CN105932076A - Photovoltaic cell and preparation method thereof - Google Patents

Abstract

The invention provides a photovoltaic cell, which is characterized in comprising a back electrode, a back electric field, a P-type substrate, a reaction ion etching texture layer, a PN node layer, an antireflection film layer and a grid line electrode, wherein the back electrode, the back electric field, the P-type substrate, the reaction ion etching texture layer, the PN node layer, the antireflection film layer and the grid line electrode are successively arranged from bottom to top; one surface, which is in contact with the antireflection film layer, of the PN node layer is provided with a plurality of parallel grooves; and the PN node layer and the antireflection film layer are in continuous contact. Compared with the prior art, the photovoltaic cell firstly utilizes reactive ion etching to change a battery texture structure and improve the adsorption rate of photons, and a battery conversion effect is improved through the reduction of the incident light loss of the battery; secondly, laser grooving is carried out after the PN node layer is formed through diffusion on the optimized surface of the optimized battery, the battery morphology obtained after grooving can more effectively enhance adsorption on sunlight, a battery grid line and the optimized battery texture can better form Ohmic contact since a photon refraction process is added, so that the collection and the output of photon-generated carriers can be improved so as to improve the short circuit current and the open circuit voltage of the battery.

Description

A kind of photovoltaic cell and preparation method thereof

technical field

The invention belongs to the technical field of batteries, and in particular relates to a photovoltaic battery and a preparation method thereof.

Background technique

Solar energy is one of the energy sources developed at home and abroad. It uses photovoltaic cells to absorb the sun's light energy and convert it into electrical energy. It has great potential and prospects to replace traditional energy sources. Among various solar cells, silicon-based solar cells account for 90% of the total market share. However, high production cost and low efficiency have always been the factors that plague the development of silicon-based batteries, which are still far from traditional petrochemical energy sources. Therefore, improving the conversion efficiency of solar cells and reducing production costs are huge challenges we face. Among them, improving the textured structure of solar cells and improving the conversion efficiency of the cells is also an effective way to reduce costs.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a photovoltaic cell and a preparation method thereof, and the conversion efficiency of the photovoltaic cell is relatively high.

The invention provides a photovoltaic cell, which includes: a back electrode, a back electric field, a P-type substrate, a reactive ion etching suede layer, a PN junction layer, an anti-reflection film layer, and a grid wire electrode arranged in sequence from bottom to top; The side of the PN junction layer in contact with the anti-reflection film layer is provided with a plurality of parallel grooves; the PN junction layer is in continuous contact with the anti-reflection film layer.

Preferably, the thickness of the reactive ion etching textured layer is to control the reflectivity of 4% to 10%.

Preferably, a texture layer formed by cleaning texture is also included between the P-type substrate and the reactive ion etching texture layer.

Preferably, the pore size of the reactive ion etching textured layer is 200-500 μm.

Preferably, the depth of the PN junction layer is 0.2-0.5 μm.

Preferably, the width of the groove is 40-100 μm.

Preferably, the depth of the groove is 0.5-1 μm.

Preferably, the gate electrode includes a main gate electrode and a fine gate electrode perpendicular to each other; the main gate electrode is parallel to the groove opened in the PN junction layer.

Preferably, the gate electrode includes a main gate electrode and a fine gate electrode perpendicular to each other; the fine gate electrode is parallel to the groove opened in the PN junction layer.

The present invention also provides a method for preparing a photovoltaic cell, comprising:

performing reactive ion etching on one side of the P-type substrate to obtain a reactive ion etching textured layer;

Diffusion is carried out in the reactive ion etching textured layer to form a PN junction layer;

Grooving is performed on the surface of the PN junction layer, and then coating is performed to form an anti-reflection film layer;

Printing electrode paste on the surface of the anti-reflection film layer to form grid line electrodes;

The back electrode paste is printed on the surface opposite to the contact surface of the P-type substrate and the reactive ion etching texture layer to form a back electric field and a back electrode.

The invention provides a photovoltaic cell, which is characterized in that it includes: a back electrode, a back electric field, a P-type substrate, a reactive ion etching texture layer, a PN junction layer, an anti-reflection film layer and a gate Wire electrodes; the side of the PN junction layer in contact with the anti-reflection film layer is provided with a plurality of parallel grooves; the PN junction layer is in continuous contact with the anti-reflection film layer. Compared with the prior art, the present invention first uses reactive ion etching to change the textured structure of the battery, enhance the absorption of sunlight, and increase the absorption rate of photons, thereby improving the conversion effect of the battery by reducing the incident light loss of the battery , secondly, laser slotting is performed after the optimized cell surface is diffused to form a PN junction layer, and the surface area of the battery continues to increase. The cell morphology after slotting can effectively enhance the absorption of sunlight and increase the photon density. The refracted optical path is used to pave the way for subsequent printed grid lines. The purpose is to better form ohmic contact between the battery grid lines and the optimized battery suede surface, so as to improve the collection and output of photogenerated carriers, thereby improving The short-circuit current and open-circuit voltage of the battery improve the conversion efficiency of the battery and are suitable for mass production.

Description of drawings

Fig. 1 is a schematic structural diagram of a photovoltaic cell provided by the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a photovoltaic cell, which includes: a back electrode, a back electric field, a P-type substrate, a reactive ion etching suede layer, a PN junction layer, an anti-reflection film layer, and a grid wire electrode arranged in sequence from bottom to top; The side where the PN junction layer is in contact with the anti-reflection film layer is provided with a plurality of parallel grooves; the continuous contact between the PN junction layer and the anti-reflection film layer; the structural representation of the photovoltaic cell is as shown in Figure 1, wherein A is the P-type substrate, B is the reactive ion etching texture layer, C is the PN junction layer, D is the reflective film layer, E is the fine grid electrode, F is the main grid electrode, G is the back electric field, and H is the back electrode.

Wherein, the back electrode and the back electric field can be the back electrode and the back electric field well-known to those skilled in the art, and there is no special limitation. In the present invention, the back electrode and the back electric field are preferably formed by silver-aluminum paste.

The P-type substrate can be a P-type substrate well known to those skilled in the art, and there is no special limitation.

The surface of the P-type substrate that is in contact with the back electric field is preferably provided with a suede layer formed by cleaning and texturing. The method for cleaning the texture is a method well known to those skilled in the art, and there is no special limitation.

A reactive ion etching textured layer is provided on the side of the textured layer that is not in contact with the P-type substrate; the thickness of the reactive ion etched textured layer is preferably to control the reflectivity of its surface to 4% to 10%, It is more preferably 6%-8%; the surface of the reactive ion etching textured layer has a porous structure, and its pore size is preferably 200-500 μm, more preferably 300-400 μm.

The surface of the reactive ion etching suede layer is provided with a PN junction layer; the depth of the PN junction layer is preferably 0.2-0.5 μm, more preferably 0.3-0.4 μm, most preferably 0.35 μm; the PN junction layer The surface square resistance is preferably 90-130Ω, more preferably 90-120Ω, still more preferably 100-120Ω, and most preferably 110Ω.

The surface of the PN junction layer is provided with a plurality of parallel grooves; the width of the grooves is preferably 40-100 μm, more preferably 50-90 μm, and more preferably 60-80 μm; the depth of the grooves is preferably 0.5-1 μm ,, more preferably 0.3-0.66 μm; the length of the groove preferably runs through the entire surface of the PN junction layer, that is, the length of the groove is the same as the length of the P-type substrate.

In the present invention, the surface of the PN junction layer is provided with an anti-reflection film layer in continuous contact; Preferably, it is a SiN layer; the thickness of the anti-reflection coating layer is preferably 78-85 μm, more preferably 78-84 μm, and more preferably 78-82 μm; the refractive index of the anti-reflection coating layer is preferably 1.5-3, more preferably Preferably it is 1.6-2.8, More preferably, it is 1.6-2.6.

A grid line electrode is arranged on the anti-reflection film layer; the grid line electrode preferably includes a main grid electrode and a fine grid electrode perpendicular to each other; the main grid electrode can be parallel to the groove opened in the PN junction layer, or The fine gate electrode is parallel to the groove opened in the PN junction layer. The position of the grid line electrode matches the slot, which can increase the number of collected carriers and enhance the ohmic contact between the battery electrode and the P-type substrate.

The present invention first uses reactive ion etching to change the textured structure of the battery, enhances the absorption of sunlight, and increases the absorption rate of photons, thereby improving the conversion effect of the battery by reducing the incident light loss of the battery. After the PN junction layer is diffused on the suede surface of the battery, laser grooves are performed to continue to increase the surface area of the battery. The shape of the battery after grooves can more effectively enhance the absorption of sunlight and increase the refracted optical path of photons, which will provide future The purpose of printing the grid line as a pad is to make the battery grid line and the optimized battery suede better form ohmic contact, so as to improve the collection and output of photogenerated carriers, thereby increasing the short-circuit current (Isc) of the battery And open circuit voltage (Uoc), thereby improving the conversion efficiency of the battery, and suitable for mass production.

The present invention also provides a method for preparing the above-mentioned photovoltaic cell, comprising:

performing reactive ion etching on one side of the P-type substrate to obtain a reactive ion etching textured layer;

Diffusion is carried out in the reactive ion etching textured layer to form a PN junction layer;

Grooving is performed on the surface of the PN junction layer, and then coating is performed to form an anti-reflection film layer;

Printing electrode paste on the surface of the anti-reflection film layer to form grid line electrodes;

The back electrode paste is printed on the surface opposite to the contact surface of the P-type substrate and the reactive ion etching texture layer to form a back electric field and a back electrode.

Wherein, the P-type substrate, the reactive ion etching texture layer, the PN junction layer, the anti-reflection film layer, the grid line electrode, the back electric field and the back electrode are all the same as above, and will not be repeated here.

According to the present invention, it is preferable to firstly wash and texture one side of the P-type substrate to remove the loss layer and impurities of the original sheet itself to form a textured layer; wherein, the thinning amount of the cleaning texture is preferably 0.25-0.35 g.

Then carry out reactive ion etching on the surface of the textured layer to form a reactive ion etched textured layer; the reactive ion etching is preferably carried out in reactive ion etching equipment, wherein the flow rate of chlorine is preferably 400 to 1200 sccm, and the flow rate of oxygen The flow rate is preferably 900-2000 sccm, the input flow rate of sulfur hexafluoride is preferably 600-700 sccm, and the output flow rate of sulfur hexafluoride is preferably 500-650 sccm; the reaction time of the reactive ion etching is preferably 3-5s; the reaction pressure Preferably 20-30Pa, more preferably 22-26Pa, more preferably 23-25Pa, most preferably 24Pa; the power of the reactive ion etching equipment is preferably 1000-2000W, more preferably 1000-1500W, and more preferably 1000-1200W, most preferably 1000W. After reactive ion etching, the cell was black.

Then, the P-type substrate after reactive ion etching is preferably cleaned and repaired. The cleaning process is a cleaning process well known to those skilled in the art, and there is no special limitation. In the present invention, the following steps are preferably used for cleaning and repairing : carry out successively HF pickling, deionized water washing, alkali washing, deionized water washing, HF+HNO ₃ +DI water mixed pickling, deionized water (DI) washing, deionized water washing after heating, drying; the HF acid The mass concentration of the HF solution in washing is preferably 50% to 60%, more preferably 54% to 58%, most preferably 56%; the time of the HF pickling is preferably 100 to 150s, more preferably 100 to 130s, It is more preferably 110～130s, most preferably 120s; the time of the deionized water washing is preferably 100～300s, more preferably 200～300s; the alkali washing preferably uses KOH solution for alkali washing; the time of the alkali washing Preferably it is 10-50s, more preferably 15-40s, more preferably 15-30s, most preferably 15-25s; in some embodiments provided by the present invention, the time for the alkali washing is preferably 20s; the HF In the mixed pickling of +HNO ₃ +DI water, the mass ratio of HF:HNO ₃ :DI is preferably 1:(1-6):6, more preferably 1:2:6.

After cleaning and repairing, diffusion junction is performed to form a PN junction layer.

Then groove, preferably laser groove, is performed on the surface of the PN junction layer; the width and depth of the groove are the same as those described above, and will not be repeated here.

After slotting, it is preferable to carry out etching cleaning to remove the phosphosilicate glass on the edge and trim the debris and damaged parts left on the surface of the battery after the slotting; after etching cleaning, it is preferable to carry out oxidation passivation, and it is more preferable to use ozone for oxidation Passivation; In the present invention, it is preferred to etch and clean with the etching blanking equipment, and an ozone generator is installed at the etching blanking end, and the battery through the ozone generator has a strong passivation effect, which can improve the resistance of the battery itself. decline ability.

After the above steps are processed, the surface of the PN junction layer is coated to form an anti-reflection film layer; the anti-reflection film layer _is preferably a Six _Ny anti-reflection film layer; the method of the coating film is well known to those skilled in the art The method can be used without any special restrictions.

Finally, the electrode paste is printed on the surface of the anti-reflection film layer to form a grid line electrode; the back electrode paste is printed on the opposite surface of the P-type substrate and the contact surface of the reactive ion etching suede layer to form a back electric field and a back electrode. electrode. The present invention has no special limitation on these two steps, the grid line electrode can be prepared first, and the back electric field and the back electrode can also be prepared first.

In order to further illustrate the present invention, a photovoltaic cell provided by the present invention and its preparation method are described in detail below in conjunction with examples.

The reagents used in the following examples are all commercially available.

Example 1

1.1 Choose 156x156mm polysilicon wafers, the thickness of which is within the range of 210±10μm; clean the silicon wafers before making texture, remove the loss layer and impurities of the original sheet itself, and form a texture layer; the thinning amount is controlled between 0.25 ~ 0.35g .

1.2 Put the multi-wafer prepared above into the RIE equipment for reactive ion dry etching to form a reactive ion etching texture layer with a circular hole diameter of 200-500 μm, in which the flow rate of Cl ₂ gas is controlled at 400-500 μm Between 1200sccm; the flow rate of O ₂ gas is controlled between 900-2000sccm; the input and output flow rates of SF ₆ gas are between 600-700sccm and 500-650sccm respectively, the reaction time is 3-5s, the reaction pressure is 24pa, the power The range is between 1000 and 2000W; the battery made is black.

1.3 Put the multi-wafer that has been dry-etched into the cleaning equipment for repair. The process is first HF pickling for 120s-deionized water washing for 100-300s-KOH alkali washing for 10-50s-deionized water washing-HF+HNO ₃ mixed solution washing - Deionized water washing - deionized water washing for 60s after heating - drying; wherein the mass concentration of HF acid is 56%, and the mass ratio of HF acid, _HNO3 acid and water in the mixed solution is 1:2:6.

1.4 Diffusion and junction formation are performed on the surface of the reactive ion etching suede layer of the repaired battery to form a PN junction layer, and its surface square resistance ranges from 90 to 130Ω.

1.5 Carry out laser grooves on the surface of the PN junction layer of the above-mentioned diffused polycrystalline silicon wafer, the groove line length is 156 mm, and the line width range is between 50 and 90 μm.

1.6 Etch and clean the above-mentioned multi-wafer with grooves, remove the phosphosilicate glass on the edge and trim the debris and damaged parts left on the surface of the battery after the groove; secondly, an O3 generator is installed at the end of the etching and feeding process. The battery of the O3 generator has a strong passivation effect, which can improve the anti-aging ability of the battery itself.

1.7 Coating the multi-wafer with grooves above to form a Six _Ny anti-reflection film with a thickness range of 80± _2nm and a refractive index of 2.10±0.5.

1.8 Print silver-aluminum paste on the back of the above-mentioned coated multi-chip, that is, the other side of the P-type substrate, to form a back electrode and a back electric field.

1.9 Print silver paste on the surface of the above-mentioned coated multi-chip, that is, the surface of the Six _Ny anti-reflection film. The screen pattern used in the printing process _is parallel to the line size after the battery surface is grooved, and finally the positive electrode is formed by printing. Vertical main gate electrodes and fine gate electrodes.

Example 2

2.1 Select 156x156mm polysilicon wafers, the thickness of which is within the range of 210±10μm; the silicon wafers are pre-cleaned and textured to remove the loss layer and impurities of the original wafer itself to form a textured layer; the thinning amount is 0.25g.

2.2 Put the prepared multi-wafer into the RIE equipment for reactive ion dry etching to form a reactive ion etching texture layer with a circular hole diameter of 200-500 μm, wherein the flow rate of Cl ₂ gas is 400 sccm, The outflow is between 1200sccm; the flow control of O ₂ gas is 900sccm; the input and output flow rates of SF ₆ gas are between 600-700sccm and 500-650sccm respectively, the reaction time is 3sec, the reaction pressure is 24pa, and the power range is between 1000W The battery made is black; the reflectance measured after the process is 9%.

2.3 Put the dry-etched multi-wafer into the cleaning equipment for repair. The process is first HF pickling for 120s-deionized water washing for 100-300s-KOH alkali washing for 50s-deionized water washing-HF+HNO ₃ mixed solution washing-removal Ionized water washing - deionized water washing for 60s after heating - drying; the mass concentration of HF acid is 56%, and the mass ratio of HF acid, _HNO3 acid and water in the mixed solution is 1:2:6; the reflectance after washing 10%.

2.4 Diffusion and junction formation are performed on the surface of the reactive ion etching texture layer of the repaired battery to form a PN junction layer with a surface square resistance range of 110Ω.

2.5 Carry out laser grooves on the surface of the PN junction layer of the above-mentioned diffused polycrystalline silicon wafer, the groove line length is 156 mm, and the line width is 50 μm.

2.6 Etch and clean the above-mentioned multi-wafers with grooves, remove the phosphosilicate glass on the edge and trim the debris and damaged parts left on the surface of the battery after the grooves; secondly, an _O3 generator is installed at the etching and feeding end, The battery passed through the O ₃ generator has a strong passivation effect, which can improve the anti-aging ability of the battery itself.

2.7 Coating the grooved multi-wafers above to form a _{Six Ny anti} -reflection film with a film thickness of 80 nm and a refractive index of 2.10±0.5.

2.8 Print silver-aluminum paste on the back of the above-mentioned coated multi-chip, that is, the other side of the P-type substrate, to form a back electrode and a back electric field.

2.9 Print silver paste on the surface of the above-mentioned multi-chip coated film, that is, the surface of the Six _Ny anti-reflection film. The screen pattern used in the printing process _is parallel to the line size after the battery surface is grooved, and finally the positive electrode is formed by printing. Vertical main gate electrodes and fine gate electrodes.

The photovoltaic cell obtained in Example 2 is tested, and its test efficiency can reach 19%.

Example 3

3.1 Choose 156x156mm polysilicon wafers, the thickness of which is within the range of 200±10μm; wash and texture the silicon wafers before removing the loss layer and impurities of the original wafer itself to form a textured layer; the thinning amount is 0.25g.

3.2 Put the multi-wafer prepared above into the RIE equipment for reactive ion dry etching to form a reactive ion etching texture layer with a circular hole diameter of 200-500 μm, wherein the flow rate of Cl ₂ gas is 300 sccm, The outflow is between 1100sccm; the flow control of _O2 gas is 900sccm; the input and output flow rates of _SF6 gas are between 600-700sccm and 500-650sccm respectively, the reaction time is 3sec, the reaction pressure is 24pa, and the power range is between 1000W The battery made is black; the reflectance measured after the process is 7%.

3.3 Put the dry-etched multi-chip into the cleaning equipment for repair, the process is first HF pickling for 120s-deionized water washing for 100-300s-KOH alkali washing for 30s-deionized water washing-HF+HNO ₃ mixed solution washing-removal Ionized water washing - deionized water washing for 60s after heating - drying; the mass concentration of HF acid is 56%, and the mass ratio of HF acid, _HNO3 acid and water in the mixed solution is 1:2:6; the reflectance after washing 9%.

3.4 Diffusion and junction formation are performed on the surface of the reactive ion etching fleece layer of the repaired battery to form a PN junction layer with a surface square resistance range of 110Ω.

3.5 Carry out laser grooving on the surface of the PN junction layer of the above-mentioned diffused polycrystalline silicon wafer, the grooving line length is 156 mm, and the line width is 50 μm.

3.6 Etch and clean the above-mentioned multi-wafer with grooves, remove the phosphosilicate glass on the edge and trim the debris and damaged parts left on the surface of the battery after the groove; secondly, an _O3 generator is installed at the end of the etching, The battery passed through the O ₃ generator has a strong passivation effect, which can improve the anti-aging ability of the battery itself.

3.7 Coating the grooved multi-wafers to form a _{Six Ny anti} -reflection film with a film thickness of 80 nm and a refractive index of 2.10±0.5.

3.8 Print silver-aluminum paste on the back of the above-mentioned coated multi-chip, that is, the other side of the P-type substrate, to form a back electrode and a back electric field.

3.9 Print silver paste on the surface of the above-mentioned coated multi-chip, that is, the surface of the Six _Ny anti-reflection film. The screen pattern used in the printing process _is parallel to the line size after the battery surface is grooved, and finally the positive electrode is formed by printing. Vertical main gate electrodes and fine gate electrodes.

The photovoltaic cell obtained in Example 3 is tested, and its test efficiency can reach 19%.

Example 4

4.1 Choose 156x156mm polysilicon wafers, the thickness of which is within the range of 190±10μm; wash and texture the silicon wafers before removing the loss layer and impurities of the original wafer itself to form a textured layer; the thinning amount is 0.25g.

4.2 Put the multi-wafer prepared above into the RIE equipment for reactive ion dry etching to form a reactive ion etching texture layer with a circular hole diameter of 200-500 μm, wherein the flow rate of Cl ₂ gas is 200 sccm, The outflow is between 1000sccm; the flow control of _O2 gas is 900sccm; the input and output flow rates of _SF6 gas are between 600-700sccm and 500-650sccm respectively, the reaction time is 3sec, the reaction pressure is 24pa, and the power range is between 1000W The battery made is black; the reflectance measured after the process is 6%.

4.3 Put the dry-etched multi-chip into the cleaning equipment for repair, the process is first HF pickling for 120s-deionized water washing for 100-300s-KOH alkali washing for 20s-deionized water washing-HF+HNO ₃ mixed solution washing-removal Ionized water washing - deionized water washing for 60s after heating - drying; the mass concentration of HF acid is 56%, and the mass ratio of HF acid, _HNO3 acid and water in the mixed solution is 1:2:6; the reflectance after washing 8%.

4.4 Diffusion and junction formation are performed on the surface of the reactive ion etching texture layer of the repaired battery to form a PN junction layer with a surface square resistance range of 110Ω.

4.5 Carry out laser grooves on the surface of the PN junction layer of the above-mentioned diffused polycrystalline silicon wafer, the groove line length is 156 mm, and the line width is 50 μm.

4.6 Etch and clean the above-mentioned multi-wafers with grooves, remove the phosphosilicate glass on the edge and trim the debris and damaged parts left on the surface of the battery after the grooves; secondly, an _O3 generator is installed at the end of the etching, The battery passed through the O ₃ generator has a strong passivation effect, which can improve the anti-aging ability of the battery itself.

4.7 Coating the grooved multi-wafers above to form a _{Six Ny anti} -reflection film with a film thickness of 80 nm and a refractive index of 2.10±0.5.

4.8 Print silver-aluminum paste on the back of the above-mentioned coated multi-chip, that is, the other side of the P-type substrate, to form a back electrode and a back electric field.

4.9 Print silver paste on the surface of the above-mentioned coated multi-chip, that is, the surface of the Six _Ny anti-reflection film. The screen pattern used in the printing process _is parallel to the line size after the battery surface is grooved, and finally the positive electrode is formed by printing. Vertical main gate electrodes and fine gate electrodes.

The photovoltaic cell obtained in Example 4 is tested, and its test efficiency can reach 19%.

Claims (10)

1. A photovoltaic cell, characterized in that it comprises sequentially arranged from bottom to top: back electrode, back electric field, P-type substrate, reactive ion etching suede layer, PN junction layer, anti-reflection film layer and grid wire electrode ; The side of the PN junction layer in contact with the anti-reflection film layer is provided with a plurality of parallel grooves; the continuous contact between the PN junction layer and the anti-reflection film layer. 2 . The photovoltaic cell according to claim 1 , wherein the thickness of the reactive ion etching textured layer is to control the reflectivity of 4% to 10%. 3 . 3 . The photovoltaic cell according to claim 1 , wherein a texture layer formed by cleaning texture is also included between the P-type substrate and the reactive ion etching texture layer. 4 . 4. The photovoltaic cell according to claim 1, characterized in that the pore size of the reactive ion etching textured layer is 200-500 μm. 5. The photovoltaic cell according to claim 1, characterized in that, the depth of the PN junction layer is 0.2-0.5 μm. 6 . The photovoltaic cell according to claim 1 , wherein the groove has a width of 40-100 μm. 7 . The photovoltaic cell according to claim 1 , wherein the depth of the groove is 0.5˜1 μm. 8 . The photovoltaic cell according to claim 1 , wherein the gate electrode comprises a main gate electrode and a fine gate electrode perpendicular to each other; the main gate electrode is parallel to the groove opened in the PN junction layer. 9 . The photovoltaic cell according to claim 1 , wherein the gate electrode comprises a main gate electrode and a fine gate electrode perpendicular to each other; the fine gate electrode is parallel to the groove opened in the PN junction layer. 10. A method for preparing a photovoltaic cell, comprising: performing reactive ion etching on one side of the P-type substrate to obtain a reactive ion etching textured layer; Diffusion is carried out in the reactive ion etching textured layer to form a PN junction layer; Grooving is performed on the surface of the PN junction layer, and then coating is performed to form an anti-reflection film layer; Printing electrode paste on the surface of the anti-reflection film layer to form grid line electrodes; The back electrode paste is printed on the surface opposite to the contact surface of the P-type substrate and the reactive ion etching texture layer to form a back electric field and a back electrode.