CN213340395U

CN213340395U - Metal mesh grid interconnection structure

Info

Publication number: CN213340395U
Application number: CN202022651514.7U
Authority: CN
Inventors: 俞健; 白宇; 陈涛
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-06-01
Anticipated expiration: 2030-11-17

Abstract

The utility model discloses a metal mesh grid interconnection structure. Two layers of metal mesh grids are respectively adhered on the front surface TCO and the back surface TCO of a heterojunction solar cell without metal electrodes through two layers of transfer films; The poles of opposite polarities are connected between the mass junction solar cell structures through metal grids. The present application uses the solar cell metal grid interconnection structure in the heterojunction solar cell to realize interconnected packaging, so that the metal grid is directly attached to the surface of the heterojunction solar cell, avoiding the high cost of using low-temperature silver paste in the screen printing method. The problem of cost or poor conductivity when using high temperature silver paste; two layers of metal grids are respectively adhered to the heterojunction solar cells without electrodes through two layers of transfer films, as long as they can be directly attached under certain hot pressing conditions Combined on the surface of the heterojunction solar cell, such a structural design simplifies the processing process and greatly reduces the cost of the cell.

Description

Metal mesh grid interconnection structure

Technical Field

The utility model belongs to the technical field of solar cell makes, concretely relates to metal mesh grid interconnection structure.

Background

The solar cell is a new energy device which directly realizes photoelectric conversion by utilizing a photovoltaic effect. Higher conversion efficiency and lower production cost are the keys for breaking through the development bottleneck of the solar cell and developing the practical application of solar energy. The a-Si/c-Si heterojunction solar cell integrates the process advantages of the thin film cell, fully exerts the material characteristics of the crystalline silicon substrate and the amorphous silicon thin film, has the advantages of good passivation effect, simple structure, good temperature characteristic, low process temperature and the like, and becomes a hotspot for the development of high-efficiency solar cells.

After a PN junction is prepared, utilizing a photovoltaic effect to excite and separate photon-generated carriers, wherein electrons of the photon-generated carriers move to the N side, and holes of the photon-generated carriers move to the P side to form a physical positive electrode and a physical negative electrode; therefore, metal electrodes are required to be deposited on the positive and negative electrodes of the battery to collect carriers for photovoltaic power generation. Therefore, different solar cell metal grid line designs and electrode preparation modes obviously influence the transport and collection of carriers, thereby influencing the electrical property.

The screen printing technology has the advantages of simple process, large design space of printed patterns, suitability for large-scale production and the like, and becomes the preferred technology for preparing the electrodes for mass production of batteries. However, the heterojunction cell is limited by a low-temperature process, and the electrode is prepared by selecting low-temperature conductive silver paste, so that the conductivity of the electrode is poor, the contact resistance with the TCO is high, the printing plasticity of the electrode is difficult to be considered, the aspect ratio is small, and the ohmic loss of the electrode is large. The resistivity of the screen printing low-temperature silver paste is higher, which is about 3-5 times that of the high-temperature silver paste, so that more low-temperature silver paste must be deposited to improve the conductivity of the electrode in order to reduce the resistance loss of the electrode, the price of the low-temperature silver paste is high, the cost proportion of a battery manufacturing process is 30% or more, and cost reduction and efficiency improvement are urgently needed.

Therefore, it is highly desirable to develop a metal mesh interconnection structure to solve the above problems.

Disclosure of Invention

In order to solve the problem provided in the background art, the utility model provides a metal mesh grid interconnection structure.

In order to achieve the above object, the utility model provides a following technical scheme:

a metal grid interconnect structure comprising at least two heterojunction solar cell structures, the heterojunction solar cell structure comprising:

two layers of transfer films;

two layers of metal grids;

a heterojunction solar cell without an electrode; the two layers of metal grids are respectively adhered to a front electrode and a back electrode of the heterojunction solar cell without the electrodes through two layers of transfer films;

two electrodes with opposite polarities are connected between the two heterojunction solar cell structures through the metal mesh grid.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the solar cell metal mesh grid interconnection structure is applied to the heterojunction solar cell to realize silver-free interconnection packaging, so that the metal mesh grid is directly attached to the surface of the heterojunction solar cell, and the problem of high cost of low-temperature silver paste or poor conductivity when high-temperature silver paste is used in a screen printing method is avoided;

2. the two layers of metal grids are adhered to the heterojunction solar cell without the electrodes through the two layers of transfer films respectively, and can be directly attached to the surface of the heterojunction solar cell under certain hot-pressing conditions, so that the processing technology is simpler due to the structural design, and the cell cost is greatly reduced.

Drawings

FIG. 1 is a schematic diagram of a solar cell metal grid interconnection structure;

FIG. 2 is a schematic view of the composition of a wire of the present application;

FIG. 3 is a first schematic diagram of a metal grid structure according to the present application;

fig. 4 is a second schematic view of a metal mesh structure in the present application;

fig. 5 is a third schematic view of a metal mesh structure in the present application;

labeled as:

1-transferring the membrane; 2-a metal mesh grid; 201-a wire; 21-outer adhesive metal layer; 22-inner conductive metal layer; 3-heterojunction solar cell.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The utility model provides a following technical scheme:

as shown in fig. 1, a metal mesh interconnection structure includes at least two heterojunction solar cell 3 structures, and the heterojunction solar cell 3 structure includes:

two layers of transfer films 1;

two layers of metal grids 2;

a heterojunction solar cell 3 without electrodes; the two layers of metal grids 2 are respectively adhered to a front electrode and a back electrode of a heterojunction solar cell 3 without an electrode through two layers of transfer films 1; thereby realizing current conduction;

two electrodes with opposite polarities are connected between the two heterojunction solar cells 3 through the metal mesh 2.

In the embodiment, the heterojunction solar cell 3 is not provided with a metal electrode, the metal mesh 2 adhered to the transfer film 1 is distributed on the surface of the heterojunction solar cell to form an interconnection mode with a staggered anode and cathode, the metal mesh 2 and the transfer film 1 are attached to the surface of the heterojunction solar cell in the lamination process, and photo-generated carriers are collected through the metal mesh 2, so that the purpose of photoelectric conversion of the heterojunction solar cell is achieved.

In this embodiment, the metal mesh 2 adhered to the transfer film 1 is arranged on the surface of the heterojunction solar cell to form an interconnection mode with staggered positive and negative electrodes, and the metal mesh 2 and the transfer film 1 are attached to the surface of the heterojunction solar cell in the lamination process, so as to achieve the purpose of leading out the photo-generated current.

In some embodiments, the metal mesh grid 2 includes a plurality of vertical metal wires 201 and a plurality of horizontal metal wires 201, the plurality of vertical metal wires 201 are parallel to each other and are arranged at equal intervals, the plurality of horizontal metal wires 201 are parallel to each other and are arranged at equal intervals, and the plurality of vertical metal wires 201 are vertically intersected and connected with the plurality of horizontal metal wires 201.

In some embodiments, the metal grid 2 includes 2 to 6 vertical wires 201 and 36 to 100 horizontal wires 201, the 36 to 100 horizontal wires 201 are parallel to each other and are arranged at equal intervals, the 2 to 6 vertical wires 201 are parallel to each other, and the 2 to 6 vertical wires 201 are vertically intersected and connected with the 36 to 100 horizontal wires 201.

As shown in fig. 3, preferably, the metal grid 2 includes 2 vertical metal wires 201 and 36 transverse metal wires 201, the 36 transverse metal wires 201 are arranged in parallel, the 2 vertical metal wires 201 are arranged in parallel, and the 2 vertical metal wires 201 are connected with the 36 transverse metal wires 201 in a vertical intersecting manner. Similar to form H. Here, in the metal wire 201, copper is used as an inner conductive metal layer, and indium is used as an outer adhesive metal layer.

In some embodiments, the metal grid 2 includes 36 to 140 vertical metal wires 201 and 36 to 140 transverse metal wires 201, the 36 to 140 vertical metal wires 201 are arranged in parallel, the 36 to 140 transverse metal wires 201 are arranged in parallel, and the 36 to 140 vertical metal wires 201 are vertically intersected and connected with the 36 to 140 transverse metal wires 201.

As shown in fig. 4, preferably, the metal grid 2 includes 36 vertical metal wires 201 and 36 transverse metal wires 201, the 36 vertical metal wires 201 are arranged in parallel, the 36 transverse metal wires 201 are arranged in parallel, and the 36 vertical metal wires 201 are vertically intersected and connected with the 36 transverse metal wires 201. Similar to the grid type. In the wire 201, copper is preferably used for the inner conductive metal layer, and tin is preferably used for the outer adhesive metal layer. In the present embodiment, with such a shape of the metal mesh 2, the distance between the metal wires 201 is smaller, and the carrier transport distance is also smaller, so that the carrier collection probability is greater, and the conductivity of the metal mesh 2 is higher.

As shown in fig. 5, in some embodiments, the metal mesh grid 2 includes a plurality of regular hexagonal wire 201 structures, and the plurality of regular hexagonal wire 201 structures constitute a honeycomb structure.

In some embodiments, the metal mesh grid 2 comprises a 150 to 1000 regular hexagonal wire 201 structure.

In this embodiment, the honeycomb-shaped metal grid 2 has a good balance between electrical performance and optical loss.

In the application, the shading loss and the electrical loss can be effectively reduced by the H-shaped, grid-shaped and honeycomb-shaped innovative grid pattern design, the transmission distance of carriers is reduced, the collection probability is improved, the current distributed to each grid line is reduced, the ohmic loss of the electrode is obviously reduced, and the conversion efficiency of the battery is improved.

As shown in fig. 2, the wire 201 includes an outer adhesion metal layer 21 and an inner conductive metal layer 22, and the outer adhesion metal layer 21 is disposed to cover the inner conductive metal layer 22.

In some embodiments, the inner conductive metal layer 22 is made of any one of aluminum, copper, nickel, tin, silver, aluminum alloy, copper alloy, nickel alloy, tin alloy, and silver alloy; the bonding metal layer is made of any one of indium, tin, bismuth, silver, indium alloy, tin alloy, bismuth alloy and silver alloy.

In some embodiments, the size of the metal grid does not exceed the size of the solar cell, and the metal wire 201 has a diameter of 1-100 microns, wherein the inner conductive metal layer 22 has a diameter of 1-90 microns and the outer bonding metal has a thickness of 1-10 microns.

In some embodiments, the transfer film 1 is generally an organic high molecular polymer, opaque and non-tacky at room temperature; when the heating temperature exceeds 110 ℃, the film is converted into a transparent film and has viscosity, and can be adhered to the surface of the heterojunction solar cell to form good adhesion. The transfer film 1 is a poly-1-butylene film or an EVA hot melt adhesive film or a polyacrylate adhesive film.

The preparation method of the solar cell metal mesh grid interconnection structure comprises the following steps:

manufacturing a heterojunction solar cell without an electrode;

selecting a metal mesh grid material, designing and printing a graph of the metal mesh grid by laser;

bonding the transfer film on the designed metal mesh grid in a hot-pressing state;

connecting a front electrode of the heterojunction solar cell with a back electrode of another heterojunction solar cell by adopting a metal mesh grid bonded with a transfer film;

and packaging the connected heterojunction solar cell at the temperature of 130-150 ℃.

The preparation method of the metal mesh grid can also be wire drawing, rolling, electroforming, electroplating and the like.

The heterojunction solar cell is manufactured by the following steps:

the surface texturing of n-type monocrystalline silicon wafers in an alkaline solution to produce random pyramids, the thickness of the wafers being 240 μm.

And cleaning in a diluted hydrofluoric acid solution to remove the natural silicon oxide.

Intrinsic amorphous silicon (a-Si: H (i)) thin films are deposited on both sides of a silicon wafer by Plasma Enhanced Chemical Vapor Deposition (PECVD).

P-type and n-type amorphous silicon films (a-Si: H (p) and a-Si: H (n), respectively) are then deposited to create hole and electron selective contacts on the front and back surfaces, respectively. The thickness of the amorphous silicon layer is about 10 nm.

And respectively depositing a layer of transparent conductive film on the p-type surface and the n-type surface.

Wherein, the transparent conductive film is made of ITO, IZO, AZO and graphene, and has a thickness of 0-500 nm. The transparent conductive layer is manufactured by magnetron sputtering, Reactive Plasma Deposition (RPD) or chemical vapor deposition (MOCVD), wherein the magnetron sputtering can be radio frequency magnetron sputtering (RF) or direct current magnetron sputtering (DC), and the chemical vapor deposition can be Plasma Enhanced Chemical Vapor Deposition (PECVD), Atomic Layer Deposition (ALD), Low Pressure Chemical Vapor Deposition (LPCVD) or Metal Organic Chemical Vapor Deposition (MOCVD).

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A metal grid interconnection structure, characterized in that it comprises at least two heterojunction solar cell structures, the heterojunction solar cell structures comprising:

Two-layer transfer film;

Two-layer metal grid;

Heterojunction solar cell without electrodes; two layers of metal grids are respectively adhered to the front electrode and the back electrode of the heterojunction solar cell without electrodes through two layers of transfer films;

The opposite polarities are connected between the two heterojunction solar cell structures through a metal grid.

2. A metal mesh grid interconnection structure according to claim 1, wherein the metal mesh grid comprises a plurality of vertical metal wires and a plurality of horizontal metal wires, and the plurality of vertical metal wires are arranged parallel to each other and at equal intervals , a plurality of horizontal metal wires are arranged in parallel with each other and at equal intervals, and a plurality of vertical metal wires are vertically intersected and connected with a plurality of horizontal metal wires.

3. A metal grid interconnection structure according to claim 2, wherein the metal grid comprises 2-6 vertical metal wires and 36-100 horizontal metal wires, and the 36-100 horizontal metal wires are mutually Parallel and equally spaced, 2-6 vertical metal wires are arranged parallel to each other, and 2-6 vertical metal wires are vertically intersected with 36-100 horizontal metal wires.

4. A metal mesh grid interconnection structure according to claim 2, wherein the metal mesh grid comprises 36-140 vertical metal wires and 36-140 horizontal metal wires, and 36-140 vertical metal wires They are arranged parallel to each other, 36-140 horizontal metal wires are arranged parallel to each other, and 36-140 vertical metal wires are vertically intersected with 36-140 horizontal metal wires.

5 . The metal mesh grid interconnection structure according to claim 1 , wherein the metal mesh grid comprises a plurality of regular hexagonal metal wire structures, and the multiple regular hexagonal metal wire structures form a honeycomb structure. 6 .

6 . The metal grid interconnection structure according to claim 5 , wherein the metal grid comprises 150 to 1000 regular hexagonal metal wire structures. 7 .

7. The metal grid interconnection structure according to any one of claims 2-6, wherein the metal wire comprises an outer adhesive metal layer and an inner conductive metal layer, and the outer adhesive metal layer covers The inner conductive metal layer is provided.

8. A metal grid interconnection structure according to claim 7, wherein the inner conductive metal layer is aluminum, copper, nickel, tin, silver, aluminum alloy, copper alloy, nickel alloy, tin alloy, silver The adhesive metal layer is made of any one of indium, tin, bismuth, silver, indium alloy, tin alloy, bismuth alloy, and silver alloy.

9. A metal grid interconnection structure according to claim 7, wherein the diameter of the metal wire is 1-100 microns, the diameter of the inner conductive metal layer is 1-90 microns, and the thickness of the outer layer of bonding metal is 1-100 microns. 1-10 microns.

10 . The metal grid interconnection structure according to claim 1 , wherein the transfer film is a poly-1-butene film, an EVA hot-melt adhesive film or a polyacrylate adhesive film. 11 .