CN114714156A - Processing method of silicon wafer, control system, silicon wafer, solar cell and assembly of solar cell - Google Patents

Abstract

The application discloses a processing method of a silicon wafer, a control system, the silicon wafer, a solar cell and a component thereof, wherein the processing method of the silicon wafer comprises the following steps: processing a silicon wafer round bar to form a first cuboid silicon ingot with square two end faces and rectangular four side faces; integrally grinding one group of two opposite side surfaces to enable the end surfaces to be rectangular so as to form a second rectangular silicon ingot; and cutting the second cuboid silicon ingot along the direction vertical to the side surface to obtain the silicon wafer. The silicon wafer prepared by the method has the advantages of reducing processing difficulty, shortening processing time of the silicon wafer and reducing silicon material loss.

Description

Silicon wafer processing method, control system, silicon wafer, solar cell and components thereof

technical field

The present invention generally relates to the technical field of solar photovoltaic power generation, and in particular relates to a processing method of a silicon wafer, a control system, a silicon wafer, a solar cell and components thereof.

Background technique

With the decreasing stock of fossil energy and the aggravation of environmental pollution caused by its consumption, the utilization of clean and renewable energy has been paid more and more attention.

Solar energy is an inexhaustible clean and renewable energy that can be used by converting solar energy into electrical energy through solar cells.

Silicon wafers are an important component in the production of crystalline silicon solar cells. In the existing processing flow of silicon wafers, silicon wafer rods are cut by wire cutting or circular saw to form rectangular silicon ingots with square end faces. The four sides and four side edges of the cuboid silicon ingot are ground to obtain a square silicon wafer. If rectangular silicon wafers with different lengths and widths are required, it is generally necessary to adjust the size of the silicon wafer bar cutting process. This method requires the cutting process. It is very high, it takes a long time to adjust the processing size equipment, and the loss of silicon material is large.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a silicon wafer processing method, a control system, a silicon wafer, a solar cell and components thereof, so as to reduce the processing difficulty of the silicon wafer, shorten the processing time, and the silicon material loss.

In a first aspect, the present invention provides a method for processing a silicon wafer, comprising the following steps:

The silicon wafer rod is processed to form a first cuboid silicon ingot with square end faces and rectangular four sides;

Carrying out integral grinding on one set of the two opposite side faces, so that the end faces are ground into a rectangle, so as to form a second cuboid silicon ingot;

The second cuboid silicon ingot is cut in a direction perpendicular to the side surface to obtain the silicon wafer.

As an implementable manner, the aspect ratio of the rectangle is 1:(0.9-1).

As an achievable manner, the processing method of the silicon wafer further includes:

Grinding is performed on two opposite sides of the other group, and the grinding amounts of the two sides are different.

As an achievable manner, the grinding amount of the two sets of side surfaces differs by 1mm-10mm.

As an achievable manner, in the same group, the grinding amounts of the two opposite side surfaces are the same.

As an achievable manner, the four side edges of the first cuboid silicon ingot or the second cuboid silicon ingot are ground, and the side edges are edges parallel to the axis line of the silicon wafer rod.

In a second aspect, the present invention provides a control system for realizing the above processing method, comprising:

a first opposite side distance setting unit, used for setting a first target distance between two opposite first processing target sides;

The second opposite side distance setting unit is used to set a second target distance between two opposite second processing target sides;

The control unit is configured to control the grinding mechanism to grind two opposite sides of one group of the first cuboid silicon ingot according to the first target distance or the second target distance, so that the The end face is ground into a rectangle to form the second cuboid silicon ingot.

In a third aspect, the present invention provides a silicon wafer prepared by the above processing method, and the aspect ratio of the silicon wafer is 1:(0.9-1).

In a fourth aspect, the present invention provides a solar cell comprising the above-mentioned silicon wafer.

In a fifth aspect, the present invention provides a solar cell assembly, comprising a plurality of the above-mentioned solar cells, and a plurality of the solar cell arrays are arranged and fixed in a rectangular outer frame.

The above technical solution only needs to be controlled by the grinding process, such as grinding only one set of two opposite sides of the first cuboid silicon ingot, or adjusting the grinding amount of the two sets of opposite sides to form a rectangle. The silicon rod is cut to form a rectangular silicon wafer, and the silicon wafer prepared by the above method reduces the processing difficulty, shortens the processing time of the silicon wafer, and reduces the loss of silicon material.

Description of drawings

Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

1 is a flowchart of a method for processing a silicon wafer provided by an embodiment of the present invention;

2 is a perspective view of a first cuboid silicon ingot according to an embodiment of the present invention;

Fig. 3 is the front view of Fig. 2;

4 is a perspective view of a side edge of a first cuboid silicon ingot after grinding according to an embodiment of the invention;

Fig. 5 is the front view of Fig. 4;

FIG. 6 is a front view of a solar cell assembly provided by another embodiment of the present invention.

Detailed ways

The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the related invention, but not to limit the invention. In addition, it should be noted that, for the convenience of description, only the parts related to the invention are shown in the drawings.

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

As shown in FIG. 1 to FIG. 3 , the method for processing a silicon wafer provided by an embodiment of the present invention includes the following steps:

S1: Process the silicon wafer rod to form a first cuboid silicon ingot 5 with square end faces and rectangular four sides;

For example, but not limited to, through a crystal pulling process, the single crystal silicon in the molten state is subjected to operations such as seeding, necking, shouldering, and shouldering to form a silicon wafer rod. Before processing, the silicon wafer rod formed by crystal pulling can be divided into a plurality of shorter silicon wafer rods along the direction perpendicular to its core line for subsequent processing operations. Of course, it can also not be divided into For a plurality of short silicon wafer rods, only the head and tail parts at both ends can be cut off; in other implementations, the two ends can also be cut off after side processing.

The silicon wafer rod can be cut in the direction parallel to the core line of the silicon wafer rod by wire cutting processing equipment, and then the head and tail parts at both ends are cut off to form a square end face and a rectangle on the four sides. The first cuboid silicon ingot 5. Among them, the four sides are the No. 1 side, the No. 2 side, the No. 3 side, and the No. 4 side, the No. 1 side and the No. 3 side are a group of two opposite sides A1, A2, the No. 2 side and the No. 4 side are another A set of opposite sides B1, B2.

S2: Perform overall grinding on one set of opposite sides A1, A2 (or B1, B2). The overall grinding here refers to grinding the entire surface of the corresponding side, that is, the ground The shape and area of the side surface remain unchanged, while the width and area of the unground side surface are reduced, so that the end surface is ground into a rectangle to form a second cuboid silicon ingot;

The side surfaces of the first rectangular parallelepiped silicon ingot 5 are ground by grinding equipment, which may be only one set of opposite two side surfaces A1 and A2 (or B1 and B2 ).

When grinding any set of opposite sides A1, A2 (or B1, B2), the two sides A1, A2 (or B1, B2) can be ground at the same time, or one side A1 (or one side A1) Or B1) and then grind the other side A2 (or B2).

In this example, it is taken as an example to grind a group of opposite two side surfaces A1, A2 (or B1, B2) at the same time, so as to improve the work efficiency. During the processing, the first cuboid silicon ingot 5 obtained by processing is placed on the workbench of the grinding equipment. The grinding equipment has two sets of grinding tools, which are located on both sides of the first cuboid silicon ingot 5 respectively, and adjust the first The position of the cuboid silicon ingot 5 on the workbench is such that the central axis of the first cuboid silicon ingot 5 in the longitudinal direction is located in the symmetry plane of the two sets of grinding tools. For example, the grinding tools can be grinding wheels with vertical axes, grinding tools and workbench Relative translation can occur. For example, the worktable can reciprocate in the horizontal direction, while the abrasive tool can not move in the horizontal direction. In some cases, the abrasive tool can move up and down in the vertical direction to make the grinding tool The cutting position covers the entire side. Of course, in other cases, the table can also move up and down in addition to the horizontal reciprocating motion. Through the preset target distance between the two sides, the reciprocating motion of the worktable is controlled, and the two rotating grinding wheels are moved relative to each other, so that a set of opposite sides A1, A2 (or B1) of the first cuboid silicon ingot 5 are simultaneously , B2) for grinding.

Of course, in other examples, the first target distance between the two opposite first machining target side surfaces and the distance between the two opposite second machining target side surfaces can also be preset in the control system of the grinding device. the second target distance. First, grind one set of side surfaces of the first cuboid silicon ingot 5 at the first target distance or the second target distance, then rotate the first cuboid silicon ingot 5 along the central axis of the length direction by 90°, and then use Another set of sides is ground at another target distance to form a second cuboid silicon ingot.

S3: Cut the second rectangular parallelepiped silicon ingot along a direction perpendicular to the side surfaces A1, A2, B1, and B2 to obtain the silicon wafer.

For example, but not limited to, use a multi-wire cutting slicer to cut the second cuboid silicon ingot in a direction perpendicular to the side surface of the second cuboid silicon ingot to obtain a silicon wafer with a predetermined thickness.

The above solution only needs to be controlled by the grinding process, such as grinding only one set of two opposite sides of the first cuboid silicon ingot, or adjusting the grinding amount of the two sets of opposite sides to form a rectangular silicon ingot. The silicon wafer is cut to form a rectangular silicon wafer, and the silicon wafer prepared by the above method reduces the processing difficulty, shortens the processing time of the silicon wafer, and reduces the loss of silicon material.

As an achievable manner, the aspect ratio of the rectangle is 1:(0.9-1), that is, the aspect ratio of the silicon wafer is 1:(0.9-1); for example, 1:0.91; 1:0.92; 1:0.95 ; 1:0.98 etc. Among them, (0.9-1) is an open interval from 0.9 to 1.

As an achievable manner, the processing method of the silicon wafer further includes:

Grinding is performed on two opposite sides of the other group, and the grinding amounts of the two sides are different. That is, the two sets of opposing side surfaces A1 , A2 , B1 , and B2 of the first rectangular parallelepiped silicon ingot 5 are both ground, and the grinding amounts of the two sets of opposing side surfaces A1 , A2 , B1 , and B2 are different. For example, but not limited to, grinding the two opposite sides A1 and A2 of one group first, then rotating the first rectangular parallelepiped silicon ingot 5 by 90° along the axis of the silicon wafer rod, and then grinding the other group. The two opposite sides B1 and B2 are ground, and the grinding amount of one set of opposite sides A1 and A2 is 1mm, and the grinding amount of the other set of opposite sides B1 and B2 is 3mm, etc. This is only for illustration. The different grinding amounts of the two groups of opposite sides are not the only limitation of their respective grinding amounts.

After grinding one set of opposite sides A1, A2 (or B1, B2) of the first cuboid silicon ingot 5, rotate the first cuboid silicon ingot 5 by 90°, and then grind the other set of opposite sides. B1, B2 (or A1, A2).

As an achievable manner, in order to ensure the processing efficiency and reduce the loss of silicon material during the processing, the grinding amount of the two groups relative to the side surfaces A1, A2, B1, and B2 differs by 1mm-10mm.

As an achievable manner, the two sets of grinding tools of the grinding equipment are controlled to move synchronously, so that in the same group, the grinding amounts of the two opposite sides A1, A2 (or B1, B2) are the same.

As an achievable manner, referring to FIG. 4 and FIG. 5 , in order to prevent stress concentration and avoid subsequent problems such as cracking and fragmentation of silicon wafers, the first cuboid silicon ingot 5 or the second cuboid silicon ingot 5 or the second cuboid The four side edges 1 of the silicon ingot are ground to achieve the purpose of chamfering 2, so as to overcome the problem that the corresponding edge of the silicon ingot is too sharp and has stress concentration. The side edge 1 is an edge parallel to the core line of the silicon wafer rod.

The side edge 1 can be ground before each side A1, A2, B1, B2 is ground, or after each side A1, A2, B1, B2 is ground, and it can also be interspersed in two sets of opposite sides A1, A2 , B1, B2 grinding between.

As an achievable manner, the grinding includes a first grinding process and a second grinding process performed in sequence, and the machining roughness of the second grinding process is smaller than that of the first grinding process. Through two grinding processes, first rough grinding, and then fine grinding, generally fine grinding to a mirror effect.

In a second aspect, the present invention provides a control system for realizing the above processing method, comprising:

a first opposite side distance setting unit, used for setting a first target distance between two opposite first processing target sides;

The second opposite side distance setting unit is used to set a second target distance between two opposite second processing target sides;

Wherein, the first target distance and the second target distance respectively represent the distances between the corresponding opposite sides of the silicon ingot before the silicon wafer is cut after grinding. For example, if only one set of opposite sides of the first cuboid silicon ingot 5 is ground, and the other set of sides is not ground, the distance between the ground set of opposite sides can be the first target distance, The second target distance can also be used; if both groups of opposite sides of the first cuboid silicon ingot 5 are ground, the distance between one group of the ground opposite sides can be the first target distance, and the other group A second target distance may be used for the distance between the opposite sides.

The control unit is configured to control the grinding mechanism to grind two opposite sides of one group of the first cuboid silicon ingot according to the first target distance or the second target distance, so that the The end face is ground into a rectangle to form the second cuboid silicon ingot.

Since the control system has a first opposite side distance setting unit and a second opposite side distance setting unit, the first target distance and the second target distance can be separately set respectively, and the first target distance and the second target distance can be set as two One of the set of opposite sides of the first cuboid silicon ingot 5 is ground, while the other set of sides is not ground; alternatively, one set of the opposite sides of the first cuboid silicon ingot 5 is ground with the first target distance Grinding, using the second target distance to grind another group of opposite sides of the first cuboid silicon ingot 5; to obtain a second cuboid silicon ingot, and cutting the second cuboid silicon ingot to obtain the desired silicon wafer.

In a third aspect, the present invention provides a silicon wafer prepared by the above processing method, and the aspect ratio of the silicon wafer is 1:(0.9-1).

The silicon wafer is generally rectangular, or a shape after chamfering/rounding the four corners of the rectangle (it may be called a chamfered rectangle or a rounded rectangle).

The silicon wafer may be a monocrystalline silicon wafer or a polycrystalline silicon wafer.

In a fourth aspect, the present invention provides a solar cell comprising the above-mentioned silicon wafer.

In a fifth aspect, as shown in FIG. 6 , the present invention provides a solar cell module, comprising a plurality of the above-mentioned solar cells 4 , and the plurality of the solar cells 4 are arranged and fixed in the rectangular outer frame 3 in an array.

In this example, the array is arranged with 5 rows and 10 columns of solar cells 4 .

In the above scheme, the solar cell 4 made of rectangular silicon wafers can make full use of the inner space of the rectangular outer frame of the solar cell module to reduce or even eliminate the use of square silicon wafers to make solar cell modules in the prior art. When the solar cell 4 and the rectangular outer frame of the solar cell module are left blank, the proportion of the total area of the solar cell 4 in the solar cell module is increased, so as to improve the photoelectric conversion rate of the module.

It should be understood that the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", "vertical" "," "horizontal", "top", "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description , rather than indicating or implying that the indicated device or element must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, and should also cover, without departing from the inventive concept, the above-mentioned technical features or their Other technical solutions formed by any combination of equivalent features. For example, a technical solution is formed by replacing the above-mentioned features with the technical features disclosed in this application (but not limited to) with similar functions.

Claims (10)

1. a processing method of silicon wafer, is characterized in that, comprises the following steps: The silicon wafer rod is processed to form a first cuboid silicon ingot with square end faces and rectangular four sides; Carrying out integral grinding on one set of the two opposite side faces, so that the end faces are ground into a rectangle, so as to form a second cuboid silicon ingot; The second cuboid silicon ingot is cut in a direction perpendicular to the side surface to obtain the silicon wafer. 2 . The method for processing a silicon wafer according to claim 1 , wherein the aspect ratio of the rectangle is 1:(0.9-1). 3 . 3. The processing method of silicon wafer according to claim 1 or 2, characterized in that, further comprising: Grinding is performed on two opposite sides of the other group, and the grinding amounts of the two sides are different. 4 . The method for processing a silicon wafer according to claim 3 , wherein the grinding amount of the two groups of the side surfaces differs by 1 mm-10 mm. 5 . 5 . The method for processing a silicon wafer according to claim 4 , wherein, in the same group, the grinding amounts of the two opposite side surfaces are the same. 6 . 6. The method for processing a silicon wafer according to claim 1 or 2, wherein the four side edges of the first cuboid silicon ingot or the second cuboid silicon ingot are ground, and the side edges are The edge parallel to the axis of the silicon wafer rod. 7. A control system for realizing the processing method according to any one of claims 1-6, characterized in that, comprising: a first opposite side distance setting unit, used for setting a first target distance between two opposite first processing target sides; The second opposite side distance setting unit is used to set a second target distance between two opposite second processing target sides; The control unit is configured to control the grinding mechanism to grind two opposite sides of one group of the first cuboid silicon ingot according to the first target distance or the second target distance, so that the The end face is ground into a rectangle to form the second cuboid silicon ingot. 8 . A silicon wafer, characterized in that it is prepared by the processing method according to any one of claims 1 to 6 , and the aspect ratio of the silicon wafer is 1:(0.9-1). 9 . A solar cell, comprising the silicon wafer of claim 8 . 10 . 10. A solar cell assembly, comprising a plurality of solar cells as claimed in claim 9, wherein a plurality of the solar cell arrays are arranged and fixed in a rectangular outer frame.

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