JP5524039B2 - Manufacturing method of solar cell - Google Patents

Description

  The present invention relates to a method for manufacturing a solar cell, and more specifically to a method for manufacturing a crystalline silicon solar cell.

  Conventionally, crystalline silicon solar cells have been generally used in solar cells. The crystalline silicon solar battery cell is a minimum unit cell constituting a solar battery manufactured from a single crystal silicon substrate or a polycrystalline silicon substrate, and has a size of about 100 mm square.

  A large area solar cell is manufactured by modularizing the crystalline silicon solar cell by a modularization process. The modularization process is disclosed in Non-Patent Document 1, for example.

  The modularization process includes a string process, a lay-up process, a lamination process, and the like, and there are, for example, Patent Document 1 and Patent Document 2 as prior documents disclosing these processes.

  In the string process, a plurality of crystalline silicon solar cells are connected in series using tab wiring. Here, in the conventional string process, the bus bar electrode of the crystalline silicon solar cell and the tab wiring are connected by soldering. What was produced by the said string process shall be called a solar cell string.

  The solar cell strings are arranged in a plurality of rows, and the crystalline silicon solar cells are arranged in a matrix. A crystal silicon solar cell arranged in a matrix is referred to as a matrix solar cell. Here, adjacent tab wirings existing at the ends of the matrix solar cells are electrically connected using the collecting electrodes.

  In the layup process, the matrix solar cells are sandwiched using a glass substrate, EVA (ethylene vinyl acetate), a protective member, and the like, and in the lamination process, the stacked body after the layup process is sealed.

JP 2005-216963 A JP 2001-60706 A

“Securities Report of NPC Co., Ltd.”, search on September 28, 2010, Internet <http://www.uforeader.com/v1/se/E01734_0070HHK9_5_5.html>

  However, when a solar cell is manufactured by the above process, there are the following problems.

  In other words, since the matrix solar cell is a structure in which a plurality of crystalline silicon solar cells are connected using only thin tab wiring, the mechanical strength is very low, and each crystalline silicon solar cell The position of the battery cell is likely to fluctuate.

  Therefore, in the layup process etc., the crystalline silicon solar cell and the tab wiring are mechanically damaged, and in the layup process and the lamination process, the position of the matrix solar cell on the glass substrate is easily shifted. Various problems occur. The occurrence of the problem has been a factor in the deterioration of the yield of solar cell modules.

  In addition, the crystalline silicon solar cell and the tab wiring are connected by soldering. In the soldering, since high temperature heat is applied, the member to which the high temperature is applied may be thermally damaged.

  Therefore, the present invention can reduce the damage of each constituent member constituting the solar cell during the manufacturing process, and prevent the displacement of the tab wiring and the crystalline silicon solar cell on the glass substrate. An object of the present invention is to provide a method for manufacturing a solar cell.

In order to achieve the above object, a method for manufacturing a solar cell according to the present invention includes (A) a step of producing a crystalline silicon solar cell having a bus bar electrode, and (B) the crystalline silicon solar cell. a glass substrate which is disposed, and bonding the tab wires, and a step of contacting a (C) after the step (B), the bus bar electrode and the tab wiring includes. Furthermore, the tab wiring is made of aluminum, and the step (B) is a step of bonding the tab wiring on the glass substrate by an ultrasonic vibration bonding process.

The method for producing a solar cell according to the present invention includes (A) a step of producing a crystalline silicon solar cell having a bus bar electrode, and (B) a glass substrate on which the crystalline silicon solar cell is disposed. and bonding the tab wires, and a step of contacting a (C) after the step (B), the bus bar electrode and the tab wiring includes. Furthermore, the tab wiring is made of aluminum, and the step (B) is a step of bonding the tab wiring on the glass substrate by an ultrasonic vibration bonding process.

  Therefore, the crystalline silicon solar cells arranged in a matrix reinforced by the glass substrate can be used in the steps after the lay-up step. Therefore, it can suppress that a crystalline silicon type photovoltaic cell receives a mechanical damage in a manufacturing process.

  Further, the tab wiring is bonded and fixed to the glass substrate before the crystalline silicon-based solar cells are arranged on the glass substrate. Therefore, it is possible to prevent the tab wiring from being displaced from a desired arrangement position on the glass substrate, and the tab wiring can be accurately arranged on the glass substrate. In addition, the crystalline silicon solar cells can be arranged above the glass substrate with reference to the tab wiring arranged with high accuracy. Therefore, in the method for manufacturing a solar cell according to the present invention, it is possible to perform an automated operation by a line process.

  Further, the bus bar electrode and the tab wiring are brought into contact with each other to enable electrical connection. That is, in the present invention, high-temperature processing (for example, 250 ° C. or higher) such as soldering is not performed in the connection between the bus bar electrode and the tab wiring. Therefore, it is possible to prevent the crystalline silicon solar cell from being damaged by a high temperature.

It is a top view which shows the structure of the crystalline silicon type solar cell 1 in which the various electrodes 2 and 3 were formed. 2 is a cross-sectional view showing a configuration of a crystalline silicon-based solar cell 1 including a bus bar electrode 3. FIG. It is sectional drawing which shows the structure of the tab wiring 5 which consists of a horizontal part 5a and the rising part 5b. FIG. 3 is a plan view showing a state of a plurality of tab wirings 5 and current collecting electrodes 8 arranged on the main surface of the glass substrate 6. FIG. 4 is a cross-sectional view showing a state of a plurality of tab wirings 5 and current collecting electrodes 8 arranged on the main surface of the glass substrate 6. 4 is a plan view showing a state in which a bus bar electrode 3 of a crystalline silicon-based solar battery cell 1 is brought into contact with a horizontal portion 5a of a tab wiring 5. FIG. 3 is a cross-sectional view showing a state where a bus bar electrode 3 of a crystalline silicon-based solar battery cell 1 is brought into contact with a horizontal portion 5a of a tab wiring 5. FIG. It is a top view which shows the mode after performing the process of defeating the rising part 5b of the tab wiring 5. FIG. It is sectional drawing which shows a mode after performing the process of defeating the rising part 5b of the tab wiring 5. FIG. 2 is a cross-sectional view showing a state in which adjacent crystalline silicon-based solar cells 1 are connected in series by tab wiring 5. FIG. It is a figure for demonstrating a layup process. 2 is a view showing a cross section of a crystalline silicon-based solar battery cell 1 in which a bus bar electrode 3 is coated with a conductive resin 40. FIG. FIG. 6 is a plan view showing a state in which a collecting electrode 8 is arranged on a predetermined tab wiring 5 after the rising portion 5b of the tab wiring 5 is tilted. FIG. 6 is a cross-sectional view showing a state in which the collecting electrode 8 is arranged on a predetermined tab wiring 5 after the rising portion 5b of the tab wiring 5 is tilted.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

<Embodiment>
First, a plurality of crystalline silicon solar cells are manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate. A plan view of each crystalline silicon solar cell is shown in FIG. Moreover, the AA cross section in FIG. 1 is shown in FIG.

  As shown in FIG. 1, a plurality of finger electrodes 2 are formed on the main surface of the crystalline silicon-based solar battery cell 1 in the horizontal direction of the drawing. Further, two bus bar electrodes 3 are formed on the main surface of the crystalline silicon-based solar battery cell 1 in the vertical direction of the drawing so as to be connected to each finger electrode 2.

  That is, the bus bar electrode 3 is disposed so as to intersect with the plurality of finger electrodes 2. Here, the bus bar electrode 3 is disposed in the vicinity of the edge of the crystalline silicon solar cell 1. As shown in FIG. 2, the front and back surfaces of the crystalline silicon solar cell 1 (first main surface: the lower surface of the cell 1 and second main surface: the upper surface of the cell 1) are shown in FIG. Finger electrodes 2 and two bus bar electrodes 3 are respectively formed.

  The thickness of the crystalline silicon solar cell 1 is about 0.1 to 0.2 mm, and has an area of about 100 mm. Inside the crystalline silicon solar cell, a PN junction is formed by impurity implantation.

  The finger electrode 2 and the bus bar electrode 3 are formed of silver paste or the like. The finger electrode 2 is an electrode for transmitting electricity generated by the photoelectric effect in the crystalline silicon solar cell 1. The bus bar electrode 3 collects electricity transmitted through each finger electrode 2.

  A plurality of tab wirings 5 are prepared separately from the production of the crystalline silicon solar cell 1. The tab wiring 5 has a line width of about 1 to 4 mm and a thickness of about 0.1 to 0.2 mm. Here, as shown in FIG. 3, each tab wiring 5 includes a horizontal portion 5a and a rising portion 5b connected to the horizontal portion 5a. The angle formed by the horizontal portion 5a and the rising portion 5b is, for example, about 90 °. The tab wiring 5 having the shape shown in FIG. 3 can be formed, for example, by bending a linear wiring in the middle.

  A glass substrate 6 having a thickness of about several millimeters is prepared, and the horizontal portion 5a of each tab wiring 5 is disposed at a predetermined location (a predetermined position according to the design) on the main surface of the glass substrate 6. In addition, two current collecting electrodes 8 are also arranged at predetermined positions (predetermined positions according to the design) on the main surface of the glass substrate 6. The current collecting electrode 8 is an electrode that collects electricity transmitted from each tab wiring 5. Further, the horizontal portion 5 a of each tab wiring 5 and the glass substrate 6 are joined, and each tab wiring 5 is fixed on the glass substrate 6. Further, the current collecting electrode 8 and the glass substrate 6 are joined, and the current collecting electrode 8 is fixed on the glass substrate 6.

  Here, when the tab wiring 5 is comprised from aluminum, each horizontal part 5a and the glass substrate 6 can be joined by ultrasonic vibration joining process. That is, a contact tool is brought into contact with each horizontal portion 5a, and a predetermined load is applied in a downward direction (a direction from the horizontal portion 5a toward the glass substrate 6) while ultrasonically vibrating the contact tool in the horizontal direction ( Ultrasonic vibration bonding process).

  FIG. 4 is a plan view showing a state after each tab wiring 5 is bonded to the glass substrate 6. FIG. 5 is a view showing a BB cross section of FIG. As shown in FIG. 4, on the main surface of the glass substrate 6, the tab wirings 5 are regularly and vertically arranged in an array. Moreover, the current collection electrode 8 is provided in the vicinity of the left and right edge portions of the glass substrate 6 and extends in the vertical direction of FIG. 4 as shown in FIG.

  Here, one collector electrode 8 is disposed below the horizontal portion 5a of each tab wiring 5 in the left end row of FIG. When the current collection electrode 8 is comprised from aluminum, the current collection electrode 8 and the glass substrate 6 can be joined by ultrasonic vibration joining process. Specifically, in the place where each tab wiring 5 in the left end row of FIG. 4 is disposed, the horizontal portion 5a of the glass substrate 6, the collecting electrode 8 and the tab wiring 5 is laminated in this order, and each horizontal portion 5a A predetermined load is applied in a downward direction (a direction from the horizontal portion 5a toward the glass substrate 6) while contacting the contact tool and ultrasonically vibrating the contact tool in the horizontal direction. Thereby, both the tab wiring 5 and the one collecting electrode 8 in the left end row are fixed to the glass substrate 6.

  Now, after the above process, in all the tab wirings 5 except for the tab wirings 5 in the left end column of FIG. 4, the first main parts of the crystalline silicon solar cells 1 shown in FIGS. The bus bar electrode 3 formed on the surface side is brought into contact. FIG. 6 is a plan view showing a state in which the bus bar electrode 3 formed on the first main surface side of some of the crystalline silicon solar cells 1 and the horizontal portion 5a are in contact with each other. FIG. 7 is a view showing a cross section taken along the line CC of FIG.

  As can be seen from FIG. 7, the bus bar electrode 3 formed on the first main surface side of the crystalline silicon solar cell 1 (below the crystalline silicon solar cell 1 in FIG. 7) It is in contact with the horizontal portion 5a. As shown in FIG. 2, two bus bar electrodes 3 are formed on each main surface of the crystalline silicon-based solar battery cell 1. Therefore, as can be seen from FIGS. 6 and 7, two tab wirings 5 are in contact with one crystalline silicon solar cell 1. That is, as many as the number of bus bar electrodes 3, tab wirings 5 are provided corresponding to the bus bar electrodes 3.

  Now, after placing each crystalline silicon solar cell 1 on the horizontal portion 5 a of the tab wiring 5, the rising portion 5 b of each tab wiring 5 is brought down. That is, in each tab wiring 5, the rising portion 5b is tilted so that the angle formed by the horizontal portion 5a and the rising portion 5b is larger than 90 ° so that the formed angle approaches 180 °. The state after the rising portion 5b is tilted is shown in the plan view of FIG. 8. FIG. 9 shows a cross section along the line DD in FIG. FIG. 10 is an enlarged cross-sectional view of a part of FIG.

  As can be seen from FIGS. 8, 9, and 10, the rising portion 5 b is tilted in the left-right direction of FIG. 8. As shown in FIG. 10, in the tab wiring 5 that is in contact with the bus bar electrode 3 formed on the first main surface of one of the crystalline silicon-based solar cells 1, the rising portion 5b falls and the rising portion 5b Is in contact with the bus bar electrode 3 formed on the second main surface of the crystalline silicon-based solar cell 1 adjacent in the arrangement direction of the tab wiring 5. In addition, the bus-bar electrode 3 formed in the 1st main surface of the said adjacent crystalline silicon type solar cell 1 is contacting the horizontal part 5a of the other tab wiring 5, as shown in FIG.

  Here, in each tab wiring 5 existing in the right end row of FIG. 8, the rising portion 5b is brought down to come into contact with the collecting electrode 8 existing near the right end side portion of the glass substrate 8 (see FIGS. 8 and 9). The other current collecting electrode 8 is disposed under the rising portion 5b of each tab wiring 5 in the right end row of FIG. When the current collection electrode 8 is comprised from aluminum, the current collection electrode 8 and the glass substrate 6 can be joined by ultrasonic vibration joining process.

  Specifically, in the place where the rising portion 5b of each tab wiring 5 in the right end row of FIG. 8 falls, the glass substrate 6, the other current collecting electrode 8 and the rising portion 5b of the tab wiring 5 are laminated in that order, A contact tool is brought into contact with the rising portion 5b, and a predetermined load is applied in a downward direction (a direction from the rising portion 5b toward the glass substrate 6) while ultrasonically vibrating the contact tool in the horizontal direction. Thereby, both the tab wiring 5 in the right end row and the other collecting electrode 8 are fixed to the glass substrate 6.

  As shown in FIG. 8, a plurality of crystalline silicon-based solar cells 1 are arranged in a matrix on the main surface of the glass substrate 6. In other words, as shown in FIG. 8, the solar cell strings 20 run in parallel over a plurality of rows on the main surface of the glass substrate 6. Here, as can be seen from FIGS. 8 and 9, each solar cell string 20 has a configuration in which a plurality of crystalline silicon solar cells 1 are connected in series by a tab wiring 5.

  Next, in the structure shown in FIGS. 8 and 9, an adhesive sheet (EVA sheet) 25 and a protective member 30 are laminated on the tab wiring 5 in this order (see the layup process, FIG. 11). Here, as the protective member 30, a glass substrate having a thickness of about 0.1 to 0.2 mm or a resin substrate such as PVA (polyvinyl alcohol) is employed. In the finished solar cell module, the glass substrate 6 exhibits a function of protecting the crystalline silicon solar cell 1 together with the protective member 30.

  Then, a lamination process is performed on the structure after the layup process. Specifically, the structure is placed under reduced pressure, and a predetermined load is applied while heating. Thereby, between the glass substrate 6 and the protection member 30, the crystalline silicon type solar cell 1 is sealed, and a solar cell module is completed.

  As can be seen from the above steps, in the method for manufacturing a solar cell according to the present invention, the crystalline silicon solar cells 1 are formed on the glass substrate 6 in the steps after the lay-up step. Here, in the finished solar cell module, the glass substrate 6 has not only a function of transmitting light but also a function of protecting the crystalline silicon solar cell 1.

  Therefore, the crystalline silicon solar cells 1 arranged in a matrix shape reinforced by the glass substrate 6 can be used in the steps after the lay-up step. Therefore, it can suppress that the crystalline silicon type photovoltaic cell 1 receives a mechanical damage in a manufacturing process.

  Further, in the method for manufacturing a solar cell according to the present invention, the tab wiring 5 is bonded and fixed to the glass substrate 6 before the crystalline silicon solar cell 1 is disposed on the glass substrate 6.

  Therefore, it is possible to prevent the tab wiring 5 from being displaced from a desired arrangement position on the glass substrate 6, and it is possible to accurately arrange the tab wiring 5 on the glass substrate 6. In addition, the crystalline silicon solar cells 1 can be arranged above the glass substrate 6 with reference to the tab wirings 5 arranged with high precision.

  In addition, since the tab wiring 5 can be accurately placed and fixed on the glass substrate 1 in the above process, the process after the placement process of the crystalline silicon solar cell 1 on the tab wiring 5 is automatically performed in the line process. It can also be done. In addition, arrangement | positioning and joining fixation of the tab wiring 5 on the glass substrate 1 can also be automatically performed according to design.

  When the tab wiring 5 and the current collecting electrode 8 are made of aluminum, an ultrasonic vibration bonding process is performed for bonding the members 5 and 8 and the glass substrate 8.

  In the ultrasonic vibration bonding process, a temperature as high as solder bonding is not applied to the glass substrate 6, the tab wiring 5, and the current collecting electrode 8. Therefore, thermal damage can be avoided and the solar cell module can be completed.

  In the above description, the electrical connection is made possible by bringing the bus bar electrode 3 and the tab wiring 5 into contact with each other. That is, in the connection between the bus bar electrode 3 and the tab wiring 5, high temperature processing such as soldering (for example, 180 ° C. or higher) is not performed in the present invention. Therefore, it is possible to prevent the crystalline silicon solar cell 1 and the like from being damaged by high temperatures.

  In addition, as shown in FIG. 12, you may employ | adopt the crystalline silicon type solar cell 1 by which the bus-bar electrode 3 was coated with the conductive resin 40. FIG. Each bus bar electrode 3 is in contact with the tab wiring 5 in the process described with reference to FIGS. 6 and 7 and the process described with reference to FIGS.

  When the crystalline silicon solar cell 1 shown in FIG. 12 is employed, the conductive resin 40 is melted by the temperature (about 160 ° C.) applied in the lamination step. Due to the dissolution of the conductive resin 40, the electrical connection between the bus bar electrode 3 and the tab wiring 5 becomes strong.

  In the above description, the tab wiring 5 is bent before joining the glass substrate 6 (that is, before joining to the glass substrate 5, the tab wiring 5 has a horizontal portion 5a and a rising portion 5b. Was).

  However, the rising portion 5b may be formed in the tab wiring 5 by bending a part of the linear tab wiring 5 on the glass substrate 6 and then bending the other part of the linear tab wiring 5. .

  In the above description, the glass substrate 6, the collecting electrode 8 and the tab wiring 5 are stacked in this order (the tab wiring 5 in the left end row in FIGS. 4 and 5 and the tab wiring in the right end row in FIGS. 8 and 9). 5 points attention).

  However, the current collecting electrode 8 may be disposed on the tab wiring 5 at a predetermined place after the rising portion 5b of the tab wiring 5 is tilted. FIG. 13 is a plan view of a structure when the process is employed, and FIG. 14 is a diagram showing a cross section taken along line EE of FIG.

  As shown in FIGS. 13 and 14, when the process is adopted, when attention is paid to the location of the tab wiring 5 in the left end row and the location of the tab wiring 5 in the right end row, the glass substrate 6, the tab wiring 5 and the current collecting electrode A laminate is formed in the order of 8. When the tab wiring 5 and the collecting electrode 8 are made of aluminum, the bonding and fixing of these members 5 and 8 to the glass substrate 6 can be performed by an ultrasonic vibration bonding process. In this case, a contact tool for performing ultrasonic vibration is brought into contact with the collecting electrode 8.

DESCRIPTION OF SYMBOLS 1 Crystalline silicon type solar cell 2 Finger electrode 3 Bus bar electrode 5 Tab wiring 5a Horizontal part 5b Rising part 6 Glass substrate 8 Current collecting electrode 20 Solar cell string 25 Adhesive sheet 30 Protection member 40 Conductive resin

Claims (5)

(A) producing a crystalline silicon solar cell having a bus bar electrode;
(B) a step of bonding tab wiring on a glass substrate on which the crystalline silicon-based solar cells are disposed;
(C) after the step (B), and a step of contacting the bus bar electrode and the tab wiring comprises,
The tab wiring is
Made of aluminum,
The step (B)
It is a step of bonding the tab wiring on the glass substrate by ultrasonic vibration bonding processing.
A method for manufacturing a solar cell. The step (B)
  The step of arranging the tab wiring having a rising portion in an array on the glass substrate by bonding a plurality of the tab wiring to the glass substrate,
  The bus bar electrode is
  Arranged on the first main surface and the second main surface of the crystalline silicon solar cell,
  The step (C)
  (C-1) After the step (B), in each of the tab wirings, the first main surface of the crystalline silicon-based solar cell is present on the tab wiring of the portion bonded to the glass substrate. Contacting the bus bar electrode;
  (C-2) Depressing the rising portion of the tab wiring causes the second of the crystalline silicon-based solar cells existing in the tab wiring arrangement direction and disposed on the other tab wiring. A step of contacting the bus bar electrode existing on the main surface and the rising part that has been brought down,
The manufacturing method of the solar cell of Claim 1 characterized by the above-mentioned.   (D) After the step (C), a step of laminating a protective member on the tab wiring;
  (E) After the step (D), further comprising a step of performing a laminating process so as to cover the glass substrate and the protective member.
The manufacturing method of the solar cell of Claim 2 characterized by the above-mentioned.   (F) further comprising a step of joining the current collecting electrodes made of aluminum, which electrically connect adjacent tab wirings, to the glass substrate by an ultrasonic vibration bonding process;
The manufacturing method of the solar cell of Claim 2 characterized by the above-mentioned.   The step (A)
  The bus bar electrode is coated with a conductive resin, the step of producing the crystalline silicon solar cell,
The method for manufacturing a solar cell according to any one of claims 1 to 4, wherein:

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