CN114267580A - Backside structure etching method and etching solution for double-sided PERC solar cells - Google Patents
Backside structure etching method and etching solution for double-sided PERC solar cells Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
本发明公开了一种双面PERC太阳能电池的背面结构刻蚀方法及其刻蚀液，使晶硅片的背面浸入刻蚀液中，在温度8℃～40℃下刻蚀30s～180s，对晶硅片背面的金字塔形貌结构的塔尖进行刻蚀削平形成四棱台形貌结构。整个刻蚀方法工艺简单，与目前的刻蚀工艺兼容，能对晶硅片背面的金字塔形貌结构的塔尖进行刻蚀削平形成四棱台形貌结构，该四棱台形貌结构的顶面为平面，易于后续钝化膜的沉积，反射率可控，同时兼顾电池的光学和电学性能，得到的双面太阳能电池背面效率高，双面率高；同时所采用的刻蚀液不含氮，有效避免了现有技术酸刻蚀中的硝酸排放，废液处理成本低，对环保压力小，而且原料化学药液成本低，易于获得。
The invention discloses a method for etching the backside structure of a double-sided PERC solar cell and an etching solution. The spire of the pyramid shape structure on the backside of the crystalline silicon wafer is etched and flattened to form a quadrangular pyramid shape structure. The whole etching method has a simple process and is compatible with the current etching process. The surface is flat, which is easy for subsequent deposition of passivation film, and the reflectivity is controllable. At the same time, the optical and electrical properties of the cell are taken into account. The obtained double-sided solar cell has high backside efficiency and high double-sided ratio; at the same time, the etching solution used does not contain Nitrogen effectively avoids the discharge of nitric acid in acid etching in the prior art, the waste liquid treatment cost is low, the pressure on environmental protection is small, and the raw chemical liquid is low in cost and easy to obtain.
Description
Technical Field
The invention belongs to the technical field of double-sided PERC solar cells, and particularly relates to a back structure etching method and etching liquid of a double-sided PERC solar cell.
Background
The crystalline silicon solar cell always occupies the leading position of the photovoltaic power generation market, and the development targets of improving the conversion efficiency of the cell and reducing the cost are in the whole industry. The passivation emitter and back surface cell (PERC) technology can greatly improve the cell efficiency only by adding the steps of back passivation and laser grooving on the basis of the conventional aluminum back surface field (Al-BSF) solar cell technology, and is the most mainstream high-efficiency solar cell technology in the current market. Compared with the traditional single-sided light receiving solar cell, the double-sided solar cell utilizes the front light receiving surface and the back light receiving surface, so that the short-circuit current can be greatly improved, the conversion efficiency of the solar cell is further improved, and the cost is reduced.
The back structure of the double-sided solar cell can effectively improve the absorption of ground and environment reflected light, and is an important component of the double-sided solar cell. The whole process of the PERC battery comprises the following steps: 1. texturing-2, diffusion-3, laser SE-4, etching (back polishing) -5, high-temperature annealing-6, back surface coating (aluminum oxide and silicon nitride) -7, front surface coating (silicon nitride) -8, laser grooving-9, screen printing-10 and sintering. At present, two general etching polishing modes in the industry are acid polishing and alkali polishing. And the acid polishing adopts mixed acid liquid of hydrofluoric acid and nitric acid to polish and etch the back of the diffused silicon wafer. The reflectivity of the back surface of the acid polishing is 25-30%, the polishing effect is general, in order to improve the reflectivity of the back surface, the concentration of nitric acid is usually required to be very high (more than 60%), and the consumption cost of chemical liquid is high. In addition, the emission of nitrogen in nitric acid causes great pressure on environmental protection, and the treatment cost of acid waste liquid is high. In order to reduce nitrogen emission, an alkali polishing process is developed, but the alkali polishing process needs to add an alkali polishing groove type device on the basis of a chain type device. In addition, the alkali polishing process is incompatible with the current SE process, the SE area needs to be protected by additionally adding an oxidation process in the process of adding the SE, the risk of process pollution is increased, and the process is complex and unstable.
In summary, the prior art has the following drawbacks: 1. the acid liquor cost of the acid etching process is high, the waste water containing nitrate nitrogen is not environment-friendly, and the waste water treatment cost is high; 2. the alkali back polishing process needs three sets of equipment (an oxidation furnace, chain type removal of the phosphorus silicon glass on the back surface and groove type alkali polishing), the equipment investment cost is high, the compatibility with the SE process is poor, the whole process is complex, the process pollution risk is increased, and the process is unstable. In addition, the alkali polishing needs to be matched with the purchase of additional alkali polishing additives for use.
In addition, the double-sided battery structure prepared by acid etching has low front efficiency, low current and open voltage and poor passivation effect. The double-sided battery prepared by alkaline polishing has high front efficiency and good passivation effect, but the efficiency of the back battery is low due to high back reflectivity, so that the double-sided rate of the PERC solar battery is low. Therefore, the back surface structure obtained by the above two methods cannot effectively balance the back surface reflectivity and the passivation effect, and does not exert the advantages of the double-sided battery.
Disclosure of Invention
In view of the above disadvantages, the present invention aims to provide a method for etching a backside structure of a double-sided PERC solar cell and an etching solution thereof, which have a simple process, can etch and flatten a pyramid tip of a pyramid morphology structure on the backside of a crystalline silicon wafer to form a quadrangular frustum morphology structure, and simultaneously give consideration to both backside reflectivity and passivation effect.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a back structure etching method of a double-sided PERC solar cell comprises the following steps:
(1) preparing a diffused crystal silicon wafer, wherein the back surface of the crystal silicon wafer is provided with a pyramid appearance structure, the bottom side of the pyramid appearance structure is 1-5 microns, and the height of the pyramid appearance structure is 0.7-3.5 microns;
(2) preparing an etching solution: mixing a fluoride ion source, a chloride ion source, an oxidant and deionized water to obtain etching liquid, wherein the concentration of the fluoride ion source is 0.1-8 mol/L, the concentration of the chloride ion source is 0.01-13 mol/L, and the concentration of the oxidant is 0.01-3 mol/L;
(3) back etching: the method comprises the following steps of putting a crystal silicon wafer on a conveying device, conveying the crystal silicon wafer forwards by the conveying device, immersing the back of the crystal silicon wafer into etching liquid, etching the crystal silicon wafer at the temperature of 8-40 ℃ for 30-180 s, and etching and flattening the pyramid tip of the pyramid appearance structure on the back of the crystal silicon wafer to form a quadrangular frustum appearance structure, wherein the side length of the bottom surface of the quadrangular frustum appearance structure is 1-5 micrometers, the side length of the top surface of the quadrangular frustum appearance structure is 0.3-3 micrometers, and the height of the quadrangular frustum appearance structure is 0.3-3 micrometers; the top surface of the quadrangular frustum pyramid morphology structure is a plane, and passivation is easy.
As a preferable scheme of the invention, the crystal silicon wafer is a P-type silicon wafer or an N-type silicon wafer.
As a preferred embodiment of the present invention, the fluoride ion source is selected from hydrofluoric acid.
In a preferred embodiment of the present invention, the chlorine-containing ion source is selected from hydrochloric acid, sodium hypochlorite, sodium chlorite, chlorine dioxide, chlorine gas, sodium chlorate or sodium perchlorate.
In a preferred embodiment of the present invention, the oxidizing agent is one or more selected from sodium persulfate, hydrogen peroxide, acetic acid, peroxyacetic acid, potassium permanganate, and concentrated sulfuric acid.
As a preferable aspect of the present invention, the conveying apparatus is preferably a chain type apparatus. In other embodiments, the conveying device may be other devices as long as the back surface of the crystal silicon wafer can be immersed in the etching solution during conveying.
According to a preferable scheme of the invention, an additive is further added in the step (2), and the mass ratio of the additive to the etching solution is 0.2-5: 100.
As a preferable scheme of the invention, the additive comprises the following components in parts by mass: 0.1-5 parts by mass of sodium dodecyl sulfate, 1-3 parts by mass of sodium citrate, 0.5-3 parts by mass of guar gum and 100 parts by mass of water.
In a preferable scheme of the invention, the additive is one or a mixture of sodium dodecyl benzene sulfonate, sodium citrate and guar gum.
An etching liquid used in a back structure etching method of a double-sided PERC solar cell.
The invention has the beneficial effects that: the method for etching the back structure of the double-sided PERC solar cell is simple in process, is compatible with the existing etching process, can be used for etching and flattening the pyramid tip of the pyramid shape structure on the back of the crystal silicon wafer to form the quadrangular frustum shape structure, is easy for subsequent deposition of a passivation film, is controllable in reflectivity, and simultaneously gives consideration to the optical and electrical properties of the cell, and the obtained double-sided PERC solar cell is high in back efficiency and double-sided rate; meanwhile, the adopted etching liquid does not contain nitrogen, thereby effectively avoiding the emission of nitric acid in acid etching in the prior art, having low waste liquid treatment cost and small pressure on environmental protection, and the chemical liquid medicine of the raw materials has low cost and is easy to obtain, thereby reducing the pollution to the environment while reducing the production cost.
The invention is further illustrated below with reference to the figures and examples.
Drawings
FIG. 1 is a SEM surface structure diagram of the back surface of a silicon wafer before etching.
FIG. 2 is a structural view of the SEM cross section of the back side of a crystalline silicon wafer before etching.
FIG. 3 is a SEM surface structure diagram of example 1 of the present invention.
FIG. 4 is a structural view of a SEM cross section in example 1 of the present invention.
FIG. 5 is a SEM surface structure diagram of example 2 of the present invention.
FIG. 6 is a structural view of a SEM cross section in example 2 of the present invention.
FIG. 7 is a SEM surface structure diagram of example 3 of the invention.
FIG. 8 is a SEM cross-sectional view of example 4 of the present invention.
FIG. 9 is a SEM surface structure diagram of comparative example 1 of the present invention.
FIG. 10 is a SEM sectional structural view of comparative example 1 of the present invention.
Detailed Description
Example 1: in this embodiment, hydrofluoric acid, sodium hypochlorite, deionized water and an additive are prepared, and in this embodiment, the sodium hypochlorite has an effect of an oxidant at the same time, and no additional oxidant is required to be added. Mixing hydrofluoric acid, sodium hypochlorite and deionized water to obtain etching liquid, wherein the concentration of the sodium hypochlorite is 0.15mol/L, the concentration of the hydrofluoric acid is 0.8mol/L, adding an additive into the etching liquid, and the mass ratio of the additive to the etching liquid is 2: 100. the additive comprises 2 parts by mass of sodium dodecyl benzene sulfonate, 2 parts by mass of sodium citrate, 0.3 part by mass of guar gum and 100 parts by mass of water.
In this embodiment, taking a diffused P-type monocrystalline silicon wafer as an example, referring to fig. 1 and fig. 2, a pyramidal appearance structure is formed on the back surface of the monocrystalline silicon wafer, and the bottom side of the pyramidal appearance structure is 1-5 micrometers long and the height thereof is the bottom side
I.e., a height of about 0.7 to 3.5 microns, as shown in fig. 1 and 2. In other embodiments, the single crystal silicon wafer may also be a P-type silicon wafer. In other embodiments, the single crystal silicon wafer may also be an N-type silicon wafer.
And placing the diffused monocrystalline silicon wafer into the etching solution, and etching for 90s at the reaction temperature of 25 ℃ to realize etching and flattening the pyramid tip of the pyramid morphology structure on the back of the monocrystalline silicon wafer to obtain a quadrangular frustum morphology structure, as shown in fig. 3 and 4. The top surface of the quadrangular frustum morphology structure is a smooth plane, so that the deposition of a passive film is easy, and the optical and electrical properties of the battery are considered.
Example 2: the embodiment provides a method for etching a back structure of a double-sided PERC solar cell, which is basically the same as that in embodiment 1, except that hydrofluoric acid, hydrogen peroxide, hydrochloric acid and an additive are prepared. Mixing hydrofluoric acid, hydrogen peroxide and hydrochloric acid to obtain etching liquid, wherein the concentration of the hydrofluoric acid is 0.5mol/L, the concentration of the hydrogen peroxide is 0.5mol/L, and the concentration of the hydrochloric acid is 9 mol/L; adding an additive into the etching liquid, wherein the mass ratio of the additive to the etching liquid is 1: 100. the additive comprises 3 parts by mass of sodium dodecyl benzene sulfonate, 1 part by mass of sodium citrate, 1.5 parts by mass of guar gum and 100 parts by mass of water.
And placing the diffused monocrystalline silicon wafer into the etching solution, and etching for 60s at the reaction temperature of 15 ℃ to realize etching and flattening the pyramid tip of the pyramid morphology structure on the back of the monocrystalline silicon wafer to obtain a quadrangular frustum morphology structure, as shown in fig. 5 and 6.
Example 3: this example provides a method for etching a backside structure of a double-sided PERC solar cell, which is substantially the same as example 1, except that hydrofluoric acid, sodium perchlorate, and hydrochloric acid are prepared. In this embodiment, sodium perchlorate has the effect of an oxidant at the same time, and no additional oxidant is needed, and certainly, in other embodiments, an oxidant may be added. Mixing hydrofluoric acid, sodium perchlorate and hydrochloric acid to obtain etching liquid, wherein the concentration of the hydrofluoric acid is 2mol/L, the concentration of the sodium perchlorate is 0.3mol/L, and the concentration of the hydrochloric acid is 8 mol/L;
and placing the diffused monocrystalline silicon wafer into the etching solution, and etching at the reaction temperature of 30 ℃ for 120s to realize etching and flattening the pyramid tip of the pyramid morphology structure on the back of the monocrystalline silicon wafer to obtain a quadrangular frustum morphology structure, as shown in fig. 7 and 8.
Comparative example 1: placing the diffused monocrystalline silicon wafer in HF and HNO3Treating in mixed acid solution at 15 deg.C for 50 s; wherein the mass percent of HF in the mixed acid liquid is 15%, and HNO3The mass percentage of the second layer is 60%, the etched structure is shown in fig. 9 and 10, the whole pyramid shape structure on the back surface is etched into a spherical crown-shaped convex structure, and the outer surface is a smooth surface.
Solar cells prepared according to the technical flow of the double-sided PERC cell in the examples 1-3 and the comparative example 1 are compared to test the performance of the solar cells, and the specific results are shown in the following table 1:
TABLE 1
| Front side efficiency (%) | Back surface efficiency (%) | Double area ratio (%) | |
| Example 1 | 22.31 | 17.56 | 78.71 |
| Example 2 | 22.28 | 17.71 | 79.49 |
| Example 3 | 22.35 | 17.38 | 77.76 |
| Comparative example 1 | 22.3 | 16.54 | 74.17 |
By comparison in table 1, the front efficiency of the solar cell prepared from the monocrystalline silicon wafer processed by the back structure etching method of the double-sided PERC solar cell according to the double-sided PERC cell process flow is basically equal, the back efficiency is respectively improved by 1.02%, 1.17% and 0.84%, and the double-sided efficiency is respectively improved by 4.54%, 5.32% and 3.59%. The back efficiency and the double-sided rate are greatly improved, and finally the battery efficiency is improved.
According to the etching method for the back structure of the double-sided PERC solar cell, disclosed by the invention, the tip of the pyramid appearance structure is selectively etched by reasonably controlling the etching time and temperature, because chloride ions are combined with the suspension bonds on the silicon surface, but the strengths of the silicon suspension bonds in different surface orientations are different, the (100) crystal face of the pyramid appearance structure is the weakest, and the etching direction faces the (100) crystal face, so that the tip of the pyramid appearance structure is preferentially etched and flattened, and the quadrangular frustum appearance structure is finally obtained, wherein the side length of the bottom surface of the quadrangular frustum appearance structure is kept constant and still 1-5 micrometers, the height after flattening is 0.3-3 micrometers, the top surface of the quadrangular frustum appearance structure is a plane, and the side length of the top surface is 0.3-3 micrometers. The back of the monocrystalline silicon piece is not completely flat, the anti-reflection structure is arranged, light absorption of a back battery is improved, namely short-circuit current is improved, the efficiency of the back battery is finally improved, and the double-sided rate is improved. In addition, the etching liquid adopted in the etching method for the back structure of the double-sided PERC solar cell has reasonable formula and no nitrogen, thereby effectively avoiding HF/HNO3The emission of nitrogen in the mixed acid etching liquid has low waste liquid treatment cost and small environmental protection pressure, reduces the production cost and simultaneously reduces the pollution to the environment.
The above examples are only preferred embodiments of the present invention, and the present invention is not limited to all embodiments, and any technical solution using one of the above examples or equivalent changes made according to the above examples is within the scope of the present invention.
Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. In addition, although specific terms are used herein, they are used for convenience of description and are not to be construed as limiting the present invention in any way, and other methods similar or equivalent thereto are also within the scope of the present invention.
Claims (10)
1. A back structure etching method of a double-sided PERC solar cell is characterized by comprising the following steps:
(1) preparing a diffused crystal silicon wafer, wherein the back surface of the crystal silicon wafer is provided with a pyramid appearance structure, the bottom side of the pyramid appearance structure is 1-5 microns, and the height of the pyramid appearance structure is 0.7-3.5 microns;
(2) preparing an etching solution: mixing a fluoride ion source, a chloride ion source, an oxidant and deionized water to obtain etching liquid, wherein the concentration of the fluoride ion source is 0.1-8 mol/L, the concentration of the chloride ion source is 0.01-13 mol/L, and the concentration of the oxidant is 0.01-3 mol/L;
(3) back etching: the method comprises the following steps of putting a crystal silicon wafer on a conveying device, conveying the crystal silicon wafer forwards by the conveying device, immersing the back of the crystal silicon wafer into etching liquid, etching the crystal silicon wafer at the temperature of 8-40 ℃ for 30-180 s, and etching and flattening the pyramid tip of the pyramid appearance structure on the back of the crystal silicon wafer to form a quadrangular frustum appearance structure, wherein the side length of the bottom surface of the quadrangular frustum appearance structure is 1-5 micrometers, the side length of the top surface of the quadrangular frustum appearance structure is 0.3-3 micrometers, and the height of the quadrangular frustum appearance structure is 0.3-3 micrometers; the top surface of the quadrangular frustum pyramid morphology structure is a plane, and passivation is easy.
2. The method of claim 1, wherein the silicon wafer is a P-type silicon wafer or an N-type silicon wafer.
3. The method of claim 1, wherein the fluoride ion source is selected from hydrofluoric acid.
4. The method of claim 1, wherein the source of chlorine-containing ions is selected from the group consisting of hydrochloric acid, sodium hypochlorite, sodium chlorite, chlorine dioxide, chlorine gas, sodium chlorate, and sodium perchlorate.
5. The method of claim 1, wherein the oxidant is selected from one or more of sodium persulfate, hydrogen peroxide, acetic acid, peracetic acid, potassium permanganate, and concentrated sulfuric acid.
6. The method of claim 1, wherein the conveyor device is a chain device.
7. The method for etching the back structure of the double-sided PERC solar cell as claimed in any one of claims 1 to 6, wherein an additive is further added in the step (2), and the mass ratio of the additive to the etching solution is 0.2-5: 100.
8. The method for etching the back structure of the double-sided PERC solar cell according to claim 7, wherein the additive comprises the following components in parts by mass: 0.1-5 parts by mass of sodium dodecyl sulfate, 1-3 parts by mass of sodium citrate, 0.5-3 parts by mass of guar gum and 100 parts by mass of water.
9. The method of claim 7, wherein the additive is one or more of sodium dodecyl benzene sulfonate, sodium citrate, and guar gum.
10. An etching solution used in the method for etching a back structure of a bifacial PERC solar cell of any of claims 1-9.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115377252A (en) * | 2022-10-24 | 2022-11-22 | 英利能源发展(天津)有限公司 | A method for suppressing film explosion on the surface of polysilicon grown by PECVD |
| CN118813262A (en) * | 2024-06-18 | 2024-10-22 | 环晟光伏(江苏)有限公司 | Etching liquid for borosilicate glass layer of silicon wafer, use method and application |
| US12191411B2 (en) | 2022-06-21 | 2025-01-07 | Zhejiang Jinko Solar Co., Ltd. | Semiconductor substrate, solar cell, and photovoltaic module |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101468406B1 (en) * | 2013-06-17 | 2014-12-04 | 주식회사 위즈켐 | Etching composition for texturing mono-crystalline silicon wafer of solar cell and texturing method using the same |
| WO2015113890A2 (en) * | 2014-01-31 | 2015-08-06 | Technische Universität Bergakademie Freiberg | Method for producing textures or polishes on the surface of monocrystalline silicon wafers |
| CN106159094A (en) * | 2016-07-04 | 2016-11-23 | 陕西煤业化工技术研究院有限责任公司 | A kind of perovskite solar cell based on silica-based micro-nano structure and preparation method thereof |
| KR20180115119A (en) * | 2017-04-12 | 2018-10-22 | 주성엔지니어링(주) | Method of manufacturing Solar Cell |
-
2020
- 2020-09-16 CN CN202010974812.1A patent/CN114267580A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101468406B1 (en) * | 2013-06-17 | 2014-12-04 | 주식회사 위즈켐 | Etching composition for texturing mono-crystalline silicon wafer of solar cell and texturing method using the same |
| WO2015113890A2 (en) * | 2014-01-31 | 2015-08-06 | Technische Universität Bergakademie Freiberg | Method for producing textures or polishes on the surface of monocrystalline silicon wafers |
| CN106159094A (en) * | 2016-07-04 | 2016-11-23 | 陕西煤业化工技术研究院有限责任公司 | A kind of perovskite solar cell based on silica-based micro-nano structure and preparation method thereof |
| KR20180115119A (en) * | 2017-04-12 | 2018-10-22 | 주성엔지니어링(주) | Method of manufacturing Solar Cell |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US12191411B2 (en) | 2022-06-21 | 2025-01-07 | Zhejiang Jinko Solar Co., Ltd. | Semiconductor substrate, solar cell, and photovoltaic module |
| CN115377252A (en) * | 2022-10-24 | 2022-11-22 | 英利能源发展(天津)有限公司 | A method for suppressing film explosion on the surface of polysilicon grown by PECVD |
| CN118813262A (en) * | 2024-06-18 | 2024-10-22 | 环晟光伏(江苏)有限公司 | Etching liquid for borosilicate glass layer of silicon wafer, use method and application |
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