JP2012109423A - Soldering method and soldering device of interconnector of thin film solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soldering method of the interconnector of a thin film solar cell module.SOLUTION: In the soldering method of the interconnector of a thin film solar cell module, a solder plating interconnector (flat output conductive wire) is soldered to a metal rear surface electrode layer, i.e. the output electrode of a thin film solar cell module laminated on a glass substrate in the order of the metal rear surface electrode layer and the thin film solar cell module. While pressing the interconnector superimposed on the metal rear surface electrode layer by means of a hot press head, the solder plating is fused thermally and, at the same time, ultrasonic vibration is applied from the side surface of the hot press head.

Description

  The present invention relates to a method for joining an interconnector of a CIS thin film solar cell module, and more particularly to a technique using ultrasonic vibration in combination.

Solder that is heated and melted by heating means is brought into contact with a solder tip that has been vibrated ultrasonically by an ultrasonic vibrator, thereby applying ultrasonic vibration to the molten solder to improve wettability and soldering to the substrate to be soldered. An ultrasonic soldering apparatus using an ultrasonic soldering iron for performing the above has been put into practical use.
For example, according to a connection method using an indium solder-coated copper foil ribbon conductor, an ultrasonic soldering iron is used to securely and firmly connect the conductor electrode on the glass substrate and the ribbon conductor at low cost without damage. Solder connection can be performed while melting indium solder while heating (see, for example, Patent Document 1).

  Patent Document 1 does not disclose the heating means for the soldering iron, but the heating means for the ultrasonic soldering iron has a heater coil wound around the outer periphery of the tip of the ultrasonic soldering iron. Generally, the tip of the iron is heated by energizing the coil.

  However, in the connection method described in Patent Document 1, when a heater coil is used, the solder residue penetrates into the gap and obstructs ultrasonic vibration, and maintenance and cleaning for dealing with this take time and trouble. There is a problem that the heat transfer efficiency deteriorates when the width is widened.

  On the other hand, a thermocompression-type soldering method using a thermocompression-bonding head is also known, and even in this method, soldering quality and reliability due to insufficient solder wettability caused by an oxide film or a contaminated layer at the soldering joint are known. In order to eliminate the degradation, ultrasonic vibration is applied to the solder layer by combining ultrasonic vibration means with the thermocompression bonding head and applying ultrasonic vibration during thermocompression bonding, and a cavity (in the melted solder by the action of ultrasonic waves ( It is known that sufficient wettability can be ensured by generating voids and dissociating the oxide layer and the contamination layer in this cavity (see, for example, Patent Document 2).

JP 2007-207861 A Japanese Patent Laid-Open No. 06-350241

  In Patent Document 2, the thermocompression bonding head and the ultrasonic vibration means are combined, but the actual ultrasonic vibration means is an ultrasonic vibrator that generates a minute but powerful vibration of 20 to 35 kHz, and this frequency. It is connected to the thermocompression bonding head via an ultrasonic horn that resonates with and obtains a larger vibration.

  However, in order to uniformly maintain the vibration amplitude at the tip of the ultrasonic horn, there are predetermined limitations on the outer shapes of the ultrasonic vibrator and the ultrasonic horn. That is, when a large-sized ultrasonic horn is combined with the ultrasonic vibrator, there is a problem that not only the vibration distribution at the tip portion becomes non-uniform, but also a horizontal vibration is easily generated in addition to the vertical vibration. For this reason, an electronic device such as a thin film solar cell to be soldered according to the present invention is formed on a glass substrate, and the material of the electrode film (or layer) or conductive film (or layer) is other than Cu. A metal such as Mo or ITO (transparent conductive film) is used, and the thickness (or layer) of the film is very thin and the mechanical strength is low and easily damaged, which is not practical.

  Moreover, the ribbon wire connected to the electrode formed in the solar cell (not limited to the thin film system) to be soldered by the present invention is elongated, and it is better to change the outer dimensions of the thermocompression bonding head as necessary. Since it is practical, it is difficult to match the outer shapes of the ultrasonic vibrator and the ultrasonic horn, and it is difficult to avoid the above problem.

  The present invention has been made in order to solve the above-described problem, and separates the thermocompression bonding head and the ultrasonic horn and applies the ultrasonic vibration to the heat generating portion of the thermocompression bonding head to thereby reduce the outer shape of the ultrasonic horn. A first object is to provide a soldering method for a solder-plated interconnector (ribbon wire) of a thin-film solar cell module that can apply a uniform ultrasonic vibration by eliminating the relationship with the outer shape of the thermocompression bonding head. The second object is to provide a soldering apparatus that directly uses this joining method.

  The interconnector soldering method of the thin film solar cell module according to the present invention is the metal back electrode layer that is an output electrode of the thin film solar cell module laminated on the glass substrate in the order of the metal back electrode layer and the thin film solar cell module. A solder plating interconnector (flat output lead wire) is soldered to the metal plate by pressing and pressing the interconnector superimposed on the metal back electrode layer with a pressure / heating head to melt the solder plating. At the same time, ultrasonic vibration is applied from the side surface of the pressurizing / heating head (claim 1).

  In this soldering method, the ultrasonic vibration is applied so as to be in the longitudinal direction of the pressurizing / heating head (claim 2).

  In this soldering method, the ultrasonic vibration is applied to the pressurizing / heating head through a member having insulating properties and heat insulating properties.

The interconnector soldering apparatus of the thin film solar cell module according to the present invention is the metal back electrode layer which is an output electrode of the thin film solar cell module laminated on the glass substrate in the order of the metal back electrode layer and the thin film solar cell module. An apparatus for soldering a solder plating interconnector (flat output lead wire) to a pressure / heating head for pressing the solder plating interconnector superimposed on the metal back electrode and melting the solder plating;
Pressure means for applying a pressing force to the pressure / heating head, heating means for heating the pressure / heating head, and ultrasonic vibration for applying ultrasonic vibration to the pressure / heating head during solder plating melting A transmission unit and an ultrasonic vibration generation unit serving as an ultrasonic vibration source of the ultrasonic vibration transmission unit are provided (claim 4).

  In this soldering apparatus, the pressure / heating means and the ultrasonic vibration means are configured separately, and the ultrasonic vibration transmitting portion is pressed against the side surface of the pressure / heating head during soldering. A pressing means for applying a sonic vibration is provided (claim 5).

  Further, in this soldering apparatus, a member having an insulating property and a heat insulating property is disposed on the pressing side of the ultrasonic vibration transmitting portion (Claim 6).

  In this soldering apparatus, the heating means is a pulse heat power supply.

  According to the first to third aspects of the invention, since the ultrasonic vibration is applied from the side surface of the pressure / heating head, the outer shape of the pressure / heating head and the outer shape of the ultrasonic vibration transmitting portion are Therefore, it is possible to apply uniform ultrasonic vibration from the ultrasonic vibration transmission unit. Therefore, even if the soldering surface of the pressure / heating head becomes wider, the cavities (holes) generated in the solder melted by the action of ultrasonic waves become uniform, and the oxide layer of the soldering part corresponding to the soldering surface It is possible to ensure sufficient wettability by dissociating the contaminated layer.

  In particular, according to the invention of claim 2, since the ultrasonic vibration direction is the longitudinal direction of the pressurizing / heating head, stable ultrasonic vibration is applied to the pressurizing / heating head. It becomes possible to reduce the damage of the electrode film.

  In particular, according to the invention according to claim 3, since the ultrasonic vibration is applied to the pressurizing / heating head through a member having insulating properties and heat insulating properties, the ultrasonic vibration is resonated. Since there is no shunting of current from the pressurizing / heating head to the ultrasonic horn that amplifies vibration and heat transfer is reduced, almost all of the heat from the pressurizing / heating head generated by energization is soldered. Therefore, reliable temperature control becomes possible.

  According to the invention which concerns on Claim 4 thru | or 7, the soldering apparatus which can be used directly for the soldering method of Claim 1 thru | or 3 can be provided.

It is a schematic block diagram of the soldering apparatus of the solder plating interconnector of the thin film solar cell module of this invention. It is a general | schematic top view of the thin film solar cell module with which the solder plating interconnector was soldered using the soldering method of this invention. It is a schematic structure sectional view of a CIS type thin film solar cell device which is an example of a thin film solar cell module.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are indispensable as means for solving the present invention. Not always.

  FIG. 1 is a schematic diagram of a soldering apparatus for a solder plating interconnector of a thin film solar cell module of the present invention, and FIG. 2 is a diagram of a thin film solar cell module to which a solder plating interconnector is soldered using the soldering method of the present invention. FIG. 3 is a schematic plan view and FIG. 3 is a schematic sectional view of a CIS-based thin film solar cell device which is an example of a thin film solar cell module.

In FIG. 1, 1 is a CIS-based thin-film solar cell module (hereinafter also simply referred to as a solar cell module) formed on a metal back electrode layer 1C formed on a glass substrate 1A, and 2 is an output of the solar cell module 1. It is a solder plating interconnector (hereinafter also simply referred to as an interconnector) that is soldered to the metal back electrode layer 1C to be an electrode.
11 is a pressurizing / heating head that pressurizes and heats the interconnector 2 to the back surface metal electrode layer 1C, 13 is an elevating mechanism that raises and lowers the pressurizing / heating head 11 and applies a predetermined load, and 15 is an elevating mechanism 13 The pressure / heating head drive unit 17 presses the interconnector 2 against the back metal electrode layer 1 </ b> C with a predetermined load by driving, and a current 17 instantaneously sends a current to the pressure / heating head 11. This is a pulse heat power source that generates heat and melts the solder plating of the interconnector 2 with this heat. These constitute the solder melting part of the soldering apparatus.

  21 is an ultrasonic vibrator that vibrates at a predetermined frequency, 23 is an ultrasonic horn that resonates with the ultrasonic vibration generated by the ultrasonic vibrator 21 and increases its amplitude, and 25 is an ultrasonic wave from the ultrasonic horn 23. A member (for example, glass) 27 having an insulating property and a heat insulating property for preventing transmission of heat from the pressurizing / heating head 11 to the ultrasonic horn 23 side when applying vibration to the pressurizing / heating head 11; An ultrasonic oscillator that vibrates the ultrasonic vibrator 21 with ultrasonic waves, 29 has an ultrasonic vibrator 21 and an ultrasonic horn 23 when applying ultrasonic vibration to the pressurizing / heating head 11, and has insulation and heat insulation properties. It is an ultrasonic vibration transmission drive unit that controls the movement of the member 25 (left-right direction in FIG. 1). By these, the ultrasonic vibration application part of a soldering apparatus is comprised.

  The pressurizing / heating head 11 or the ultrasonic vibration transmission drive unit 29 constitutes an interconnector soldering device for the thin-film solar cell module.

  Since the present invention will be described by taking a CIS-based (generic name including CIS, CIGS, CIGSS, etc.) thin-film solar cell module as an example of the thin-film solar cell module, the CIS-based thin-film solar cell module will be described first with reference to FIG.

  The CIS-based thin film solar cell module 1 is obtained by electrically connecting a plurality of CIS-based thin-film solar cell devices 1 ′ through a conductive pattern. As shown in FIG. On the glass substrate 1A, an alkali barrier layer 1B (may be omitted if necessary), a metal back electrode layer (Mo is optimal) 1C, a p-type CIS light absorption layer 1D, an n-type high resistance buffer layer 1E, a pn heterojunction device having a substrate structure in which high-quality thin film layers are sequentially laminated in the order of an n-type transparent conductive film window layer 1F.

The light absorption layer 1D is a multi-component compound semiconductor thin film, particularly an I-III-VI group ₂ chalcopyrite semiconductor, for example, copper indium selenide, copper indium selenide, gallium selenide, copper gallium selenide, Copper indium gallium selenide, copper indium sulphide disulfide, copper indium sulphide disulfide, copper indium sulphide indium gallium disulfide, thin film of selenium disulfide, copper indium sulphide indium gallium selenide as a surface layer It consists of p-type semiconductors. As described above, the light absorption layer 1D is made of CIS, CIGS, CIGSS, and the like. The thin film solar cell module having such a light absorption layer 1D as a constituent element is collectively referred to as a CIS-based thin film solar cell module.

Next, the soldering method of the interconnector of the thin film solar cell module according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, solder-plated interconnector 2 is soldered to ultrathin metal back electrode layer (output electrode) 1C such as Mo on the end of glass substrate 1A.

First, the thin film solar cell module 1 (see FIG. 3) formed as described above is prepared and placed on a mounting table (not shown).
Next, the solder plating interconnector 2 whose length is adjusted in accordance with the outer shape of the thin film solar cell module 1 is prepared and placed on the metal back electrode layer (output electrode) 1 </ b> C of the thin film solar cell module 1.

  The solder plating layer of the solder plating interconnector 2 is preferably thick enough for soldering, but preliminary solder may be supplied to the position where the interconnector 2 is soldered if necessary. These solders should be lead-free solders in consideration of the environment.

  Next, the elevating mechanism 13 is operated under the control of the pressurizing / heating head drive unit 15 to lower the pressurizing / heating head 11 and press the interconnector 2 against the output electrode 1C. The load at this time is detected by a detection sensor and fed back to the pressurizing / heating head driving unit 15 and controlled so that a predetermined load is applied.

  When a predetermined load is applied, a pulsed current is supplied from the pulse heat power supply 17 to the pressurizing / heating head 11. The tip of the pressurizing / heating head 11 generates heat by this current, and the solder plating or preliminary solder of the interconnector 2 is melted by this heat. At this time, the temperature of the tip is detected by a detection sensor, fed back to the pulse heat power supply 17, and the current is increased or decreased so as to reach a predetermined temperature.

  In addition, when a predetermined load is applied as described above, the ultrasonic vibration transmission drive unit 29 causes the ultrasonic vibration transmission unit (the ultrasonic transducer 21, the ultrasonic horn 23, and the member 25 having insulating properties and heat insulation properties). The tip of the member 25 having insulation and heat insulation is pressed against the side surface of the pressurizing / heating head 21 with a predetermined load.

  When the solder is melted, an ultrasonic signal is oscillated from the ultrasonic oscillator 27 and supplied to the ultrasonic transducer 21. In this way, the ultrasonic vibrator 21 starts ultrasonic vibration with a predetermined amplitude, and the amplitude of the ultrasonic vibration is amplified by resonating with the ultrasonic horn 23 so that the member 25 having insulating properties and heat insulating properties is provided. To the pressurizing / heating head 11. Due to this ultrasonic vibration, the pressurizing / heating head 11 is vibrated with ultrasonic waves (in the left-right direction in FIG. 1) and propagated to the molten solder.

  This propagated ultrasonic vibration creates a cavity (hole) in the molten solder, and the oxide layer and the contaminated layer are dissociated in the cavity to ensure sufficient wettability. Further, voids contained in the molten solder are discharged by this ultrasonic vibration. For this reason, the reliability of soldering is improved. At this time, the heat from the pressurizing / heating head 21 is prevented from being transmitted to the ultrasonic horn 23 by the member 25 having insulating properties and heat insulating properties. Can be executed.

  On the other hand, when the solder is melted, the pressurizing / heating head 11 is lowered accordingly. For this reason, the pressurizing / heating head 11 is in close contact with the interconnector 2 and the output electrode 1C in a state where a load is applied. Here, although the amplitude is not large when ultrasonic vibration is applied as described above (several tens of μm), since the output electrode 1C is extremely thin as described above and is easily damaged, the ultrasonic vibration direction is It is preferable to be in the longitudinal direction of the interconnector 2.

  Further, the load by the pressure / heating head 11 is reduced by the feedback control of the load detection described above to weaken the adhesion between the interconnector 2 and the output electrode 1C so that the ultrasonic vibration is not applied to the output electrode 1C as it is. It is good. Further, the position of the pressurizing / heating head 11 is detected, and the detected position is fed back to the pressurizing / heating head driving unit 15 to float a predetermined distance (several μm to several tens of μm), and the pressurizing / heating head, interface It is preferable to provide a gap between the connector 2 and the output electrode 1C so that ultrasonic vibration is not applied to the output electrode 1C.

  The pressurizing / heating head 11 integrated with the lifting mechanism 13 and its supporting mechanism (not shown) so that ultrasonic vibrations are uniformly applied to the pressing surface of the interconnector 2 of the pressurizing / heating head 11. ) Is preferably a structure that can be moved in a small distance parallel to the ultrasonic vibration direction.

  Thus, a predetermined load, a predetermined current, and a predetermined ultrasonic vibration are applied to the pressurizing / heating head 11 for a predetermined time. Thereafter, the oscillation of the ultrasonic oscillator 27 is stopped to stop the ultrasonic vibration, and the ultrasonic vibration transmission unit is separated from the pressurizing / heating head 11 under the control of the ultrasonic vibration transmission drive unit 29. At the same time, the supply of the pulse current from the pulse heat power supply 17 is stopped, the heat generation of the pressurizing / heating head 11 is stopped, and the temperature of the pressurizing / heating head 11 is lowered. Then, after the melted solder is solidified, the pressure / heating head 11 is raised via the lifting mechanism 13 under the control of the pressure / heating head 15.

  In this way, the soldering to the output electrode 1C of the interconnector 2 is completed.

  Although the present embodiment has been described in detail as described above, it is easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Also, the configuration and operation of the soldering apparatus are not limited to those described in this embodiment, and various modifications such as omitting some of the components or adding other components are possible. is there.

DESCRIPTION OF SYMBOLS 1 Thin film solar cell module 1A Glass substrate 1C Metal back electrode layer (output electrode)
DESCRIPTION OF SYMBOLS 2 Solder plating interconnector 11 Pressurization / heating head 13 Elevating mechanism 15 Pressurization / heating head drive part 21 Ultrasonic vibrator 23 Ultrasonic horn 25 Member provided with insulation and heat insulation 27 Ultrasonic oscillator 29 Ultrasonic vibration transmission drive Part

Claims (7)

This is a method of soldering a solder plating interconnector (flat output conductor) to the metal back electrode layer, which is an output electrode of a thin film solar cell module laminated in order of a metal back electrode layer and a thin film solar cell module on a glass substrate. And
While pressing the interconnector superimposed on the metal back electrode layer with a pressurization / heating head, the solder plating is melted by heating, and at the same time, ultrasonic vibration is applied from the side of the pressurization / heating head. A method for soldering an interconnector of a thin film solar cell module.   2. The method of soldering an interconnector to a thin film solar cell module according to claim 1, wherein the ultrasonic vibration is applied so as to be in the longitudinal direction of the pressurizing / heating head.   2. The method of soldering an interconnector to a thin film solar cell module according to claim 1, wherein the ultrasonic vibration is applied to the pressurizing / heating head through a member having insulating properties and heat insulating properties. This is an apparatus for soldering a solder plating interconnector (flat output conductor) to the metal back electrode layer which is an output electrode of a thin film solar cell module in which a metal back electrode layer and a thin film solar cell module are laminated in this order on a glass substrate. And
A pressurizing / heating head for pressing the solder plating interconnector superimposed on the metal back electrode and melting the solder plating;
Pressurizing means for applying a pressing force to the pressurizing / heating head;
Heating means for heating the pressurizing / heating head;
An ultrasonic vibration transmitting unit for applying ultrasonic vibration to the pressure / heating head when the solder plating is melted;
An apparatus for soldering an interconnector to a thin-film solar cell module, comprising: an ultrasonic vibration generating unit that serves as an ultrasonic vibration source of the ultrasonic vibration transmitting unit. The pressurizing / heating means and the ultrasonic vibration means are configured separately,
5. The interconnector to a thin film solar cell module according to claim 4, further comprising pressing means for applying ultrasonic vibration by pressing the ultrasonic vibration transmitting portion against a side surface of the pressure / heating head during soldering. Soldering equipment.   5. The apparatus for soldering an interconnector to a thin-film solar cell module according to claim 4, wherein a member having an insulating property and a heat insulating property is disposed on the pressing side of the ultrasonic vibration transmitting portion.   5. The apparatus for soldering an interconnector to a thin film solar cell module according to claim 4, wherein the heating means is a pulse heat power source.

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