Solar cell and photovoltaic module

Abstract

A solar cell and a photovoltaic module. The solar cell comprises a silicon substrate, a first transport layer, and a second transport layer; the first transport layer and the second transport layer are arranged on a first surface of the silicon substrate, and the first transport layer and the second transport layer are spaced apart from each other; the first transport layer is provided with an etched region, and a plane where the etched region of the first transport layer is located is lower than or flush with a plane where the first transport layer faces away from the silicon substrate; and / or, the second transport layer is provided with an etched region, and a plane where the etched region of the second transport layer is located is lower than or flush with a plane where the second transport layer faces away from the silicon substrate; and the etched region comprises particles, and the particles can enhance the back reflection of front-side transmitted light, thereby improving the light absorption efficiency of the solar cell.

Description

Solar cell and photovoltaic module TECHNICAL FIELD

[0001] The present application relates to the technical field of solar photovoltaic, in particular to a solar cell and photovoltaic module. BACKGROUND

[0002] The solar cell is a device for directly converting light energy into electrical energy. The light-incident surface of the cell is shielded, which reduces the absorption of sunlight by the cell, and thus the short-circuit current loss of the cell is large. This is a problem faced by almost all silicon-based solar cells at present. Therefore, the research on the solar cell without electrodes on the light-incident surface is particularly important. The back contact cell can solve this problem because the electrodes are arranged on the back surface of the cell, which can minimize the short-circuit current loss caused by the upper surface. In this cell structure, the front surface has no grid lines, and the entire area is used for absorbing sunlight. The back surface of the cell is provided with an electron transport layer and a hole transport layer.

[0003] However, the solar cell of the prior art still has the defects of low back surface reflection efficiency of the front surface transmitted light and poor light absorption efficiency. SUMMARY

[0004] Therefore, the present application provides a solar cell and photovoltaic module, which partially or completely solves the technical problem of low back surface reflection efficiency of the front surface transmitted light and poor light absorption efficiency of the prior art solar cell.

[0005] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0006] In a first aspect, the present application provides a solar cell, which comprises a silicon substrate, a first transport layer and a second transport layer. The first surface of the silicon substrate is provided with the first transport layer and the second transport layer, and the first transport layer and the second transport layer are arranged at intervals. The first transport layer is provided with an etching region, and the plane of the etching region of the first transport layer is lower than or flush with the plane of the first transport layer away from the silicon substrate. And / or, the second transport layer is provided with an etching region, and the plane of the etching region of the second transport layer is lower than or flush with the plane of the second transport layer away from the silicon substrate. The etching region has particulate matter.

[0007] Optionally, in the top view of the solar cell, the maximum length of the particulate matter is less than 50 nm, or less than 20 nm, or less than 15 nm, or the maximum length of the particulate matter ranges from 5 nm to 10 nm.

[0008] Optionally, the etching region has a plurality of particulate matter, and the area coverage of the particulate matter ranges from 0.01% to 60%.

[0009] Optionally, the particulate matter comprises silicon element; or, the particulate matter comprises silicon element and doping element, wherein the type of the doping element comprised in the particulate matter is different from the type of the doping element in the transport layer where the particulate matter is located.

[0010] Optionally, the particulate matter comprises silicon particles in a molten state.

[0011] Optionally, in a top view of the solar cell, the particulate matter is at least one of a circle, an ellipse, and an irregular figure.

[0012] Optionally, the depth range of the particulate matter embedded in the plane of the etching region is 0nm to 50nm.

[0013] Optionally, in the thickness direction of the solar cell, 10% to 100% of the particulate matter is embedded in the plane where the etching region is located.

[0014] Optionally, the etching region is located in the first transport layer, and the area of the etching region accounts for 90% or less of the area of the first transport layer; and / or,

[0015] the etching region is located in the second transport layer, and the area of the etching region accounts for 90% or less of the area of the second transport layer.

[0016] Optionally, the plane where the etching region of the first transport layer is located has a height difference D from the plane of the first transport layer facing away from the silicon substrate, and / or the plane where the etching region of the second transport layer is located has a height difference D from the plane of the second transport layer facing away from the silicon substrate; 0nm≤D≤100nm.

[0017] Optionally, the particulate matter is formed by laser etching.

[0018] Optionally, the first transport layer comprises a first passivation layer and a first doping layer arranged in a stack, the first passivation layer being connected to the first surface and the first doping layer; the second transport layer comprises a second passivation layer and a second doping layer arranged in a stack, the second passivation layer being connected to the first surface and the second doping layer; one of the first doping layer and the second doping layer is an N-type doping layer, and the other of the first doping layer and the second doping layer is a P-type doping layer.

[0019] Optionally, the first transport layer is arranged in a stacked manner with the end portion of the second transport layer close to the end portion of the first transport layer to form a stacked portion; and the solar cell further comprises a transparent conductive layer connected to at least part of the surface of the first transport layer away from the silicon substrate and connected to at least part of the surface of the second transport layer away from the silicon substrate, and the transparent conductive layer has a third opening for breaking the electrical connection between the first transport layer and the second transport layer.

[0020] Optionally, the first transport layer and the second transport layer have an isolation region therebetween; and the solar cell further comprises a transparent conductive layer connected to at least part of the surface of the first transport layer away from the silicon substrate and connected to at least part of the surface of the second transport layer away from the silicon substrate, and the transparent conductive layer has a fourth opening for breaking the electrical connection between the first transport layer and the second transport layer.

[0021] In a second aspect, the embodiments of the present application further provide a photovoltaic module, which comprises a cover plate, a back plate, and a solar cell arranged between the cover plate and the back plate; and the solar cell comprises the solar cell as described above.

[0022] The solar cell disclosed in the present application has the first transport layer provided with an etching region and / or the second transport layer provided with an etching region; the etching region has particulate matter, which can increase the backside reflection of the frontside transmitted light, thereby improving the light absorption efficiency of the solar cell. Moreover, in the case that the first transport layer is provided with the etching region, the plane where the etching region is located is lower than the plane of the first transport layer away from the silicon substrate, which can reduce the parasitic absorption of the first transport layer and improve the light absorption efficiency. Alternatively, the plane where the etching region is located is flush with the plane of the first transport layer away from the silicon substrate, although flush, the presence of the particulate matter in the etching region can reduce the light transmission path compared with the region without the particulate matter, which can reduce the parasitic absorption of the first transport layer and improve the light absorption efficiency. In addition, in the case that the second transport layer is provided with the etching region, the plane where the etching region is located is lower than the plane of the second transport layer away from the silicon substrate, which can reduce the parasitic absorption of the second transport layer and improve the light absorption efficiency. Alternatively, the plane where the etching region is located is flush with the plane of the second transport layer away from the silicon substrate, although flush, the presence of the particulate matter in the etching region can reduce the light transmission path compared with the region without the particulate matter, which can reduce the parasitic absorption of the second transport layer and improve the light absorption efficiency. Therefore, the solar cell of the embodiments of the present application has the advantage of high light absorption efficiency.

[0023] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application more clearly understood and implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment description.

[0025] FIGS. 1 to 7 show cross-sectional structure schematic diagrams of a solar cell in different preparation steps in the embodiments of the present application;

[0026] FIG. 8 is a test image of the section shown in FIG. 3;

[0027] FIG. 9 is a test image of the section shown in FIG. 4;

[0028] FIG. 10 is a test image of the solar cell after plating a transparent conductive layer;

[0029] FIG. 11 is a cross-sectional structure schematic diagram of a solar cell in an embodiment of the present application;

[0030] FIG. 12 is a structure schematic diagram of a solar cell in an embodiment of the present application, in which particles are embedded in an etching region;

[0031] FIG. 13 is a structure schematic diagram of particles of a solar cell in an embodiment of the present application;

[0032] FIG. 14 is a structure schematic diagram of particles of a solar cell in an embodiment of the present application.

[0033] Legend: 10-silicon substrate; 11-first surface; 12-second surface; 20-first transport layer; 21-first passivation layer; 22-first doped layer; 23-etching region; 231-plane where the etching region is located; 30-second transport layer; 31-second passivation layer; 32-second doped layer; 40-transparent conductive layer; 41-particle; 50-laminated part; 51-first opening; 52-second opening; 53-third opening; 61-first electrode; 62-second electrode; 70-third passivation layer; 80-anti-reflection layer. DETAILED DESCRIPTION

[0034] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present application are illustrated, it is to be understood that the application is not limited to the embodiments described herein, but is capable of further realization in various forms. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0035] Referring to FIGS. 1-14, which show schematic diagrams of a solar cell at different manufacturing steps according to embodiments of the present application, the solar cell includes a silicon substrate 10, a first transport layer 20, and a second transport layer 30. The first surface 11 of the silicon substrate 10 is provided with the first transport layer 20 and the second transport layer 30, and the first transport layer and the second transport layer are spaced apart. The first transport layer 20 is provided with an etching region 23, and the plane 231 of the etching region of the first transport layer 20 is lower than or flush with the plane of the first transport layer 20 away from the silicon substrate 10. Alternatively, or in addition, the second transport layer 30 is provided with an etching region 23, and the plane 231 of the etching region is lower than or flush with the plane of the second transport layer 30 away from the silicon substrate 10. The etching region 23 has particulate matter 41 thereon.

[0036] Specifically, in the solar cell, the silicon substrate 10 has a first surface 11 and a second surface 12, and the first surface 11 and the second surface 12 are oppositely distributed, i.e., one of the first surface 11 and the second surface 12 is the front surface of the silicon substrate 10, and the other of the first surface 11 and the second surface 12 is the back surface of the silicon substrate 10.

[0037] Referring to FIGS. 1-7 and 11, the first surface 11 of the silicon substrate 10 is respectively provided with the first transport layer 20 and the second transport layer 30, and the first transport layer and the second transport layer are spaced apart. The spacing is one of: in the plane extension direction of the silicon substrate 10, i.e., in the first direction A, the first transport layer 20 and the second transport layer 30 are alternately spaced apart on the plane of the silicon substrate 10, and the two are in contact or not in contact in the plane extension direction of the silicon substrate 10. The other is that in the plane extension direction of the silicon substrate 10, i.e., in the first direction A, the first transport layer 20 and the second transport layer 30 are alternately spaced apart on the plane of the silicon substrate 10, and the two partially overlap in the thickness extension direction of the silicon substrate 10. The first transport layer 20 and the second transport layer 30 are different in type, and one of the first transport layer 20 and the second transport layer 30 is an electron transport layer, and the other of the first transport layer 20 and the second transport layer 30 is a hole transport layer.

[0038] In the embodiment of the present application, the first transmission layer 20 is provided with an etching region 23, and / or the second transmission layer 30 is provided with an etching region 23; the etching region 23 has a particulate matter 41, which can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell. Moreover, in the case that the first transmission layer 20 is provided with the etching region 23, the plane 231 where the etching region is located is lower than the plane of the first transmission layer 20 away from the silicon substrate 10, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. Alternatively, the plane 231 where the etching region is located is flush with the plane of the first transmission layer 20 away from the silicon substrate 10, although flush, the presence of the particulate matter 41 in the etching region 23 can reduce the light transmission path compared with the region without the particulate matter 41, which can reduce the parasitic absorption of the first transmission layer 20 and improve the light absorption efficiency. In the case that the second transmission layer 30 is provided with the etching region 23, the plane 231 where the etching region is located is lower than the plane of the second transmission layer 30 away from the silicon substrate 10, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. Alternatively, the plane 231 where the etching region is located is flush with the plane of the second transmission layer 30 away from the silicon substrate 10, although flush, the presence of the particulate matter 41 in the etching region 23 can reduce the light transmission path compared with the region without the particulate matter 41, which can reduce the parasitic absorption of the second transmission layer 30 and improve the light absorption efficiency. Therefore, the solar cell of the embodiment of the present application has the advantage of high light absorption efficiency.

[0039] Referring to FIG. 7, in the embodiment of the present application, the thickness direction is the second direction Z, that is, the thickness of the transparent conductive layer 40 (as shown in FIGS. 5, 6 and 11), the thickness of the solar cell, the thickness of the silicon oxide layer, etc. are all in the second direction Z.

[0040] Optionally, the particulate matter 41 is formed by laser etching.

[0041] In the embodiment of the present application, the wavelength and energy of the laser are not specifically limited, for example, a green laser with a wavelength of 532 nm and an energy of 53 μJ is used. For example, the wavelength of the laser is 355 nm.

[0042] Optionally, in the top view of the solar cell, the maximum length of the particulate matter 41 is less than 50 nm; preferably, the maximum length of the particulate matter 41 is less than 20 nm; further preferably, the maximum length of the particulate matter 41 is less than 15 nm; further preferably, the maximum length of the particulate matter 41 ranges from 5 nm to 10 nm. When the size of the particulate matter 41 is in the above range, the particulate matter 41 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency.

[0043] Further, the maximum length of the particulate 41 is less than 50 nm, and the light refraction effect is good. Further, the maximum length of the particulate 41 is less than 20 nm, and the light refraction effect is good, and the contact resistance effect is better than that of the maximum length of the particulate 41 being less than 50 nm. Further, the maximum length of the particulate 41 is in the range of 5 nm to 10 nm, and the light refraction effect and the contact resistance effect are optimal.

[0044] Further, in the top view of the solar cell, the maximum length of the particulate 41 is not limited in the embodiments of the present application, for example, the maximum length of the particulate 41 is 5 nm, 5.5 nm, 6 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0045] Optionally, as shown in FIG. 10, the etching region 23 has a plurality of particulates 41, and the area coverage of the particulate 41 is in the range of 0.01% to 60%. This ensures that the particulate 41 can increase the back reflection of the front transmitted light, thereby improving the light absorption efficiency of the solar cell.

[0046] Optionally, the particulate 41 includes a silicon element; or the particulate 41 includes a silicon element and a doping element. The type of the doping element included in the particulate 41 is different from the type of the doping element in the transmission layer where the particulate 41 is located.

[0047] In the embodiments of the present application, the laser etching forms the particulate 41, and the particulate 41 includes a silicon element. Alternatively, the particulate 41 includes a silicon element and a doping element, and the doping element is at least one of a group III element or at least one of a group V element. For example, the group III element includes boron, aluminum, gallium, indium, etc., and the group V element includes nitrogen, phosphorus, arsenic, antimony, etc.

[0048] For example, the doping element included in the particulate 41 is boron, and the doping element in the first transmission layer where the particulate 41 is located is phosphorus. Alternatively, the doping element included in the particulate 41 is phosphorus, and the doping element in the second transmission layer where the particulate 41 is located is boron.

[0049] Optionally, the particulate 41 includes a molten silicon particle.

[0050] In the embodiments of the present application, the laser etching forms the particulate 41, and the particulate 41 includes a molten silicon particle, and the silicon particle includes a silicon element; alternatively, the silicon particle includes a silicon element and a doping element.

[0051] Optionally, the granular matter 41 is at least one of a circle, an ellipse, and an irregular figure in a top view of the solar cell.

[0052] Further referring to FIG. 13, a structure diagram is shown in which the granular matter 41 is a circle. Referring to FIG. 14, a structure diagram is shown in which the granular matter 41 is an ellipse.

[0053] Optionally, the granular matter 41 is embedded in the plane 231 of the etching region with a depth ranging from 0 nm to 50 nm.

[0054] In the embodiments of the present application, the depth of the granular matter 41 embedded in the plane 231 of the etching region is set according to the use requirement, for example, the depth of the granular matter 41 embedded in the plane 231 of the etching region is 0 nm, 5 nm, 10 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 48 nm, or 50 nm.

[0055] Optionally, referring to FIG. 12, in the thickness direction of the solar cell, 10% to 100% of the granular matter 41 is embedded in the plane 231 of the etching region.

[0056] Further referring to FIG. 12, in the top-to-bottom direction, in the first diagram, 10% of the granular matter 41 is embedded in the plane 231 of the etching region; in the second diagram, 25% of the granular matter 41 is embedded in the plane 231 of the etching region; in the third diagram, 50% of the granular matter 41 is embedded in the plane 231 of the etching region; in the fourth diagram, 75% of the granular matter 41 is embedded in the plane 231 of the etching region; in the fifth diagram, 100% of the granular matter 41 is embedded in the plane 231 of the etching region; and in the sixth diagram, all of the granular matter 41 is embedded in the plane 231 of the etching region.

[0057] Optionally, referring to FIGS. 1 to 7, the etching region 23 is arranged in the first transport layer 20, and the area of the etching region 23 accounts for 90% or less of the area of the first transport layer 20. At this time, the etching region 23 can increase the backside reflection of the frontside transmitted light, thereby improving the light absorption efficiency of the solar cell.

[0058] Optionally, the end portion of the first transport layer 20 close to the second transport layer 30 is arranged in a laminated manner with the end portion of the second transport layer 30 close to the first transport layer 20, and the end portion of the first transport layer 20 is located between the end portion of the second transport layer 30 close to the first transport layer 20 and the first surface 11; and the first transport layer 20 is provided with the etching region 23 except for the end portion of the first transport layer 20. In the above structure of the solar cell according to the embodiment of the application, the etching region 23 has a large area, thereby effectively improving the light absorption efficiency. Moreover, the etching region 23 can be formed by using laser etching in the etching process of the solar cell, thereby saving the process steps.

[0059] Optionally, as shown in FIG. 4, the plane 231 where the etching region of the first transport layer 20 is located has a height difference D with the plane where the first transport layer 20 is away from the silicon substrate 10, and / or the plane where the etching region of the second transport layer 30 is located has a height difference D with the plane where the second transport layer 30 is away from the silicon substrate 10; 0nm≤D≤100nm.

[0060] In actual application, the height difference D of the etching region 23 with the first transport layer 20 and / or the second transport layer 30 can be selected according to the use requirement, for example, D is 0nm, 1nm, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm.

[0061] Optionally, as shown in FIG. 1, the first transport layer 20 comprises the first passivation layer 21 and the first doped layer 22 arranged in a laminated manner, and the first passivation layer 21 is connected to the first doped layer 22 and the first surface 11. Further referring to FIG. 3, the second transport layer 30 comprises the second passivation layer 31 and the second doped layer 32 arranged in a laminated manner, and the second passivation layer 31 is connected to the second doped layer 32 and the first surface 11; one of the first doped layer 22 and the second doped layer 32 is an N-type doped layer, and the other of the first doped layer 22 and the second doped layer 32 is a P-type doped layer. The first transport layer 20 or the second transport layer 30 provided with the N-type doped layer is an electron transport layer, and the first transport layer 20 or the second transport layer 30 provided with the P-type doped layer is a hole transport layer.

[0062] Optionally, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise one or more of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon. That is, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise doped microcrystalline silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise doped amorphous silicon. Alternatively, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise two or three of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon.

[0063] Optionally, the material of the first passivation layer 21 and the material of the second passivation layer 31 both comprise silicon oxide, and the material of the first doped layer 22 and the material of the second doped layer 32 both comprise doped polycrystalline silicon.

[0064] Optionally, the material of the first passivation layer 21 comprises intrinsic amorphous silicon, and the material of the first doped layer 22 comprises one or more of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon; and the material of the second passivation layer 31 comprises silicon oxide, and the material of the second doped layer 32 comprises doped polycrystalline silicon. That is, the material of the first passivation layer 21 comprises intrinsic amorphous silicon, and the material of the first doped layer 22 comprises doped polycrystalline silicon; the material of the second passivation layer 31 comprises silicon oxide, and the material of the second doped layer 32 comprises doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 comprises intrinsic amorphous silicon, and the material of the first doped layer 22 comprises doped microcrystalline silicon; the material of the second passivation layer 31 comprises silicon oxide, and the material of the second doped layer 32 comprises doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 comprises intrinsic amorphous silicon, and the material of the first doped layer 22 comprises doped amorphous silicon; the material of the second passivation layer 31 comprises silicon oxide, and the material of the second doped layer 32 comprises doped polycrystalline silicon. Alternatively, the material of the first passivation layer 21 comprises intrinsic amorphous silicon, and the material of the first doped layer 22 comprises two or three of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon; the material of the second passivation layer 31 comprises silicon oxide, and the material of the second doped layer 32 comprises doped polycrystalline silicon.

[0065] Optionally, the material of the first passivation layer 21 comprises silicon oxide, the material of the first doped layer 22 comprises doped polysilicon; and the material of the second passivation layer 31 comprises intrinsic amorphous silicon, the material of the second doped layer 32 comprises one of doped polysilicon, doped microcrystalline silicon and doped amorphous silicon. That is, the material of the first passivation layer 21 comprises silicon oxide, the material of the first doped layer 22 comprises doped polysilicon; the material of the second passivation layer 31 comprises intrinsic amorphous silicon, the material of the second doped layer 32 comprises doped polysilicon. Alternatively, the material of the first passivation layer 21 comprises silicon oxide, the material of the first doped layer 22 comprises doped polysilicon; the material of the second passivation layer 31 comprises intrinsic amorphous silicon, the material of the second doped layer 32 comprises doped microcrystalline silicon. Alternatively, the material of the first passivation layer 21 comprises silicon oxide, the material of the first doped layer 22 comprises doped polysilicon; the material of the second passivation layer 31 comprises intrinsic amorphous silicon, the material of the second doped layer 32 comprises doped amorphous silicon. Alternatively, the material of the first passivation layer 21 comprises silicon oxide, the material of the first doped layer 22 comprises doped polysilicon; the material of the second passivation layer 31 comprises intrinsic amorphous silicon, the material of the second doped layer 32 comprises two or three of doped polysilicon, doped microcrystalline silicon and doped amorphous silicon.

[0066] Optionally, referring to FIGS. 1-7, the end portion of the first transport layer 20 is laminated with the end portion of the second transport layer 30 close to the end portion of the first transport layer 20 to form a laminated portion 50; referring to FIGS. 5 and 6, the solar cell further comprises a transparent conductive layer 40 connected to at least part of the surface of the first transport layer 20 away from the silicon substrate 10 and connected to at least part of the surface of the second transport layer 30 away from the silicon substrate 10, and the transparent conductive layer 40 has a third opening for breaking the electrical connection between the first transport layer 20 and the second transport layer 30.

[0067] The third opening 53 makes the N region and the P region not connected, and can be used for insulation of the N region and the P region, and has the advantages of good insulation reliability and insulation effect.

[0068] Optionally, referring to FIGS. 1-7, the first transport layer 20 and the second transport layer 30 have an isolation region therebetween; the solar cell further comprises a transparent conductive layer 40 connected to at least part of the surface of the first transport layer 20 away from the silicon substrate 10 and connected to at least part of the surface of the second transport layer 30 away from the silicon substrate 10, and the transparent conductive layer 40 has a fourth opening for breaking the electrical connection between the first transport layer 20 and the second transport layer 30. In the above structure of the present application, the fourth opening also makes the N region and the P region insulated, and has the advantages of good insulation reliability and insulation effect.

[0069] Optionally, referring to FIG. 7, the solar cell further comprises a first electrode 61 and a second electrode 62, the transparent conductive layer 40 is provided with the first electrode 61 at the first transport layer 20 and away from the surface of the silicon substrate 10, and the transparent conductive layer 40 is provided with the second electrode 62 at the second transport layer 30 and away from the surface of the silicon substrate 10.

[0070] Further, the first electrode 61 and the second electrode 62 are provided with a third opening 53, and the first electrode 61 and the second electrode 62 are insulated through the third opening 53. The first electrode 61 and the second electrode 62 are arranged parallel to the extension direction of the laminated part 50 and have a spacing.

[0071] Optionally, referring to FIG. 1 and FIG. 3, the solar cell further comprises an anti-reflection layer 80 and a third passivation layer 70, and the anti-reflection layer 80 and the third passivation layer 70 are sequentially laminated on the second surface 12 of the solar cell.

[0072] The application further provides a photovoltaic module, which comprises a cover plate, a back plate, and a solar cell arranged between the cover plate and the back plate; the solar cell comprises the solar cell as described above.

[0073] The application does not make specific limitation on whether the photovoltaic module further comprises other structures. For example, the photovoltaic module can further comprise a first encapsulation adhesive film arranged between the cover plate and the solar cell, and a second encapsulation adhesive film arranged between the back plate and the solar cell.

[0074] In the solar cell of the photovoltaic module, in the case that the first transport layer 20 is provided with the etching region 23, the plane 231 where the etching region is located is lower than the plane of the first transport layer 20 away from the silicon substrate 10, which can reduce the parasitic absorption of the first transport layer 20 and improve the light absorption efficiency. Alternatively, the plane 231 where the etching region is located is flush with the plane of the first transport layer 20 away from the silicon substrate 10, although flush, the etching region 23 has the particles 41, compared with the region without the particles 41, the light transmission path of the region with the particles 41 is reduced, which can reduce the parasitic absorption of the first transport layer 20 and improve the light absorption efficiency. In the case that the second transport layer 30 is provided with the etching region 23, the plane 231 where the etching region is located is lower than the plane of the second transport layer 30 away from the silicon substrate 10, which can reduce the parasitic absorption of the second transport layer 30 and improve the light absorption efficiency. Alternatively, the plane 231 where the etching region is located is flush with the plane of the second transport layer 30 away from the silicon substrate 10, although flush, the etching region 23 has the particles 41, compared with the region without the particles 41, the light transmission path of the region with the particles 41 is reduced, which can reduce the parasitic absorption of the second transport layer 30 and improve the light absorption efficiency. The photovoltaic module of the application has the advantage of high conversion efficiency.

[0075] The application will be described in further detail below with reference to specific embodiments.

[0076] Embodiment one

[0077] The preparation process of the solar cell comprises the following steps:

[0078] Step 101, as shown in FIG. 1, a first transport layer 20 is formed on a first surface 11 of a silicon substrate 10.

[0079] In this step, the first transport layer 20 is a first passivation layer 21 and a first doped layer 22 arranged in a stack, the first passivation layer 21 is connected to the first surface 11 and the first doped layer 22. Specifically, a low pressure chemical vapor deposition (LPCVD) equipment can be used to sequentially deposit the first passivation layer 21 and the first doped layer 22 on the first surface 11. The silicon substrate 10 is an N-type silicon substrate, the first passivation layer 21 comprises a silicon oxide layer, and the thickness of the silicon oxide layer ranges from 0.5 nm to 5 nm. The first doped layer 22 is an N-type polysilicon layer, and the thickness of the N-type polysilicon layer ranges from 30 nm to 200 nm.

[0080] Step 102, as shown in FIG. 2, etching the first transport layer 20 to form a first opening 51.

[0081] In this step, photolithography or mask etching can be used for patterning treatment to remove the removal area of the first transport layer 20 to form the first opening 51, specifically, the first passivation layer 21 and the first doped layer 22 are removed to form the first opening 51. The width of the first opening 51 ranges from 100 μm to 800 μm.

[0082] Step 103, as shown in FIG. 3, a second transport layer 30 is deposited on the first surface 11 of the silicon substrate 10, and a third passivation layer 70 and an anti-reflection layer 80 are deposited on a second surface 12 of the silicon substrate 10.

[0083] The second transport layer 30 comprises a second passivation layer 31 and a second doped layer 32, the second passivation layer 31 is connected between the second doped layer 32 and the first surface 11. A chemical vapor deposition (CVD) equipment can be used to sequentially deposit the second passivation layer 31 and the second doped layer 32. The second passivation layer 31 is an intrinsic passivation layer, and the thickness of the second passivation layer 31 ranges from 3 nm to 10 nm. The second doped layer 32 is a p-type amorphous silicon layer, and the thickness of the second doped layer 32 ranges from 5 nm to 20 nm.

[0084] A third passivation layer 70 is deposited on the second surface 12 of the silicon substrate 10 using a CVD apparatus. The third passivation layer 70 is an intrinsic passivation layer or a silicon oxide layer. The thickness of the third passivation layer 70 is in the range of 2 nm to 20 nm. A reduction layer 80 is deposited on the third passivation layer 70. The thickness of the reduction layer 80 is in the range of 50 nm to 200 nm.

[0085] Further, as shown in FIG. 8, a test diagram of the first passivation layer 21, the first doped layer 22, the second passivation layer 31, and the second doped layer 32 is shown. The total thickness of the first passivation layer 21, the first doped layer 22, the second passivation layer 31, and the second doped layer 32 is 137 nm.

[0086] At step 104, as shown in FIG. 4, a portion of the second passivation layer 31, a portion of the second doped layer 32, and a portion of the first doped layer 22 are etched away using a laser to form a second opening 52.

[0087] At this step, the etching region 23 is provided on the first transmission layer 20. The etching region 23 has the particle 41 remaining after the second passivation layer 31 and the second doped layer 32 are etched using a laser.

[0088] Further, the plane 231 of the etching region is lower than the plane of the first transmission layer 20 away from the silicon substrate 10, which thins the first doped layer 22. The thinning of the first doped layer 22 reduces the parasitic absorption of the first doped layer 22, which is beneficial to improve the conversion efficiency.

[0089] Further, as shown in FIG. 9, a side view of the cross section of the opening region after the second opening 52 is formed using a laser process is shown. The total thickness of the first passivation layer 21 and a portion of the first doped layer 22 is 90 nm. A green laser is used, and the wavelength of the laser is 532 nm. The energy used is 53 μJ.

[0090] The particle 41 in the form of a melt is formed on the etching region 23. The etching region 23 is tested using a scanning electron microscope (SEM). The maximum length of the particle 41 is more concentrated in the range of 10 nm. The particle 41 in the range of 10 nm or less can increase the backside reflection of the frontside transmitted light.

[0091] At step 105, as shown in FIG. 5, a transparent conductive layer 40 is deposited on one side of the first surface 11 of the silicon substrate 10.

[0092] In this step, a physical vapor deposition (PVD) device can be used to deposit a transparent conductive layer 40 on the first doped layer 22 and the second doped layer 32. The thickness of the transparent conductive layer 40 ranges from 20 nm to 200 nm.

[0093] As shown in FIG. 10, a test image is shown after the solar cell is finished. In the test image, the surface of the first doped layer 22 has particles 41.

[0094] Step 106, as shown in FIG. 6, etching part of the transparent conductive layer 40 to form a third opening 53.

[0095] In this step, photolithography can be used to remove part of the transparent conductive layer 40 in the insulating region to form a third opening 53. The third opening 53 insulates the N region and the P region.

[0096] Step 107, as shown in FIG. 7, using screen printing to prepare a first electrode 61 on the transparent conductive layer 40 corresponding to the N region and a second electrode 62 on the transparent conductive layer 40 corresponding to the P region.

[0097] The first electrode 61 and the second electrode 62 are both metal electrodes, for example, the materials of the first electrode 61 and the second electrode 62 both include silver.

[0098] Embodiment Two

[0099] The difference between the embodiment one and the embodiment two is the difference in the type of the solar cell: the material of the first passivation layer 21 and the material of the second passivation layer 31 both include intrinsic amorphous silicon, and the material of the first doped layer 22 and the material of the second doped layer 32 both include one or more of doped polycrystalline silicon, doped microcrystalline silicon, and doped amorphous silicon. The solar cell formed in the embodiment two is an HBC solar cell. The rest of the embodiment two corresponds to the embodiment one.

[0100] Embodiment Three

[0101] The difference between the embodiment one and the embodiment three is the difference in the type of the solar cell: the material of the first passivation layer 21 and the material of the second passivation layer 31 both include silicon oxide, and the material of the first doped layer 22 and the material of the second doped layer 32 both include doped polycrystalline silicon. The solar cell formed in the embodiment three is a TBC solar cell. The rest of the embodiment three corresponds to the embodiment one.

[0102] Embodiment Four

[0103] The difference between the embodiment one and the embodiment four is the difference of the battery type: the material of the first passivation layer 21 comprises intrinsic amorphous silicon, the material of the first doped layer 22 comprises one of doped polysilicon, doped microcrystalline silicon, doped amorphous silicon; and the material of the second passivation layer 31 comprises silicon oxide, the material of the second doped layer 32 comprises doped polysilicon. The solar cell formed in the embodiment four is a joint passivation back contact cell. The rest of the embodiment four and the embodiment one are the same.

[0104] Embodiment five

[0105] The difference between the embodiment one and the embodiment five is the difference of the energy of the laser, the rest of the embodiment five and the embodiment one are the same.

[0106] As shown in Fig. 10, which shows the test image of the solar cell after the transparent conductive layer 40 is plated, it can still be seen that the surface of the first doped layer 22 has the particles 41.

[0107] Comparative example

[0108] The difference between the embodiment one and the comparative example is that there is no particle 41 on the first doped layer 22, i.e. the first doped layer 22 has no particle, the rest of the comparative example and the embodiment one are the same.

[0109] The performance test is carried out on 1000 solar cells formed in the embodiment one and 1000 solar cells formed in the comparative example under the same test conditions, and the test results are shown in Table 1 below.

[0110] In Table 1, the data of the embodiment one is the arithmetic average of the test results of the 1000 solar cells corresponding to the embodiment one, and the data of the comparative example is the arithmetic average of the test results of the 1000 solar cells corresponding to the comparative example. In Table 1, Jsc represents the short-circuit current density of the solar cell, Voc represents the open-circuit voltage of the solar cell, FF represents the fill factor of the solar cell, and Eff represents the photoelectric conversion efficiency of the solar cell. From the above Table 1, it can be seen that the photoelectric conversion efficiency of the embodiment one is higher than that of the comparative example. The main reason is that in the embodiment one, the laser etches the second passivation layer 31 and the second doped layer 32 in the second opening 52 to form the particles 41 in the first transmission layer 20, and in addition, the laser etching thins part of the first doped layer 22 in the second opening 52. The particles 41 can increase the back reflection of the front transmitted light and improve the light absorption efficiency. In addition, the thinning of part of the first doped layer 22 can reduce the parasitic absorption of the first doped layer 22, which is beneficial to improve the conversion efficiency.

[0111] It is to be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily implying any actual relationship or order between such entities or actions. Also, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0112] Each of the various embodiments in the present application is described in a related manner, and the same or similar parts among the various embodiments can be referred to each other. Each of the various embodiments focuses on the difference from other embodiments. For the embodiments of the apparatus, electronic device, computer readable storage medium, and computer program product containing instructions, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments.

[0113] The above only describes the preferred embodiments of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A solar cell, characterized by, The solar cell comprises a silicon substrate, a first transport layer and a second transport layer, a first surface of the silicon substrate is provided with the first transport layer and the second transport layer, and the first transport layer and the second transport layer are arranged at intervals; The first transport layer is provided with an etching region, a plane where the etching region of the first transport layer is located is lower than or flush with a plane of the first transport layer away from the silicon substrate; and / or, the second transport layer is provided with an etching region, a plane where the etching region of the second transport layer is located is lower than or flush with a plane of the second transport layer away from the silicon substrate; The etching region has particulate matter.

2. The solar cell according to claim 1, characterized in that, In a top view of the solar cell, a maximum length of the particulate matter is less than 50 nm, or less than 20 nm, or less than 15 nm, or the maximum length of the particulate matter ranges from 5 nm to 10 nm.

3. The solar cell according to claim 1, characterized in that, The etching region has a plurality of the particulate matter, and an area coverage of the particulate matter on the etching region ranges from 0.01% to 60%.

4. The solar cell of claim 1, wherein The particulate matter comprises a silicon element; or, the particulate matter comprises a silicon element and a doping element, wherein a type of the doping element comprised by the particulate matter is different from a type of the doping element in the transport layer where the particulate matter is located.

5. The solar cell of claim 1, wherein The particulate matter comprises silicon particles in a molten state.

6. The solar cell of claim 1, wherein In a top view of the solar cell, the particulate matter is at least one of a circular shape, an elliptical shape, and an irregular shape.

7. The solar cell of claim 1, wherein A depth at which the particulate matter is embedded in a plane where the etching region is located ranges from 0 nm to 50 nm.

8. The solar cell of claim 1, wherein, In a thickness direction of the solar cell, 10% to 100% of the particulate matter is embedded in the plane where the etching region is located.

9. The solar cell of claim 1, wherein, The etching region is arranged in the first transport layer, and an area of the etching region accounts for 90% or less of an area of the first transport layer; and / or, The etching region is arranged in the second transport layer, and an area of the etching region accounts for 90% or less of an area of the second transport layer.

10. The solar cell of claim 1, wherein, A plane where the etching region of the first transport layer is located has a height difference D from a plane of the first transport layer away from the silicon substrate, and / or a plane where the etching region of the second transport layer is located has a height difference D from a plane of the second transport layer away from the silicon substrate; 0 nm≤D≤100 nm.

11. The solar cell of claim 1, wherein The particulate matter is formed by laser etching.

12. The solar cell of claim 1, wherein, The first transport layer comprises a first passivation layer and a first doping layer arranged in a stack, the first passivation layer is connected to the first surface and the first doping layer; the second transport layer comprises a second passivation layer and a second doping layer arranged in a stack, the second passivation layer is connected to the first surface and the second doping layer; one of the first doping layer and the second doping layer is an N-type doping layer, and the other of the first doping layer and the second doping layer is a P-type doping layer.

13. The solar cell of claim 1, wherein, An end portion of the first transport layer close to the second transport layer and an end portion of the second transport layer close to the first transport layer are arranged in a stack to form a stacked portion; The solar cell further comprises a transparent conductive layer connected to at least part of the surface of the first transport layer facing away from the silicon substrate and connected to at least part of the surface of the second transport layer facing away from the silicon substrate, and the transparent conductive layer has a third opening for breaking the electrical connection between the first transport layer and the second transport layer.

14. The solar cell of claim 1, wherein, The solar cell further comprises a transparent conductive layer connected to at least part of the surface of the first transport layer facing away from the silicon substrate and connected to at least part of the surface of the second transport layer facing away from the silicon substrate, and the transparent conductive layer has a third opening for breaking the electrical connection between the first transport layer and the second transport layer. The solar cell further comprises a transparent conductive layer connected to at least part of the surface of the first transport layer facing away from the silicon substrate and connected to at least part of the surface of the second transport layer facing away from the silicon substrate, and the transparent conductive layer has a third opening for breaking the electrical connection between the first transport layer and the second transport layer.

15. A photovoltaic module, characterized by, The photovoltaic module comprises a cover plate, a back plate, and a solar cell disposed between the cover plate and the back plate; the solar cell comprises the solar cell according to any one of claims 1 to 14.

Images