CN105742408A - Metalizing method for N type double-sided solar cell, cell, assembly and system - Google Patents

Abstract

The invention relates to a metallization method of an N-type double-sided solar cell, the cell, a component, and a system. A metallization method for an N-type double-sided solar cell of the present invention, for an N-type double-sided solar cell in which the p+ doped region and the n+ doped region are respectively arranged on the front surface and the back surface of a silicon wafer and surface passivation is completed, Its metallization process is to print metal paste first to form a metal main gate electrode in contact with the front and rear surfaces of the silicon wafer and then dry it, but the main gate electrode does not form an ohmic pattern with the p+ doped region and n+ doped region on the front and rear surfaces of the silicon wafer. Then paste the metal wires coated with aluminum-doped silver paste and silver paste on the front and rear surfaces of the silicon wafer respectively, and form ohmic contact with the p+ doped region and n+ doped region after drying and sintering, thus forming a fine grid Wire electrodes, to complete the metallization of the battery. The beneficial effect is that the method increases the open-circuit voltage of the N-type double-sided solar cell, greatly reduces the consumption of silver paste of the cell, thereby reducing the production cost of the cell sheet.

Description

Metallization method of N-type double-sided solar cell, cell, component, and system

technical field

The invention relates to the technical field of solar cells, in particular to a metallization method of an N-type double-sided solar cell, a cell, a component, and a system.

Background technique

A solar cell is a semiconductor device that converts light energy into electrical energy. Its low production cost and high energy conversion efficiency have always been the goal pursued by the solar cell industry. The n-type solar cell has no light attenuation and long service life. The advantage is that it is an important development direction of high-efficiency crystalline silicon solar cells, and since the positive and negative electrodes of n-type solar cells can be made into conventional H-shaped grid electrode structures, not only the front side of the cell can absorb light, but the back surface can also absorb light. It can absorb reflected and scattered light to generate additional electricity, realizing double-sided power generation.

However, the manufacturing cost of N-type batteries is about 15% higher than that of conventional batteries, which is mainly due to the printing of silver paste on both sides of the battery, and the silver consumption is twice that of conventional batteries. The increase is about 10%, therefore, reducing the silver paste consumption of the battery is the key to reducing the cost of the battery.

Contents of the invention

The object of the present invention is to provide a metallization method for N-type double-sided solar cells, cells, components, and systems to address the deficiencies in the prior art. The metallization method of the solar cell can significantly reduce the usage amount of the silver-containing paste, thereby reducing the production cost of the solar cell.

The present invention also provides a metallization method for an N-type double-sided solar cell, the technical solution of which is:

A metallization method for an N-type double-sided solar cell, comprising the following steps:

(1), prepare a p+ doped region and an n+ doped region on the front surface and the back surface of the N-type crystalline silicon substrate, and prepare a passivation anti-reflection film on the front surface, and prepare a passivation film on the back surface;

(2) Print metal paste on the front surface and the back surface of the N-type crystalline silicon substrate and dry to form the front metal busbar electrode and the back metal busbar electrode, the front metal busbar electrode and the p+ doped region No ohmic contact is formed, and the back metal main gate electrode does not form an ohmic contact with the n+ doped region;

(3), paste the metal wire with aluminum-doped silver paste on the front surface of the N-type crystalline silicon substrate, paste the metal wire with the silver paste on the back surface of the N-type crystalline silicon substrate, after drying, After sintering, the silver aluminum alloy formed by the metal wire through the sintered aluminum-doped silver paste and the silver formed by the sintering of the silver paste form ohmic contacts with the p+ doped region and the n+ doped region respectively, and the metal wire and the main The gate electrode also forms an ohmic contact to complete the metallization of the solar cell.

Wherein, the passivation antireflection film is one or more of SiO2 dielectric film, SiNx dielectric film or Al2O3 dielectric film, and the passivation film is a composite dielectric film composed of SiO2 dielectric film and SiNx dielectric film.

Among them, the thickness of the N-type crystalline silicon substrate is 50-300 μm; the doping depth of the p+ doped region is 0.5-2.0 μm; the thickness of the passivation anti-reflection film is 70-110 nm; the thickness of the passivation film is not less than 20 nm ; The doping depth of the n+ doped region is 0.5-2.0 μm.

Wherein, the number of the front metal busbar electrodes and the back metal busbar electrodes is more than two, and the positions of the front metal busbar electrodes and the rear metal busbar electrodes correspond to each other, and are evenly distributed on the N-type crystalline silicon substrate. On the surface, the widths of the front metal main grid electrode and the back metal main grid electrode are both 0.5-3mm.

Wherein, the aluminum-doped silver paste adhering to the metal wire or the silver paste is adhering discontinuously or continuously on the metal wire.

Wherein, the cross-sectional shape of the metal wire is circular, square or triangular, and the diameter of the circular metal wire is 40-80um.

Wherein, the method for pasting the metal wire in the step (3) is to paste a plurality of metal wires attached with aluminum-doped silver paste in parallel on the front surface of the silicon chip at equal intervals in a direction perpendicular to the front metal main grid electrode and dry them. The distance between the metal wires on the front surface is 1-3mm; then paste the metal wires coated with silver paste on the back surface of the silicon wafer at equal intervals in parallel to the direction perpendicular to the back metal main grid electrode and dry them. The spacing between the wires is 1-3mm.

Wherein, the sintering temperature in step (3) is not higher than 900 degrees Celsius.

The present invention also provides an N-type double-sided solar cell, which includes an N-type crystalline silicon substrate, and the front surface of the N-type crystalline silicon substrate includes a p+ doped region and a passivation anti-reflection film on the front surface sequentially from the inside to the outside; the N-type The back surface of the crystalline silicon substrate includes an n+ doped region and a passivation film on the back surface sequentially from the inside to the outside, and the front surface of the N-type crystalline silicon substrate includes a front metal busbar electrode and a front metal wire, and the front metal wire is connected to the front metal wire. The p+ doped region is connected by silver-aluminum alloy; the back surface of the N-type crystalline silicon substrate includes a rear metal busbar electrode and a rear metal wire, and the metal wire is connected to the n+ doped region by silver.

Wherein, the passivation antireflection film is one or more of SiO2 dielectric film, SiNx dielectric film or Al2O3 dielectric film, and the passivation film is a composite dielectric film composed of SiO2 dielectric film and SiNx dielectric film; N-type crystal The thickness of the silicon substrate is 50-300 μm; the doping depth of the p+ doped region is 0.5-2.0 μm; the thickness of the passivation anti-reflection film is 70-110nm; the thickness of the passivation film is not less than 20nm; the n+ doped region The doping depth is 0.5-2.0 μm.

Wherein, the number of the front metal busbar electrodes and the back metal busbar electrodes is more than two, and the positions of the front metal busbar electrodes and the rear metal busbar electrodes correspond to each other, and are evenly distributed on the N-type crystalline silicon substrate. On the surface, the widths of the front metal main grid electrode and the back metal main grid electrode are both 0.5-3mm. The aluminum-doped silver paste or the silver paste adhered to the wire is discontinuously adhered to the wire or continuously adhered to the wire. The cross-sectional shape of the metal wire is circular, square or triangular, and the diameter of the circular metal wire is 40-80um.

The present invention also provides an N-type double-sided solar cell module, comprising front layer material, encapsulation material, N-type double-sided solar cell, encapsulation material, and back layer material arranged sequentially from top to bottom, the N-type double-sided The solar cell is a kind of N-type double-sided solar cell mentioned above.

The present invention also provides an N-type double-sided solar cell system, including one or more than one N-type double-sided solar cell components connected in series, and the N-type double-sided solar cell component is the above-mentioned N-type double-sided solar cell battery pack.

Implementation of the present invention comprises following technical effect:

The metallization method of the N-type double-sided solar cell proposed by the present invention is compared with the metallization process of the conventional N-type double-sided solar cell. The difference of the present invention has the following two points: 1. The p+ doped region on the surface forms an ohmic contact with the n+ doped region, which greatly reduces the recombination rate between the metal electrode and silicon, thereby increasing the open circuit voltage of the N-type double-sided solar cell; 2. With the p+ doped region The metal thin grid lines in ohmic contact with the n+ doped region are respectively pasted on the front and rear surfaces of the silicon wafer in the direction perpendicular to the main grid electrode by metal wires coated with aluminum-doped silver paste and silver paste, and then dried and sintered. In this way, the silver paste consumption of the battery is greatly reduced while ensuring that the resistance of the metal fine grid wire does not increase, thereby reducing the production cost of the battery sheet.

Description of drawings

FIG. 1 is a schematic cross-sectional view of a cell structure in Step 1 of a metallization method for an N-type double-sided solar cell according to an embodiment of the present invention.

2 is a schematic cross-sectional view of a cell structure in Step 2 of a metallization method for an N-type double-sided solar cell according to an embodiment of the present invention.

3 is a schematic diagram of a metal wire adhered with aluminum-doped silver paste in a metallization method of an N-type double-sided solar cell according to an embodiment of the present invention.

4 is a schematic diagram of a metal wire adhered with silver paste in a metallization method of an N-type double-sided solar cell according to an embodiment of the present invention.

5 is a schematic cross-sectional view of a cell structure in Step 5 of a metallization method for an N-type double-sided solar cell according to an embodiment of the present invention.

FIG. 6 is a schematic front plan view of a cell structure obtained by a metallization method of an N-type double-sided solar cell according to an embodiment of the present invention.

Fig. 7 is a schematic plan view of the back of the cell structure obtained by the metallization method of an N-type double-sided solar cell according to an embodiment of the present invention.

detailed description

The present invention will be described in detail below in conjunction with the embodiments and the accompanying drawings. It should be noted that the described embodiments are only intended to facilitate the understanding of the present invention, rather than limiting it in any way.

Referring to Figures 1 to 7, the metallization method of the N-type double-sided solar cell in this embodiment includes the following steps:

(1), as shown in Figure 1, prepare the N-type double-sided solar cell before metallization, comprise N-type crystalline silicon substrate 10, the positive surface of N-type crystalline silicon substrate comprises p+ doping region 12 from inside to outside sequentially and a passivation anti-reflection film 14 on the front surface; the back surface of the N-type crystalline silicon substrate includes an n+ doped region 16 and a passivation film 18 on the back surface sequentially from inside to outside. The passivation anti-reflection film 14 on the front surface is one or more of SiO2, SiNx and Al2O3 dielectric films, and the passivation film 18 on the back surface is a composite dielectric film composed of SiO2 or SiNx dielectric films. The thickness of the N-type crystalline silicon substrate 10 is 50-300 μm; the doping depth of the p+ doped region 12 is 0.5-2.0 μm; the thickness of the passivation anti-reflection film on the front surface is 70-110 nm; the thickness of the passivation film 18 on the back surface The doping depth of the n+ doped region 16 is not less than 20 nm; the doping depth of the n+ doped region 16 is 0.5-2.0 μm.

(2), as shown in Figure 2, by printing the metal paste and drying to form the front metal busbar electrode 20 and the back metal busbar electrode 22 in contact with the front and back surfaces of the silicon wafer, the front metal busbar electrode 20 and the back metal busbar electrode The metal paste used for the main gate electrode 22 does not burn through the passivation films on the front and rear surfaces of the silicon wafer, that is, the front metal main gate electrode 20 and the back metal main gate electrode 22 are in contact with the p+ doped region 12 on the front surface of the silicon wafer and the n+ doped region on the back surface. The impurity region 16 does not form an ohmic contact. The number of busbar electrodes on the front and rear surfaces of the silicon wafer is required to be greater than 2, and the busbar electrodes on the front and rear surfaces of the silicon wafer are required to correspond one-to-one, and the positions are the same and evenly distributed on the surface of the silicon wafer. The width is 0.5-3mm.

(3), as shown in Figure 3, the aluminum-doped silver paste 24 that can form ohmic contact with the p+ doped region 12 of the N-type double-sided battery is coated on one side of the front surface wire 26, and adheres to the front surface wire The aluminum-doped silver paste on the 26 can be adhered discontinuously on the wire, or can be continuously attached on the wire; the cross section of the front surface metal wire 26 can be circular, and its diameter is 40-80um; The cross-sectional shape of the metal wire 26 can also be square or triangular. The metal wire may be copper wire or silver-clad copper wire.

(4), as shown in Figure 4, the silver paste 30 that can form ohmic contact with N-type double-sided battery n+doped region 16 is coated on the side of back surface wire 28, is coated on the side of back surface wire 28 The silver paste can be adhered discontinuously on the wire or continuously; the cross section of the back surface metal wire 28 can be circular, and its diameter is 40-80um; the cross section of the back surface metal wire 28 The shape can also be square or triangular. The metal wire may be copper wire or silver-clad copper wire.

(5), as shown in Figure 5, a plurality of front surface metal wires 26 that are attached with aluminum-doped silver paste 24 are pasted on the front surface of the silicon chip in parallel at equal intervals according to the direction perpendicular to the front metal busbar electrode 20 and baked. Dry, the spacing between the front surface metal wires 26 is 1-3mm; then the back surface metal wires 28 attached with the silver paste 30 are pasted in parallel on the back of the silicon chip at equal intervals according to the direction perpendicular to the back metal main grid electrode 22. Surface and dry, the distance between the metal wires 26 on the front surface is 1-3mm;

(6) Place the above-mentioned N-type double-sided battery attached with metal wires in a sintering furnace for sintering. The sintering temperature is not higher than 900 degrees Celsius. The view is shown in Figure 7. So far, the metallization of the N-type double-sided battery is completed.

The metallization method of the N-type double-sided solar cell proposed by the present invention is compared with the metallization process of the conventional N-type double-sided solar cell. The difference of the present invention has the following two points: 1. The p+ doped region on the surface forms an ohmic contact with the n+ doped region, which greatly reduces the recombination rate between the metal electrode and silicon, thereby increasing the open circuit voltage of the N-type double-sided solar cell; 2. With the p+ doped region The metal thin grid lines in ohmic contact with the n+ doped region are respectively pasted on the front and rear surfaces of the silicon wafer in the direction perpendicular to the main grid electrode by metal wires coated with aluminum-doped silver paste and silver paste, and then dried and sintered. In this way, the silver paste consumption of the battery is greatly reduced while ensuring that the resistance of the metal fine grid wire does not increase, thereby reducing the production cost of the battery sheet.

This embodiment also provides an N-type double-sided solar cell, which includes an N-type crystalline silicon substrate 10, and the front surface of the N-type crystalline silicon substrate 10 includes p+ doped regions 12 from the inside to the outside and passivation antireflection on the front surface. Film 14; the back surface of the N-type crystalline silicon substrate includes an n+ doped region 16 and a back surface passivation film 18 sequentially from the inside to the outside, and the front surface of the N-type crystalline silicon substrate 10 includes a front metal main gate electrode 20 and a metal wire , the metal wire is connected to the p+ doped region 12 through silver-aluminum alloy; the back surface of the N-type crystalline silicon substrate 10 includes a back metal main gate electrode 22 and a metal wire, and the metal wire is connected to the n+ doped region 16 connected by silver.

The passivation anti-reflection film 14 in this embodiment is one or more of SiO2 dielectric film, SiNx dielectric film or Al2O3 dielectric film, and the passivation film 18 is a composite dielectric film composed of SiO2 dielectric film and SiNx dielectric film The thickness of the N-type crystalline silicon substrate 10 is 50-300 μm; the doping depth of the p+ doped region 12 is 0.5-2.0 μm; the thickness of the passivation anti-reflection film 14 is 70-110 nm; the thickness of the passivation film 18 is not less than 20 nm; the doping depth of the n+ doped region 16 is 0.5-2.0 μm. Preferably, the number of the front metal busbar electrodes 20 and the back metal busbar electrodes 22 is greater than 2, and the positions of the front metal busbar electrodes 20 and the rear metal busbar electrodes 22 correspond to each other and are evenly distributed in the N-type On the surface of the crystalline silicon substrate 10, the widths of the front metal main gate electrode 20 and the back metal main gate electrode 22 are all 0.5-3mm. The aluminum-doped silver paste or the silver paste adhered to the wire is discontinuously adhered to the wire or continuously adhered to the wire. The cross-sectional shape of the metal wire is circular, square or triangular, and the diameter of the circular metal wire is 40-80um.

This embodiment also provides an N-type double-sided solar cell assembly, including a front layer material connected from top to bottom, an encapsulation material, an N-type double-sided solar cell, an encapsulation material, a back layer material, and an N-type double-sided solar cell It is the above-mentioned N-type double-sided solar cell. The structure and working principle of the N-type double-sided solar cell assembly of this embodiment use technologies known in the art, and the improvement of the N-type double-sided solar cell assembly provided by the present invention only involves the above-mentioned N-type double-sided solar cell, and does not apply to other Some changes are made. Therefore, this description only details the N-type double-sided solar cell and its preparation method, and will not repeat the details of other components and working principles of the N-type double-sided solar cell module here. Those skilled in the art can realize the N-type bifacial solar cell module of the present invention on the basis of the content described in this specification.

This embodiment also provides an N-type double-sided solar cell system, including one or more than one N-type double-sided solar cell components connected in series, and the N-type double-sided solar cell component is the above-mentioned N-type double-sided solar cell components. The structure and working principle of the N-type double-sided solar cell system of this embodiment use technologies known in the art, and the improvement of the N-type double-sided solar cell system provided by the present invention only involves the above-mentioned N-type double-sided solar cells, and does not apply to other Some changes are made. Therefore, this description only details the N-type bifacial solar cell and its preparation method, and other components and working principles of the N-type bifacial solar cell system will not be repeated here. Those skilled in the art can realize the N-type bifacial solar cell system of the present invention on the basis of the content described in this specification.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention, although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand , the technical solution of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims (13)

1. A method for metallizing an N-type double-sided solar cell, characterized in that: comprising the following steps: (1), prepare a p+ doped region and an n+ doped region on the front surface and the back surface of the N-type crystalline silicon substrate, and prepare a passivation anti-reflection film on the front surface, and prepare a passivation film on the back surface; (2) Print metal paste on the front surface and the back surface of the N-type crystalline silicon substrate and dry to form the front metal busbar electrode and the back metal busbar electrode, the front metal busbar electrode and the p+ doped region No ohmic contact is formed, and the back metal main gate electrode does not form an ohmic contact with the n+ doped region; (3), paste the metal wire with aluminum-doped silver paste on the front surface of the N-type crystalline silicon substrate, paste the metal wire with the silver paste on the back surface of the N-type crystalline silicon substrate, after drying, After sintering, the metal wire forms ohmic contact with the p+ doped region and the n+ doped region respectively, and at the same time the metal wire and the main grid electrode also form ohmic contact, completing the metallization of the solar cell. 2. The metallization method of a kind of N-type double-sided solar cell according to claim 1, characterized in that: the passivation anti-reflection film is one or more of SiO2 dielectric film, SiNx dielectric film or Al2O3 dielectric film kind, the passivation film is a composite dielectric film composed of SiO2 dielectric film and SiNx dielectric film. 3. The metallization method of an N-type double-sided solar cell according to claim 1, characterized in that: the thickness of the N-type crystalline silicon substrate is 50-300 μm; the doping depth of the p+ doped region is 0.5 ~2.0 μm; the thickness of the passivation anti-reflection film is 70-110 nm; the thickness of the passivation film is not less than 20 nm; the doping depth of the n+ doped region is 0.5-2.0 μm. 4. The metallization method of a kind of N-type double-sided solar cell according to claim 1, characterized in that: the number of front metal main grid electrodes and back metal main grid electrodes is greater than 2, and the number of front metal main grid electrodes The setting position and the setting position of the back metal busbar electrode correspond to each other, and are evenly distributed on the surface of the N-type crystalline silicon substrate, and the width of the front metal busbar electrode and the back metal busbar electrode are both 0.5-3mm. 5. The metallization method of a kind of N-type double-sided solar cell according to claim 1, characterized in that: aluminum-doped silver paste or silver paste is adhered discontinuously on the metal wire or continuously attached to the metal wire superior. 6. The metallization method of an N-type double-sided solar cell according to any one of claims 1 to 5, characterized in that: the cross-sectional shape of the metal wire is circular, square or triangular, and the shape of the circular metal wire is The diameter is 40-80um. 7. the metallization method of a kind of N-type double-sided solar cell according to claim 1, is characterized in that: the method for pasting metal wire in step (3) is to be attached to a plurality of metal wires with aluminum-doped silver paste Paste it on the front surface of the N-type crystalline silicon substrate in parallel at equal intervals in the direction perpendicular to the front metal main grid electrode and dry it. The distance between the metal wires on the front surface is 1-3mm; then attach the metal wires with silver paste Paste on the back surface of the silicon wafer in parallel at equal intervals in the direction perpendicular to the back metal main grid electrode and dry, and the distance between the metal wires on the back surface is 1-3mm. 8 . The metallization method of an N-type double-sided solar cell according to claim 1 , wherein the sintering temperature in step (3) is not higher than 900 degrees Celsius. 9. An N-type double-sided solar cell, comprising an N-type crystalline silicon substrate, the front surface of the N-type crystalline silicon substrate includes a p+ doped region and a passivation anti-reflection film from the inside to the outside; the N-type crystalline silicon substrate The back surface includes an n+ doped region and a passivation film sequentially from the inside to the outside, and it is characterized in that: the front surface of the N-type crystalline silicon substrate includes a front metal busbar electrode and a front metal wire, and the front metal wire is connected to the p+ The doped region is connected by silver-aluminum alloy; the back surface of the N-type crystalline silicon substrate includes a back metal busbar electrode and a back metal wire, and the back metal wire is connected to the n+ doped region by silver. 10. A kind of N-type double-sided solar cell according to claim 9, characterized in that: the passivation anti-reflection film is one or more of SiO2 dielectric film, SiNx dielectric film or Al2O3 dielectric film, the The passivation film is a composite dielectric film composed of a SiO2 dielectric film and a SiNx dielectric film; the thickness of the N-type crystalline silicon substrate is 50-300 μm; the doping depth of the p+ doped region is 0.5-2.0 μm; the thickness of the passivation anti-reflection film is 70-110nm; the thickness of the passivation film is not less than 20nm; the doping depth of the n+ doped region is 0.5-2.0μm. 11. A kind of N-type double-sided solar cell according to claim 9, characterized in that: the number of the front metal main grid electrodes and the back metal main grid electrodes is greater than 2, the setting position of the front metal main grid electrodes and the back side The positions of the metal main gate electrodes correspond to each other and are evenly distributed on the surface of the N-type crystalline silicon substrate. The widths of the front metal main gate electrodes and the back metal main gate electrodes are both 0.5-3mm. 12. An N-type double-sided solar cell module, comprising a front layer material, an encapsulation material, an N-type double-sided solar cell, an encapsulation material, and a back layer material arranged sequentially from top to bottom, characterized in that: the N-type double-sided The planar solar cell is an N-type double-sided solar cell described in any one of claims 9-11. 13. An N-type double-sided solar cell system, comprising one or more than one N-type double-sided solar cell components connected in series, characterized in that: the N-type double-sided solar cell component is the one described in claim 12 N-type bifacial solar cell module.