CN210926047U

CN210926047U - Heterojunction solar cell piece, pile of tile subassembly

Info

Publication number: CN210926047U
Application number: CN201921823263.7U
Authority: CN
Inventors: 王秀鹏; 王月斌; 蒋卫朋
Original assignee: Chengdu Yefan Science and Technology Co Ltd
Current assignee: Tongwei Solar Jintang Co Ltd
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2020-07-03
Anticipated expiration: 2029-10-28

Abstract

The utility model relates to a heterojunction solar wafer, shingling subassembly. The heterojunction solar cell sheet comprises a substrate sheet and electrodes disposed on top and bottom surfaces of the substrate sheet, the substrate sheet comprising a central layer and a plurality of light-transmissive conductive layers. The plurality of light-transmitting conductive layers are stacked in a direction perpendicular to the center layer on the top and bottom sides of the center layer, and the light transmittance of each light-transmitting conductive layer increases in a direction from the center layer to the electrode. According to the utility model discloses, solar cell's electrically conductive transparent area is provided with the printing opacity conducting layer of a plurality of light transmissivity gradual changes, and such setting can improve aspects such as the carrier skew rate, light transmissivity and the electric conductivity of heterojunction solar wafer, avoids the filling factor to hang down, the emergence of the lower problem of the electric current that opens circuit, makes heterojunction solar wafer have higher photoelectric conversion rate.

Description

Heterojunction solar cell piece, pile of tile subassembly

Technical Field

The utility model relates to an energy field especially relates to a heterojunction solar wafer, shingling subassembly.

Background

With the increasing consumption of conventional fossil energy such as global coal, oil, natural gas and the like, the ecological environment is continuously deteriorated, and particularly, the sustainable development of the human society is seriously threatened due to the increasingly severe global climate change caused by the emission of greenhouse gases. Various countries in the world make respective energy development strategies to deal with the limitation of conventional fossil energy resources and the environmental problems caused by development and utilization. Solar energy has become one of the most important renewable energy sources by virtue of the characteristics of reliability, safety, universality, long service life, environmental protection and resource sufficiency, and is expected to become a main pillar of global power supply in the future.

In a new energy revolution process, the photovoltaic industry in China has grown into a strategic emerging industry with international competitive advantages. However, the development of the photovoltaic industry still faces many problems and challenges, and the conversion efficiency and reliability are the biggest technical obstacles restricting the development of the photovoltaic industry, while the cost control and the scale-up are economically restricted.

At present, the heterojunction solar cell has a series of advantages of high conversion efficiency, short manufacturing process flow, thin silicon wafer, low temperature coefficient, no light attenuation, double-sided power generation, high double-sided efficiency and the like, and is praised as the next generation ultra-high efficiency solar cell technology with the best industrialization potential. However, the heterojunction solar cell technology has certain difficulty in realizing large-scale development: on one hand, the manufacturing cost of the heterojunction solar cell is relatively high, and on the other hand, when the heterojunction solar cell is packaged by adopting a conventional packaging technology, the stability of the tensile force of a welding strip is difficult to control, and the heterojunction solar cell cannot adopt the processes of high-temperature welding and the like of the traditional crystalline silicon cell, needs a low-temperature welding process and a low-temperature material, so that the packaging process difficulty is high.

The shingled assembly utilizes the electrical principle of low current and low loss (the power loss of the photovoltaic assembly is in a direct proportional relation with the square of the working current) so as to greatly reduce the power loss of the assembly. And secondly, the inter-cell distance region in the cell module is fully utilized to generate electricity, so that the energy density in unit area is high. In addition, the conventional photovoltaic metal welding strip for the assembly is replaced by the conductive adhesive with the elastomer characteristic at present, the photovoltaic metal welding strip shows higher series resistance in the whole battery, and the stroke of a current loop of the conductive adhesive is far smaller than that of a welding strip, so that the laminated assembly becomes a high-efficiency assembly, and meanwhile, the outdoor application reliability is more excellent than that of the conventional photovoltaic assembly, and the laminated assembly avoids stress damage of the metal welding strip to the interconnection position of the battery and other confluence areas. Especially, under the dynamic (load action of natural world such as wind, snow and the like) environment with alternating high and low temperatures, the failure probability of the conventional assembly which is interconnected and packaged by adopting the metal welding strips is far higher than that of the laminated assembly which is interconnected and cut by adopting the conductive adhesive of the elastomer and packaged by the battery chips.

The mainstream technology of the current tile stack assembly is to use a conductive adhesive to interconnect the cut battery pieces, wherein the conductive adhesive mainly comprises a conductive phase and a bonding phase. The conductive phase mainly comprises precious metals, such as pure silver particles or particles of silver-coated copper, silver-coated nickel, silver-coated glass and the like, and is used for conducting electricity among solar cells, the particle shape and distribution of the conductive phase are based on the requirement of optimal electricity conduction, and at present, more sheet-shaped or sphere-like combined silver powder with D50 being less than 10um is adopted. The adhesive phase is mainly composed of a high molecular resin polymer having weather resistance, and acrylic resin, silicone resin, epoxy resin, polyurethane, and the like are usually selected in accordance with the adhesive strength and weather resistance. In order to enable the conductive adhesive to achieve low contact resistance, low volume resistivity and high adhesion and maintain long-term excellent weather resistance, a conductive adhesive manufacturer can generally complete the design of a conductive phase and an adhesive phase formula, so that the performance stability of the laminated tile assembly under an initial stage environment corrosion test and long-term outdoor practical application is ensured.

If the heterojunction solar cell is packaged by adopting the tiling technology, the problems are solved. The tiling technology adopts the mode that the conductive adhesive is connected with the battery pieces in series, the low-temperature and flexible characteristics of the conductive adhesive and the design of no welding strip can solve the problems of the tension stability and the low-temperature welding of the welding strip. In addition, the heterojunction solar cell technology can adopt thinner silicon wafers, and when the traditional assembly packaging process is adopted, the difficulty of connecting the welding strips in series with the cell pieces is high, and the heterojunction solar cell is influenced by mechanical stress and thermal stress, so that the heterojunction solar cell is easy to break. The laminated assembly is connected with the battery pieces without welding strips, so that the breakage rate in the packaging process can be reduced.

In addition to the above problems, other problems exist with heterojunction solar cells. The passivation layer and the carrier transport layer used in the conventional heterojunction solar cell are amorphous silicon thin films, have very poor conductivity, and in order to lead out emitted electricity, a transparent conductive thin film needs to be plated on the amorphous silicon thin film. Meanwhile, in order to increase the light transmission and reduce the reflection and absorption, the film has high light transmission and anti-reflection characteristics. The transparent conductive film material commonly used at present is

ITO (indium tin oxide), which is not satisfactory for heterojunction cells. In particular, the use of ITO, for example, results in low carrier mobility, poor conductivity, and low light transmittance, which can result in low heterojunction cell fill factor and low short circuit current, thereby affecting the final photoelectric conversion efficiency.

There is thus a need to provide a heterojunction solar cell, a shingle assembly, that at least partially addresses the above-mentioned problems.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a heterojunction solar wafer, imbricated subassembly and heterojunction solar wafer, imbricated subassembly manufacturing method, the utility model discloses the printing opacity conducting layer that sets up a plurality of light transmissivity gradual changes in the electrically conductive transparent region of heterojunction solar wafer to improve aspects such as the carrier excursion rate, light transmissivity and the electric conductivity of heterojunction solar wafer, make heterojunction solar wafer have higher photoelectric conversion rate.

According to an aspect of the present invention, there is provided a heterojunction solar cell, comprising a substrate sheet and electrodes disposed on top and bottom surfaces of the substrate sheet, the substrate sheet comprising:

a center layer;

a plurality of light-transmitting conductive layers stacked in a direction perpendicular to the center layer on top and bottom sides of the center layer, and light transmittance of each of the light-transmitting conductive layers increases in a direction from the center layer to the electrode.

In one embodiment, the central layer comprises a substrate layer and a plurality of amorphous silicon thin film layers which are stacked in a direction perpendicular to the central layer, and the plurality of amorphous silicon thin film layers are respectively positioned on the top side and the bottom side of the substrate layer. In one embodiment, the amorphous silicon thin film layer positioned on the top side of the substrate layer comprises an intrinsic amorphous silicon thin film layer and an N-type amorphous silicon thin film layer positioned on the top side of the intrinsic amorphous silicon thin film layer; the amorphous silicon thin film layer positioned at the bottom side of the substrate layer comprises an intrinsic amorphous silicon thin film layer and a P-type amorphous silicon thin film layer positioned at the bottom side of the intrinsic amorphous silicon thin film layer.

In one embodiment, the substrate layer is an N-type single crystal silicon layer.

The utility model discloses another aspect provides a stack tile subassembly, a serial communication port, stack tile subassembly by according to above-mentioned arbitrary scheme heterojunction solar wafer connect with the stack tile mode and form.

According to the utility model discloses, solar cell's electrically conductive transparent area is provided with the printing opacity conducting layer of a plurality of light transmissivity gradual changes, and such setting can improve aspects such as the carrier skew rate, light transmissivity and the electric conductivity of heterojunction solar wafer, avoids the filling factor to hang down, the emergence of the lower problem of the electric current that opens circuit, makes heterojunction solar wafer have higher photoelectric conversion rate.

Drawings

For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference should be made to the preferred embodiments illustrated in the accompanying drawings. Like reference numerals in the drawings refer to like parts. It will be appreciated by persons skilled in the art that the drawings are intended to illustrate preferred embodiments of the invention without any limiting effect on the scope of the invention, and that the various components in the drawings are not to scale.

Fig. 1 is a schematic view of a heterojunction solar cell according to a preferred embodiment of the present invention.

Detailed Description

Referring now to the drawings, specific embodiments of the present invention will be described in detail. What has been described herein is merely a preferred embodiment in accordance with the present invention, and those skilled in the art will appreciate that other ways of implementing the present invention on the basis of the preferred embodiment will also fall within the scope of the present invention.

The utility model provides a heterojunction solar wafer, shingling subassembly. Fig. 1 shows a schematic view of a heterojunction solar cell according to a preferred embodiment of the invention.

The heterojunction solar cell sheet comprises a substrate sheet having a top surface printed with a positive electrode and a bottom surface printed with a back electrode, the positive and back electrodes preferably being made of silver. The substrate sheet further comprises a plurality of battery sheet layers which are arranged in a stacked mode in the direction perpendicular to the substrate sheet, the plurality of battery sheet layers comprise a center layer and a plurality of light-transmitting conducting layers, the center layer is located at the center of all the battery sheet layers, and the light-transmitting conducting layers are arranged in a stacked mode in the direction perpendicular to the center layer on the top side and the bottom side of the center layer.

In order to make the light-transmitting conductive area of the substrate have gradually changed light-transmitting property, a plurality of materials can be selected and matched with different production processes to respectively manufacture a plurality of light-transmitting conductive layers, so that each light-transmitting conductive layer has different light-transmitting property. The respective light-transmitting conductive layers are arranged in the order of the strength of light transmission on the top side and the bottom side of the central layer such that the light transmission of the respective light-transmitting conductive layers increases in the direction from the central layer to the electrode (for example, in the direction upward and downward from the central layer as shown in fig. 1).

Taking the respective light-transmitting conductive layers on the top side of the central layer as an example, the light-transmitting conductive layer directly contacting the central layer is referred to as a first light-transmitting conductive layer, the light-transmitting conductive layer directly on the top side of the first light-transmitting conductive layer is referred to as a second light-transmitting conductive layer, and so on, and the light-transmitting conductive layer on the topmost part is, for example, the nth light-transmitting conductive layer. The positive electrode of the heterojunction solar cell is applied on the top surface of the Nth light-transmitting conductive layer. The light transmittances of the respective light-transmitting conductive layers increase in the direction from the central layer to the positive electrode, i.e., from the first light-transmitting conductive layer to the nth light-transmitting conductive layer. That is, the light transmittance of the first light-transmitting conductive layer is the worst, the light transmittance of the second light-transmitting conductive layer is stronger than that of the first light-transmitting conductive layer, the light transmittance of the third light-transmitting conductive layer is stronger than that of … …, the light transmittance of the nth light-transmitting conductive layer is stronger than that of the N-1 light-transmitting conductive layer, and the light transmittance of the nth light-transmitting conductive layer is the strongest.

The light-transmitting conductive layer on the bottom side of the central layer is similar. The first light-transmitting conductive layer and the second light-transmitting conductive layer … … are also arranged in this order in the direction from the central layer to the back electrode (for example, in the direction from the central layer downward in fig. 1), and the light transmittances from the first light-transmitting conductive layer to the nth light-transmitting conductive layer increase in this order.

Of course, since the light transmission and conductivity of the conductive material are sometimes inversely related, there is a possibility that the conductivity of each light-transmitting conductive layer tends to decrease in the direction from the central layer to the electrode. That is, the light-transmissive conductive layers at the topmost and bottommost portions of the substrate sheet may be slightly less conductive.

Preferably, the central layer in turn comprises a plurality of layers. For example, the central layer may include a substrate layer made of N-type single crystal silicon and amorphous silicon thin film layers on the top and bottom sides of the substrate layer, which in turn may include an intrinsic amorphous silicon thin film layer directly contacting the substrate layer and an N-type or P-type amorphous silicon thin film layer. In this embodiment, the top side of the intrinsic amorphous silicon thin film layer located on the top side of the substrate layer is an N-type amorphous silicon thin film layer, and the bottom side of the intrinsic amorphous silicon thin film layer located on the bottom side of the substrate layer is a P-type amorphous silicon thin film layer. The light-transmitting conducting layers are sequentially stacked on the top side of the N-type amorphous silicon thin film layer and the bottom side of the P-type amorphous silicon thin film layer in the manner described above.

The embodiment also provides a laminated assembly, which is formed by connecting the heterojunction solar cells in a laminated manner.

The present embodiments also provide methods of fabricating heterojunction solar cells and shingle assemblies. The heterojunction solar cell is manufactured by manufacturing a heterojunction solar cell whole piece and then splitting the heterojunction solar cell whole piece into a plurality of heterojunction solar cell pieces.

The step of manufacturing the heterojunction solar cell slice integral piece comprises the following steps: arranging a central layer; arranging a plurality of light-transmitting conductive layers on the top side and the bottom side of the central layer, and enabling the light-transmitting conductive layers to be stacked outwards from the central layer in a light-transmitting increasing mode; electrodes are applied on the top surface of the topmost light-transmissive conductive layer and on the bottom surface of the bottommost light-transmissive conductive layer.

Further, the step of providing a center layer comprises: setting an N-type monocrystalline silicon layer as a substrate layer; arranging an intrinsic amorphous silicon thin film layer on the top side of the substrate layer and arranging an N-type amorphous silicon thin film layer on the top side of the intrinsic amorphous silicon thin film layer; an intrinsic amorphous silicon thin film layer is arranged on the bottom side of the substrate layer, and a P-type amorphous silicon thin film layer is arranged on the bottom side of the intrinsic amorphous silicon thin film layer.

The method of manufacturing a laminated assembly provided by this embodiment includes the steps of: manufacturing a heterojunction solar cell based on the method; and sequentially connecting a plurality of heterojunction solar cells in a tiling mode.

The utility model provides a heterojunction solar wafer, imbricated subassembly and heterojunction solar wafer, imbricated subassembly's manufacturing method for the electrically conductive transparent area of the heterojunction solar wafer that obtains is provided with the printing opacity conducting layer of a plurality of light transmissivity gradual changes, such setting can improve aspects such as the carrier off-set rate, light transmissivity and the electric conductivity of heterojunction solar wafer, avoids filling factor to hang down, the emergence of the lower problem of electric current that opens circuit, makes heterojunction solar wafer have higher photoelectric conversion rate.

The foregoing description of various embodiments of the invention is provided to one of ordinary skill in the relevant art for the purpose of illustration. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. As noted above, various alternatives and modifications of the present invention will be apparent to those skilled in the art of the above teachings. Thus, while some alternative embodiments are specifically described, other embodiments will be apparent to, or relatively easily developed by, those of ordinary skill in the art. The present invention is intended to embrace all such alternatives, modifications and variances of the present invention described herein, as well as other embodiments that fall within the spirit and scope of the present invention as described above.

Claims

1. A heterojunction solar cell sheet comprising a substrate sheet and electrodes disposed on top and bottom surfaces of the substrate sheet, wherein the substrate sheet comprises:

a center layer;

2. The heterojunction solar cell of claim 1, wherein the central layer comprises a substrate layer and a plurality of amorphous silicon thin film layers stacked in a direction perpendicular to the central layer, the plurality of amorphous silicon thin film layers being respectively located on the top and bottom sides of the substrate layer.

3. The heterojunction solar cell of claim 2, wherein the amorphous silicon thin film layer on the top side of the substrate layer comprises an intrinsic amorphous silicon thin film layer and an N-type amorphous silicon thin film layer on the top side of the intrinsic amorphous silicon thin film layer; the amorphous silicon thin film layer positioned at the bottom side of the substrate layer comprises an intrinsic amorphous silicon thin film layer and a P-type amorphous silicon thin film layer positioned at the bottom side of the intrinsic amorphous silicon thin film layer.

4. The heterojunction solar cell of claim 2, wherein said substrate layer is an N-type single crystal silicon layer.

5. A stack of tiles, characterized in that the stack of tiles is formed by connecting the heterojunction solar cells of any of claims 1 to 4 in a stack.