CN112951929B - Solar cell electrode, preparation method thereof and solar cell - Google Patents

Abstract

The invention discloses a preparation method of a solar cell electrode, which comprises the following steps: applying Ca to the area of the silicon wafer where the electrode is to be formed ₂ N two-dimensional material solution, and then solidifying to obtain the solar cell electrode; wherein, the Ca ₂ The N two-dimensional material solution is Ca ₂ A mixed solution of a N-dimensional material and an organic solvent, the Ca ₂ N two-dimensional material composed of Ca ₃ N ₂ Is prepared by high-temperature treatment, or the Ca2N two-dimensional material is prepared from Ca ₃ N ₂ And the mixture of Ca is prepared by high-temperature treatment. Correspondingly, the invention also discloses a solar cell electrode and a solar cell. By implementing the invention, the shading area of the solar cell electrode can be reduced, and the conversion efficiency of the solar cell is improved.

Description

Solar cell electrode and preparation method thereof, solar cell

technical field

The invention relates to the technical field of crystalline silicon solar cells, in particular to a method for preparing a solar cell electrode, a solar electrode and a solar cell.

Background technique

Solar cell electrodes mainly play the role of collecting current, and the resistivity and other properties of the electrode material itself have a great influence on the extraction of photoelectricity from solar cells. At the same time, since the electrodes are printed on the light-receiving surface, the light-receiving surface of the solar cell will be reduced; therefore, the electrode of the solar cell is one of the important factors determining the conversion efficiency of the solar cell.

Most of the existing electrode materials are silver electrode pastes, which are screen printed and sintered to obtain solar cell electrodes. However, its application in some advanced batteries (such as HJT batteries) is limited due to its high sintering temperature. There are generally three existing solutions: one is to reduce the sintering temperature of the silver paste, and still use the process of screen printing and sintering; the other is to cover the electrode mold with electrode pattern grinding on the silicon wafer, and then vacuum Electrodes are obtained by evaporating copper metal; there is another method of selectively depositing copper electrodes on battery sheets using a salt solution containing copper metal. These methods are either difficult to effectively reduce the damage to the solar cell structure caused by firing, or the preparation process is complicated and the cost is high. In addition, the above-mentioned electrodes are all opaque, which will reduce the light-receiving area on the surface of the solar cell and reduce the conversion efficiency of the solar cell.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a solar cell electrode, the preparation cost of which is low, and the prepared solar cell electrode is transparent, which can effectively improve the conversion efficiency of the solar cell.

The technical problem still to be solved by the present invention is to provide a solar cell electrode.

The technical problem still to be solved by the present invention is to provide a solar cell.

In order to solve the above-mentioned technical problems, the present invention provides a method for preparing a solar cell electrode, which includes: applying a Ca2N _two -dimensional material solution on a silicon wafer to the region where the electrode is to be formed, and then curing to obtain a solar cell electrode;

Wherein, the Ca ₂ N two-dimensional material solution is a mixed solution of Ca ₂ N two-dimensional material and an organic solvent;

The Ca ₂ N two-dimensional material is prepared from Ca ₃ N ₂ through high temperature treatment, or

The Ca2N two-dimensional material is prepared from a mixture of Ca ₃ N ₂ and Ca through high-temperature treatment.

As an improvement of the above-mentioned technical solutions, including:

(1) Loading the mold onto the silicon wafer, the mold comprising a sealing plate and a hollowed out area, the hollowed out area corresponds to the area to be formed on the silicon wafer;

(2) injecting a Ca ₂ N two-dimensional material solution into the hollow area;

(3) freeze-dry the silicon wafer obtained in step (2), and then remove the mold to obtain the finished solar cell electrode.

As an improvement of the above technical solution, the organic solvent is dimethyl carbonate or propylene carbonate, and the concentration of Ca ₂ N in the Ca ₂ N two-dimensional material solution is 0.1˜5 g/L.

As an improvement of the above technical solution, the preparation method of the Ca ₂ N two-dimensional material solution is:

(1) Mix Ca ₃ N ₂ powder and calcium powder evenly according to the molar ratio of 1: (1-1.5) to obtain a mixture;

(2) compressing the mixture with a pressure of 0.5 to 0.7 GPa;

(3) Encapsulating the pressed mixture in a vacuum container and performing heat treatment to obtain a Ca ₂ N two-dimensional material;

(4) Dispersing the Ca ₂ N two-dimensional material into an organic solvent to obtain a finished Ca ₂ N two-dimensional material solution;

Wherein, the heat treatment temperature is 1050-1200° C.; the heat treatment time is 30-50 hours.

As an improvement of the above technical solution, in step (3), the compressed mixture is rolled into molybdenum foil and put into a vacuum ampoule, and then subjected to high temperature treatment in a tube furnace.

As an improvement of the above technical solution, in step (4), the Ca ₂ N two-dimensional material is mixed with dimethyl carbonate, and ultrasonically treated for 80-100 minutes to obtain a finished Ca ₂ N two-dimensional material solution.

As an improvement of the above technical solution, the mold is made of polyvinylidene fluoride, polytetrafluoroethylene or ABS.

Correspondingly, the present invention also discloses a solar cell electrode, which is prepared by the above-mentioned preparation method of the solar cell electrode.

Correspondingly, the present invention also discloses a solar cell, which includes the above-mentioned solar cell electrode.

As an improvement of the above technical solution, the solar cell is an HJT cell.

Implement the present invention, have following beneficial effect:

1. The preparation method of the solar cell electrode in the present invention adopts Ca ₂ N two-dimensional material solution to solidify to obtain the electrode. Since the Ca ₂ N two-dimensional material is transparent and does not block the light-receiving surface, the conversion efficiency of the solar cell is improved. At the same time, the Ca ₂ N two-dimensional material has good electrical conductivity, which can effectively reduce the transmission loss of photoelectricity and further improve the conversion efficiency.

2. The preparation method of the solar cell electrode in the present invention is prepared by freeze-drying process, and its operating temperature is low, which will not cause damage to the structure of the solar cell electrode. At the same time, the overall process is simple, easy to operate, economical and environmentally friendly, and suitable for large-scale production.

3. When the solar cell in the present invention is applied to the HJT cell, it can not only effectively reduce the damage caused by high temperature to the amorphous silicon film, but also because the strength requirement for the silicon wafer is low, so a thinner silicon wafer can be used, which reduces the production cost. The cost improves the conversion efficiency of the HJT battery.

Description of drawings

Fig. 1 is the flowchart of the solar cell electrode preparation method in an embodiment of the present invention;

Fig. 2 is the top view of mold in an embodiment of the present invention;

Fig. 3 is a front view of a mold in an embodiment of the present invention.

detailed description

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

The invention provides a method for preparing a solar cell electrode, which comprises: applying a Ca2N _two -dimensional material solution on a silicon wafer to a region where the electrode is to be formed, and then curing to obtain a solar cell electrode;

Specifically, see Figure 1, which includes:

S1: loading the mold onto the silicon wafer;

Among them, according to the type of solar cell, the corresponding passivation film, heterojunction film layer and/or anti-reflection film can be formed on the surface of the silicon wafer, and then the mold is loaded on the corresponding film layer. Exemplarily, when the solar cell is a PERC cell, an SiN _x anti-reflection film should be formed on the front side of the silicon wafer, and an AlO _x film, SiO _x film and SiN _x film should be formed on the back side of the silicon wafer; when the solar cell is a HJT cell, it should be Form an i-type amorphous silicon film, a p-type amorphous silicon film, and a TCO film on the front of the silicon wafer, and form an i-type amorphous silicon film, an n-type amorphous silicon film, and a TCO film on the back of the silicon wafer.

Referring to FIG. 2 and FIG. 3 , the mold 1 includes a sealing plate 11 and a hollowed out area 12 , wherein the hollowed out area 12 corresponds to the area on the silicon wafer where electrodes are to be formed. The height of the hollow area 12 is 0.5-2 mm, for example, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, but not limited thereto. The width and length of the hollow area 12 can be determined according to the shape of the solar cell electrode, for example, 20-200 μm, but not limited thereto.

Specifically, the mold 1 has the same shape as the silicon wafer, and its material is polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) or ABS, but not limited thereto. Preferably, its material is PVDF.

S2: injecting a Ca ₂ N two-dimensional material solution into the hollow area;

Among them, the Ca ₂ N two-dimensional material can be prepared by high-temperature treatment of Ca ₃ N ₂ ; it can also be prepared by high-temperature treatment of a mixture of Ca ₃ N ₂ and calcium. Preferably, Ca ₃ N ₂ and calcium powder are used as raw materials to prepare Ca ₂ N two-dimensional materials. This method has a high conversion rate, and the stability of the two-dimensional materials is higher, and the sheet stacking structure is better, which is conducive to improving solar energy. The conversion efficiency of the battery.

Specifically, the preparation method of the Ca ₂ N two-dimensional material solution includes:

(1) Mix Ca ₃ N ₂ powder and calcium powder evenly according to the molar ratio of 1: (1-1.5) to obtain a mixture;

Wherein, the molar ratio of Ca ₃ N ₂ to Ca is 1:(1˜1.5), exemplarily 1:1, 1:1.2, 1:1.3, but not limited thereto. Preferably, the molar ratio of Ca ₃ N ₂ to Ca is 1: (1-1.5). By controlling a small amount of excess calcium powder, a small amount of Ca remains in the prepared product, thereby effectively preventing the hydrolysis of the Ca ₂ N two-dimensional material , to improve its stability. The particle size of Ca ₃ N ₂ powder and calcium powder is ≤50 μm, so as to realize the sufficient mixing of the two and increase the yield of Ca ₂ N.

(2) compressing the mixture with a pressure of 0.5 to 0.7 GPa;

Specifically, a hydraulic press is used to press the mixture, and the pressing pressure is 0.5-0.7 GPa, exemplarily 0.52 GPa, 0.55 GPa, 0.63 GPa, 0.68 GPa, but not limited thereto. Preferably, the pressing pressure is 0.55-0.6 GPa.

(3) Encapsulating the pressed mixture in a vacuum container and performing heat treatment to obtain a Ca ₂ N two-dimensional material;

Specifically, the pressed mixture is first rolled into molybdenum foil, gold foil, platinum foil or niobium foil, and then placed in a vacuum ampoule; then high-temperature heat treatment is carried out in a tube furnace (protected by an inert gas atmosphere), and cooled after heat treatment to room temperature, a bulk Ca ₂ N material is obtained.

Wherein, the heat treatment temperature is 1050-1200° C., and when the heat treatment temperature is lower than 1050° C., the obtained Ca2N two-dimensional material has low purity and poor electrical conductivity. Preferably, the heat treatment temperature is 1050-1120°C, exemplarily 1080°C, 1100°C, 1110°C, but not limited thereto.

(4) Dispersing the Ca ₂ N two-dimensional material into an organic solvent to obtain a finished Ca ₂ N two-dimensional material solution;

Wherein, the organic solvent may be propylene carbonate, dimethyl carbonate, toluene, but not limited thereto. Preferably, the organic solvent is dimethyl carbonate, which has a relatively high melting point and is environmentally friendly.

Specifically, the Ca ₂ N two-dimensional material is mixed with dimethyl carbonate, and ultrasonically treated for 80-100 minutes to obtain a finished Ca ₂ N two-dimensional material solution.

Specifically, the concentration of Ca ₂ N in the Ca ₂ N two-dimensional material solution is 0.1-5 g/L, exemplarily 0.2 g/L, 0.5 g/L, 1 g/L, 1.5 g/L, 2.2 g/L , 3.5g/L, 4.5g/L, but not limited thereto. Preferably, its concentration is 0.2-1 g/L.

S3: freeze-dry the silicon wafer obtained in step S2, and then remove the mold to obtain the finished solar cell electrode.

Correspondingly, the present invention also discloses a solar cell electrode, which is prepared by the above-mentioned preparation method.

Correspondingly, the present invention also discloses a solar cell, which adopts the above-mentioned solar cell electrode. Specifically, the solar cell electrode in the present invention can be applied to various types of solar cells, such as PERC cells, IBC cells, HJT cells, and Topcon cells, but is not limited thereto. Preferably, the solar cell electrode in the present invention is applied to the HJT cell, which can effectively reduce the thickness of the silicon slice of the HJT cell, and due to the low operating temperature, reduces damage to the amorphous silicon film layer and improves conversion efficiency.

The present invention is described below with specific embodiment:

Example 1 Preparation of Ca ₂ N two-dimensional material solution

This embodiment provides a method for preparing a Ca ₂ N two-dimensional material solution, which specifically includes:

(1) Mix Ca ₃ N ₂ powder (D99=20 μm) and calcium powder (D99=15 μm) uniformly at a molar ratio of 1:1.3 to obtain a mixture;

(2) the mixture is compressed using a pressure of 0.56GPa;

(3) Encapsulating the pressed mixture in platinum foil, and then heat-treating at 1150°C for 30h, the Ca ₂ N two-dimensional material was obtained;

(4) Disperse 10 mg of the Ca ₂ N two-dimensional material into 20 mL of propylene carbonate to obtain a finished Ca ₂ N two-dimensional material solution.

Example 2

This embodiment provides a method for preparing a Ca ₂ N two-dimensional material solution, which specifically includes:

(1) Mix Ca ₃ N ₂ powder (D99=20 μm) and calcium powder (D99=15 μm) according to the molar ratio of 0.8:1 to obtain a mixture;

(2) the mixture is compressed using a pressure of 0.56GPa;

(3) Encapsulating the pressed mixture in platinum foil, and then heat-treating at 1150°C for 30h, the Ca ₂ N two-dimensional material was obtained;

(4) Disperse 10 mg of the Ca ₂ N two-dimensional material into 20 mL of dimethyl carbonate to obtain a finished Ca ₂ N two-dimensional material solution.

Example 3

This embodiment provides a kind of HJT battery, and its preparation method is as follows:

(1) Provide N-type monocrystalline silicon wafers and make texture;

(2) sequentially depositing an intrinsic amorphous silicon layer and an n-type amorphous silicon layer on the front side of the silicon wafer;

(3) sequentially depositing an intrinsic amorphous silicon layer and a p-type amorphous silicon layer on the backside of the silicon wafer;

(4) Deposit TCO layers on the front and back sides of the silicon wafer;

(5) Prepare the front electrode. Specifically, first place the mold for the front electrode (pvdf material, 1mm high, 210mm×210mm, and the width of the hollow area is 100μm) on the front TCO, and then place the Ca prepared in Example 1 ₂ N two-dimensional material solution; then freeze-dried at -25 °C, and finally removed the mold;

(6) Prepare the back electrode. Specifically, first place the mold for the back electrode (pvdf material, 1mm high, 210mm×210mm, and the width of the hollow area is 100μm) on the back TCO, and then place the Ca prepared in Example 1 ₂ N two-dimensional material solution; then freeze-dried at -25°C, and finally removed the mold; the finished HJT battery was obtained.

Example 4

This embodiment provides a kind of HJT battery, and its preparation method is as follows:

(1) Provide N-type monocrystalline silicon wafers and make texture;

(2) sequentially depositing an intrinsic amorphous silicon layer and an n-type amorphous silicon layer on the front side of the silicon wafer;

(3) sequentially depositing an intrinsic amorphous silicon layer and a p-type amorphous silicon layer on the backside of the silicon wafer;

(4) Deposit TCO layers on the front and back sides of the silicon wafer;

(5) Prepare the front electrode. Specifically, first place the mold for the front electrode (pvdf material, 1mm high, 210mm×210mm, and the width of the hollow area is 100μm) on the front TCO, and then place the Ca prepared in Example 2 ₂ N two-dimensional material solution; then freeze-dried at -25 °C, and finally removed the mold;

(6) Prepare the back electrode. Specifically, first place the mold for the back electrode (pvdf material, 1mm high, 210mm×210mm, and the width of the hollow area is 100μm) on the back TCO, and then place the Ca prepared in Example 2 ₂ N two-dimensional material solution; then freeze-dried at -25°C, and finally removed the mold; the finished HJT battery was obtained.

The conventional HJT battery (low temperature silver paste electrode), the HJT battery obtained in Example 3 and Example 4 were tested, and the results are as follows:

J_sc(mA/cm²) V_oc(mV) FF/% Eff(%) Conventional HJT battery 41.6 710.6 82.4 24.4 Example 3 42.3 718.3 83.6 25.2 Example 4 42.4 720.5 83.2 25.5

It can be seen from the above table that the solar cell electrode prepared by the present invention can increase the conversion efficiency of the HJT cell to more than 25.2%.

The above description is a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered Be the protection scope of the present invention.

Claims (9)

1. A method for preparing a solar cell electrode, comprising:

(1) Loading a mold onto a silicon wafer, wherein the mold comprises a sealing plate and a hollow-out area, and the hollow-out area corresponds to an area on the silicon wafer where an electrode is to be formed;

(2) Adding Ca ₂ Injecting N two-dimensional material solution into the hollow area;

(3) Freeze-drying the silicon wafer obtained in the step (2), and then removing the die to obtain a finished product of the solar cell electrode;

wherein, the Ca ₂ The N two-dimensional material solution is Ca ₂ A mixed solution of an N two-dimensional material and an organic solvent;

the Ca ₂ N two-dimensional material composed of Ca ₃ N ₂ Is obtained by high temperature treatment, or

The Ca ₂ N two-dimensional material composed of Ca ₃ N ₂ And the mixture of Ca is prepared by high-temperature treatment.

2. The method of claim 1, wherein the organic solvent is dimethyl carbonate or propylene carbonate, and the Ca is ₂ Ca in N two-dimensional material solution ₂ The concentration of N is 0.1-5 g/L.

3. The method for producing a solar cell electrode according to claim 1, wherein the Ca is ₂ The preparation method of the N two-dimensional material solution comprises the following steps:

(1) Adding Ca ₃ N ₂ The powder and the calcium powder are mixed according to the molar ratio of 1: (1-1.5) uniformly mixing to obtain a mixture;

(2) Pressing the mixture by adopting the pressure of 0.5-0.7 GPa;

(3) Packaging the pressed mixture in a vacuum container, and performing heat treatment to obtain Ca ₂ N two-dimensional material;

(4) Mixing Ca ₂ Dispersing the N two-dimensional material into an organic solvent to obtain Ca ₂ N two-dimensional material solution finished products;

wherein the heat treatment temperature is 1050-1200 ℃; the heat treatment time is 30-50 h.

4. The method of claim 3, wherein in the step (3), the pressed mixture is rolled into a molybdenum foil, and placed in a vacuum ampoule, and then subjected to a high temperature treatment in a tube furnace.

5. The method for preparing an electrode for a solar cell according to claim 3, wherein in the step (4), ca is added ₂ Mixing the N two-dimensional material with dimethyl carbonate, and carrying out ultrasonic treatment for 80-100 min to obtain Ca ₂ And (5) obtaining a finished product of the N two-dimensional material solution.

6. The method of claim 1, wherein the mold is made of polyvinylidene fluoride, polytetrafluoroethylene, or ABS.

7. A solar cell electrode produced by the method for producing a solar cell electrode according to any one of claims 1 to 6.

8. A solar cell comprising the solar cell electrode of claim 7.

9. The solar cell of claim 8, wherein the solar cell is an HJT cell.

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