Solar cell, cell module and photovoltaic system

Abstract

Solar cell, comprehensive: a silicon substrate, having a first surface and a second surface opposite each other; first doped layers arranged on the first surface, wherein the first doped layers each have several first predetermined zones; several second doped layers arranged on the first predetermined zones, the second doped layers being spaced apart from each other; a first passivation film layer, arranged on the second doped layers and the first doped layers; and Several first solder joints arranged on the first passivation film layer, wherein orthogonal projections of the first solder joints onto the first doped layers overlap at least partially with orthogonal projections of the second doped layers onto the first doped layers.

Description

Reference to the associated registration

[0001] The disclosure claims the priority and benefits of Chinese patent applications No. 202311238243.4, filed with the China National Intellectual Property Administration on September 22, 2023, as well as No. 202420802407.5 and No. 202420798601.0, filed with the China National Intellectual Property Administration on April 17, 2024, as incorporated herein in their entirety by reference. Technical field

[0002] The disclosure relates to the technical field of solar cells and specifically to a solar cell, a cell module and a photovoltaic system. background

[0003] Currently, all types of solar cells (such as topcon solar cells, HJT solar cells, and back-contact solar cells) are coated with doped layers on which fingers and busbars are arranged. The fingers penetrate a passivation film layer to make contact with the doped layers for current collection. The busbars are connected to the fingers to collect the current from the fingers. To connect two solar cells together, the cells must be equipped with solder pads so they can be soldered to a solder strip. The solder pads are typically placed on the passivation film layer. Summary

[0004] The disclosure concerns a solar cell, a cell module, and a photovoltaic system.

[0005] The solar cell of an example from Revelation includes: a silicon substrate, having a first surface and a second surface opposite each other; first doped layers arranged on the first surface, wherein the first doped layers each have several first predetermined zones; several second doped layers arranged on the first predetermined zones, the second doped layers being spaced apart from each other; a first passivation film layer, arranged on the second doped layers and the first doped layers; and Several first solder joints arranged on the first passivation film layer, wherein orthogonal projections of the first solder joints onto the first doped layers overlap at least partially with orthogonal projections of the second doped layers onto the first doped layers.

[0006] The disclosure further provides for a cell module. The cell module comprises several solar cells.

[0007] The disclosure further provides for a photovoltaic system. The photovoltaic system comprises the aforementioned cell module.

[0008] Further aspects and benefits of the revelation are partly set out in the following description and will become apparent in the following description or can be learned through the practical application of the revelation. Brief description of the drawings Fig. 1 is a schematic module diagram of a photovoltaic system according to an example of the disclosure; Fig. Figure 2 is a schematic module diagram of a cell module according to an example from the revelation; Fig. Figure 3 is a schematic structural diagram of a solar cell according to an example from the revelation; Fig. Figure 4 is another schematic structural diagram of a solar cell according to an example from the revelation; Fig. 5 is yet another schematic structural diagram of a solar cell according to an example from the revelation; Fig. Figure 6 is another schematic structural diagram of a solar cell according to an example from the revelation; Fig. Figure 7 is a schematic diagram of a planar structure of a solar cell according to an example from the revelation; Fig. Figure 8 is a schematic diagram of a section along line VI-VI of a back-contact cell in Fig. 7; Fig. Figure 9 is a schematic diagram of another section along line VI-VI of a back-contact cell in Fig. 7; Fig. 10 is a schematic diagram of yet another section along line VI-VI of a back-contact cell in Fig. 7; Fig. 11 is a schematic diagram of yet another section along line VI-VI of a back-contact cell in Fig. 7; Fig. Figure 12 is a schematic diagram of another planar structure of a solar cell according to an example from the revelation; Fig. 13 is a schematic diagram of a section along line IX-IX of a back-contact cell in Fig. 12; Fig. 14 is a schematic diagram of a section along line XX of a back-contact cell in Fig. 12; Fig. 15 is a schematic diagram of a further section along line IX-IX of a back-contact cell in Fig. 12; Fig. 16 is a schematic diagram of a further section along line XX of a back-contact cell in Fig. 12; and Fig. Figure 17 is a schematic diagram of yet another planar structure of a solar cell according to an example from the revelation. Detailed description of the embodiments

[0009] To clarify the objectives, technical solutions, and benefits of the disclosure, it will be described in more detail below with reference to the accompanying drawings and examples. The examples described with reference to the accompanying drawings serve only to illustrate the disclosure and are intended solely to explain it without limiting it. Furthermore, it should be noted that the specific examples described here serve only to clarify the disclosure and not to limit it.

[0010] In describing the disclosure, it should be noted that the orientation and position relationships indicated by the terms "length", "width", "above", "below", "top", "bottom", "transverse", "longitudinal", etc. are based on orientation or position relationships shown in the accompanying drawings, serve only to facilitate and simplify the description of the disclosure, and do not indicate or imply that a named device or element must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be interpreted as a limitation of the disclosure.

[0011] Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be interpreted as indicating or implying their relative significance or implicitly specifying the number of technical features listed. Thus, features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the disclosure, "a multitude of" means two or more, unless expressly stated otherwise.

[0012] In the description of the disclosure, it should be noted that the terms "fasten," "connect," and "connected" are to be interpreted broadly unless expressly stated and defined otherwise. They may, for example, denote a fixed connection, a detachable connection, or an integral connection; a mechanical connection, an electrical connection, or mutual communication; a direct connection or an indirect connection via an intermediary; or communication between the interiors of two elements or an interaction between two elements. For those skilled in the art, the specific meanings of the aforementioned terms in the disclosure are understandable according to the specific circumstances.

[0013] In the disclosure, a case of a first feature being “on” or “under” a second feature, unless otherwise specified and limited, may include direct contact between the first and second features, or it may include a case in which the first and second features are not in direct contact but are connected via another feature in between. Furthermore, a case in which the first feature is “on,” “above,” and “on an upper part” of the second feature may include a case in which the first feature is directly above and obliquely above the second feature, or it may simply state that the horizontal height of the first feature is greater than that of the second feature.A case in which the first feature is “under”, “below”, and “on a lower part” of the second feature includes a case in which the first feature is directly below and obliquely below the second feature, or simply indicates that the horizontal height of the first feature is less than that of the second feature.

[0014] The following section reveals many different examples or cases to implement various structures of revelation. To simplify the revelation, the components and arrangements of specific cases are described below. It is clear that these instances are for illustrative purposes only and are not intended to limit the revelation. Furthermore, reference numbers and / or reference letters may be repeated in different instances of revelation for the sake of simplicity and clarity and do not indicate relationships between the various examples and / or arrangements discussed. In addition, revelation includes instances of various specific procedures and materials. However, experts in this field may be aware of the application of other procedures and / or the use of other materials.

[0015] With reference to Fig. 1-2 A photovoltaic system 1000 of an example of disclosure can comprise a cell module 200 of an example of disclosure. The cell module 200 of the example of disclosure can comprise multiple cell strings. Each of the cell strings can comprise multiple solar cells 100 of an example of disclosure. In the disclosure, multiple solar cells 100 of the cell module 200 can be sequentially connected in series by means of a solder band to form a cell string. Each cell string of the cell module 200 can be connected in series, in parallel, or in a series-parallel configuration to output currents in a convergent manner. For example, all cell strings can be interconnected by means of a busbar.

[0016] With reference to Fig. 3 and Fig. 4 The solar cell 100 of the example can comprise a silicon substrate 10, first doped layers 20, second doped layers 30, a first passivation film layer 40 and first solder joints 50.

[0017] The silicon substrate 10 has a first surface 11 and a second surface 12, which are opposite each other. The first doped layers 20 are arranged on the first surface 11. The first doped layers 20 each have several first predetermined zones 201. The several second doped layers 30 are arranged on the first predetermined zones 201 and the second doped layers 30 are spaced apart from each other.

[0018] The first passivation film layer 40 is arranged on the second doped layers 30 and the first doped layers 20. In particular, the first passivation film layer 40 can cover the entire first doped layers 20 and second doped layers 30 (that is, the first passivation film layer 40 covers the second doped layers 30 and areas of the first doped layers 20 that are not covered by the second doped layers 30).

[0019] The first solder joints 50 can be located on the first passivation film layer 40. Orthogonal projections of the first solder joints 50 onto the first doped layers 20 overlap at least partially with orthogonal projections of the second doped layers 30 onto the first doped layers 20. That is, the first solder joints 50 are located at least partially above the second doped layers 30.

[0020] In other words, the first solder joints 50 overlap at least partially the second doped layers 30 in one thickness direction of the solar cell 100. It should be noted that the “orthogonal projection” in the disclosure refers to an orthogonal projection in the thickness direction of the solar cell 100, which can be referenced for understanding when a similar description is given below.

[0021] In the prior art, the tensile force between a doped layer and a passivation film layer below a solder joint is weak, and the solder joint tends to detach due to insufficient tensile force during soldering.

[0022] In the solar cell of the example disclosed, the first predetermined zones 201 of the first doped layers 20 are provided with the second doped layers 30, and the second doped layers 30 are covered with the first passivation film layer 40. The orthogonal projections of the first solder joints 50 onto the first doped layers 20 overlap at least partially with the orthogonal projections of the second doped layers 30 onto the first doped layers 20. In this way, the second doped layers 30 are arranged on the first doped layers 20, so that a bond tensile force with the first passivation film layer 40 can be improved.The first solder joints 50 are arranged above the second doped layers 30 (that is, the orthogonal projections of the first solder joints 50 onto the first doped layers 20 overlap at least partially with the orthogonal projections of the second doped layers 30 onto the first doped layers 20), so that the solder tensile force of the first solder joints 50 can be effectively improved during soldering. Furthermore, the first solder joints 50 can be effectively protected against delamination during soldering, and the soldering reliability can be improved.

[0023] In particular, the solar cell 100 in the disclosure may specifically be a back-contact cell, a top-con solar cell, an HJT solar cell or any other solar cell which is provided with the first doped layers 20 and has solder joints on the first doped layers 20, which is not specifically limited herein.

[0024] In some embodiments, the polarity of the second doped layers 30 is opposite to that of the first doped layers 20. The roughness of the surfaces 301 of the second doped layers 30, which are in contact with the first passivation film layer 40, is greater than that of the surfaces 202 of the first doped layers 20, which are in contact with the first passivation film layer 40.

[0025] In this way, the roughness of the surfaces 301 of the second doped layers 30, which are in contact with the first passivation film layer 40, is greater than that of the surfaces 202 of the first doped layers 20, which are in contact with the first passivation film layer 40, so that the bond tensile force between the first passivation film layer 40 and the second doped layers 30 can be significantly greater than that between the first passivation film layer 40 and the first doped layers 20. A solder tensile force of the first solder joints 50 during soldering can be effectively improved, and furthermore, the first solder joints 50 can be effectively protected from delamination during soldering.

[0026] In particular, the first doped layers can be 20 and the second doped layers can be 30 P-type doped layers or N-type doped layers, respectively, as long as the polarity of the second doped layers is opposite to that of the first doped layers. For example, in some embodiments, the first doped layers can be 20 P-type polysilicon layers, P-type amorphous silicon layers, or P-type microcrystalline silicon layers, which are not specifically limited herein.

[0027] Similarly, the second doped layers can be 30 N-type doped polysilicon layers, N-type doped amorphous silicon layers, or N-type doped microcrystalline silicon layers, which are not specifically limited in this respect.

[0028] In some embodiments, the polarity of the second doped layers 30 is opposite to that of the first doped layers 20, and the first doped layers 20 are P-type doped layers, while the second doped layers 30 are N-type doped layers.

[0029] In some embodiments, a tunnel oxide layer or an intrinsic amorphous silicon layer (not shown in the figure) can be arranged between the first doped layers 20 and the silicon substrate 10. In particular, if the solar cell is a top-con solar cell or a back-contact cell, a tunnel oxide layer can be arranged between the first doped layers 20 and the silicon substrate 10. If the solar cell is an HJT solar cell, an intrinsic amorphous silicon layer can be arranged between the first doped layers 20 and the silicon substrate 10.

[0030] With reference to Fig. 3 In some embodiments, the first predetermined zones 201 are part of the surfaces of the first doped layers 20 facing away from the silicon substrate 10, and the second doped layers 30 are arranged on the first predetermined zones 201 and are all located above the first doped layers 20.

[0031] In particular, as in Fig. Figure 3 shows the first predetermined zones 201 as sub-zones of the surfaces of the first doped layers 20 facing away from the silicon substrate 10, and are essentially planar zones. In this case, the second doped layers 30 are arranged directly on top of the first doped layers 20 and are all located on the second doped layers 30.

[0032] With reference to Fig. 4 In some other examples, the first predetermined zones 201 can be the first recessed depressions 210 formed on the first doped layers 20, and the second doped layers 30 are stacked in the first recessed depressions 210. The first solder joints 50 overlap at least partially the second doped layers 30 in one thickness direction of the solar cell 100.

[0033] It is understood that in the revelation the second doped layers 30 may be arranged in the first recessed depressions 210 as follows: All parts of the first doped layers 30 may be completely contained in the first recessed depressions 210, or the first doped layers 30 may extend partially out of the first recessed depressions 210 in the thickness direction, which is not specifically limited here.

[0034] In some embodiments, the depth of the first recessed depressions can be 210.5 nm to 400 nm.

[0035] In this way, a poor stress reinforcement effect caused when the thickness of the second doped layers 30 is too small due to an insufficient depth of the first recessed wells 210 can be effectively avoided, or an increase in costs caused when the thickness of the second doped layers 30 is too large due to an excessive depth of the first recessed wells 210 can be avoided.

[0036] In particular, the depth of the first recessed depressions may be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or any numerical value between 5 nm and 400 nm, which is not specifically limited herein.

[0037] With reference to Fig. 5 and Fig. 6. In some embodiments, the solar cell 100 may further comprise first insulating layers 60. The first insulating layers 60 may be arranged between the first doped layers 20 and the second doped layers 30 in order to isolate the first doped layers 20 from the second doped layers 30.

[0038] In this way, the second doped layers 30 are isolated from the first doped layers 20 by the first insulating layers 60, thus preventing the second doped layers from coming into direct contact with the first doped layers. At the same time, a passivation effect of the first doped layers 20 can be ensured.

[0039] In particular, as in Fig. Figure 5 shows that in some embodiments, the first insulating layers 60 are arranged directly on the surfaces of the first doped layers 20 and cover the first doped layers 20, and the second doped layers 30 can cover the first insulating layers 60. As shown in Fig. As shown in Figure 6, in some embodiments the first insulating layers 60 can be arranged on the inner walls of the first recessed depressions 210. That is, the inner walls of the first recessed depressions 210 are provided with the first insulating layers 60, and the second doped layers 30 can cover the first insulating layers 60 in a stacked manner.

[0040] It is understood, of course, that in some embodiments the first insulating layers 60 need not be arranged to isolate the first doped layers 20 from the second doped layers 30, and that only metal grid lines that are in contact with the first doped layers 20 in the solar cell 100 need to be arranged so that they do not have contact with the second doped layers 30, which is not specifically limited herein.

[0041] In some embodiments, the thickness of the first insulating layers 60 can be greater than 2 nm. This avoids increased process difficulty due to insufficient thickness of the first insulating layers 60.

[0042] Furthermore, in some embodiments, the first insulating layer 60 may comprise at least one silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer.

[0043] In particular, in the examples, the first insulation layers 60 may or may not have a tunneling function and may or may not be an insulating layer, which is not specifically limited here. A specific film layer can be selected according to the different cell types.

[0044] For example, if the cell is a top-con solar cell or a back-contact cell, the first insulating layer 60 can be at least one silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer. The first insulating layer 60 may or may not have a tunneling function.

[0045] If the cell is an HJT solar cell, the first insulating layer 60 can be an intrinsic amorphous silicon layer. It is understood that a specific selection of the first insulating layers 60 is illustrated here only and cannot be understood as a limitation of the disclosure.

[0046] As in the Fig. 3, Fig. 4, Fig. 5 to Fig. As shown in Figure 6, in some embodiments the area of ​​orthogonal projections of the first predetermined zones 201 onto the silicon substrate 10 is greater than or equal to that of orthogonal projections of the first solder joints 50 onto the silicon substrate 10, and the orthogonal projections of the first solder joints 50 onto the first doped layers 20 are located entirely within the first predetermined zones 201. That is, the first solder joints 50 are located entirely above the second doped layers 30 in the thickness direction of the solar cell 100. If the first predetermined zones 201 are the first recessed wells 210, the orthogonal projections of the first solder joints 50 onto the first doped layers 20 are located entirely within the first recessed wells 210.

[0047] In this way, the first solder joints 50 are completely located in the first predetermined zones 201, and the entire lower sections of the first solder joints 50 are all provided with the second doped layers, so that a soldering tensile force at the first solder joints 50 can be increased to the highest degree and the soldering reliability can be ensured.

[0048] In particular, in the examples, an area of ​​the first predetermined zones 201 may preferably correspond exactly to the area of ​​the orthogonal projections of the first solder joints 50 or be slightly larger than the area of ​​the orthogonal projections of the first solder joints 50.

[0049] In some embodiments, the area of ​​the orthogonal projections of the first solder joints 50 onto the first doped layers 20 can, of course, also be larger than that of the orthogonal projections of the second doped layers 30 onto the first doped layers 20 (i.e., the area of ​​the first predetermined zones 201). For example, a single first solder joint 50 can correspond to a plurality of second doped layers 30. In this case, the first solder joint 50 can completely cover the second doped layers 30. In this case, the ratio of an overlapping area of ​​the second doped layers 30 and the first solder joint 50 to a total area of ​​the first solder joint 50 can be greater than 20%, thus avoiding insufficient soldering force.

[0050] Furthermore, in some embodiments, the first solder joints 50 may be located on upper sections of the first passivation film layer 40, or may be partially embedded in the first passivation film layer 40, or may at least partially penetrate the first passivation film layer 40 to make contact with the second doped layers 30. When the first solder joints 50 are in contact with the second doped layers 30, the first insulating layers 60 may be arranged to insulate the first doped layers 20 from the second doped layers 30, without any particular limitation herein.

[0051] In some embodiments, the thickness of the second doped layer can range from 30.5 nm to 400 nm.

[0052] In this way, a poor stress-intensification effect due to insufficient thickness of the second doped layer 30 can be effectively avoided, or increased process difficulty due to insufficient thickness of the second doped layer 30 can be avoided. At the same time, cost increases due to excessive thickness of the second doped layer 30 can be avoided.

[0053] In particular, the thickness of the second doped layers can be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or any numerical value between 5 nm and 400 nm, which is not specifically limited herein.

[0054] In some embodiments, the first passivation film layer 40 may comprise at least one silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer and a transparent conductive oxide (TCO) film layer.

[0055] In particular, in the examples, the type of first passivation film layer 40 can also be selected according to the different cell types. For example, if the cell is a top-con solar cell or a back-contact cell, the first passivation film layer 40 can be at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer.

[0056] If the cell is an HJT solar cell, the first passivation film layer 40 can be a TCO film layer, which is not specifically limited herein. It is understood that any specific selection of the first passivation film layer 40 is illustrated herein only and cannot be understood as a limitation of the disclosure.

[0057] With reference to the Fig. 7-13 The solar cell 100 can, in some embodiments, further comprise third doped layers 70, a second passivation film layer 80, and several second solder joints 90. The polarity of the third doped layers 70 is opposite to that of the first doped layers 20.

[0058] As in the Fig. As shown in Figures 8-11, in some embodiments the first doped layers 20 can be arranged on the first surface 11, the third doped layers 70 can be arranged on the second surface 12, the second passivation film layer 80 can be arranged on the third doped layers 70, and the second solder joints 90 can be arranged on the second passivation film layer 80. In this case, the solar cell 100 is a double-sided solar cell, for example, a Topcon solar cell, an HJT solar cell, etc.

[0059] Similarly, the second passivation film layer 80 in the disclosure can comprise at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer and a TCO film layer.

[0060] As in Fig. 12, Fig. 13, Fig. 14, Fig. 15 to Fig. As shown in Figure 16, in some embodiments the first doped layers 20 and the third doped layers 70 can all be arranged on the first surface 11, the first passivation film layer 40 can be arranged on the first doped layers 20, the second doped layers 30, and the third doped layers 70, the second solder joints 90 can be arranged on the first passivation film layer 40, and the second passivation film layer 80 can be arranged on the second surface 12. In this case, if the solar cell 100 is a back-contact cell, the first surface 11 is the back side of the cell and the second surface 12 is the front side of the cell.

[0061] In the example of the disclosure, the second doped layers 30 in the solar cell 100 can be obtained by partially removing winding layers formed on the first doped layers 20 in a process for forming the aforementioned third doped layers 70, and the roughness of the second doped layers 30 can be controlled by controlling the deposition temperature and time or by etching. In some embodiments, the second doped layers 30 can, of course, also be obtained directly by deposition. Similarly, the roughness of the second doped layers 30 can also be controlled by controlling the deposition temperature and time or by etching, which is not specifically limited herein.

[0062] It is understood that if the solar cell 100 is a double-sided solar cell, the first passivation film layer 40 is provided with several first fingers (not shown in the figure) and the first fingers penetrate the first passivation film layer 40 to come into contact with the first doped layer 20; and the second passivation film layer 80 is provided with several second fingers (not shown in the figure) and the second fingers penetrate the second passivation film layer 80 to come into contact with the third doped layer 70. The double-sided solar cell is further provided with a first busbar (not shown in the figure) in cross-contact with the first fingers and a second busbar (not shown in the figure) in cross-contact with the second fingers.The first solder pads 50 can be located on the first busbar, which may be situated on the first passivation film layer 40, or partially embedded in or penetrating the first passivation film layer 40 to make contact with the second doped layer 30 below the first passivation film layer 40. The first solder pads 50 are configured to be soldered to a solder strip. Similarly, the second solder pads 90 can be located on the second busbar, which may be situated on the second passivation film layer 80, or partially embedded in or penetrating the second passivation film layer 80. The second solder pads 90 are also configured to be soldered to the solder strip.

[0063] If the solar cell 100 is a back-contact cell, the first passivation film layer 40 is provided with third fingers (not shown in the figure) and fourth fingers (not shown in the figure). The third fingers penetrate the first passivation film layer 40 to make contact with the first doped layer 20. The fourth fingers penetrate the first passivation film layer 40 to make contact with the third doped layer 70.

[0064] If the solar cell 100 is a back-contact cell, the following two cases can occur: Case one: As in Fig. As shown in Figure 12, in some embodiments several first doped layers 20 and several third doped layers 70 can be arranged sequentially and alternately in a first direction on the first surface 11, and the first doped layers 20 and the third doped layers 70 all extend in a second direction. The second direction intersects the first direction. The second direction and the first direction can be a longitudinal direction and a transverse direction of the solar cell 100, respectively. As shown in Figure 12, in some embodiments several first doped layers 20 and several third doped layers 70 can be arranged sequentially and alternately in a first direction, and the first doped layers 20 and the third doped layers 70 all extend in a second direction. The second direction intersects the first direction. The second direction and the first direction can be a longitudinal direction and a transverse direction of the solar cell 100, respectively. Fig. As can be seen in Figure 12, in the example the first doped layers 20 and the third doped layers 70 are continuous doped layers in the second direction and arranged sequentially and alternately in the first direction.

[0065] The back contact cell may or may not contain a busbar. If a busbar is present, the cell comprises multiple third busbars (not shown in the figure) and multiple fourth busbars (not shown in the figure). The multiple third busbars and the multiple fourth busbars are arranged alternately in the second direction, with the third fingers connected to the third busbars and disconnected from the fourth busbars, and the fourth fingers connected to the fourth busbars and disconnected from the third busbars. The first solder points 50 are located on and connected to the third busbars. The second solder points 90 are located on and connected to the fourth busbars. The multiple first solder points 50 may be arranged in one direction of extension of the third busbars. The multiple second solder points 90 may be arranged in one direction of extension of the fourth busbars.

[0066] If the busbar is not present, the first solder points 50 and the second solder points 90 can be located directly within a cover zone of the cell's solder tape. For example, the first solder points 50 can be located at the break points of the third fingers, and the second solder points 90 can be located at the break points of the fourth fingers. In this way, the fingers can be directly connected to the solder points via the solder tape, without the busbars. It is understood that in this case, the solder tape connected to the first solder points 50 can be electrically connected to all third fingers, and the solder tape connected to the second solder points 90 can be electrically connected to all fourth fingers.In some embodiments, the third fingers may of course not be separated from the fourth fingers, and the third fingers and the fourth fingers are insulated from the busbar or solder strip with opposite polarity by insulating paste, which is not specifically limited herein.

[0067] Case two: As in Fig. As shown in Figure 17, in some embodiments the first doped layers 20 can comprise several first doped sublayers 21 and several second doped sublayers 22, and the third doped layers 70 can comprise several third doped sublayers 71 and several fourth doped sublayers 72. The several first doped sublayers 21 and the several third doped sublayers 71 are arranged sequentially and alternately on the first surface 11 in the first direction and extend in the second direction.The multiple second doped sublayers 22 and the multiple fourth doped sublayers 72 are arranged sequentially and alternately on the first surface 11 in the second direction and extend in the first direction. The first doped sublayers 21 are separated from the fourth doped sublayers 72 and make contact with the second doped sublayers 22, and the third doped sublayers 71 are separated from the second doped sublayers 22 and make contact with the fourth doped sublayers 72. The second doped sublayers 22 each have multiple first predetermined zones 201. The multiple first predetermined zones 201 are arranged at a distance from each other in the second direction. A number of first solder joints 50 can correspond to a number of first predetermined zones 201.In this case, the first solder joints 50 can be arranged above the second doped sublayers 22 and the second solder joints 90 can be arranged above the fourth doped sublayers 72.

[0068] In particular, it is understandable that the first doped sublayers 21 and the second doped sublayers 22 together form the first doped layers 20 in a comb shape, and that the third doped sublayers 71 and the fourth doped sublayers 72 together form the third doped layers 70 in a comb shape. The first doped sublayers 21 and the second doped sublayers 22 can be formed by the same process. The third doped layers 71 and the fourth doped sublayers 72 can be formed by the same process.

[0069] Furthermore, in the examples in the first direction, the length of the first solder joints 50 is greater than that of the second doped layers 30, and the ratio of the length of the first solder joints 50 over the second doped layers 30 to the total length of the first solder joints 50 is greater than or equal to 20%.

[0070] In this way, if the length of the first solder joints 50 in the first direction is large, the ratio of the length (i.e., a length of overlapping parts between the orthogonal projections of the first solder joints 50 in the thickness direction and the second doped layers 30) of the first solder joints 50 over the second doped layers 30 to the total length of the first solder joints 50 is set to greater than or equal to 20%, so that a solder pull force of the first solder joints 50 can be effectively ensured and an insufficient solder pull force can be avoided.

[0071] Preferably, in order to ensure the solder pull force of the first solder joints 50, the ratio of the length of the first solder joints 50 over the second doped layers 30 to the total length of the first solder joints 50 is greater than or equal to 50% in the examples.

[0072] In some embodiments, the ratio of the area of ​​the orthogonal projections of the second doped layers 30 onto the second doped sublayers 22 to the area of ​​the second doped sublayers 22 is less than 50%. This avoids the situation where large recombination losses occur due to an excessive area ratio of the second doped layers 30, because the second doped layers 30 readily recombine with the second doped sublayers 22.

[0073] In particular, in the examples, the case where “a ratio of an area of ​​orthogonal projections of the second doped layers 30 onto the second doped sublayers 22 to an area of ​​the second doped sublayers 22 is less than 50%” can be a case where a ratio of an area of ​​all second doped layers 30 on a single second doped sublayer 22 to an area of ​​the single second doped sublayer 22 is less than 50%, or a case where a ratio of the sum of the areas of all second doped layers 30 on the entire back-contact cell to the sum of the areas of all second doped sublayers 22 is less than 50%, which is not specifically limited here. The first case is preferred.

[0074] Furthermore, as in Fig. As shown in Figure 17, in the examples in the first direction the distance between two adjacent first solder joints is 50.3 mm to 40 mm.

[0075] In this way, the distance between the two adjacent first solder joints 50 is set so that it lies within a rational range, allowing the first solder joints 50 to be located essentially within a rational spacing range and, furthermore, enabling the provision of an identical second doped sublayer 22 with a sufficient number of first solder joints 50. Thus, hollow soldering during soldering of the solder strip can be avoided and soldering reliability can be ensured.

[0076] In particular, in the examples, the distance between the two adjacent first solder points 50 can be, for example, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm or any numerical value between 3 mm and 40 mm, which is not specifically limited herein.

[0077] In the examples, the third doped layers 70 can each have several second predetermined zones 701. The solar cell 100 can further comprise fourth doped layers 110. The fourth doped layers 110 are arranged on the second predetermined zones 701. The multiple fourth doped layers 110 are arranged at a distance from each other.

[0078] As in Fig. 9 and Fig. 11 shown, in a case where the third doped layers 70 are arranged on the second surface 12, the second passivation film layer 80 covers the third doped layers 70 and the fourth doped layers 110, and orthogonal projections of the second solder joints 90 onto the third doped layers 70 overlap at least partially with orthogonal projections of the fourth doped layers 110 onto the third doped layers 70 (that is, the second solder joints 90 overlap at least partially the fourth doped layers 110 in the thickness direction of the solar cell 100).

[0079] As in Fig. 14 and Fig. Figure 16 shows that in a case where the third doped layers 70 are arranged on the first surface 11, the first passivation film layer 40 covers the first doped layers 20, the second doped layers 30, the third doped layers 70 and the fourth doped layers 110, and the orthogonal projections of the second solder joints 90 onto the third doped layers 70 overlap at least partially with the orthogonal projections of the fourth doped layers 110 onto the third doped layers 70 (that is, the second solder joints 90 overlap at least partially the fourth doped layers 110 in the thickness direction of the solar cell 100).

[0080] In this way, the tensile force of the second solder joints 90 can be effectively improved during soldering, while at the same time the tensile force of the first solder joints 50 can be increased during soldering, and the detachment of the second solder joints 90 during soldering can be effectively prevented.

[0081] In the examples, the polarity of the fourth doped layer 110 is opposite to that of the third doped layer 70.

[0082] In a case where the third doped layers 70 are arranged on the second surface 12, the roughness of the surfaces 111 of the fourth doped layers 110, which are in contact with the second passivation film layer 80, is greater than that of the surfaces 702 of the third doped layers 70, which are in contact with the second passivation film layer 80.

[0083] In a case where the third doped layers 70 are arranged on the first surface 11, the roughness of the surfaces 111 of the fourth doped layers 110, which are in contact with the first passivation film layer 40, is greater than that of the surfaces 702 of the third doped layers 70, which are in contact with the first passivation film layer 40.

[0084] In this way, the set roughness can further improve the tensile strength of the second solder joints 90 during soldering.

[0085] With reference to Fig. 14 In some embodiments, the second predetermined zones 701 are part of the surfaces of the third doped layers 70 that face away from the silicon substrate 10, and the fourth doped layers 110 are arranged on the second predetermined zones 701 and are all located above the third doped layers 70.

[0086] In particular, as in Fig. Figure 14 shows the second predetermined zones 701 as sub-zones of the surfaces of the third doped layers 70, which face away from the silicon substrate 10, and are essentially planar zones. In this case, the fourth doped layers 110 are arranged directly on the third doped layers 70 and are all located on the fourth doped layers 110.

[0087] With reference to Fig. 16 In some other examples, the second predetermined zones 701 can be second recessed depressions 701 formed on the third doped layers 70, and the fourth doped layers 110 are stacked in the second recessed depressions 701. The first solder joints 50 overlap at least partially the fourth doped layers 110 in the thickness direction of the solar cell 100.

[0088] It is understood that in the revelation the fourth doped layers 110 may be arranged in the second recessed depressions 701 as follows: All parts of the first doped layers 30 may be completely contained in the second recessed depressions 701, or the first doped layers 30 may extend partially out of the second recessed depressions 701 in the thickness direction, which is not specifically limited here.

[0089] In some embodiments, the depth of the second recessed depressions can range from 701.5 nm to 400 nm.

[0090] In this way, a poor stress reinforcement effect caused when the thickness of the fourth doped layers 110 is too small due to an insufficient depth of the second recessed wells 701 can be effectively avoided, or an increase in costs caused when the thickness of the fourth doped layers 110 is too large due to an excessive depth of the second recessed wells 701 can be avoided.

[0091] In particular, the depth of the second recessed depressions may be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or any numerical value between 5 nm and 400 nm, which is not specifically limited herein.

[0092] With reference to the Fig. 14 and Fig. 16 In some embodiments, the solar cell 100 may further comprise second insulating layers 120. The second insulating layers 120 may be stacked between the third doped layers 70 and the fourth doped layers 110 to isolate the third doped layers 70 from the fourth doped layers 110.

[0093] In this way, the fourth doped layers 110 are isolated from the third doped layers 70 by the second insulating layers 120, thus preventing the fourth doped layers from coming into direct contact with the third doped layers. At the same time, a passivation effect of the third doped layers 70 can be ensured.

[0094] Especially in this case, as in Fig. As shown in Figure 14, in some embodiments the second insulating layers 120 can be arranged directly on surfaces of the third doped layers 70 and cover the third doped layers 70, and the fourth doped layers 110 can cover the second insulating layers 120. As shown in Fig. As shown in Figure 16, in some embodiments the second insulating layers 120 can be arranged on the inner walls of the second recessed depressions 701. That is, the inner walls of the second recessed depressions 701 are provided with the second insulating layers 120, and the fourth doped layers 110 can cover the second insulating layers 120 in a stacked manner.

[0095] It is understood that in some embodiments the second insulating layers 120 need not be arranged to isolate the third doped layers 70 from the fourth doped layers 110, which is not specifically limited here.

[0096] In some embodiments, the thickness of the second insulation layer 120 can be greater than 2 nm. This avoids increased process difficulty due to an insufficient thickness of the second insulation layer 120.

[0097] Furthermore, in some embodiments, the second insulating layer 120 may comprise at least one silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer.

[0098] In particular, the second insulation layers 120 in the examples may or may not have a tunneling function and may or may not be an insulating layer, which is not specifically restricted here. A specific film layer can be selected according to the different cell types.

[0099] For example, if the cell is a top-con solar cell or a back-contact cell, the second insulating layer 120 can be at least one silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, and a silicon carbide film layer. The second insulating layer 120 may or may not have a tunneling function.

[0100] If the cell is an HJT solar cell, the second insulating layer 120 can be an intrinsic amorphous silicon layer. It is understood that only a specific selection of the second insulating layers 120 is illustrated here and this cannot be understood as a limitation of the disclosure.

[0101] In some embodiments, the orthogonal projections of the second solder joints 90 onto the third doped layers 70 are located entirely within the second predetermined zones 701. That is, the second solder joints 90 are located entirely above the fourth doped layers 110 in the thickness direction of the solar cell 100.

[0102] In this way, the second solder joints 90 are completely located in the second predetermined zones 701, and the entire lower sections of the second solder joints 90 are all provided with the fourth doped layers 110, so that a soldering tensile force at the second solder joints 90 can be increased to the highest degree and the soldering reliability can be ensured.

[0103] In particular, in the examples, an area of ​​the second predetermined zone 701 may preferably correspond exactly to the area of ​​the orthogonal projections of the second solder joints 90 or be slightly larger than the area of ​​the orthogonal projections of the second solder joints 90.

[0104] In some embodiments, the area of ​​the orthogonal projections of the second solder joints 90 onto the third doped layers 70 can, of course, also be larger than that of the orthogonal projections of the fourth doped layers 110 onto the third doped layers 70 (i.e., the area of ​​the second predetermined zones 701). For example, a single second solder joint 90 can correspond to a plurality of fourth doped layers 110. In this case, the second solder joint 90 can completely cover the fourth doped layers 110. In this case, the ratio of an overlapping area of ​​the fourth doped layers 110 and the second solder joint 90 to a total area of ​​the second solder joint 90 can be greater than 20%, thus avoiding insufficient soldering force.

[0105] In some embodiments, the thickness of the fourth doped layer can range from 110.5 nm to 400 nm.

[0106] In this way, a poor stress amplification effect due to insufficient thickness of the fourth doped layer 110 can be effectively avoided, or increased process difficulty due to insufficient thickness of the fourth doped layer 110 can be avoided. At the same time, cost increases due to excessive thickness of the fourth doped layer 110 can be avoided.

[0107] In particular, the thickness of the fourth doped layers can be 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or any numerical value between 5 nm and 400 nm, which is not specifically limited herein.

[0108] Furthermore, as in Fig. Figure 17 shows that, in a case where the third doped layers 70 are arranged on the first surface 11, the first doped layers 20 comprise several first doped sublayers 21 and several second doped sublayers 22, and the third doped layers 70 comprise several third doped sublayers 71 and several fourth doped sublayers 72. The second doped sublayers 22 each have several first predetermined zones 201, the several first predetermined zones 201 being spaced apart in the second direction, and one number of first solder joints 50 corresponds to one number of first predetermined zones 201. The fourth doped sublayers 72 each have several second predetermined zones 701. The several second predetermined zones 701 being spaced apart in the first direction.A number of pairs of the second solder joints 90 corresponds to a number of the second predetermined zones 701. That is, in this case, the fourth doped layers 110 are arranged on the second predetermined zones 701 of the fourth doped sublayers 72.

[0109] As in Fig. As shown in Figure 17, in the examples in the first direction, the length of the second solder joints 90 can be greater than that of the fourth doped layers 110, and the ratio of the length of the second solder joints 90 over the fourth doped layers 110 to the total length of the second solder joints 90 is greater than or equal to 20%.

[0110] In this way, if the length of the second solder joints 90 in the first direction is large, the ratio of the length (i.e., the length of the overlapping parts between the orthogonal projections of the second solder joints 90 in the thickness direction and the fourth doped layers 110) of the second solder joints 90 over the fourth doped layers 110 to the total length of the second solder joints 90 is set to greater than or equal to 20%, so that a soldering tensile force of the second solder joints 90 can be effectively ensured and an insufficient soldering tensile force can be avoided.

[0111] Preferably, in order to ensure the solder pull force of the second solder joints 90, the ratio of the length of the second solder joints 90 over the fourth doped layers 110 to the total length of the second solder joints 90 is greater than or equal to 50% in the examples.

[0112] In some embodiments, the ratio of the area of ​​orthogonal projections of the fourth doped layers 110 onto the fourth doped sublayers 72 to the area of ​​the fourth doped sublayers 72 is less than 50%. This avoids the situation where large recombination losses occur due to an excessive area ratio of the fourth doped layers 110, because the fourth doped layers 110 readily recombine with the fourth doped sublayers 72.

[0113] In particular, in the examples, the case where “a ratio of an area of ​​orthogonal projections of the fourth doped layers 110 onto the fourth doped sublayers 72 to an area of ​​the fourth doped sublayers 72 is less than 50%” can be a case where a ratio of an area of ​​all fourth doped layers 110 on a single fourth doped sublayer 72 to an area of ​​the single fourth doped sublayer 72 is less than 50%, or a case where a ratio of the sum of areas of all fourth doped layers 110 on the entire back-contact cell to the sum of areas of all fourth doped sublayers 72 is less than 50%, which is not specifically limited here. The first case is preferred.

[0114] As in Fig. As shown in Figure 17, in the examples in the first direction the distance between two adjacent second solder joints is 90.3 mm to 40 mm.

[0115] In this way, the distance between the two adjacent second solder joints 90 is set so that it lies within a rational range, so that the second solder joints 90 can be located essentially within a rational spacing range and, furthermore, an identical fourth doped sublayer 72 can be provided with a sufficient number of second solder joints 90. Thus, hollow soldering during soldering of the solder strip can be avoided and soldering reliability can be ensured.

[0116] In particular, in the examples, the distance between the two adjacent second solder points 90 can be, for example, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm or any numerical value between 3 mm and 40 mm, which is not specifically limited herein.

[0117] In the description, terms such as "an example," "some examples," "case," "specific case," or "some cases" indicate that certain features, structures, materials, or properties described in connection with the examples or cases are present in at least one example or case of the disclosure. The schematic descriptions of the aforementioned terms do not necessarily refer to the same example or case. Furthermore, the described specific features, structures, materials, or properties may be combined appropriately in one or more examples or cases.

[0118] Although the examples of the disclosure are illustrated and described, it can be understood that experts in this field may make various changes, modifications, substitutions and variations to the examples without deviating from the principle and meaning of the disclosure, and the scope of the disclosure is limited by claims and their legal equivalents. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CH 202311238243.4

[0001]

Claims

[1] Solar cell, comprising: a silicon substrate, having a first surface and a second surface opposite each other; first doped layers arranged on the first surface, wherein the first doped layers each have several first predetermined zones; several second doped layers arranged on the first predetermined zones, the second doped layers being spaced apart from each other; a first passivation film layer, arranged on the second doped layers and the first doped layers; and Several first solder joints arranged on the first passivation film layer, wherein orthogonal projections of the first solder joints onto the first doped layers overlap at least partially with orthogonal projections of the second doped layers onto the first doped layers. [2] Solar cell according to claim 1, wherein the polarity of the second doped layers is opposite to that of the first doped layers and the roughness of the surfaces of the second doped layers in contact with the first passivation film layer is greater than that of the surfaces of the first doped layers in contact with the first passivation film layer. [3] Solar cell according to claim 1, wherein the first doped layers are P-type doped layers, the second doped layers are N-type doped layers and the first solder joints are arranged at least partially over the second doped layers. [4] Solar cell according to claim 1, wherein the first predetermined zones are part of surfaces of the first doped layers facing away from the silicon substrate, and the second doped layers are arranged on the first predetermined zones and are all located above the first doped layers; and alternatively, the first predetermined zones are first recessed depressions formed on the first doped layers, the second doped layers are arranged in the first recessed depressions, and the first solder joints at least partially overlap the second doped layers in a thickness direction of the solar cell. [5] Solar cell according to claim 4, wherein, if the first predetermined zones are the first recessed depressions, the depth of the first recessed depressions is 5 nm to 400 nm. [6] Solar cell according to claim 4, further comprising first insulating layers, wherein the first insulating layers are stacked between the first doped layers and the second doped layers to insulate the first doped layers from the second doped layers. [7] Solar cell according to claim 6, wherein the thickness of the first insulation layers is greater than 2 nm. [8] Solar cell according to claim 6, wherein the first insulating layer comprises at least one silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer. [9] Solar cell according to claim 1, wherein an area of ​​orthogonal projections of the first predetermined zones onto the silicon substrate is greater than or equal to that of orthogonal projections of the first solder joints onto the silicon substrate and the orthogonal projections of the first solder joints onto the first doped layers lie completely within the first predetermined zones. [10] Solar cell according to claim 1, wherein the thickness of the second doped layers is 5 nm to 400 nm. [11] Solar cell according to claim 1, wherein the first passivation film layer comprises at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer and a transparent conductive oxide (TCO) film layer. [12] Solar cell according to any one of claims 1 to 11, further comprising third doped layers, a second passivation film layer and several second solder joints, wherein a polarity of the third doped layers is opposite to that of the first doped layers, wherein the first doped layers are arranged on the first surface, the third doped layers are arranged on the second surface, the second passivation film layer is arranged on the third doped layers, and the second solder joints are arranged on the second passivation film layer; and alternatively the first doped layers and the third doped layers are arranged on the first surface, the first passivation film layer is arranged on the first doped layers, the second doped layers and the third doped layers, the second solder joints are further arranged on the first passivation film layer and the second passivation film layer is arranged on the second surface. [13] Solar cell according to claim 12, wherein in a case in which the third doped layers are arranged on the first surface, the multiple first doped layers and the multiple third doped layers are arranged sequentially and alternately in a first direction on the first surface and the first doped layers and the third doped layers all extend in a second direction, the second direction intersecting the first direction. [14] Solar cell according to claim 12, wherein in a case in which the third doped layers are arranged on the first surface, the first doped layers comprise several first doped sublayers and several second doped sublayers and the third doped layers comprise several third doped sublayers and several fourth doped sublayers; the multiple first doped sublayers and the multiple third doped sublayers are arranged sequentially and alternately on the first surface in a first direction and extend in a second direction, the second direction intersecting the first direction; and the multiple second doped sublayers and the multiple fourth doped sublayers are arranged sequentially and alternately on the first surface in the second direction and extend in the first direction, the first doped sublayers are separated from the fourth doped sublayers and are in contact with the second doped sublayers, and the third doped sublayers are separated from the second doped sublayers and are in contact with the fourth doped sublayers, wherein the second doped sublayers each have several first predetermined zones and the several first predetermined zones are arranged at a distance from each other in the second direction. [15] Solar cell according to claim 14, wherein in the first direction the length of the first solder joints is greater than that of the second doped layers and the ratio of the length of the first solder joints over the second doped layers to the total length of the first solder joints is greater than or equal to 20%. [16] Solar cell according to claim 14, wherein in the first direction a ratio of a length of the first solder joints over the second doped layers to a total length of the first solder joints is greater than or equal to 50%. [17] Solar cell according to claim 14, wherein the ratio of an area of ​​orthogonal projections of the second doped layers onto the second doped sublayers to an area of ​​the second doped sublayers is less than or equal to 50%. [18] Solar cell according to claim 14, wherein in the first direction the distance between two adjacent first solder joints is 3 mm to 40 mm. [19] Solar cell according to claim 12, wherein the third doped layers each have several second predetermined zones, the solar cell further comprises fourth doped layers, the fourth doped layers are arranged on the second predetermined zones, the several fourth doped layers are spaced apart from each other and the polarity of the fourth doped layers is opposite to that of the third doped layers; in a case where the third doped layers are arranged on the second surface, the second passivation film layer covers the third doped layers and the fourth doped layers, and orthogonal projections of the second solder joints onto the third doped layers overlap at least partially with orthogonal projections of the fourth doped layers onto the third doped layers; and in a case where the third doped layers are arranged on the first surface, the first passivation film layer covers the first doped layers, the second doped layers, the third doped layers and the fourth doped layers, and the orthogonal projections of the second solder joints onto the third doped layers overlap at least partially with the orthogonal projections of the fourth doped layers onto the third doped layers. [20] Solar cell according to claim 19, wherein the polarity of the fourth doped layers is opposite to that of the third doped layers; in a case where the third doped layers are arranged on the second surface, the roughness of the surfaces of the fourth doped layers in contact with the second passivation film layer is greater than that of the surfaces of the third doped layers in contact with the second passivation film layer; and In a case where the third doped layers are arranged on the first surface, the roughness of the surfaces of the fourth doped layers in contact with the first passivation film layer is greater than that of the surfaces of the third doped layers in contact with the first passivation film layer. [21] Solar cell according to claim 19, wherein the second predetermined zones are part of the surfaces of the third doped layers facing away from the silicon substrate, and the fourth doped layers are arranged on the second predetermined zones and are all located above the third doped layers; and alternatively, the second predetermined zones are second recessed depressions formed on the third doped layers, the fourth doped layers are arranged in the second recessed depressions, and the first solder joints at least partially overlap the second doped layers in the thickness direction of the solar cell. [22] Solar cell according to claim 21, wherein, if the second predetermined zones are the second recessed depressions, the depth of the second recessed depressions is 5 nm to 400 nm. [23] Solar cell according to claim 19, wherein the solar cell further comprises second insulating layers, wherein the second insulating layers are stacked between the third doped layers and the fourth doped layers to insulate the third doped layers from the fourth doped layers. [24] Solar cell according to claim 23, wherein the thickness of the second insulation layers is greater than 2 nm. [25] Solar cell according to claim 23, wherein the second insulating layer comprises at least one of a silicon oxide film layer, a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer and an intrinsic amorphous silicon film layer. [26] Solar cell according to claim 19, wherein the orthogonal projections of the second solder joints onto the third doped layers lie completely within the second predetermined zones. [27] Solar cell according to claim 19, wherein the thickness of the fourth doped layers is 5 nm to 400 nm; and / or the second passivation film layer comprises at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer and a TCO film layer. [28] Solar cell according to claim 19, wherein in a case in which the third doped layers are arranged on the first surface, the first doped layers comprise several first doped sublayers and several second doped sublayers and the third doped layers comprise several third doped sublayers and several fourth doped sublayers; the multiple first doped sublayers and the multiple third doped sublayers are arranged sequentially and alternately on the first surface in a first direction and extend in a second direction, the second direction intersecting the first direction; and the multiple second doped sublayers and the multiple fourth doped sublayers are arranged sequentially and alternately on the first surface in the second direction and extend in the first direction, the first doped sublayers are separated from the fourth doped sublayers and are in contact with the second doped sublayers, and the third doped sublayers are separated from the second doped sublayers and are in contact with the fourth doped sublayers, wherein the second doped sublayers each have several first predetermined zones and the several first predetermined zones are arranged at a distance from each other in the first direction; and the fourth doped sublayers each have several second predetermined zones and the several second predetermined zones are arranged at a distance from each other in the first direction. [29] Cell module comprising several solar cells according to any one of claims 1 to 28. [30] Photovoltaic system comprising the cell module according to claim 29.

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