Solar cell and photovoltaic module

Abstract

The utility model discloses a solar cell and a photovoltaic assembly. The solar cell may include: a silicon substrate; the first doping layer and the first passivation antireflection layer are arranged on one main surface of the silicon substrate in a stacked mode, and a plurality of thickening areas are arranged on the first passivation antireflection layer at intervals; the first main grid lines are embedded in the thickening areas, and the first main grid lines do not penetrate through the first passivation antireflection layer; the first thin grid lines are perpendicular to and in contact with the first main grid lines, and the first thin grid lines at least penetrate through other anti-reflection areas except the thickening area in the first passivation anti-reflection layer and are in ohmic contact with the first doping layer. According to the solar cell, ohmic contact between the main grid and the doping layer can be avoided, so that the metal-induced recombination rate of the solar cell is effectively reduced, and the risk that the main grid falls off in the use process of the photovoltaic module can be avoided.

Description

Technical Field

[0001] The utility model relates to a solar cell and a photovoltaic module. Background Art

[0002] For a solar cell including fine grids and main grids, its preparation process generally is to print fine grid paste on an antireflection layer first, then print main grid paste, and through a sintering process, make the formed fine grids penetrate the antireflection layer to form an ohmic contact with a doping layer below the antireflection layer. On the one hand, during the sintering process, the main grids may also penetrate the antireflection layer, and there is a possibility of forming an ohmic contact with the doping layer, resulting in a relatively high metal-induced recombination rate; on the other hand, the adhesion between the main grids and the antireflection layer is poor. Once the solar cell is applied to a photovoltaic module, the pulling force of the interconnection strip on the main grids makes the main grids have a risk of falling off, damaging the photovoltaic module and resulting in a relatively low service life of the photovoltaic module. Content of the Utility Model

[0003] In view of this, the utility model provides a solar cell and a photovoltaic module. The solar cell can avoid the formation of an ohmic contact between the main grids and the doping layer, so as to effectively reduce the metal-induced recombination rate of the solar cell, and the adhesion between the main grids and the antireflection layer of the solar cell is relatively good, which can avoid the risk of the main grids falling off during the use of the photovoltaic module, so as to effectively improve the service life of the photovoltaic module.

[0004] To solve the above technical problems, the utility model provides the following technical solutions:

[0005] In a first aspect, the utility model provides a solar cell, including:

[0006] A silicon substrate;

[0007] A first doping layer and a first passivation antireflection layer stacked on a main surface of the silicon substrate, wherein the first passivation antireflection layer is provided with a plurality of thickening regions arranged at intervals;

[0008] A first main grid line embedded in each of the thickening regions, the first main grid line not penetrating the first passivation antireflection layer; and,

[0009] A first fine grid line perpendicular to and in contact with the first main grid line, wherein the first fine grid line penetrates at least other antireflection regions outside the thickening regions in the first passivation antireflection layer and is in ohmic contact with the first doping layer.

[0010] In a second aspect, an embodiment of the utility model provides a photovoltaic module, including: the solar cell provided in the first aspect embodiment of the above or a cell piece cut from the solar cell provided in the first aspect embodiment of the above.

[0011] The technical solution of the first aspect of the above-mentioned utility model has the following advantages or beneficial effects:

[0012] The solar cell provided by the embodiment of the present utility model is designed such that the first main grid line is embedded in the thickened area, enabling the first main grid line to form a tight connection with the first passivation and antireflection layer, firmly fixing the first main grid line on the first passivation and antireflection layer. Due to the design of the thickened area, the first main grid line does not penetrate the first passivation and antireflection layer, avoiding the formation of an ohmic contact between the first main grid line and the doped layer, effectively reducing the metal-induced recombination rate of the solar cell. Moreover, there is a good adhesion between the first main grid line and the thickened area of the solar cell, which can avoid the risk of the main grid falling off during the use of the photovoltaic module, effectively improving the service life of the photovoltaic module. Description of the Drawings

[0013] Figure 1 is a schematic plan view of a solar cell according to an embodiment of the present utility model;

[0014] Figure 2 is corresponding to that in the embodiment of the present utility model Figure 1 the first cross-sectional structure schematic diagram of the partial structure cut along line B-B in the shown plan view structure;

[0015] Figure 3 is corresponding to that in the embodiment of the present utility model Figure 1 the first cross-sectional structure schematic diagram of the partial structure cut along line A-A in the shown plan view structure;

[0016] Figure 4 is corresponding to that in the embodiment of the present utility model Figure 1 the second cross-sectional structure schematic diagram of the partial structure cut along line B-B in the shown plan view structure;

[0017] Figure 5 is corresponding to that in the embodiment of the present utility model Figure 1 the third cross-sectional structure schematic diagram of the partial structure cut along line B-B in the shown plan view structure;

[0018] Figure 6 is corresponding to that in the embodiment of the present utility model Figure 1 the second cross-sectional structure schematic diagram of the partial structure cut along line A-A in the shown plan view structure;

[0019] Figure 7 is a schematic diagram of the main process of the preparation method of the solar cell according to an embodiment of the present utility model;

[0020] Figure 8 is a schematic diagram of the partial structure change of the solar cell corresponding to the preparation method of the solar cell according to an embodiment of the present utility model.

[0021] The reference numerals are as follows:

[0022] 10 - silicon substrate; 21 - first doping layer; 22 - first passivation and antireflection layer; 221 - thickening region; 23 - first main grid line; 24 - first fine grid line; 25 - first tunneling oxide layer; 31 - second doping layer; 32 - second passivation and antireflection layer; 33 - second main grid line; 34 - second fine grid line; 35 - second tunneling oxide layer. Detailed implementation manners

[0023] In the embodiments of the present utility model, the stacked arrangement generally refers to that one structural layer is stacked above or below another structure, and this structure can be in direct contact or indirect contact with the main surface of another structure. Among them, direct contact generally means that this one structure is directly formed, grown or deposited on the upper surface or lower surface of another structure; indirect contact generally means that other functional layers are formed between this one structure and another structure.

[0024] In the embodiments of the present utility model, the upper surface or the front surface of a structure generally refers to the main surface that faces the sunlight or faces upward during the use of the solar cell; the lower surface or the back surface of a structure generally refers to the main surface that faces away from the sunlight or faces downward during the use of the solar cell. Among them, the upper surface and the lower surface or the front surface and the back surface of a structure are opposite to each other.

[0025] In the embodiments of the present utility model, "first", "second", etc. involved are used to distinguish different structures, components or different positions of the same structure, rather than limiting the quantity, order, etc. of the structure, components, etc. For example, the first doping layer and the second doping layer involved in the embodiments of the present utility model are generally used to distinguish two doping layers with different doping elements that are in different positions, have certain differences in thickness, and also have certain differences in function. Another example is that the first main grid line and the second main grid line involved in the embodiments of the present utility model are generally used to distinguish the electrodes that are in different positions (respectively arranged on the two main surfaces of the solar cell) and are used to connect with the welding tape to conduct the current of the solar cell.

[0026] In the prior art, generally, fine grid lines are first laid on a solar cell, and then main grid lines are cross-laid on the basis of the fine grid lines, and sintered through a high-temperature sintering process (the temperature is generally not lower than 850 °C) so that the fine grid lines penetrate the passivation antireflection layer and form a stable ohmic contact with a doped layer (such as an emitter or a surface field). Therefore, high-temperature sintering helps to improve the fill factor of the solar cell. However, during the high-temperature sintering process, the main grid lines also form a relatively deep ohmic contact with the doped layer (such as an emitter or a surface field), resulting in an increase in metal-induced recombination and a decrease in open-circuit voltage, which limits the conversion efficiency of the solar cell.

[0027] In order to solve the above problems existing in the prior art, an embodiment of the present invention provides a novel solar cell and a photovoltaic module.

[0028] Wherein, Figure 1 FIG. shows a partial structural schematic diagram of a main surface of the solar cell provided by an embodiment of the present invention; Figures 2 to 6 FIG. shows a cross-sectional structural schematic diagram of a partial structure of the solar cell provided by an embodiment of the present invention.

[0029] As Figures 1 to 6 shown, the solar cell provided by an embodiment of the present invention may include:

[0030] A silicon substrate 10;

[0031] A first doped layer 21 and a first passivation antireflection layer 22 laminated on a main surface of the silicon substrate 10, wherein multiple thickening regions 221 are arranged at intervals in the first passivation antireflection layer 22;

[0032] A first main grid line 23 embedded in each thickening region 221, and the first main grid line 23 does not penetrate the first passivation antireflection layer 22; and,

[0033] A first fine grid line 24 perpendicular to and in contact with the first main grid line 23, wherein the first fine grid line 24 penetrates other antireflection regions 222 outside the thickening regions 221 in the first passivation antireflection layer 22 and makes an ohmic contact with the first doped layer 21.

[0034] Wherein, as Figure 1 shown, a planar structure of a main surface of the solar cell, the first main grid line 23 and the first fine grid line 24 of the solar cell are perpendicular to each other. Figure 2 、 Figure 4 And Figure 5 are cross-sectional structures of the solar cell obtained by cutting along line B-B in the planar structure shown in Figure 1 shown, and from Figure 2 、 Figure 4 And Figure 5As can be seen, the thickening region 221 is located on the side away from the silicon substrate and is surrounded by the first passivation and antireflection layer 22, that is, the bottom surface and the side surface of the thickening region 221 are both part of the first passivation and antireflection layer 22.

[0035] Among them, the main surface of the first doping layer 21 and the first passivation and antireflection layer 22 arranged in a stacked manner can be the front surface of the solar cell or the back surface of the solar cell. In a preferred embodiment, the main surface of the first doping layer 21 and the first passivation and antireflection layer 22 arranged in a stacked manner can be the front surface of the solar cell.

[0036] Such as Figure 2 , Figure 4 and Figure 5 shown, the first passivation and antireflection layer 22 is composed of the thickening region 221 and other antireflection regions arranged alternately. It should be noted that the part of the thickening region 221 close to the first doping layer 21 is integrally formed with other antireflection regions. Specifically, the formation process of the first passivation and antireflection layer 22 can be: first, a passivation and antireflection layer with basically the same thickness at each position of a single layer or a stack is initially formed on the first doping layer 21, and then additional layers are arranged at intervals on the initially formed passivation and antireflection layer. The region corresponding to the additional layer in the initially formed passivation and antireflection layer and the additional layer together constitute the above-mentioned thickening region 221 (as Figure 2 , Figure 4 and Figure 5 shown). In addition, for other antireflection regions outside the thickening region 221 involved in the embodiments of the present invention, they are other regions in the initially formed passivation and antireflection layer except for the regions corresponding to the additional layers.

[0037] It should be noted that Figure 3 and Figure 6 are two cross-sectional structures of the solar cell obtained by cutting along the line A-A in the planar structure corresponding to Figure 1 shown. As can be seen from Figure 3 and Figure 6 , at the position corresponding to the first fine grid line 24, the thickening region 221 is not penetrated by the first fine grid line 24 either. The first fine grid line 24 only penetrates other antireflection regions outside the thickening region 221 in the first passivation and antireflection layer 22. The structure of first setting the first main grid line 23 and then setting the first fine grid line 24 can enable the first main grid line 23 and the first fine grid line 24 to form an alloyed contact, so that the first main grid line 23 and the first fine grid line 24 form a stable electrical connection and can avoid the first main grid line 23 from contacting the first doping layer 21.

[0038] In addition, the relative relationship among the first fine grid line 24, the first main grid line 23, and the first passivation and antireflection layer 22 of the solar cell can also be that the first main grid line 23 is embedded in each thickening region 221 of the first passivation and antireflection layer 22, and the first main grid line 23 does not penetrate the first passivation and antireflection layer 22; the first fine grid line 24 penetrates the first passivation and antireflection layer 22 (i.e., the first fine grid line 24 penetrates the thickening region 221 and other antireflection regions outside the thickening region 221).

[0039] It can be understood that in the solar cell provided by the embodiment of the present invention, the above-mentioned silicon substrate 10 can be an N-type conductive silicon substrate or a P-type conductive silicon substrate. Preferably, the above-mentioned silicon substrate 10 is an N-type conductive silicon substrate.

[0040] It should be noted that although the drawings provided by the embodiments of the present invention ( Figures 2 to 5 ) only exemplarily show that the surface of the silicon substrate 10 is a planar structure, however, the silicon substrate used in the embodiments of the present invention can also be a single-sided textured structure or a double-textured structure. Among them, for the silicon substrate with a single-sided textured structure, the formed solar cell is also a single-textured structure, and for the silicon substrate with a double-textured structure, the formed solar cell is also a double-textured structure. That is to say, each functional layer of the solar cell, such as the first doping layer 21, the first passivation and antireflection layer 22, the second doping layer 31, and the second passivation and antireflection layer 32, etc., are all formed according to the surface topography of the silicon substrate 10.

[0041] Among them, the first doping layer 21 can be the emitter of the solar cell or the surface field of the solar cell. Specifically, for the silicon substrate 10 being an N-type conductive silicon substrate, the above-mentioned first doping layer 21 can be a P+ emitter or an N+ surface field. For the silicon substrate 10 being a P-type conductive silicon substrate, the above-mentioned first doping layer 21 can be an N+ emitter or a P+ surface field. The thickness range of the first doping layer 21 can be 60 - 200 nm. For example, the first doping layer 21 can be 60 nm, 70 nm, 90 nm, 100 nm, 120 nm, 150 nm, 170 nm, 180 nm, 200 nm, etc.

[0042] Among them, the first passivation and antireflection layer 22 can include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride. In addition, the first passivation and antireflection layer 22 can be a single-layer or a stacked structure. For the single-layer first passivation and antireflection layer 22, it can include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride; for the stacked first passivation and antireflection layer 22, each layer in the stacked structure can include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride.

[0043] The solar cell provided by the embodiment of the present utility model is designed such that the first main grid line 23 is embedded in the thickened region 221, enabling the first main grid line 23 to form a tight connection with the first passivation and antireflection layer 22, firmly fixing the first main grid line 23 on the first passivation and antireflection layer 22. Since the first main grid line 23 does not penetrate the thickened region 221 of the first passivation and antireflection layer 22, it can avoid the formation of an ohmic contact between the first main grid line 23 and the first doping layer 21, effectively reducing the metal-induced recombination rate of the solar cell. Moreover, there is a good adhesion between the first main grid line 23 of the solar cell and the thickened region 221 of the first passivation and antireflection layer 22, which can avoid the risk of the main grid falling off during the use of the photovoltaic module, effectively enhancing the service life of the photovoltaic module.

[0044] Further, as Figure 2 , Figure 4 and Figure 5 shown, the thickness D1 of the thickened region 221 is generally 150 - 350 nm. For example, the thickness D1 of the thickened region 221 can be designed as 150 nm, 160 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 290 nm, 300 nm, 320 nm, 330 nm, 350 nm, etc. Through the design of the thickness of the thickened region 221, it can ensure that the thickened region 221 can firmly fix the first main grid line 23 and avoid the contact between the first main grid line 23 and the first doping layer 21.

[0045] In addition, in the structure of the solar cell provided by the embodiment of the present utility model, as Figure 2 , Figure 4 and Figure 5 shown, the depth H of the first main grid line 23 embedded in the thickened region 221 is greater than the thickening thickness of the thickened region 221 relative to other antireflection regions (as Figure 2 , Figure 4 and Figure 5 shown, the thickness of this other antireflection region is D2) (as Figure 2 , Figure 4 and Figure 5As shown, the increased thickness of the thickened region 221 relative to other antireflection regions is: (D1 - D2), and the depth H of the first main grid line 23 embedded in the thickened region 221 is less than the thickness D1 of the thickened region 221. So that the thickened region 221 can better wrap the first main grid line 23. In addition, by designing the structure: the depth H of the first main grid line 23 embedded in the thickened region 221 is greater than the increased thickness (D1 - D2) of the thickened region 221 relative to other antireflection regions, so that other antireflection regions outside the thickened region 221 in the first passivation antireflection layer 22 play a supporting role on the side walls of the thickened region 221, so that the thickened region 221 can still remain stable after being embedded in the first main grid line 23, enhancing the acting force of the first passivation antireflection layer 22 on the first main grid line 23 and better stabilizing the first main grid line 23. Then, after the first main grid line 23 is connected to the solder strip, even if it is pulled by the solder strip, the first main grid line 23 can still be relatively well fixed on the solar cell.

[0046] Furthermore, on the basis of the thickness D1 of the thickened region 221 designed for the solar cell above, relative to other antireflection regions in the first passivation antireflection layer 22, the increased thickness (i.e., D1 - D2) of the thickened region 221 is generally 30 - 200 nm. For example, the increased thickness of the thickened region 221 relative to other antireflection regions can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 140 nm, 160 nm, 180 nm, 200 nm, etc. In addition, in the first passivation antireflection layer 22, the thickness D2 of other antireflection regions outside the thickened region 221 is generally 50 - 150 nm. For example, the thickness of this other antireflection region can be 50 nm, 60 nm, 65 nm, 70 nm, 80 nm, 85 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 150 nm, etc.

[0047] Generally speaking, there is a certain relationship between the thickness D1 of the thickening region 221, the thickening thickness of the thickening region 221, and the thickness D2 of other antireflection regions outside the thickening region 221. That is, the larger the thickness D2 of other antireflection regions, the larger the range of the thickening thickness that can be selected for the thickening region 221 (that is to say, the larger the thickness D2 of other antireflection regions, under the condition that the thickness of the thickening region 221 is within the range of 150 - 350 nm and the thickening thickness of the thickening region 221 is within the range of 30 - 200 nm, the larger the range of the thickening thickness that can be selected for the thickening region 221), and the smaller the thickness D2 of other antireflection regions, the larger the thickening thickness that needs to be set for this thickening region 221, and the smaller the range of the thickening thickness that can be selected for the thickening region 221 (that is to say, the smaller the thickness D2 of other antireflection regions, under the condition that the thickness of the thickening region 221 is within the range of 150 - 350 nm and the thickening thickness of the thickening region 221 is within the range of 30 - 200 nm, the smaller the range of the thickening thickness that can be selected for the thickening region 221). For example, when the thickness D2 of other antireflection regions is set to 50 nm, the thickening thickness of the thickening region 221 generally needs to be selected within the range of 100 - 200 nm so that the thickness D1 of the thickening region 221 is within the range of 150 - 350 nm; for example, when the thickness D2 of other antireflection regions is 80 nm, the thickening thickness of the thickening region 221 generally needs to be selected within the range of 70 - 200 nm so that the thickness D1 of the thickening region 221 is within the range of 150 - 350 nm; for another example, when the thickness D2 of other antireflection regions is 100 nm, the thickening thickness of the thickening region 221 can generally be arbitrarily selected within the range of 50 - 200 nm; for still another example, when the thickness D2 of other antireflection regions is 150 nm, the thickening thickness of the thickening region 221 can generally be arbitrarily selected within the range of 30 - 200 nm.

[0048] By controlling the thickening thickness of the thickening region 221 relative to other antireflection regions in the first passivation antireflection layer 22, the acting force of the first passivation antireflection layer 22 on the first main grid line 23 can be further enhanced, the first main grid line 23 can be better stabilized, and relative to other antireflection regions in the first passivation antireflection layer 22, the thickening thickness of the thickening region 221 and the thickness D1 of the thickening region 221 cooperate to ensure a stable ohmic contact between the first fine grid line 24 and the first doping layer 21.

[0049] For the formation of the first main grid line 23, the first main grid line 23 of the thickening region 221 is formed by printing main grid paste on the thickening region 221 and sequentially performing sintering treatment and laser enhanced contact treatment on the printed main grid paste. Among them, the structure of the thickening region 221 before the formation of the first main grid line 23 is as Figure 8 shown. That is to say, by Figure 8The main grid paste is printed on the thickened area 221 as shown, and then the main grid paste is sequentially sintered and laser enhanced contact treated to obtain the first main grid line 23. Through the cooperation of the thickened area 221, the main grid paste for printing the first main grid line 23, and sintering, no new processes are added to the production process of the solar cell, enabling the solar cell to achieve mass production and effectively controlling the production process and cost of the solar cell.

[0050] For printing the main grid paste on the thickened area 221, the projection of the main grid paste on the silicon substrate 10 falls within the projection area of the thickened area 221 on the silicon substrate 10. To ensure that the thickened area 221 can form a relatively reliable bond with the first main grid line 23. Additionally, during the process of printing the main grid paste for forming the first main grid line 23 on the thickened area 221, the width of the printed main grid paste is controlled to be smaller than the width of the thickened area 221. That is to say, the projection of the printed main grid paste on the silicon substrate 10 falls within the projection area of the thickened area 221 on the silicon substrate 10, which can also effectively prevent the first main grid line 23 from contacting the first doping layer 21.

[0051] In addition, while the above-mentioned sintering treatment and laser enhanced contact treatment are sequentially performed on the printed main grid paste, the sintering treatment and laser enhanced contact treatment are also synchronously performed on the printed fine grid paste. Specifically, in this laser enhanced contact treatment, by selecting different pastes for the first main grid line 23 and the first fine grid line 24, laser scanning is performed on the main surfaces where the first main grid line 23 and the first fine grid line 24 are located to excite carriers, and after applying a reverse bias voltage to the first main grid line 23 and the first fine grid line 24, a local current of several amperes is generated, and sintering occurs at the corresponding location, triggering the mutual diffusion of the silver paste and silicon, which will significantly reduce the contact resistance between the metal and the semiconductor. And due to the difference in the pastes used for the first main grid line 23 and the first fine grid line 24, the first fine grid line 24 penetrates the first passivation and antireflection layer 22 and contacts the first doping layer 21, while the first main grid line 23 does not contact the first doping layer 21. Among them, the parameters selected for this laser enhanced contact treatment can be adjusted according to the characteristics of the first main grid line 23 and the first fine grid line 24, and are not limited here.

[0052] In order to realize the sintering process cooperation between the above-mentioned thickening region 221 and the first main grid line 23, and realize the synchronous sintering of the first main grid line 23 and the first fine grid line 24 as well as the laser enhanced contact treatment, so as to simplify the production process of the solar cell. In the embodiment of the present invention, slurries with different slurry components and different vitrification temperatures are generally selected for the first main grid line 23 and the first fine grid line 24. More specifically, the first vitrification temperature of the main grid slurry used to form the first main grid line 23 is higher than the second vitrification temperature of the fine grid slurry used to form the first fine grid line 24, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60~170°C. Among them, there are certain differences between the components of the main grid slurry used for the first main grid line 23 and the components of the fine grid slurry used for the first fine grid line 24, such as the content of component silver, the content of aluminum, the content of other components, etc. The existence of this difference causes a temperature difference between the vitrification temperature (i.e., the first vitrification temperature) of the main grid slurry used to form the first main grid line 23 and the vitrification temperature (i.e., the second vitrification temperature) of the fine grid slurry used for the first fine grid line 24. Which specific slurry to choose can be determined according to the vitrification temperature marked on the slurry.

[0053] More specifically, the temperature difference between the first vitrification temperature and the second vitrification temperature being 60~170°C means that the first vitrification temperature is 60~170°C higher than the second vitrification temperature. For example, the temperature difference can be 60°C, 65°C, 68°C, 70°C, 72°C, 75°C, 79°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, etc. For example, if the first vitrification temperature of the main grid slurry used to form the first main grid line 23 is selected as 300°C, then slurries with vitrification temperatures of 130°C, 160°C, 185°C, 190°C, 200°C, 210°C, 230°C, 240°C, etc. can be selected as the fine grid slurries for forming the first fine grid line 24.

[0054] By selecting the temperature difference between the first vitrification temperature and the second vitrification temperature to be 60~170°C, it can be ensured that the first main grid line 23 and the first fine grid line 24 are formed synchronously during sintering, and during the sintering process, the first fine grid line 24 is initially in contact with the first doping layer 21 to form a carrier channel. At the same time, no carrier channel will be formed between the first main grid line 23 and the first doping layer 21. Then, by laser enhanced contact treatment of the sintered first main grid line 23 and the first fine grid line 24, a reliable ohmic contact can be formed between the first fine grid line 24 and the first doping layer 21, while the first main grid line 23 and the first doping layer 21 can still remain isolated.

[0055] Specifically, when the fine grid paste used for the first fine grid line 24 is an aluminum-containing paste, the temperature difference between the first vitrification temperature and the second vitrification temperature is generally 120 - 170 °C. For example, the temperature difference between the first vitrification temperature and the second vitrification temperature can be 120 °C, 130 °C, 133 °C, 135 °C, 140 °C, 145 °C, 150 °C, 160 °C, 165 °C, 170 °C, etc. That is, for the case where the aluminum-containing paste is used as the fine grid paste, by increasing the temperature difference between the first vitrification temperature and the second vitrification temperature, a stable ohmic contact can be formed between the first fine grid line 24 and the first doping layer 21, and at the same time, it can be ensured that the first main grid line 23 is completely isolated from the first doping layer 21.

[0056] When the fine grid paste used for the first fine grid line 24 is an aluminum-free paste, the temperature difference between the first vitrification temperature and the second vitrification temperature is generally 60 - 150 °C. For example, the temperature difference between the first vitrification temperature and the second vitrification temperature can be 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 88 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 120 °C, 126 °C, 130 °C, 135 °C, 138 °C, 140 °C, 145 °C, 150 °C, etc. That is, compared with the aluminum-containing paste, for the case where the aluminum-free paste is used as the fine grid paste, by reducing the temperature difference between the first vitrification temperature and the second vitrification temperature, a stable ohmic contact can be formed between the first fine grid line 24 and the first doping layer 21, and at the same time, it can be ensured that the first main grid line 23 is completely isolated from the first doping layer 21.

[0057] In addition, by coordinating the temperature difference between the first vitrification temperature and the second vitrification temperature with sintering and laser enhanced contact treatment, while effectively reducing the sintering temperature, the fill factor of the solar cell can be improved, the metal-induced recombination rate can be reduced, and the open circuit voltage can be increased, so as to achieve the purpose of improving the photoelectric conversion efficiency of the solar cell.

[0058] In the embodiment of the present invention, based on the composition and glass transition temperature of the fine grid paste of the first fine grid line 24, and in coordination with the temperature difference between the first vitrification temperature and the second vitrification temperature provided in the above embodiment, the main grid paste used for the first main grid line 23 can be selected. Or based on the composition and glass transition temperature of the main grid paste used for the first main grid line 23, and in coordination with the temperature difference between the first vitrification temperature and the second vitrification temperature provided in the above embodiment, the fine grid paste of the first fine grid line 24 can be selected.

[0059] In addition, for the above-mentioned first main grid line 23 and first fine grid line 24, generally, the main grid paste corresponding to the first main grid line 23 is printed in the thickening area 221 first, and then the fine grid paste corresponding to the first fine grid line 24 is printed perpendicular to the main grid paste, so that in the one-step sintering process of the first main grid line 23 and the first fine grid line 24, a stable contact is formed between the first fine grid line 24 and the first main grid line 23.

[0060] Further, based on the solar cell structure provided in any of the above embodiments, as Figures 2 to 6 shown, the solar cell may further include:

[0061] A second doping layer 31 and a second passivation and antireflection layer 32 stacked on another main surface of the silicon substrate 10;

[0062] Second main grid lines 33 spaced apart on the second passivation and antireflection layer 32; and,

[0063] Second fine grid lines 34 perpendicular to and in contact with the second main grid lines 33, penetrating the second passivation and antireflection layer 32, and in ohmic contact with the second doping layer 31.

[0064] Wherein, when the first doping layer 21 is an emitter, the second doping layer 31 is a surface field; when the first doping layer 21 is a surface field, the second doping layer 31 is an emitter.

[0065] Wherein, the second passivation and antireflection layer 32 may include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride. Additionally, the second passivation and antireflection layer 32 may also be a single-layer or multi-layer structure. For the single-layer second passivation and antireflection layer 32, it may include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride; for the multi-layer second passivation and antireflection layer 32, each layer in the multi-layer structure may include at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride.

[0066] The second doping layer 31, the second passivation and antireflection layer 32, the second main grid lines 33, and the second fine grid lines 34 arranged in the above stacking manner can be directly formed by existing technologies as Figure 2 , Figure 3 and Figure 4 shown. Additionally, the second doping layer 31, the second passivation and antireflection layer 32, the second main grid lines 33, and the second fine grid lines 34 arranged in the above stacking manner may also be formed in the same way as the first doping layer 21, the first passivation and antireflection layer 22, the first main grid lines 23, and the first fine grid lines 24 to obtain a structure as Figure 5The structure shown (i.e., thickening regions 221 are formed on the passivation and antireflection layers on the two main surfaces of the solar cell). That is, a plurality of thickening regions 221 are arranged at intervals in the second passivation and antireflection layer 32, the second main grid line 33 is embedded in each thickening region 221, the second main grid line 33 does not penetrate the second passivation and antireflection layer 32, and the second fine grid line 34 penetrates at least other antireflection regions outside the thickening regions 221 in the second passivation and antireflection layer 32 and is in ohmic contact with the second doping layer 31, so as to avoid the formation of ohmic contact between the second main grid line 33 and the second doping layer 31, effectively reduce the metal-induced recombination rate of the solar cell, and there is a good adhesion between the second main grid line 33 and the thickening region 221 of the solar cell, which can avoid the risk of the second main grid line 33 falling off during the use of the photovoltaic module, so as to further effectively improve the service life of the photovoltaic module.

[0067] Among them, whether the first doping layer 21 is used as the surface field or the second doping layer 31 is used as the surface field, the surface field is generally a doped polysilicon layer.

[0068] Among them, the thickness of the surface field can be 60 - 200 nm. For example, the thickness of the surface field can be 60 nm, 70 nm, 75 nm, 86 nm, 90 nm, 95 nm, 100 nm, 120 nm, 130 nm, 150 nm, 170 nm, 190 nm, 200 nm, etc.

[0069] Furthermore, as Figures 4 to 6 shown, the solar cell may further include: a first tunneling oxide layer 25 disposed between the silicon substrate 10 and the first doping layer 21. By providing the first tunneling oxide layer 25, the transmission of majority carriers is facilitated between the first doping layer 21 and the silicon substrate 10, and the transmission of minority carriers is reduced.

[0070] Furthermore, as Figures 2 to 6 shown, the solar cell may further include: a second tunneling oxide layer 35 disposed between the silicon substrate 10 and the second doping layer 31. By providing the second tunneling oxide layer 35, the transmission of majority carriers is facilitated between the second doping layer 31 and the silicon substrate 10, and the transmission of minority carriers is reduced.

[0071] That is to say, for the solar cell provided in the embodiment of the present invention, a first tunneling oxide layer 25 can be provided between the silicon substrate 10 and the first doping layer 21, and a second tunneling oxide layer 35 is not provided between the silicon substrate 10 and the second doping layer 31; it can also be as Figure 2 and Figure 3 shown, a second tunneling oxide layer 35 is provided between the silicon substrate 10 and the second doping layer 31, and a first tunneling oxide layer 25 is not provided between the silicon substrate 10 and the first doping layer 21; it can also be as Figures 4 to 6As shown, a first tunneling oxide layer 25 is provided between the silicon substrate 10 and the first doped layer 21, and a second tunneling oxide layer 35 is provided between the silicon substrate 10 and the second doped layer 31.

[0072] Wherein, the thickness range of the first tunneling oxide layer 25 and the second tunneling oxide layer 35 can be 0.5 - 3 nm. For example, the thickness of the first tunneling oxide layer 25 or the second tunneling oxide layer 35 can be 0.5 nm, 1 nm, 1.5 nm, 1.7 nm, 1.9 nm, 2 nm, 2.2 nm, 2.5 nm, 2.8 nm, 3 nm, etc. The thickness of the first tunneling oxide layer 25 and the thickness of the second tunneling oxide layer 35 can be the same or different, and no limitation is made here.

[0073] Furthermore, an embodiment of the present invention also provides a photovoltaic module. The photovoltaic module may include: the solar cell provided in the above embodiment or the cell piece cut from the solar cell provided in the above embodiment.

[0074] Since the main grid line of the solar cell or the cell piece in the photovoltaic module is located in the thickening area 221, the thickening area 221 can fix the main grid line relatively well. Even if the welding tape pulls the main grid line, the main grid line is not easily detached, ensuring the stable series connection of the cell strings in the photovoltaic module, so as to effectively improve the service life of the photovoltaic module.

[0075] Specifically, for the preparation method of the solar cell provided in the embodiment of the present invention. As Figure 7 shown, the preparation method of the solar cell may include the following steps:

[0076] Step S701: Form a first doped layer 21 on one main surface of the silicon substrate 10;

[0077] Furthermore, for Figures 4 to 6 the structure shown, a tunneling oxide layer formation step may further be included before this step. Specifically, first form a first tunneling oxide layer 25 on one main surface of the silicon substrate 10 by laminating, and then form a first doped layer 21 by laminating on the first tunneling oxide layer 25. The structural changes for forming the first tunneling oxide layer 25 are not shown in the figure.

[0078] In addition, this step may further include: forming a second doped layer 31 on the other main surface of the silicon substrate 10. For the structure for forming the second doped layer 31 as Figure 2 and Figure 3For the structure shown, before forming the second doped layer 31, a second tunneling oxide layer 35 may be formed on another main surface of the silicon substrate. Correspondingly, the second doped layer 31 is formed on the second tunneling oxide layer 35. Among them, based on the fact that the second tunneling oxide layer 35 is formed before the second doped layer 31, the second tunneling oxide layer 35 may be formed before the first doped layer 21. Specifically, the second tunneling oxide layer 35 may be formed synchronously with the first tunneling oxide layer 25. In addition, based on the fact that the second tunneling oxide layer 35 is formed before the second doped layer 31, the second tunneling oxide layer 35 may also be formed after the first doped layer 21. Among them, Figure 8 Exemplarily, the structural change of forming the second tunneling oxide layer 35 before the second doped layer 31 and after the first doped layer 21 is given.

[0079] Step S702: Form a first passivation and antireflection layer 22 on the first doped layer 21, where thickened regions 221 are formed at intervals on the first passivation and antireflection layer 22;

[0080] In addition, based on the fact that the above step S701 forms the second doped layer 31 on another main surface of the silicon substrate 10, in this step S702, it may further include: forming a second passivation and antireflection layer 32 on the second doped layer 31 or forming a second passivation and antireflection layer 32 with thickened regions 221 formed at intervals on the second doped layer 31. Among them, for the structural change of forming the second passivation and antireflection layer 32 on the second doped layer 31 in this step S702, as Figure 8 shown.

[0081] Based on the first passivation and antireflection layer 22 formed in this step S702, the thickening thickness of the thickened region may be 30 - 200 nm. For example, the thickness of the thickened region may be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 140 nm, 160 nm, 180 nm, 200 nm, etc.

[0082] Among them, the formation of the above-mentioned first doped layer 21, second doped layer 31, second tunneling oxide layer 35 and other film layers can adopt existing film layer formation technologies such as physical deposition (such as evaporation coating, sputtering, pulsed laser deposition, etc.), chemical vapor deposition (such as atomic layer deposition, plasma chemical deposition, etc.).

[0083] Specifically, the specific formation method of the first passivation and antireflection layer 22 can be as follows: First, deposit a passivation and antireflection layer with a uniform thickness on the entire main surface of the silicon substrate 20 through any of the above deposition methods. Then, cover a mask on the preliminarily deposited passivation and antireflection layer (the masked area is other areas except the thickening area), and further deposit. Then, remove the mask to obtain the thickening area 221 as described above.

[0084] Step S703: Print the main grid paste in the thickening area 221, and print the fine grid paste perpendicular to the main grid paste;

[0085] Among them, in this step, the projection of the main grid paste printed in the thickening area 221 on the silicon substrate 10 falls within the projection area of the thickening area 221 on the silicon substrate 10.

[0086] In this step, the first vitrification temperature of the main grid paste printed in the thickening area 221 is higher than the second vitrification temperature of the fine grid paste, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60 - 170 °C.

[0087] Based on the second passivation and antireflection layer 32 formed in the above step S702 Figure 8 as shown, this step can also print the main grid paste of the second main grid line and the fine grid paste of the second fine grid line on the other main surface. That is, this step also includes: printing the main grid paste on the second passivation and antireflection layer 32, and printing the fine grid paste perpendicular to the main grid paste; correspondingly, in the subsequent steps, sinter the main grid paste and the fine grid paste on the two main surfaces of the silicon substrate 10 synchronously. In addition, based on the second passivation and antireflection layer 32 with spaced thickening areas 221 formed in the above step S702, print the main grid paste in the thickening area 221 of the second passivation and antireflection layer 32, and print the fine grid paste perpendicular to the main grid paste. Among them, the width of the main grid paste printed in the thickening area 221 of the second passivation and antireflection layer 32 is smaller than the width of the thickening area 221 of the second passivation and antireflection layer 32, and the projection of the main grid paste printed in the thickening area 221 of the second passivation and antireflection layer 32 on the silicon substrate is located within the projection of the thickening area 221 of the second passivation and antireflection layer 32 on the silicon substrate. Further, for the first vitrification temperature of the main grid paste printed in the thickening area 221 of the second passivation and antireflection layer 32 is higher than the second vitrification temperature of the fine grid paste cross-printed with this main grid paste, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60 - 170 °C.

[0088] The printing process used in this step can be directly realized by using the existing grid line printing process in solar cells.

[0089] Step S704: Sinter the main grid paste and the fine grid paste;

[0090] Among them, the sintering temperature can be controlled according to the characteristics of the slurry. Generally speaking, the sintering temperature in this step is between 700 and 850 °C. For example, this step can be carried out at any temperature such as 700 °C, 710 °C, 720 °C, 740 °C, 750 °C, 770 °C, 790 °C, 800 °C, 810 °C, 830 °C, 840 °C, 850 °C, etc., to pre-sinter the main grid slurry and the fine grid slurry, so that the main grid slurry and the fine grid slurry are initially solidified, and the initially solidified fine grid slurry can form an initial contact with the doped layer, and establish a carrier channel between the initially solidified fine grid slurry and the doped layer.

[0091] For the structure of printing the main grid slurry on another main surface of the silicon substrate 10 in the above step S703, this step synchronously sinters the main grid slurry and the fine grid slurry on the two main surfaces of the silicon substrate 10.

[0092] Step S705: Further process the sintered main grid slurry and fine grid slurry located on the first passivation and antireflection layer 22 through a laser enhanced contact technology.

[0093] Through this laser enhanced contact technology, a complete ohmic contact can be formed between the sintered fine grid slurry and the doped layer.

[0094] Among them, this laser enhanced contact technology performs laser scanning on the main surface of the silicon substrate to excite carriers, applies a reverse bias voltage, so that the fine grid line penetrates the passivation and antireflection layer and forms an ohmic contact with the doped layer.

[0095] The solar cell provided by the embodiment of the present invention has a simple structure, and its preparation method can be completed by using the equipment in the existing process, which is simple, highly operable, and suitable for large-scale production.

[0096] Embodiment 1:

[0097] Step A1: Provide an N-type silicon substrate;

[0098] Step B1: Form an N+ emitter on the front surface of the N-type silicon substrate;

[0099] Step C1: Sequentially form a tunneling silicon oxide and an N+ polysilicon layer on the back surface of the N-type silicon substrate;

[0100] Step D1: Form a front passivation and antireflection layer and a back passivation and antireflection layer on the front and back surfaces of the N-type silicon substrate respectively. Among them, a thickening area is provided on the front passivation and antireflection layer;

[0101] Step E1: Print the front main grid metal electrode and the front fine grid metal electrode on the front side of the N-type silicon substrate. Among them, the projection of the front main grid metal electrode on the N-type silicon substrate falls within the projection area of the thickened area on the N-type silicon substrate. Print the back main grid metal electrode and the back fine grid metal electrode on the back side of the N-type silicon substrate, and perform preliminary sintering at a sintering temperature of 700 °C. Then, process the front main grid metal electrode and the front fine grid metal electrode of the battery through the laser enhanced contact optimization technology, so that the front fine grid metal electrode penetrates the front passivation and antireflection layer to make local contact with the second doping type emitter.

[0102] Among them, processing the front main grid metal electrode and the front fine grid metal electrode of the battery through the laser enhanced contact optimization technology includes: laser scanning the front side of the battery silicon wafer to excite carriers, applying a reverse bias voltage, so that the front fine grid metal electrode penetrates the front passivation and antireflection layer to make local contact with the P+ emitter.

[0103] In summary, the embodiments of the present utility model provide the following technical solutions:

[0104] Technical solution 1: A solar cell, comprising:

[0105] A silicon substrate 10;

[0106] A first doping layer 21 and a first passivation and antireflection layer 22 laminated on one main surface of the silicon substrate 10. Among them, the first passivation and antireflection layer 22 is provided with a plurality of thickened areas 221 arranged at intervals;

[0107] A first main grid line 23 embedded in each of the thickened areas 221, and the first main grid line 23 does not penetrate the first passivation and antireflection layer 22; and,

[0108] A first fine grid line 24 perpendicular to and in contact with the first main grid line 23. Among them, the first fine grid line 24 penetrates at least other antireflection areas outside the thickened area 221 in the first passivation and antireflection layer, and makes ohmic contact with the first doping layer 21.

[0109] Technical solution 2: The solar cell according to technical solution 1,

[0110] The depth of the first main grid line 23 embedded in the thickened area 221 is greater than the thickening thickness of the thickened area 221 relative to the other antireflection areas, and the depth of the first main grid line 23 embedded in the thickened area 221 is less than the thickness of the thickened area 221.

[0111] Technical solution 3: The solar cell according to technical solution 1 or 2,

[0112] The thickness of the thickened area 221 is 150 - 350 nm;

[0113] and / or

[0114] The thickness increment of the thickening region 221 is 30 - 200 nm relative to the other antireflection regions.

[0115] Technical solution 4: The solar cell according to technical solution 1 or 2,

[0116] The first vitrification temperature of the main grid paste used to form the first main grid line 23 is higher than the second vitrification temperature of the fine grid paste used to form the first fine grid line 24, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60 - 170 °C.

[0117] Technical solution 5: The solar cell according to technical solution 4,

[0118] The fine grid paste used for the first fine grid line 24 is an aluminum-containing paste, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 120 - 170 °C;

[0119] Or,

[0120] The fine grid paste used for the first fine grid line 24 is an aluminum-free paste, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60 - 150 °C.

[0121] Technical solution 6: The solar cell according to any one of technical solutions 1, 2, and 5,

[0122] The first main grid line 23 is formed by printing the main grid paste on the thickening region 221 and sequentially performing sintering treatment and laser enhanced contact treatment on the printed main grid paste.

[0123] Technical solution 7: The solar cell according to technical solution 6,

[0124] The projection of the main grid paste on the silicon substrate 10 falls within the projection area of the thickening region 221 on the silicon substrate 10.

[0125] Technical solution 8: The solar cell according to technical solution 1, further comprising:

[0126] A second doping layer 31 and a second passivation antireflection layer 32 laminated on the other main surface of the silicon substrate 10;

[0127] Second main grid lines 33 spaced apart on the second passivation antireflection layer 32; and,

[0128] Second fine grid lines 34 that are perpendicular to and in contact with the second main grid lines 33, penetrate the second passivation antireflection layer 32, and are in ohmic contact with the second doping layer 31.

[0129] Technical solution 9. The solar cell according to technical solution 8,

[0130] The first doping layer 21 is the emitter of the solar cell, and the second doping layer 31 is the surface field of the solar cell;

[0131] Or,

[0132] The first doping layer 21 is the surface field of the solar cell, and the second doping layer 31 is the emitter of the solar cell.

[0133] Technical solution 10. The solar cell according to technical solution 8 further includes:

[0134] A first tunneling oxide layer 25 disposed between the silicon substrate 10 and the first doping layer 21;

[0135] And / or,

[0136] A second tunneling oxide layer 35 disposed between the silicon substrate 10 and the second doping layer 31;

[0137] And / or,

[0138] A plurality of thickening regions 221 are arranged at intervals in the second passivation and antireflection layer 32. The second main grid line 33 is embedded in each of the thickening regions 221. The second main grid line 33 does not penetrate the second passivation and antireflection layer 32. The second fine grid line 34 at least penetrates other antireflection regions outside the thickening regions 221 in the second passivation and antireflection layer 32 and is in ohmic contact with the second doping layer 31.

[0139] Technical solution 11. The solar cell according to technical solution 9,

[0140] The surface field is a doped polysilicon layer;

[0141] And / or,

[0142] The thickness of the surface field is 60 - 200 nm.

[0143] Technical solution 12. The solar cell according to technical solution 8,

[0144] The first passivation and antireflection layer 22 includes at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride;

[0145] And / or,

[0146] The second passivation and antireflection layer 32 includes at least one of aluminum oxide, silicon oxide, gallium oxide, silicon nitride, aluminum nitride, silicon oxynitride, and aluminum oxynitride.

[0147] Technical solution 13. A photovoltaic module, comprising: the solar cell according to any one of technical solutions 1 to 12 or the cell slices cut from the solar cell according to any one of technical solutions 1 to 12.

[0148] Technical solution 14. The method for preparing the solar cell according to any one of technical solutions 1 to 12, comprising:

[0149] Step 1. Form a first doped layer 21 on one main surface of the silicon substrate 10;

[0150] Step 2. Form a first passivation and antireflection layer 22 on the first doped layer 21, wherein, thickening regions 221 are formed on the first passivation and antireflection layer 22 at intervals;

[0151] Step 3. Print main grid paste in the thickening regions 221, and print fine grid paste perpendicular to the main grid paste;

[0152] Step 4. Sinter the main grid paste and the fine grid paste;

[0153] Step 5. Further process the sintered main grid paste and fine grid paste located on the first passivation and antireflection layer 22 through laser enhanced contact technology.

[0154] Technical solution 15. The method for preparing the solar cell according to technical solution 14,

[0155] Before step 1, there is also step 1', and the step 1' is to form a first tunneling oxide layer 25 on one main surface of the silicon substrate 10, or / and, to form a second tunneling oxide layer 35 on the other main surface of the silicon substrate 10.

[0156] Technical solution 16. The method for preparing the solar cell according to technical solution 14 or 15,

[0157] Step 1 further includes: forming a second doped layer 31 on the other main surface of the silicon substrate 10;

[0158] Step 2 further includes: forming a second passivation and antireflection layer 32 on the second doped layer 31; or, forming a second passivation and antireflection layer 32 with thickening regions 221 arranged at intervals on the second doped layer 31;

[0159] Step 3 further includes: printing main grid paste on the second passivation and antireflection layer 32, and printing fine grid paste perpendicular to the main grid paste; or, printing main grid paste in the thickening regions 221 of the second passivation and antireflection layer 32, and printing fine grid paste perpendicular to the main grid paste;

[0160] Step 4 includes: synchronously sintering the main grid paste and the fine grid paste on two main surfaces of the silicon substrate 10;

[0161] Among them, the projection of the main grid paste printed in the thickening area 221 on the silicon substrate 10 falls within the projection area of the thickening area 221 on the silicon substrate 10; the first vitrification temperature of the main grid paste printed in the thickening area 221 is higher than the second vitrification temperature of the fine grid paste, and the temperature difference between the first vitrification temperature and the second vitrification temperature is 60 - 170 °C.

[0162] The introduction provided in the above steps is only used to help understand the method, structure and core idea of the present invention. For those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A solar cell, characterized in that, Comprising: A silicon substrate (10); A first doped layer (21) and a first passivation and antireflection layer (22) laminated on one main surface of the silicon substrate (10), wherein a plurality of thickened regions (221) are arranged at intervals in the first passivation and antireflection layer (22); A first main grid line (23) embedded in each of the thickened regions (221), the first main grid line (23) not penetrating the first passivation and antireflection layer (22); and, A first fine grid line (24) perpendicular to and in contact with the first main grid line (23), wherein the first fine grid line (24) penetrates at least other antireflection regions outside the thickened regions (221) in the first passivation and antireflection layer (22) and makes an ohmic contact with the first doped layer (21).

2. The solar cell according to claim 1, characterized in that The depth at which the first main grid line (23) is embedded in the thickened region (221) is greater than the thickening thickness of the thickened region (221) relative to the other antireflection regions, and the depth at which the first main grid line (23) is embedded in the thickened region (221) is less than the thickness of the thickened region (221).

3. The solar cell according to claim 1 or 2, characterized in that The thickness of the thickened region (221) is 150 - 350 nm.

4. The solar cell according to claim 1 or 2, characterized in that Relative to the other antireflection regions, the thickening thickness of the thickened region (221) is 30 - 200 nm.

5. The solar cell according to claim 1, characterized in that, Further comprising: A second doped layer (31) and a second passivation and antireflection layer (32) laminated on the other main surface of the silicon substrate (10); Second main grid lines (33) arranged at intervals on the second passivation and antireflection layer (32); and, Second fine grid lines (34) perpendicular to and in contact with the second main grid lines (33), penetrating the second passivation and antireflection layer (32), and making an ohmic contact with the second doped layer (31).

6. The solar cell according to claim 5, characterized in that, Further comprising: A first tunneling oxide layer (25) provided between the silicon substrate (10) and the first doped layer (21); And / or, A second tunneling oxide layer (35) provided between the silicon substrate (10) and the second doped layer (31).

7. The solar cell according to claim 5 or 6, characterized in that The second passivation and antireflection layer (32) is provided with a plurality of thickened regions (221) arranged at intervals, the second main grid line (33) is embedded in each of the thickened regions (221), the second main grid line (33) does not penetrate the second passivation and antireflection layer (32), the second fine grid line (34) penetrates at least other antireflection regions outside the thickened regions (221) in the second passivation and antireflection layer (32), and makes an ohmic contact with the second doped layer (31).

8. The solar cell according to claim 7, characterized in that The thickness of the thickened region (221) is 150 - 350 nm; Or / and, Relative to the other antireflection regions, the thickening thickness of the thickened region (221) is 30 - 200 nm.

9. A photovoltaic module, characterized in that, Comprising: The solar cell according to any one of claims 1 to 8, or a cell wafer cut from the solar cell according to any one of claims 1 to 8.

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