TWI450409B - Printing machine for printing the electrodes of a solar cell and solar cell manufacturing method - Google Patents

Description

Solar cell electrode screen printing machine and solar cell manufacturing method

The present invention relates to a method of fabricating a solar cell, and more particularly to a method of fabricating a solar cell that reduces the yield loss caused by the step of printing the electrode structure.

Figure 1A shows a cross-sectional view of a conventional solar cell. As shown in FIG. 1A, the solar cell 100 includes a twinned substrate 110, an anti-reflective layer 120, a separation trench 140, and an electrode structure 130. The twin substrate 110 includes an N-type region 111 and a P-type region 112 interconnected. The electrode structure 130 includes an upper electrode 131 penetrating the anti-reflection layer 120 and electrically connecting the N-type region 111; and a lower electrode 132 electrically connecting the P-type region 112.

The method for forming the electrode structure 130 mainly includes the following steps: printing a first conductive paste pattern on the upper surface 113 of the twin crystal substrate 110 by using a printing technique; and printing a second conductive paste pattern on the twin crystal substrate by using a printing technique The lower surface 114 of the 110; and the twin crystal substrate 110 formed with the first conductive paste pattern and the second conductive paste pattern are sintered through a sintering furnace, so that the first conductive paste pattern and the second conductive paste pattern After being sintered, the upper electrode 131 and the lower electrode 132 are formed, respectively.

When performing the printing step, referring to FIG. 2A, the twinned substrate 110 is transferred to the input port 212 of the solar cell electrode screen printing machine 200 by a conveyor belt 211, and the twinned substrate 110 is fed into the solar cell electrode from the input port 212. The screen printing machine 200 is internal. Referring to FIGS. 2B and 2C, the twinned substrate 110 is placed on a stage 201 of the solar cell electrode screen printing machine 200, and a screen is disposed on the twin substrate 110 at a predetermined distance. Further, the conductive paste 205 is poured into one end of the screen, and a strip-shaped scraper 204 is advanced in the traveling direction D1 to apply pressure to the conductive paste 205 on the screen 203. Since the screen 203 has an electrode pattern mesh 207 which is capable of transmitting the conductive paste 205, and the screen 203 is not part of the electrode pattern mesh 207, the conductive paste 205 is not transmitted. Therefore, the conductive paste 205 can penetrate the electrode pattern mesh 207, and the upper electrode 131 or the lower electrode 132 can be formed on the twin substrate 110.

However, according to the conventional manufacturing method, the line of the electrode structure 130 may be incomplete or defective. In addition, since the blade 204 applies pressure to the twinned substrate 110, the twinned substrate 110 may be broken or the mesh 203 may be damaged. There is a need for a solar cell manufacturing method that can reduce the yield loss caused by the steps of printing electrode structures.

It is an object of an embodiment of the present invention to provide a method of fabricating a solar cell that reduces the yield loss caused by the steps of printing the electrode structure.

According to an embodiment of the invention, a solar cell manufacturing method is provided which comprises the following steps. A twinned substrate is provided, and the twinned substrate has a first type region and a second type region on opposite sides of the first type region. Passing a gas stream through at least one of the first type region and the second type region, and printing a conductive paste on the at least one of the first type region and the second type region blown by the airflow by using a printing technique, thereby An electrode structure is formed.

In accordance with an embodiment of the present invention, a solar cell electrode screen printing machine is provided that is adapted to receive a twinned substrate from a conveyor belt. The twin crystal substrate has a first type region and a second type region on the opposite side of the first type region. The solar cell electrode screen printing machine comprises an air knife device and an input port. The air knife device is used to blow a gas stream and blow the gas stream through the twinned substrate. The input port is disposed at the downstream of the air knife device on the conveyor belt, so that the twinned substrate blown by the airflow passes through to feed the twinned substrate into the interior of the solar cell electrode screen printing machine.

In one embodiment, the solar cell electrode screen printing machine further includes a pair of bit devices. The alignment device is configured to correct the position of the twinned substrate that is blown by the airflow for the solar cell electrode screen printing machine to correctly print an electrode structure on the twinned substrate.

In one embodiment, the air knife device includes a draft tube for introducing airflow, and is elongated and extending along a long axis. Preferably, the major axis direction is substantially perpendicular to the direction of travel of the twinned substrate. In an embodiment, the draft tube defines an air inlet aperture and a plurality of air outlet apertures. The air inlet hole is disposed at a first end of the air guiding tube for the airflow to flow into the air guiding tube. The air outlet is used for airflow from the inside of the air guiding tube. In one embodiment, the air outlets include a first air outlet and a second air outlet, and the distance between the first air outlet and the air inlet is smaller than the distance between the second air outlet and the air inlet, and The area of one of the air outlets is smaller than the area of the second air outlet. Preferably, the ratio of the area of the first air outlet to the second air outlet is equal to the ratio of the distance between the first air outlet and the first air inlet and between the second air outlet and the first air inlet.

According to an embodiment of the invention, before the printing of the electrode structure, a wind device is used to generate a gas flow, and the air flow is blown over the surface of the twin crystal substrate to blow foreign matter away from the surface of the twin crystal substrate, thereby reducing the screen. Damage and the opportunity to break the twinned substrate further enhance the production yield of solar cells.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein. The above and other objects, features, and advantages of the invention will be apparent from

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

3 is a schematic view showing an input port portion of a solar cell electrode screen printing machine according to an embodiment of the present invention. As shown in FIG. 3, a solar cell electrode screen printing machine 200 according to an embodiment of the present invention is adapted to receive a twinned substrate 110 from a conveyor belt 211, wherein the twinned substrate 110 has an N-type region 111 and is located A P-type region 112 on the opposite side of the N-type region 111. The solar cell electrode screen printer 200 includes an air knife device 213 and an input port 212. The air knife device 213 is for blowing a gas stream S and blowing the air stream S through the twin crystal substrate 110. The input port 212 is disposed at the downstream of the air knife device 213 of the conveyor belt 211, so that the twinned substrate 110 blown by the airflow S passes through to feed the twinned substrate 110 into the solar cell electrode screen printing machine 200. .

In an embodiment, the solar cell electrode screen printer 200 may further include a pair of bit devices 214. The alignment device 214 is configured to correct the position of the twinned substrate 110 blown by the airflow S for the solar cell electrode screen printing machine 200 to correctly print an electrode structure 130 on the twinned substrate 110. Since the position of the twinned substrate 110 may be slightly offset after being blown by the airflow S, it is preferable to provide the alignment device 214 at the downstream of the input port 212 of the conveyor belt 211, so that the position can be increased. The accuracy of the printed electrode structure 130.

In one embodiment, the air knife device 213 includes a draft tube 301. 4 is a schematic view showing a side of a draft tube having a plurality of air outlets according to an embodiment of the present invention. As shown in FIG. 4, the draft tube 301 is used to open the airflow S, and is elongated and extends in a long axis direction D3. The long axis direction D3 is substantially perpendicular to the traveling direction D1 of the twin crystal substrate. The draft tube 301 defines a first air inlet hole 311 and a plurality of air outlet holes 313. The first air inlet hole 311 is disposed at a first end of the air guiding tube 301 for the airflow S to flow into the air guiding tube 301. A plurality of air outlets 313 are provided for the airflow S to be blown out of the inside of the air guiding tube 301. In FIG. 3 and FIG. 4, five are taken as an example, and the present invention does not limit the number of the air outlets 313.

In one embodiment, the air outlets 313 include a first air outlet 313a and a second air outlet 313b. The distance H1 between the first air outlet 313a and the first air inlet 311 is smaller than the distance H2 between the second air outlet 313b and the first air inlet 311. Since the portion of the draft tube 301 that is farther away from the first air inlet hole 311 has a smaller air pressure, the area of the first air outlet hole 313a is made smaller than the air flow S so that the air flow S uniformly flows out from the inside of the air guiding tube 301 to the outside. The area of the second air outlet 313b. Preferably, the area ratio of the first air outlet 313a and the second air outlet 313b is equal to between the first air outlet 313a and the first air inlet 311 and between the second air outlet 313b and the first air inlet 311. Distance ratio H1/H2.

In an embodiment, the draft tube 301 can further define a second air inlet 312. The second air inlet hole 312 is disposed at a second end of the air guiding tube 301 opposite to the first end for flowing the airflow S into the air guiding tube 301. Thereby, the area of the air outlet 313 closest to the first air inlet hole 311 or the second air inlet hole 312 can be avoided; and the area of the air outlet hole 313 farthest from the first air inlet hole 311 or the second air inlet hole 312, The difference between the two is too large, and the airflow S can be more uniformly discharged and uniformly blown toward the twinned substrate 110, thereby preventing the offset of the twinned substrate 110 from being excessively large. In addition, the amount of airflow of the draft tube 301 can be adjusted according to the distance between the draft tube 301 and the twinned substrate 110 or the angle of the airflow S to the twinned substrate 110 to avoid affecting the transmission of the twinned substrate 110. Actions, such as avoiding skew or falling out of the scene. Preferably, the air flow S is blown from the input port 212 to the outside of the solar cell electrode screen printing machine 200.

FIG. 5 is a flow chart showing a method of fabricating a solar cell according to an embodiment of the present invention. As shown in FIG. 5, a solar cell manufacturing method according to an embodiment of the present invention includes the following steps.

Step S02: providing a twinned substrate 110, and the twinned substrate has an N-type region 111 and a P-type region 112 on the opposite side of the N-type region 111.

Step S04: blowing a gas stream S through at least one of the N-type region 111 and the P-type region 112, and printing a conductive paste 205 on the N-type region 111 and the P-type region 112 blown by the airflow S by a printing technique. The at least one of them forms an electrode structure 130.

As shown in FIG. 2B, when the printing of the electrode structure 130 is performed, the blade 204 is pressed downward to apply pressure to the conductive paste 205 on the screen 203. When a foreign matter adheres to the surface of the twinned substrate 110, the mesh 203 is easily broken by the urging force of the blade 204, and the twinned substrate 110 is broken. Therefore, in the present embodiment, before the printing of the electrode structure 130 is performed, a wind power device 213 is used to generate the air flow S, and the air flow S is blown over the surface of the twin crystal substrate 110 to blow foreign matter away from the surface of the twin crystal substrate 110. The damage of the screen 203 and the chance of the twinned substrate 110 being broken can be reduced, and the production yield of the solar cell 100 can be further improved.

Figure 6 is a flow chart showing the steps of forming an electrode structure of the embodiment of Figure 5. As shown in FIG. 6, more specifically, step S04 of FIG. 5 may include the following steps in an embodiment.

Step S41: A first airflow S1 is blown through the N-type region 111.

Step S42: Printing a silver paste onto the N-type region 111 blown by the first gas stream S1 by a printing technique to form a first electrode 131. As shown in FIG. 7A, the first electrode 131 includes a bus bar wiring 131a and a finger electrode 131b.

Step S43: Turning the twin substrate 110 so that the P-type region 112 faces upward.

Step S44: A second airflow S2 is blown through the P-type region 112.

Step S45: Printing a silver aluminum paste onto the P-type region 112 blown by the second gas stream S2 by a printing technique to form a bus bar wiring 132a of the second electrode 132, as shown in FIG. 7B.

Step S46: A third airflow S3 is blown through the P-type region 112 in which the bus bar wiring 132a is formed.

Step S47: Printing an aluminum paste onto the P-type region 112 blown by the third gas stream S3 by a printing technique to form a back electrode 132b of the second electrode 132, as shown in Fig. 7B.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

100. . . Solar battery

110. . . Twin crystal substrate

111. . . N-type area

112. . . P-type area

113. . . Upper surface

114. . . lower surface

120. . . Antireflection layer

130. . . Electrode structure

131. . . First electrode

132. . . Second electrode

140. . . Separation ditch

200. . . Solar cell electrode screen printing machine

201. . . Workbench

203. . . Screen

204. . . scraper

205. . . Conductive paste

207. . . Electrode graphic mesh

211. . . conveyor

212. . . Input port

213. . . Air knife device

214. . . Alignment device

301. . . Draft tube

311. . . First intake hole

312. . . Second intake hole

313. . . Vent

313a. . . First vent

313b. . . Second vent

321. . . Bus bar wiring

322. . . Back electrode

Figure 1 shows a cross-sectional view of a conventional solar cell.

2A shows a schematic diagram of the transfer of a twinned substrate to an input port of a solar cell electrode screen printer using a conveyor belt.

2B shows a side view of printing an electrode structure onto a twinned substrate in a solar cell electrode screen printer.

2C shows a top plan view of printing an electrode structure onto a twinned substrate in a solar cell electrode screen printer.

3 is a schematic view showing an input port portion of a solar cell electrode screen printing machine according to an embodiment of the present invention.

4 is a schematic view showing a side of a draft tube having a plurality of air outlets according to an embodiment of the present invention.

FIG. 5 is a flow chart showing a method of fabricating a solar cell according to an embodiment of the present invention.

Figure 6 is a flow chart showing the steps of forming an electrode structure of the embodiment of Figure 5.

Fig. 7A shows a plan view of a twin crystal substrate in which a first electrode is formed.

Fig. 7B shows a bottom view of a twin crystal substrate in which a second electrode is formed.

Claims (4)

A solar cell electrode screen printing machine adapted to receive a twine substrate from a conveyor belt, the solar cell electrode screen printing machine comprising: a wind knife device for blowing a gas stream and blowing the gas stream through the crucible a crystal substrate, the air knife device includes a flow guiding tube for introducing the air flow, extending in a strip shape and extending along a long axis, the air guiding tube defining: an air inlet hole, disposed in the air guiding tube a first end for the airflow to flow into the flow conduit; and a plurality of air outlets for blowing the airflow from the inside of the draft tube; an input port, the air knife disposed on the conveyor belt Downstream of the device, the twinned substrate that is blown by the airflow passes through to be fed into the interior of the solar cell electrode screen printing machine, wherein the air outlets include a first air outlet and a second air outlet. And a distance between the first air outlet and the air inlet is smaller than a distance between the second air outlet and the air inlet, and an area of the first air outlet is smaller than an area of the second air outlet. The solar cell electrode screen printing machine according to claim 1, further comprising: a pair of position devices for correcting a position of the twin crystal substrate blown by the airflow for the solar cell electrode screen The printing press correctly prints an electrode structure on the twinned substrate. The solar cell electrode screen printing machine of claim 1, wherein the long axis direction is substantially perpendicular to a traveling direction of the twin crystal substrate. The solar cell electrode screen printing machine of claim 1, wherein an area ratio of the first air outlet to the second air outlet is equal to between the first air outlet and the first air inlet, and The ratio of the distance between the second air outlet and the first air inlet.