CN116632074A - Back contact solar cell, preparation method thereof and photovoltaic module - Google Patents
Back contact solar cell, preparation method thereof and photovoltaic module Download PDFInfo
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- CN116632074A CN116632074A CN202310540584.0A CN202310540584A CN116632074A CN 116632074 A CN116632074 A CN 116632074A CN 202310540584 A CN202310540584 A CN 202310540584A CN 116632074 A CN116632074 A CN 116632074A
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- 238000002360 preparation method Methods 0.000 title abstract description 10
- 239000000758 substrate Substances 0.000 claims abstract description 130
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 126
- 239000010703 silicon Substances 0.000 claims abstract description 126
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 125
- 230000005540 biological transmission Effects 0.000 claims abstract description 101
- 238000002161 passivation Methods 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 31
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 20
- 238000005530 etching Methods 0.000 claims description 17
- 239000000463 material Substances 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 6
- 238000009413 insulation Methods 0.000 claims description 6
- 229910021424 microcrystalline silicon Inorganic materials 0.000 claims description 5
- 229910021423 nanocrystalline silicon Inorganic materials 0.000 claims description 5
- 230000007423 decrease Effects 0.000 claims description 2
- 238000000059 patterning Methods 0.000 description 9
- 230000004888 barrier function Effects 0.000 description 8
- 239000000969 carrier Substances 0.000 description 6
- 238000001000 micrograph Methods 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 3
- 230000006798 recombination Effects 0.000 description 3
- 238000005215 recombination Methods 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000002313 adhesive film Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
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- H—ELECTRICITY
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
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- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0352—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
- H01L31/035272—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
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- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
- H01L31/072—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type
- H01L31/0745—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
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- H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
- H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
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Abstract
The application provides a back contact solar cell, a preparation method thereof and a photovoltaic module, and relates to the technical field of photovoltaics. A back contact solar cell comprising: the silicon substrate is respectively positioned on the first transmission layer, the second transmission layer and the insulating layer on the backlight side of the silicon substrate; the first conductive areas, the insulating areas and the second conductive areas are distributed along a first direction; the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region; the insulating layer includes: a third portion located on the second portion; the first side surface of the third portion, which is close to the second conductive region, is inclined in the first direction from the second direction close to the silicon substrate to the second direction away from the silicon substrate, sequentially toward the first conductive region, and one end of the first side surface, which is farthest from the silicon substrate, is closer to the first conductive region than one end of the first side surface, which is closest to the silicon substrate, is in the first direction. The application improves the insulating property and reduces the short circuit problem.
Description
Technical Field
The application relates to the technical field of photovoltaics, in particular to a back contact solar cell, a preparation method thereof and a photovoltaic module.
Background
The back contact solar cell has the advantages that the electrode is arranged on the back surface of the cell, so that the short-circuit current loss can be effectively reduced, and the back contact solar cell has a wide application prospect.
In back contact solar cells, the problem of shorting in the back contact solar cell is usually avoided by providing an insulating layer.
However, in the existing back contact solar cell, a serious short circuit problem still exists, which affects the performance of the back contact solar cell.
Disclosure of Invention
The application provides an existing back contact solar cell, which aims to solve the problem of serious short circuit in the existing back contact solar cell.
In a first aspect of the present application, there is provided a back contact solar cell comprising: the silicon substrate is positioned on the first transmission layer, the second transmission layer and the insulating layer on the backlight side of the silicon substrate; the method comprises the steps of carrying out a first treatment on the surface of the
The backlight side of the silicon substrate includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region; the first conductive region, the insulating region and the second conductive region are distributed along a first direction; the doping type of the first doping layer in the first transmission layer is different from that of the second doping layer in the second transmission layer;
the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region; the insulating layer includes: a third portion located on the second portion; and a first side surface of the third part, which is close to the second conductive area, is inclined in sequence from being close to the silicon substrate to being far away from the silicon substrate along the first direction, wherein one end of the first side surface, which is farthest from the silicon substrate, is closer to the first conductive area than one end of the first side surface, which is closest to the silicon substrate, is closer to the first conductive area in the first direction.
In an embodiment of the application, the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region. The insulating layer has a third portion located on the second portion. In the insulating layer, a first side surface of the third portion, which is close to the second conductive region, is inclined in the direction close to the first conductive region from the direction close to the silicon substrate to the second direction away from the silicon substrate, sequentially in the first direction, and one end of the first side surface, which is farthest from the silicon substrate, is closer to the first conductive region than one end of the first side surface, which is closest to the silicon substrate, is on the first direction. That is, the side surface of the third portion, which is close to the second conductive region, is far away from the end of the silicon substrate, and the opening is larger, so that the second transmission layer is easier to form in the subsequent process of forming the second transmission layer, the second transmission layer is easy to form in the side surface of the third portion, which is close to the fifth portion, in the subsequent process of patterning the second transmission layer and the insulating layer, particularly in the wet patterning process, the second transmission layer formed in the side surface of the third portion, which is close to the fifth portion, is used as a mask for the side surface of the third portion, so that the side surface of the third portion, which is close to the fifth portion, is protected, and the third portion is less damaged in the subsequent patterning process, or is basically undamaged, thereby improving the insulating property and reducing the short circuit problem.
Optionally, the insulating layer further includes: a fourth portion located on the first portion; the area of the orthographic projection of the fourth part on the backlight surface of the first part is smaller than that of the backlight surface of the first part; the fourth portion, along the second direction, decreases in size and increases in size in the first direction.
Optionally, the second conductive region and the first portion are irradiated by laser;
the back contact solar cell further comprises: a first electrode and a second electrode located on a backlight side of the silicon substrate;
the second transmission layer has a fifth portion on the second conductive region and a sixth portion on the fourth portion;
the first electrode is located on a region other than the sixth portion in the first portion, and the second electrode is located on the fifth portion.
Optionally, the first transmission layer and the second transmission layer both comprise a back passivation layer and a doped layer which are stacked; the back passivation layer is closer to the silicon substrate than the doped layer in the first transmission layer and the second transmission layer;
the material of the back passivation layer is selected from the group consisting of: at least one of amorphous silicon, nanocrystalline silicon, and microcrystalline silicon.
Optionally, the ratio of the total area of orthographic projection on the back surface of the silicon substrate to the total area of the back surface of the silicon substrate is: 0.001% to 0.5%.
Optionally, the back contact solar cell further includes: the transparent conductive layer is positioned on the backlight side of the silicon substrate, and the front passivation layer and the front antireflection layer are sequentially positioned on the light-facing surface of the silicon substrate.
In a second aspect of the present application, there is provided a method for manufacturing any one of the aforementioned back contact solar cells, comprising:
providing a substrate; the substrate comprises: the silicon substrate is sequentially positioned on the first transmission layer, the insulating layer and the mask layer on the backlight side of the silicon substrate; the first transmission layer, the insulating layer and the mask layer are all arranged on the whole surface of the backlight side of the silicon substrate; the backlight side of the silicon substrate includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region; the first conductive region, the insulating region and the second conductive region are distributed along a first direction;
opening the mask layer to expose part of the insulating layer, adopting a first etching solution to open the exposed part of the insulating layer and a first transmission layer below the insulating layer to expose part of the backlight surface of the silicon substrate, wherein the first transmission layer is provided with a first part positioned on the first conductive region and a second part positioned on the insulating region, and the insulating layer is provided with a third part positioned on the second part;
removing the rest mask layer, and treating the exposed area of the backlight surface of the silicon substrate by adopting hydrofluoric acid, so that a first side surface, which is close to the second conductive area, of the third part is inclined from being close to the silicon substrate to being far away from the silicon substrate along the first direction in sequence towards being close to the first conductive area, wherein one end, which is farthest from the silicon substrate, of the first side surface is closer to the first conductive area in the first direction than one end, which is closest to the silicon substrate, of the first side surface;
forming a second transmission layer in an exposed area of the backlight surface of the silicon substrate; the first doped layer in the first transport layer is of a different doping type than the second doped layer in the second transport layer.
Optionally, the opening the mask layer includes: and opening the mask layer by adopting laser overlapped by light spots.
Optionally, the forming a second transmission layer on the exposed area of the backlight surface of the silicon substrate includes:
forming a second transmission layer on the exposed area of the backlight surface of the silicon substrate and the rest insulating layer;
the method further comprises the steps of: and (3) opening the film on the second transmission layer by adopting laser with non-overlapping light spots so that the insulation layer is partially exposed, and adopting a second etching solution to form the film on the exposed insulation layer.
In a third aspect of the present application, there is provided a photovoltaic module comprising: a number of the back contact solar cells of any of the preceding claims.
The preparation methods of the photovoltaic module and the back contact solar cell have the same or similar beneficial effects as the back contact solar cell, and in order to avoid repetition, the description is omitted here.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments of the present application will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 shows a schematic structure of a back contact solar cell according to an embodiment of the present application;
FIG. 2 illustrates a partial front view of a third portion of a barrier layer, and a first doped layer, in accordance with an embodiment of the present application;
FIG. 3 shows a partial electron microscope image of a third portion of a barrier layer, and a first transmission layer, in an embodiment of the application;
FIG. 4 illustrates a partial front view of a fourth portion of a barrier layer, and a first doped layer, in accordance with an embodiment of the present application;
FIG. 5 shows a partial electron microscope image of a fourth portion of a barrier layer and a second transmission layer in an embodiment of the application;
FIG. 6 is a flow chart showing a method for fabricating a back contact solar cell in accordance with an embodiment of the present application;
fig. 7 to 13 are schematic views showing the structure of a manufacturing step of a back contact solar cell in an embodiment of the present application.
Description of the drawings: 1-silicon substrate, 2-back passivation layer, 3-first doped layer, 4-second doped layer, 5-first electrode, 6-second electrode, 7-insulating layer, 71-first side, 8-transparent conductive layer, 9-front passivation layer, 10-front antireflection layer, 11-mask layer.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The inventor finds that in the existing back contact solar cell, a serious short circuit problem exists, and the main reason that the performance of the back contact solar cell is affected is as follows: the part of the insulating layer located in the insulating region is subjected to isotropic etching by the etching solution, and a structure which is firstly reduced and then increased is formed from the part close to the silicon substrate to the direction far away from the silicon substrate, that is, one end of the insulating layer located in the insulating region, which is farthest from the silicon substrate, protrudes more than the upper part of the insulating layer, then a second transmission layer is formed on the second conductive region and the insulating layer, in the process of forming the second transmission layer, due to shielding of one end of the protruding part of the insulating layer located in the insulating region, the part of the insulating layer located in the insulating region is close to the side surface of the second conductive region, the second transmission layer is difficult to form, and in the subsequent patterning process, the part of the insulating layer located in the insulating region is close to the side surface of the second conductive region, and is easy to damage due to the fact that the second transmission layer is not protected, the structural integrity of the part of the insulating layer located in the insulating region is further damaged, and the insulating effect of the insulating layer is further reduced, so that in the back contact solar cell is seriously shorted, and the performance of the back contact solar cell is affected.
Fig. 1 shows a schematic structure of a back contact solar cell according to an embodiment of the present application. Referring to fig. 1, the back contact solar cell includes: the doping type of the silicon substrate 1 is not particularly limited to the silicon substrate 1. For example, the silicon substrate 1 may be an N-type doped silicon substrate, or may be a P-type doped silicon substrate. In the embodiment of the present application, this is not particularly limited. The silicon substrate 1 includes a light-facing surface and a backlight surface, which are relatively distributed. The backlight surface of the silicon substrate 1 refers to the surface of the silicon substrate 1 close to the electrode in the back contact solar cell. The type of the back contact solar cell may be a back contact heterojunction cell (Hetero-Junction Back Contact, HBC) or the like, and is not particularly limited.
The backlight side of the silicon substrate 1 includes a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region. Referring to fig. 1, the first conductive region, the insulating region, and the second conductive region are distributed along a first direction L. In the back contact solar cell, the portions of the back surface of the silicon substrate 1, where the front projections fall into the first conductive regions, are used for separating and transporting the first carriers, and the portions of the back surface of the silicon substrate 1, where the front projections fall into the second conductive regions, are used for separating and transporting the second carriers, where the types of the first carriers and the second carriers are different, i.e., one is a hole, and the other is an electron. In the back contact solar cell, the area of the conductive region in the emitter is larger than that of the conductive region in the back field, so that the power generation efficiency of the back contact solar cell is improved. Specifically, the emitter is mainly used for separating and transmitting minority carriers, and the area of the conductive area is large, so that the emitter is larger, collection of minority carriers is facilitated, and the like, and therefore the power generation efficiency of the back contact solar cell is improved.
Referring to fig. 1, a region between the broken line L1 and the broken line L2 in the backlight surface of the silicon substrate 1 is a first conductive region, a region between the broken line L3 and the broken line L4 in the backlight surface of the silicon substrate 1 is a second conductive region, a region between the broken line L2 and the broken line L3 in the backlight surface of the silicon substrate 1 is an insulating region, and the insulating region is between the first conductive region and the second conductive region. The first conductive region, the insulating region and the second conductive region are distributed along the first direction L. Note that the broken lines L1, L2, L3, and L4 in fig. 1 are only schematic for illustrating the first conductive region, the second conductive region, and the insulating region, and are not actually present in the back contact solar cell.
Referring to fig. 1, the back contact solar cell further includes: a first transmission layer and a second transmission layer positioned on the backlight side of the silicon substrate 1. The first transport layer and the second transport layer are alternately arranged. Alternatively, the first transport layer includes a back passivation layer 2 and a first doped layer 3 that are stacked, the back passivation layer 2 being closer to the silicon substrate 1 than the first doped layer 3. The second transport layer comprises a back passivation layer 2 and a second doped layer 4, the back passivation layer 2 being closer to the silicon substrate 1 than the second doped layer 4. The doping types of the second doped layer 4 and the first doped layer 3 are opposite, namely, one is a P-type doped layer and the other is an N-type doped layer. Optionally, the material of the back passivation layer 2 may be at least one of amorphous silicon, microcrystalline silicon, and nanocrystalline silicon, where the back passivation layer 2 of the above material may reduce carrier recombination at the interface, so that the back contact solar cell has a higher open circuit voltage. For example, the back passivation layer 2 may be at least one of intrinsic amorphous silicon, intrinsic microcrystalline silicon, and intrinsic nanocrystalline silicon, and for another example, the back passivation layer 2 may be at least one of intrinsic hydrogenated amorphous silicon, intrinsic hydrogenated microcrystalline silicon, and intrinsic hydrogenated nanocrystalline silicon. The materials of the first doped layer 3 and the second doped layer 4 may be doped polysilicon or the like. It should be noted that whether the material and thickness of the back passivation layer 2 in the first transmission layer and the back passivation layer 2 in the second transmission layer are the same is not particularly limited.
Referring to fig. 1, the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region. That is, the portion of the first transport layer located between the broken line L1 and the broken line L2 is the first portion. The portion of the first transmission layer located between the dashed line L2 and the dashed line L3 is the second portion.
The insulating layer 7 includes: the third portion located on the second portion of the first transmission layer, that is, the portion of the insulating layer 7 located between the broken line L2 and the broken line L3 is the third portion. The third portion is mainly electrically isolated and short-circuited is avoided.
In view of the foregoing, in the embodiment of the present application, referring to fig. 1, in the third portion of the insulating layer 7 located in the insulating region, the first side 71 close to the second conductive region is inclined in the direction close to the first conductive region in order from the direction close to the silicon substrate 1 to the second direction L5 away from the silicon substrate 1 along the aforementioned first direction L, and the end of the first side 71 furthest from the silicon substrate 1 is closer to the first conductive region than the end of the first side 71 closest to the silicon substrate 71 is. Fig. 2 shows a partial schematic front view of a third portion of a barrier layer and a first doped layer in an embodiment of the present application. Fig. 3 shows a partial electron microscope image of a third portion of a barrier layer and a first transmission layer in an embodiment of the application. The first transmission layer is on the left side in fig. 3, and the third portion is on the right side. Referring to fig. 1, 2 and 3, that is, the opening of the end of the first side 71 furthest from the silicon substrate 1 is larger, the second transmission layer is easier to form during the formation of the second transmission layer, the second transmission layer is easy to form on the first side 71, and the second transmission layer formed on the first side 71 of the third portion during the subsequent patterning of the second transmission layer and the insulating layer 7, especially during the wet patterning, can be used as a mask of the third portion to protect the third portion, so that the third portion is less damaged or basically not damaged during the subsequent patterning, thereby improving the insulating property and reducing the short circuit problem.
Alternatively, the material of the insulating layer 7 may be selected from: at least one of silicon nitride, silicon oxynitride, silicon oxide, and silicon carbide, the material of the insulating layer 7 is easy to obtain, and the insulating property is good.
Optionally, referring to fig. 1, the insulating layer 7 includes: the fourth portion located on the first portion of the first transmission layer, that is, the portion of the insulating layer 7 located between the broken line L1 and the broken line L2 is the fourth portion. The area of the orthographic projection of the fourth portion on the backlight surface of the first portion is smaller than the area of the backlight surface of the first portion, and the difference between the two is not particularly limited. Fig. 4 shows a partial schematic front view of a fourth portion of a barrier layer and a first doped layer in an embodiment of the present application. Fig. 5 shows a partial electron microscope image of a fourth portion of a barrier layer and a second transmission layer in an embodiment of the application. The second transmission layer is shown on the left side and the fourth portion is shown on the right side in fig. 5. Referring to fig. 1, 4 and 5, the fourth portion has a size in the first direction L along the second direction L5, which is decreased and then increased. The fourth part of the shape is readily available due to the isotropy of the etching solution.
Optionally, the second conductive region and the first portion are irradiated by the laser, so that patterning of the first transmission layer and the second transmission layer is performed by means of the laser, and the process is simple. Referring to fig. 1, the second transmission layer has a fifth portion located on the second conductive region, a sixth portion located on the fourth portion of the insulating layer 7, and a seventh portion located on the insulating region. That is, the portion of the second transmission layer located between the broken line L3 and the broken line L4 is the fifth portion. The portion of the second transmission layer located between the dashed line L2 and the dashed line L3 is the seventh portion. The portion of the second transmission layer located between the dashed line L1 and the dashed line L2 is the sixth portion. The above structures of the first transmission layer and the second transmission layer indicate that the preparation process of the second transmission layer is later than that of the first transmission layer, the first transmission layer has no residue in the second conductive region, and indicate that laser spots overlap in the process of patterning the first transmission layer by laser, and the back passivation layer 2 positioned in the second conductive region in the first transmission layer is in a final battery structure without reservation and protection of passivation performance, so that laser film opening of the first transmission layer is not required, high temperature influence of instantaneous high temperature on the back passivation layer 2 positioned in the second conductive region in the first transmission layer is not required, a laser process window can be improved, and yield and production efficiency are improved. The second transmission layer is provided with a sixth part positioned in the first conductive area, which means that laser spots are not overlapped in the process of opening the second transmission layer by laser, the sixth part is left by the fact that the laser spots are not overlapped, and because the laser spots are not overlapped, the influence of the instantaneous high temperature of the laser opening on the back passivation layer 2 in the first part is small, the passivation performance of the back passivation layer 2 in the first part is protected, carrier recombination at an interface can be reduced, and the back contact solar cell has higher open circuit voltage.
The back contact solar cell further comprises: a first electrode 5 and a second electrode 6 located on the backlight side of the silicon substrate 1. The first electrode 5 is located in a first part of the first transmission layer, on a region other than the sixth part, and the second electrode 6 is located on a fifth part of the second transmission layer on the second conductive region.
Optionally, the sixth portion of the second transmission layer located in the first conductive area, where the total area of orthographic projections on the back surface of the silicon substrate 1 is the ratio of the total area of the back surface of the silicon substrate 1 is: from 0.001% to 0.5%, in this range, a good balance is achieved between the protective effect on the passivation properties of the back passivation layer 2 in the first transport layer, and the loss of electrical properties caused by this sixth part.
For example, the ratio of the total area of orthographic projection of the sixth portion on the back surface of the silicon substrate 1 to the total area of the back surface of the silicon substrate 1 is: 0.001%, or 0.003%, or 0.01%, or 0.04%, or 0.09%, or 0.1%, or 0.103%, or 0.221%, or 0.278%, or 0.3%, or 0.361%, or 0.41%, or 0.411%, or 0.5%.
Optionally, referring to fig. 1, the back contact solar cell further includes: the transparent conductive layer 8 located on the backlight side of the silicon substrate 1, the front passivation layer 9 and the front antireflection layer 10 located on the light facing surface of the silicon substrate 1 in sequence, the transparent conductive layer 8 includes: a portion between the first electrode 5 and said first portion, and a portion between the second electrode 6 and the fifth portion.
The application also provides a preparation method of any of the back contact solar cells, and fig. 6 shows a flowchart of a preparation method of the back contact solar cell in the embodiment of the application. Referring to fig. 6, the method may include the steps of:
step 101, providing a substrate; the substrate comprises: the silicon substrate is sequentially positioned on the first transmission layer, the insulating layer and the mask layer on the backlight side of the silicon substrate; the first transmission layer, the insulating layer and the mask layer are all arranged on the whole surface of the backlight side of the silicon substrate; the backlight side of the silicon substrate includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region; the first conductive region, the insulating region, and the second conductive region are distributed along a first direction.
Fig. 7 to 13 are schematic views showing the structure of a manufacturing step of a back contact solar cell in an embodiment of the present application.
Referring to fig. 7, the back surface of the silicon substrate 1 may be a lower side surface. For example, the silicon substrate 1 may be an N-type silicon substrate. The backlight surface of the silicon substrate 1 may be first textured. Referring to fig. 8, a first transmission layer is formed on the entire surface of a backlight surface of a silicon substrate 1. For example, hydrogenated amorphous silicon may be deposited as the back passivation layer 2, the phosphorus doped second doped layer 3, using PECVD (Plasma Enhanced Chemical Vapor Deposition ). An entire insulating layer 7 and an entire mask layer 11 are formed on the first transfer layer. The material of the insulating layer 7 here may be at least one of silicon nitride, silicon oxide, silicon oxynitride, silicon carbide, and the like. The mask layer 11 is present as a mask for the insulating layer 7 during a subsequent wet etching process.
The backlight side of the silicon substrate 1 includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region.
Step 102, performing film opening on the mask layer to expose a part of the insulating layer, performing film opening on the exposed part of the insulating layer and a first transmission layer below the insulating layer by using a first etching solution to expose a backlight surface part of the silicon substrate, wherein the first transmission layer is provided with a first part positioned on the first conductive region and a second part positioned on the insulating region, and the insulating layer is provided with a third part positioned on the second part.
Specifically, referring to fig. 9, the mask layer 11 is opened so that a portion of the insulating layer 7 is exposed, and referring to fig. 10 and 11, a first etching solution is used to open the exposed portion of the insulating layer 7 and a first transmission layer below the exposed portion of the insulating layer 7 so that a backlight portion of the silicon substrate is exposed, where the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region, and the insulating layer 7 has a third portion located on the second portion.
The first etching solution may be one or more etching solutions, for example, hydrofluoric acid is used to first film the exposed portion of the insulating layer 7, so that the portion of the first transmission layer below the exposed portion is exposed. And then etching the exposed part of the first transmission layer by adopting alkaline etching solution. The isotropic etching by hydrofluoric acid causes the insulating layer 7 to be etched inward, that is, to be over-etched, and as shown in fig. 10, the insulating layer 7 is formed to have a shape in which the dimension in the first direction L is decreased and then increased along the second direction L5 at the opening portion.
Optionally, in the foregoing step 102, the opening the mask layer 11 may include: and (5) opening the mask layer 7 by adopting laser with overlapped light spots. Here the spots of the laser light overlap, so that the portions of the mask layer 11 that are located in the second conductive areas can be completely removed.
And 103, removing the residual mask layer, and treating the exposed area of the backlight surface of the silicon substrate by adopting hydrofluoric acid, so that a first side surface, which is close to the second conductive area, in the third part is inclined from being close to the silicon substrate to being far away from the silicon substrate along the first direction in sequence towards being close to the first conductive area, wherein one end, which is farthest from the silicon substrate, of the first side surface is closer to the first conductive area in the first direction than one end, which is closest to the silicon substrate, of the first side surface is closer to the first conductive area in the first direction.
Referring to fig. 11, the remaining mask layer 11 is removed, and the exposed area of the back surface of the silicon substrate 1 is treated with hydrofluoric acid to form an H dangling bond, and during the treatment of hydrofluoric acid, since the side of the insulating layer 7 away from the silicon substrate 1 is not protected by the mask layer 11, but is etched with hydrofluoric acid, and the side of the insulating layer 7 near the silicon substrate 1 has the remaining first transmission layer as protection, and is not etched substantially with hydrofluoric acid, so that the first side 71 near the second conductive area in the third portion is inclined in the direction near the first conductive area sequentially from near the silicon substrate 1 to the second direction L5 away from the silicon substrate 1 along the first direction L1, and the end farthest from the silicon substrate 1 is closer to the first conductive area than the end closest to the silicon substrate 1 on the first side 71 in the first direction L.
104, forming a second transmission layer in an exposed area of the backlight surface of the silicon substrate; the first doped layer in the first transport layer is of a different doping type than the second doped layer in the second transport layer.
Referring to fig. 12 and 13, a second transmission layer is formed on an exposed area of the back surface of the silicon substrate 1. The doping type of the first doped layer 3 in the first transport layer is different from the doping type of the second doped layer 4 in the second transport layer.
Optionally, the foregoing step 104 may include: referring to fig. 12, an entire second transmission layer is formed on the exposed area of the back surface of the silicon substrate 1 and the remaining insulating layer 7. The method further comprises the steps of: referring to fig. 13, the second transmission layer is subjected to film opening by using laser light with non-overlapping spots so that the insulation layer is partially exposed, and the exposed portion of the insulation layer 7 is subjected to film opening by using a second etching solution. In the process of opening the second transmission layer by laser, laser spots are not overlapped, so that the influence of the instantaneous high temperature of the laser film opening on the back passivation layer 2 in the first part is small, the passivation performance of the back passivation layer 2 in the first part is protected, carrier recombination at an interface can be reduced, and the back contact solar cell has higher open circuit voltage.
The second etching solution here may be hydrofluoric acid or the like. Due to the isotropy of the second etching solution, an insulating layer may be formed in a fourth portion on the first portion, the dimension in the aforementioned first direction L being decreased and then increased along the second direction L5.
Referring to fig. 1, the preparation method may further include: in the first part of the first transport layer, the first electrode 5 is provided on the area other than the sixth part, and the second electrode 6 is provided on the fifth part of the second transport layer.
Optionally, referring to fig. 1, before the first electrode 5 and the second electrode 6 are provided, the method may further include: the transparent conductive layer 8, the front passivation layer 9 and the front antireflection layer 10 are formed over the entire surface, and then the transparent conductive layer 8 is blocked. For example, PECVD may be used to deposit the front passivation layer 10 and the front anti-reflection layer 10 on the entire surface of the light-facing surface of the silicon substrate 1. The deposition of the transparent conductive layer 8 is performed by PVD (Physical Vapor Deposition )/RPD (Reactive Plasma Deposition, reactive plasma deposition) or the like. The first electrode 5 and the second electrode 6 can be prepared by silk screen printing, electroplating and the like.
The application also provides a photovoltaic module, which comprises a plurality of back contact solar cells. The photovoltaic module may further include: front packaging adhesive film and cover plate positioned on the light-facing side of the back contact solar cell, and rear packaging adhesive film and back plate positioned on the backlight side of the back contact solar cell.
The photovoltaic module and the preparation method of the back contact solar cell have the same or similar beneficial effects as any one of the back contact solar cells, and in order to avoid repetition, the description is omitted here.
It should be noted that, for simplicity of description, the method embodiments are shown as a series of acts, but it should be understood by those skilled in the art that the embodiments are not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred, and that the acts are not necessarily all required in accordance with the embodiments of the application.
It should be noted that, in this document, 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 may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) comprising instructions for causing a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the method according to the embodiments of the present application.
The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are to be protected by the present application.
Claims (10)
1. A back contact solar cell, comprising: the silicon substrate is positioned on the first transmission layer, the second transmission layer and the insulating layer on the backlight side of the silicon substrate;
the backlight side of the silicon substrate includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region; the first conductive region, the insulating region and the second conductive region are distributed along a first direction; the doping type of the first doping layer in the first transmission layer is different from that of the second doping layer in the second transmission layer;
the first transmission layer has a first portion located on the first conductive region and a second portion located on the insulating region; the insulating layer includes: a third portion located on the second portion; and a first side surface of the third part, which is close to the second conductive area, is inclined in sequence from being close to the silicon substrate to being far away from the silicon substrate along the first direction, wherein one end of the first side surface, which is farthest from the silicon substrate, is closer to the first conductive area than one end of the first side surface, which is closest to the silicon substrate, is closer to the first conductive area in the first direction.
2. The back contact solar cell of claim 1, wherein the insulating layer further comprises: a fourth portion located on the first portion; the area of the orthographic projection of the fourth part on the backlight surface of the first part is smaller than that of the backlight surface of the first part; the fourth portion, along the second direction, decreases in size and increases in size in the first direction.
3. The back contact solar cell of claim 2, wherein the second conductive region and the first portion are both irradiated with laser light;
the back contact solar cell further comprises: a first electrode and a second electrode located on a backlight side of the silicon substrate;
the second transmission layer has a fifth portion on the second conductive region and a sixth portion on the fourth portion;
the first electrode is located on a region other than the sixth portion in the first portion, and the second electrode is located on the fifth portion.
4. The back contact solar cell of any one of claims 1-3, wherein the first and second transport layers each comprise a back passivation layer and a doped layer in a stacked arrangement; the back passivation layer is closer to the silicon substrate than the doped layer in the first transmission layer and the second transmission layer;
the material of the back passivation layer is selected from the group consisting of: at least one of amorphous silicon, nanocrystalline silicon, and microcrystalline silicon.
5. The back contact solar cell of claim 3, wherein the six portions, in total area of orthographic projection of the back surface of the silicon substrate, are in proportion to the total area of the back surface of the silicon substrate: 0.001% to 0.5%.
6. The back contact solar cell of any one of claims 1 to 3, further comprising: the transparent conductive layer is positioned on the backlight side of the silicon substrate, and the front passivation layer and the front antireflection layer are sequentially positioned on the light-facing surface of the silicon substrate.
7. A method of manufacturing the back contact solar cell of any one of claims 1 to 6, comprising:
providing a substrate; the substrate comprises: the silicon substrate is sequentially positioned on the first transmission layer, the insulating layer and the mask layer on the backlight side of the silicon substrate; the first transmission layer, the insulating layer and the mask layer are all arranged on the whole surface of the backlight side of the silicon substrate; the backlight side of the silicon substrate includes: a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region; the first conductive region, the insulating region and the second conductive region are distributed along a first direction;
opening the mask layer to expose part of the insulating layer, adopting a first etching solution to open the exposed part of the insulating layer and a first transmission layer below the insulating layer to expose part of the backlight surface of the silicon substrate, wherein the first transmission layer is provided with a first part positioned on the first conductive region and a second part positioned on the insulating region, and the insulating layer is provided with a third part positioned on the second part;
removing the rest mask layer, and treating the exposed area of the backlight surface of the silicon substrate by adopting hydrofluoric acid, so that a first side surface, which is close to the second conductive area, of the third part is inclined from being close to the silicon substrate to being far away from the silicon substrate along the first direction in sequence towards being close to the first conductive area, wherein one end, which is farthest from the silicon substrate, of the first side surface is closer to the first conductive area in the first direction than one end, which is closest to the silicon substrate, of the first side surface;
forming a second transmission layer in an exposed area of the backlight surface of the silicon substrate; the first doped layer in the first transport layer is of a different doping type than the second doped layer in the second transport layer.
8. The method for manufacturing a back contact solar cell according to claim 7, wherein the opening the mask layer comprises: and opening the mask layer by adopting laser overlapped by light spots.
9. The method for manufacturing a back contact solar cell according to claim 7 or 8, wherein forming a second transmission layer on an exposed area of the back surface of the silicon substrate comprises:
forming a second transmission layer on the exposed area of the backlight surface of the silicon substrate and the rest insulating layer;
the method further comprises the steps of: and (3) opening the film on the second transmission layer by adopting laser with non-overlapping light spots so that the insulation layer is partially exposed, and adopting a second etching solution to form the film on the exposed insulation layer.
10. A photovoltaic module comprising a plurality of back contact solar cells according to any one of claims 1 to 6.
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| CN117712212A (en) * | 2024-02-05 | 2024-03-15 | 天合光能股份有限公司 | Solar cell and method for manufacturing solar cell |
| CN117712212B (en) * | 2024-02-05 | 2024-04-23 | 天合光能股份有限公司 | Solar cell and method for manufacturing solar cell |
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