CN108511536A - A kind of back of the body passivation crystal-silicon battery slice backside laser notching construction - Google Patents

Abstract

The invention discloses a laser slotting structure on the back of a passivated crystalline silicon battery sheet, including a battery sheet, the battery sheet includes a laser slotting line and a laser non-slotting area, and a plurality of hollows are opened on the battery sheet, so An electrode is arranged in the hollow, and centipede feet are arranged on the electrode. The laser slotting line is parallel to the hollowing and the laser slotting line does not touch the hollowing. 0.2mm-1.5mm, the upper and lower ends of the hollow are 0.2mm-1.5mm away from the nearest adjacent laser groove line. The invention provides a laser slotting structure on the back of the back passivated crystalline silicon battery sheet, within the limited range of the distance between the hollow place where the electrode is located and the distance between the nearest adjacent laser slotting line, the attenuation power and the number of hidden lobes of the battery assembly can be effectively reduced , Improve the mechanical load capacity of the back passivated crystalline silicon cell.

Description

Laser slotting structure on the back of a passivated crystalline silicon cell

technical field

The invention relates to the technical field of crystalline silicon cells, in particular to a rear passivated crystalline silicon cell backside laser groove structure.

Background technique

With the continuous development of crystalline silicon technology, the expansion of solar cell production scale and the continuous reduction of cell prices, reducing production costs and improving efficiency are the focus of cell technology development. At present, the back passivation battery is widely used because of its obvious efficiency improvement compared with the conventional battery. In the existing production process of the battery sheet, a thin layer of aluminum oxide and a SiNx layer are coated on the back to reduce the number of carrier recombination on the back and improve the open circuit. Voltage; then through laser slotting, the silicon substrate at the slotting place is exposed, and printing makes the aluminum paste contact with the silicon substrate, thereby improving the efficiency of the cell. However, for silicon wafers, laser grooves on the back may cause damage to the crystal structure on the back. The 2mm-5mm warpage of the rear passivated crystalline silicon cell due to the different metal structures on the front and back is caused by warpage stress and laser Under the combined effect of damage, the risk of cracking or breaking of rear passivated crystalline silicon cells will be significantly increased.

At present, the common laser groove structure on the back of passivated crystalline silicon cells is a structure in which the groove line and the hollow are parallel, as shown in Figure 1 of the specification; or a structure in which the groove line and the hollow are perpendicular, as in Figure 2 of the specification, but Since the laser slotting line of this structure directly runs through the entire back of the silicon wafer, there is also a laser slotting line under the back electrode of the cell, so that the rear passivated crystalline silicon cell will have more hidden cracks during the mechanical load test The situation caused the component to fail the test. It was observed that the main hidden crack occurred at the hollowed out position of the electrode. The reason is that there are many ends of the laser slotted line close to the back electrode, especially when the laser slotted line and the hollowed out electrode are perpendicular to each other. Therefore, it is necessary to improve the laser groove structure on the back of the cell to increase the mechanical load capacity of the rear passivated crystalline silicon cell.

In the prior art, the application number is "201720515816.7", a laser slotting structure of emitter and back passivation solar cells. The laser slotting structure of solar cells is composed of laser slotting lines and laser non-slotting areas. The feature is that the laser slotting line is disconnected at the back electrode, a laser non-slotted frame is formed around the back electrode, no slots are made in the back electrode area, and the thermal stress on the back electrode of the battery sheet will not be concentrated and released during component welding In laser groove damage, thus reducing the component welding fragmentation rate.

However, there are still obvious defects in the above structure: the laser slotting line has been slotted all the way to the hollow, and there are many endpoints near the hollow where the back electrode is located, resulting in heavy laser slots around the hollow, and the main hidden cracks of the battery are found by observation. Occurs at the position where the electrode is hollowed out, and the above structure still cannot effectively improve this phenomenon.

Contents of the invention

The object of the present invention is to provide a rear passivated crystalline silicon solar cell rear laser groove structure, so as to solve the problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A laser grooved structure on the back of a passivated crystalline silicon cell, including a cell, the cell includes a laser grooved line and a laser non-grooved area, and a plurality of hollows are opened on the cell, and the hollows are set There are electrodes, centipede feet are arranged on the electrodes, the laser slotting line is parallel to the hollowing out and the laser slotting line does not touch the hollowing out, the left and right ends of the hollowing out are 0.2mm-1.5mm away from the nearest adjacent laser slotting line mm, the upper and lower ends of the hollow are 0.2mm-1.5mm away from the nearest adjacent laser slotting line.

Preferably, the line width of the laser grooved line is 20um-70um.

Preferably, there are multiple laser grooving lines, and two adjacent laser grooving lines are parallel to each other with the same interval, and the distance between the two adjacent laser grooving lines is 0.5mm-1.5mm.

Preferably, the total area of the laser grooved lines accounts for 1%-5% of the surface area of the battery sheet.

Preferably, the area of the hollow is larger than the area of the electrodes and centipede feet.

Compared with prior art, the beneficial effect of the present invention is:

The laser slotting line is parallel to the hollowing and the laser slotting line does not touch the hollowing, so as to avoid the slotting line from opening all the way to the hollowing, which will cause the slotting of the electrode hollowing position to be too heavy, which is prone to hidden cracks, and effectively improves the mechanical performance of the back passivated crystalline silicon cell. Load capacity. Experimental data proves that the use of this slotted structure can make the power attenuation of the cell module not exceed 3.8%, and the number of hidden cracks does not exceed 8 pieces, which can meet the requirements of the mechanical load test.

The invention provides a laser grooved structure on the back of the back passivated crystalline silicon cell, which can effectively reduce the attenuation power of the battery component and the number of hidden lobes within the limited range of the distance between the hollow place where the electrode is located and the distance between the nearest adjacent laser grooved line , Improve the mechanical load capacity of the back passivated crystalline silicon cell.

Description of drawings

Fig. 1 is a schematic diagram of the slotting structure in which the laser slotting line and the hollow phase are parallel in the prior art;

Fig. 2 is a schematic diagram of the slotting structure in which the laser slotting line and the hollowing out are perpendicular to each other in the prior art;

Fig. 3 is a structural diagram of the battery sheet of the present invention;

Fig. 4 is a schematic diagram of the position of the laser groove line, the hollow, and the relative position of the electrodes in the present invention.

In the figure: 1 battery sheet, 2 laser slotted line, 3 laser non-slotted area, 4 hollowed out, 5 electrodes, 6 centipede feet.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to Fig. 1-4, the present invention provides a kind of technical scheme:

A laser grooved structure on the back of a passivated crystalline silicon cell, including a cell 1, the cell 1 includes a laser grooved line 2 and a laser non-grooved area 3, and a plurality of hollows 4 are opened on the cell 1, and the hollows 4 An electrode 5 is arranged inside, and a centipede foot 6 is arranged on the electrode 5. The laser slotting line 2 is parallel to the hollow 4 and the laser slotting line 2 does not touch the hollow 4. The left and right ends of the hollow 4 are far from the nearest adjacent laser slotting line 2 is 0.2mm-1.5mm, and the upper and lower ends of the hollow 4 are 0.2mm-1.5mm away from the nearest adjacent laser slotting line 2. In this case, the component power attenuation of the battery sheet does not exceed 3.8%, and the hidden slivers If the number does not exceed 8 pieces, the module test is qualified. If it is lower than the lower limit of the above range, the power loss of the module will be greater than 3.8%, and the number of hidden cracks is greater than 8 pieces, and the mechanical load test of the module fails; efficiency, resulting in reduced module power.

As a preference, the line width of the laser grooved line 2 is 20um-70um.

As a preference, there are multiple laser grooving lines 2 and two adjacent laser grooving lines 2 are parallel to each other with the same interval, and the distance between two adjacent laser grooving lines 2 is 0.5mm-1.5mm.

As a preference, the total area of the laser grooved line 2 accounts for 1%-5% of the surface area of the battery sheet 1. If the total area of the laser grooved line 2 is low, the aluminum paste cannot be well contacted with the silicon base layer, resulting in a photogenerated current in the solar cell. There is a large resistance in the transmission process, which reduces the efficiency; if the total area of the laser slotting line 2 is large, the effect of passivation of the aluminum oxide layer will be weakened, so that the open circuit voltage does not increase significantly, and the efficiency will also decrease. Therefore, the above-mentioned range limitations are adopted comprehensively.

As a preference, the area of the hollow 4 is larger than the area of the electrodes 5 and centipede feet 6 .

Comparative Experiment:

Select battery sheets with the same size and parameters, and use the traditional laser slot structure on the back of the battery shown in Figure 1 and Figure 2 of the specification and the laser slot structure on the back of the battery shown in Figure 4 of the specification for comparison , to test the mechanical load of the cell assembly, and the test data are shown in Table 1 below:

Table 1

project Attenuation power (%) Number of Hidden Fragments (Pieces) Mechanical load test Traditional Slotted Structure 5.0 10 unqualified Slot structure of the present invention 3.8 8 qualified

According to the data in Table 1, the solar cell backside laser slotting structure of the present invention, compared with the traditional backside laser slotting structure, reduces the attenuation power of the module by 1.2%; the number of hidden cracks is reduced by 20% %.

Compared with the traditional laser slotting structure on the back, the laser slotting structure on the back of the passivated crystalline silicon cell of the present invention adopts the design that the laser slotting line and the hollowing are not in contact, so as to avoid more endpoints of the slotting line where the back electrode is hollowed out , resulting in too heavy slotting at the hollowing out, within the range of the distance between the above hollowing out and the nearest adjacent laser slotting line, it can effectively reduce the attenuation power of the module and the number of hidden cracks, and increase the mechanical load of the cell.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (5)

1. a kind of back of the body is passivated crystal-silicon battery slice backside laser notching construction, including cell piece (1), it is characterised in that：The battery Piece (1) includes laser slotting line (2) and the non-slotted area of laser (3), and multiple hollow outs (4) are offered on the cell piece (1), described It is provided with electrode (5) in hollow out (4), centipede foot (6) is provided on the electrode (5), the laser slotting line (2), which is parallel to, engraves Empty (4) and laser slotting line (2) does not contact hollow out (4), and the left and right ends of the hollow out (4) are away from adjacent nearest laser slotting line (2) 0.2mm-1.5mm, the upper and lower ends of the hollow out (4) are away from adjacent nearest laser slotting line (2) 0.2mm-1.5mm.

2. a kind of back of the body according to claim 1 is passivated crystal-silicon battery slice backside laser notching construction, it is characterised in that：It is described The line width of laser slotting line (2) is 20um-70um.

3. a kind of back of the body according to claim 1 is passivated crystal-silicon battery slice backside laser notching construction, it is characterised in that：It is described Laser slotting line (2) be mutually parallel and be spaced between a plurality of and adjacent two laser slotting lines (2) it is identical, described adjacent two The spacing of laser slotting line (2) is 0.5mm-1.5mm.

4. a kind of back of the body according to claim 1 is passivated crystal-silicon battery slice backside laser notching construction, it is characterised in that：It is described The gross area of laser slotting line (2) accounts for the 1%-5% of cell piece (1) surface area.

5. a kind of back of the body according to claim 1 is passivated crystal-silicon battery slice backside laser notching construction, it is characterised in that：It is described The size of hollow out (4) is more than the size of electrode (5) and centipede foot (6).