KR101290106B1 - Method for manufacturing solar cell using laser - Google Patents

Abstract

PURPOSE: A method for processing a solar cell by a laser is provided to improve the yield of an electrode on a solar panel by minimizing standby time included in a vector to move the laser. CONSTITUTION: A first mark vector (31) is formed along a line to form a bus bar line. The bus bar line is formed along the first mark vector. A second mark vector (32) is formed along a line to form a finger line which is overlapped with the bus bar line. A second modulation signal is overlapped. The finger line is formed along the second mark vector.

Description

Solar cell processing method using a laser {Method for manufacturing solar cell using laser}

The present invention relates to a solar cell processing method using a laser, and more particularly, to a solar cell processing method using a laser to form an electrode pattern on the surface of the solar cell substrate by irradiating a laser beam on the solar cell substrate.

Solar cells are semiconductor devices that convert light energy directly into electrical energy using the Photo Voltanic Effect. The photovoltaic effect is a phenomenon in which strong light is incident on a P-N junction of a semiconductor or a metal having a rectifying action and a semiconductor interface, and electrons and electron nuclei formed in the semiconductor are separated due to a potential difference, thereby generating different kinds of electricity in both materials.

There is an electrode on the front and rear of the solar cell, the rear electrode is formed throughout, the front electrode is preferably formed about 5 to 15% of the total area to allow light to pass through. BACKGROUND OF THE INVENTION In the method of forming an electrode in a solar cell, a method of forming an electrode by irradiating a laser beam to a solar cell substrate has recently been utilized for reasons of environmental pollution, miniaturization of electrode width, and the like.

1 is a view for explaining the principle of marking using a laser, Figure 2 is a view for explaining a laser on delay, a laser off delay, a mark delay and a jump delay.

1 and 2, in order to mark the letter "A" using a laser, the letter "A" is divided into a plurality of vectors (11, 12, 13, 14), and each vector (11, 12). Mark the letter " A " while moving the laser beam according to (14).

The letter "A" may be divided into a plurality of mark vectors 11, 12 and 14 and a jump vector 13. The portion corresponding to the mark vectors 11, 12, and 14 is a portion where the actual marking is performed, and the laser beam remains on along the mark vectors 11, 12, and 14. The portion corresponding to the jump vector 13 is a portion that moves between the mark vector 12 and the mark vector 14 without performing actual marking, and the laser beam remains off along the jump vector 13. By various combinations of such mark vectors 11, 12, 14 and jump vectors 13, a desired character or shape can be marked using a laser.

The time taken to mark characters or shapes using a laser includes the delay time due to the inertia of the mechanical drive unit to move the laser beam to a desired position. That is, the phenomenon that the actual position RP at which the laser beam is actually positioned is delayed by operating the driving unit receiving the command signal CS rather than the command position CP by the electric command signal CS transmitted to the driving unit. This happens. In one vector, the laser beam has already reached the end point of the vector at the command position CP, but the laser beam has not yet reached the end point of the vector at the actual position RP. You are in a moving state.

In this way, in consideration of the actual position RP of the laser beam, a waiting time must be set so that the laser beam can substantially reach the end point of the vector. This waiting time is a mark in the mark vectors 11, 12, and 14. It is represented by the delay 17 and is represented by the jump delay in the jump vector 13.

In addition, since the laser beam is moved using the driving unit, a constant velocity section is formed in the central portion of the vector, but an acceleration section is formed at the start point of the vector, and a deceleration section is formed at the end point of the vector. In consideration of such an acceleration period and a deceleration period, a time for which the laser beam waits is set. The waiting time set in the start point of the vector is represented by the laser on delay 15, and the waiting time set in the end point of the vector is Expressed as laser off delay 16.

Therefore, one mark vector 11, 12, 14 includes the waiting time of the laser on delay 15, the laser off delay 16, the mark delay 17, etc., and one jump vector 13 includes a jump time. Waiting time such as delay is included.

3 is a view for explaining an example of a solar cell processing method using a conventional laser, Figure 4 is a view for explaining another example of a solar cell processing method using a conventional laser.

The bus bar line 21 is formed in the solar cell substrate 20 in the longitudinal direction, and the finger line 22 is formed in the direction crossing the bus bar line 21, that is, in the horizontal direction.

Referring to FIG. 3, when the bus bar line 21 and the finger line 22 are formed on the solar cell substrate 20 using a conventional laser, the laser beam is irradiated along the bus bar line 21, and the finger The laser beam is irradiated along the line 22 so that the laser beam is irradiated twice in the overlapping portion 23 where the busbar line 21 and the finger line 22 overlap. In this case, excessive energy is supplied to the overlapping portion 23, thereby damaging the solar cell substrate 20.

Meanwhile, referring to FIG. 4, a method of forming one finger line 22 while alternately repeating the mark vector 26 and the jump vector 27 has been proposed to improve the problem of the method illustrated in FIG. 3. However, as described above, the wait times of the laser on delay 15, the laser off delay 16, the mark delay 17, and the like are included for each mark vector 26, and for each jump vector 27, respectively. There is a problem that a waiting time such as a jump delay is included and the processing time required to form the electrode as a whole increases.

Accordingly, an object of the present invention is to solve such a conventional problem, by minimizing the waiting time included in the vector for moving the laser beam in the process of forming the electrode on the solar cell substrate using a laser, It is to provide a solar cell processing method using a laser that can significantly improve the yield of the work to form the electrode.

In order to achieve the above object, a solar cell processing method using the laser of the present invention comprises a laser for forming a bus bar line and a plurality of finger lines arranged in a direction crossing the bus bar line on a solar cell substrate. A solar cell processing method comprising: a first vector forming step of forming a first mark vector along a line where a bus bar line is to be formed; Forming a bus bar line by irradiating a laser beam along the first mark vector; A second vector forming step of forming a second mark vector along a line where the finger line is to be overlapped with the bus bar line; And a laser on signal for turning on a laser beam, an inactive section for deactivating the laser on signal in a portion overlapping the bus bar line in the second mark vector, and not overlapping the bus bar line in the second mark vector. And a second line forming step of overlapping a second modulation signal having an active period for activating the laser on signal to irradiate a laser beam along the second mark vector and form the finger line. do.

In the solar cell processing method using a laser according to the present invention, preferably, the width or position of the inactive section in the second modulation signal can be changed according to the width or position of the bus bar line.

In the solar cell processing method using a laser according to the present invention, preferably, in the first line forming step, the laser on signal and a first modulation signal for activating the laser on signal in the entire first mark vector. Are superposed on the laser beam along the first mark vector.

In the solar cell processing method using a laser according to the present invention, preferably, in the first line forming step or the second line forming step, a galvano having a motor and a reflection mirror coupled to the rotation axis of the motor. A laser scanner is used to move the laser beam on the solar cell substrate.

According to the solar cell processing method using the laser of the present invention, the yield of the operation of forming the electrode on the solar cell substrate can be improved significantly.

In addition, according to the solar cell processing method using the laser of the present invention, it is possible to prevent damage to the substrate.

In addition, according to the solar cell processing method using a laser of the present invention, it is possible to improve the compatibility that can be processed for a variety of solar cell models.

1 is a view for explaining the principle of marking using a laser,
2 is a diagram for explaining a laser on delay, a laser off delay, a mark delay, and a jump delay,
3 is a view for explaining an example of a solar cell processing method using a conventional laser,
4 is a view for explaining another example of a solar cell processing method using a conventional laser,
5 is a view schematically showing a solar cell processing method using a laser according to an embodiment of the present invention,
FIG. 6 is a view for explaining a laser on signal, a first modulation signal, and a second modulation signal of the solar cell processing method using the laser of FIG. 5.

Hereinafter, embodiments of a solar cell processing method using a laser according to the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 3, an electrode pattern composed of a plurality of lines is formed on the solar cell substrate 20 of the present invention. The electrode pattern is generally a bus bar line 21 in a vertical direction and a bus bar line in a horizontal direction. It consists of a finger line 22 which is arranged in the direction crossing with. Generally, about 2 to 3 busbar lines 21 are formed on one solar cell substrate 20, and about 70 to about 100 finger lines 22 are formed.

In order to form such an electrode pattern using a laser, the laser beam is irradiated onto the solar cell substrate 20 while sequentially moving along each line to form an electrode.

5 is a view schematically showing a solar cell processing method using a laser according to an embodiment of the present invention, Figure 6 is a laser on signal of the solar cell processing method using the laser of Figure 5, the first modulation signal and the first 2 is a diagram for explaining a modulation signal.

5 and 6, the solar cell processing method using the laser according to the present embodiment is to form an electrode pattern on the surface of the solar cell substrate by irradiating a laser beam to the solar cell substrate, the first vector forming step ( 110, a first line forming step 120, a second vector forming step 130, and a second line forming step 140.

In the first vector forming step 110, a first mark vector 31 is formed along the line where the bus bar line 21 is to be formed. The busbar line 21 is formed in the vertical direction on the solar cell substrate 20, and the first mark vector 31 is also formed in the vertical direction in parallel with the busbar line 21.

If the width of the busbar lines 21 to be formed is equal to the spot size of the laser beam, the busbar lines 21 can be formed in one processing. In this case, one first mark vector 31 is formed on one bus bar line 21. However, if the width of the busbar line 21 to be formed is wider than the spot size of the laser beam, the busbar line 21 can be formed through a plurality of repetitive processes. In this case, a plurality of first mark vectors 31 are formed on one bus bar line 21 so as to be spaced apart by the spot size of the laser beam.

In the first line forming step 120, the laser beam is irradiated along the first mark vector 31 to form a bus bar line 21. In the first line forming step 120, a signal in which the laser on signal 41 and the first modulation signal 42 are superimposed is transmitted to a laser irradiator (not shown) to control whether the laser beam is output.

The laser on signal 41 is a signal for turning on the laser beam, and the first modulation signal 42 is a signal for activating the laser on signal in the entire first mark vector 31. Here, "activating the laser on signal" means opening the laser beam emitted from the laser irradiation unit by the laser on signal 41 to irradiate the laser beam to the solar cell substrate 20, and vice versa. Deactivate "means that the laser beam emitted from the laser irradiation unit by the laser on signal 41 is closed so that the laser beam is not irradiated to the solar cell substrate 20.

The bus bar line 21 is formed by irradiating a laser beam on the entire first mark vector 31 by activating the laser on signal 41 in the entire first mark vector 31 by the first modulation signal 42. can do.

In the first line forming step 120, a galvanometer scanner (not shown) is used to move the laser beam along the first mark vector 31.

The galvanometer scanner is configured such that the reflection mirror (not shown) is coupled to the rotation axis of the motor (not shown), so that light incident on the reflection mirror may be irradiated to a desired position by the rotation of the motor. In general, using a pair of galvanometer scanners, the laser beam can be irradiated to a desired position on the solar cell substrate 20. Since the galvanometer scanner has a low mechanical inertia and a short acceleration / deceleration section, the galvanometer scanner has the advantage of obtaining the same processing quality over the entire section in the process of moving the laser beam while irradiating a laser beam of constant power.

In the second vector forming step 130, a second mark vector 32 is formed along the line where the finger line 22 is to be formed. In this case, the second mark vector 32 is disposed in a direction crossing the bus bar line 21 and is formed as a vector while overlapping the bus bar line 21 in a partial region.

The finger lines 22 are formed in the horizontal direction on the solar cell substrate 20, and the second mark vector 32 is also formed in the horizontal direction in parallel with the finger lines 22.

Like the busbar line 21, one second mark vector 32 may be formed according to the width of the finger line 22 to be formed, or a plurality of second mark vectors 32 may be formed.

In the second line forming step 140, the laser beam is irradiated along the second mark vector 32 to form a finger line 22. In the second line forming step 140, a signal in which the laser on signal 41 and the second modulation signal 43 are superimposed is transmitted to the laser irradiator to control whether the laser beam is output.

The second modulation signal 43 includes an active section 44 for activating the laser on signal 41 in a portion of the second mark vector 32 and a laser on signal in another portion of the second mark vector 32. An inactive section 45 for deactivating 41 is included.

Inactive so that the active section 44 is disposed at the portion where the second mark vector 32 and the busbar line 21 do not overlap, and inactive at the portion where the second mark vector 32 and the busbar line 21 overlap. The second modulation signal 43 is configured such that the section 45 is disposed.

Therefore, the laser beam is irradiated to the portion where the second mark vector 32 and the bus bar line 21 do not overlap with the second modulation signal 43, and the second mark vector 32 and the bus bar line 21 are irradiated. ), The finger line 22 may be formed by preventing the laser beam from being irradiated to the overlapped portions.

When the finger line 22 is formed using one mark vector 32 as described above, the electrode processing time can be significantly shortened as compared with the conventional embodiment shown in FIG. 4. In the conventional embodiment of FIG. 4, three mark vectors 26 and two jump vectors 27 are formed to form one finger line 22. The machining time of each mark vector 26 includes waiting times such as laser on delay 15, laser off delay 16 and mark delay 17 in addition to the actual travel time, Machining time also includes waiting time, such as a jump delay, in addition to the actual travel time. As the waiting time increases, the electrode processing time becomes inevitably longer.

However, in the present embodiment, since only one mark vector 32 is formed to form one finger line 22, only the waiting time for one mark vector 32 is included in the machining time. In the portion where the mark vector 32 and the bus bar line 21 overlap, the laser beam is not irradiated onto the solar cell substrate 20 by using an electrical signal for deactivating the laser on signal 41. Therefore, since the waiting time can be significantly reduced, the electrode processing time can be reduced, and damage to the substrate 20 is prevented by preventing the laser beam from being irradiated to the portion where the mark vector 32 and the busbar line 21 overlap. You may.

The width or position of the bus bar line 21 to be formed on the solar cell substrate 20 may be changed according to the model of the solar cell. Accordingly, the width or position of the inactive section 45 in the second modulation signal 43 may also be changed according to the width or position of the busbar line 21.

In the second line forming step 140, a galvanometer scanner is used to move the laser beam along the second mark vector 32.

The solar cell processing method using the laser of the present embodiment configured as described above, by minimizing the waiting time included in the vector for moving the laser beam in the process of forming the electrode on the solar cell substrate by using a laser, The effect which can significantly improve the yield of the operation | work which forms an electrode can be acquired.

In addition, in the solar cell processing method using the laser of the present embodiment configured as described above, by preventing the laser beam is not irradiated to the overlapping portion of the busbar line and the finger line, it is possible to obtain the effect that may damage the substrate have.

In addition, the solar cell processing method using the laser of the present embodiment configured as described above, by configuring the width or position of the inactive section in the second modulation signal, it is possible to perform the processing for various models of solar cells. The effect can be to improve the compatibility.

The scope of the present invention is not limited to the above-described embodiments and modifications, but can be implemented in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the invention claimed in the claims, it is intended that any person skilled in the art to which the present invention pertains falls within the scope of the claims described in the present invention to various extents which can be modified.

20: solar cell substrate
21: busbar line
22: finger line
31: first mark vector
32: second mark vector
110: first vector forming step
120: first line forming step
130: second vector forming step
140: second line forming step

Claims (4)

In the solar cell processing method using a laser for forming a bus bar line on the solar cell substrate, and a plurality of finger lines arranged in the direction crossing the bus bar line,
A first vector forming step of forming a first mark vector along a line where the busbar line is to be formed;
Forming a bus bar line by irradiating a laser beam along the first mark vector;
A second vector forming step of forming a second mark vector along a line where the finger line is to be overlapped with the bus bar line; And
A laser on signal for turning on a laser beam, an inactive section for deactivating the laser on signal in a portion overlapping the bus bar line in the second mark vector, and a portion not overlapping the bus bar line in the second mark vector. And a second line forming step of forming a finger line by irradiating a laser beam along the second mark vector by superimposing a second modulation signal having an active period for activating the laser on signal. Solar cell processing method using laser. The method of claim 1,
According to the width or position of the bus bar line, the width or position of the inactive section in the second modulation signal can be changed, the solar cell processing method using a laser. The method of claim 1,
In the first line forming step,
And a laser beam along the first mark vector by superimposing the laser on signal and a first modulation signal for activating the laser on signal in the entire first mark vector. . The method of claim 1,
In the first line forming step or the second line forming step,
A method of fabricating a solar cell using a laser, comprising: moving a laser beam on the solar cell substrate using a galvanometer scanner having a motor and a reflecting mirror coupled to a rotating shaft of the motor.

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