CN211062729U

CN211062729U - Laser-doped PERC (Positive electrode collector) battery

Info

Publication number: CN211062729U
Application number: CN202020277515.7U
Authority: CN
Inventors: 张薛丹; 费存勇; 赵福祥; 袁晓佳
Original assignee: Hanwha SolarOne Qidong Co Ltd
Current assignee: Hanwha Q Cells Qidong Co Ltd
Priority date: 2020-03-09
Filing date: 2020-03-09
Publication date: 2020-07-21
Anticipated expiration: 2030-03-09

Abstract

The utility model discloses a laser doping PERC battery, which comprises a crystalline silicon substrate, wherein the battery structure comprises a plurality of main grid heavily doped regions arranged on the crystalline silicon substrate, main grid lines arranged on the main grid heavily doped regions, a plurality of fine grid heavily doped regions vertically arranged with the main grid heavily doped regions and fine grid lines arranged on the fine grid heavily doped regions; the main gate heavily doped region and the fine gate heavily doped region are formed by laser doping, the outer contour shape of the main gate heavily doped region corresponds to the outer contour shape of the main gate lines, the number of the main gate heavily doped regions is less than or equal to the number of the main gate lines, the main gate heavily doped region is in a point-like or long-strip-shaped structure, and the sheet resistance range of the main gate heavily doped region is 30-120 omega. The PERC battery provided by the utility model is beneficial to the combination of the main grid silver paste and the silicon substrate, reduces the ohmic contact of the silver-silicon alloy and improves the filling factor; meanwhile, the metal recombination probability under the main grid is reduced, and the open-circuit voltage Voc is improved, so that the battery efficiency is improved.

Description

Laser-doped PERC (Positive electrode collector) battery

Technical Field

The utility model relates to a crystalline silicon solar cell manufacturing system field especially relates to a laser doping PERC battery.

Background

Solar photovoltaic power generation has become a new industry which is generally concerned and intensively developed all over the world due to the characteristics of cleanness, safety, convenience, high efficiency and the like. In the current solar cell technology field, the application of high efficiency cell technology is continuously improved, for example, the conversion efficiency of a PERC high efficiency cell is continuously improved, and in the continuous superposition technology, one of the high efficiency cells can be doped by laser to prepare a selective emitter electrode (SE) cell. Under an ideal state, the square resistance of an area without printing the metal paste (namely without the silver-silicon alloy) is high, the open-circuit voltage and the short-circuit current of the solar cell are improved, the square resistance of the area with printing the metal paste is low (the depth of a PN junction is increased, the phosphorus atom concentration on the surface is increased), the contact resistance of the silver-silicon alloy is reduced, the filling factor of the solar cell is inhibited from being further reduced, and therefore the efficiency of the solar cell can be effectively improved, and the PN junction depth and the phosphorus atom concentration on the surface of the silicon wafer are improved.

According to the principle of a process with different requirements, namely a selective emitter technology and a laser doping selective emitter electrode (SE) cell, after high sheet resistance diffusion is carried out on a crystalline silicon wafer, a phosphorus source in PSG is pushed into the silicon wafer by laser doping to form a high-concentration heavily doped region, so that ohmic contact is facilitated, and FF is improved; the shallow doped region without laser doping has a lower relative concentration, gradient doping is formed in the silicon wafer, the width of a P-N junction region is widened, and the open-circuit voltage is improved; meanwhile, the shallow junction can better absorb sunlight, the spectrum of the short wave band in the sunlight corresponding to the shallow junction contains more photons in the spectrum in the range, and better blue wave response can be obtained, so that the short-circuit current Isc is improved.

The conventional selective emitter electrode (SE) cell prepared by laser doping ignores the problems that the ohmic contact resistance is large and the fill factor FF value is lost due to high square resistance when the metal of the main gate region is in contact with the crystalline silicon, so that the cell efficiency has certain loss.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem that exists among the prior art, the utility model provides a laser doping PERC battery to solve in conventional laser doping SE battery, because the contact resistance that the regional silver-silicon alloy department of main grid that high sheet resistance arouses changes big problem, technical scheme is as follows:

the utility model provides a laser doping PERC battery, including the crystalline silicon base member, the battery structure is including setting up a plurality of main grid heavy doping regions on the crystalline silicon base member, setting up the main grid line on main grid heavy doping region, with a plurality of thin grid heavy doping regions that main grid heavy doping region set up perpendicularly and set up the thin grid line on thin grid heavy doping region, main grid heavy doping region and main grid line parallel arrangement, thin grid heavy doping region and thin grid line parallel arrangement, keep the interval of predetermineeing between every two adjacent main grid heavy doping regions, keep the interval of predetermineeing between every two adjacent thin grid heavy doping regions; the number of the main gate heavily doped regions is less than or equal to that of the main gate lines, and the number of the fine gate heavily doped regions is less than or equal to that of the fine gate lines;

the main gate heavily doped region and the fine gate heavily doped region are formed by laser doping, the outer contour shape of the main gate heavily doped region corresponds to that of the main gate line, the main gate heavily doped region is of a dot or strip structure, the sheet resistance range of the main gate heavily doped region is 30-120 omega, and the width range of the main gate heavily doped region is set to be 30-150 um.

Furthermore, the main gate heavily doped region is of a continuous strip-shaped structure; or the main gate heavily doped region is of a discontinuous structure, and the length range of the gap is set to be 10-50 mm.

Further, the main gate heavily doped region is of a dot structure, and the diameter range of each dot is set to be 30-150 um.

Further, the width of the main gate heavily doped region is equal to the width of the fine gate heavily doped region.

Further, the length range of the heavily doped main gate region is set to be 100-210 mm.

Further, the main gate heavily doped region is arranged on the fine gate heavily doped region.

Further, the main gate heavily doped region is arranged below the fine gate heavily doped region.

Furthermore, the plurality of main gate heavily doped regions are distributed at equal intervals, and the plurality of fine gate heavily doped regions are distributed at equal intervals.

Further, the length of the main gate heavily doped region is greater than or equal to the length of the main gate line.

Furthermore, a fine gate heavily doped region, a lightly doped region, an upper silicon nitride layer and a front surface metal layer are sequentially arranged on the upper surface of the crystalline silicon substrate from bottom to top, an aluminum oxide layer, a lower silicon nitride layer and a back surface metal layer are sequentially arranged on the lower surface of the crystalline silicon substrate from top to bottom, and the lightly doped region is formed by diffusion; the aluminum oxide layer and the lower silicon nitride layer are both provided with laser grooves, and the back surface metal layer and the crystal silicon substrate are in line contact through the laser grooves.

The utility model provides a beneficial effect that technical scheme brought as follows:

a. the laser-doped PERC battery provided by the utility model is beneficial to the combination of the main grid silver paste and the silicon substrate by increasing the heavily doped structure of the main grid region, reduces the ohmic contact of the silver-silicon alloy and improves the fill factor FF; meanwhile, the concentration of heavily doped phosphorus atoms in the main gate region is increased, so that the concentration of electrons under the main gate is increased, the metal recombination probability under the main gate is reduced, the increase of the open-circuit voltage Voc is facilitated, and the battery efficiency is improved;

b. compared with a conventional battery manufacturing mode, the laser doping PERC battery provided by the application only needs to change a laser process in the manufacturing process, extra processes and cost do not need to be added, and the efficiency of a battery piece can be improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a cross-sectional view of a laser-doped PERC cell provided by an embodiment of the present invention;

fig. 2 is a top view of a main gate heavily doped region and a fine gate heavily doped region of a laser-doped PERC cell provided in an embodiment of the present invention.

Wherein the reference numerals include: 1-crystal silicon substrate, 2-main gate heavily doped region, 3-fine gate heavily doped region, 4-lightly doped region, 5-upper silicon nitride layer, 6-front surface metal layer, 7-lower silicon nitride layer, 8-back surface metal layer, and 9-laser grooving.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.

In one embodiment of the present invention, a laser doped PERC cell is provided, with specific structure referring to figures 1 and 2, the solar cell comprises a crystalline silicon substrate 1, wherein the cell structure comprises a plurality of main grid heavily doped regions 2 arranged on the crystalline silicon substrate 1, main grid lines arranged on the main grid heavily doped regions 2, a plurality of fine grid heavily doped regions 3 arranged perpendicular to the main grid heavily doped regions 2 and fine grid lines arranged on the fine grid heavily doped regions 3, the number of the heavily doped main gate regions 2 is the same as or less than the number of the main gate lines, and is usually 3-12, when the number of the main gate heavily doped regions 2 is the same as that of the main gate lines, the heavily doped regions are increased, the electron concentration under all the main gate areas is improved, the contact is better, but the opening pressure is slightly damaged, and the laser slightly damages the surface of the crystalline silicon substrate; when the number of the main gate heavily doped regions 2 is smaller than that of the main gate lines, the contact is poor, the influence on the on-voltage is small, and the damage of laser to the surface of the crystal silicon substrate is small, so that the number of the main gate heavily doped regions 2 can be selected according to actual needs. The number of the fine gate heavily doped regions 3 is less than or equal to that of the fine gate lines.

The main gate heavily doped region 2 is arranged in parallel with the main gate line, that is, the main gate heavily doped region 2 is arranged along the length direction of the main gate line (as shown in the X-axis direction in fig. 2); the thin gate heavily doped region 3 is arranged in parallel with the thin gate line, that is, the thin gate heavily doped region 3 is arranged along the length direction of the thin gate line (e.g., the Y-axis direction in fig. 2), the main gate line is arranged perpendicular to the thin gate line, and the main gate heavily doped region 2 is arranged perpendicular to the thin gate heavily doped region 3, as shown in fig. 2. A preset interval is kept between every two adjacent main gate heavily doped regions 2, a preset interval is kept between every two adjacent fine gate heavily doped regions 3, and the main gate heavily doped regions 2 are distributed at equal intervals or unequal intervals, preferably at equal intervals; the fine gate heavily doped regions 3 are distributed at equal intervals or unequal intervals, preferably at equal intervals.

The main grid heavily doped region 2 and the fine grid heavily doped region 3 are both formed by laser doping, namely, in a conventional laser doping process, a laser doped region consistent with the distribution of the main grids in the screen printing plate graph in a printing process is added, and a phosphorus source in phosphorosilicate glass on a silicon wafer is further pushed into the silicon wafer by laser, so that the heavy doping below the main grid region is realized to form a main grid heavily doped region 2 structure.

The main gate heavily doped region 2 has the following specific structure: the outline shape of the main gate heavily doped region 2 corresponds to the outline shape of the main gate line, that is, the structure of the main gate heavily doped region 2 is mainly adjusted according to the shape of the main gate line, usually, the main gate line is a long strip structure, the main gate heavily doped region 2 is a long strip structure or a dot structure, the main gate heavily doped region 2 is a continuous (uninterrupted) long strip structure, and the length range of the main gate heavily doped region 2 is set to 100-210 mm; the length of the main grid heavily doped region 2 is greater than or equal to that of the main grid line; the square resistance range of the main gate heavily doped region 2 is 30-120 omega; the main gate heavily doped region 2 is of a discontinuous structure, and the length range of the gap is set to be 10-50 mm. The main gate heavily doped region 2 is a dot structure, and the diameter range of each dot is set to be 30-150 um. Meanwhile, the main gate heavily doped region 2 is a region which is preferably consistent with the distribution of the thin gate lines in the screen printing plate graph in the printing process, the width of the main gate heavily doped region 2 is equal to or not equal to the width of the thin gate heavily doped region 3, preferably equal to the width of one laser spot, and the width ranges of the main gate heavily doped region 2 and the thin gate heavily doped region are both set to be 30-150 um; if not, the laser emitter can be adjusted.

In the laser doping process, a laser doping region (main gate heavily doped region) consistent with the distribution of the fine gates in the screen pattern in the printing process can be added, and then a laser doping region (fine gate heavily doped region) consistent with the distribution of the main gates in the screen pattern in the printing process is added, so that the main gate heavily doped region 2 can be formed and arranged on the fine gate heavily doped region 3, or a laser doping region (main gate heavily doped region) consistent with the distribution of the main gates in the screen pattern in the printing process can be added, and then a laser doping region (fine gate heavily doped region) consistent with the distribution of the fine gates in the screen pattern in the printing process is added, so that the main gate heavily doped region 2 is arranged below the fine gate heavily doped region 3.

In the embodiment provided by the utility model, the upper surface of the crystal silicon substrate 1 is provided with a fine gate heavily doped region 3 (namely n + + layer), a lightly doped region 4 (namely n + layer formed by diffusion), an upper silicon nitride layer 5 and a front surface metal layer 6 from bottom to top in sequence, and a main gate heavily doped region 2 (namely n + + layer) is arranged on the fine gate heavily doped region 3; an aluminum oxide layer, a lower silicon nitride layer 7 and a back surface metal layer 8 are sequentially arranged on the lower surface of the crystal silicon substrate 1 from top to bottom, and the lightly doped region 4 is formed by diffusion; the aluminum oxide layer and the lower silicon nitride layer 7 are both provided with laser grooves 9, and the back surface metal layer 8 and the crystalline silicon substrate 1 are in line contact through the laser grooves 9, as shown in fig. 2.

To conventional laser doping SE battery (be referred to conventional battery for short) and the utility model discloses in increase in the laser technology to the heavily doped laser doping SE battery (be referred to this application for short) of main grid part form the test, specific experimental contrast data see the following table.

Table 1 comparison of the performance of the batteries provided herein with conventional batteries

	Eff(％)	Uoc(V)	Isc(A)	FF(％)
					Conventional battery	22.36％	0.6815	9.813	81.67
This application	22.41％	0.6822	9.82	81.73

Can know by the last table, compare in conventional laser doping SE battery, the utility model discloses in increase the laser process in to the heavily doped laser doping SE battery of main grid part, can promote open circuit voltage Voc (increase 0.0006V), short-circuit current Isc (increase 0.0007A), fill factor FF (increase 0.06%), and then promote battery efficiency Eff (improve and increase 0.05%).

Compare in conventional PERC battery structure, the utility model provides a battery structure's advantage lies in: the heavy doping of the main gate region (the structure of the main gate heavy doping region 2) is increased, the combination of main gate silver paste and a silicon substrate is facilitated, the ohmic contact of silver-silicon alloy is reduced, and the filling factor FF is improved; meanwhile, the concentration of heavily doped phosphorus atoms in the main gate region is increased, so that the concentration of electrons under the main gate is increased, the metal recombination probability under the main gate is reduced, and the increase of the open-circuit voltage Voc is facilitated; thereby resulting in a gain in cell efficiency; in addition, compared with a conventional battery manufacturing mode, the laser doping PERC battery provided by the application only needs to change a laser process in the manufacturing process, and extra processes and cost do not need to be added, so that the efficiency of a battery piece can be improved.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser-doped PERC battery comprises a crystal silicon substrate (1), and is characterized in that the battery structure comprises a plurality of main gate heavily-doped regions (2) arranged on the crystal silicon substrate (1), main gate lines arranged on the main gate heavily-doped regions (2), a plurality of fine gate heavily-doped regions (3) arranged perpendicular to the main gate heavily-doped regions (2), and fine gate lines arranged on the fine gate heavily-doped regions (3), wherein the main gate heavily-doped regions (2) are arranged in parallel with the main gate lines, the fine gate heavily-doped regions (3) are arranged in parallel with the fine gate lines, a preset interval is kept between every two adjacent main gate heavily-doped regions (2), and a preset interval is kept between every two adjacent fine gate heavily-doped regions (3); the number of the main gate heavily doped regions (2) is less than or equal to that of the main gate lines, and the number of the fine gate heavily doped regions (3) is less than or equal to that of the fine gate lines;

the main gate heavy doping region (2) and the fine gate heavy doping region (3) are formed through laser doping, the outer contour shape of the main gate heavy doping region (2) corresponds to the outer contour shape of a main gate line, the main gate heavy doping region (2) is of a point-shaped or long-strip-shaped structure, the sheet resistance range of the main gate heavy doping region (2) is 30-120 omega, and the width range of the main gate heavy doping region (2) is set to be 30-150 um.

2. The laser-doped PERC cell according to claim 1, wherein the heavily doped main gate region (2) is a continuous elongated structure; or the main gate heavily doped region (2) is of a discontinuous structure, and the length range of the gap is set to be 10-50 mm.

3. The laser-doped PERC cell according to claim 1, wherein the heavily doped main gate region (2) is a dot-like structure, and the diameter of each dot is set to be in the range of 30-150 um.

4. The laser-doped PERC cell according to claim 1, wherein the width of the main gate heavily doped region (2) is equal to the width of the fine gate heavily doped region (3).

5. The laser-doped PERC cell as claimed in claim 1, wherein the length of the heavily doped main gate region (2) is set to 100-210 mm.

6. The laser-doped PERC cell according to claim 1, wherein the heavily doped main gate region (2) is arranged on the heavily doped fine gate region (3).

7. The laser-doped PERC cell according to claim 1, wherein the heavily doped main gate region (2) is arranged below the heavily doped fine gate region (3).

8. The laser-doped PERC cell according to claim 1, wherein the plurality of heavily doped main gate regions (2) are equally spaced and the plurality of heavily doped fine gate regions (3) are equally spaced.

9. The laser-doped PERC cell of claim 1, wherein the length of the heavily doped main gate region (2) is greater than or equal to the length of the main gate line.

10. The laser-doped PERC battery as claimed in claim 1, wherein the upper surface of the crystalline silicon substrate (1) is sequentially provided with a fine gate heavily doped region (3), a lightly doped region (4), an upper silicon nitride layer (5) and a front surface metal layer (6) from bottom to top, the lower surface of the crystalline silicon substrate (1) is sequentially provided with an aluminum oxide layer, a lower silicon nitride layer (7) and a back surface metal layer (8) from top to bottom, and the lightly doped region (4) is formed by diffusion;

the aluminum oxide layer and the lower silicon nitride layer (7) are both provided with laser grooves (9), and the back surface metal layer (8) and the crystalline silicon substrate (1) are in line contact through the laser grooves (9).