TW201448254A - Printing screen and method of manufacturing solar cell by using the same - Google Patents

Abstract

A printing screen and a method of manufacturing a solar cell by using the printing screen are provided. The printing screen comprises a mesh and a blocking layer including a first printing pattern unit. The first printing pattern unit has two linear openings, a central area, and two lateral areas. The central area has a plurality of central openings and a plurality of central blocking portions disposed in a staggered manner between two adjacent ones of the central openings. Each of the lateral areas has a plurality of lateral openings and a plurality of lateral blocking portions disposed in a staggered manner between two adjacent ones of the lateral openings. An orthogonal projection area ratio of the lateral openings of each of the lateral areas to the whole lateral areas is less than an orthogonal projection area ratio of the central openings of the central area to the whole central areas. A bus bar electrode thus formed through the printing screen of the present invention has an excellent welding binding force on a ribbon, thereby improving the reliability of the solar cell.

Description

Printing screen and solar energy using the printing screen Pool manufacturing method

The present invention relates to a screen and a method of manufacturing the same, and more particularly to a screen for printing an electrode of a solar cell, and a method of manufacturing a solar cell using the screen for printing.

A typical solar cell mainly comprises: a substrate for converting light energy into electrical energy, and a front electrode and a back electrode for conducting current. The front electrode includes at least one elongated bus bar electrode and a plurality of finger electrodes laterally connected to the bus electrode. The bus electrode and the plurality of finger electrodes are manufactured by applying a conductive paste to a light receiving surface of the substrate by screen printing, and are cured by a sintering process.

The screen used for printing and molding the front electrode usually comprises a mesh and a barrier layer fixed on the mesh. The barrier layer is patterned and has at least one elongated first opening and a plurality of elongated second openings that connect the first opening. The first opening and the plurality of second openings are available for the conductive paste to pass through The bus electrode and the plurality of finger electrodes are formed.

When the solar cell is completed, a plurality of solar cells and other components are packaged into solar cell modules, and the solar cells must be soldered to the bus electrodes by ribbons, thereby making adjacent cells Electrical connections are made between the solar cells.

It is easy to affect the welding bond between the strip conductor and the bus electrode due to some factors in the soldering operation. For example, the cross-section of the bus electrode formed by screen printing usually forms a central concave structure with a thin central portion and a thicker thickness on both sides. The central concave structure may be in poor contact when soldered to the ribbon. The problem. Specifically, the soldered conductor wire is mainly combined with the two sides of the bus electrode having a relatively high thickness, and is not easily combined with the central portion of the bus electrode having a low thickness to cause an overhead structure, so that the bus electrode and the ribbon conductor are easily caused. Insufficient welding bonding.

In addition, the magnitude of the solder bonding force is also related to the surface roughness of the bus electrode and the size of the area of the bus electrode that can be used for soldering. If the welding force of the welding strip wire and the bus electrode is not good, it is easy to cause the problem of the wire strip falling off when the module is packaged or in the subsequent use, thereby affecting the reliability of the product. Moreover, because the structural design of the screen affects the structural form and surface roughness of the bus electrode formed by screen printing, how to improve the screen structure to produce a bus electrode with a large surface roughness is an important issue.

Therefore, it is an object of the present invention to provide a printing screen for improving the reliability of a product, and a screen for printing using the screen electrode having a printing type which has better welding bonding strength and stability during welding. A method of manufacturing a solar battery.

Thus, the screen for printing of the present invention comprises: a mesh, and a barrier layer fixed to the mesh, the barrier layer comprising: a first ink-dropping pattern unit.

The first ink-dropping pattern unit has two linear openings spaced apart in a first direction, a central region between the two linear openings, and two opposite sides of the two linear openings On the outer side of one side of the central zone. The central zone has a plurality of central openings spaced along the first direction and extending respectively in a second direction to connect the two linear openings, and a plurality of central barriers respectively located between the plurality of central openings. Each of the outer regions has a plurality of outer openings respectively extending from one of the two linear openings away from the linear opening and spaced apart along the first direction, and a plurality of outer openings respectively located in the plurality of outer openings The outer barrier between. The ratio of the orthographic projection area of all the outer openings of each outer zone to the overall outer zone is smaller than the ratio of the orthographic projection area of all central openings of the central zone to the entirety of the central zone.

Preferably, the barrier layer further comprises a second ink-dropping pattern unit connected to the first ink-dropping pattern unit, the second ink-dropping pattern unit comprising a plurality of spaced apart along the first direction and extending respectively in the second direction And a finger opening on an opposite side of the first ink drop pattern unit, wherein the length of each of the finger openings in the first direction is smaller than the length of the first ink drop pattern unit in the second direction.

The method for manufacturing a solar cell of the present invention comprises: providing a substrate; forming an emitter layer on a light receiving surface side of the substrate; The screen for printing prints a conductive paste on the light-receiving surface of the substrate, and the conductive paste passes through the linear opening, the central opening and the outer opening of the first ink-dropping pattern unit of the printing screen, and the light-receiving coating is applied to the light-receiving surface. a bus electrode is formed on the surface; a plurality of finger electrodes are disposed on the light receiving surface of the substrate; and a back electrode is disposed on a back surface of the substrate opposite to the light receiving surface.

The method for manufacturing a solar cell of the present invention comprises: providing a substrate; forming an emitter layer on a light receiving surface side of the substrate; and printing a conductive paste on the light receiving surface of the substrate using a screen for printing as described above; The conductive paste is coated on the light receiving surface by the linear opening, the central opening, the outer opening and the finger opening of the second ink drop pattern unit of the first ink drop pattern unit of the printing screen, and forms a bus electrode and a plurality of finger electrodes connected to the bus electrode; and a back electrode disposed on a back surface of the substrate opposite to the light receiving surface.

The effect of the present invention is that the bus electrode made by using the screen for printing of the present invention has an uneven structure which is arranged along the first direction on the upper surface, and an average thickness of the cross-section of the bus electrode, so that the The welding area of the bus electrode and the ribbon wire can improve the welding bonding strength and stability of the two, thereby improving product reliability.

1‧‧‧Printing screen

11‧‧‧Mesh

111‧‧‧Network cable

12‧‧‧Block

20‧‧‧First ink-dropping pattern unit

21‧‧‧Line opening

22‧‧‧Central District

221‧‧‧Central opening

222‧‧‧Central Block

223‧‧‧Assistance opening

23‧‧‧Outside area

231‧‧‧Outside opening

232‧‧‧Outer barrier

233‧‧‧Connecting opening

24‧‧‧Second ink-dropping pattern unit

241‧‧‧ finger opening

3‧‧‧Substrate

31‧‧‧Stained surface

32‧‧ ‧ emitter layer

33‧‧‧Concurrent electrode

34‧‧‧ finger electrode

35‧‧‧Back

36‧‧‧Back electrode

7‧‧‧Scraper

81‧‧‧First direction

82‧‧‧second direction

83‧‧‧ scraping direction

91~97‧‧‧Steps

L1~L14‧‧‧ length

L13’‧‧‧ length

Other features and effects of the present invention will be apparent from the following description of the drawings. FIG. 1 is a top plan view of one of the first preferred embodiments of the printing screen of the present invention; FIG. Partial enlarged view of 1; 3 is a partial cross-sectional view taken along line AA of FIG. 2; FIG. 4 is a block diagram showing a first step of a method for manufacturing a solar cell using the screen for printing according to the present invention. 5 is a schematic flow chart of one step of the first preferred embodiment; FIG. 6 is a top plan view of a second preferred embodiment of the printing screen of the present invention; FIG. 7 is a partial enlarged view of FIG. Figure 8 is a block diagram showing a second preferred embodiment of a method for manufacturing a solar cell using the printing screen of the present invention; and Figure 9 is a flow chart showing the steps of the second preferred embodiment.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to Figures 1, 2 and 3, a first preferred embodiment of the screen 1 for printing according to the present invention is used for printing a flow electrode on a substrate of a solar cell during the manufacture of a solar cell. The screen 1 for printing comprises: a mesh cloth 11, and a barrier layer 12 fixed to the mesh cloth 11.

The mesh 11 of the present embodiment includes a plurality of interlaced network lines 111. The intersection of any two network lines 111 may be referred to as a mesh node, and the holes formed between the plurality of interlaced network lines 111 may be referred to as Mesh. Of course, the outer periphery of the mesh 11 is also provided with a frame not shown, but since neither the frame nor the mesh 11 is the focus of the present invention, it will not be described.

The material of the barrier layer 12 of the present embodiment is, for example, a photoresist material, and includes a first ink drop pattern unit 20. It should be noted that due to solar energy The number of the bus electrodes of the battery may be one or more, so correspondingly, the barrier layer 12 of the printing screen 1 may be provided with only one first ink-dropping pattern unit 20 or a plurality of first ink-dropping pattern units 20, Can be adjusted according to demand, no need to limit. Hereinafter, for convenience of explanation, one of the first ink-dropping pattern units 20 will be described as an example.

The first ink-dropping pattern unit 20 has two linear openings 21 spaced apart and extending along a first direction 81, a central region 22 between the two linear openings 21, and two of the two are respectively located The outer opening 23 of the linear opening 21 is opposite to the side of the central portion 22. In the present embodiment, the length L1 of each of the linear openings 21 in a second direction 82 perpendicular to the first direction 81 is 100 to 200 μm.

The central portion 22 has a plurality of central openings 221 spaced along the first direction 81 and extending in the second direction 82 respectively, and a plurality of central openings 221 respectively located in the plurality of central openings 221 Central blocking portion 222. In this embodiment, the length L2 of each central opening 221 in the first direction 81 is 60-120 μm, and the length L3 in the second direction 82 is 700-900 μm. The length L4 of each central blocking portion 222 in the first direction 81 is 20 to 30 μm.

Each of the outer regions 23 has a plurality of outer openings 231 spaced apart along the first direction 81, and a plurality of outer blocking portions 232 respectively located between the plurality of outer openings 231. The plurality of outer openings 231 extend from one of the two linear openings 21 away from the linear opening 21, respectively. In this embodiment, the plurality of outer openings 231 extend outward in the second direction 82, and each outer opening 231 is in the first direction. The length L5 on 81 is 20 to 40 μm, and the length L6 in the second direction 82 is 150 to 250 μm. The length L7 of each outer blocking portion 232 in the first direction 81 is 20 to 30 μm.

In addition, all of the outer openings 231 of each of the outer regions 23 of the present embodiment occupy an area of the orthographic projection area of the outer portion 23 as a whole, and are smaller than the ratio of the orthographic projections of all the central openings 221 of the central portion 22 to the entire central portion 22.

Since the printing screen 1 of the present embodiment is an electrode for printing and manufacturing a solar cell, a first preferred embodiment of the manufacturing method of the solar cell of the present invention will be described below, and the printing screen 1 of the embodiment will be described. The effect of the innovative structural design and the numerical significance of the aforementioned length. Referring to Figures 2, 4, and 5, the manufacturing method includes the following steps: Step 91: Providing a substrate 3.

Step 92: An emitter layer 32 is formed on a light receiving surface 31 side of the substrate 3.

Specifically, in this embodiment, the emitter layer 32 is formed on the inner side of the light receiving surface 31 of the substrate 3 by a diffusion process, and the emitter layer 32 forms a pn junction with the substrate 3 to be a photovoltaic. The source of special effects. In addition, an anti-reflection layer (not shown) may be formed on the light-receiving surface 31 by vacuum coating, such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). . Since the material of the substrate 3, the arrangement of the layer body and the detailed structure are not the focus of the present invention, they will not be described, and are simply illustrated in the drawings.

Step 93: Using the printing screen 1 described in this embodiment The light-receiving surface 31 of the substrate 3 is printed on the conductive paste, and the conductive paste is passed through the linear opening 21, the central opening 221, and the outer opening 231 of the first ink-dropping pattern unit 20 of the printing screen 1 to be covered by the light-receiving surface. On the face 31, a heat treatment is performed to form a bus electrode 33.

Specifically, the present embodiment mainly uses a doctor blade 7 to scrape the conductive paste on the printing screen 1 along a scraping direction 83, thereby enabling the conductive paste to pass through the printing screen 1 The ink-receiving pattern unit 20 is disposed on the light-receiving surface 31.

Step 94: A plurality of finger electrodes 34 that connect the bus electrodes 33 are disposed on the light receiving surface 31 of the substrate 3.

Specifically, in this step, the conductive paste is printed on the light-receiving surface 31 of the substrate 3 through another printing screen (not shown), and the conductive paste is covered by the openings of the printing screen. The bus electrodes 33 are connected to the light receiving surface 31, and finally the plurality of finger electrodes 34 are formed by heat treatment. After that, the bus electrode 33 and the plurality of finger electrodes 34 are subjected to heat treatment such as firing. If an anti-reflection layer is formed on the light-receiving surface 31 in step 92, then in step 93. The conductive paste having a penetrating property is generally used to form the bus electrode 33 and the plurality of finger electrodes 34, and during the sintering process, the bus electrode 33 and the plurality of finger electrodes 34 can be The emitter layer 32 is contacted through the anti-reflective layer.

It is further noted that the bus electrode 33 and the conductive paste of the plurality of finger electrodes 34 may be the same or different, and need not be limited. In addition, in practice, the bus electrode 33 and the plurality of finger electrodes 34 are sintered. The heat treatment may be performed separately or sequentially, and the step 94 may be sequentially reversed with the step 93. That is, the forming operation of the plurality of finger electrodes 34 may of course be preceded by the bus electrode 33.

Step 95: A back electrode 36 is disposed on a back surface 35 of the substrate 3 opposite to the light receiving surface 31.

The back electrode 36 cooperates with the bus electrode 33 and the plurality of finger electrodes 34 to output electrical energy generated by the solar cell. However, since the back electrode 36 is not a modification of the present invention, it will not be described here.

It should be noted that the sequence between steps 93 and 95 can be flexibly mobilized, that is, after the plurality of finger electrodes 34 are formed on the light receiving surface 31 of the substrate 3, the printing net of the embodiment is used. The plate 1 forms the bus electrode 33 on the light receiving surface 31. In addition, after the back electrode 36 is formed on the back surface 35, the bus electrode 33 and the plurality of finger electrodes 34 may be formed on the light receiving surface 31, and thus it is not limited to the form disclosed in the embodiment.

It is further illustrated that the present embodiment connects the central region 22 and the two outer regions 23 through the two linear openings 21 extending in the first direction 81, and is electrically conductive during the screen printing process in step 93. After the slurry passes through the two linear openings 21, the plurality of central openings 221 and the plurality of outer openings 231, a bus bar electrode 33 which is formed in a complete and continuous strip shape and extends along the first direction 81 is formed substantially The bus electrode 33 can be prevented from being disconnected to affect the conductive effect. In order to achieve the aforementioned effect, the length L1 of each of the linear openings 21 in the second direction 82 is 100 to 200 μm. If the length L1 is too large, the length L3 of each central opening 221 in the second direction 82 is limited. And the length L6 of each of the outer openings 231 in the second direction 82, thereby affecting the welding tension. On the other hand, if the length L1 is too small, there is a problem that the conductive paste in each of the linear openings 21 is insufficiently printed, which in turn causes the bus electrode 33 to be broken to affect the conductivity.

In addition, the present embodiment provides the plurality of spaced central openings 221 and the plurality of spaced outer openings 231, so in step 93, because of the central blocking portion 222 of the central region 22 and each of the outer regions 23 The outer barrier portion 232 limits the throughput of the conductive paste, that is, the conductive paste can only pass through the central opening 221 of the central region 22 and the outer opening 231 of each outer region 23, the aforementioned design of the confluence of the screen printing The upper surface of the electrode 33 can form a concave-convex structure having high and low undulations and arranged in the first direction 81, which can greatly increase the roughness and surface area of the bus electrode 33. Therefore, when a plurality of solar cells and other components are subsequently packaged into a solar cell module, the roughened bus electrode 33 can increase the soldering area with the ribbon (not shown), thereby improving the relationship between the two. Welding bonding and stability, which in turn improves product reliability.

In order to achieve the aforementioned effect, the length L2 of each of the central openings 221 in the first direction 81 is 60 to 120 μm, and the length L4 of each of the central blocking portions 222 in the first direction 81 is 20 to 30 μm. The length L5 of each outer opening 231 in the first direction 81 is 20-40 μm, and the length L7 of each outer blocking portion 232 in the first direction 81 is 20-30 μm.

When the length L2 or the length L5 is too large, the range of the conductive paste passing through each of the central openings 221 or each of the outer openings 231 is too large, so that the printed electrode 33 of the printed type has its upper surface corresponding to the central region 22 or the number The portions of the outer regions 23 are likely to form a partially flat structure, and thus the uneven structures having high and low undulations and arranged along the first direction 81 cannot be formed, thereby failing to provide sufficient welding bonding force and stability. On the other hand, when the length L2 or the length L5 is too small, the conductive paste is less likely to flow through the plurality of central openings 221 or the plurality of outer openings 231, resulting in the incompatibility of the bus electrodes 33.

In addition, when the length L4 or the length L7 is too large, the plurality of central blocking portions 222 or the plurality of outer blocking portions 232 block the passage of the conductive paste to be too large, and it is also easy to form a partially flat structure and cause the printed type. The upper surface roughness of the bus electrode 33 is insufficient to reduce the welding bonding force and the stability. On the other hand, when the length L4 or the length L7 is too small, the effect of the plurality of central blocking portions 222 or the plurality of outer blocking portions 232 restricting the throughput of the conductive paste is poor, and thus the upper surface of the printed bus electrode 33 is printed. The uneven structure in which the high and low undulations are arranged and arranged in the first direction 81 cannot be formed, thereby reducing the welding bonding force and the stability.

More importantly, in this embodiment, all the outer openings 231 of each outer region 23 occupy the ratio of the orthographic projection area of the outer region 23 as a whole, and less than all the central openings 221 of the central region 22 occupy the entire central region 22. Projected area ratio. Through the foregoing innovative design, in the screen printing process of step 93, the discharge amount of the conductive paste through all the central openings 221 of the central zone 22 is greater than the discharge amount of all the outer openings 231 passing through any of the outer zones 23. Thus, the cross section of the bus electrode which can be overcome by the conventional printing screen tends to form a central concave structure, and when it is welded to the ribbon, it will be overhead and the contact failure will occur. Thus, the printing using the embodiment is used The bus electrode 33 obtained by the screen 1 has an average thickness of the central portion and the both side portions, thereby further increasing the welding area between the bus electrode 33 and the ribbon conductor, and enhancing the welding combination of the two. Force and stability.

In order to achieve the aforementioned effect, the length L3 of each of the central openings 221 in the second direction 82 is 700 to 900 μm, and the length L6 of each of the outer openings 231 in the second direction 82 is 150 to 250 μm. If the length L3 is too small or the length L6 is too large, the amount of discharge of the central portion 22 is too small or the discharge amount of the outer side regions 23 is too large, and the central portion of the printed bus electrode 33 is easily recessed or The thickness of the two sides is relatively high, so that a significant central concave structure is formed on the cross section thereof, which causes a problem of poor contact between the bus electrode 33 and the welding wire. On the other hand, if the length L3 is too large or the length L6 is too small, the two linear openings 21 are oppositely adjacent to both sides of the first ink-dropping pattern unit 20, so that the two linear openings 21 are continuous. Increasing the amount of conductive paste passing on both sides of the first ink-dropping pattern unit 20 in a line shape also causes the printed electrode 33 of the printed type to have a structure in which the center is recessed or both sides are raised.

That is, the linear opening 21 of the present embodiment is disposed between the two outer regions 23 and the central region 22, and is not disposed on the outermost sides of the corresponding bus electrode 33, and cooperates with the plurality of central portions. The size ratio of the opening 221 to the plurality of outer openings 231 is designed to effectively alleviate the problem that the cross-sectional structure of the bus electrode 3 produces a central depression and is convex on both sides.

In summary, the present embodiment transmits a plurality of central openings 221 and a plurality of central blocking portions 222 staggered in the central region 22, and a plurality of outer openings 231 and a plurality of outer blocks arranged in a staggered manner in each of the outer regions 23. The portion 232, the aforementioned innovative structure, causes the upper surface of the printed bus electrode 33 to have a concave-convex structure arranged along the first direction 81, and the welding area of the bus electrode 33 and the ribbon wire can be increased. In addition, in this embodiment, the ratio of the orthographic projection area of all the outer openings 231 of each outer region 23 to the entire outer region 23 is smaller than the ratio of the orthographic projection area of all the central openings 221 of the central region 22 to the entire central region 22. The cross-sectional thickness of the printed bus electrode 33 is made relatively uniform, thereby further increasing the soldering area between the bus electrode 33 and the ribbon conductor. Since the increase of the welding area can improve the welding bonding strength and the stability, thereby improving the reliability of the product, it is indeed possible to achieve the purpose of the invention.

Referring to Figures 6 and 7, a second preferred embodiment of the screen 1 for printing according to the present invention is substantially the same as the first preferred embodiment. The difference between the two is that the barrier layer 12 of the present embodiment includes the In addition to the first ink drop pattern unit 20, a second ink drop pattern unit 24 that connects the first ink drop pattern unit 20 is further included.

The central portion 22 of the first ink-dropping pattern unit 20 further has a plurality of auxiliary openings 223 spaced along the first direction 81 and extending respectively along the second direction 82 to the two linear openings 21, and the auxiliary region 223 The central opening 221 and the central blocking portion 222 of the central portion 22 are a plurality of groups and are respectively located between the plurality of auxiliary openings 223 spaced apart from each other. In addition, each of the outer regions 23 of the first ink-drop pattern unit 20 further has a plurality of connection openings 233 spaced along the first direction 81 and connecting one of the two linear openings 21, and each outer region The outer opening 231 and the outer blocking portion 232 of the pair 23 are a plurality of sets and are respectively located at two or more intervals of the plurality of connections Between the openings 233.

The second ink-dropping pattern unit 24 includes a plurality of finger-shaped openings 241 spaced along the first direction 81 and extending in the second direction 82 respectively on opposite sides of the first ink-dropping pattern unit 20, the plurality of fingers The opening 241 is connected to the plurality of connection openings 233, respectively. In this embodiment, the length L11 of each of the finger openings 241 in the first direction 81 is smaller than the length L12 of the first ink drop pattern unit 20 in the second direction 82, and each of the finger openings 241 is The lengths L13, L13' in the second direction 82 are also smaller than the length L14 of the first ink-dropping pattern unit 20 in the first direction 81.

Referring to Figures 6, 7, 8, and 9, a second preferred embodiment of the method for fabricating a solar cell of the present invention is substantially the same as the first preferred embodiment, and also includes steps 91 and 92, however The difference is that the preferred embodiment further includes steps 96 and 97 subsequent to step 92.

Step 96: using the screen 1 for printing according to the embodiment, the conductive paste is printed on the light-receiving surface 31 of the substrate 3, and the conductive paste is passed through the line of the first ink-dropping pattern unit 20 of the screen 1 for printing. The opening 21, the central opening 221, the outer opening 231, and the finger openings 241 of the second ink drop pattern unit 24 are coated on the light receiving surface 31, and are heat treated to form the bus electrode 33 and the bus electrode 33, respectively. The plurality of finger electrodes 34.

Specifically, the present embodiment also cooperates with the doctor blade 7 to scrape the conductive paste on the printing screen 1 along the scraping direction 83, thereby enabling the conductive paste to pass through the first screen 1 of the printing. Drop ink pattern unit 20 And the second ink drop pattern unit 24 is coated on the light receiving surface 31.

Wherein, the bus electrode 33 is formed by the conductive paste of the first ink drop pattern unit 20, and the plurality of finger electrodes 34 are formed by the conductive paste of the second ink drop pattern unit 24. After that, the bus electrode 33 and the plurality of finger electrodes 34 are subjected to a heat treatment such as sintering. If the anti-reflection layer is formed on the light-receiving surface 31 in step 92, it is usually in step 96. The bus bar electrode 33 and the plurality of finger electrodes 34 are formed using a conductive paste having conductivity, and the bus electrode 33 and the plurality of finger electrodes 34 can pass through the anti-reflection layer during sintering. The emitter layer 32 is contacted.

Step 97: The back electrode 36 is disposed on the back surface 35 of the substrate 3. The order between steps 96 and 97 is interchangeable and is not limited to the examples of the embodiment.

Further, in the embodiment, each of the finger openings 241 is connected through each of the connection openings 233, and the other end of the connection opening 233 is further connected to one of the two linear openings 21, thereby improving subsequent screen printing. The connection between the plurality of finger electrodes 34 and the bus electrode 33 is bonded. In order to achieve the aforementioned effect, the length L8 of each of the connection openings 233 in the first direction 81 is 100 to 300 μm, and the length L9 in the second direction 82 is 150 to 250 μm. When the length L8 is too small, the bonding effect of the printed bus electrode 33 and the plurality of finger electrodes 34 is not good, and the two are easily disconnected to affect the conductive effect. On the other hand, if the length L8 is too large, the number of the outer opening 231 and the outer blocking portion 232 of each outer side region 23 is relatively small, which will affect the upper surface of the bus electrode 33. The roughness and the number of the uneven structures of the upper surface which are arranged along the first direction 81 are reduced, and thus the welding area and bonding force between the portion of the bus electrode 33 which corresponds to the opening 233 and the bonding wire are detrimental.

In addition, since the connection openings 233 of the two outer regions 23 of the present embodiment are the left and right groups and the two pairs are correspondingly located on the opposite sides of each of the auxiliary openings 223, and the conductive paste passes through each of the auxiliary openings 223. The discharge amount needs to be larger than the discharge amount of the two connection openings 233 corresponding thereto, so that the screen-formed bus electrode 33 corresponds to the portion of the auxiliary opening 223 and the connection opening 233 (ie, the bus electrode 33 is connected to the finger electrode 34). The conductive paste is printed in a sufficient amount to ensure a good electrical connection between the bus electrode 33 and the finger electrode 34, and the thickness of the cross section of the aforementioned portion can be averaged to enhance the bonding force with the soldered wire. .

In order to achieve the aforementioned effect, the length L10 of each of the auxiliary openings 223 in the first direction 81 is 150 to 250 μm. When the length L10 is too small, the discharge amount of the plurality of auxiliary openings 223 is too small to cause the central portion of the cross section of the bus electrode 33 to be concave, and the welding lead is overhead to reduce the welding stability between the two, and The connection state of the bus electrode 33 and the finger electrode 34 is not good and the conductive effect is lowered. When the length L10 is too large, the number of the central opening 221 and the central blocking portion 222 of the central portion 22 is relatively small, which will affect the roughness of the upper surface of the bus electrode 33 and cause the upper surface along the first The number of the uneven structures arranged in the direction 81 is reduced, so that the welding area and the bonding force between the portion of the bus electrode 33 corresponding to the auxiliary opening 223 and the welding wire are reduced.

As can be seen from the above description, the screen 1 for printing of the present embodiment The resulting bus electrode 33 is also excellent in solder bonding strength and stability to the ribbon conductor. In addition, since the printing screen 1 of the present embodiment can screen-form the bus electrode 33 and the plurality of finger electrodes 34 at a time, the manufacturing process can be simplified to improve production efficiency, and the device and the device can be reduced. Expenditure on the production line reduces equipment costs.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

1‧‧‧Printing screen

12‧‧‧Block

20‧‧‧First ink-dropping pattern unit

21‧‧‧Line opening

22‧‧‧Central District

221‧‧‧Central opening

222‧‧‧Central Block

23‧‧‧Outside area

231‧‧‧Outside opening

232‧‧‧Outer barrier

81‧‧‧First direction

82‧‧‧second direction

L1~L7‧‧‧ length

Claims (11)

A printing screen comprising: a mesh, and a barrier layer fixed to the mesh, the barrier layer comprising: a first ink-dropping pattern unit having two spaced lines extending in a first direction a central opening, a central region between the two linear openings, and two outer regions respectively located on a side opposite to the central portion of the two linear openings, the central region having a plurality of Arranging at intervals in a direction and extending respectively in a second direction to connect the central openings of the two linear openings, and a plurality of central blocking portions respectively located between the plurality of central openings, each of the outer regions having a plurality of One of the two linear openings extends away from the linear opening and is respectively spaced apart in the first direction, and a plurality of outer blocking portions respectively located between the plurality of outer openings, each The ratio of the orthographic projection area of all the outer openings of the outer zone to the entirety of the outer zone is smaller than the ratio of the orthographic projection area of all the central openings of the central zone to the entirety of the central zone. The screen for printing according to claim 1, wherein each of the outer openings extends outwardly from the second direction by one of the two linear openings, and each of the outer openings is in the second direction. The length is 150~250μm. The printing screen according to claim 1, wherein each of the outer openings has a length of 20 to 40 μm in the first direction, and each of the outer blocking portions has a length of 20 to 30 μm in the first direction. The screen for printing according to claim 1, wherein each of the linear openings is The length in the second direction is 100 to 200 μm. The screen for printing according to claim 1, wherein each of the central openings has a length in the second direction of 700 to 900. The printing screen according to claim 1, wherein each of the central openings has a length in the first direction of 60 to 120 μm, and each of the central blocking portions has a length in the first direction of 20 to 30 μm. The screen for printing according to claim 1, wherein the barrier layer further comprises a second ink-dropping pattern unit connected to the first ink-dropping pattern unit, the second ink-dropping pattern unit comprising a plurality of spaced apart in the first direction. And extending in the second direction respectively to the finger-shaped openings on opposite sides of the first ink-dropping pattern unit, each of the finger-shaped openings having a length in the first direction is smaller than the first ink-dropping pattern unit in the second The length in the direction. The screen for printing according to claim 7, wherein the central zone further has a plurality of auxiliary openings spaced along the first direction and extending respectively in the second direction to connect the two linear openings, the central portion The central opening and the central blocking portion are respectively arranged in a plurality of groups and are respectively located between the plurality of auxiliary openings spaced apart from each other, and each of the outer regions further has a plurality of intervals arranged along the first direction and respectively connected to the number a connection opening between one of the finger openings and one of the two linear openings, the outer opening and the outer blocking portion of each outer zone being a plurality of groups and respectively located at the two connections spaced apart Between the openings. The screen for printing according to claim 8, wherein each of the connection openings has a length in the first direction of 100 to 300 μm and is in the second direction. The length of the auxiliary opening is 150 to 250 μm, and the length of each auxiliary opening in the first direction is 150 to 250 μm. A method of manufacturing a solar cell, comprising: providing a substrate; forming an emitter layer on a light receiving surface side of the substrate; using a screen for printing according to any one of claims 1 to 6 on the substrate The conductive paste is printed on the light-receiving surface, and the conductive paste is coated on the light-receiving surface through the linear opening, the central opening and the outer opening of the first ink-dropping pattern unit of the printing screen, and a bus electrode is formed; A plurality of finger electrodes are disposed on the light receiving surface of the substrate; and a back electrode is disposed on a back surface of the substrate opposite to the light receiving surface. A method of manufacturing a solar cell, comprising: providing a substrate; forming an emitter layer on a light receiving surface side of the substrate; using a screen for printing according to any one of claims 7 to 9 on the substrate The conductive paste is printed on the light-receiving surface, and the conductive paste is passed through the linear opening of the first ink-dropping pattern unit of the printing screen, the central opening, the outer opening and the finger opening of the second ink-dropping pattern unit. And forming a bus electrode and a plurality of finger electrodes connected to the bus electrode; and disposing a back electrode on a back surface of the substrate opposite to the light receiving surface.