JP2011082030A - Ultrasonic connecting device, wire connecting device of thin film solar cell, and wiring connecting method of thin film solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an ultrasonic connecting device in which position displacement is suppressed and wiring is connected precisely. <P>SOLUTION: The ultrasonic connecting device (wiring connecting device of thin film solar cell) has a first disk (disc form tool) 1A and a second disk (disc form tool) 1B formed in a disc shape in which the outer peripheral parts are pushed to a bus bar wiring 15 and made to be vibrated ultrasonically and to rotatably move toward the longitudinal direction of the bus bar wiring 15, and the rear face electrode 14 is supersonically welded with the bus bar wiring 15. As for the first disk 1A and the second disk 1B, two spots are simultaneously welded that are apart by a prescribed distance in a direction intersecting at right angles with the moving direction of welding. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic connection device and wiring connection of a thin film solar cell.

  In the conventional thin film solar cell wiring connection method, a metal ribbon wire such as aluminum or copper is connected to the conductive substrate by ultrasonic welding to the conductive substrate exposed at both ends of the power generation elements connected in series. The example which does is disclosed (for example, refer patent document 1).

  Ultrasonic welding is performed by running on a bus bar at 20 to 50 kHz while applying an appropriate load to the head using an ultrasonic seam welder.

  Further, as an apparatus for welding a long metal thin plate, an apparatus for welding while rotating a peripheral surface of a disk-shaped tool that vibrates ultrasonically in a long direction is known. For example, in Patent Document 2, the thickness of the metal thin plate is 0.40 mm or less, the width of the overlapping portion of the metal thin plates is 1.5 to 4.0 mm, the pressing force of the tool is 50 kgf or more, and the amplitude of the tool is 20 μm. It is shown that the metal sheets are welded with sufficient strength by setting the above. As welding progresses, the overlapped portion may be displaced so as to separate due to the pressing force of the tool. It is stated that when a plurality of ultrasonic welders are arranged separately in the overlapped portion and welded at two points separated in the welding movement direction, the overlapped portion is not separated.

JP 2000-4034 A Japanese Patent Laid-Open No. 7-9169

  However, according to the above conventional technique, in the wiring connection method for connecting the wiring such as the metal ribbon line to the conductive substrate, there is a problem that the wiring material is laterally shifted by applying the ultrasonic wave. Before the ultrasonic welding, it is necessary to fix the metal ribbon wire by some method or to position it so that it does not shift when ultrasonic waves are applied.

  Even in the above-described method of welding at two points separated in the welding movement direction of the overlapped portion of Patent Document 2, it is insufficient to prevent a shift during application of ultrasonic waves.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain an ultrasonic connection device capable of accurately performing wiring connection while suppressing displacement. Moreover, it aims at obtaining the wiring connection method of the thin film solar cell which applied this ultrasonic connection apparatus to the wiring of a thin film solar cell, and the thin film solar cell wiring connection method performed using this ultrasonic connection device.

  In order to solve the above-described problems and achieve the object, the ultrasonic connecting apparatus of the present invention is an apparatus for ultrasonically welding a long thin metal plate superimposed on a conductive base to the conductive base along the longitudinal direction. The disk is formed and the outer periphery is pressed against a long metal thin plate and ultrasonically vibrated while rotating in the longitudinal direction of the long metal thin plate to ultrasonically weld the conductive substrate and the long metal thin plate. An ultrasonic connecting device provided with a disk-shaped tool, the first disk-shaped tool having a first disk-shaped tool and a second disk-shaped tool provided so as to face each other with their rotational axes substantially coincided with each other. And the second disk-shaped tool is characterized in that two locations separated by a predetermined distance in the direction orthogonal to the welding moving direction are welded simultaneously.

  The thin-film solar cell wiring connection device of the present invention is a device that ultrasonically welds the long bus bar wiring superimposed on the back electrode of the thin-film solar cell to the back electrode along the longitudinal direction. In a thin-film solar cell wiring connection device comprising a disk-like tool that ultrasonically welds the back electrode and the bus bar wiring by rotating the outer peripheral portion against the bus bar wiring and rotating in the longitudinal direction of the bus bar wiring while ultrasonically vibrating. , A first disk-shaped tool and a second disk-shaped tool provided so as to face each other with the rotation axis cores substantially coincided with each other. The first disk-shaped tool and the second disk-shaped tool are welded. Two locations separated by a predetermined distance in a direction perpendicular to the moving direction are welded simultaneously.

  In addition, the thin film solar cell wiring connection method of the present invention includes a thin film solar cell that ultrasonically welds the back electrode of the thin film solar cell and the long bus bar wiring superimposed on the back electrode along the longitudinal direction of the bus bar wiring. In the wiring connection method, the rotating shaft cores are roughly opposed to each other and are arranged to face each other, forming a disk shape, pressing the outer peripheral portion against the bus bar wiring and rotating it in the longitudinal direction of the bus bar wiring while rotating the back bar electrode. The first disk-shaped tool and the second disk-shaped tool that ultrasonically weld the bus bar wiring and the bus bar wiring are simultaneously welded at two locations separated by a predetermined distance in the direction perpendicular to the longitudinal direction of the bus bar wiring. And

  According to the present invention, the first disk-shaped tool and the second disk-shaped tool are simultaneously welded at two locations separated by a predetermined distance in the direction orthogonal to the welding moving direction. ), The force to shift the metal thin plate in the direction perpendicular to the moving direction of the welding is offset, and the metal thin plate does not shift laterally.

FIG. 1 is a perspective view for explaining connection of bus bar wiring by a single ultrasonic head. FIG. 2 is a cross-sectional view for considering the balance of forces acting on the bus bar wiring during ultrasonic welding of a single ultrasonic head. FIG. 3 is a cross-sectional view showing the balance when the disk is tilted during ultrasonic welding of a single ultrasonic head. FIG. 4 is a perspective view of a main part of the ultrasonic connection device of the present embodiment. FIG. 5 is a schematic diagram showing a portion of the first disc and the second disc viewed from the side. FIG. 6 is a cross-sectional view for considering the balance of forces acting on the bus bar wiring during ultrasonic welding of two ultrasonic heads.

  Embodiments of an ultrasonic connection device, a thin film solar cell wiring connection device, and a thin film solar cell wiring connection method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment FIG. 1 is a perspective view for explaining connection of bus bar wiring by a single ultrasonic head. The ultrasonic head 5 comprises a disk (disk-shaped tool) 1 and a spindle 2 that rotationally drives the disk 1. The metal thin plate 15). The disk 1 applies two forces as shown by arrows in FIG. That is, there are a force P for pressing the bus bar wiring 15 against the back electrode 14 and a force U in the ultrasonic application direction of the bus bar wiring 15 in the short axis direction (left and right direction in FIG. 1, the axial direction of the spindle 2). Further, the spindle 2 is rotated so that the disk 1 rolls without slipping corresponding to the moving speed S of the ultrasonic head.

  FIG. 2 is a cross-sectional view for considering the balance of forces acting on the bus bar wiring during ultrasonic welding. A pressing force P and an ultrasonic force U are used. Here, the ultrasonic force U is expressed by the following equation.

      U = A · sin (ωt) Amplitude A, angular velocity ω, time t

  If the applied ultrasonic wave is ideally uniaxially vibrated, the surfaces of the bus bar wiring 15 and the back electrode 14 are ideally flat, and the surface contact state is uniform, of the forces acting on the bus bar wiring 15, The ultrasonic force U balances with the friction force μP between the bus bar wiring 15 and the back electrode 14 (μ: friction coefficient), and the bus bar wiring 15 does not shift laterally in the bus bar wiring width direction during ultrasonic welding. However, even if the surfaces of the bus bar wiring 15 and the back electrode 14 are ideally flat, for example, as shown in FIG. 3, the ultrasonic head 5 (disk 1) may be in contact with the workpiece at an angle of 20 °. For example, the resultant force FP of the vertical component applied to the bus bar wiring 15 is Pcos 20 ° −Usin 20 °, and the resultant force FS of the horizontal component is Ucos 20 ° + Usin 20 °. Although the threshold value of the force at the time of lateral displacement depends on the coefficient of static friction, the pressing force P is weakened and the lateral displacement force U is increased, so that lateral displacement is likely to occur. Further, in practice, the ultrasonic vibration is elliptical vibration instead of uniaxial vibration, and the bus bar wiring 15 moves by overcoming the frictional force caused by the pressing force P. Further, when the bus bar wiring 15 is deformed or the surface of the back electrode 14 is non-uniform, P and U are similarly generated to cause elliptical vibration and the bus bar wiring is laterally displaced.

  FIG. 4 is a perspective view of a main part of the ultrasonic connection device of the present embodiment (the ultrasonic welder main body is not shown). The ultrasonic connection device (wiring connection device for a thin film solar cell) according to the present embodiment has long bus bar wires (metal thin plates) 15 and 16 superimposed on a back electrode (conductive base) 14 of the thin film solar cell. Ultrasonic welding is performed on the back electrode 14 along the direction (FIG. 4 shows the welding of the bus bar wiring 15 to the back electrode 14).

  The ultrasonic connection device includes an ultrasonic unit 10 that is movable relative to the thin-film solar cell 20 placed on a bed by a numerical control device and an orthogonal drive shaft mechanism (not shown). The ultrasonic unit 10 is configured to include a first head 5 and a second head 6 that are provided to face each other with their rotational axes substantially coincided with each other, and a column 9 that supports them. The first head 5 has a first disk (disk-shaped tool) 1A and a spindle 2A for driving the first disk 1A. The second head 6 has a second disk (disk-shaped tool) 1B that faces the first disk 1A, and a spindle 2B that drives the second disk 1B. Each of the first head 5 and the second head 6 has an ultrasonic wave generation source.

  The thin-film solar cell 20 is formed on the glass substrate 11 so that the transparent electrode 12, the thin-film power generation layer 13, and the back electrode 14 are stacked in this order, and the bus bar wiring 15, The electric power is taken out of the thin film solar cell 20 by 16. In general, the transparent electrode 12, the thin-film power generation layer 13, and the back electrode 14 are formed in an elongated strip shape, and are connected in series in the width direction of the strip by the transparent electrode 12 and the back electrode 14, and the back electrodes 14 at both ends in the connection direction. Further, a bus bar wiring 15 for taking out electric power is overlaid. The bus bar wiring 15 is a ribbon-like thin metal plate. Not only when the bus bar wiring 15 is directly connected to the back electrode 14, but also when another electrode along the back electrode 14 or the transparent electrode 12 is provided on the substrate, and this electrode and the bus bar wiring 15 are connected. There is also. The bus bar wiring 15 is made of a material such as an alloy such as aluminum or copper, and has a thickness of 0.05 to 0.2 mm, a width of 2 to 8 mm, and a length of about 1 to 1.5 m.

  In the step of connecting the bus bar wiring 15 on the thin film solar cell 20, first, the bus bar wiring 15 is placed on the electrode of the thin film solar cell 20, and then the first disk 1 </ b> A and the second disk 1 </ b> B from above the bus bar wiring 15. Are brought into contact with each other, and the back electrode 14 and the bus bar wirings 15 and 16 are ultrasonically welded.

  In the ultrasonic welding, the outer peripheral portions of two opposing disks 1A and 1B that are ultrasonically vibrated are simultaneously brought into contact with the bus bar wiring 15, and the disk 1A moves in the longitudinal direction of the bus bar wiring 15 while rotating. Accordingly, two bonding marks 17 are formed simultaneously, and the bus bar wiring 15 and the back electrode 14 are connected. The direction between two positions that are in contact with each other at the same time is in a direction orthogonal to the moving direction of welding.

  The interval between the opposing disks 1A and 1B is set to an appropriate interval according to the object to be processed, that is, the width of the bus bar wiring 15 in this embodiment. For example, when welding the bus bar wiring 15 having a width of 2 mm, the interval between the disks 1 may be set to 1 to 1.5 mm or the like. Further, in order to cope with various bus bar wiring widths and to optimize the adhesive strength, it is desirable that the ultrasonic connection device is provided with a variable mechanism for adjusting the distance between the opposing disks 1A and 1B.

  FIG. 5 is a schematic diagram showing a state where the first disk 1A and the second disk 1B are viewed from the side. The first disk 1A and the second disk 1B are arranged to face each other, and are inclined in a square shape so that the inclinations of the bus bar wiring 15 are opposite to each other and the size θ is the same. . In the case of the present embodiment, the first disk 1A and the second disk 1B are arranged so as to form an angle θ with respect to the normal of the bus bar wiring 15. Further, the first disk 1A and the second disk 1B facing each other are caused to vibrate in opposite phases with a phase shifted by π / 2 with respect to the vibration direction projected on the glass substrate 11 of the rotation axes of the spindles 2A and 2B. Good. For example, UL vibration is applied to the left disk 1 in FIG. 5 and UR vibration is applied to the right disk 1.

UL = A · sin (ωt)
UR = A · sin (ωt + π / 2)

  Next, the operation of the ultrasonic connection device of this embodiment will be described. FIG. 6 is a cross-sectional view for considering the balance of forces acting on the bus bar wiring during ultrasonic welding of two ultrasonic heads. When the components perpendicular to the glass substrate 11 of the force that the bus bar wiring 15 receives from the disks 1A and 1B are expressed by FP and FS and the left and right are expressed by the subscripts L and R, the force received by the bus bar wiring 15 is as follows. It is expressed in Here, the inclination angle of the disks 1A and 1B is θ.

Regarding the force received from the left disk 1 in FIG.
FPL = Pcos (θ) −ULsin (θ)
FSL = ULcos (θ) + Psin (θ)
Regarding the force received from the right disk 1 in FIG.
FPR = Pcos (θ) −URsin (θ)
FSR = URcos (θ) −Psin (θ)

The resultant force received by the entire bus bar wiring 15 is
Vertical component: FPL + FPR
= 2 × Pcos (θ) − {Asin (ωt) + Asin (ωt + π / 2)} sin (θ)
= 2 × Pcos (θ)
Horizontal component: FSL + FSR
= {Asin (ωt) cos (θ) + Asin (ωt + π / 2) cos (θ)} + {Psin (θ) −Psin (θ)}
= 0

  Ideally, the force for pressing the bus bar wiring 15 remains, but the force of the horizontal component due to the ultrasonic waves is canceled out so that the lateral shift does not occur. Here, when the first head 5 and the second head 6 are ideally not in contact with the bus bar wiring 15, a difference occurs in the first term of the horizontal component: FSL + FSR formula. Is sufficiently smaller than the original value (FSL or FSR). Further, even if the phases of the first disk 1A and the second disk 1B are not exactly opposite in phase, there is an effect of canceling each other as long as they are not completely in phase.

  In general, since the individual ultrasonic transmission sources are out of phase, the vibration of another ultrasonic transmission source may be transmitted to the first and second discs 1A and 1B facing each other. Further, if a phase modulation mechanism for shifting so as to cancel the phase of the ultrasonic vibration of the opposing disk is provided, the ultrasonic transmission source may be common. Further, the first disk 1A and the second disk 1B of the present embodiment are inclined so as to have an inverted C shape, but the same effect can be obtained with a C shape.

  In the present embodiment, the displacement of the bus bar wiring 15 due to the vibrations in the axial direction of the first disk 1A and the second disk 1B facing each other is canceled out, so that there is an excellent positional displacement prevention effect. Also, two connection locations are formed simultaneously, increasing the connection strength. In addition, two positions that are in contact with each other at the same time are perpendicular to the moving direction, and symmetric processing with excellent positional deviation is possible up to the end of the bus bar wiring 15.

The actual applied materials and processing conditions are shown below.
Material Back electrode: Laminated film of Ag of 300 nm thickness and Al of 100 nm thickness Bus bar wiring: Aluminum ribbon wire of 2 mm width and 0.1 mm thickness

Processing conditions Load: 1-5kg
Frequency: 20-60kHz
Tilt angle: 1-10 degrees, -1-10 degrees

  As described above, the ultrasonic connecting device (the thin film solar cell wiring connecting device) according to the present embodiment forms a disk shape, presses the outer peripheral portion against the bus bar wiring 15, and ultrasonically vibrates the bus bar wiring 15 in the longitudinal direction. The first disk 1A has a first disk (disk-shaped tool) 1A and a second disk (disk-shaped tool) 1B that ultrasonically welds the back electrode 14 and the bus bar wiring 15 to each other. And the second disk 1B are welded simultaneously at two locations separated by a predetermined distance in a direction orthogonal to the welding moving direction. The force in the spindle axis direction acting on the bus bar wiring 15 is canceled, and the bus bar wiring 15 is not laterally displaced.

  In addition, the first disk 1A and the second disk 1B have a C shape or a reverse C shape in which the inclinations of the first and second disks 1A and 15B are opposite to each other and have the same size. Therefore, the force in the spindle axis direction acting on the bus bar wiring 15 is further canceled, and the bus bar wiring 15 is not laterally displaced.

  Furthermore, since the first disk 1A and the second disk 1B are ultrasonically vibrated in opposite phases, the force in the spindle axis direction acting on the bus bar wiring 15 is further canceled, and the bus bar wiring 15 may be laterally displaced. Further disappear.

  As described above, the ultrasonic connecting device according to the present invention has a disk shape, in particular, of an apparatus that ultrasonically welds a long thin metal sheet superimposed on a conductive substrate to the conductive substrate along the longitudinal direction. Ultrasonic equipped with a disk-shaped tool that ultrasonically welds the conductive substrate and the long metal thin plate by rotating the outer peripheral portion against the long metal thin plate while rotating and moving in the longitudinal direction of the long metal thin plate Suitable for connecting devices.

1,1A, 1B disc (disc-shaped tool)
2,2A, 2B Spindle 5 Ultrasonic head (left)
6 Ultrasonic head (right)
9 Column 10 Ultrasonic Unit 11 Glass Substrate 12 Transparent Electrode 13 Thin Film Power Generation Layer 14 Back Electrode (Conductive Substrate)
15 Busbar wiring (long metal sheet)
17 Bond marks 20 Thin film solar ionization

Claims (6)

An apparatus for ultrasonically welding a long thin metal sheet superposed on a conductive substrate to the conductive substrate along a longitudinal direction;
The conductive base and the long metal thin plate are ultrasonically welded by rotating in the longitudinal direction of the long metal thin plate while making a disk shape and pressing the outer peripheral portion against the long metal thin plate while vibrating ultrasonically. In an ultrasonic connecting device equipped with a disk-shaped tool that
A first disk-shaped tool and a second disk-shaped tool provided so as to be opposed to each other with the rotational axis cores substantially matched,
The ultrasonic connection device, wherein the first disk-shaped tool and the second disk-shaped tool are simultaneously welded at two locations separated by a predetermined distance in a direction orthogonal to a welding moving direction. The first disk-shaped tool and the second disk-shaped tool have a square shape or a reverse-shaped tool whose inclinations are opposite to each other in the opposite direction with respect to the long metal thin plate. The ultrasonic connection device according to claim 1, wherein the ultrasonic connection device is inclined so as to have a letter shape. The ultrasonic connection device according to claim 1 or 2, wherein the first disk-shaped tool and the second disk-shaped tool vibrate ultrasonically in mutually opposite phases. The conductive substrate is a back electrode of a thin film solar cell,
The ultrasonic connection device according to any one of claims 1 to 3, wherein the long metal thin plate is a bus bar wiring connected to the back electrode. It is a device for ultrasonic welding the long bus bar wiring superimposed on the back electrode of the thin film solar cell to the back electrode along the longitudinal direction,
A disk-shaped tool is formed that ultrasonically welds the back electrode and the bus bar wiring by rotating in the longitudinal direction of the bus bar wiring while forming a disk shape and pressing the outer peripheral portion against the bus bar wiring while vibrating ultrasonically. In the thin-film solar cell wiring connection device,
A first disk-shaped tool and a second disk-shaped tool provided so as to be opposed to each other with the rotational axis cores substantially matched,
The first disk-shaped tool and the second disk-shaped tool are simultaneously welded at two locations separated by a predetermined distance in a direction orthogonal to the welding moving direction. In a wiring connection method of a thin film solar cell in which a back electrode of a thin film solar cell and a long bus bar wiring superimposed on the back electrode are ultrasonically welded along a longitudinal direction of the bus bar wiring, The back electrode and the bus bar wiring are ultrasonically welded by rotating in the longitudinal direction of the bus bar wiring while ultrasonically vibrating the outer peripheral portion against the bus bar wiring. Wiring for a thin film solar cell characterized in that, using a first disk-shaped tool and a second disk-shaped tool, two locations that are separated by a predetermined distance in the direction orthogonal to the longitudinal direction of the bus bar wiring are simultaneously welded. Connection method.

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