CN216311815U

CN216311815U - TBC solar cell

Info

Publication number: CN216311815U
Application number: CN202121877876.6U
Authority: CN
Inventors: 宋志成; 李跃恒
Original assignee: Xidian University; Qinghai Huanghe Hydropower Development Co Ltd; Huanghe Hydropower Development Co Ltd; Xian Solar Power Branch of Qinghai Huanghe Hydropower Development Co Ltd; Xining Solar Power branch of Qinghai Huanghe Hydropower Development Co Ltd
Current assignee: Xidian University; Qinghai Huanghe Hydropower Development Co Ltd; Huanghe Hydropower Development Co Ltd; Xian Solar Power Branch of Qinghai Huanghe Hydropower Development Co Ltd; Xining Solar Power branch of Qinghai Huanghe Hydropower Development Co Ltd
Priority date: 2021-08-12
Filing date: 2021-08-12
Publication date: 2022-04-15
Anticipated expiration: 2031-08-12

Abstract

Disclosed is a TBC solar cell, comprising: a silicon wafer substrate having a front surface and a back surface; a silicon oxide layer deposited on the back surface of the silicon wafer substrate; a polysilicon layer deposited on the silicon oxide layer; the doped region comprises a P-type doped region and an N-type doped region, and the P-type doped region and the N-type doped region are sequentially and alternately arranged in a linear manner in the polycrystalline silicon layer; a first anti-reflection film deposited on the polysilicon layer; the second antireflection film is deposited on the front surface of the silicon wafer substrate; electrodes comprising a positive electrode and a negative electrode; the positive electrode forms ohmic contact with the P-type doped region through the first antireflection film, and the negative electrode forms ohmic contact with the N-type doped region through the first antireflection film. The TBC solar cell has the characteristics of simple preparation method, low preparation cost and high cell efficiency, is suitable for stable mass production, and is favorable for improving the mass production capacity and market competitiveness of the TBC solar cell.

Description

TBC solar cell

Technical Field

The utility model belongs to the technical field of solar cells, and particularly relates to a TBC (TBC) solar cell.

Background

Photovoltaic power generation is one of the main ways of utilizing solar energy at present, solar photovoltaic power generation has become a new industry which is generally concerned and intensively developed in all countries in the world due to the characteristics of cleanness, safety, convenience, high efficiency and the like, and the research and preparation of the TBC solar cell are beneficial to the utilization of solar energy resources, so that the method has very important significance for relieving resource crisis and improving ecological environment.

The preparation process of the TBC solar cell prepared in the prior art has the problems of long flow, almost twenty or more process steps, high manufacturing cost and the like, and the whole process has various unstable factors, for example, the preparation process comprises various chemical cleaning processes, so that the problems of passivation layer damage, short circuit of positive and negative electrodes, electric leakage and the like of the TBC solar cell are easily caused, and the efficiency improvement and the mass production stability of the TBC solar cell are seriously influenced.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems of the prior art, the present invention provides a TBC solar cell which is simple to manufacture, has high cell efficiency, and is suitable for stable mass production.

According to an aspect of an embodiment of the present invention, there is provided a TBC solar cell including: a silicon wafer substrate having a front surface and a back surface;

a silicon oxide layer deposited on the back surface of the silicon wafer substrate;

a polysilicon layer deposited on the silicon oxide layer;

the doped region comprises a P-type doped region and an N-type doped region, and the P-type doped region and the N-type doped region are sequentially and alternately arranged in a straight line in the polycrystalline silicon layer;

a first anti-reflective film deposited on the polysilicon layer;

the second antireflection film is deposited on the front surface of the silicon wafer substrate;

the electrode comprises a metal positive electrode and a metal negative electrode, the metal positive electrode penetrates through the first antireflection film to form ohmic contact with the P-type doped region, and the metal negative electrode penetrates through the first antireflection film to form ohmic contact with the N-type doped region.

In the TBC solar cell provided in the above aspect, the doping in the P-type doped region is boron doping; and the doping in the N-type doped region is phosphorus doping.

In the TBC solar cell provided in the above aspect, the width of the N-type doped region is 50um to 300um, and the width ratio of the N-type doped region to the P-type doped region is 2: 1-3: 1.

in the TBC solar cell provided in the above aspect, an isolation region is further provided between the adjacent N-type doped region and the P-type doped region, and the width of the isolation region is 5um to 100 um.

In the TBC solar cell provided in the above aspect, the sheet resistances of the N-type doped region and the P-type doped region are both 50 Ω · sq to 650 Ω · sq.

In the TBC solar cell provided in the above aspect, the silicon wafer substrate is an N-type silicon wafer substrate, and a textured structure is formed on a front surface of the silicon wafer substrate.

In the TBC solar cell provided in the above aspect, the thickness of the silicon oxide layer is 1nm to 20nm, and the thickness of the polycrystalline silicon layer is 5nm to 200 nm.

In the TBC solar cell provided in the above aspect, the first antireflection film and the second antireflection film are both silicon nitride antireflection films, and the thicknesses of the first antireflection film and the second antireflection film are both 60nm to 90 nm.

In the TBC solar cell provided in the above aspect, the electrode includes fine gate lines and main gate lines, the fine gate lines include first fine gate lines and second fine gate lines, and the main gate lines are perpendicular to the fine gate lines; the first thin gate line penetrates through the first antireflection film and forms ohmic contact with the P-type doped region and/or the N-type doped region, and the second thin gate line covers the first thin gate line.

In the TBC solar cell provided in the above aspect, the width of the second fine gate line is 20um to 100 um; the width of the main grid line is 0.05 mm-2 mm.

Has the advantages that: the TBC solar cell has the characteristics of simple preparation method, short preparation process and low preparation cost, avoids risks of damaging a passivation layer, short circuit of a positive electrode and a negative electrode, large electric leakage and the like caused by a chemical cleaning process as much as possible in the preparation process, and has high cell efficiency, so that the TBC solar cell can be suitable for stable mass production, and is beneficial to improving the mass production capacity and market competitiveness of the TBC solar cell.

Drawings

The above and other aspects, features and advantages of embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a structural diagram of a TBC solar cell according to an embodiment of the present invention.

In the attached drawing, a 10-N type silicon chip substrate, a 20-inverted pyramid suede, a 30-silicon oxide layer, a 40-polysilicon layer, a 50-doping layer, a 60-P type doping region, a 70-N type doping region, an 80-isolation region, a 90-first antireflection film, a 100-second antireflection film, a 110-positive electrode and a 120-negative electrode.

Detailed Description

In the present invention, the terms "disposed", "provided", "connected", and the like are to be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

The terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing and simplifying the description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the present invention can be understood by those skilled in the art as appropriate.

In order to solve the technical problems of the TBC solar cells prepared in the prior art as described in the background, a TBC solar cell is provided according to an embodiment of the present invention. The solar cell includes: a silicon wafer substrate having a front surface and a back surface; a silicon oxide layer deposited on the back surface of the silicon wafer substrate; a polysilicon layer deposited on the silicon oxide layer; the doped region comprises a P-type doped region and an N-type doped region, and the P-type doped region and the N-type doped region are sequentially and alternately arranged in a straight line in the polycrystalline silicon layer; a first anti-reflective film deposited on the polysilicon layer; the second antireflection film is deposited on the front surface of the silicon wafer substrate; the electrode comprises a metal positive electrode and a metal negative electrode, the metal positive electrode penetrates through the first antireflection film to form ohmic contact with the P-type doped region, and the metal negative electrode penetrates through the first antireflection film to form ohmic contact with the N-type doped region.

The TBC solar cell has the characteristics of simple preparation method, short preparation process, low preparation cost and high cell efficiency, is suitable for stable mass production, and is beneficial to improving the mass production capacity and market competitiveness of the TBC solar cell.

The TBC solar cell according to the present novel embodiment will be described in detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a TBC solar cell according to an embodiment of the present invention, and each part of the TBC solar cell provided by the present invention will be described in detail with reference to fig. 1.

In one example, the silicon wafer substrate is an N-type silicon wafer substrate 10 having a front surface and a back surface, and a textured structure 20 is formed on the front surface of the silicon wafer substrate 10.

In one example, the silicon oxide layer 30 is deposited on the back surface of the N-type silicon wafer substrate 10, wherein the thickness of the silicon oxide layer 30 is 1nm to 20 nm.

In one example, the polysilicon layer 40 is deposited on the silicon oxide layer 30, wherein the polysilicon layer has a thickness of 5nm to 200 nm.

In this embodiment, a polysilicon deposition apparatus is used to sequentially deposit and form the stacked silicon oxide layer 30 and the polysilicon layer 40 on the back surface of the N-type silicon wafer substrate 10 in a vacuum low-pressure environment, which is beneficial to improving the passivation of the cell and reducing the recombination of carriers.

In one example, the doped region is located in the polysilicon layer 40, wherein the doped layer includes a P-type doped region 50 and an N-type doped region 60, and the P-type doped region 50 and the N-type doped region 60 are sequentially and alternately arranged in a straight line in the polysilicon layer 40; and an isolation region 70 is further disposed between the adjacent N-type doped region 60 and the P-type doped region 50.

In one example, the sheet resistances of the P-type doped region 50 and the N-type doped region 60 are both 50 Ω · sq-650 Ω · sq; the width of the N-type doped region 60 is 50um to 300um, and the width ratio of the N-type doped region 60 to the P-type doped region 50 is 2: 1-3: 1; the width of the isolation region 70 is 5um to 100 um.

In one example, the doping in the P-type doped region 50 is boron doping and the doping in the N-type doped region 60 is phosphorus doping; the upper surfaces of the P-type doped region 50 and the N-type doped region 60 are slightly higher than or flush with the upper surface of the polysilicon layer 40, and during the process of forming the P-type doped region 50 and the N-type doped region 60, a portion of the doped source penetrates through the tunnel oxide layer (silicon oxide layer 30) and enters the surface of the N-type silicon substrate 10 at a high temperature.

An isolation region 70 is reserved between the N-type doped region 60 and the P-type doped region 50 to separately isolate the P-type doped region 50 and the N-type doped region 60; the separation and isolation of the P-type doped region 50 and the N-type doped region 60 by using printing means such as etching paste printing are avoided, and the problem that the printing paste line type of the TBC solar cell is easy to be unstable is further avoided.

In one example, the first antireflection film 80 is deposited on the polysilicon layer 40, and the second antireflection film 90 is deposited on the textured structure 20 on the front surface of the N-type silicon wafer substrate 10; the first antireflection film 80 and the second antireflection film 90 are both silicon nitride antireflection films, and the thicknesses of the first antireflection film 80 and the second antireflection film 90 are both 60nm to 90 nm.

By forming the silicon nitride antireflection film, the reflectivity of the surface of the substrate can be reduced, and the incident light utilization rate of the battery can be improved.

In one example, the electrodes include a metal positive electrode 100 and a metal negative electrode 110, the metal positive electrode 100 forms an ohmic contact with the P-type doped region 50 through the first anti-reflective film 80, and the metal negative electrode 110 forms an ohmic contact with the N-doped region 60 through the first anti-reflective film 80.

In one example, the electrode includes thin gate lines including a first thin gate line and a second thin gate line, and main gate lines including a positive electrode main gate line and a negative electrode main gate line, the main gate lines being perpendicular to the thin gate lines.

The first thin gate line penetrates through the first antireflection film 80 to form ohmic contact with the P-type doped region 50 and/or the N-type doped region 60, and the second thin gate line covers the first thin gate line.

In one example, the first fine grid line is formed by printing dots which are arranged in a straight line at equal intervals, wherein the diameters of the dots are 10um to 50um, and the distance between the centers of circles of adjacent dots is 20um to 200 um.

In another example, the first thin gate line may also be formed by printing line segments arranged in a straight line at equal intervals, wherein the line width of each line segment is 15um to 35um, the length of each line segment is 15um to 100um, and the distance between adjacent line segments is 30um to 300 um.

In this embodiment, the first fine grid line is formed by printing a first paste and then sintering at a first temperature, wherein the first temperature is not lower than 500 ℃ and can be determined according to the characteristics of the paste; the first paste is a fire-through paste, and the fire-through paste contains a high content of glass powder or lead, and can etch the first anti-reflection film 80, so that the first thin gate lines can penetrate through the first anti-reflection film 80 to form ohmic contacts with the N-type doped region 60 and/or the P-type doped region 50, wherein the first thin gate lines are all required to form ohmic contacts, otherwise, the filling factor FF (fill factor, which represents the ratio of the maximum output power Im · Vm to the limit output power Isc · Voc), of the battery, that is, FF ═ Vm)/(Isc · Voc)) is too low.

In one example, the line width of the second fine gate line is 20um to 100 um.

In this embodiment, the second fine grid line is formed by printing a second paste and then sintering at a second temperature, and the second paste covers the first paste; wherein the second temperature is not lower than 500 ℃, and can be determined according to the characteristics of the slurry; the second slurry is non-burn-through slurry, and the non-burn-through slurry contains low content of glass powder or lead, so that the first antireflection film 80 is not corroded.

In one example, the main gate line includes a positive electrode main gate line and a negative electrode main gate line, and the main gate line is perpendicular to the thin gate line; the width of the main grid line is 0.05 mm-2 mm, and the main grid line does not need to form ohmic contact.

In this embodiment, the main grid line is formed by printing a third paste and then drying the printed main grid line at a third temperature; the third slurry mainly comprises silver paste, resin and other organic components, the third temperature is not lower than 200 ℃, and the third temperature can be determined according to the characteristics of the slurry.

In this embodiment, an insulating paste is further printed between the thin gate lines and the main gate lines, that is, the insulating paste is printed above the second thin gate lines at intervals and below the main gate lines to realize the interval isolation of the thin gate lines and the main gate lines; wherein, the printing width of the insulating slurry is 0.1 mm-1 mm, and the length is 0.2 mm-5 mm.

In one example, the number of the thin grid lines is 100 to 1000, and the number of the positive electrode main grid lines (negative electrode main grid lines) is 3 to 100.

The manufacturing process of the TBC solar cell provided by the utility model is as follows:

step one, providing an N-type silicon wafer substrate 10, performing front side texturing on the N-type silicon wafer substrate 10 after double-side polishing, and forming a pyramid textured surface 20 on the front side of the N-type silicon wafer substrate 10.

Firstly, carrying out double-sided polishing on the N-type silicon wafer substrate 10 by using an SDE (software development environment) cleaning process so as to remove mechanical damage, metal ions and other impurities on the surface of the substrate; and then, carrying out front side texturing on the N-type silicon wafer substrate 10 subjected to double-side polishing by using groove type texturing equipment or dry-method texturing equipment so as to form an inverted pyramid textured structure 20 on the front side of the N-type silicon wafer substrate 10, thereby reducing the reflectivity of the surface of the substrate and improving the incident light utilization rate of the battery.

In a preferred example, the dry-felting apparatus is selected for face-side felting to improve the consistency of the felting and to facilitate lower reflectivity.

In the preparation process, only chemical cleaning equipment is needed to be used in the process of carrying out double-sided polishing and double-sided texturing on the N-type silicon wafer substrate 10, so that the subsequently deposited polycrystalline silicon layer 40 is prevented from being corroded by chemical liquid, and the increase of the leakage risk and instability of the battery due to poor controllability of chemical corrosion is avoided.

And step two, depositing the laminated silicon oxide layer 30 and the polysilicon layer 40 on the back surface of the N-type silicon wafer substrate 10 in sequence.

And thirdly, depositing a first silicon nitride mask on the polycrystalline silicon layer 40 by using silicon nitride deposition equipment, and slotting at a preset position of the first silicon nitride mask by using laser slotting equipment to form a first slotting region.

In one example, the first silicon nitride mask has a thickness of 30nm to 90 nm.

And fourthly, performing boron diffusion treatment on the first slotted region to form a P-type doped region 50.

Wherein, high-temperature diffusion furnace equipment or ion implantation equipment is used for boron diffusion treatment; preferably, ion implantation equipment is used for boron diffusion treatment, so that more uniform doping can be realized, the doping consistency is better, and the surface concentration and junction depth of doping are more stable and controllable.

And fifthly, depositing a second silicon nitride mask on the polycrystalline silicon layer 40 by using silicon nitride deposition equipment, wherein the thickness of the second silicon nitride mask is 30-90 nm.

Step six, slotting on the second silicon nitride mask by using laser slotting equipment to form a second slotting region, and carrying out phosphorus diffusion treatment on the second slotting region to form N-type doped regions 60 which are sequentially and alternately arranged in a straight line with the P-type doped regions 50; wherein, a high-temperature diffusion furnace device is used for carrying out phosphorus diffusion treatment.

An isolation region 70 is further disposed between the adjacent N-type doped region 60 and the P-type doped region 50; in the polysilicon layer 40, the isolation region 70 is formed directly from the undoped portion of the polysilicon layer 40, and on the surface of the polysilicon layer 40, the isolation region 70 is formed by retaining a portion of the silicon nitride mask when performing the trench opening by using the laser trench opening device.

And seventhly, etching the front side and the periphery of the N-type silicon wafer substrate 10 by using laser equipment or dry etching equipment to remove the diffusion layer on the front side and the periphery so as to avoid the risk of electric leakage.

In a preferred example, the front surface and the peripheral diffusion barrier layer of the N-type silicon wafer substrate 10 are removed by etching through a laser device, so that damage to the surface of the substrate can be reduced.

Step eight, depositing a layer of silicon nitride on both sides of the N-type silicon wafer substrate 10 to form a first anti-reflection film 80 and a second anti-reflection film 90 on the back and the front of the N-type silicon wafer substrate, respectively.

And step nine, respectively forming a metal negative electrode 110 in ohmic contact with the N-type doped region 60 and a metal positive electrode 100 in ohmic contact with the P-type doped region 50 on the back surface of the N-type silicon wafer substrate 10 through high-precision screen printing equipment to obtain the TBC solar cell. The method specifically comprises the following steps:

in summary, the TBC solar cell according to the embodiment of the present invention has the characteristics of simple preparation method, short preparation process, and low preparation cost, and the risks of damaging the passivation layer, short circuit between the positive electrode and the negative electrode, large electric leakage, and the like caused by the chemical cleaning process are avoided as much as possible in the preparation process, and the cell efficiency is high, so that the TBC solar cell can be suitable for stable mass production, and is beneficial to improving the mass production capability and market competitiveness of the TBC solar cell.

The foregoing description has described certain embodiments of this invention. Other embodiments are within the scope of the following claims.

Alternative embodiments of the present invention are described in detail with reference to the drawings, however, the embodiments of the present invention are not limited to the specific details in the above embodiments, and within the technical idea of the embodiments of the present invention, many simple modifications may be made to the technical solution of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the description is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A TBC solar cell, comprising:

a silicon wafer substrate having a front surface and a back surface;

a polysilicon layer deposited on the silicon oxide layer;

a first anti-reflective film deposited on the polysilicon layer;

2. The TBC solar cell of claim 1, wherein the doping in the P-type doped region is boron doping; and the doping in the N-type doped region is phosphorus doping.

3. The TBC solar cell of claim 2, wherein the width of the N-type doped region is 50um to 300um, and the width ratio of the N-type doped region to the P-type doped region is 2: 1-3: 1.

4. the TBC solar cell of claim 3, wherein an isolation region is further disposed between the adjacent N-type doped region and the adjacent P-type doped region, and the isolation region has a width of 5um to 100 um.

5. The TBC solar cell of any one of claims 1 to 4, wherein the sheet resistances of the N-type doped region and the P-type doped region are both 50 Ω -650 Ω -sq.

6. The TBC solar cell of claim 1, wherein the silicon wafer substrate is an N-type silicon wafer substrate, and a textured structure is formed on a front surface of the silicon wafer substrate.

7. The TBC solar cell of claim 1, wherein the silicon oxide layer has a thickness of 1nm to 20nm, and the polycrystalline silicon layer has a thickness of 5nm to 200 nm.

8. The TBC solar cell of claim 1, wherein the first and second anti-reflective films are both silicon nitride anti-reflective films, and wherein the first and second anti-reflective films are both 60nm to 90nm thick.

9. The TBC solar cell of claim 1, wherein the electrode comprises thin gate lines and main gate lines, the thin gate lines comprising a first thin gate line and a second thin gate line, the main gate lines being perpendicular to the thin gate lines; the first thin gate line penetrates through the first antireflection film and forms ohmic contact with the P-type doped region and/or the N-type doped region, and the second thin gate line covers the first thin gate line.

10. The TBC solar cell of claim 9, wherein the width of the second fine grid line is 20 to 100 um; the width of the main grid line is 0.05 mm-2 mm.