Sintering structure for reducing infrared attenuation based on LECO slurry

Abstract

The utility model discloses a sintering structure for reducing infrared attenuation based on LECO slurry, which belongs to the technical field of photovoltaic power generation, and comprises a silicon wafer, a plurality of silver-silicon alloy layers and a plurality of silver electrode grid lines, the silicon wafer is provided with a plurality of V-shaped grooves, the length of each groove is 160nm-190mm, the width of each groove is 12mum-18mum, the depth of each groove is 1mum-1.5 mum, the distance between two adjacent grooves is 0.5-1.5 mum, and the thickness of each groove is 0.5-1.5 mum. The groove is engraved by a laser tool, one silver-silicon alloy layer completely covers the inner surface of one groove, one silver electrode grid line is arranged on one silver-silicon alloy layer, the groove is engraved in the surface of the silicon wafer, the contact area between the LECO slurry and the surface of the battery piece during sintering is increased, and the more the LECO slurry and the silicon wafer form the silver-silicon alloy, the more the LECO slurry and the silicon wafer form the silver-silicon alloy. The more the stable state is, the stronger the anti-attenuation capability is, while the groove can increase the number of the silver-silicon alloy layer during sintering, can reduce the attenuation caused by infrared radiation during welding, further improves the power of the assembly, reduces the series resistance, and achieves the improvement of the efficiency.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic power generation, and in particular relates to a sintering structure based on LECO slurry for reducing infrared attenuation. Background Art

[0002] With the increasing shortage of fossil energy and the increasingly prominent environmental pollution, the problems brought about by climate warming are becoming more and more serious. The sustainable development of new pollution-free energy combustion projects has been widely and deeply studied in various countries.

[0003] Solar cells are effective tools that use the photovoltaic effect to convert light energy into electrical energy. Therefore, they have also developed rapidly in recent years, and the photoelectric conversion efficiency of solar cells has also been greatly improved. With the advancement of technology, the mainstream of solar cells on the market has gradually transitioned from PERC single crystal cells to N-type TOPcon cells. In order to pursue further improvement in the photoelectric conversion efficiency of cells, the market has gradually used LECO (laser enhanced contact optimization) sintering technology to replace traditional sintering technology to sinter N-type TOPcon cells. Traditional sintering technology has a maximum process temperature of more than 700°C, which damages the cell and increases metal induced recombination, thereby reducing the open circuit voltage and overall cell efficiency. Using LECO as a post-sintering treatment reduces the contact sintering temperature, thereby achieving higher open circuit voltage and higher fill factor values ​​on TOPcon solar cells.

[0004] However, when silver-aluminum paste is currently used for sintering, due to the different reaction rates between Ag and Si, and Al and Si, at the same temperature, the reaction and combination rate of Al and Si is faster than that of Ag. Therefore, LECO sintering technology has developed a silver paste that can meet the use requirements to replace the traditional silver-aluminum paste.

[0005] However, when welding silicon wafers to electrodes, the silver paste currently used will form a metastable state during sintering, and under the influence of infrared, problems such as poor contact and large attenuation will occur, resulting in lower battery efficiency and thus affecting component power. Utility Model Content

[0006] In order to solve the problems raised in the above background technology, the utility model provides a sintering structure based on LECO slurry to reduce infrared attenuation, so as to solve the problem that silver paste forms a metastable state during sintering and has poor contact and large attenuation under the influence of infrared.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A sintered structure based on LECO slurry to reduce infrared attenuation, comprising:

[0009] A silicon wafer; a plurality of grooves are provided on the silicon wafer;

[0010] Multiple layers of silver-silicon alloy; one layer of silver-silicon alloy is disposed in a groove;

[0011] A plurality of silver electrode grid lines; a silver electrode grid line is arranged on a silver-silicon alloy layer.

[0012] Preferably, a silver-silicon alloy layer completely covers the inner surface of a groove.

[0013] Preferably, the groove is a "V"-shaped groove.

[0014] Preferably, the groove has a length of 160 nm-190 mm, a width of 12 um-18 um, and a depth of 1 um-1.5 um.

[0015] Preferably, the distance between two adjacent grooves is between 0.5-1.5 um.

[0016] Preferably, the grooves are carved by a laser tool.

[0017] Compared with the prior art, the beneficial effects of the utility model are:

[0018] The present application carves grooves on the surface of the silicon wafer, increasing the contact area between the LECO slurry and the surface of the battery cell during sintering. The more silver-silicon alloy is formed by the LECO slurry and the silicon wafer, the more stable the state is and the stronger the anti-attenuation ability is. The grooves of the present application can increase the silver-silicon alloy layer during sintering, reduce the attenuation caused by infrared radiation during welding, further increase the power of the component, reduce the series resistance, and achieve efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the specific structure of this application;

[0020] Figure 2 Schematic diagram of the conventional LECO slurry sintering structure;

[0021] Figure 3 This is a comparison chart of electrical performance parameters;

[0022] Figure 4 This is a comparison chart of attenuation data;

[0023] The markings in the figure are:

[0024] 1-silver electrode grid line; 2-silicon wafer; 3-silver silicon alloy layer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] Embodiment 1:

[0027] like Figure 1 As shown, a sintered structure based on LECO slurry to reduce infrared attenuation includes:

[0028] Silicon wafer; a plurality of grooves are arranged on the silicon wafer, and the grooves are "V"-shaped grooves. The "V"-shaped grooves can increase the contact area between the silicon wafer and the silver electrode grid line while ensuring that the silver electrode grid line does not completely fall into the groove. According to the common sizes of the silicon wafer and the silver electrode grid line, the length of the groove is 160nm-190mm, the width is 12um-18um, the depth is 1um-1.5um, and the distance between two adjacent grooves is between 0.5-1.5um. The grooves are carved by a laser tool, and the laser carving can prevent impurities from adhering to the grooves and affecting the resistance;

[0029] Multiple layers of silver-silicon alloy; one layer of silver-silicon alloy completely covers the inner surface of a groove;

[0030] A plurality of silver electrode grid lines; a silver electrode grid line is arranged on a silver-silicon alloy layer.

[0031] In this embodiment, the present application carves grooves on the surface of the silicon wafer, thereby increasing the contact area between the LECO slurry and the surface of the battery cell during sintering. The more silver-silicon alloy is formed by the LECO slurry and the silicon wafer, the more steady states there are and the stronger the anti-attenuation ability is. The grooves of the present application can increase the silver-silicon alloy layer during sintering, reduce the attenuation caused by infrared radiation during welding, further increase the power of the component, reduce the series resistance, and achieve efficiency improvement.

[0032] The process of manufacturing a battery cell including the structure of the present application is as follows:

[0033] 1. The original N-type silicon wafer undergoes a texturing process and double-sided texturing to form a pyramid-shaped velvet surface;

[0034] 2. The silicon wafer after texturing is subjected to a laser process, using a nanosecond laser with a power of 4-10W and a pulse repetition frequency. The laser scanning is performed at a speed of 450-600 mm / s to engrave laser grooves under the front grid lines;

[0035] 3. Boron diffusion is carried out in a high-temperature diffusion furnace to form a P-type semiconductor on the front side, forming a PN junction with a square resistance range of 320-450 ohms;

[0036] 4. The chain cleaning machine cleans the BSG on the back, and the tank machine polishes the back;

[0037] 5. Generate a tunneling layer and a polysilicon doped layer on the back through PECVD. The deposition film thickness ranges from 70-150nm;

[0038] 6. Use high temperature tubular annealing furnace to activate doping atoms and improve crystallization rate. The square resistance range is 20-60 ohms;

[0039] 7. Use chain cleaning machine and tank cleaning machine to remove the front wrap and mask layer;

[0040] 8. Use ALD equipment to deposit 2-7nm aluminum oxide on the front side;

[0041] 9. Deposit the front silicon nitride anti-reflection film layer by PECVD. The film thickness is 60-100nm;

[0042] 10. Deposit the silicon nitride anti-reflection film on the back through PECVD. The film thickness is 60-100nm;

[0043] 11. Screen print the silver paste on the front and back sides to form the metal grid lines on the front and back sides to transmit current;

[0044] 12. Finally, ohmic contact is formed through light injection equipment and laser sintering technology.

[0045] The manufactured battery cell including the structure of the present application is connected with Figure 2 The test data of the conventional LECO slurry sintered structure cell is compared as shown below:

[0046] From the electrical performance parameters, such as Figure 3 As shown, the present application is compared with the control column of conventional LECO slurry sintering as an experimental column. It can be seen that the gain of Eta mainly comes from the increase of FF and the decrease of Rser.

[0047] From the contrast attenuation table, we can see that Figure 4 As shown, the average attenuation rate of the experimental example including the structure of the present application is reduced.

Claims

1. A sintered structure based on LECO slurry to reduce infrared attenuation, characterized in that: include: A silicon wafer; a plurality of grooves are provided on the silicon wafer; Multiple layers of silver-silicon alloy; A silver-silicon alloy layer is disposed in a groove; A plurality of silver electrode grid lines; a silver electrode grid line is arranged on a silver-silicon alloy layer.

2. A sintered structure for reducing infrared attenuation based on LECO slurry according to claim 1, characterized in that: A layer of silver-silicon alloy completely covers the inner surface of one groove.

3. A sintered structure for reducing infrared attenuation based on LECO slurry according to claim 1, characterized in that: The groove is a "V" shaped groove.

4. A sintered structure for reducing infrared attenuation based on LECO slurry according to claim 1, characterized in that: The length of the groove is 160nm-190mm, the width is 12um-18um, and the depth is 1um-1.5um.

5. A sintered structure for reducing infrared attenuation based on LECO slurry according to claim 1, characterized in that: The distance between two adjacent grooves is between 0.5-1.5um.

6. A sintered structure for reducing infrared attenuation based on LECO slurry according to claim 1, characterized in that: The grooves are carved by a laser tool.

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