CN115302112A - A femtosecond laser high-efficiency non-destructive precision scribing method and device for solar cells - Google Patents

Abstract

The invention provides a femtosecond laser high-efficiency, non-destructive and precise scribing method and device for solar cells. The device includes a power supply, a circuit controller, a laser generating and focusing unit, a workpiece suction unit, an air extraction unit, and an inert auxiliary unit. Air blower. The invention adopts the femtosecond laser to perform micro-grooving on the solar cell, the scribing is more accurate, the groove wall surface is smooth and clean, and there is no thermal influence, stress, deformation and micro-cracks. The air in the holes of the vacuum suction cup array is pumped out through the suction unit to form a partial vacuum, and the thin and brittle solar cells are firmly adsorbed on the mobile suction platform. An inert auxiliary airflow axial blowing device is set up to instantly blow off the laser-ablated workpiece waste during the femtosecond laser scribing process, reducing the barrier effect of the ablation waste and photoplasma on the incident laser, and avoiding oxidation. Therefore, the purpose of efficient and non-destructive precision dicing of solar cells by femtosecond laser is realized.

Description

A femtosecond laser efficient non-destructive precision scribing method for solar cells and device

technical field

The present invention relates to the field of photovoltaic new energy and laser processing, and in particular to a femtosecond laser high-efficiency, non-destructive and precise scribing method and device for solar cells, which can meet the high-efficiency, non-destructive and precise scribing of various solar cells by femtosecond lasers micromachining.

Background technique

Solar energy is an inexhaustible renewable energy source. Solar photovoltaic cells are environmentally safe, not easy to damage, long life, high reliability, low cost, more and more applications in communications, transportation, national defense, aerospace, petroleum, marine, medical equipment, instrumentation, meteorology, agriculture and daily life The wider it is, it is especially suitable for some unattended special environments and occasions.

The solar panel is the core part of the photovoltaic power generation system. The anti-reflection film coating on the panel is a layer of material with low light reflectivity. The semiconductor structure inside the panel is the key structure of photovoltaic power generation. Efficient and non-destructive precision scribing of solar cells is a key process for manufacturing solar panels. However, the material of solar cells is mainly brittle monocrystalline silicon, polycrystalline silicon or amorphous silicon, and the thickness is very thin (generally no more than 200 microns). During the scribing process, it is necessary to precisely control the width and depth of the micromachining of the scribing groove. And it is required that the battery sheet cannot be cut directly. Therefore, traditional mechanical clamping and scribing methods cannot meet the stringent requirements of micromachining for precision scribing of solar cells.

Laser scribing has the advantages of high efficiency, high precision, non-contact processing, no mechanical stress, and no tool loss. Nanosecond laser scribing and picosecond laser scribing have been gradually applied in the field of solar panel production. However, the nanosecond laser and picosecond laser will have a thermal impact on the processed microgroove area, resulting in thermal stress, resulting in deformation of the solar cell, microcracks are prone to occur in the incision area, and the risk of load on the solar panel increases accordingly. There will also be some imperfections in the surface, and the quality of the cut is limited.

In order to solve the above problems, the present invention provides a femtosecond laser efficient and non-destructive precision scribing method and device for solar cells. In the process of femtosecond laser scribing, taking advantage of the unique advantages of femtosecond laser spot smaller, higher energy density, more accurate scribing, and almost no heat impact, vacuum chucks are used to quickly and easily absorb thin and fragile solar cells. It is supplemented by axial blowing of inert airflow to realize high-efficiency and non-destructive precision scribing of solar cells by femtosecond laser.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a femtosecond laser high-efficiency non-destructive precision scribing method and device for solar cells. The femtosecond laser is used to micro-process the solar cells, the scribing is more accurate, the surface of the groove wall is smooth, and there is no thermal influence, stress, deformation and micro-cracks. The air in the array holes is pumped out through the air pumping unit and the vacuum suction cup to form a partial vacuum, and the thin and brittle solar cells are firmly adsorbed on the mobile suction platform without damage, avoiding the damage caused by the mechanical clamping method to the solar cells Damage, stress and deformation, while ensuring the positional accuracy of femtosecond laser scribing. Through the axial blowing of the inert auxiliary airflow, the laser ablated workpiece waste is immediately blown away, reducing the barrier effect of the ablation waste and photoinduced plasma on the incident laser, and avoiding the oxidation problem during the femtosecond laser scribing process.

The present invention achieves the above-mentioned technical purpose through the following technical means.

A femtosecond laser high-efficiency non-destructive precision scribing device for solar cells includes a power supply, a circuit controller, a laser generation and focusing unit, a workpiece suction unit, an air extraction unit, and an inert auxiliary airflow axial blowing device.

The circuit controller is connected to a power supply, and the machine tool, the air extraction unit and the numerical control platform are all connected to the circuit controller; the circuit controller controls the numerical control platform to regulate and control the laser parameters in the femtosecond laser scribing process, At the same time, the displacement of the laser focusing system and the laser head along the sliding rail and the displacement of the mobile suction platform along the moving sliding rail are precisely adjusted, and the switch of the inert auxiliary air flow is controlled; the switch of the suction unit and the size of the suction force Controlled by the circuit controller; the workpiece suction unit includes two main components: a mobile suction platform and a vacuum suction cup.

The laser focusing system includes a refracting mirror, a focusing lens and an inert auxiliary airflow; the guide air pipe of the inert auxiliary airflow is built into the column of the laser head along the horizontal direction first and then the axial direction; the circuit controller is located on the machine tool On the right side, the CNC platform is located in the right front of the machine tool, and the four support columns are fixed to the bottom of the machine tool through four circular bases and are fixed to the load-bearing workbench through threaded holes.

Preferably, the material of the vacuum suction cup is aluminum alloy, and is fixedly connected to the mobile suction loading platform by welding.

Preferably, the mobile suction platform is located above the load-bearing workbench, and the precise movement in X, Y, and Z directions is carried out by moving the slide rail, and the precise displacement of the vacuum suction cup is controlled by the numerical control platform and the mobile suction platform, so as to It meets the precision displacement requirements of solar cells in all directions during femtosecond laser scribing micromachining.

Preferably, the precise displacement of the laser focusing system and the laser head along the slide rail is realized by a digital control platform controlled by a circuit controller.

Preferably, the solar cells are placed on the workpiece suction unit, the vacuum chuck of the mobile suction platform has an array of small holes, and the air in the array holes is drawn out by the air pumping unit and the vacuum chuck to form a partial vacuum. Adsorb the thin and fragile solar cells intact and firmly on the mobile suction platform.

Preferably, an inert auxiliary airflow blowing device is built in the column of the laser head, and while the femtosecond laser is used to scribe the solar cells, the inert auxiliary airflow is axially blown, and the femtosecond laser scribing Oxidation problems are avoided during the wafering process, while laser ablated workpiece waste is immediately blown off.

Preferably, the suction force of the vacuum chuck is controllable to prevent the solar cells from being damaged due to too much suction, or the solar cells cannot be firmly sucked and fixed due to too small suction.

Beneficial effects of the present invention:

1. In the present invention, femtosecond laser is used to scribing the solar cells, and the micro-machining of the grooves is more precise, without thermal influence and stress, the solar cells will not be deformed, there is no micro-crack in the incision area, and the surface of the groove wall is smooth and clean.

2. The present invention extracts the air in the array holes through the air pumping unit and the vacuum suction cup to form a partial vacuum, and firmly adsorbs the thin and fragile solar cells on the mobile suction platform intact, avoiding the traditional mechanical clamping method The damage, stress and deformation caused to the solar cells, while avoiding the position error caused by the movement of the solar cells during the femtosecond laser scribing process, greatly improves the accuracy of the femtosecond laser scribing.

3. The present invention is equipped with an inert auxiliary airflow axial blowing device, which performs axial blowing of the inert auxiliary airflow while the femtosecond laser scribing, instantly blows off the workpiece waste material ablated by the laser, and reduces the ablation waste material and photoinduced The barrier effect of the plasma on the incident laser light, while avoiding the oxidation problem during the femtosecond laser scribing process.

Description of drawings

FIG. 1 is a schematic structural view of a femtosecond laser efficient non-destructive precision scribing device for solar cells according to the present invention.

Fig. 2 is a schematic structural view of the femtosecond laser focusing and inert auxiliary air blowing device according to the present invention.

In the figure: 1-sliding rail, 2-machine tool, 3-circuit controller, 4-laser focusing system, 5-laser head, 6-vacuum suction cup, 7-mobile suction platform, 8-exhaust unit, 9- Load-bearing workbench, 10-support column, 11-refractor, 12-focus lens, 13-inert auxiliary airflow, 14-solar cell, 15-refractor.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

As shown in Figure 1, a femtosecond laser high-efficiency non-destructive precision scribing device for solar cells according to the present invention includes a slide rail 1, a machine tool 2, a circuit controller 3, a laser focusing system 4, a laser head 5, Vacuum suction cup 6, mobile suction loading platform 7, air extraction unit 8, load-bearing workbench 9 and support column 10. The circuit controller 3 is located on the right side of the machine tool 2, the CNC platform is located at the right front of the machine tool 2, four support columns 10 are fixed on the bottom of the machine tool 2, so that the load-bearing workbench 9 is connected with the machine tool 2, and the mobile suction platform 7 is located Above the table 9, the precise movement of the vacuum chuck 6 during the femtosecond laser scribing process is controlled. The circuit controller 3 is connected to the power supply, the air pumping unit 8 and the numerical control platform are electrically connected to the circuit controller 3, the air pumping unit 8 adjusts the suction force of the vacuum chuck 6, the numerical control platform adjusts the parameters of the laser during the experiment, the movement of the experimental platform and Switch for inert auxiliary gas flow.

When manipulating the workpiece suction unit, as shown in Figure 1, the air in the array holes is sucked out through the suction unit 8 and the vacuum chuck 6 to form a partial vacuum, and the thin and fragile solar cells 14 are firmly adsorbed on the mobile Suction mounting on the platform 7 ensures the positional accuracy of the laser scribing micro-machining, and at the same time avoids damage, stress and deformation of the battery sheet by mechanical clamping.

As shown in FIG. 2 , the femtosecond laser focusing and inert auxiliary air blowing device of the present invention includes a refracting mirror 11 , a focusing lens 12 , an inert auxiliary air flow 13 , a solar cell 14 and a refracting mirror 15 . The light beam generated by the laser enters the refracting mirror 11 after passing through the refracting mirror 15 , and the transmitted light beam passes through the focusing lens 12 to form a focal spot and irradiates on the surface to be processed of the solar cell 14 . The inert auxiliary airflow 13 first enters through the nozzle along the horizontal direction, and then blows axially to the position to be processed on the surface of the solar cell, and immediately blows off the workpiece waste material ablated by the laser during the femtosecond laser scribing process, which significantly reduces the photoinduced The adverse effect of plasma and ablation waste on the incident laser beam avoids the oxidation problem in the process of femtosecond laser scribing, so that the quality and efficiency of femtosecond laser scribing micromachining can be improved at the same time.

A method for using a femtosecond laser efficient and non-destructive precision scribing device for solar cells, comprising the following steps:

The first step is to place the solar cells 14 horizontally on the vacuum suction cup 6 of the mobile suction loading platform 7, start the pumping unit 8, adjust the air valve, and adjust the suction force of the vacuum suction cup 6 to avoid damage to the solar cells due to excessive suction 14. At the same time, ensure that the solar cells 14 are firmly and horizontally mounted on the vacuum chuck 6 .

The second step is to control the numerical control platform, adjust the mobile suction loading platform 7, precisely shift the solar cells 14, and move the position of the workpiece to be processed to the bottom of the laser head 5.

The third step is to turn on the femtosecond laser, adjust the position of the laser head 5 for focusing and tool setting, focus the laser beam to the position to be processed on the surface of the workpiece, turn on the inert auxiliary airflow 13 to blow air in the axial direction, and through the mobile suction The precise displacement of the platform 7 and the laser head 5 performs femtosecond laser precision groove micromachining on the solar battery sheet 14 .

In the fourth step, after the laser scribing is finished, disconnect the power supply, stop the pumping, take out the workpiece, and restore the mobile suction platform 7 and the laser head 5 to the initial position.

The described embodiment is a preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation, without departing from the essence of the present invention, any obvious improvement, replacement or modification that those skilled in the art can make Modifications all belong to the protection scope of the present invention.

Claims (6)

1. The femtosecond laser high-efficiency lossless precision scribing device for the solar cell is characterized by comprising a sliding rail (1), a machine tool (2), a circuit controller (3), a laser focusing system (4), a laser head (5), a vacuum chuck (6), a movable suction platform (7), an air extraction unit (8), a bearing workbench (9), a support column (10), a refractor (11), a focusing lens (12), inert auxiliary air flow (13), a solar cell (14) and a refractor (15).

2. The femtosecond laser high-efficiency lossless precise scribing device for solar cells according to the claim 1, characterized in that the laser focusing system (4) internally comprises a refractor (11), a focusing lens (12), a refractor (15) and an inert auxiliary gas flow (13); the guide air pipe of the inert auxiliary air flow (13) is arranged in the vertical column of the laser head (5) along the direction of first horizontal and then axial.

3. The femtosecond laser efficient lossless precise scribing device for the solar cell slice according to the claim 1, wherein the vacuum chuck (6) is fixedly connected to the movable suction platform (7) through welding, the movable suction platform (7) is positioned above the bearing workbench (9) and performs precise movement in the X, Y and Z directions through a movable slide rail, and the precise displacement of the vacuum chuck (6) is controlled by the numerical control platform and the movable suction platform (7) so as to meet the requirement of precise displacement of the solar cell slice (14) in each direction in the femtosecond laser scribing micromachining process; the precise displacement of the laser focusing system (4) and the laser head (5) along the sliding rail (1) is realized by controlling the numerical control platform by the circuit controller (3).

4. The femtosecond laser high-efficiency lossless precision scribing device for the solar cell piece according to claim 1, wherein a novel femtosecond laser high-efficiency lossless precision scribing method for the solar cell piece is provided, an array small hole is opened on a vacuum chuck (6) of a movable suction platform (7), air in the array small hole is pumped out through an air pumping unit (8) and the vacuum chuck (6) to form a local vacuum, and the thin and fragile solar cell piece (14) is firmly and undamaged and firmly attached to the movable suction platform (7), so that a position error generated by the movement of the solar cell piece (14) in the femtosecond laser scribing process and the damage to the solar cell piece (14) caused by a mechanical clamping method are avoided.

5. The femtosecond laser high-efficiency lossless precision scribing method for the solar cell slice according to claim 4, wherein an inert auxiliary air flow (13) blowing device is arranged in a column of the laser head (5), and when the femtosecond laser is used for grooving and micromachining the solar cell slice (14), the inert auxiliary air flow (13) is blown axially, so that the workpiece waste material ablated by the laser is blown off instantly, and the oxidation problem of femtosecond laser scribing is avoided.

6. The femtosecond laser high-efficiency lossless precise scribing method for the solar cell slice as claimed in claim 4, which is characterized by comprising the following steps:

the method comprises the following steps: horizontally placing the solar cell (14) on a vacuum chuck (6) of a movable suction platform (7), starting an air suction unit (8), adjusting an air valve, regulating the suction force of the vacuum chuck (6), avoiding the damage of the solar cell (14) due to overlarge suction force, and simultaneously ensuring that the solar cell (14) is firmly and horizontally sucked and installed on the vacuum chuck (6);

step two: the numerical control platform is controlled, the movable suction platform (7) is adjusted, the solar cell (14) is precisely moved, and the position to be machined of the workpiece is moved to the position below the laser head (5);

step three: the femtosecond laser device is started, the position of the laser head (5) is adjusted to carry out focusing and tool setting, a laser beam is focused to the position to be processed on the surface of a workpiece, the inert auxiliary air flow (13) is started to carry out axial blowing, and the femtosecond laser precise groove scribing micro-processing is carried out on the solar cell (14) through the precise displacement of the movable suction platform (7) and the laser head (5);

step four: and after the laser scribing is finished, the power supply is disconnected, the air exhaust is stopped, the workpiece is taken out, and the movable suction platform (7) and the laser head (5) are restored to the initial positions.

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