CN210866218U

CN210866218U - Heterojunction solar cell piece, pile of tile subassembly

Info

Publication number: CN210866218U
Application number: CN201921822324.8U
Authority: CN
Inventors: 王秀鹏; 王月斌; 姚骞
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: 2020-06-26
Anticipated expiration: 2029-10-28

Abstract

The utility model relates to a heterojunction solar wafer, shingling subassembly. The heterojunction solar cell comprises a substrate sheet and electrodes arranged on the top surface and the bottom surface of the substrate sheet, the substrate sheet comprises a center layer and a plurality of amorphous silicon thin film layers and light-transmitting conductive layers which are sequentially stacked from the center layer in a direction perpendicular to the center layer on the top side and the bottom side of the center layer, and the doping concentration of each amorphous silicon thin film layer is increased progressively on the top side and the bottom side of the center layer and from the center layer. The amorphous silicon thin film region of the heterojunction solar cell is formed by a plurality of amorphous silicon thin film layers with different doping concentrations, so that the amorphous silicon thin film region with gradually changed doping concentrations is obtained, and the amorphous silicon thin film region and the light-transmitting conducting layer are small in contact resistance, high in filling factor, good in passivation effect and high in open-circuit voltage.

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 between the heterojunction 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 existing heterojunction cell structure can encounter a difficult-to-decide problem when depositing a doped amorphous silicon thin film: if the doping concentration is lower, a better passivation effect can be obtained, but the conductivity of the amorphous silicon film is poor, the contact resistance of the amorphous silicon film and the transparent conductive film is larger, and finally the filling factor of the battery is lower; if the doping concentration is higher, the conductivity of the amorphous silicon film can be improved, and the contact resistance between the amorphous silicon film and the transparent conductive film is reduced, but the passivation effect is poor, and finally the open-circuit voltage of the battery is lower.

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, shingle assembly, the utility model discloses amorphous silicon thin film region at heterojunction solar wafer is formed by the different amorphous silicon thin film layer of a plurality of doping concentration jointly to the amorphous silicon thin film region of doping concentration gradual change has been obtained, makes amorphous silicon thin film region less with the contact resistance of printing opacity conducting layer, the fill factor is higher, the passivation effect is also better, open circuit voltage is higher.

According to an aspect of the utility model, a heterojunction solar wafer is provided, heterojunction solar wafer includes the base member piece, sets up positive electrode on the top surface of base member piece and setting are in back electrode on the basal surface of base member piece, the base member piece includes the centre layer and is in the top side and the bottom side of centre layer are along the perpendicular to the direction of centre layer certainly the centre layer is started to stack gradually a plurality of amorphous silicon thin layer and the printing opacity conducting layer that set up, and, from the centre layer plays directional in the direction of positive electrode and from the centre layer plays directional in the direction of back electrode, each amorphous silicon thin layer arranges with the mode that doping concentration increases progressively.

In one embodiment, the central layer comprises a substrate layer and intrinsic amorphous silicon thin film layers disposed on top and bottom sides of the substrate layer.

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

In one embodiment, each amorphous silicon thin film layer on the top side of the central layer is an N-type amorphous silicon thin film layer, and each amorphous silicon thin film layer on the bottom side of the central layer is a P-type amorphous silicon thin film layer.

In one embodiment, the light-transmitting conductive layers 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 are both multiple, the multiple light-transmitting conductive layers have different transmittances, and the light-transmitting conductive layers are arranged in a manner of increasing transmittances in a direction from the central layer to the positive electrode and in a direction from the central layer to the back electrode.

According to the utility model discloses a another aspect provides a stack tile subassembly, stack tile subassembly by according to any one of the scheme the heterojunction solar wafer form with the mode connection of stacking tiles.

According to the utility model discloses, the doping concentration gradual change in the amorphous silicon film region of heterojunction solar wafer for the contact resistance of amorphous silicon film region and printing opacity conducting layer is less, fill factor is higher, the passivation effect is also better, open circuit voltage is higher.

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 piece comprises a plurality of cell piece layers which are stacked on one another in a direction perpendicular to the substrate piece, the cell piece layers comprise a center layer and a plurality of amorphous silicon thin film layers and a plurality of light-transmitting conducting layers, the center layer is located at the center of all the cell piece layers, and the amorphous silicon thin film layers and the light-transmitting conducting layers are stacked on the top side and the bottom side of the center layer in the direction perpendicular to the center layer.

The amorphous silicon thin film layers are arranged on the top side of the central layer, the doping concentration of each amorphous silicon thin film layer is different, and the doping concentration of each amorphous silicon thin film layer increases progressively in the direction from the central layer and towards the positive electrode. Similarly, the amorphous silicon thin film layers positioned at the bottom side of the central layer are multiple, the doping concentration of each amorphous silicon thin film layer is different, and the doping concentration of each amorphous silicon thin film layer is increased gradually in the direction from the central layer to the back electrode.

Referring to fig. 1, it can be seen that in the present embodiment, each amorphous silicon thin film layer located on the top side of the central layer is an N-type amorphous silicon thin film layer, and each amorphous silicon thin film layer located on the bottom side of the central layer is a P-type amorphous silicon thin film layer.

The first N-type amorphous silicon thin film layer and the second N-type amorphous silicon thin film layer … … are sequentially arranged on the top side of the central layer from the central layer, wherein the doping concentration of the first N-type amorphous silicon thin film layer is the lowest, the doping concentration of the second N-type amorphous silicon thin film layer is greater than that of the first N-type amorphous silicon thin film layer, and the doping concentration of the third N-type amorphous silicon thin film layer is greater than that of the second N-type amorphous silicon thin film layer, namely … …, and the doping concentration of the Nth N-type amorphous silicon thin film layer is greater than that of the N-1 th N-type amorphous silicon thin film layer.

Similarly, a first P-type amorphous silicon thin film layer and a second P-type amorphous silicon thin film layer … … are sequentially arranged on the bottom side of the central layer from the central layer, wherein the doping concentration of the first P-type amorphous silicon thin film layer is the lowest, the doping concentration of the second P-type amorphous silicon thin film layer is greater than that of the first P-type amorphous silicon thin film layer, and the doping concentration of the third P-type amorphous silicon thin film layer is greater than that of the second P-type amorphous silicon thin film layer … …, and the doping concentration of the nth P-type amorphous silicon thin film layer is greater than that of the N-1P-type amorphous silicon thin film layer.

Due to the arrangement, the amorphous silicon thin film region of the heterojunction solar cell has gradually-changed doping concentration, and the problem that the whole amorphous silicon thin film region is too high or low in doping concentration possibly caused is avoided. The arrangement ensures that the contact resistance between the amorphous silicon film region and the light-transmitting conducting layer is smaller, the filling factor is higher, and meanwhile, the passivation effect is better and the open-circuit voltage is higher.

Preferably, in order to enable the light-transmitting conductive area of the substrate sheet to have gradually changed light-transmitting properties, 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 properties. And arranging the light-transmitting conducting layers on the top side and the bottom side of the amorphous silicon thin film layer according to the light-transmitting strength sequence, so that the light-transmitting property of each light-transmitting conducting layer is increased progressively in the direction from the amorphous silicon thin film layer to the electrode.

Taking the light-transmitting conductive layers on the top sides of the amorphous silicon thin film layers as an example, the light-transmitting conductive layer directly contacting with the nth N-type amorphous silicon thin film 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 transmittance of each light-transmitting conductive layer increases progressively in the direction from the Nth N-type amorphous silicon thin film 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 amorphous silicon thin film layer is similar. The first light-transmitting conductive layer and the second light-transmitting conductive layer … … are also sequentially arranged in the direction from the Nth P-type amorphous silicon film layer to the back electrode, and the light transmittances of the first light-transmitting conductive layer to the Nth light-transmitting conductive layer are sequentially increased.

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 center layer may include a substrate layer made of N-type single crystal silicon and intrinsic amorphous silicon thin film layers on the top and bottom sides of the substrate layer.

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 amorphous silicon thin film layers on the top side and the bottom side of the central layer, and enabling the amorphous silicon thin film layers to be arranged in a stacking mode from the central layer to the outside in a mode of increasing the doping concentration, in the step, preferably applying an N-type amorphous silicon thin film layer on the top side of the central layer and applying a P-type amorphous silicon thin film layer on the bottom side of the central layer; respectively arranging light-transmitting conductive layers on the top surface of the topmost amorphous silicon thin film layer and the bottom surface of the bottommost amorphous silicon thin film layer, thereby obtaining a substrate sheet comprising a center layer, an amorphous silicon thin film layer and a light-transmitting conductive layer; electrodes are applied to the top and bottom surfaces of the base sheet.

Further, the step of providing a center layer comprises: texturing the N-type monocrystalline silicon layer and setting the N-type monocrystalline silicon layer as a substrate layer; disposing an intrinsic amorphous silicon thin film layer on a top side of the substrate layer; an intrinsic amorphous silicon thin film layer is disposed on the bottom side of the substrate 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, shingling subassembly and heterojunction solar wafer, shingling subassembly's manufacturing method for the amorphous silicon thin film region of the heterojunction solar wafer that obtains forms jointly by the different amorphous silicon thin film layer of a plurality of doping concentration, thereby obtained the amorphous silicon thin film region of doping concentration gradual change, make the contact resistance of amorphous silicon thin film region and printing opacity conducting layer less, fill factor is higher, the passivation effect is also better, open circuit voltage is higher. In addition, the conductive transparent area of the heterojunction solar cell can be provided with a plurality of light-transmitting conductive layers with gradually changed light transmission, so that the carrier offset rate, the light transmission, the conductivity and the like of the heterojunction solar cell can be improved, the problems of low filling factor and low open circuit current are avoided, and the heterojunction solar cell has high 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 piece, the heterojunction solar cell piece includes the base member piece, set up the positive electrode on the top surface of the base member piece and set up the back electrode on the bottom surface of the base member piece, characterized by that, the base member piece includes the centre layer and in the top side and bottom side of the centre layer along perpendicular to the direction of the centre layer from the centre layer a plurality of amorphous silicon thin film layers and light transmission conducting layer that set up in proper order, and, in from the direction of the centre layer pointing to the positive electrode and from the direction of the centre layer pointing to the back electrode, each amorphous silicon thin film layer arranges in the mode that the doping concentration increases progressively.

2. The heterojunction solar cell of claim 1, wherein the central layer comprises a substrate layer and intrinsic amorphous silicon thin film layers disposed on top and bottom sides of the substrate layer.

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

4. The heterojunction solar cell of claim 1, wherein each of the amorphous silicon thin film layers on the top side of the central layer is an N-type amorphous silicon thin film layer, and each of the amorphous silicon thin film layers on the bottom side of the central layer is a P-type amorphous silicon thin film layer.

5. The heterojunction solar cell of claim 4, wherein the light-transmissive conductive layers on the top side of the N-type amorphous silicon thin film layer and on the bottom side of the P-type amorphous silicon thin film layer are each a plurality of layers having different transmittances, and each of the light-transmissive conductive layers is arranged with increasing transmittances in a direction from the central layer to the positive electrode and in a direction from the central layer to the back electrode.

6. 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 5 in a stack.