CN116329770A - Solar crystalline silicon cell green light ultrafast laser grooving method and system - Google Patents

Abstract

The invention provides a green ultra-fast laser grooving method and a system for a solar crystalline silicon battery, wherein the method comprises the following steps: feeding, laser grooving and blanking; the laser is a green light ultrafast laser capable of emitting high-energy monopulses at a high repetition frequency with high monopulse energy consistency of less than or equal to +/-5%, the high repetition frequency is a certain value between 100KHz and 1MHz, the high-energy monopulse energy is 10uJ-100 uJ. The grooving method realizes grooving by ultra-fast laser vaporization material processing surface with high single pulse energy, almost no heat affected zone appears, and the grooving linewidth can be smaller than 10um.

Description

Solar crystalline silicon cell green light ultrafast laser grooving method and system

Technical Field

The invention relates to the technical field of semiconductor laser processing, in particular to a green light ultrafast laser grooving method and system for a solar crystalline silicon battery.

Background

Solar cells in the current market are classified into three types according to materials: crystalline silicon solar cells, thin film solar cells and photoelectrochemical solar cells. In recent years, the crystalline silicon solar cell has greatly progressed in terms of improving efficiency and reducing cost, and the advantage of the crystalline silicon solar cell in photovoltaics is further improved. In the process of preparing the battery, independent narrow grooves are needed to be carved on the surface of the crystalline silicon battery, each narrow groove corresponds to an independent battery unit, and then the battery units are connected in series to form a solar battery assembly. Compared with the technologies of screen printing, chemical etching and the like, the battery with the buried grid after grooving has the advantages of small contact resistance, high current collection efficiency and high photoelectric conversion efficiency. The laser grooving is non-contact processing, so that no stress is generated, the precision is high, and the micrometer-sized groove can be accurately marked.

At present, the line width of the laser grooving is required to be narrower and narrower, and the technological level is required to be continuously improved to meet the requirement.

Disclosure of Invention

In view of the above, in order to overcome the defects in the prior art, the invention provides a green ultra-fast laser grooving method for a solar crystalline silicon cell, which can realize that the line width of the grooving is smaller than 10um.

The invention provides a green light ultrafast laser grooving method for a solar crystalline silicon cell, which comprises the following steps:

1) And (3) feeding: the solar crystalline silicon battery is conveyed to an operation table below the laser through a feeding conveying mechanism;

2) Laser grooving: ultrafast laser emitted by the laser is focused on the surface of the crystal silicon battery workpiece on the station of the operation table, and grooving of a preset track is completed by controlling the movement of a laser beam X, Y, Z shaft and the advancing speed of the laser beam on the surface of the crystal silicon battery workpiece;

the laser is an ultrafast laser capable of emitting high-energy monopulses at a high repetition frequency and high in monopulse energy consistency, the high repetition frequency is 100KHz-1MHz, the high-energy monopulse energy is 10uJ-100uJ, and the energy difference among monopulses is less than or equal to +/-5%; locking a certain value of the transmitting frequency between 100KHz and 1 MHz;

3) And (3) blanking: and transferring the qualified solar crystalline silicon cells after grooving to other specified positions from the operation table through a blanking conveying mechanism.

Further, the workpiece to be machined is identified and laser focusing is completed through the first vision system between the step 1) and the step 2).

Further, the machined parts are identified through a second vision system between the step 2) and the step 3), and whether the machined parts are qualified or not is judged.

The ultrafast laser emitted by the laser device is amplified in beam size through a shaping optical path, and then is input into a galvanometer grooving module through a beam transmission optical path, and is focused on the surface of a crystalline silicon battery workpiece on a station to finish laser grooving; a dynamic focusing lens is arranged in the galvanometer grooving module, and comprises a scanning galvanometer for controlling the deflection of the laser beam and a field lens for focusing the laser beam; the laser is focused on the surface of the workpiece after passing through the vibrating mirror and the field lens.

Or the ultrafast laser emitted by the laser device is amplified in beam size through a shaping optical path and then is input into a laser cutting head through a beam transmission optical path, and then focused on the surface of the crystalline silicon battery workpiece on the station to complete laser grooving; and a condensing lens group and a high-pressure air nozzle are arranged in the laser cutting head.

Further, the laser is an all-solid-state picosecond laser, and the laser wavelength is 532+/-5 nm.

Further, the single pulse width is 1-10ps.

Further, the light spot of the laser window is 1-3mm, and the divergence angle is 0.5-1.5mrad; the travelling speed of the laser light spot is 1-5000mm/s.

Further, the shaping light path is a beam expanding light path with the magnification of 1-8 times, and the beam transmission light path is formed by a transmission light path with the transmission distance of 10-1000 mm.

Further, the rotation speed of the vibrating mirror is 100-5000 r/s, the field lens is an F-theta field lens or a telecentric field lens, and the focal length is 30-600mm.

Further, the minimum resolution feature size to form the scribe line width is 0.5-10um.

The invention also provides a system for realizing the solar crystalline silicon cell green light ultrafast laser grooving method, which comprises an operation table, an ultrafast laser grooving machine and a controller; the operating platform comprises a base, a rotary table and a driving mechanism, wherein the rotary table and the driving mechanism are arranged on the base, and the driving mechanism can drive the rotary table to rotate; a plurality of stations are arranged on the turntable along the periphery of the turntable, and each station is provided with a vacuum adsorption device for adsorbing the solar crystalline silicon battery; the ultra-fast laser grooving machine supporting device is arranged above the turntable;

the ultrafast laser grooving machine comprises a laser and a light path;

the laser is connected with a computer controller provided with laser grooving system software through a data line, the computer controller inputs the controlled laser power, scanning speed and repetition frequency signals to the laser, and receives pulse synchronous signals of the laser, and simultaneously controls an optical path and an operation table to finish laser grooving on the surface of the crystalline silicon battery workpiece.

Besides the turntable, the invention can also finish grooving by using a one-dimensional linear platform.

The ultra-fast laser of the invention works in such a way that uniform energy is output periodically by single pulse under the locking frequency.

The invention has the beneficial effects that:

1. the ultra-fast laser grooving method based on locking high repetition frequency, single pulse work, high single pulse energy and high single pulse energy consistency can be used for laser grooving on the surface of the crystalline silicon battery, and the linewidth of the grooving is smaller than 10um.

2. The method realizes grooving through ultra-fast laser vaporization material processing surface with high single pulse energy instead of heat-to-melting, so that the phenomena of almost no heat affected zone occurrence, almost no slag hanging, no crack, no edge breakage and the like of the processing surface are avoided. The line width of the grooves is narrower and the material strength is almost unchanged.

3. The high-energy monopulse output by the grooving method provided by the invention is unique in representation in a time domain, the specific position point of the processing surface of the workpiece material during grooving is very accurate, no drift occurs in space, and the grooving quality is very good.

4. The grooving method has the advantages of quick processing time, almost no leakage point or leakage mark, and accurate time sequence matching.

5. Under the irradiation of the ultra-fast laser equipment with high single pulse energy consistency, the invention has good consistency of the optical processing process, the surface of the crystalline silicon battery such as the crystalline silicon battery is clear and bright, the repeated irradiation is not carried out, the material is hardly darkened, and the characteristic parameters of the material are hardly changed.

Description of the drawings:

FIG. 1 is a schematic diagram of an operation principle of a green ultra-fast laser grooving method for a solar crystalline silicon cell according to the present invention;

FIG. 2 is a schematic diagram of another working principle of the method for ultrafast laser grooving of green light of a solar crystalline silicon cell according to the present invention;

FIG. 3 is a schematic diagram of a green ultra-fast laser grooving system for a solar crystalline silicon cell;

FIG. 4 is a photograph showing the effect of the method of the present invention after grooving the surface of the crystalline silicon cell;

wherein: 1. an ultrafast laser; 2. an optical path; 2-1, shaping the light path; 2-2, a beam transmission light path; 3. vibrating mirror; 4. a field lens; 5. a solar crystalline silicon cell workpiece; 6. station, controller, mirror, vibrating mirror grooving module; 10. high-pressure air nozzle, focusing lens group, laser cutting head, base, rotary table, ultrafast laser grooving machine, drive motor, feeding and conveying mechanism, first vision system, and second vision system.

Detailed Description

The method and system for ultrafast laser grooving of green light of a solar crystalline silicon cell provided by the invention are further explained below with reference to the accompanying drawings and specific embodiments, but the invention is not limited to the following embodiments.

The invention provides a green light ultrafast laser grooving method for a solar crystalline silicon cell, which comprises the following steps:

1) And (3) feeding: the solar crystalline silicon cell workpiece 5 is conveyed to an operation table below the laser 1 through a feeding conveying mechanism 18;

2) Laser grooving: ultrafast laser emitted by the laser 1 is focused on the surface of the crystalline silicon battery workpiece 5 on the station 6 of the operation table, and the groove cutting of a preset track is completed by controlling the movement of the axis of the laser beam X, Y, Z and the advancing speed of the laser beam on the surface of the crystalline silicon battery workpiece 5;

the laser 1 is an ultrafast laser capable of emitting high-energy single pulses at a high repetition frequency, wherein the high repetition frequency is 100KHz-1MHz, the high-energy single pulse energy is 10uJ-100uJ, and the energy difference between the single pulses is less than or equal to +/-5%; locking a certain value of the transmitting frequency between 100KHz and 1 MHz;

3) And (3) blanking: and transferring the qualified solar crystalline silicon cell workpiece 5 after grooving to other specified positions from the operation table through a blanking conveying mechanism 17.

As a working principle, the ultrafast laser emitted by the laser 1 amplifies the beam size through the shaping optical path 2-1, and then is input into the galvanometer grooving module 9 through the beam transmission optical path 2-2 to focus on the surface of the crystalline silicon battery workpiece 5 on the station 6 to finish laser grooving; a dynamic focusing lens is arranged in the galvanometer grooving module and comprises a scanning galvanometer 3 for controlling the deflection of the laser beam and a field lens 4 for focusing the laser beam; the laser passes through the galvanometer 3 and then the field lens 4 and is focused on the surface of the workpiece 5. As shown in fig. 1.

The step 2) comprises the following steps:

1. setting laser emission parameters and laser pulse synchronous signals in a level form, and sending the laser pulse synchronous signals and the starting time T1 to a software and hardware controller 7 to serve as processing reference time;

2. debugging a laser beam: the light beam is transmitted through a shaping light path, a light gate and the light beam, wherein the light gate is controlled by TTL level; the software and hardware controller sends a signal for controlling the switch of the software and hardware controller to the optical gate and starts time T2;

3. debugging a vibrating mirror: the software and hardware controller 7 sends a control signal in the form of a 5V high-low level of the vibrating mirror 3 and a starting time T3 to the vibrating mirror 3,

4. the laser beam is debugged, focused near the operation desk through the field lens 4 and works in the effective range of the field lens.

5. The software and hardware controller 7 is controlled by a computer to realize an automatic input/output mode.

6. The content of the ready-to-groove is decomposed by a software and hardware controller to obtain pixels, diameters, filling densities, routing paths and patterns in a readable format, and the boundary range is limited to be not more than the boundary of the area of the laser grooving machine 15.

7. According to the content and sequence of the notch pattern, a laser synchronous signal is input to a software and hardware controller to serve as a time reference, the coordinates of a calibration station serve as a space reference, and a control signal, a time reference, a delay time and a control signal time sequence are transmitted to a vibration mirror, a light gate and a driving motor in sequence through the software and hardware controller to perform integral time sequence calibration and preliminary proofing.

8. And verifying the coincidence degree of the preliminary proofing effect and the preset effect according to the preliminary proofing effect, and if the preliminary proofing effect is different, fine-adjusting the process and parameters of each part until the effect is optimal, locking the parameters and starting grooving.

As another working principle, the ultrafast laser emitted by the laser 1 amplifies the beam size through the shaping light path 2-1, and then is input to the laser cutting head 12 through the beam transmission light path 2-2 to be focused on the surface of the crystalline silicon battery workpiece on the station to complete laser grooving; the laser cutting head is internally provided with a condensing lens group 11 and a high-pressure air nozzle 12. As shown in fig. 2.

The invention also provides a system for realizing the solar crystalline silicon cell green light ultrafast laser grooving method, which comprises an operation table, an ultrafast laser grooving machine 15 and a controller 7; the operation table comprises a base 13, a rotary table 14 and a driving mechanism 16, wherein the rotary table and the driving mechanism are arranged on the base, and the driving mechanism can drive the rotary table to rotate; a plurality of stations 6 are arranged on the turntable along the periphery of the turntable, and each station is provided with a vacuum adsorption device for adsorbing the solar crystalline silicon battery; the supporting device of the ultrafast laser grooving machine 15 is arranged above the turntable 14;

the ultrafast laser router 15 comprises a laser 1 and an optical path 2;

the laser 1 is connected with a computer controller 7 provided with laser grooving system software through a data line, the computer controller 7 inputs the controlled laser power, scanning speed and repetition frequency signals to the laser 1, receives pulse synchronous signals of the laser, and simultaneously controls the optical path 2 and the operating platform to finish laser grooving on the surface of the crystalline silicon cell workpiece 5.

The feeding and conveying mechanism 18 conveys the solar crystalline silicon cell workpiece 5 to the corresponding station 6 on the turntable 14;

the blanking conveying mechanism 17 conveys the grooved solar crystalline silicon cell workpiece out of the corresponding station 6 on the turntable 14.

A first vision system 19 is arranged beside the laser 1 to identify the workpiece to be machined and complete laser focusing.

And a second vision system 20 is arranged above the blanking conveying mechanism 17 to identify the machined parts and judge whether the machined parts are qualified or not.

Example 1:

the laser 1 is connected with a computer 7 provided with laser grooving system software through a data line, the computer 7 inputs the laser power, scanning speed and repetition frequency signals to the laser 1, and the laser is an all-solid-state picosecond laser. The controller receives pulse synchronous signals of the laser and simultaneously controls the light path 2, the galvanometer 3, the field lens 4 and the driving motor 16 to complete grooving.

The laser wavelength is 532+ -5 nm.

Locking the transmitting frequency to be 500KHz; the single pulse energy was 20uJ. The single pulse width was 10ps.

The laser window spot was 2mm and the divergence angle was 1.0mrad.

The shaping light path is a beam expanding light path with 5 times of magnification.

The beam transmission light path is composed of transmission light paths with a transmission distance of 500 mm.

The rotation speed of the vibrating mirror is 1000 revolutions per second.

The field lens is an F-theta field lens, and the focal length is 100mm.

The minimum resolution feature size to form the scribe line width is 2um.

Laser grooving is carried out by using the laser device:

(1) Importing the image to be grooved into a computer;

(2) Reading an image to be grooved through laser grooving system software installed on a computer, and setting laser output power, laser repetition frequency and vibrating mirror working frequency;

and turning on the laser, and scanning by the laser motion control system according to an image signal output by the computer, and carrying out laser grooving on the solar crystalline silicon battery by a high-energy laser beam.

The system structure is shown in fig. 3, and the grooving effect is shown in fig. 4.

Example 2:

substantially the same as in example 1, except that:

the controller receives the pulse synchronization signal of the laser and simultaneously controls the optical path 2, the laser cutting head 12 and the driving motor 16 to complete grooving.

The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, one skilled in the art may make modifications and equivalents to the specific embodiments of the present invention, and any modifications and equivalents thereof without departing from the spirit and scope of the present invention are within the scope of the claims of the present invention.

Claims (10)

1. The green light ultrafast laser grooving method for the solar crystalline silicon battery is characterized by comprising the following steps of:

1) And (3) feeding: the solar crystalline silicon battery is conveyed to an operation table below the laser through a feeding conveying mechanism;

2) Laser grooving: ultrafast laser emitted by the laser is focused on the surface of the crystal silicon battery workpiece on the station of the operation table, and grooving of a preset track is completed by controlling the movement of a laser beam X, Y, Z shaft and the advancing speed of the laser beam on the surface of the crystal silicon battery workpiece;

the laser is an ultrafast laser capable of emitting high-energy monopulses at a high repetition frequency and high in monopulse energy consistency, the high repetition frequency is 100KHz-1MHz, the high-energy monopulse energy is 10uJ-100uJ, and the energy difference among monopulses is less than or equal to +/-5%; locking a certain value of the transmitting frequency between 100KHz and 1 MHz;

3) And (3) blanking: and transferring the qualified solar crystalline silicon cells after grooving to other specified positions from the operation table through a blanking conveying mechanism.

2. The ultra-fast green laser grooving method according to claim 1, wherein the step 1) and the step 2) are performed with a first vision system to identify the workpiece to be machined and complete laser focusing.

3. The ultra-fast green laser grooving method according to claim 1, wherein the second vision system is used for identifying the workpiece between the step 2) and the step 3) to judge whether the workpiece is qualified.

4. The method of claim 1, wherein the laser is an all-solid-state picosecond laser, and the laser wavelength is 532±5nm.

5. The method of ultrafast green laser scribing of claim 1, wherein the single pulse width is 1-10ps.

6. The method of ultrafast green laser grooving according to claim 1, wherein the laser window spot is 1-3mm and the divergence angle is 0.5-1.5mrad; the travelling speed of the laser light spot is 1-5000mm/s.

7. The ultra-fast green laser grooving method according to claim 1, wherein the shaping optical path is a beam expanding optical path with a magnification of 1-8 times, and the beam transmission optical path is a transmission optical path with a transmission distance of 10-1000 mm.

8. The ultra-fast green laser grooving method according to claim 1, wherein the rotation speed of the galvanometer is 100-5000 rpm, the field lens is an F-theta field lens or a telecentric field lens, and the focal length is 30-600mm.

9. The method of claim 1, wherein the minimum resolution feature size to form the scribe line width is 0.5-10um.

10. A system for realizing the green ultra-fast laser grooving method for the solar crystalline silicon cell according to claim 1, which is characterized by comprising an operation table, an ultra-fast laser grooving machine and a controller;

the operating platform comprises a base, a rotary table and a driving mechanism, wherein the rotary table and the driving mechanism are arranged on the base, and the driving mechanism can drive the rotary table to rotate; a plurality of stations are arranged on the turntable along the periphery of the turntable, and each station is provided with a vacuum adsorption device for adsorbing the solar crystalline silicon battery; the ultra-fast laser grooving machine supporting device is arranged above the turntable;

the ultrafast laser grooving machine comprises a laser and a light path;

the laser is connected with a computer controller provided with laser grooving system software through a data line, the computer controller inputs the controlled laser power, scanning speed and repetition frequency signals to the laser, and receives pulse synchronous signals of the laser, and simultaneously controls an optical path and an operation table to finish laser grooving on the surface of the crystalline silicon battery workpiece.

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