first surface 10a and / or the second surface 10b may have a suede structure or a polished surface structure, wherein the suede structure may include a combination of one or more structures such as pyramidal and conical shapes. For example, the suede structure may include multiple pyramids, and the polished surface structure may include a combination of one or more structures such as prism-shaped and truncated cone-shaped shapes. For example, the polished surface may include multiple polygonal or arc-shaped tower bases. The specific selection can be based on the contact requirements between the first doped conductive layer and the second doped conductive layer, and is not particularly limited.

[0067] According to an embodiment of the present invention, since the first doped conductive layer 21 and the second doped conductive layer 22 have different conductivity types, the two have different requirements for carrier collection. Specifically, when the conductivity types of the second doped conductive layer 22 and the semiconductor substrate 10 are opposite, the second doped conductive layer 22 transmits minority carriers, which are prone to recombination during the transmission process. Therefore, the spacing Q2 between adjacent second contact portions 421 in the corresponding second collecting electrode in the first direction X should be appropriately reduced, so as to quickly collect minority carriers and achieve a collection balance between majority carriers and minority carriers.

[0068] Therefore, the arrangement of the first contact portion 411 in the first collecting electrode 41 and the second contact portion 421 in the second collecting electrode 42 is differentiated. To facilitate understanding of the differentiated arrangement, Figure 5 Schematic diagram of a top view of the first collecting electrode and the second collecting electrode provided in an embodiment of the present invention. Figure 5 As shown, in at least one first collecting electrode 41, the spacing R2 between at least one pair of adjacent first contact portions 411 is greater than the spacing Q2 between at least one pair of adjacent second contact portions 421 in at least one second collecting electrode 42. In some embodiments, the length Q1 of the second contact portion 421 along the first direction X can be greater than the length R1 of the first contact portion 411 along the first direction X. This configuration facilitates the second collecting electrode 42 to quickly collect minority carriers, balancing the collection effect with that of majority carriers.

[0069] In an embodiment of the present invention, in at least one first collecting electrode 41, the spacing R2 between at least one pair of adjacent first contact portions 411 is 0.3 to 1.5 mm, for example, 0.3 mm, 0.5 mm, 0.6 mm, 0.8 mm, 0.9 mm, 1.2 mm, or 1.5 mm, but is not limited to these values. This configuration allows for the spacing R2 to be appropriately increased when the first collecting electrodes 41 are used to collect majority carriers, but must still be less than or equal to the spacing P between adjacent first collecting electrodes 41. The spacing Q2 between at least one pair of adjacent second contact portions 421 is 0.2 to 1.2 mm, for example, 0.2 mm, 0.5 mm, 0.8 mm, 0.9 mm, 1 mm, or 1.2 mm, but is not limited to these values. This setting is based on the consideration that when the second collecting electrode 42 is used to collect minority carriers, its spacing Q2 can be appropriately reduced. However, when it is less than 0.2, the improvement in the minority carrier collection effect is limited, resulting in unnecessary consumption of electrode materials, and due to the greater damage to the passivation layer 30, it is not conducive to the improvement of the passivation performance.

[0070] In an embodiment of the present invention, the length R1 of the first contact portion 411 in the first direction X also affects the carrier collection effect. Increasing the length facilitates rapid carrier collection. However, excessively long lengths have limited improvement in carrier collection efficiency and increase unnecessary electrode material consumption. Therefore, the length R1 of the first contact portion 411 is 0.2-3 mm. For example, R1 can be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 2 mm, or 3 mm, but is not limited to these values. Thus, setting the length R1 of the first contact portion 411 within the above range can, on the one hand, balance the carrier collection effect and the electrode manufacturing cost, and on the other hand, can coordinate with the spacing between adjacent first contact portions 411 to uniformly collect carriers in the first direction X, avoiding local hot spot effects caused by excessive local current density.

[0071] Similarly, in the embodiment of the present invention, the length Q1 of the second contact portion 421 in the first direction X is 0.2-3 mm. For example, Q1 can be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 2 mm, or 3 mm, but is not limited to these values. The effects thereof are similar to those of the first contact portion 411 and will not be further described. In some embodiments, the length Q1 of the second contact portion 421 along the first direction X can be greater than the length R1 of the first contact portion 411 along the first direction X.

[0072] In an embodiment of the present invention, the first contact portion 411 of the first collector electrode 41 comprises at least one of silver, nickel, titanium, and a transparent conductive oxide (TCO). Examples of TCOs include indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and tungsten-doped indium oxide (IWO). The material of the first contact portion 411 is selected to ensure good ohmic contact with the first doped conductive layer 21, thereby facilitating carrier collection. It also prevents elements in the first transfer portion 412 from diffusing into the first doped conductive layer 21 and potentially damaging it (for example, copper can damage the doped conductive layer).

[0073] In an embodiment of the present invention, in the first collector electrode 41, the first transmission portion 412 may be made of a base metal, including at least one of copper, aluminum, silver-clad copper, and a silver-copper alloy. The material selection for the first transmission portion 412 is primarily based on its conductivity, as it is used to transmit carriers to the first contact portion 411. Therefore, a base metal material with low cost and good conductivity is preferred. Similarly, in the second collector electrode 42, the material options for the second contact portion 421 are consistent with those for the first contact portion 411, and the material options for the second transmission portion 422 are consistent with those for the first transmission portion 412, so further description is omitted.

[0074] In an embodiment of the present invention, in at least one first collecting electrode 41, the ratio of the length R1 of at least one first contact portion 411 along the first direction X to the spacing R2 between adjacent first contact portions 411 is smaller than the ratio of the length Q1 of at least one second contact portion 421 along the first direction X to the spacing Q2 between adjacent second contact portions 421 in at least one second collecting electrode 42. Thus, by controlling the ratio of length to spacing, the effects of the lengths and spacings of the first and second contact portions 411, 421 on the carrier collection effect can be comprehensively considered, thereby more effectively regulating the carrier collection on the first and second collecting electrodes 41, 42. On this basis, since the minority carrier lifetime is shorter than the majority carrier lifetime, by controlling the length of the second contact portion of the second collecting electrode (the second doped conductive layer has a conductivity type opposite to that of the semiconductor substrate, and the second doped conductive layer is suitable for collecting minority carriers) along the first direction and the ratio of the spacing between another contact portion adjacent to the second contact portion is larger, minority carriers can be collected more effectively, the carrier collection balance of the first doped conductive layer and the second doped conductive layer can be achieved, and the battery efficiency can be improved.

[0075] In an embodiment of the present invention, in at least one first collecting electrode 41, the ratio of the length R1 of at least one first contact portion 411 along the first direction X to the spacing R2 between another first contact portion 411 adjacent to the first contact portion 411, or in at least one second collecting electrode 42, the ratio of the length Q1 of at least one second contact portion 421 along the first direction X to the spacing Q2 between another second contact portion 421 adjacent to the second contact portion 421, is 0.3 to 3, for example, 0.3, 0.5, 1, 2, or 3, but is not limited to these values. Thus, by comprehensively considering the effects of the lengths and spacings of the first and second contact portions 411 and 421 on the carrier collection effect, controlling the length-to-spacing ratio of the first and second contact portions 411 and 421 within the above range can avoid unnecessary electrode material loss due to an excessively high length ratio, or poor carrier collection effect due to an excessively low length ratio.

[0076] At this time, the setting of the ratio of the length to the spacing of the two is coordinated with the aforementioned specific length and spacing settings, which is conducive to the uniform arrangement of the first contact portion and the second contact portion in the first direction X, thereby controlling the current density balance at various positions on the first collecting electrode and the second collecting electrode to avoid local overheating.

[0077] Figure 6A-6B This is an SEM image of a cross section of the first contact portion and the first transmission portion provided by an embodiment of the present invention.

[0078] In the embodiment of the present invention, reference Figure 6A 、 Figure 6BAs shown, the first contact portion 411 includes: a plurality of first metal particles 411 a stacked into a honeycomb structure having a plurality of holes, and a first organic matter 411 b distributed between the plurality of first metal particles 411 a.

[0079] In an embodiment of the present invention, the first contact portion 411 may further include: a plurality of metal silicide particles 411 c embedded in the first doped conductive layer 21 , thereby forming an ohmic contact with the first doped conductive layer 21 and improving carrier collection efficiency.

[0080] In an embodiment of the present invention, the first transmission portion 412 includes a plurality of second metal spherical particles 412 a and a plurality of second metal flake particles 412 b , wherein some of the second metal particles are dispersed in at least some of the pores of the honeycomb structure.

[0081] In some embodiments, the cross-sectional shape of the first transmission portion 412 can be, for example, a trapezoidal shape. A trapezoidal-shaped first transmission portion facilitates metal welding and reduces the risk of short circuits caused by welding. The cross-sectional shape of the first transmission portion 412 can be, for example, an elliptical shape. Compared to a trapezoidal-shaped first transmission portion, an elliptical-shaped first transmission portion 412 can reflect less light from the sides, reducing light obstruction.

[0082] According to an embodiment of the present invention, the surface and edge of the first contact portion are generally concave and convex with irregularly stacked grains, with an average line width of 12.6 μm (which varies depending on the specifications of the printing screen); the silver grains have a diameter of 1.1~1.8 μm and have a relatively regular hexagonal flake stacking morphology (which also presents a regular spherical shape depending on the slurry composition system).

[0083] According to an embodiment of the present invention, the overall height of the first contact portion is 0.5-8 μm, the width is 9-25 μm, the aspect ratio is about 23% (depending on the specifications of the printing screen), and it has a honeycomb structure with a hole diameter of 0.5-1.5 μm. The silver is stacked in hexagonal sheets, showing a distinct layered structure (depending on the slurry composition system, it may also be regular spherical). Some organic matter remains between the silver grains and on the silver-silicon contact surface (the contact surface between the first contact portion and the first doped conductive layer), which to a certain extent increases the pull-out force.

[0084] Figure 7 A schematic top view of a solar cell provided by an embodiment of the present invention.

[0085] Figure 8 A schematic top view of a solar cell provided in accordance with another embodiment of the present invention.

[0086] Figure 9 A schematic top view of a first collecting electrode and a first welding point provided in an embodiment of the present invention.

[0087] In an embodiment of the present invention, the solar cell further includes a plurality of first busbars 43 , which are arranged on a side of the passivation layer 30 away from the semiconductor substrate 10 . The plurality of first busbars 43 are arranged at intervals along the first direction X and each extends along the second direction Y. The first busbars 43 are electrically connected to the first collecting electrode 41 .

[0088] In some embodiments, reference Figure 7 As shown, the solar cell is a bifacial solar cell. The bifacial solar cell also includes a plurality of second busbars, which are arranged on the surface opposite to the first busbars. The bifacial solar cell can have a busbar-containing structure, a busbar-free structure, or a partially busbar-free structure.

[0089] In some embodiments, the first busbar-less bifacial solar cell's first busbar ...

[0090] In some embodiments, reference Figure 7 As shown, at least part of the first busbar 43 may further include a first busbar electrode 431 (having a main grid structure) extending continuously along the second direction, and the first welding point 432 is electrically connected to the first busbar electrode 431 .

[0091] like Figure 7 The figure shows a combination of a structure with a busbar and a structure without a busbar, but is not limited thereto. Alternatively, all of the first current collectors 43 may be structures with a busbar, or structures without a busbar.

[0092] In some embodiments, reference Figure 8 As shown, the solar cell is a back-contact solar cell. The back-contact solar cell can have a busbar structure, a busbar-free structure, or a partially busbar-free structure.

[0093] In some embodiments, the first busbar 43 of the back-contact solar cell without a busbar structure includes a first welding point 432 . Furthermore, the solar cell may further include two sets of first terminal wires 433 disposed opposite to each other, with the first welding point 432 located between the first terminal wires 433 .

[0094] In some embodiments, reference Figure 8 As shown, the first busbar 43 may also be replaced by a first busbar electrode (having a main grid structure) extending continuously along the second direction.

[0095] In some embodiments, reference Figure 8 As shown, one of the first collecting electrode 41 and the second collecting electrode 42 is in a discontinuous state.

[0096] In some embodiments, the first collecting electrode 41 and the second collecting electrode 42 are continuous. The first bus electrode 431 of the back-contact solar cell with a busbar structure is connected to one of the first collecting electrode 41 and the second collecting electrode 42, with an insulating block disposed between the other.

[0097] Among them, reference Figure 7 、 Figure 8 、 Figure 9 As shown, the first current collector 43 includes a plurality of first welding points 432 spaced apart along the second direction Y. At the connection location with the first welding point 432 in at least one first collecting electrode 41, the length W3 of the first welding point 432 along the first direction X is greater than the spacing R2 between adjacent first contact portions 411. This arrangement allows the first contact portions to be provided below the first welding points, thereby improving the surface roughness of the first welding points and increasing the contact area between the first welding points and the current collecting structure (such as a welding ribbon, electrical connection wire, or other current collecting structure), thereby enhancing the welding tension and connection reliability of the current collecting structure.

[0098] According to an embodiment of the present invention, the multiple first contact portions 411 included in each of the multiple first collecting electrodes 41 can be arranged in a regular pattern on the passivation layer 30. For example, the lengths of the multiple first contact portions 411 are all equal, and the spacing between adjacent first contact portions 411 is all equal, so that carriers at different positions on the solar cell can be collected more evenly. However, this is not limited to this. Considering the different factors such as carrier collection, mechanical stress, and passivation effect at different positions of the solar cell, the contact portion arrangement of the first and second collecting electrodes can be specially designed in specific areas of the solar cell.

[0099] Figure 10 Schematic diagram of a top view of a solar cell provided by another embodiment of the present invention. Specifically, taking at least one first collecting electrode 41 as an example, refer to Figure 10 As shown, the middle position of the first transmission portion 412 has disconnected portions spaced apart along the first direction. The disconnected portions and / or ends of the first transmission portion 412 have third contact portions 413, and the length R3 of the third contact portion 413 is different from the length R2 of the first contact portion. Similarly, the second collector electrode 42 can be configured similarly to the first collector electrode 41, and will not be further described. Furthermore, the specific application of the third contact portions at the disconnected portions and / or ends of the first transmission portion 412 in different solar cells is described below.

[0100] like Figure 4 and Figure 8As shown, taking a back-contact cell as an example, the solar cell may further include a plurality of second busbars 44 , the passivation layer 30 being arranged on a side away from the semiconductor substrate 10 , the plurality of second busbars 44 being arranged at intervals along the first direction X and each extending along the second direction Y, and the second busbars 44 being electrically connected to the second collecting electrode 42 .

[0101] Similar to the first busbar 43, in a back contact solar cell without a main grid structure, as shown in FIG. Figure 8 As shown, the second busbar 44 may include a second welding point 442. Further, at least part of the second busbar 44 may include two second terminal wires (only one second terminal wire is shown in the figure) disposed opposite to each other, and the second welding point 442 is electrically connected to the second terminal wire.

[0102] At this point, in at least one first collecting electrode, the first transmission portion 412 is disconnected at the intersection with the second terminal line or the second welding point 442, forming a disconnected portion A, thereby electrically isolating the first collecting electrode 41 from the second current bus 44. At this point, the disconnected portion A of the first collecting electrode 41 has a third contact portion, which passes through the passivation layer 30 and contacts the first doped conductive layer 21. By setting the length of the third contact portion at the disconnected portion A to be different from that of the first contact portion, space is provided for the installation of the second current bus, thereby better avoiding the risk of short circuits at the intersection with the second current bus 44.

[0103] Of course, this is not limiting. In a back-contact solar cell with a busbar structure, at least a portion of the current collector may include a second bus electrode extending continuously in the second direction, with the second welding point electrically connected to the second bus electrode. In this case, the first collecting electrode 41 is disconnected at the intersection with the second bus electrode or the second welding point, forming a disconnected portion A. Similarly, by setting the length of the third contact portion at the disconnected portion A to be different from that of the first contact portion, the risk of a short circuit at the intersection with the second bus member 44 can be better avoided.

[0104] In some embodiments, Figure 7 As shown, taking a double-sided contact cell as an example, in the first collector electrode located at the edge of the cell, the first collector electrode 41 is disconnected at the connection position with the first terminal line, forming a disconnection portion A, thereby reducing the mechanical stress at the edge of the solar cell and reducing the risk of cracking. In this case, the first collector electrode 41 has a third contact portion near the disconnection portion A along the first direction X, which passes through the passivation layer 30 and contacts the first doped conductive layer 21. By setting the length of the third contact portion at the disconnection portion A to be different from the length of the first contact portion, both the mechanical stress at the edge of the solar cell and the carrier collection effect can be taken into account.

[0105] In some embodiments, in a double-sided contact cell, a third contact portion is provided at end B of the first collector electrode 41 near the cell edge. The third contact portion penetrates the passivation layer 30 and contacts the first doped conductive layer 21. For back-contact cells, the same arrangement is applied at end B of the first collector electrode 41 near the cell edge, which will not be further described. By setting the length of the third contact portion at end B to be different from that of the first contact portion, both mechanical stress at the solar cell edge and carrier collection efficiency can be balanced.

[0106] Figure 11 A schematic top view of a first current collecting electrode provided in an embodiment of the present invention.

[0107] In the embodiment of the present invention, reference Figure 11 As shown, along the second direction Y, a width D1 of the first contact portion 411 along the second direction Y is smaller than a width D2 of the first transmission portion 412 along the second direction Y.

[0108] In some embodiments, along the second direction Y, the ratio of the width D2 of the first transmission portion 412 along the second direction Y to the width D1 of the first contact portion 411 along the second direction Y is 0.8-2.5; for example, it can be 0.8, 1.0, 1.5, 2, 2.5, but is not limited to the values ​​listed.

[0109] In some embodiments, a width D1 of the first contact portion 411 along the second direction Y is 10-50 μm, and a width D2 of the first transmission portion 412 along the second direction Y is 30-100 μm.

[0110] In an embodiment of the present invention, the width of the first contact portion along the second direction is smaller than the width of the first transmission portion along the second direction, which is beneficial to increase the contact area between the first contact portion and the first transmission portion, thereby reducing the transmission resistance of the first collecting electrode.

[0111] Figure 12 A schematic top view of a first current collecting electrode provided in another embodiment of the present invention.

[0112] In the embodiment of the present invention, reference Figure 12 As shown, in at least one first transmission portion 412 , a plurality of first contact portions 411 electrically connected to the first transmission portion 412 are distributed in at least two rows along the second direction Y;

[0113] Each row includes a plurality of first contact portions 411 arranged along the first direction X, and the first contact portions 411 of two adjacent rows are staggered along the second direction.

[0114] In some embodiments, each row includes a plurality of first contact portions 411 arranged along the first direction X, and the first contact portions 411 of two adjacent rows are end-to-end aligned along the second direction.

[0115] In some embodiments, in at least one first transmission portion 412 , a plurality of first contact portions 411 electrically connected to the first transmission portion 412 are distributed in multiple rows along the second direction Y, for example, 3, 4, 5, 6, or 7 rows, but not limited to the listed values.

[0116] In the embodiment of the present invention, the first contact portions 411 of two adjacent rows in the same first collecting electrode are staggered along the second direction Y, which is more conducive to collecting carriers and improves the uniformity and effectiveness of carrier collection.

[0117] In the embodiment of the present invention, the first contact portions 411 in two adjacent rows are end-to-end aligned along the second direction Y. Such an arrangement is beneficial for simplifying the manufacturing process of the first collecting electrode.

[0118] In an embodiment of the present invention, in at least one pair of adjacent first collecting electrodes 41 , the first contact portions 411 are staggered along the second direction Y. In some embodiments, in at least one pair of adjacent first collecting electrodes 41 , the first contact portions 411 are aligned along the second direction Y.

[0119] According to an embodiment of the present invention, in a pair of adjacent first collecting electrodes 41 , the first contact portions 411 are staggered along the second direction Y, which is more conducive to collecting carriers and improves the uniformity and effectiveness of carrier collection.

[0120] In the embodiment of the present invention, in a pair of adjacent first collecting electrodes 41 , the first contact portions 411 are end-to-end aligned along the second direction Y. This arrangement is beneficial for simplifying the manufacturing process of the first collecting electrodes.

[0121] To facilitate understanding of the specific applicability of the first and second collector electrodes provided by the present invention in a solar cell, a TBC cell is used as an example for detailed description below. The solar cell of the present invention may include a semiconductor substrate 10, a first doped conductive layer 21, a second doped conductive layer 22, a passivation layer 30, a plurality of first collector electrodes 41, and a plurality of second collector electrodes 42.

[0122] refer to Figure 4As shown, the solar cell is a TBC cell, in which the first doped conductive layer 21 can be a P-type doped polysilicon layer, and the second doped conductive layer 22 can be an N-type doped polysilicon layer, and the two are alternately arranged on the first surface of the semiconductor substrate 10. The solar cell may also include a first tunneling layer 51 and a second tunneling layer 52. The first tunneling layer 51 is located between the semiconductor substrate 10 and the first doped conductive layer 21, and forms a TOPCon structure with the first doped conductive layer 21. The second tunneling layer 52 is located between the semiconductor substrate 10 and the second doped conductive layer 22, and forms a TOPCon structure with the second doped conductive layer 22. The solar cell may further include another anti-reflection layer 60 located on a second surface of the semiconductor substrate 10 opposite the first surface.

[0123] The first collecting electrode 41 includes a plurality of first contact portions 411 and a first transmission portion 412. The plurality of first contact portions 411 pass through the passivation layer 30 and are electrically connected to the first doped conductive layer 21. The plurality of first contact portions 411 are spaced apart along the first direction S1. The first transmission portion 412 is disposed on a side of the first contact portion 411 away from the semiconductor substrate 10 and is in contact and connected with the plurality of first contact portions 411. The first transmission portion 412 extends along the first direction S1.

[0124] The second collector electrode 42 includes a plurality of second contact portions 421 and a second transmission portion 422. The plurality of second contact portions 421 pass through the passivation layer 30 to electrically connect to the second doped conductive layer 22. The plurality of second contact portions 421 are spaced apart along the first direction S1. The second transmission portion 422 is disposed on a side of the second contact portion 421 away from the semiconductor substrate 10 and is in contact and connected with the plurality of second contact portions 421. The second transmission portion 422 extends along the first direction S1. The specific configuration of the first collector electrode 41 and the second collector electrode 42 is the same as described above, so it will not be repeated. Of course, in other examples, the second collector electrode 42 may also adopt a traditional electrode structure, that is, the second collector electrode 42 is an integrated structure that directly passes through the passivation layer 30 and is electrically connected to the second doped conductive layer 22.

[0125] According to another embodiment of the present invention, a method for preparing a solar cell is also provided. The method can be used to prepare the solar cell provided in any of the above embodiments. Figure 3 As shown, the method for preparing a solar cell according to an embodiment of the present invention includes operations S101 to S104. It should be noted that the sequence numbers of S101 to S104 do not necessarily mean that these operations must be performed in sequence, and the sequence of these operations can be adjusted as needed.

[0126] In operation S101 , a first doped conductive layer 21 and a second doped conductive layer 22 are formed on a semiconductor substrate 10 .

[0127] In operation S102 , a passivation layer 30 is formed on the first doped conductive layer 21 and the second doped conductive layer 22 .

[0128] In operation S103, a plurality of first contact portions 411 are made on a side of the passivation layer 30 away from the first doped conductive layer 21, and a plurality of second contact portions 421 are made on a side of the passivation layer 30 away from the second doped conductive layer 22, wherein the plurality of first contact portions 411 respectively pass through the passivation layer 30 to contact the first doped conductive layer 21, and the plurality of second contact portions 421 pass through the passivation layer 30 to contact the second doped conductive layer 22.

[0129] In operation S104, a plurality of first transmission portions 412 extending along the first direction and spaced apart along the second direction are fabricated on the plurality of first contact portions 411, each first transmission portion 412 is electrically connected to the corresponding plurality of first contact portions 411 spaced apart along the first direction to form a first collecting electrode 41, and a plurality of second transmission portions 422 extending along the first direction and spaced apart along the second direction are fabricated on the plurality of second contact portions 421, each second transmission portion 422 is electrically connected to the corresponding plurality of second contact portions 421 spaced apart along the first direction to form a second collecting electrode 42.

[0130] According to an embodiment of the present invention, the present invention can improve the preparation method of the first collecting electrode and the second collecting electrode on the basis of the original preparation process of the first doped conductive layer, the second doped conductive layer and the passivation layer, and use high-temperature slurry to prepare multiple discontinuously distributed contact parts, thereby reducing the amount of high-temperature slurry used and reducing process costs while ensuring contact performance. At the same time, by differentially setting the sizes of the first contact part and the second contact part, the balance of carrier collection of the first doped conductive layer and the second doped conductive layer can be taken into account, thereby improving battery efficiency.

[0131] According to an embodiment of the present invention, before operation S101, the semiconductor substrate 10 may be subjected to surface treatment, such as texturing and / or polishing. For example, the silicon substrate is subjected to texturing to form a textured surface structure including a plurality of pyramids.

[0132] According to an embodiment of the present invention, the first doped conductive layer 21 and the second doped conductive layer 22 can be produced on the surface of a semiconductor substrate by combining diffusion, laser drilling, ion implantation and annealing, masking, etching and other technologies. Since the existing preparation processes in the art can be used and are not the key points of the present invention, they will not be described one by one.

[0133] According to an embodiment of the present invention, in operation S102, the passivation layer of the present invention can be a single layer or a multi-layer, and its specific material selection is the same as the previous article and will not be repeated here. The preparation method of the passivation layer can be specifically selected according to its material and structure, which can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering), etc.

[0134] For example, an aluminum oxide passivation layer is first deposited using ALD (atomic layer deposition), followed by PECVD to form one or more silicon nitride layers thereon. This is not limited to ALD and PECVD; other methods include APCVD, LPCVD, MOCVD, and PVD (e.g., evaporation and sputtering).

[0135] According to some embodiments of the present invention, the solar cell can be a double-sided contact cell, in which the first doped conductive layer 21 and the second doped conductive layer 22 are respectively located on the first surface and the second surface opposite to each other of the semiconductor substrate 10, and the passivation layer 30 can be respectively formed on the first doped conductive layer 21 and the second doped conductive layer 22; or, the solar cell can be a back contact cell, in which the first doped conductive layer 21 and the second doped conductive layer 22 are alternately arranged on the first surface, and the passivation layer 30 can be simultaneously formed on the first doped conductive layer 21 and the second doped conductive layer 22.

[0136] According to an embodiment of the present invention, in operation S103, a first contact portion 411 and a second contact portion 421 may be formed on the passivation layer using screen printing, and then sintered so that the electrode paste passes through the passivation layer 30 and contacts the first doped conductive layer 21 and the second doped conductive layer 22, respectively. The first contact portion 411 and the second contact portion 421 may be formed simultaneously or separately. Furthermore, the electrode paste may include metal particles such as silver, nickel, copper, and / or zinc.

[0137] According to an embodiment of the present invention, in operation S104, an electrode paste that is the same as or different from the first contact portion or the second contact portion can be printed on the first contact portion 411 and the second contact portion 421 to form the first transmission portion 412 and the second transmission portion 422. The first transmission portion 412 and the second transmission portion 422 can be manufactured simultaneously or separately. Further optionally, the electrode paste can include base metal particles, for example, a low-temperature silver-coated copper paste, a low-temperature copper paste, a low-temperature nickel paste, etc. The "low temperature" here can mean that the paste sintering temperature is below 300°C, especially below 250°C.

[0138] The above describes the preparation of the first and second collecting electrodes by printing and sintering, but this is not limiting. For example, the first and second contact portions can also be prepared by laser grooving the passivation layer and then electroplating, followed by printing the first and second transmission portions. In this case, using electroplating to prepare the seed layer helps reduce metal recombination and minimize battery efficiency loss.

[0139] According to an exemplary embodiment of the present invention, the present invention provides a photovoltaic assembly, comprising a plurality of the aforementioned solar cells connected into a solar cell string; and an encapsulation layer covering surfaces of the plurality of solar cells.

[0140] According to an embodiment of the present invention, the number of solar cells connected in series can be 4 to 80 or even more. Multiple solar cells can be formed into several battery strings, each battery string has the same number of solar cells, and the cells in the battery string are connected in series. The battery strings can be connected in series or in parallel.

[0141] According to embodiments of the present invention, the encapsulation layer may include a backsheet, an encapsulation film, and a glass panel to enhance the stability of the solar cell string. The glass panel is located on the front of the solar cell string, while the backsheet is located on the back of the solar cell string, both providing protection. The adhesive film, which serves as a bonding and fixing agent between the solar cell string, the glass panel, and the backsheet, must be made of a transparent material.

[0142] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A solar cell, characterized in that: include: a semiconductor substrate comprising a first surface and a second surface opposite to each other; and a plurality of first collecting electrodes disposed on the first surface of the semiconductor substrate, the plurality of first collecting electrodes extending along a first direction and spaced apart along a second direction; the first collecting electrodes comprising a plurality of first contact portions and first transmission portions, the plurality of first contact portions being spaced apart along the first direction; the first transmission portion being disposed on a side of the first contact portion away from the semiconductor substrate and being in contact with and connected to the plurality of first contact portions, the first transmission portion extending along the first direction; Among them, in at least one pair of adjacent first collecting electrodes, a spacing between at least one pair of adjacent first contact portions in the first direction is less than or equal to a spacing between the pair of adjacent first collecting electrodes in the second direction.

2. The solar cell according to claim 1, wherein Also includes: A first doped conductive layer is disposed on the first surface of the semiconductor substrate; a passivation layer, disposed on a side of the first doped conductive layer away from the semiconductor substrate; Among them, the multiple first collecting electrodes are arranged on a side of the passivation layer away from the first doped conductive layer; the multiple first contact portions are electrically connected to the first doped conductive layer through the passivation layer; and the conductivity type of the first doped conductive layer is the same as the conductivity type of the semiconductor substrate.

3. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, a distance between at least one pair of adjacent first contact portions in the first direction is less than or equal to 1.5 mm; And / or, a distance between at least one pair of adjacent first collecting electrodes in the second direction is 0.5-1.5 mm.

4. The solar cell according to claim 1 or 2, characterized in that In at least one pair of adjacent first collecting electrodes, a ratio of a distance between at least one pair of adjacent first contact portions in the first direction to a distance between the pair of adjacent first collecting electrodes in the second direction is less than or equal to 0.

8.

5. The solar cell according to claim 2, wherein The solar cell further comprises: a plurality of second collecting electrodes, arranged on the first surface and alternately spaced with the plurality of first collecting electrodes, or arranged on the second surface, the plurality of second collecting electrodes extending along the first direction and spaced along the second direction; the second collecting electrode comprising a plurality of second contact portions and a second transmission portion, the plurality of second contact portions being spaced along the first direction; the second transmission portion being arranged on a side of the second contact portion away from the semiconductor substrate and in contact with and connected to the plurality of second contact portions, the second transmission portion extending along the first direction; In at least one of the first collecting electrodes, a distance between at least one pair of adjacent first contact portions is greater than a distance between at least one pair of adjacent second contact portions in at least one of the second collecting electrodes.

6. The solar cell according to claim 5, characterized in that In at least one of the first collecting electrodes, a distance between at least one pair of adjacent first contact portions is 0.3 to 1.5 mm; In at least one of the second collecting electrodes, a distance between at least one pair of adjacent second contact portions is 0.2-1.2 mm.

7. The solar cell according to claim 5, characterized in that In the first direction, the length of the first contact portion and / or the length of the second contact portion is 0.2-3 mm.

8. The solar cell according to claim 5, characterized in that In at least one of the first collecting electrodes, a ratio of a length of at least one of the first contact portions along the first direction to a spacing between another first contact portion adjacent to the first contact portion is smaller than a ratio of a length of at least one of the second contact portions along the first direction to a spacing between another second contact portion adjacent to the second contact portion in at least one of the second collecting electrodes.

9. The solar cell according to claim 5, characterized in that In at least one of the first collecting electrodes, a ratio of a length of at least one of the first contact portions along the first direction to a spacing between another first contact portion adjacent to the first contact portion, or in at least one of the second collecting electrodes, a ratio of a length of at least one of the second contact portions along the first direction to a spacing between another second contact portion adjacent to the second contact portion is 0.3 to 3.

10. The solar cell according to claim 1, wherein The first contact portion includes at least one of silver, nickel, titanium and a transparent conductive oxide; The first transmission portion includes at least one of copper, aluminum, silver-clad copper, and silver-copper alloy.

11. The solar cell according to claim 1, wherein The solar cell further includes at least one first welding point disposed on the first surface and connected to at least one first collecting electrode. Along the first direction, the length of the first welding point is greater than the spacing between adjacent first contact portions.

12. The solar cell according to claim 1, wherein In at least one of the first collecting electrodes, the middle position of the first transmission part has a disconnected part arranged at intervals along the first direction, the disconnected part and / or the end of the first transmission part has a third contact part, and the length of the third contact part is different from that of the first contact part.

13. The solar cell according to claim 1, wherein Along the second direction, the width of the first contact portion along the second direction is smaller than the width of the first transmission portion along the second direction; And / or, along the second direction, a ratio of a width of the first transmission portion along the second direction to a width of the first contact portion along the second direction is 0.8 to 2.5; And / or, a width of the first contact portion along the second direction is 10-50 μm, and a width of the first transmission portion along the second direction is 30-100 μm.

14. The solar cell according to claim 1, wherein In at least one of the first transmission parts, a plurality of first contact parts electrically connected to the first transmission part are distributed in at least two rows along the second direction; Each row includes a plurality of first contact portions arranged along the first direction, and the first contact portions of two adjacent rows are staggered along the second direction.

15. The solar cell according to claim 1, wherein In at least one pair of adjacent first collecting electrodes, the first contact portions are staggered along the second direction.

16. A photovoltaic module, characterized in that: include: A plurality of solar cells according to any one of claims 1 to 15, connected into a solar cell string; And, an encapsulation layer covers the surfaces of the plurality of solar cells.

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