CN117476807B

CN117476807B - Electrode and preparation method thereof, solar cell

Info

Publication number: CN117476807B
Application number: CN202311464053.4A
Authority: CN
Inventors: 施少雄; 黄远提; 杨应喜
Original assignee: Guangdong Shengyang Huachuang Technology Co ltd
Current assignee: Guangdong Shengyang Huachuang Technology Co ltd
Priority date: 2023-11-06
Filing date: 2023-11-06
Publication date: 2025-03-07
Anticipated expiration: 2043-11-06
Also published as: CN117476807A

Abstract

The present application relates to an electrode and a preparation method thereof, and a solar cell. The preparation method of the electrode of the present application includes: providing a substrate; preparing a first metal layer on the surface of the substrate, the material of the first metal layer includes copper, and the preparation method of the first metal layer includes physical vapor deposition; preparing a second metal layer on the surface of the first metal layer, the material of the second metal layer includes at least one of titanium, titanium alloy, nickel, nickel alloy, chromium, chromium alloy, silver, silver alloy, molybdenum, molybdenum alloy, manganese and manganese alloy; preparing a third metal layer on the surface of the second metal layer, the material of the third metal layer includes copper, and the preparation method of the third metal layer includes physical vapor deposition; preparing a fourth metal layer on the surface of the third metal layer, the material of the fourth metal layer includes copper, and the preparation method of the fourth metal layer includes electroplating.

Description

Electrode, preparation method thereof and solar cell

Technical Field

The application relates to the technical field of photovoltaics, in particular to an electrode, a preparation method thereof and a solar cell.

Background

The preparation of silver electrodes by screen printing silver paste is the main stream mode for preparing solar cell electrodes at present, but low-temperature silver paste is expensive, and the cost reduction of the silicon heterojunction solar cell is limited. Electroplated copper electrodes are one of the viable alternatives to silver electrodes to reduce the cost of solar cells.

The traditional copper electroplating electrode is prepared by firstly depositing a copper seed layer on a transparent metal oxide film through physical vapor deposition, coating a photosensitive film on the copper seed layer, and carrying out copper electroplating after forming patterns through ultraviolet exposure and development. However, the photosensitive film on the electroplated copper surface in the copper electrode prepared by the method is easy to remain, so that holes are easy to generate between the electroplated copper layer and the copper seed crystal layer, and the contact resistance is high, so that the conversion efficiency of the solar cell is low.

Disclosure of Invention

Based on this, it is necessary to provide an electrode, a method for producing the same, and a solar cell. The bonding force between each layer of the electrode prepared by the preparation method of the electrode is high, so that the contact resistance between the electrode and the solar cell can be effectively reduced, and the conversion efficiency of the solar cell is further improved.

In a first aspect, the present application provides a method for preparing an electrode, comprising:

Providing a substrate;

Preparing a first metal layer on the surface of the substrate, wherein the material of the first metal layer comprises copper, and the preparation method of the first metal layer comprises physical vapor deposition;

preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy;

preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer comprises copper, and the preparation method of the third metal layer comprises physical vapor deposition;

and preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer comprises copper, and the preparation method of the fourth metal layer comprises electroplating.

In some embodiments, the thickness of the first metal layer is 10 nm-200 nm.

In some embodiments, the thickness of the second metal layer is 10 nm-200 nm.

In some embodiments, the thickness of the third metal layer is 10 nm-200 nm.

In some embodiments, the fourth metal layer has a thickness of 5 μm to 20 μm.

In some embodiments, before preparing the fourth metal layer on the surface of the third metal layer, the method further comprises:

and carrying out first acid washing on the third metal layer to remove oxide on the surface of the third metal layer.

In some embodiments, after preparing the fourth metal layer on the surface of the third metal layer, further comprising:

Preparing a mask layer on the surface of the fourth metal layer;

performing first etching on the fourth metal layer and the third metal layer exposed out of the mask layer by using a first etching solution;

Performing second etching on the second metal layer exposed out of the mask layer by using a second etching solution;

Performing third etching on the first metal layer exposed out of the mask layer by using a third etching solution;

and removing the mask layer.

In some embodiments, the first etching solution comprises an acidic etching solution or an alkaline etching solution, the acidic etching solution comprises copper chloride with a mass volume concentration of 120 g/L-180 g/L and hydrochloric acid with a mass volume concentration of 30 g/L-70 g/L, and the alkaline etching solution comprises copper chloride with a mass volume concentration of 120 g/L-180 g/L and ammonia water with a mass volume concentration of 50 g/L-100 g/L.

In some embodiments, the second etching solution includes 5% -15% of hydrogen peroxide and 1% -5% of phosphoric acid by mass, and the pH of the second etching solution is 1-3.

In some embodiments, the third etching solution includes 0.1% -0.5% sulfuric acid and 1% -3% sodium persulfate by mass, and the pH range of the third etching solution is 1-3.

In some embodiments, the temperature of the first etch is 30 ℃ to 50 ℃.

In some embodiments, the first etching time is 60s to 120s.

In some embodiments, the temperature of the second etch is 30 ℃ to 50 ℃.

In some embodiments, the second etching time is 10s to 60s.

In some embodiments, the temperature of the third etch is 20 ℃ to 30 ℃.

In some embodiments, the third etching time is 10s to 60s.

In some embodiments, before preparing the mask layer on the surface of the fourth metal layer, the method further includes:

And carrying out second acid washing on the fourth metal layer to remove oxide on the surface of the fourth metal layer.

In some embodiments, removing the mask layer further comprises:

and preparing a fifth metal layer on the surface of the fourth metal layer, wherein the material of the fifth metal layer comprises at least one of silver, silver alloy, tin and tin alloy.

In some embodiments, the preparing a fifth metal layer on the surface of the fourth metal layer further comprises:

And carrying out annealing treatment on the electrode.

In some embodiments, the temperature of the annealing process is 100 ℃ to 150 ℃.

In some embodiments, the heat preservation time of the annealing treatment is 0.5 h-3 h.

In a second aspect, the present application provides an electrode prepared by the method for preparing an electrode according to any one of the above, comprising:

The first metal layer, the second metal layer, the third metal layer and the fourth metal layer are sequentially stacked;

The material of the first metal layer comprises copper, the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy, the material of the third metal layer comprises copper, and the material of the fourth metal layer comprises copper.

In some embodiments, the electrode includes a fifth metal layer on a surface of the fourth metal layer, the material of the fifth metal layer including at least one of silver, silver alloy, tin, and tin alloy.

In a third aspect, the application provides a solar cell comprising an electrode prepared by the method for preparing an electrode according to any one of the above, or an electrode according to any one of the above.

In the method for preparing the electrode, a first metal layer is prepared on the surface of the substrate, the material of the first metal layer comprises copper, the method for preparing the first metal layer comprises physical vapor deposition, and the first metal layer is used as a seed crystal layer. And preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy, and the second metal layer is used as a protective layer of the first metal layer, so that the first metal layer can be prevented from being damaged in subsequent etching, and the bonding effect between the second metal layer and the first metal layer is good. And preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer comprises copper, the preparation method of the third metal layer comprises physical vapor deposition, the third metal layer is used as a protective layer of the second metal layer, the surface of the second metal layer can be prevented from being oxidized, and the combination effect between the third metal layer and the second metal layer is good. And preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer comprises copper, the preparation method of the fourth metal layer comprises electroplating, the fourth metal layer is used as a thickened copper metal layer and is used as a current conducting layer, the thicker copper metal layer can be prepared in a shorter time through electroplating, and the combination effect between the fourth metal layer and the third metal layer is better. The preparation method of the electrode avoids directly coating the photosensitive film on the copper seed crystal layer, can reduce the contact resistance caused by the occurrence of holes between the electroplated copper and the copper seed crystal layer due to the residue of the photosensitive film, and simultaneously has higher bonding force between the layers of the electrode prepared by the preparation method of the electrode, can effectively reduce the contact resistance between the electrode and the solar cell, and further improves the conversion efficiency of the solar cell.

Drawings

FIG. 1 is a schematic flow chart of a method for manufacturing an electrode according to an embodiment of the application;

Fig. 2 is a flow chart of a method for manufacturing an electrode according to another embodiment of the application.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second" may include at least one such feature, either explicitly or implicitly. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, mechanically connected, electrically connected, directly connected, indirectly connected through an intervening medium, or in communication between two elements or in an interaction relationship between two elements, unless otherwise explicitly specified. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

Referring to fig. 1, an embodiment of the present application provides a method for preparing an electrode, including:

s110, providing a substrate.

And S120, preparing a first metal layer on the surface of the substrate, wherein the material of the first metal layer comprises copper, and the preparation method of the first metal layer comprises physical vapor deposition.

And S130, preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy.

And S140, preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer comprises copper, and the preparation method of the third metal layer comprises physical vapor deposition.

And S150, preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer comprises copper, and the preparation method of the fourth metal layer comprises electroplating.

In the method for preparing the electrode, a first metal layer is prepared on the surface of the substrate, the material of the first metal layer comprises copper, the method for preparing the first metal layer comprises physical vapor deposition, and the first metal layer is used as a seed crystal layer. And preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy, and the second metal layer is used as a protective layer of the first metal layer, so that the first metal layer can be prevented from being damaged in subsequent etching, and the bonding effect between the second metal layer and the first metal layer is good. And preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer comprises copper, the preparation method of the third metal layer comprises physical vapor deposition, the third metal layer is used as a protective layer of the second metal layer, the surface of the second metal layer can be prevented from being oxidized, and the combination effect between the third metal layer and the second metal layer is good. And preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer comprises copper, the preparation method of the fourth metal layer comprises electroplating, the fourth metal layer is used as a thickened copper metal layer and is used as a current conducting layer, the thicker copper metal layer can be prepared in a shorter time through electroplating, and the combination effect between the fourth metal layer and the third metal layer is better. The preparation method of the electrode avoids directly coating the photosensitive film on the copper seed crystal layer, can reduce poor contact caused by holes generated between electroplated copper and the copper seed crystal layer, and meanwhile, the bonding force between the layers of the electrode prepared by the preparation method of the electrode is higher, so that the contact resistance between the electrode and a solar cell can be effectively reduced, and the conversion efficiency of the solar cell is further improved.

In one of the embodiments, the substrate is a solar cell preform. The solar cell preform includes a silicon substrate having a first surface and a second surface disposed opposite to each other, an n-type intrinsic amorphous silicon layer, an n-type doped layer, and a first transparent conductive layer disposed on the first surface, and a p-type intrinsic amorphous silicon layer, a p-type doped layer, and a second transparent conductive layer disposed on the second surface, which are sequentially stacked. It can be understood that the method for preparing the electrode in this embodiment is to prepare the electrode in the first transparent conductive layer and/or the second transparent conductive layer.

In some embodiments, the method of preparing the second metal layer includes physical vapor deposition and/or chemical deposition.

In some embodiments, pre-cleaning the solar cell preform further comprises, prior to preparing the first metal layer on the surface of the substrate. The pre-cleaning comprises the step of carrying out oil removal treatment on the solar cell preform by using an oil removal solution, wherein the oil removal treatment time is 10-200 s, and the temperature is 20-40 ℃. And (3) washing the deoiled solar cell preform at least twice, wherein the washing temperature is 20-40 ℃, the washing time is 1 min-3 min, and the washing is deionized water. And drying the washed solar cell preform at 100-200 ℃ for 5-20 min.

In some embodiments, the first metal layer has a thickness of 10nm to 200nm. When the thickness of the first metal layer is too small, the resistance value is too large, and when the thickness of the first metal layer is too large, the preparation cost is high. Optionally, the thickness of the first metal layer is 10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm or 200nm.

In some embodiments, the second metal layer has a thickness of 10nm to 200nm. When the thickness of the second metal layer is too small, the resistance value is too large, and when the thickness of the second metal layer is too large, the preparation cost is high. Optionally, the thickness of the second metal layer is 10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm or 200nm.

In some embodiments, the thickness of the third metal layer is 10nm to 200nm. When the thickness of the third metal layer is too small, the resistance value is too large, and when the thickness of the third metal layer is too large, the preparation cost is high. Optionally, the thickness of the third metal layer is 10nm、20nm、30nm、40nm、50nm、60nm、70nm、80nm、90nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm or 200nm.

In some embodiments, the fourth metal layer has a thickness of 5 μm to 20 μm. In the thickness range of the fourth metal layer, the conductive effect of the fourth metal layer is good. Optionally, the thickness of the fourth metal layer is 5μm、5.5μm、6μm、6.5μm、7μm、7.5μm、8μm、8.5μm、9μm、9.5μm、10μm、10.5μm、11μm、11.5μm、12μm、12.5μm、13μm、13.5μm、14μm、14.5μm、15μm、15.5μm、16μm、16.5μm、17μm、17.5μm、18μm、18.5μm、19μm、19.5μm or 20 μm.

In some embodiments, preparing the fourth metal layer on the surface of the third metal layer includes preparing the fourth metal layer using copper plating.

In some embodiments, the copper plating solution includes 50g/L to 200g/L copper sulfate, 100g/L to 200g/L sulfuric acid, and 30ppm to 100ppm chloride ions.

In some embodiments, prior to preparing the fourth metal layer on the surface of the third metal layer, the method further comprises a first acid washing the third metal layer to remove oxides from the surface of the third metal layer.

The oxide on the surface of the third metal layer is removed through the first acid washing, the third metal layer is activated, and the binding force between the fourth metal layer and the third metal layer can be increased.

In some embodiments, the first pickling uses a first pickling solution comprising at least one of sulfuric acid, hydrochloric acid.

In some embodiments, the mass percentage of the solute in the first pickling solution is 2% -10%. Alternatively, the mass percent of solute in the first pickling solution is 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

In some embodiments, the first acid wash is for 10s to 60s. Alternatively, the first acid wash is for a time of 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s or 60s.

In some embodiments, the temperature of the first acid wash is 20 ℃ to 30 ℃. Alternatively, the temperature of the first acid wash is 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃.

In some embodiments, the first acid washing is performed by immersing the substrate after the third metal layer is prepared in a first acid washing solution.

In some embodiments, the method further comprises preparing a mask layer on the surface of the fourth metal layer after preparing the fourth metal layer on the surface of the third metal layer, performing a first etching on the fourth metal layer and the third metal layer exposed on the mask layer by using a first etching solution, performing a second etching on the second metal layer exposed on the mask layer by using a second etching solution, performing a third etching on the first metal layer exposed on the mask layer by using a third etching solution, and removing the mask layer.

It will be appreciated that the masking layer comprises a photoresist film, and that patterning of the electrodes can be achieved by the above steps. When the first etching is performed, the second metal layer can protect the first metal layer from damage, and when the second etching is performed, a selective etching liquid which only etches the second metal layer can be used for preventing the first metal layer from damage and then etching the first metal layer.

Alternatively, the copper chloride has a mass volume concentration of 120g/L, 125g/L, 130g/L, 135g/L, 140g/L, 145g/L, 150g/L, 155g/L, 160g/L, 165g/L, 170g/L, 175g/L, or 180g/L.

Alternatively, the hydrochloric acid has a mass volume concentration of 30g/L, 35g/L, 40g/L, 45g/L, 50g/L, 55g/L, 60g/L, 65g/L, or 70g/L.

Alternatively, the ammonia may have a mass-to-volume concentration of 50g/L, 55g/L, 60g/L, 65g/L, 70g/L, 75g/L, 80g/L, 85g/L, 90g/L, or 100g/L.

In some embodiments, the second etching solution includes 5% -15% hydrogen peroxide and 1% -5% phosphoric acid by mass, and the pH of the second etching solution is 1-3.

In some embodiments, the temperature of the first etch is 30 ℃ to 50 ℃. Optionally, the temperature of the first etch is 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 46 ℃, 48 ℃, or 50 ℃.

In some embodiments, the first etch time is 60s to 120s. Optionally, the first etching time is 60s, 65s, 70s, 75s, 80s, 85s, 90s, 95s, 100s, 105s, 110s, 115s or 120s.

In some embodiments, the temperature of the second etch is 30 ℃ to 50 ℃. Optionally, the temperature of the second etch is 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 46 ℃, 48 ℃, or 50 ℃.

In some embodiments, the second etch time is 10s to 60s. Optionally, the second etching time is 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s or 60s.

In some embodiments, the temperature of the third etch is 20 ℃ to 30 ℃. Optionally, the temperature of the third etch is 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃, or 30 ℃.

In some embodiments, the third etch time is 10s to 60s. Optionally, the third etching time is 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s or 60s.

In some embodiments, preparing the mask layer on the surface of the fourth metal layer further comprises performing a second acid washing on the fourth metal layer to remove oxide on the surface of the fourth metal layer.

The oxide on the surface of the fourth metal layer is removed through the second acid washing, so that the binding force between the fourth metal layer and the mask layer can be enhanced.

In some embodiments, the second pickling uses a second pickling solution comprising at least one of sulfuric acid, hydrochloric acid.

In some embodiments, the mass percentage of the solute in the second pickling solution is 2% -10%. Alternatively, the mass percent of solute in the second pickling solution is 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

In some embodiments, the second acid wash is for 10s to 60s. Optionally, the second acid wash is for 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s or 60s.

In some embodiments, the second acid wash is at a temperature of 20 ℃ to 30 ℃. Alternatively, the second acid wash is at a temperature of 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃, or 30 ℃.

In some embodiments, the second pickling is performed by immersing the substrate after the fourth metal layer is prepared in a second pickling solution.

In some embodiments, removing the masking layer includes alkali washing the masking layer with an alkali wash, the solute of the alkali wash including at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

In some embodiments, the alkaline wash solution comprises 10% -20% solute by mass. Alternatively, the alkaline wash has a solute mass percent of 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%.

In some embodiments, the alkaline wash time is 20s to 60s. Alternatively, the alkaline wash time is 20s, 25s, 30s, 35s, 40s, 45s, 50s or 60s.

In some embodiments, the temperature of the caustic wash is 30 ℃ to 50 ℃. Alternatively, the temperature of the caustic wash is 30 ℃, 32 ℃, 34 ℃, 36 ℃, 38 ℃, 40 ℃, 42 ℃, 44 ℃, 46 ℃, 48 ℃, or 50 ℃.

In some embodiments, removing the mask layer is removing the mask layer by immersing the third etched mask layer in an alkaline cleaning solution.

In some embodiments, removing the mask layer further includes preparing a fifth metal layer on a surface of the fourth metal layer, the fifth metal layer comprising a material including at least one of silver, a silver alloy, tin, and a tin alloy. The fifth metal layer is used as a welding layer and a protective layer for welding between different electrodes and protecting each metal layer below.

In some embodiments, the method of preparing the fifth metal layer includes chemical deposition. The fifth metal layer is prepared by chemical deposition, so that the whole device can be directly subjected to chemical deposition, and the fifth metal layer is only deposited on the surface of the fourth metal layer.

In some embodiments, the method of preparing the fifth metal layer includes preparing the fifth metal layer using an electroless tin plating solution.

In some embodiments, the electroless tin plating solution includes a tin plating additive and 10g/L to 30g/L tin sulfate.

In some embodiments, the method of preparing the fifth metal layer includes preparing the fifth metal layer using a electroless silver plating solution.

In some embodiments, the electroless silver plating solution includes a silver plating additive and 10g/L to 40g/L silver nitrate.

In some embodiments, the fifth metal layer has a thickness of 0.5 μm to 1 μm. Alternatively, the fifth metal layer has a thickness of 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm.

In some embodiments, annealing the electrode is further included after preparing the fifth metal layer on the surface of the fourth metal layer. The electrode is annealed, so that the binding force between layers can be further improved, and the interface contact of the layers is good.

In some embodiments, the temperature of the annealing process is 100 ℃ to 150 ℃. Alternatively, the temperature of the annealing treatment is 100 ℃, 105 ℃, 110 ℃, 115 ℃,120 ℃, 125 ℃, 130 ℃, 135 ℃,140 ℃, or 150 ℃.

In some embodiments, the annealing process is performed for a holding time of 0.5h to 3h. Optionally, the incubation time of the annealing treatment is 0.5h, 1h, 1.5h, 2h, 2.5h or 3h.

Referring to fig. 2, in some embodiments, a method of preparing an electrode includes:

S210, providing a substrate.

S220, preparing a first metal layer on the surface of the substrate, wherein the material of the first metal layer comprises copper, and the preparation method of the first metal layer comprises physical vapor deposition.

And S230, preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy, and the preparation method of the second metal layer comprises physical vapor deposition or chemical deposition.

S240, preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer comprises copper, and the preparation method of the third metal layer comprises physical vapor deposition.

And S250, carrying out first acid washing on the third metal layer to remove oxide on the surface of the third metal layer.

And S260, preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer comprises copper, and the preparation method of the fourth metal layer comprises electroplating.

And S270, performing second acid washing on the fourth metal layer to remove oxide on the surface of the fourth metal layer.

S280, preparing a mask layer on the surface of the fourth metal layer.

And S290, performing first etching on the fourth metal layer and the third metal layer exposed out of the mask layer by using the first etching solution.

And S300, performing second etching on the second metal layer exposed out of the mask layer by using a second etching solution.

And S310, performing third etching on the first metal layer exposed out of the mask layer by using a third etching solution.

S320, removing the mask layer.

And S330, preparing a fifth metal layer on the surface of the fourth metal layer, wherein the material of the fifth metal layer comprises at least one of silver, silver alloy, tin and tin alloy.

And S340, annealing the electrode.

The electrode is prepared by the preparation method of any one of the above, and comprises a first metal layer, a second metal layer, a third metal layer and a fourth metal layer which are sequentially stacked, wherein the material of the first metal layer comprises copper, the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel alloy, chromium alloy, silver alloy, molybdenum alloy, manganese and manganese alloy, the material of the third metal layer comprises copper, and the material of the fourth metal layer comprises copper.

In some embodiments, the electrode includes a fifth metal layer on a surface of the fourth metal layer, the material of the fifth metal layer including at least one of silver, a silver alloy, tin, and a tin alloy.

A further embodiment of the application provides a solar cell comprising an electrode prepared by the method of preparing an electrode of any one of the above, or an electrode of any one of the above.

In some embodiments, a solar cell includes a silicon substrate having a first surface and a second surface disposed opposite to each other, an n-type intrinsic amorphous silicon layer, an n-type doped layer, a first transparent conductive layer, and a first electrode disposed on the first surface are sequentially stacked, a p-type intrinsic amorphous silicon layer, a p-type doped layer, a second transparent conductive layer, and a second electrode disposed on the second surface are sequentially stacked, and each of the first electrode and the second electrode is independently selected from an electrode prepared by the method of preparing an electrode of any one of the above or an electrode of any one of the above.

The following are specific examples

Example 1

Preparation of an electrode:

(1) And (3) placing the pre-cleaned solar cell preform in a first magnetron sputtering chamber, preparing a first metal layer on the surface of the transparent conductive layer by magnetron sputtering, wherein the first metal layer is a seed crystal copper layer, the magnetron sputtering power is 150W, the deposition rate is 0.5nm/s, the deposition time is 20s, and the thickness of the first metal layer is 10nm.

(2) Transferring the solar cell processed in the step (1) into a magnetron sputtering second chamber, and preparing a second metal layer on the surface of the first metal layer by magnetron sputtering, wherein the second metal layer is a titanium layer, the magnetron sputtering power is 150W, the deposition rate is 0.5nm/s, the deposition time is 20s, and the deposition thickness is 10nm.

(3) Transferring the solar cell processed in the step (2) into a third magnetron sputtering chamber, and preparing a third metal layer on the surface of the second metal layer by magnetron sputtering, wherein the third metal layer is a copper layer, the magnetron sputtering power is 150W, the deposition rate is 0.5nm/s, the deposition time is 20s, and the deposition thickness is 10nm.

(4) And (3) after the solar cell processed in the step (3) is subjected to first acid washing, the solar cell is placed into a copper plating bath solution for electroplating thickening to prepare a fourth metal layer, the fourth metal layer is a copper layer, and the thickness of the fourth metal layer is 5 mu m.

(5) And (3) forming a mask layer with an electrode pattern on the surface of the fourth metal layer after the solar cell processed in the step (4) is subjected to second acid washing, wherein the mask layer is coated in an ink-jet printing mode.

(6) And (3) after curing the solar cell processed in the step (5), placing the solar cell into an acid etching solution, and performing first etching on the fourth metal layer and the third metal layer exposed out of the mask layer, wherein the etching temperature is 30-50 ℃ and the etching time is 60-120 s.

(7) And (3) washing the solar cell processed in the step (6), then placing the solar cell into a second etching solution, and performing second etching on the second metal layer exposed out of the mask layer, wherein the etching temperature is 30-50 ℃ and the etching time is 10-60 s.

(8) And (3) washing the solar cell processed in the step (7) with water, then placing the solar cell into a third etching solution, and performing third etching on the first metal layer exposed out of the mask layer, wherein the etching temperature is 20-30 ℃ and the etching time is 10-60 s.

(9) And (3) placing the solar cell processed in the step (8) into alkaline washing liquid, and removing the mask layer, wherein the alkaline washing temperature is 30-50 ℃ and the time is 20-60 s.

(10) And (3) washing the solar cell processed in the step (9), and then placing the solar cell into an electroless tin plating solution to prepare a fifth metal layer, wherein the fifth metal layer is a tin layer, and the thickness of the fifth metal layer is 0.5 mu m.

(11) And (3) washing the solar cell processed in the step (10), and then placing the solar cell into an oven for annealing treatment, wherein the temperature of the annealing treatment is 100-150 ℃, and the heat preservation time is 0.5-3 h.

Example 2

Example 2 was substantially the same as the electrode preparation method in example 1, except that the first etching was performed on the fourth metal layer and the third metal layer exposed to the mask layer in the alkaline etching solution used in step (6).

Example 3

Example 3 was substantially the same as the electrode preparation method of example 1, except that the second metal layer in step (2) was a nickel layer.

Example 4

Example 4 was substantially the same as the electrode preparation method in example 1, except that the deposition time in step (1) was 200s, the thickness of the first metal layer was 100nm, the deposition time in step (2) was 200s, the deposition thickness was 100nm, the deposition time in step (3) was 200s, the deposition thickness was 100nm, the thickness of the fourth metal layer in step (4) was 12 μm, and the thickness of the fifth metal layer in step (10) was 0.7 μm.

Example 5

Example 5 is substantially the same as the electrode preparation method in example, except that the deposition time in step (1) is 400s, the thickness of the first metal layer is 200nm, the deposition time in step (2) is 400s, the deposition thickness is 200nm, the deposition time in step (3) is 400s, the deposition thickness is 200nm, the thickness of the fourth metal layer in step (4) is 20 μm, and the thickness of the fifth metal layer in step (10) is1 μm.

Comparative example 1

Comparative example 1 differs from example 1 only in that the preparation of the second metal layer and the third metal layer is not performed, and the fourth metal layer is directly prepared on the surface of the first metal layer.

Comparative example 2

Comparative example 2 differs from example 1 only in that the preparation of the third metal layer is not performed, and the fourth metal layer is directly prepared on the surface of the second metal layer.

Comparative example 3

The electrode in comparative example 3 was prepared by a conventional method for preparing a copper electrode by preparing a first metal layer (copper seed layer), masking layer-electroplating a fourth metal layer (copper thickening layer), preparing a fifth metal layer (tin layer), removing the masking layer-etching the first metal layer on the surface of the battery cell.

Comparative example 4

The electrode in comparative example 4 was prepared by screen printing a low temperature silver paste to prepare a silver electrode having a thickness of 10 μm to 20 μm.

The solar cells after electrode preparation in examples 1 to 5 and comparative examples 1 to 4 were subjected to photoelectric conversion efficiency and binding force test, respectively. The binding force test adopts a tensile force test method (GB/T29195-2012). The test results are shown in table 1 below:

TABLE 1

In embodiments 1 to 5, the electrode is prepared by using the preparation method of the electrode according to the present embodiment, and in the case of using the copper electrode, the second metal layer protects the first metal layer, and the third metal layer protects the second metal layer, so that a better bonding effect between the layers can be achieved, a higher photoelectric conversion efficiency of the solar cell is achieved, and a photoelectric conversion efficiency and a bonding force equivalent to those of the silver electrode solar cell can be achieved. Comparing the test results of comparative example 3 and example 1, it can be seen that the bonding force between the thickened copper layer and the copper seed layer is weak in the conventional preparation method of the copper electrode, which may be caused by oxidation of the surface of the copper seed layer, and the seed layer is easily damaged in the etching process, thereby resulting in lower photoelectric conversion efficiency. As can be seen from comparison of example 2 and example 1, in the case where the preparation of the third metal layer is not performed, the separation occurs between the second metal layer and the fourth metal layer, because the second metal layer is easily oxidized after the protection of the third metal layer is lost, resulting in poor effect of directly performing copper electroplating on the surface of the second metal layer, thereby resulting in lower photoelectric conversion efficiency of the solar cell. Comparing comparative example 1 with example 1, it can be seen that the second metal layer is not prepared to protect the first metal layer, which results in easy damage to the first metal layer during etching, and thus lower photoelectric conversion efficiency of the solar cell.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. The scope of the application is therefore intended to be covered by the appended claims, and the description and drawings may be interpreted in accordance with the contents of the claims.

Claims

1. A method for preparing an electrode, comprising:

providing a substrate;

Preparing a first metal layer on the surface of the substrate, wherein the material of the first metal layer includes copper, and the preparation method of the first metal layer includes physical vapor deposition;

Preparing a second metal layer on the surface of the first metal layer, wherein the material of the second metal layer comprises at least one of titanium, titanium alloy, nickel, nickel alloy, chromium, chromium alloy, silver, silver alloy, molybdenum, molybdenum alloy, manganese and manganese alloy;

Preparing a third metal layer on the surface of the second metal layer, wherein the material of the third metal layer includes copper, and the preparation method of the third metal layer includes physical vapor deposition;

Preparing a fourth metal layer on the surface of the third metal layer, wherein the material of the fourth metal layer includes copper, and the preparation method of the fourth metal layer includes electroplating;

Preparing a mask layer on the surface of the fourth metal layer;

Performing a first etching on the fourth metal layer and the third metal layer exposed from the mask layer using a first etching solution;

Performing a second etching on the second metal layer exposed from the mask layer using a second etching solution;

Performing a third etching on the first metal layer exposed from the mask layer using a third etching solution;

The mask layer is removed.

2. The method for preparing an electrode according to claim 1, characterized in that the thickness of the first metal layer is 10 nm to 200 nm;

And/or, the thickness of the second metal layer is 10nm to 200nm;

And/or, the thickness of the third metal layer is 10nm to 200nm;

And/or, the thickness of the fourth metal layer is 5 μm to 20 μm.

3. The method for preparing an electrode according to any one of claims 1 to 2, characterized in that before preparing the fourth metal layer on the surface of the third metal layer, it also includes:

The third metal layer is first pickled to remove oxide on the surface of the third metal layer.

4. The method for preparing an electrode according to claim 1, characterized in that the first etching solution comprises an acidic etching solution or an alkaline etching solution, the acidic etching solution comprises 120 g/L to 180 g/L of copper chloride and 30 g/L to 70 g/L of hydrochloric acid, and the alkaline etching solution comprises copper chloride and ammonia water with a mass volume concentration of 120 g/L to 180 g/L, respectively;

And/or, the second etching solution comprises 5% to 15% by mass of hydrogen peroxide and 1% to 5% by mass of phosphoric acid, and the pH value of the second etching solution is 1 to 3;

And/or, the third etching solution comprises 0.1% to 0.5% by mass of sulfuric acid and 1% to 3% by mass of sodium persulfate, and the pH range of the third etching solution is 1 to 3.

5. The method for preparing an electrode according to claim 1, characterized in that the temperature of the first etching is 30° C. to 50° C.;

And/or, the first etching time is 60s to 120s;

And/or, the temperature of the second etching is 30° C. to 50° C.;

And/or, the second etching time is 10s to 60s;

And/or, the temperature of the third etching is 20° C. to 30° C.;

And/or, the third etching time is 10s to 60s.

6. The method for preparing an electrode according to claim 1, characterized in that before preparing a mask layer on the surface of the fourth metal layer, it also comprises:

The fourth metal layer is subjected to a second acid wash to remove oxide on the surface of the fourth metal layer.

7. The method for preparing an electrode according to claim 1, characterized in that after removing the mask layer, the method further comprises:

A fifth metal layer is prepared on the surface of the fourth metal layer, and a material of the fifth metal layer includes at least one of silver, silver alloy, tin and tin alloy.

8. The method for preparing an electrode according to claim 7, characterized in that after preparing the fifth metal layer on the surface of the fourth metal layer, the method further comprises: annealing the electrode;

The temperature of the annealing treatment is 100° C. to 150° C., and/or the holding time of the annealing treatment is 0.5 h to 3 h.

9. An electrode, characterized in that it is prepared by the method for preparing an electrode according to any one of claims 1 to 8, comprising:

A first metal layer, a second metal layer, a third metal layer and a fourth metal layer are stacked in sequence;

The material of the first metal layer includes copper; the material of the second metal layer includes at least one of titanium, titanium alloy, nickel, nickel alloy, chromium, chromium alloy, silver, silver alloy, molybdenum, molybdenum alloy, manganese and manganese alloy; the material of the third metal layer includes copper; the material of the fourth metal layer includes copper.

10. A solar cell, characterized in that it comprises: an electrode prepared by the method for preparing an electrode according to any one of claims 1 to 8, or an electrode according to claim 9.