Back contact solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of back contact solar cells, in particular to a back contact solar cell and a photovoltaic module. The back contact solar cell comprises a silicon substrate, a first doping layer and a second doping layer. The silicon substrate is provided with a backlight surface which is provided with a first area, a second area and a third area. The third region separates the second doped layer from the first doped layer. The second main areas and the first main areas are alternately arranged, and the second auxiliary areas and the first auxiliary areas are alternately arranged in an interdigital mode. The third area comprises a plurality of third main areas and a plurality of third auxiliary areas, the third main areas are arranged between the first main area and the second auxiliary area which are opposite to each other and between the second main area and the first auxiliary area which are opposite to each other, and each third auxiliary area is arranged between the first auxiliary area and the second auxiliary area which are opposite to each other; and the width of the widest part of the third main region is greater than that of the widest part of the third auxiliary region, so that the conversion efficiency and the yield of the back contact solar cell are effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of back-contact solar cells, and particularly to a back-contact solar cell and a photovoltaic module. Background Art

[0002] There are two regions with different conductivity types on the backlight side of the back-contact solar cell, namely a P-type doped region and an N-type doped region. There will inevitably be mutual contact at the junction of the P-type doped region and the N-type doped region to form leakage points, thereby affecting the electrical performance of the back-contact solar cell. Although the P-type doped region and the N-type doped region can be separated by a separating region, if the width of the separating region is not set reasonably, it is difficult to improve the conversion efficiency and yield of the back contact. Summary of the Utility Model

[0003] Embodiments of the present application disclose a back-contact solar cell and a photovoltaic module, which can effectively improve the conversion efficiency and yield of the back-contact solar cell.

[0004] To achieve the above object, in a first aspect, embodiments of the present application disclose a back-contact solar cell, including:

[0005] A silicon substrate having a backlight side, the backlight side having a first region, a second region, and a third region between the first region and the second region;

[0006] A first doping layer disposed on the first region; and

[0007] A second doping layer disposed on the second region, the second doping layer and the first doping layer having opposite conductivity types, and the third region being configured to separate the second doping layer and the first doping layer;

[0008] Wherein, the first region includes an intersecting first main region and a first sub-region, the second region includes an intersecting second main region and a second sub-region, the second main region and the first main region are alternately arranged and parallel to each other, and the second sub-region and the first sub-region are arranged in a finger-crossing and alternating manner; the third region includes a plurality of third main regions and a plurality of third sub-regions, the third main regions are between the opposite first main region and the second sub-region, and between the opposite second main region and the first sub-region, and each of the third sub-regions is between the opposite first sub-region and the second sub-region; the width of the widest part of the third main region is greater than the width of the widest part of the third sub-region.

[0009] In a possible implementation of the first aspect, the third main region is configured to separate the first doping layer on the first main region from the second doping layer on the second sub-region, and to separate the second doping layer on the second main region from the first doping layer on the first sub-region; the third sub-region is configured to separate the first doping layer on the first sub-region from the second doping layer on the second sub-region.

[0010] In a possible implementation of the first aspect, the width D1 of the third main region is 20 μm to 200 μm;

[0011] and / or, the width D2 of the third sub-region is 20 μm to 120 μm;

[0012] and / or, the width of the narrowest part of the third sub-region is D2 min , the width of the third main region is D1, where D2 min / D1 has a value of 0.1 to 1;

[0013] and / or, the width of the widest part of the third sub-region is D2 max , the width of the third main region is D1, where D2 max / D1 has a value of 0.6 to 6.

[0014] In a possible implementation of the first aspect, the first main region is parallel to the length direction or the width direction of the silicon substrate;

[0015] and / or, the number of the first sub-regions is multiple, and the multiple first sub-regions are arranged at intervals along the length direction of the first main region;

[0016] and / or, the included angle between the first main region and the first sub-region is 85° to 95°;

[0017] and / or, the number of the second sub-regions is multiple, and the multiple second sub-regions are arranged at intervals along the length direction of the second main region;

[0018] and / or, the included angle between the second main region and the second sub-region is 85° to 95°.

[0019] In a possible implementation of the first aspect, the ratio of the width of the first main region to the width of the first sub-region is (1 to 4):1;

[0020] and / or, the ratio of the width of the second main region to the width of the second sub-region is (1 to 4):1.

[0021] In a possible implementation of the first aspect, the silicon substrate further has a light-receiving surface, the light-receiving surface is disposed opposite to the backlight surface, and the light-receiving surface is a matte surface structure;

[0022] And / or, the third region is a matte surface structure.

[0023] In a possible implementation of the first aspect, the first doped layer is first doped polysilicon, and a first dielectric layer is further disposed between the first doped polysilicon and the backlight surface;

[0024] The second doped layer is a second doped polysilicon layer, and a second dielectric layer is further disposed between the second doped polysilicon and the backlight surface.

[0025] In a possible implementation of the first aspect, the setting region of the first dielectric layer is consistent with the patterned region of the first region;

[0026] And / or, the thickness of the first dielectric layer is 0.1 nm to 5 nm;

[0027] And / or, the first dielectric layer is a silicon oxide layer;

[0028] And / or, the setting region of the first doped polysilicon is consistent with the patterned region of the first region;

[0029] And / or, the thickness of the first doped polysilicon is 100 nm to 300 nm;

[0030] And / or, the setting region of the second dielectric layer is consistent with the patterned region of the second region;

[0031] And / or, the thickness of the second dielectric layer is 0.1 nm to 5 nm;

[0032] And / or, the second dielectric layer is a silicon oxide layer;

[0033] And / or, the setting region of the second doped polysilicon is consistent with the patterned region of the second region;

[0034] And / or, the thickness of the second doped polysilicon is 100 nm to 300 nm.

[0035] In a possible implementation of the first aspect, the back-contact solar cell further includes:

[0036] A first passivation layer, the silicon substrate further has a light-receiving surface, the light-receiving surface is disposed opposite to the backlight surface, and the first passivation layer is disposed on the light-receiving surface;

[0037] A first antireflection layer, the first antireflection layer is disposed on a side of the first passivation layer facing away from the silicon substrate;

[0038] A second passivation layer, which is disposed on a side of the first doped layer facing away from the silicon substrate, a side of the second doped layer facing away from the silicon substrate, and the third region;

[0039] A second antireflection layer, which is disposed on a side of the second passivation layer facing away from the silicon substrate;

[0040] A first electrode, which sequentially passes through the second antireflection layer and the second passivation layer and then makes an ohmic contact with the first doped layer; and

[0041] A second electrode, which sequentially passes through the second antireflection layer and the second passivation layer and then makes an ohmic contact with the second doped layer.

[0042] In a second aspect, an embodiment of the present application discloses a photovoltaic module, which includes a plurality of serially and / or parallely connected solar cells, and at least one of the solar cells is the back-contact solar cell according to the first aspect.

[0043] Compared with the prior art, the beneficial effect of the present application is that: the back-contact solar cell separates the first doped layer and the second doped layer through the third region, so as to reduce the number of leakage points formed by the mutual contact of the first doped layer and the second doped layer, thereby reducing the leakage phenomenon and effectively improving the conversion efficiency of the back-contact solar cell.

[0044] Further, the width of the widest part of the third main region is greater than the width of the widest part of the third sub-region. The wider third main region reduces the probability of concavities appearing in the first doped layer on the first main region and the second doped layer on the second main region, so as to improve the EL (Electro Luminescence) efficiency and yield of the back-contact solar cell, and can also reduce the probability of residues appearing on the third main region, so as to reduce the number of leakage points. The narrower third sub-region can reduce the area occupied by the third region on the backlight surface, and to a certain extent, can make the areas of the first region and the second region larger. In addition, the patterning process of the third main region is carried out in the opposite direction. Compared with the third main region, the patterning processes between the third sub-regions are carried out in the same direction, and the working error of the same-direction patterning is smaller, so that the abnormal polishing phenomenon caused by laser defects can also be effectively reduced. In other words, the passivation area of the first doped layer and the second doped layer is larger. The widths of the first sub-region and the second sub-region located on both sides of the third sub-region can be wider, and the first doped layer on the first sub-region and the second doped layer on the second sub-region are wider, which is beneficial to paste printing, reduces defects such as broken grids and virtual printing, and effectively improves the conversion efficiency and yield of the back-contact solar cell. Description of the Drawings

[0045] To more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings required for use in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0046] Figure 1 Schematic structural diagram of a back-contact solar cell disclosed in an embodiment of the present application;

[0047] Figure 2 Schematic structural diagram of the backlight side of a silicon substrate disclosed in an embodiment of the present application;

[0048] Figure 3 is Figure 2 Partial enlarged view of area A shown in

[0049] Explanation of reference numerals:

[0050] 100, silicon substrate; 110, backlight side; 111, first region; 1111, first main region; 1112, first sub-region; 112, second region; 1121, second main region; 1122, second sub-region; 113, third region; 1131, third main region; 1132, third sub-region; 120, light-receiving surface; 200, first doping layer; 300, second doping layer; 400, first dielectric layer; 500, second dielectric layer; 600a, first passivation layer; 700a, first antireflection layer; 600b, second passivation layer; 700b, second antireflection layer; 800a, first electrode; 800b, second electrode. Detailed implementation manners

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0052] In the present application, terms such as "upper" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation or be constructed and operated in a specific orientation.

[0053] Moreover, in addition to being used to indicate orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0054] In addition, the terms "arranged" and "provided with" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, components or parts (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, components or parts. Unless otherwise specified, the meaning of "a plurality" is two or more.

[0056] The back-contact solar cell has two doping layers with opposite conduction types, namely the first doping layer and the second doping layer. The set area of the first doping layer is the first area, and the set area of the second doping layer is the second area. In order to reduce the leakage caused by the contact between the two doping layers with opposite conduction types, a third area can be set between the first area and the second area. However, the inventor's research found that although setting the third area can reduce leakage, it also causes other problems, making it impossible to further improve the conversion efficiency and yield of the back-contact solar cell.

[0057] More specifically, the inventor's research found that since the third area is formed by means of laser removal, other methods can also be combined, such as laser removal combined with etching and polishing. When the width of each part of the third area is relatively narrow, abnormal polishing caused by laser defects is likely to occur. Laser defects include, for example, defects such as missing light spots or multiple light spots. Specifically, "missing light spot" means the absence of a laser light spot. It can be understood that the area without a light spot will cause the film layer to be removed not to be removed. Specifically, when the phenomenon of missing light spots occurs, it is finally manifested as non-polishing or polishing residue in the third main area, which in turn leads to leakage.

[0058] Correspondingly, "multiple light spots" means that there are too many laser light spots, and the excess light spot area will cause the film layer to be retained to be removed. When the phenomenon of multiple light spots occurs, the film layer is removed too much, and the first doping layer on the first main area and the second doping layer on the second main area are prone to local concavities relative to the designed pattern. Subsequently, when printing the paste to make electrodes on the first doping layer and the second doping layer, since the paste is printed according to the above-mentioned designed pattern, the paste printed at the concave position will directly contact the silicon substrate, affecting the EL efficiency and yield of the back-contact solar cell.

[0059] When the widths of all parts of the third area are relatively wide, it will cause the areas of the first area and the second area to become smaller, and then cause the passivation areas of the first doping layer and the second doping layer to become smaller, and will also affect the paste printing, resulting in defective phenomena such as broken grids and virtual printing.

[0060] Based on the above analysis, the present application provides a back-contact solar cell, wherein the width of the widest part of the third main area is greater than the width of the widest part of the third sub-area. The relatively wide third main area reduces the probability of concavities in the first doping layer on the first main area and the second doping layer on the second main area, so as to improve the EL (Electro Luminescence) efficiency and yield of the back-contact solar cell, and can also reduce the probability of residues on the third main area, so as to reduce the number of leakage points. The relatively narrow third sub-area can reduce the area occupied by the third area on the backlight surface, and to a certain extent, can make the areas of the first area and the second area larger. In other words, the passivation areas of the first doping layer and the second doping layer are larger. The widths of the first sub-area and the second sub-area located on both sides of the third sub-area can be wider, and the first doping layer on the first sub-area and the second doping layer on the second sub-area are wider, which is beneficial to paste printing, reduces defective phenomena such as broken grids and virtual printing, and effectively improves the conversion efficiency and yield of the back-contact solar cell.

[0061] Next, the technical solutions of the present invention will be described in conjunction with embodiments and drawings.

[0062] In the first aspect, as Figures 1 to 3 shown, an embodiment of the present application discloses a back-contact solar cell, including a silicon substrate 100, a first doping layer 200, and a second doping layer 300. Optionally, the silicon substrate 100 may be an N-type silicon substrate or a P-type silicon substrate. Further, the silicon substrate 100 also has a light-receiving surface 120, and the light-receiving surface 120 is disposed opposite to the backlight surface 110. Preferably, the light-receiving surface 120 is a matte surface structure to enhance the light utilization rate of the light-receiving surface 120.

[0063] The silicon substrate 100 has a backlight surface 110, and the backlight surface 110 has a first region 111, a second region 112, and a third region 113 between the first region 111 and the second region 112.

[0064] The first doping layer 200 is disposed on the first region 111. The second doping layer 300 is disposed on the second region 112. The second doping layer 300 and the first doping layer 200 have opposite conductivity types. For example, the first doping layer 200 is an N-type doping layer and the second doping layer 300 is a P-type doping layer, or the first doping layer 200 is a P-type doping layer and the second doping layer 300 is an N-type doping layer. The third region 113 is configured to separate the second doping layer 300 and the first doping layer 200, so as to reduce the number of leakage potential points formed by the mutual contact of the first doping layer 200 and the second doping layer 300, thereby reducing the leakage phenomenon and effectively improving the conversion efficiency of the back-contact solar cell.

[0065] Wherein, the first region 111 includes an intersecting first main region 1111 and a first sub-region 1112, the second region 112 includes an intersecting second main region 1121 and a second sub-region 1122, the second main region 1121 and the first main region 1111 are alternately arranged and parallel to each other. Figure 2 In, the second main region 1121 and the first main region 1111 are alternately arranged in the Y0 - Y1 direction, and both the second main region 1121 and the first main region 1111 are parallel to the X0 - X1 direction. The second sub-region 1122 and the first sub-region 1112 are alternately arranged in a finger-crossing manner. Figure 2 In, the second sub-region 1122 and the first sub-region 1112 are alternately arranged in a finger-crossing manner along the X0 - X1 direction. The third region 113 includes a plurality of third main regions 1131 and a plurality of third sub-regions 1132. The third main regions 1131 are between the opposite first main region 1111 and the second sub-region 1122, and between the opposite second main region 1121 and the first sub-region 1112. Each of the third sub-regions 1132 is between the opposite first sub-region 1112 and the second sub-region 1122. The width D1 of the widest part of the third main region 1131 max is greater than the width D2 of the widest part of the third sub-region 1132 max . It can be understood that when the widths of the third main regions 1131 are not equal, the width of the third main region 1131 is a numerical range, and the width D1 of the widest part of the third main region 1131 max refers to the upper limit value or the maximum value of the width range of the third main region 1131. When the widths of the third sub-regions 1132 are not equal, the width of the third sub-region 1132 is a numerical range, and the width D2 of the widest part of the third sub-region 1132 max refers to the upper limit value or the maximum value of the width range of the third sub-region 1132.

[0066] The width D1 at the widest part of the third main region 1131 max Relatively wide, which can effectively avoid the above-mentioned polishing anomalies caused by laser defects, thereby reducing the probability of concavities in the first doping layer 200 on the first main region 1111 and the second doping layer 300 on the second main region 1121, so as to improve the EL efficiency and yield of the back-contact solar cell. It can also reduce the probability of residues on the third main region 1131 to reduce the number of leakage points.

[0067] The width D2 at the widest part of the third sub-region 1132 max Relatively narrow, which can reduce the area occupied by the third region 113 on the backlight surface 110. To a certain extent, it can make the areas of the first region 111 and the second region 112 larger. In addition, the patterning process of the third main region 1131 is in the opposite direction. Compared with the third main region 1131, the patterning process between the third sub-regions 1132 is in the same direction, and the processing error in the same direction is smaller, which can effectively reduce the polishing anomalies caused by laser defects. In other words, the passivation areas of the first doping layer 200 and the second doping layer 300 are larger. The widths of the first sub-region 1112 and the second sub-region 1122 on both sides of the third sub-region 1132 can be wider, and the first doping layer 200 on the first sub-region 1112 and the second doping layer 300 on the second sub-region 1122 are wider, which is beneficial to paste printing, reducing defects such as broken grids and virtual printing, and effectively improving the conversion efficiency and yield of the back-contact solar cell.

[0068] Furthermore, in combination with Figure 1 and Figure 2 , the third main region 1131 is configured to separate the first doping layer 200 on the first main region 1111 from the second doping layer 300 on the second sub-region 1122, and to separate the second doping layer 300 on the second main region 1121 from the first doping layer 200 on the first sub-region 1112. It can be understood that the width D1 at the widest part of the third main region 1131 max Relatively wide, which can reduce the probability of concavities in the first doping layer 200 on the first main region 1111 and the second doping layer 300 on the second sub-region 1122, and can also reduce the probability of concavities in the second doping layer 300 on the second main region 1121 and the first doping layer 200 on the first sub-region 1112.

[0069] The third sub-region 1132 is configured to separate the first doping layer 200 on the first sub-region 1112 from the second doping layer 300 on the second sub-region 1122. It can be understood that the width D2 at the widest part of the third sub-region 1132 maxRelatively narrow, the first doping layer 200 on the first sub-region 1112 and the second doping layer 300 on the second sub-region 1122 are wider, which is conducive to paste printing.

[0070] Preferably, referring to Figure 1 , the third region 113 has a matte surface structure. When the third region 113 has a matte surface structure, it can effectively improve the absorption and utilization of the ground and ambient emitted light on the backlight surface 110, and improve the double-sided utilization rate of the back-contact solar cell.

[0071] The width D1 of the third main region 1131 should not be less than 20 μm to avoid ineffective isolation, and the width D1 of the third main region 1131 should not be greater than 200 μm to avoid reducing the areas of the first region 111 and the second region 112, making it difficult to effectively passivate the backlight surface 110. Preferably, the width D1 of the third main region 1131 is 20 μm to 200 μm, including any value within this width range, such as 20 μm, 150 μm, or 200 μm, which can not only form effective isolation but also effectively passivate the backlight surface 110. And the width D1 at the widest part of the third main region 1131 max is 200 μm, which can effectively reduce the abnormal polishing phenomenon caused by laser anomalies.

[0072] The width D2 of the third sub-region 1132 should not be less than 20 μm to avoid ineffective isolation, and the width D2 of the third sub-region 1132 should not be greater than 120 μm to avoid reducing the areas of the first region 111 and the second region 112, making it difficult to effectively passivate the backlight surface 110. Preferably, the width D2 of the third sub-region 1132 is 20 μm to 120 μm, including any value within this width range, such as 20 μm, 70 μm, or 120 μm. And the width D2max at the widest part of the third sub-region 1132 is 120 μm, making the first doping layer 200 on the first sub-region 1112 and the second doping layer 300 on the second sub-region 1122 wide enough, which is conducive to subsequent paste printing.

[0073] Preferably, the width at the narrowest part of the third sub-region 1132 is D2 min , the width of the third main region 1131 is D1, where D2 min / D1 has a value of 0.1 to 1, including any value within this numerical range, such as 0.1, 0.5, or 1.

[0074] Preferably, the width at the widest part of the third sub-region 1132 is D2 max , the width of the third main region 1131 is D1, where D2 max / D1 has a value of 0.6 to 6, including any value within this numerical range, such as 0.6, 3, or 6.

[0075] In some embodiments, referring to Figure 2 , the first main region 1111 is parallel to the length direction or the width direction of the silicon substrate 100. In Figure 2 , the first main region 1111 is parallel to the X0-X1 direction. It can be understood that the above setting method is for a square silicon substrate 100, but the silicon substrate 100 can also be of other shapes.

[0076] Furthermore, the number of the first sub-regions 1112 is multiple, and the multiple first sub-regions 1112 are arranged at intervals along the length direction of the first main region 1111. In Figure 2 , the length direction of the first main region 1111 is the X0-X1 direction. Preferably, the included angle between the first main region 1111 and the first sub-regions 1112 is 85° to 95°, including any point value within this included angle range, such as 85°, 90°, or 95°, so as to maximize the utilization of the area on the backlight surface 110. The first doped layer 200 with the same pattern has a better current transmission effect. The included angle between the first main region 1111 and the first sub-regions 1112 is like the included angle between the X0-X1 direction and the Y0-Y1 direction shown in Figure 2 .

[0077] Furthermore, the number of the second sub-regions 1122 is multiple, and the multiple second sub-regions 1122 are arranged at intervals along the length direction of the second main region 1121. The length direction of the second main region 1121 is the Figure 2 X0-X1 direction shown in Figure 2 . Preferably, the included angle between the second main region 1121 and the second sub-regions 1122 is 85° to 95°, including any point value within this included angle range, such as 85°, 90°, or 95°, so as to maximize the utilization of the area on the backlight surface 110. The second doped layer 300 with the same pattern has a better current transmission effect. The included angle between the second main region 1121 and the second sub-regions 1122 is like the included angle between the X0-X1 direction and the Y0-Y1 direction shown in

[0078] Preferably, the ratio of the width of the first main region 1111 to the width of the first sub-regions 1112 is (1 to 4):1, that is, the width of the first main region 1111 is (1 to 4) times the width of the first sub-regions 1112, so as to achieve.

[0079] Preferably, the ratio of the width of the second main region 1121 to the width of the second sub-regions 1122 is (1 to 4):1, that is, the width of the second main region 1121 is (1 to 4 times) the width of the second sub-regions 1122.

[0080] In some embodiments, referring back to Figure 1, the first doping layer 200 is first doped polysilicon, and a first dielectric layer 400 is further provided between the first doped polysilicon and the backlight surface 110. The second doping layer 300 is a second doped polysilicon layer, and a second dielectric layer 500 is further provided between the second doped polysilicon and the backlight surface 110.

[0081] The first dielectric layer 400 and the second dielectric layer 500 can have the function of pinhole channels, enabling the free movement of carriers. By selectively passing carriers through the first doped polysilicon and the second doped polysilicon, it is beneficial to reduce the recombination loss of carriers. Additionally, the first dielectric layer 400 and the second dielectric layer 500 can respectively serve as diffusion barriers to prevent the dopants of the first doped polysilicon and the second doped polysilicon from diffusing into the silicon substrate 100.

[0082] Furthermore, the setting area of the first dielectric layer 400 is consistent with the patterned area of the first region 111. It can be understood that the setting area of the first dielectric layer 400 has the same area and pattern as the patterned area of the first region 111. To better provide interface passivation for the silicon substrate 100, the thickness of the first dielectric layer 400 is 0.1 nm to 5 nm, including any point value within this thickness range, such as 0.1 nm, 2.5 nm, or 5 nm.

[0083] The material of the first dielectric layer 400 can include various dielectric materials, such as at least one of silicon oxide, magnesium fluoride, amorphous silicon, polysilicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Preferably, the first dielectric layer 400 is a silicon oxide layer because the silicon oxide layer has excellent passivation performance, can minimize the recombination loss on the surface of the silicon substrate 100, and is a film with excellent durability for subsequent high-temperature processes.

[0084] Furthermore, the setting area of the first doped polysilicon is consistent with the patterned area of the first region 111. It can be understood that the setting area of the first doped polysilicon has the same area and pattern as the patterned area of the first region 111. Preferably, the thickness of the first doped polysilicon is 100 nm to 300 nm, including any point value within this thickness range, such as 100 nm, 200 nm, or 300 nm, which can not only form good contact with the subsequent fabrication of the first electrode 800a but also reduce optical parasitic absorption.

[0085] Further, the setting area of the second dielectric layer 500 is consistent with the patterned area of the second region 112. It can be understood that the area and the pattern of the setting area of the second dielectric layer 500 are the same as those of the patterned area of the second region 112. In order to better provide interface passivation for the silicon substrate 100, the thickness of the second dielectric layer 500 is 0.1 nm to 5 nm, including any point value within this thickness range, such as 0.1 nm, 2.5 nm, or 5 nm. The material of the first dielectric layer 400 may include various dielectric materials, such as at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Preferably, the second dielectric layer 500 is a silicon oxide layer. This is because the silicon oxide layer has excellent passivation performance, can minimize the recombination loss on the surface of the silicon substrate 100, and is a film with excellent durability for subsequent high-temperature processes.

[0086] Preferably, the setting area of the second doped polysilicon is consistent with the patterned area of the second region 112. It can be understood that the area and the pattern of the setting area of the second doped polysilicon are the same as those of the patterned area of the second region 112. The thickness of the second doped polysilicon is 100 nm to 300 nm, including any point value within this thickness range, such as 100 nm, 200 nm, or 300 nm, which can not only form good contact with the subsequent fabrication of the second electrode 800b but also reduce optical parasitic absorption.

[0087] In some embodiments, referring back to Figure 1 , the back-contact solar cell further includes a first passivation layer 600a, a first antireflection layer 700a, a second passivation layer 600b, a second antireflection layer 700b, a first electrode 800a, and a second electrode 800b.

[0088] The first passivation layer 600a is disposed on the light-receiving surface 120. The first antireflection layer 700a is disposed on a surface of the first passivation layer 600a facing away from the silicon substrate 100. Optionally, the first passivation layer 600a is an aluminum oxide layer with a thickness of 3 μm to 8 μm, and the first antireflection layer 700a is a silicon nitride layer with a thickness of 60 μm to 90 μm. The first passivation layer 600a is mainly used for passivating the light-receiving surface 120, and the main function of the first antireflection layer 700a is to reduce the loss of reflected light on the light-receiving surface 120.

[0089] The second passivation layer 600b is disposed on a side of the first doped layer 200 facing away from the silicon substrate 100, a side of the second doped layer 300 facing away from the silicon substrate 100, and the third region 113. The second antireflection layer 700b is disposed on a side of the second passivation layer 600b facing away from the silicon substrate 100. Optionally, the second passivation layer 600b is an aluminum oxide layer with a thickness of 3 μm to 8 μm, and the second antireflection layer 700b is a silicon nitride layer with a thickness of 80 μm to 110 μm. The second passivation layer 600b is mainly used for passivating the backlight surface 110, and the main function of the second antireflection layer 700b is to reduce the loss of reflected light from the backlight surface 110.

[0090] The first electrode 800a sequentially passes through the second antireflection layer 700b and the second passivation layer 600b and then makes an ohmic contact with the first doped layer 200. The second electrode 800b sequentially passes through the second antireflection layer 700b and the second passivation layer 600b and then makes an ohmic contact with the second doped layer 300.

[0091] In a second aspect, an embodiment of the present application discloses a photovoltaic module, including a plurality of series-connected and / or parallel-connected solar cells, and at least one solar cell is the back-contact solar cell described in the first aspect.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A back contact solar cell, characterized in that: include: A silicon substrate, wherein the silicon substrate has a backlight surface, and the backlight surface has a first area, a second area, and a third area between the first area and the second area; a first doping layer, wherein the first doping layer is disposed on the first region; as well as a second doped layer, the second doped layer being disposed on the second region, the second doped layer and the first doped layer having opposite conductivity types, and the third region being configured to separate the second doped layer from the first doped layer; Among them, the first area includes an intersecting first main area and a first sub-area, the second area includes an intersecting second main area and a second sub-area, the second main area and the first main area are alternately arranged and parallel to each other, and the second sub-area and the first sub-area are alternately arranged in an interdigitated manner; the third area includes a plurality of third main areas and a plurality of third sub-areas, the third main area is between the relative first main area and the second sub-area, and between the relative second main area and the first sub-area, and each of the third sub-areas is between the relative first sub-area and the second sub-area; the width of the widest part of the third main area is greater than the width of the widest part of the third sub-area.

2. The back contact solar cell according to claim 1, characterized in that: The third main region is configured to separate the first doped layer on the first main region from the second doped layer on the second sub-region, and to separate the second doped layer on the second main region from the first doped layer on the first sub-region; The third sub-region is configured to separate the first doped layer on the first sub-region from the second doped layer on the second sub-region.

3. The back contact solar cell according to claim 1, characterized in that: The width D1 of the third main region is 20 μm to 200 μm; And / or, the width D2 of the third sub-region is 20 μm to 120 μm; And / or, the narrowest width of the third sub-region is D2 min , the width of the third main area is D1, wherein D2 min / D1 value is 0.1~1; And / or, the width of the widest part of the third sub-region is D2 max , the width of the third main area is D1, wherein D2 max The value of / D1 is 0.6~6.

4. The back contact solar cell according to claim 1, characterized in that: The first main region is parallel to the length direction or the width direction of the silicon substrate; And / or, there are multiple first sub-regions, and the multiple first sub-regions are arranged at intervals along the length direction of the first main region; and / or, the angle between the first main area and the first secondary area is 85° to 95°; And / or, there are multiple second sub-regions, and the multiple second sub-regions are arranged at intervals along the length direction of the second main region; And / or, an angle between the second main area and the second sub-area is 85° to 95°.

5. The back contact solar cell according to claim 1, characterized in that: The ratio of the width of the first main region to the width of the first sub-region is (1-4):1; And / or, the ratio of the width of the second main region to the width of the second sub-region is (1-4):

1.

6. The back contact solar cell according to claim 1, characterized in that: The silicon substrate further comprises a light-receiving surface, the light-receiving surface is arranged opposite to the backlight surface, and the light-receiving surface is a velvet structure; And / or, the third area is a suede structure.

7. The back-contact solar cell according to any one of claims 1 to 6, characterized in that: The first doped layer is a first doped polysilicon, and a first dielectric layer is provided between the first doped polysilicon and the backlight surface; The second doped layer is a second doped polysilicon layer, and a second dielectric layer is provided between the second doped polysilicon and the backlight surface.

8. The back contact solar cell according to claim 7, characterized in that: The setting area of ​​the first dielectric layer is consistent with the patterned area of ​​the first area; And / or, the thickness of the first dielectric layer is 0.1 nm to 5 nm; And / or, the first dielectric layer is a silicon oxide layer; and / or, the setting area of ​​the first doped polysilicon is consistent with the patterned area of ​​the first region; And / or, the thickness of the first doped polysilicon is 100 nm to 300 nm; and / or, the setting area of ​​the second dielectric layer is consistent with the patterned area of ​​the second region; And / or, the thickness of the second dielectric layer is 0.1 nm to 5 nm; And / or, the second dielectric layer is a silicon oxide layer; and / or, the setting area of ​​the second doped polysilicon is consistent with the patterned area of ​​the second region; And / or, the thickness of the second doped polysilicon is 100 nm to 300 nm.

9. The back-contact solar cell according to any one of claims 1 to 6, characterized in that: The back contact solar cell also includes: a first passivation layer, the silicon substrate further comprising a light-receiving surface, the light-receiving surface being arranged opposite to the backlight surface, and the first passivation layer being arranged on the light-receiving surface; a first anti-reflection layer, wherein the first anti-reflection layer is disposed on a surface of the first passivation layer facing away from the silicon substrate; a second passivation layer, wherein the second passivation layer is disposed on a side of the first doped layer facing away from the silicon substrate, a side of the second doped layer facing away from the silicon substrate, and the third region; a second anti-reflection layer, wherein the second anti-reflection layer is disposed on a surface of the second passivation layer facing away from the silicon substrate; A first electrode, the first electrode sequentially passes through the second anti-reflection layer and the second passivation layer and then makes ohmic contact with the first doping layer; and A second electrode, wherein the second electrode sequentially passes through the second anti-reflection layer and the second passivation layer and then makes ohmic contact with the second doping layer.

10. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells connected in series and / or in parallel, and at least one of the solar cells is a back-contact solar cell according to any one of claims 1 to 9.

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